civetweb.c

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/* Copyright (c) 2013-2021 the Civetweb developers
 * Copyright (c) 2004-2013 Sergey Lyubka
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
 
#if defined(__GNUC__) || defined(__MINGW32__)
#ifndef GCC_VERSION
#define GCC_VERSION                                                            \
    (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#endif
#if GCC_VERSION >= 40500
/* gcc diagnostic pragmas available */
#define GCC_DIAGNOSTIC
#endif
#endif
 
#if defined(GCC_DIAGNOSTIC)
/* Disable unused macros warnings - not all defines are required
 * for all systems and all compilers. */
#pragma GCC diagnostic ignored "-Wunused-macros"
/* A padding warning is just plain useless */
#pragma GCC diagnostic ignored "-Wpadded"
#endif
 
#if defined(__clang__) /* GCC does not (yet) support this pragma */
/* We must set some flags for the headers we include. These flags
 * are reserved ids according to C99, so we need to disable a
 * warning for that. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wreserved-id-macro"
#endif
 
#if defined(_WIN32)
#if !defined(_CRT_SECURE_NO_WARNINGS)
#define _CRT_SECURE_NO_WARNINGS /* Disable deprecation warning in VS2005 */
#endif
#if !defined(_WIN32_WINNT) /* defined for tdm-gcc so we can use getnameinfo */
#define _WIN32_WINNT 0x0502
#endif
#else
#if !defined(_GNU_SOURCE)
#define _GNU_SOURCE /* for setgroups(), pthread_setname_np() */
#endif
#if defined(__linux__) && !defined(_XOPEN_SOURCE)
#define _XOPEN_SOURCE 600 /* For flockfile() on Linux */
#endif
#if defined(__LSB_VERSION__) || defined(__sun)
#define NEED_TIMEGM
#define NO_THREAD_NAME
#endif
#if !defined(_LARGEFILE_SOURCE)
#define _LARGEFILE_SOURCE /* For fseeko(), ftello() */
#endif
#if !defined(_FILE_OFFSET_BITS)
#define _FILE_OFFSET_BITS 64 /* Use 64-bit file offsets by default */
#endif
#if !defined(__STDC_FORMAT_MACROS)
#define __STDC_FORMAT_MACROS /* <inttypes.h> wants this for C++ */
#endif
#if !defined(__STDC_LIMIT_MACROS)
#define __STDC_LIMIT_MACROS /* C++ wants that for INT64_MAX */
#endif
#if !defined(_DARWIN_UNLIMITED_SELECT)
#define _DARWIN_UNLIMITED_SELECT
#endif
#if defined(__sun)
#define __EXTENSIONS__  /* to expose flockfile and friends in stdio.h */
#define __inline inline /* not recognized on older compiler versions */
#endif
#endif
 
#if defined(__clang__)
/* Enable reserved-id-macro warning again. */
#pragma GCC diagnostic pop
#endif
 
 
#if defined(USE_LUA)
#define USE_TIMERS
#endif
 
#if defined(_MSC_VER)
/* 'type cast' : conversion from 'int' to 'HANDLE' of greater size */
#pragma warning(disable : 4306)
/* conditional expression is constant: introduced by FD_SET(..) */
#pragma warning(disable : 4127)
/* non-constant aggregate initializer: issued due to missing C99 support */
#pragma warning(disable : 4204)
/* padding added after data member */
#pragma warning(disable : 4820)
/* not defined as a preprocessor macro, replacing with '0' for '#if/#elif' */
#pragma warning(disable : 4668)
/* no function prototype given: converting '()' to '(void)' */
#pragma warning(disable : 4255)
/* function has been selected for automatic inline expansion */
#pragma warning(disable : 4711)
#endif
 
 
/* This code uses static_assert to check some conditions.
 * Unfortunately some compilers still do not support it, so we have a
 * replacement function here. */
#if defined(__STDC_VERSION__) && __STDC_VERSION__ > 201100L
#define mg_static_assert _Static_assert
#elif defined(__cplusplus) && __cplusplus >= 201103L
#define mg_static_assert static_assert
#else
char static_assert_replacement[1];
#define mg_static_assert(cond, txt)                                            \
    extern char static_assert_replacement[(cond) ? 1 : -1]
#endif
 
mg_static_assert(sizeof(int) == 4 || sizeof(int) == 8,
                 "int data type size check");
mg_static_assert(sizeof(void *) == 4 || sizeof(void *) == 8,
                 "pointer data type size check");
mg_static_assert(sizeof(void *) >= sizeof(int), "data type size check");
 
 
/* Select queue implementation. Diagnosis features originally only implemented
 * for the "ALTERNATIVE_QUEUE" have been ported to the previous queue
 * implementation (NO_ALTERNATIVE_QUEUE) as well. The new configuration value
 * "CONNECTION_QUEUE_SIZE" is only available for the previous queue
 * implementation, since the queue length is independent from the number of
 * worker threads there, while the new queue is one element per worker thread.
 *
 */
#if defined(NO_ALTERNATIVE_QUEUE) && defined(ALTERNATIVE_QUEUE)
/* The queues are exclusive or - only one can be used. */
#error                                                                         \
    "Define ALTERNATIVE_QUEUE or NO_ALTERNATIVE_QUEUE (or none of them), but not both"
#endif
#if !defined(NO_ALTERNATIVE_QUEUE) && !defined(ALTERNATIVE_QUEUE)
/* Use a default implementation */
#define NO_ALTERNATIVE_QUEUE
#endif
 
#if defined(NO_FILESYSTEMS) && !defined(NO_FILES)
/* File system access:
 * NO_FILES = do not serve any files from the file system automatically.
 * However, with NO_FILES CivetWeb may still write log files, read access
 * control files, default error page files or use API functions like
 * mg_send_file in callbacks to send files from the server local
 * file system.
 * NO_FILES only disables the automatic mapping between URLs and local
 * file names.
 * NO_FILESYSTEM = do not access any file at all. Useful for embedded
 * devices without file system. Logging to files in not available
 * (use callbacks instead) and API functions like mg_send_file are not
 * available.
 * If NO_FILESYSTEM is set, NO_FILES must be set as well.
 */
#error "Inconsistent build flags, NO_FILESYSTEMS requires NO_FILES"
#endif
 
/* DTL -- including winsock2.h works better if lean and mean */
#if !defined(WIN32_LEAN_AND_MEAN)
#define WIN32_LEAN_AND_MEAN
#endif
 
#if defined(__SYMBIAN32__)
/* According to https://en.wikipedia.org/wiki/Symbian#History,
 * Symbian is no longer maintained since 2014-01-01.
 * Support for Symbian has been removed from CivetWeb
 */
#error "Symbian is no longer maintained. CivetWeb no longer supports Symbian."
#endif /* __SYMBIAN32__ */
 
#if defined(__ZEPHYR__)
#include <ctype.h>
#include <fcntl.h>
#include <netdb.h>
#include <poll.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <time.h>
 
#include <zephyr/kernel.h>
 
/* Max worker threads is the max of pthreads minus the main application thread
 * and minus the main civetweb thread, thus -2
 */
#define MAX_WORKER_THREADS (CONFIG_MAX_PTHREAD_COUNT - 2)
 
#if defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
#define ZEPHYR_STACK_SIZE USE_STACK_SIZE
#else
#define ZEPHYR_STACK_SIZE (1024 * 16)
#endif
 
K_THREAD_STACK_DEFINE(civetweb_main_stack, ZEPHYR_STACK_SIZE);
K_THREAD_STACK_ARRAY_DEFINE(civetweb_worker_stacks,
                            MAX_WORKER_THREADS,
                            ZEPHYR_STACK_SIZE);
 
static int zephyr_worker_stack_index;
 
#endif
 
#if !defined(CIVETWEB_HEADER_INCLUDED)
/* Include the header file here, so the CivetWeb interface is defined for the
 * entire implementation, including the following forward definitions. */
#include "civetweb.h"
#endif
 
#if !defined(DEBUG_TRACE)
#if defined(DEBUG)
static void DEBUG_TRACE_FUNC(const char *func,
                             unsigned line,
                             PRINTF_FORMAT_STRING(const char *fmt),
                             ...) PRINTF_ARGS(3, 4);
 
#define DEBUG_TRACE(fmt, ...)                                                  \
    DEBUG_TRACE_FUNC(__func__, __LINE__, fmt, __VA_ARGS__)
 
#define NEED_DEBUG_TRACE_FUNC
#if !defined(DEBUG_TRACE_STREAM)
#define DEBUG_TRACE_STREAM stdout
#endif
 
#else
#define DEBUG_TRACE(fmt, ...)                                                  \
    do {                                                                       \
    } while (0)
#endif /* DEBUG */
#endif /* DEBUG_TRACE */
 
 
#if !defined(DEBUG_ASSERT)
#if defined(DEBUG)
#include <stdlib.h>
#define DEBUG_ASSERT(cond)                                                     \
    do {                                                                       \
        if (!(cond)) {                                                         \
            DEBUG_TRACE("ASSERTION FAILED: %s", #cond);                        \
            exit(2); /* Exit with error */                                     \
        }                                                                      \
    } while (0)
#else
#define DEBUG_ASSERT(cond)
#endif /* DEBUG */
#endif
 
 
#if defined(__GNUC__) && defined(GCC_INSTRUMENTATION)
void __cyg_profile_func_enter(void *this_fn, void *call_site)
    __attribute__((no_instrument_function));
 
void __cyg_profile_func_exit(void *this_fn, void *call_site)
    __attribute__((no_instrument_function));
 
void
__cyg_profile_func_enter(void *this_fn, void *call_site)
{
    if ((void *)this_fn != (void *)printf) {
        printf("E %p %p\n", this_fn, call_site);
    }
}
 
void
__cyg_profile_func_exit(void *this_fn, void *call_site)
{
    if ((void *)this_fn != (void *)printf) {
        printf("X %p %p\n", this_fn, call_site);
    }
}
#endif
 
 
#if !defined(IGNORE_UNUSED_RESULT)
#define IGNORE_UNUSED_RESULT(a) ((void)((a) && 1))
#endif
 
 
#if defined(__GNUC__) || defined(__MINGW32__)
 
/* GCC unused function attribute seems fundamentally broken.
 * Several attempts to tell the compiler "THIS FUNCTION MAY BE USED
 * OR UNUSED" for individual functions failed.
 * Either the compiler creates an "unused-function" warning if a
 * function is not marked with __attribute__((unused)).
 * On the other hand, if the function is marked with this attribute,
 * but is used, the compiler raises a completely idiotic
 * "used-but-marked-unused" warning - and
 *   #pragma GCC diagnostic ignored "-Wused-but-marked-unused"
 * raises error: unknown option after "#pragma GCC diagnostic".
 * Disable this warning completely, until the GCC guys sober up
 * again.
 */
 
#pragma GCC diagnostic ignored "-Wunused-function"
 
#define FUNCTION_MAY_BE_UNUSED /* __attribute__((unused)) */
 
#else
#define FUNCTION_MAY_BE_UNUSED
#endif
 
 
/* Some ANSI #includes are not available on Windows CE and Zephyr */
#if !defined(_WIN32_WCE) && !defined(__ZEPHYR__)
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#endif /* !_WIN32_WCE */
 
 
#if defined(__clang__)
/* When using -Weverything, clang does not accept it's own headers
 * in a release build configuration. Disable what is too much in
 * -Weverything. */
#pragma clang diagnostic ignored "-Wdisabled-macro-expansion"
#endif
 
#if defined(__GNUC__) || defined(__MINGW32__)
/* Who on earth came to the conclusion, using __DATE__ should rise
 * an "expansion of date or time macro is not reproducible"
 * warning. That's exactly what was intended by using this macro.
 * Just disable this nonsense warning. */
 
/* And disabling them does not work either:
 * #pragma clang diagnostic ignored "-Wno-error=date-time"
 * #pragma clang diagnostic ignored "-Wdate-time"
 * So we just have to disable ALL warnings for some lines
 * of code.
 * This seems to be a known GCC bug, not resolved since 2012:
 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431
 */
#endif
 
 
#if defined(__MACH__) && defined(__APPLE__) /* Apple OSX section */
 
#if defined(__clang__)
#if (__clang_major__ == 3) && ((__clang_minor__ == 7) || (__clang_minor__ == 8))
/* Avoid warnings for Xcode 7. It seems it does no longer exist in Xcode 8 */
#pragma clang diagnostic ignored "-Wno-reserved-id-macro"
#pragma clang diagnostic ignored "-Wno-keyword-macro"
#endif
#endif
 
#ifndef CLOCK_MONOTONIC
#define CLOCK_MONOTONIC (1)
#endif
#ifndef CLOCK_REALTIME
#define CLOCK_REALTIME (2)
#endif
 
#include <mach/clock.h>
#include <mach/mach.h>
#include <mach/mach_time.h>
#include <sys/errno.h>
#include <sys/time.h>
 
/* clock_gettime is not implemented on OSX prior to 10.12 */
static int
_civet_clock_gettime(int clk_id, struct timespec *t)
{
    memset(t, 0, sizeof(*t));
    if (clk_id == CLOCK_REALTIME) {
        struct timeval now;
        int rv = gettimeofday(&now, NULL);
        if (rv) {
            return rv;
        }
        t->tv_sec = now.tv_sec;
        t->tv_nsec = now.tv_usec * 1000;
        return 0;
 
    } else if (clk_id == CLOCK_MONOTONIC) {
        static uint64_t clock_start_time = 0;
        static mach_timebase_info_data_t timebase_ifo = {0, 0};
 
        uint64_t now = mach_absolute_time();
 
        if (clock_start_time == 0) {
            kern_return_t mach_status = mach_timebase_info(&timebase_ifo);
            DEBUG_ASSERT(mach_status == KERN_SUCCESS);
 
            /* appease "unused variable" warning for release builds */
            (void)mach_status;
 
            clock_start_time = now;
        }
 
        now = (uint64_t)((double)(now - clock_start_time)
                         * (double)timebase_ifo.numer
                         / (double)timebase_ifo.denom);
 
        t->tv_sec = now / 1000000000;
        t->tv_nsec = now % 1000000000;
        return 0;
    }
    return -1; /* EINVAL - Clock ID is unknown */
}
 
/* if clock_gettime is declared, then __CLOCK_AVAILABILITY will be defined */
#if defined(__CLOCK_AVAILABILITY)
/* If we compiled with Mac OSX 10.12 or later, then clock_gettime will be
 * declared but it may be NULL at runtime. So we need to check before using
 * it. */
static int
_civet_safe_clock_gettime(int clk_id, struct timespec *t)
{
    if (clock_gettime) {
        return clock_gettime(clk_id, t);
    }
    return _civet_clock_gettime(clk_id, t);
}
#define clock_gettime _civet_safe_clock_gettime
#else
#define clock_gettime _civet_clock_gettime
#endif
 
#endif
 
 
#if defined(_WIN32)
#define ERROR_TRY_AGAIN(err) ((err) == WSAEWOULDBLOCK)
#else
/* Unix might return different error codes indicating to try again.
 * For Linux EAGAIN==EWOULDBLOCK, maybe EAGAIN!=EWOULDBLOCK is history from
 * decades ago, but better check both and let the compiler optimize it. */
#define ERROR_TRY_AGAIN(err)                                                   \
    (((err) == EAGAIN) || ((err) == EWOULDBLOCK) || ((err) == EINTR))
#endif
 
#if defined(USE_ZLIB)
#include "zconf.h"
#include "zlib.h"
#endif
 
 
/********************************************************************/
/* CivetWeb configuration defines */
/********************************************************************/
 
/* Maximum number of threads that can be configured.
 * The number of threads actually created depends on the "num_threads"
 * configuration parameter, but this is the upper limit. */
#if !defined(MAX_WORKER_THREADS)
#define MAX_WORKER_THREADS (1024 * 64) /* in threads (count) */
#endif
 
/* Timeout interval for select/poll calls.
 * The timeouts depend on "*_timeout_ms" configuration values, but long
 * timeouts are split into timouts as small as SOCKET_TIMEOUT_QUANTUM.
 * This reduces the time required to stop the server. */
#if !defined(SOCKET_TIMEOUT_QUANTUM)
#define SOCKET_TIMEOUT_QUANTUM (2000) /* in ms */
#endif
 
/* Do not try to compress files smaller than this limit. */
#if !defined(MG_FILE_COMPRESSION_SIZE_LIMIT)
#define MG_FILE_COMPRESSION_SIZE_LIMIT (1024) /* in bytes */
#endif
 
#if !defined(PASSWORDS_FILE_NAME)
#define PASSWORDS_FILE_NAME ".htpasswd"
#endif
 
/* Initial buffer size for all CGI environment variables. In case there is
 * not enough space, another block is allocated. */
#if !defined(CGI_ENVIRONMENT_SIZE)
#define CGI_ENVIRONMENT_SIZE (4096) /* in bytes */
#endif
 
/* Maximum number of environment variables. */
#if !defined(MAX_CGI_ENVIR_VARS)
#define MAX_CGI_ENVIR_VARS (256) /* in variables (count) */
#endif
 
/* General purpose buffer size. */
#if !defined(MG_BUF_LEN) /* in bytes */
#define MG_BUF_LEN (1024 * 8)
#endif
 
 
/********************************************************************/
 
/* Helper macros */
#if !defined(ARRAY_SIZE)
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
#endif
 
#include <stdint.h>
 
/* Standard defines */
#if !defined(INT64_MAX)
#define INT64_MAX (9223372036854775807)
#endif
 
#define SHUTDOWN_RD (0)
#define SHUTDOWN_WR (1)
#define SHUTDOWN_BOTH (2)
 
mg_static_assert(MAX_WORKER_THREADS >= 1,
                 "worker threads must be a positive number");
 
mg_static_assert(sizeof(size_t) == 4 || sizeof(size_t) == 8,
                 "size_t data type size check");
 
 
#if defined(_WIN32) /* WINDOWS include block */
#include <malloc.h> /* *alloc( */
#include <stdlib.h> /* *alloc( */
#include <time.h>   /* struct timespec */
#include <windows.h>
#include <winsock2.h> /* DTL add for SO_EXCLUSIVE */
#include <ws2tcpip.h>
 
typedef const char *SOCK_OPT_TYPE;
 
/* For a detailed description of these *_PATH_MAX defines, see
 * https://github.com/civetweb/civetweb/issues/937. */
 
/* UTF8_PATH_MAX is a char buffer size for 259 BMP characters in UTF-8 plus
 * null termination, rounded up to the next 4 bytes boundary */
#define UTF8_PATH_MAX (3 * 260)
/* UTF16_PATH_MAX is the 16-bit wchar_t buffer size required for 259 BMP
 * characters plus termination. (Note: wchar_t is 16 bit on Windows) */
#define UTF16_PATH_MAX (260)
 
#if !defined(_IN_PORT_T)
#if !defined(in_port_t)
#define in_port_t u_short
#endif
#endif
 
#if defined(_WIN32_WCE)
#error "WinCE support has ended"
#endif
 
#include <direct.h>
#include <io.h>
#include <process.h>
 
 
#define MAKEUQUAD(lo, hi)                                                      \
    ((uint64_t)(((uint32_t)(lo)) | ((uint64_t)((uint32_t)(hi))) << 32))
#define RATE_DIFF (10000000) /* 100 nsecs */
#define EPOCH_DIFF (MAKEUQUAD(0xd53e8000, 0x019db1de))
#define SYS2UNIX_TIME(lo, hi)                                                  \
    ((time_t)((MAKEUQUAD((lo), (hi)) - EPOCH_DIFF) / RATE_DIFF))
 
/* Visual Studio 6 does not know __func__ or __FUNCTION__
 * The rest of MS compilers use __FUNCTION__, not C99 __func__
 * Also use _strtoui64 on modern M$ compilers */
#if defined(_MSC_VER)
#if (_MSC_VER < 1300)
#define STRX(x) #x
#define STR(x) STRX(x)
#define __func__ __FILE__ ":" STR(__LINE__)
#define strtoull(x, y, z) ((unsigned __int64)_atoi64(x))
#define strtoll(x, y, z) (_atoi64(x))
#else
#define __func__ __FUNCTION__
#define strtoull(x, y, z) (_strtoui64(x, y, z))
#define strtoll(x, y, z) (_strtoi64(x, y, z))
#endif
#endif /* _MSC_VER */
 
 
#define ERRNO ((int)(GetLastError()))
#define NO_SOCKLEN_T
 
 
#if defined(_WIN64) || defined(__MINGW64__)
#if !defined(SSL_LIB)
 
#if defined(OPENSSL_API_3_0)
#define SSL_LIB "libssl-3-x64.dll"
#define CRYPTO_LIB "libcrypto-3-x64.dll"
#endif
 
#if defined(OPENSSL_API_1_1)
#define SSL_LIB "libssl-1_1-x64.dll"
#define CRYPTO_LIB "libcrypto-1_1-x64.dll"
#endif /* OPENSSL_API_1_1 */
 
#if defined(OPENSSL_API_1_0)
#define SSL_LIB "ssleay64.dll"
#define CRYPTO_LIB "libeay64.dll"
#endif /* OPENSSL_API_1_0 */
 
#endif
#else /* defined(_WIN64) || defined(__MINGW64__) */
#if !defined(SSL_LIB)
 
#if defined(OPENSSL_API_3_0)
#define SSL_LIB "libssl-3.dll"
#define CRYPTO_LIB "libcrypto-3.dll"
#endif
 
#if defined(OPENSSL_API_1_1)
#define SSL_LIB "libssl-1_1.dll"
#define CRYPTO_LIB "libcrypto-1_1.dll"
#endif /* OPENSSL_API_1_1 */
 
#if defined(OPENSSL_API_1_0)
#define SSL_LIB "ssleay32.dll"
#define CRYPTO_LIB "libeay32.dll"
#endif /* OPENSSL_API_1_0 */
 
#endif /* SSL_LIB */
#endif /* defined(_WIN64) || defined(__MINGW64__) */
 
 
#define O_NONBLOCK (0)
#if !defined(W_OK)
#define W_OK (2) /* http://msdn.microsoft.com/en-us/library/1w06ktdy.aspx */
#endif
#define _POSIX_
#define INT64_FMT "I64d"
#define UINT64_FMT "I64u"
 
#define WINCDECL __cdecl
#define vsnprintf_impl _vsnprintf
#define access _access
#define mg_sleep(x) (Sleep(x))
 
#define pipe(x) _pipe(x, MG_BUF_LEN, _O_BINARY)
#if !defined(popen)
#define popen(x, y) (_popen(x, y))
#endif
#if !defined(pclose)
#define pclose(x) (_pclose(x))
#endif
#define close(x) (_close(x))
#define dlsym(x, y) (GetProcAddress((HINSTANCE)(x), (y)))
#define RTLD_LAZY (0)
#define fseeko(x, y, z) ((_lseeki64(_fileno(x), (y), (z)) == -1) ? -1 : 0)
#define fdopen(x, y) (_fdopen((x), (y)))
#define write(x, y, z) (_write((x), (y), (unsigned)z))
#define read(x, y, z) (_read((x), (y), (unsigned)z))
#define flockfile(x) ((void)pthread_mutex_lock(&global_log_file_lock))
#define funlockfile(x) ((void)pthread_mutex_unlock(&global_log_file_lock))
#define sleep(x) (Sleep((x)*1000))
#define rmdir(x) (_rmdir(x))
#if defined(_WIN64) || !defined(__MINGW32__)
/* Only MinGW 32 bit is missing this function */
#define timegm(x) (_mkgmtime(x))
#else
time_t timegm(struct tm *tm);
#define NEED_TIMEGM
#endif
 
 
#if !defined(fileno)
#define fileno(x) (_fileno(x))
#endif /* !fileno MINGW #defines fileno */
 
typedef struct {
    CRITICAL_SECTION sec; /* Immovable */
} pthread_mutex_t;
typedef DWORD pthread_key_t;
typedef HANDLE pthread_t;
typedef struct {
    pthread_mutex_t threadIdSec;
    struct mg_workerTLS *waiting_thread; /* The chain of threads */
} pthread_cond_t;
 
#if !defined(__clockid_t_defined)
typedef DWORD clockid_t;
#endif
#if !defined(CLOCK_MONOTONIC)
#define CLOCK_MONOTONIC (1)
#endif
#if !defined(CLOCK_REALTIME)
#define CLOCK_REALTIME (2)
#endif
#if !defined(CLOCK_THREAD)
#define CLOCK_THREAD (3)
#endif
#if !defined(CLOCK_PROCESS)
#define CLOCK_PROCESS (4)
#endif
 
 
#if defined(_MSC_VER) && (_MSC_VER >= 1900)
#define _TIMESPEC_DEFINED
#endif
#if !defined(_TIMESPEC_DEFINED)
struct timespec {
    time_t tv_sec; /* seconds */
    long tv_nsec;  /* nanoseconds */
};
#endif
 
#if !defined(WIN_PTHREADS_TIME_H)
#define MUST_IMPLEMENT_CLOCK_GETTIME
#endif
 
#if defined(MUST_IMPLEMENT_CLOCK_GETTIME)
#define clock_gettime mg_clock_gettime
static int
clock_gettime(clockid_t clk_id, struct timespec *tp)
{
    FILETIME ft;
    ULARGE_INTEGER li, li2;
    BOOL ok = FALSE;
    double d;
    static double perfcnt_per_sec = 0.0;
    static BOOL initialized = FALSE;
 
    if (!initialized) {
        QueryPerformanceFrequency((LARGE_INTEGER *)&li);
        perfcnt_per_sec = 1.0 / li.QuadPart;
        initialized = TRUE;
    }
 
    if (tp) {
        memset(tp, 0, sizeof(*tp));
 
        if (clk_id == CLOCK_REALTIME) {
 
            /* BEGIN: CLOCK_REALTIME = wall clock (date and time) */
            GetSystemTimeAsFileTime(&ft);
            li.LowPart = ft.dwLowDateTime;
            li.HighPart = ft.dwHighDateTime;
            li.QuadPart -= 116444736000000000; /* 1.1.1970 in filedate */
            tp->tv_sec = (time_t)(li.QuadPart / 10000000);
            tp->tv_nsec = (long)(li.QuadPart % 10000000) * 100;
            ok = TRUE;
            /* END: CLOCK_REALTIME */
 
        } else if (clk_id == CLOCK_MONOTONIC) {
 
            /* BEGIN: CLOCK_MONOTONIC = stopwatch (time differences) */
            QueryPerformanceCounter((LARGE_INTEGER *)&li);
            d = li.QuadPart * perfcnt_per_sec;
            tp->tv_sec = (time_t)d;
            d -= (double)tp->tv_sec;
            tp->tv_nsec = (long)(d * 1.0E9);
            ok = TRUE;
            /* END: CLOCK_MONOTONIC */
 
        } else if (clk_id == CLOCK_THREAD) {
 
            /* BEGIN: CLOCK_THREAD = CPU usage of thread */
            FILETIME t_create, t_exit, t_kernel, t_user;
            if (GetThreadTimes(GetCurrentThread(),
                               &t_create,
                               &t_exit,
                               &t_kernel,
                               &t_user)) {
                li.LowPart = t_user.dwLowDateTime;
                li.HighPart = t_user.dwHighDateTime;
                li2.LowPart = t_kernel.dwLowDateTime;
                li2.HighPart = t_kernel.dwHighDateTime;
                li.QuadPart += li2.QuadPart;
                tp->tv_sec = (time_t)(li.QuadPart / 10000000);
                tp->tv_nsec = (long)(li.QuadPart % 10000000) * 100;
                ok = TRUE;
            }
            /* END: CLOCK_THREAD */
 
        } else if (clk_id == CLOCK_PROCESS) {
 
            /* BEGIN: CLOCK_PROCESS = CPU usage of process */
            FILETIME t_create, t_exit, t_kernel, t_user;
            if (GetProcessTimes(GetCurrentProcess(),
                                &t_create,
                                &t_exit,
                                &t_kernel,
                                &t_user)) {
                li.LowPart = t_user.dwLowDateTime;
                li.HighPart = t_user.dwHighDateTime;
                li2.LowPart = t_kernel.dwLowDateTime;
                li2.HighPart = t_kernel.dwHighDateTime;
                li.QuadPart += li2.QuadPart;
                tp->tv_sec = (time_t)(li.QuadPart / 10000000);
                tp->tv_nsec = (long)(li.QuadPart % 10000000) * 100;
                ok = TRUE;
            }
            /* END: CLOCK_PROCESS */
 
        } else {
 
            /* BEGIN: unknown clock */
            /* ok = FALSE; already set by init */
            /* END: unknown clock */
        }
    }
 
    return ok ? 0 : -1;
}
#endif
 
 
#define pid_t HANDLE /* MINGW typedefs pid_t to int. Using #define here. */
 
static int pthread_mutex_lock(pthread_mutex_t *);
static int pthread_mutex_unlock(pthread_mutex_t *);
static void path_to_unicode(const struct mg_connection *conn,
                            const char *path,
                            wchar_t *wbuf,
                            size_t wbuf_len);
 
/* All file operations need to be rewritten to solve #246. */
 
struct mg_file;
 
static const char *mg_fgets(char *buf, size_t size, struct mg_file *filep);
 
 
/* POSIX dirent interface */
struct dirent {
    char d_name[UTF8_PATH_MAX];
};
 
typedef struct DIR {
    HANDLE handle;
    WIN32_FIND_DATAW info;
    struct dirent result;
} DIR;
 
#if defined(HAVE_POLL)
#define mg_pollfd pollfd
#else
struct mg_pollfd {
    SOCKET fd;
    short events;
    short revents;
};
#endif
 
/* Mark required libraries */
#if defined(_MSC_VER)
#pragma comment(lib, "Ws2_32.lib")
#endif
 
#else /* defined(_WIN32) - WINDOWS vs UNIX include block */
 
#include <inttypes.h>
 
/* Linux & co. internally use UTF8 */
#define UTF8_PATH_MAX (PATH_MAX)
 
typedef const void *SOCK_OPT_TYPE;
 
#if defined(ANDROID)
typedef unsigned short int in_port_t;
#endif
 
#if !defined(__ZEPHYR__)
#include <arpa/inet.h>
#include <ctype.h>
#include <dirent.h>
#include <grp.h>
#include <limits.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <poll.h>
#include <pthread.h>
#include <pwd.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#if defined(USE_X_DOM_SOCKET)
#include <sys/un.h>
#endif
#endif
 
#define vsnprintf_impl vsnprintf
 
#if !defined(NO_SSL_DL) && !defined(NO_SSL)
#include <dlfcn.h>
#endif
 
#if defined(__MACH__) && defined(__APPLE__)
#define SSL_LIB "libssl.dylib"
#define CRYPTO_LIB "libcrypto.dylib"
#else
#if !defined(SSL_LIB)
#define SSL_LIB "libssl.so"
#endif
#if !defined(CRYPTO_LIB)
#define CRYPTO_LIB "libcrypto.so"
#endif
#endif
#if !defined(O_BINARY)
#define O_BINARY (0)
#endif /* O_BINARY */
#define closesocket(a) (close(a))
#define mg_mkdir(conn, path, mode) (mkdir(path, mode))
#define mg_remove(conn, x) (remove(x))
#define mg_sleep(x) (usleep((x)*1000))
#define mg_opendir(conn, x) (opendir(x))
#define mg_closedir(x) (closedir(x))
#define mg_readdir(x) (readdir(x))
#define ERRNO (errno)
#define INVALID_SOCKET (-1)
#define INT64_FMT PRId64
#define UINT64_FMT PRIu64
typedef int SOCKET;
#define WINCDECL
 
#if defined(__hpux)
/* HPUX 11 does not have monotonic, fall back to realtime */
#if !defined(CLOCK_MONOTONIC)
#define CLOCK_MONOTONIC CLOCK_REALTIME
#endif
 
/* HPUX defines socklen_t incorrectly as size_t which is 64bit on
 * Itanium.  Without defining _XOPEN_SOURCE or _XOPEN_SOURCE_EXTENDED
 * the prototypes use int* rather than socklen_t* which matches the
 * actual library expectation.  When called with the wrong size arg
 * accept() returns a zero client inet addr and check_acl() always
 * fails.  Since socklen_t is widely used below, just force replace
 * their typedef with int. - DTL
 */
#define socklen_t int
#endif /* hpux */
 
#define mg_pollfd pollfd
 
#endif /* defined(_WIN32) - WINDOWS vs UNIX include block */
 
/* In case our C library is missing "timegm", provide an implementation */
#if defined(NEED_TIMEGM)
static inline int
is_leap(int y)
{
    return (y % 4 == 0 && y % 100 != 0) || y % 400 == 0;
}
 
static inline int
count_leap(int y)
{
    return (y - 1969) / 4 - (y - 1901) / 100 + (y - 1601) / 400;
}
 
time_t
timegm(struct tm *tm)
{
    static const unsigned short ydays[] = {
        0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};
    int year = tm->tm_year + 1900;
    int mon = tm->tm_mon;
    int mday = tm->tm_mday - 1;
    int hour = tm->tm_hour;
    int min = tm->tm_min;
    int sec = tm->tm_sec;
 
    if (year < 1970 || mon < 0 || mon > 11 || mday < 0
        || (mday >= ydays[mon + 1] - ydays[mon]
                        + (mon == 1 && is_leap(year) ? 1 : 0))
        || hour < 0 || hour > 23 || min < 0 || min > 59 || sec < 0 || sec > 60)
        return -1;
 
    time_t res = year - 1970;
    res *= 365;
    res += mday;
    res += ydays[mon] + (mon > 1 && is_leap(year) ? 1 : 0);
    res += count_leap(year);
 
    res *= 24;
    res += hour;
    res *= 60;
    res += min;
    res *= 60;
    res += sec;
    return res;
}
#endif /* NEED_TIMEGM */
 
 
/* va_copy should always be a macro, C99 and C++11 - DTL */
#if !defined(va_copy)
#define va_copy(x, y) ((x) = (y))
#endif
 
 
#if defined(_WIN32)
/* Create substitutes for POSIX functions in Win32. */
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif
 
 
static pthread_mutex_t global_log_file_lock;
 
FUNCTION_MAY_BE_UNUSED
static DWORD
pthread_self(void)
{
    return GetCurrentThreadId();
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_key_create(
    pthread_key_t *key,
    void (*_ignored)(void *) /* destructor not supported for Windows */
)
{
    (void)_ignored;
 
    if ((key != 0)) {
        *key = TlsAlloc();
        return (*key != TLS_OUT_OF_INDEXES) ? 0 : -1;
    }
    return -2;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_key_delete(pthread_key_t key)
{
    return TlsFree(key) ? 0 : 1;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_setspecific(pthread_key_t key, void *value)
{
    return TlsSetValue(key, value) ? 0 : 1;
}
 
 
FUNCTION_MAY_BE_UNUSED
static void *
pthread_getspecific(pthread_key_t key)
{
    return TlsGetValue(key);
}
 
#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif
 
static struct pthread_mutex_undefined_struct *pthread_mutex_attr = NULL;
#else
static pthread_mutexattr_t pthread_mutex_attr;
#endif /* _WIN32 */
 
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
#endif
 
static pthread_mutex_t global_lock_mutex;
 
 
FUNCTION_MAY_BE_UNUSED
static void
mg_global_lock(void)
{
    (void)pthread_mutex_lock(&global_lock_mutex);
}
 
 
FUNCTION_MAY_BE_UNUSED
static void
mg_global_unlock(void)
{
    (void)pthread_mutex_unlock(&global_lock_mutex);
}
 
 
#if defined(_WIN64)
mg_static_assert(SIZE_MAX == 0xFFFFFFFFFFFFFFFFu, "Mismatch for atomic types");
#elif defined(_WIN32)
mg_static_assert(SIZE_MAX == 0xFFFFFFFFu, "Mismatch for atomic types");
#endif
 
 
/* Atomic functions working on ptrdiff_t ("signed size_t").
 * Operations: Increment, Decrement, Add, Maximum.
 * Up to size_t, they do not an atomic "load" operation.
 */
FUNCTION_MAY_BE_UNUSED
static ptrdiff_t
mg_atomic_inc(volatile ptrdiff_t *addr)
{
    ptrdiff_t ret;
 
#if defined(_WIN64) && !defined(NO_ATOMICS)
    ret = InterlockedIncrement64(addr);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
    ret = InterlockedIncrement(addr);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
    ret = __sync_add_and_fetch(addr, 1);
#else
    mg_global_lock();
    ret = (++(*addr));
    mg_global_unlock();
#endif
    return ret;
}
 
 
FUNCTION_MAY_BE_UNUSED
static ptrdiff_t
mg_atomic_dec(volatile ptrdiff_t *addr)
{
    ptrdiff_t ret;
 
#if defined(_WIN64) && !defined(NO_ATOMICS)
    ret = InterlockedDecrement64(addr);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
    ret = InterlockedDecrement(addr);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
    ret = __sync_sub_and_fetch(addr, 1);
#else
    mg_global_lock();
    ret = (--(*addr));
    mg_global_unlock();
#endif
    return ret;
}
 
 
#if defined(USE_SERVER_STATS) || defined(STOP_FLAG_NEEDS_LOCK)
static ptrdiff_t
mg_atomic_add(volatile ptrdiff_t *addr, ptrdiff_t value)
{
    ptrdiff_t ret;
 
#if defined(_WIN64) && !defined(NO_ATOMICS)
    ret = InterlockedAdd64(addr, value);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
    ret = InterlockedExchangeAdd(addr, value) + value;
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
    ret = __sync_add_and_fetch(addr, value);
#else
    mg_global_lock();
    *addr += value;
    ret = (*addr);
    mg_global_unlock();
#endif
    return ret;
}
 
 
FUNCTION_MAY_BE_UNUSED
static ptrdiff_t
mg_atomic_compare_and_swap(volatile ptrdiff_t *addr,
                           ptrdiff_t oldval,
                           ptrdiff_t newval)
{
    ptrdiff_t ret;
 
#if defined(_WIN64) && !defined(NO_ATOMICS)
    ret = InterlockedCompareExchange64(addr, newval, oldval);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
    ret = InterlockedCompareExchange(addr, newval, oldval);
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
    ret = __sync_val_compare_and_swap(addr, oldval, newval);
#else
    mg_global_lock();
    ret = *addr;
    if ((ret != newval) && (ret == oldval)) {
        *addr = newval;
    }
    mg_global_unlock();
#endif
    return ret;
}
 
 
static void
mg_atomic_max(volatile ptrdiff_t *addr, ptrdiff_t value)
{
    register ptrdiff_t tmp = *addr;
 
#if defined(_WIN64) && !defined(NO_ATOMICS)
    while (tmp < value) {
        tmp = InterlockedCompareExchange64(addr, value, tmp);
    }
#elif defined(_WIN32) && !defined(NO_ATOMICS)
    while (tmp < value) {
        tmp = InterlockedCompareExchange(addr, value, tmp);
    }
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
    while (tmp < value) {
        tmp = __sync_val_compare_and_swap(addr, tmp, value);
    }
#else
    mg_global_lock();
    if (*addr < value) {
        *addr = value;
    }
    mg_global_unlock();
#endif
}
 
 
static int64_t
mg_atomic_add64(volatile int64_t *addr, int64_t value)
{
    int64_t ret;
 
#if defined(_WIN64) && !defined(NO_ATOMICS)
    ret = InterlockedAdd64(addr, value);
#elif defined(_WIN32) && !defined(NO_ATOMICS)
    ret = InterlockedExchangeAdd64(addr, value) + value;
#elif defined(__GNUC__)                                                        \
    && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ > 0)))           \
    && !defined(NO_ATOMICS)
    ret = __sync_add_and_fetch(addr, value);
#else
    mg_global_lock();
    *addr += value;
    ret = (*addr);
    mg_global_unlock();
#endif
    return ret;
}
#endif
 
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic pop
#endif
 
 
#if defined(USE_SERVER_STATS)
 
struct mg_memory_stat {
    volatile ptrdiff_t totalMemUsed;
    volatile ptrdiff_t maxMemUsed;
    volatile ptrdiff_t blockCount;
};
 
 
static struct mg_memory_stat *get_memory_stat(struct mg_context *ctx);
 
 
static void *
mg_malloc_ex(size_t size,
             struct mg_context *ctx,
             const char *file,
             unsigned line)
{
    void *data = malloc(size + 2 * sizeof(uintptr_t));
    void *memory = 0;
    struct mg_memory_stat *mstat = get_memory_stat(ctx);
 
#if defined(MEMORY_DEBUGGING)
    char mallocStr[256];
#else
    (void)file;
    (void)line;
#endif
 
    if (data) {
        ptrdiff_t mmem = mg_atomic_add(&mstat->totalMemUsed, (ptrdiff_t)size);
        mg_atomic_max(&mstat->maxMemUsed, mmem);
 
        mg_atomic_inc(&mstat->blockCount);
        ((uintptr_t *)data)[0] = size;
        ((uintptr_t *)data)[1] = (uintptr_t)mstat;
        memory = (void *)(((char *)data) + 2 * sizeof(uintptr_t));
    }
 
#if defined(MEMORY_DEBUGGING)
    sprintf(mallocStr,
            "MEM: %p %5lu alloc   %7lu %4lu --- %s:%u\n",
            memory,
            (unsigned long)size,
            (unsigned long)mstat->totalMemUsed,
            (unsigned long)mstat->blockCount,
            file,
            line);
    DEBUG_TRACE("%s", mallocStr);
#endif
 
    return memory;
}
 
 
static void *
mg_calloc_ex(size_t count,
             size_t size,
             struct mg_context *ctx,
             const char *file,
             unsigned line)
{
    void *data = mg_malloc_ex(size * count, ctx, file, line);
 
    if (data) {
        memset(data, 0, size * count);
    }
    return data;
}
 
 
static void
mg_free_ex(void *memory, const char *file, unsigned line)
{
#if defined(MEMORY_DEBUGGING)
    char mallocStr[256];
#else
    (void)file;
    (void)line;
#endif
 
    if (memory) {
        void *data = (void *)(((char *)memory) - 2 * sizeof(uintptr_t));
        uintptr_t size = ((uintptr_t *)data)[0];
        struct mg_memory_stat *mstat =
            (struct mg_memory_stat *)(((uintptr_t *)data)[1]);
        mg_atomic_add(&mstat->totalMemUsed, -(ptrdiff_t)size);
        mg_atomic_dec(&mstat->blockCount);
 
#if defined(MEMORY_DEBUGGING)
        sprintf(mallocStr,
                "MEM: %p %5lu free    %7lu %4lu --- %s:%u\n",
                memory,
                (unsigned long)size,
                (unsigned long)mstat->totalMemUsed,
                (unsigned long)mstat->blockCount,
                file,
                line);
        DEBUG_TRACE("%s", mallocStr);
#endif
        free(data);
    }
}
 
 
static void *
mg_realloc_ex(void *memory,
              size_t newsize,
              struct mg_context *ctx,
              const char *file,
              unsigned line)
{
    void *data;
    void *_realloc;
    uintptr_t oldsize;
 
#if defined(MEMORY_DEBUGGING)
    char mallocStr[256];
#else
    (void)file;
    (void)line;
#endif
 
    if (newsize) {
        if (memory) {
            /* Reallocate existing block */
            struct mg_memory_stat *mstat;
            data = (void *)(((char *)memory) - 2 * sizeof(uintptr_t));
            oldsize = ((uintptr_t *)data)[0];
            mstat = (struct mg_memory_stat *)((uintptr_t *)data)[1];
            _realloc = realloc(data, newsize + 2 * sizeof(uintptr_t));
            if (_realloc) {
                data = _realloc;
                mg_atomic_add(&mstat->totalMemUsed, -(ptrdiff_t)oldsize);
#if defined(MEMORY_DEBUGGING)
                sprintf(mallocStr,
                        "MEM: %p %5lu r-free  %7lu %4lu --- %s:%u\n",
                        memory,
                        (unsigned long)oldsize,
                        (unsigned long)mstat->totalMemUsed,
                        (unsigned long)mstat->blockCount,
                        file,
                        line);
                DEBUG_TRACE("%s", mallocStr);
#endif
                mg_atomic_add(&mstat->totalMemUsed, (ptrdiff_t)newsize);
 
#if defined(MEMORY_DEBUGGING)
                sprintf(mallocStr,
                        "MEM: %p %5lu r-alloc %7lu %4lu --- %s:%u\n",
                        memory,
                        (unsigned long)newsize,
                        (unsigned long)mstat->totalMemUsed,
                        (unsigned long)mstat->blockCount,
                        file,
                        line);
                DEBUG_TRACE("%s", mallocStr);
#endif
                *(uintptr_t *)data = newsize;
                data = (void *)(((char *)data) + 2 * sizeof(uintptr_t));
            } else {
#if defined(MEMORY_DEBUGGING)
                DEBUG_TRACE("%s", "MEM: realloc failed\n");
#endif
                return _realloc;
            }
        } else {
            /* Allocate new block */
            data = mg_malloc_ex(newsize, ctx, file, line);
        }
    } else {
        /* Free existing block */
        data = 0;
        mg_free_ex(memory, file, line);
    }
 
    return data;
}
 
 
#define mg_malloc(a) mg_malloc_ex(a, NULL, __FILE__, __LINE__)
#define mg_calloc(a, b) mg_calloc_ex(a, b, NULL, __FILE__, __LINE__)
#define mg_realloc(a, b) mg_realloc_ex(a, b, NULL, __FILE__, __LINE__)
#define mg_free(a) mg_free_ex(a, __FILE__, __LINE__)
 
#define mg_malloc_ctx(a, c) mg_malloc_ex(a, c, __FILE__, __LINE__)
#define mg_calloc_ctx(a, b, c) mg_calloc_ex(a, b, c, __FILE__, __LINE__)
#define mg_realloc_ctx(a, b, c) mg_realloc_ex(a, b, c, __FILE__, __LINE__)
 
 
#else /* USE_SERVER_STATS */
 
 
static __inline void *
mg_malloc(size_t a)
{
    return malloc(a);
}
 
static __inline void *
mg_calloc(size_t a, size_t b)
{
    return calloc(a, b);
}
 
static __inline void *
mg_realloc(void *a, size_t b)
{
    return realloc(a, b);
}
 
static __inline void
mg_free(void *a)
{
    free(a);
}
 
#define mg_malloc_ctx(a, c) mg_malloc(a)
#define mg_calloc_ctx(a, b, c) mg_calloc(a, b)
#define mg_realloc_ctx(a, b, c) mg_realloc(a, b)
#define mg_free_ctx(a, c) mg_free(a)
 
#endif /* USE_SERVER_STATS */
 
 
static void mg_vsnprintf(const struct mg_connection *conn,
                         int *truncated,
                         char *buf,
                         size_t buflen,
                         const char *fmt,
                         va_list ap);
 
static void mg_snprintf(const struct mg_connection *conn,
                        int *truncated,
                        char *buf,
                        size_t buflen,
                        PRINTF_FORMAT_STRING(const char *fmt),
                        ...) PRINTF_ARGS(5, 6);
 
/* This following lines are just meant as a reminder to use the mg-functions
 * for memory management */
#if defined(malloc)
#undef malloc
#endif
#if defined(calloc)
#undef calloc
#endif
#if defined(realloc)
#undef realloc
#endif
#if defined(free)
#undef free
#endif
#if defined(snprintf)
#undef snprintf
#endif
#if defined(vsnprintf)
#undef vsnprintf
#endif
#define malloc DO_NOT_USE_THIS_FUNCTION__USE_mg_malloc
#define calloc DO_NOT_USE_THIS_FUNCTION__USE_mg_calloc
#define realloc DO_NOT_USE_THIS_FUNCTION__USE_mg_realloc
#define free DO_NOT_USE_THIS_FUNCTION__USE_mg_free
#define snprintf DO_NOT_USE_THIS_FUNCTION__USE_mg_snprintf
#if defined(_WIN32)
/* vsnprintf must not be used in any system,
 * but this define only works well for Windows. */
#define vsnprintf DO_NOT_USE_THIS_FUNCTION__USE_mg_vsnprintf
#endif
 
 
/* mg_init_library counter */
static int mg_init_library_called = 0;
 
#if !defined(NO_SSL)
#if defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)                       \
    || defined(OPENSSL_API_3_0)
static int mg_openssl_initialized = 0;
#endif
#if !defined(OPENSSL_API_1_0) && !defined(OPENSSL_API_1_1)                     \
    && !defined(OPENSSL_API_3_0) && !defined(USE_MBEDTLS)
#error "Please define OPENSSL_API_#_# or USE_MBEDTLS"
#endif
#if defined(OPENSSL_API_1_0) && defined(OPENSSL_API_1_1)
#error "Multiple OPENSSL_API versions defined"
#endif
#if defined(OPENSSL_API_1_1) && defined(OPENSSL_API_3_0)
#error "Multiple OPENSSL_API versions defined"
#endif
#if defined(OPENSSL_API_1_0) && defined(OPENSSL_API_3_0)
#error "Multiple OPENSSL_API versions defined"
#endif
#if (defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)                      \
     || defined(OPENSSL_API_3_0))                                              \
    && defined(USE_MBEDTLS)
#error "Multiple SSL libraries defined"
#endif
#endif
 
 
static pthread_key_t sTlsKey; /* Thread local storage index */
static volatile ptrdiff_t thread_idx_max = 0;
 
#if defined(MG_LEGACY_INTERFACE)
#define MG_ALLOW_USING_GET_REQUEST_INFO_FOR_RESPONSE
#endif
 
struct mg_workerTLS {
    int is_master;
    unsigned long thread_idx;
    void *user_ptr;
#if defined(_WIN32)
    HANDLE pthread_cond_helper_mutex;
    struct mg_workerTLS *next_waiting_thread;
#endif
    const char *alpn_proto;
#if defined(MG_ALLOW_USING_GET_REQUEST_INFO_FOR_RESPONSE)
    char txtbuf[4];
#endif
};
 
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-function"
#endif
 
 
/* Get a unique thread ID as unsigned long, independent from the data type
 * of thread IDs defined by the operating system API.
 * If two calls to mg_current_thread_id  return the same value, they calls
 * are done from the same thread. If they return different values, they are
 * done from different threads. (Provided this function is used in the same
 * process context and threads are not repeatedly created and deleted, but
 * CivetWeb does not do that).
 * This function must match the signature required for SSL id callbacks:
 * CRYPTO_set_id_callback
 */
FUNCTION_MAY_BE_UNUSED
static unsigned long
mg_current_thread_id(void)
{
#if defined(_WIN32)
    return GetCurrentThreadId();
#else
 
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code"
    /* For every compiler, either "sizeof(pthread_t) > sizeof(unsigned long)"
     * or not, so one of the two conditions will be unreachable by construction.
     * Unfortunately the C standard does not define a way to check this at
     * compile time, since the #if preprocessor conditions can not use the
     * sizeof operator as an argument. */
#endif
 
    if (sizeof(pthread_t) > sizeof(unsigned long)) {
        /* This is the problematic case for CRYPTO_set_id_callback:
         * The OS pthread_t can not be cast to unsigned long. */
        struct mg_workerTLS *tls =
            (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
        if (tls == NULL) {
            /* SSL called from an unknown thread: Create some thread index.
             */
            tls = (struct mg_workerTLS *)mg_malloc(sizeof(struct mg_workerTLS));
            tls->is_master = -2; /* -2 means "3rd party thread" */
            tls->thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
            pthread_setspecific(sTlsKey, tls);
        }
        return tls->thread_idx;
    } else {
        /* pthread_t may be any data type, so a simple cast to unsigned long
         * can rise a warning/error, depending on the platform.
         * Here memcpy is used as an anything-to-anything cast. */
        unsigned long ret = 0;
        pthread_t t = pthread_self();
        memcpy(&ret, &t, sizeof(pthread_t));
        return ret;
    }
 
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
 
#endif
}
 
 
FUNCTION_MAY_BE_UNUSED
static uint64_t
mg_get_current_time_ns(void)
{
    struct timespec tsnow;
    clock_gettime(CLOCK_REALTIME, &tsnow);
    return (((uint64_t)tsnow.tv_sec) * 1000000000) + (uint64_t)tsnow.tv_nsec;
}
 
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */
#if defined(__clang__)
/* Show no warning in case system functions are not used. */
#pragma clang diagnostic pop
#endif
 
 
#if defined(NEED_DEBUG_TRACE_FUNC)
static void
DEBUG_TRACE_FUNC(const char *func, unsigned line, const char *fmt, ...)
{
    va_list args;
    struct timespec tsnow;
 
    /* Get some operating system independent thread id */
    unsigned long thread_id = mg_current_thread_id();
 
    clock_gettime(CLOCK_REALTIME, &tsnow);
 
    flockfile(DEBUG_TRACE_STREAM);
    fprintf(DEBUG_TRACE_STREAM,
            "*** %lu.%09lu %lu %s:%u: ",
            (unsigned long)tsnow.tv_sec,
            (unsigned long)tsnow.tv_nsec,
            thread_id,
            func,
            line);
    va_start(args, fmt);
    vfprintf(DEBUG_TRACE_STREAM, fmt, args);
    va_end(args);
    putc('\n', DEBUG_TRACE_STREAM);
    fflush(DEBUG_TRACE_STREAM);
    funlockfile(DEBUG_TRACE_STREAM);
}
#endif /* NEED_DEBUG_TRACE_FUNC */
 
 
#define MD5_STATIC static
#include "md5.inl"
 
/* Darwin prior to 7.0 and Win32 do not have socklen_t */
#if defined(NO_SOCKLEN_T)
typedef int socklen_t;
#endif /* NO_SOCKLEN_T */
 
#define IP_ADDR_STR_LEN (50) /* IPv6 hex string is 46 chars */
 
#if !defined(MSG_NOSIGNAL)
#define MSG_NOSIGNAL (0)
#endif
 
 
/* SSL: mbedTLS vs. no-ssl vs. OpenSSL */
#if defined(USE_MBEDTLS)
/* mbedTLS */
#include "mod_mbedtls.inl"
 
#elif defined(NO_SSL)
/* no SSL */
typedef struct SSL SSL; /* dummy for SSL argument to push/pull */
typedef struct SSL_CTX SSL_CTX;
 
#elif defined(NO_SSL_DL)
/* OpenSSL without dynamic loading */
#include <openssl/bn.h>
#include <openssl/conf.h>
#include <openssl/crypto.h>
#include <openssl/dh.h>
#include <openssl/engine.h>
#include <openssl/err.h>
#include <openssl/opensslv.h>
#include <openssl/pem.h>
#include <openssl/ssl.h>
#include <openssl/tls1.h>
#include <openssl/x509.h>
 
#if defined(WOLFSSL_VERSION)
/* Additional defines for WolfSSL, see
 * https://github.com/civetweb/civetweb/issues/583 */
#include "wolfssl_extras.inl"
#endif
 
#if defined(OPENSSL_IS_BORINGSSL)
/* From boringssl/src/include/openssl/mem.h:
 *
 * OpenSSL has, historically, had a complex set of malloc debugging options.
 * However, that was written in a time before Valgrind and ASAN. Since we now
 * have those tools, the OpenSSL allocation functions are simply macros around
 * the standard memory functions.
 *
 * #define OPENSSL_free free */
#define free free
// disable for boringssl
#define CONF_modules_unload(a) ((void)0)
#define ENGINE_cleanup() ((void)0)
#endif
 
/* If OpenSSL headers are included, automatically select the API version */
#if (OPENSSL_VERSION_NUMBER >= 0x30000000L)
#if !defined(OPENSSL_API_3_0)
#define OPENSSL_API_3_0
#endif
#define OPENSSL_REMOVE_THREAD_STATE()
#else
#if (OPENSSL_VERSION_NUMBER >= 0x10100000L)
#if !defined(OPENSSL_API_1_1)
#define OPENSSL_API_1_1
#endif
#define OPENSSL_REMOVE_THREAD_STATE()
#else
#if !defined(OPENSSL_API_1_0)
#define OPENSSL_API_1_0
#endif
#define OPENSSL_REMOVE_THREAD_STATE() ERR_remove_thread_state(NULL)
#endif
#endif
 
 
#else
/* SSL loaded dynamically from DLL / shared object */
/* Add all prototypes here, to be independent from OpenSSL source
 * installation. */
#include "openssl_dl.inl"
 
#endif /* Various SSL bindings */
 
 
#if !defined(NO_CACHING)
static const char month_names[][4] = {"Jan",
                                      "Feb",
                                      "Mar",
                                      "Apr",
                                      "May",
                                      "Jun",
                                      "Jul",
                                      "Aug",
                                      "Sep",
                                      "Oct",
                                      "Nov",
                                      "Dec"};
#endif /* !NO_CACHING */
 
 
/* Unified socket address. For IPv6 support, add IPv6 address structure in
 * the union u. */
union usa {
    struct sockaddr sa;
    struct sockaddr_in sin;
#if defined(USE_IPV6)
    struct sockaddr_in6 sin6;
#endif
#if defined(USE_X_DOM_SOCKET)
    struct sockaddr_un sun;
#endif
};
 
#if defined(USE_X_DOM_SOCKET)
static unsigned short
USA_IN_PORT_UNSAFE(union usa *s)
{
    if (s->sa.sa_family == AF_INET)
        return s->sin.sin_port;
#if defined(USE_IPV6)
    if (s->sa.sa_family == AF_INET6)
        return s->sin6.sin6_port;
#endif
    return 0;
}
#endif
#if defined(USE_IPV6)
#define USA_IN_PORT_UNSAFE(s)                                                  \
    (((s)->sa.sa_family == AF_INET6) ? (s)->sin6.sin6_port : (s)->sin.sin_port)
#else
#define USA_IN_PORT_UNSAFE(s) ((s)->sin.sin_port)
#endif
 
/* Describes a string (chunk of memory). */
struct vec {
    const char *ptr;
    size_t len;
};
 
struct mg_file_stat {
    /* File properties filled by mg_stat: */
    uint64_t size;
    time_t last_modified;
    int is_directory; /* Set to 1 if mg_stat is called for a directory */
    int is_gzipped;   /* Set to 1 if the content is gzipped, in which
                       * case we need a "Content-Eencoding: gzip" header */
    int location;     /* 0 = nowhere, 1 = on disk, 2 = in memory */
};
 
 
struct mg_file_access {
    /* File properties filled by mg_fopen: */
    FILE *fp;
};
 
struct mg_file {
    struct mg_file_stat stat;
    struct mg_file_access access;
};
 
 
#define STRUCT_FILE_INITIALIZER                                                \
    {                                                                          \
        {(uint64_t)0, (time_t)0, 0, 0, 0},                                     \
        {                                                                      \
            (FILE *)NULL                                                       \
        }                                                                      \
    }
 
 
/* Describes listening socket, or socket which was accept()-ed by the master
 * thread and queued for future handling by the worker thread. */
struct socket {
    SOCKET sock;             /* Listening socket */
    union usa lsa;           /* Local socket address */
    union usa rsa;           /* Remote socket address */
    unsigned char is_ssl;    /* Is port SSL-ed */
    unsigned char ssl_redir; /* Is port supposed to redirect everything to SSL
                              * port */
    unsigned char in_use;    /* 0: invalid, 1: valid, 2: free */
};
 
 
/* Enum const for all options must be in sync with
 * static struct mg_option config_options[]
 * This is tested in the unit test (test/private.c)
 * "Private Config Options"
 */
enum {
    /* Once for each server */
    LISTENING_PORTS,
    NUM_THREADS,
    RUN_AS_USER,
    CONFIG_TCP_NODELAY, /* Prepended CONFIG_ to avoid conflict with the
                         * socket option typedef TCP_NODELAY. */
    MAX_REQUEST_SIZE,
    LINGER_TIMEOUT,
    CONNECTION_QUEUE_SIZE,
    LISTEN_BACKLOG_SIZE,
#if defined(__linux__)
    ALLOW_SENDFILE_CALL,
#endif
#if defined(_WIN32)
    CASE_SENSITIVE_FILES,
#endif
    THROTTLE,
    ENABLE_KEEP_ALIVE,
    REQUEST_TIMEOUT,
    KEEP_ALIVE_TIMEOUT,
#if defined(USE_WEBSOCKET)
    WEBSOCKET_TIMEOUT,
    ENABLE_WEBSOCKET_PING_PONG,
#endif
    DECODE_URL,
    DECODE_QUERY_STRING,
#if defined(USE_LUA)
    LUA_BACKGROUND_SCRIPT,
    LUA_BACKGROUND_SCRIPT_PARAMS,
#endif
#if defined(USE_HTTP2)
    ENABLE_HTTP2,
#endif
 
    /* Once for each domain */
    DOCUMENT_ROOT,
 
    ACCESS_LOG_FILE,
    ERROR_LOG_FILE,
 
    CGI_EXTENSIONS,
    CGI_ENVIRONMENT,
    CGI_INTERPRETER,
    CGI_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
    CGI_TIMEOUT,
#endif
    CGI_BUFFERING,
 
    CGI2_EXTENSIONS,
    CGI2_ENVIRONMENT,
    CGI2_INTERPRETER,
    CGI2_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
    CGI2_TIMEOUT,
#endif
    CGI2_BUFFERING,
 
#if defined(USE_4_CGI)
    CGI3_EXTENSIONS,
    CGI3_ENVIRONMENT,
    CGI3_INTERPRETER,
    CGI3_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
    CGI3_TIMEOUT,
#endif
    CGI3_BUFFERING,
 
    CGI4_EXTENSIONS,
    CGI4_ENVIRONMENT,
    CGI4_INTERPRETER,
    CGI4_INTERPRETER_ARGS,
#if defined(USE_TIMERS)
    CGI4_TIMEOUT,
#endif
    CGI4_BUFFERING,
#endif
 
    PUT_DELETE_PASSWORDS_FILE, /* must follow CGI_* */
    PROTECT_URI,
    AUTHENTICATION_DOMAIN,
    ENABLE_AUTH_DOMAIN_CHECK,
    SSI_EXTENSIONS,
    ENABLE_DIRECTORY_LISTING,
    ENABLE_WEBDAV,
    GLOBAL_PASSWORDS_FILE,
    INDEX_FILES,
    ACCESS_CONTROL_LIST,
    EXTRA_MIME_TYPES,
    SSL_CERTIFICATE,
    SSL_CERTIFICATE_CHAIN,
    URL_REWRITE_PATTERN,
    HIDE_FILES,
    SSL_DO_VERIFY_PEER,
    SSL_CACHE_TIMEOUT,
    SSL_CA_PATH,
    SSL_CA_FILE,
    SSL_VERIFY_DEPTH,
    SSL_DEFAULT_VERIFY_PATHS,
    SSL_CIPHER_LIST,
    SSL_PROTOCOL_VERSION,
    SSL_SHORT_TRUST,
 
#if defined(USE_LUA)
    LUA_PRELOAD_FILE,
    LUA_SCRIPT_EXTENSIONS,
    LUA_SERVER_PAGE_EXTENSIONS,
#if defined(MG_EXPERIMENTAL_INTERFACES)
    LUA_DEBUG_PARAMS,
#endif
#endif
#if defined(USE_DUKTAPE)
    DUKTAPE_SCRIPT_EXTENSIONS,
#endif
 
#if defined(USE_WEBSOCKET)
    WEBSOCKET_ROOT,
#endif
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
    LUA_WEBSOCKET_EXTENSIONS,
#endif
 
    ACCESS_CONTROL_ALLOW_ORIGIN,
    ACCESS_CONTROL_ALLOW_METHODS,
    ACCESS_CONTROL_ALLOW_HEADERS,
    ERROR_PAGES,
#if !defined(NO_CACHING)
    STATIC_FILE_MAX_AGE,
    STATIC_FILE_CACHE_CONTROL,
#endif
#if !defined(NO_SSL)
    STRICT_HTTPS_MAX_AGE,
#endif
    ADDITIONAL_HEADER,
    ALLOW_INDEX_SCRIPT_SUB_RES,
 
    NUM_OPTIONS
};
 
 
/* Config option name, config types, default value.
 * Must be in the same order as the enum const above.
 */
static const struct mg_option config_options[] = {
 
    /* Once for each server */
    {"listening_ports", MG_CONFIG_TYPE_STRING_LIST, "8080"},
    {"num_threads", MG_CONFIG_TYPE_NUMBER, "50"},
    {"run_as_user", MG_CONFIG_TYPE_STRING, NULL},
    {"tcp_nodelay", MG_CONFIG_TYPE_NUMBER, "0"},
    {"max_request_size", MG_CONFIG_TYPE_NUMBER, "16384"},
    {"linger_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
    {"connection_queue", MG_CONFIG_TYPE_NUMBER, "20"},
    {"listen_backlog", MG_CONFIG_TYPE_NUMBER, "200"},
#if defined(__linux__)
    {"allow_sendfile_call", MG_CONFIG_TYPE_BOOLEAN, "yes"},
#endif
#if defined(_WIN32)
    {"case_sensitive", MG_CONFIG_TYPE_BOOLEAN, "no"},
#endif
    {"throttle", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"enable_keep_alive", MG_CONFIG_TYPE_BOOLEAN, "no"},
    {"request_timeout_ms", MG_CONFIG_TYPE_NUMBER, "30000"},
    {"keep_alive_timeout_ms", MG_CONFIG_TYPE_NUMBER, "500"},
#if defined(USE_WEBSOCKET)
    {"websocket_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
    {"enable_websocket_ping_pong", MG_CONFIG_TYPE_BOOLEAN, "no"},
#endif
    {"decode_url", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"decode_query_string", MG_CONFIG_TYPE_BOOLEAN, "no"},
#if defined(USE_LUA)
    {"lua_background_script", MG_CONFIG_TYPE_FILE, NULL},
    {"lua_background_script_params", MG_CONFIG_TYPE_STRING_LIST, NULL},
#endif
#if defined(USE_HTTP2)
    {"enable_http2", MG_CONFIG_TYPE_BOOLEAN, "no"},
#endif
 
    /* Once for each domain */
    {"document_root", MG_CONFIG_TYPE_DIRECTORY, NULL},
 
    {"access_log_file", MG_CONFIG_TYPE_FILE, NULL},
    {"error_log_file", MG_CONFIG_TYPE_FILE, NULL},
 
    {"cgi_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.cgi$|**.pl$|**.php$"},
    {"cgi_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},
 
    {"cgi2_pattern", MG_CONFIG_TYPE_EXT_PATTERN, NULL},
    {"cgi2_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi2_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi2_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi2_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi2_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},
 
#if defined(USE_4_CGI)
    {"cgi3_pattern", MG_CONFIG_TYPE_EXT_PATTERN, NULL},
    {"cgi3_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi3_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi3_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi3_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi3_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},
 
    {"cgi4_pattern", MG_CONFIG_TYPE_EXT_PATTERN, NULL},
    {"cgi4_environment", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"cgi4_interpreter", MG_CONFIG_TYPE_FILE, NULL},
    {"cgi4_interpreter_args", MG_CONFIG_TYPE_STRING, NULL},
#if defined(USE_TIMERS)
    {"cgi4_timeout_ms", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"cgi4_buffering", MG_CONFIG_TYPE_BOOLEAN, "yes"},
 
#endif
 
    {"put_delete_auth_file", MG_CONFIG_TYPE_FILE, NULL},
    {"protect_uri", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"authentication_domain", MG_CONFIG_TYPE_STRING, "mydomain.com"},
    {"enable_auth_domain_check", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"ssi_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.shtml$|**.shtm$"},
    {"enable_directory_listing", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"enable_webdav", MG_CONFIG_TYPE_BOOLEAN, "no"},
    {"global_auth_file", MG_CONFIG_TYPE_FILE, NULL},
    {"index_files",
     MG_CONFIG_TYPE_STRING_LIST,
#if defined(USE_LUA)
     "index.xhtml,index.html,index.htm,"
     "index.lp,index.lsp,index.lua,index.cgi,"
     "index.shtml,index.php"},
#else
     "index.xhtml,index.html,index.htm,index.cgi,index.shtml,index.php"},
#endif
    {"access_control_list", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"extra_mime_types", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"ssl_certificate", MG_CONFIG_TYPE_FILE, NULL},
    {"ssl_certificate_chain", MG_CONFIG_TYPE_FILE, NULL},
    {"url_rewrite_patterns", MG_CONFIG_TYPE_STRING_LIST, NULL},
    {"hide_files_patterns", MG_CONFIG_TYPE_EXT_PATTERN, NULL},
 
    {"ssl_verify_peer", MG_CONFIG_TYPE_YES_NO_OPTIONAL, "no"},
    {"ssl_cache_timeout", MG_CONFIG_TYPE_NUMBER, "-1"},
 
    {"ssl_ca_path", MG_CONFIG_TYPE_DIRECTORY, NULL},
    {"ssl_ca_file", MG_CONFIG_TYPE_FILE, NULL},
    {"ssl_verify_depth", MG_CONFIG_TYPE_NUMBER, "9"},
    {"ssl_default_verify_paths", MG_CONFIG_TYPE_BOOLEAN, "yes"},
    {"ssl_cipher_list", MG_CONFIG_TYPE_STRING, NULL},
 
    /* HTTP2 requires ALPN, and anyway TLS1.2 should be considered
     * as a minimum in 2020 */
    {"ssl_protocol_version", MG_CONFIG_TYPE_NUMBER, "4"},
 
    {"ssl_short_trust", MG_CONFIG_TYPE_BOOLEAN, "no"},
 
#if defined(USE_LUA)
    {"lua_preload_file", MG_CONFIG_TYPE_FILE, NULL},
    {"lua_script_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.lua$"},
    {"lua_server_page_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.lp$|**.lsp$"},
#if defined(MG_EXPERIMENTAL_INTERFACES)
    {"lua_debug", MG_CONFIG_TYPE_STRING, NULL},
#endif
#endif
#if defined(USE_DUKTAPE)
    /* The support for duktape is still in alpha version state.
     * The name of this config option might change. */
    {"duktape_script_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.ssjs$"},
#endif
 
#if defined(USE_WEBSOCKET)
    {"websocket_root", MG_CONFIG_TYPE_DIRECTORY, NULL},
#endif
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
    {"lua_websocket_pattern", MG_CONFIG_TYPE_EXT_PATTERN, "**.lua$"},
#endif
    {"access_control_allow_origin", MG_CONFIG_TYPE_STRING, "*"},
    {"access_control_allow_methods", MG_CONFIG_TYPE_STRING, "*"},
    {"access_control_allow_headers", MG_CONFIG_TYPE_STRING, "*"},
    {"error_pages", MG_CONFIG_TYPE_DIRECTORY, NULL},
#if !defined(NO_CACHING)
    {"static_file_max_age", MG_CONFIG_TYPE_NUMBER, "3600"},
    {"static_file_cache_control", MG_CONFIG_TYPE_STRING, NULL},
#endif
#if !defined(NO_SSL)
    {"strict_transport_security_max_age", MG_CONFIG_TYPE_NUMBER, NULL},
#endif
    {"additional_header", MG_CONFIG_TYPE_STRING_MULTILINE, NULL},
    {"allow_index_script_resource", MG_CONFIG_TYPE_BOOLEAN, "no"},
 
    {NULL, MG_CONFIG_TYPE_UNKNOWN, NULL}};
 
 
/* Check if the config_options and the corresponding enum have compatible
 * sizes. */
mg_static_assert((sizeof(config_options) / sizeof(config_options[0]))
                     == (NUM_OPTIONS + 1),
                 "config_options and enum not sync");
 
 
enum { REQUEST_HANDLER, WEBSOCKET_HANDLER, AUTH_HANDLER };
 
 
struct mg_handler_info {
    /* Name/Pattern of the URI. */
    char *uri;
    size_t uri_len;
 
    /* handler type */
    int handler_type;
 
    /* Handler for http/https or requests. */
    mg_request_handler handler;
    unsigned int refcount;
    int removing;
 
    /* Handler for ws/wss (websocket) requests. */
    mg_websocket_connect_handler connect_handler;
    mg_websocket_ready_handler ready_handler;
    mg_websocket_data_handler data_handler;
    mg_websocket_close_handler close_handler;
 
    /* accepted subprotocols for ws/wss requests. */
    struct mg_websocket_subprotocols *subprotocols;
 
    /* Handler for authorization requests */
    mg_authorization_handler auth_handler;
 
    /* User supplied argument for the handler function. */
    void *cbdata;
 
    /* next handler in a linked list */
    struct mg_handler_info *next;
};
 
 
enum {
    CONTEXT_INVALID,
    CONTEXT_SERVER,
    CONTEXT_HTTP_CLIENT,
    CONTEXT_WS_CLIENT
};
 
 
struct mg_domain_context {
    SSL_CTX *ssl_ctx;                 /* SSL context */
    char *config[NUM_OPTIONS];        /* Civetweb configuration parameters */
    struct mg_handler_info *handlers; /* linked list of uri handlers */
    int64_t ssl_cert_last_mtime;
 
    /* Server nonce */
    uint64_t auth_nonce_mask;  /* Mask for all nonce values */
    unsigned long nonce_count; /* Used nonces, used for authentication */
 
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
    /* linked list of shared lua websockets */
    struct mg_shared_lua_websocket_list *shared_lua_websockets;
#endif
 
    /* Linked list of domains */
    struct mg_domain_context *next;
};
 
 
/* Stop flag can be "volatile" or require a lock.
 * MSDN uses volatile for "Interlocked" operations, but also explicitly
 * states a read operation for int is always atomic. */
#if defined(STOP_FLAG_NEEDS_LOCK)
 
typedef ptrdiff_t volatile stop_flag_t;
 
static int
STOP_FLAG_IS_ZERO(const stop_flag_t *f)
{
    stop_flag_t sf = mg_atomic_add((stop_flag_t *)f, 0);
    return (sf == 0);
}
 
static int
STOP_FLAG_IS_TWO(stop_flag_t *f)
{
    stop_flag_t sf = mg_atomic_add(f, 0);
    return (sf == 2);
}
 
static void
STOP_FLAG_ASSIGN(stop_flag_t *f, stop_flag_t v)
{
    stop_flag_t sf;
    do {
        sf = mg_atomic_compare_and_swap(f, *f, v);
    } while (sf != v);
}
 
#else /* STOP_FLAG_NEEDS_LOCK */
 
typedef int volatile stop_flag_t;
#define STOP_FLAG_IS_ZERO(f) ((*(f)) == 0)
#define STOP_FLAG_IS_TWO(f) ((*(f)) == 2)
#define STOP_FLAG_ASSIGN(f, v) ((*(f)) = (v))
 
#endif /* STOP_FLAG_NEEDS_LOCK */
 
 
#if !defined(NUM_WEBDAV_LOCKS)
#define NUM_WEBDAV_LOCKS 10
#endif
#if !defined(LOCK_DURATION_S)
#define LOCK_DURATION_S 60
#endif
 
 
struct twebdav_lock {
    uint64_t locktime;
    char token[33];
    char path[UTF8_PATH_MAX * 2];
    char user[UTF8_PATH_MAX * 2];
};
 
 
struct mg_context {
 
    /* Part 1 - Physical context:
     * This holds threads, ports, timeouts, ...
     * set for the entire server, independent from the
     * addressed hostname.
     */
 
    /* Connection related */
    int context_type; /* See CONTEXT_* above */
 
    struct socket *listening_sockets;
    struct mg_pollfd *listening_socket_fds;
    unsigned int num_listening_sockets;
 
    struct mg_connection *worker_connections; /* The connection struct, pre-
                                               * allocated for each worker */
 
#if defined(USE_SERVER_STATS)
    volatile ptrdiff_t active_connections;
    volatile ptrdiff_t max_active_connections;
    volatile ptrdiff_t total_connections;
    volatile ptrdiff_t total_requests;
    volatile int64_t total_data_read;
    volatile int64_t total_data_written;
#endif
 
    /* Thread related */
    stop_flag_t stop_flag;        /* Should we stop event loop */
    pthread_mutex_t thread_mutex; /* Protects client_socks or queue */
 
    pthread_t masterthreadid; /* The master thread ID */
    unsigned int
        cfg_worker_threads;      /* The number of configured worker threads. */
    pthread_t *worker_threadids; /* The worker thread IDs */
    unsigned long starter_thread_idx; /* thread index which called mg_start */
 
    /* Connection to thread dispatching */
#if defined(ALTERNATIVE_QUEUE)
    struct socket *client_socks;
    void **client_wait_events;
#else
    struct socket *squeue; /* Socket queue (sq) : accepted sockets waiting for a
                           worker thread */
    volatile int sq_head;  /* Head of the socket queue */
    volatile int sq_tail;  /* Tail of the socket queue */
    pthread_cond_t sq_full;  /* Signaled when socket is produced */
    pthread_cond_t sq_empty; /* Signaled when socket is consumed */
    volatile int sq_blocked; /* Status information: sq is full */
    int sq_size;             /* No of elements in socket queue */
#if defined(USE_SERVER_STATS)
    int sq_max_fill;
#endif /* USE_SERVER_STATS */
#endif /* ALTERNATIVE_QUEUE */
 
    /* Memory related */
    unsigned int max_request_size; /* The max request size */
 
#if defined(USE_SERVER_STATS)
    struct mg_memory_stat ctx_memory;
#endif
 
    /* WebDAV lock structures */
    struct twebdav_lock webdav_lock[NUM_WEBDAV_LOCKS];
 
    /* Operating system related */
    char *systemName;  /* What operating system is running */
    time_t start_time; /* Server start time, used for authentication
                        * and for diagnstics. */
 
#if defined(USE_TIMERS)
    struct ttimers *timers;
#endif
 
    /* Lua specific: Background operations and shared websockets */
#if defined(USE_LUA)
    void *lua_background_state;   /* lua_State (here as void *) */
    pthread_mutex_t lua_bg_mutex; /* Protect background state */
    int lua_bg_log_available;     /* Use Lua background state for access log */
#endif
 
    /* Server nonce */
    pthread_mutex_t nonce_mutex; /* Protects ssl_ctx, handlers,
                                  * ssl_cert_last_mtime, nonce_count, and
                                  * next (linked list) */
 
    /* Server callbacks */
    struct mg_callbacks callbacks; /* User-defined callback function */
    void *user_data;               /* User-defined data */
 
    /* Part 2 - Logical domain:
     * This holds hostname, TLS certificate, document root, ...
     * set for a domain hosted at the server.
     * There may be multiple domains hosted at one physical server.
     * The default domain "dd" is the first element of a list of
     * domains.
     */
    struct mg_domain_context dd; /* default domain */
};
 
 
#if defined(USE_SERVER_STATS)
static struct mg_memory_stat mg_common_memory = {0, 0, 0};
 
static struct mg_memory_stat *
get_memory_stat(struct mg_context *ctx)
{
    if (ctx) {
        return &(ctx->ctx_memory);
    }
    return &mg_common_memory;
}
#endif
 
enum {
    CONNECTION_TYPE_INVALID = 0,
    CONNECTION_TYPE_REQUEST = 1,
    CONNECTION_TYPE_RESPONSE = 2
};
 
enum {
    PROTOCOL_TYPE_HTTP1 = 0,
    PROTOCOL_TYPE_WEBSOCKET = 1,
    PROTOCOL_TYPE_HTTP2 = 2
};
 
 
#if defined(USE_HTTP2)
#if !defined(HTTP2_DYN_TABLE_SIZE)
#define HTTP2_DYN_TABLE_SIZE (256)
#endif
 
struct mg_http2_connection {
    uint32_t stream_id;
    uint32_t dyn_table_size;
    struct mg_header dyn_table[HTTP2_DYN_TABLE_SIZE];
};
#endif
 
 
struct mg_connection {
    int connection_type; /* see CONNECTION_TYPE_* above */
    int protocol_type;   /* see PROTOCOL_TYPE_*: 0=http/1.x, 1=ws, 2=http/2 */
    int request_state;   /* 0: nothing sent, 1: header partially sent, 2: header
                         fully sent */
#if defined(USE_HTTP2)
    struct mg_http2_connection http2;
#endif
 
    struct mg_request_info request_info;
    struct mg_response_info response_info;
 
    struct mg_context *phys_ctx;
    struct mg_domain_context *dom_ctx;
 
#if defined(USE_SERVER_STATS)
    int conn_state; /* 0 = undef, numerical value may change in different
                     * versions. For the current definition, see
                     * mg_get_connection_info_impl */
#endif
 
    SSL *ssl;               /* SSL descriptor */
    struct socket client;   /* Connected client */
    time_t conn_birth_time; /* Time (wall clock) when connection was
                             * established */
#if defined(USE_SERVER_STATS)
    time_t conn_close_time; /* Time (wall clock) when connection was
                             * closed (or 0 if still open) */
    double processing_time; /* Processing time for one request. */
#endif
    struct timespec req_time; /* Time (since system start) when the request
                               * was received */
    int64_t num_bytes_sent;   /* Total bytes sent to client */
    int64_t content_len;      /* How many bytes of content can be read
                               * !is_chunked: Content-Length header value
                               *              or -1 (until connection closed,
                               *                     not allowed for a request)
                               * is_chunked: >= 0, appended gradually
                               */
    int64_t consumed_content; /* How many bytes of content have been read */
    int is_chunked;           /* Transfer-Encoding is chunked:
                               * 0 = not chunked,
                               * 1 = chunked, not yet, or some data read,
                               * 2 = chunked, has error,
                               * 3 = chunked, all data read except trailer,
                               * 4 = chunked, all data read
                               */
    char *buf;                /* Buffer for received data */
    char *path_info;          /* PATH_INFO part of the URL */
 
    int must_close;       /* 1 if connection must be closed */
    int accept_gzip;      /* 1 if gzip encoding is accepted */
    int in_error_handler; /* 1 if in handler for user defined error
                           * pages */
#if defined(USE_WEBSOCKET)
    int in_websocket_handling; /* 1 if in read_websocket */
#endif
#if defined(USE_ZLIB) && defined(USE_WEBSOCKET)                                \
    && defined(MG_EXPERIMENTAL_INTERFACES)
    /* Parameters for websocket data compression according to rfc7692 */
    int websocket_deflate_server_max_windows_bits;
    int websocket_deflate_client_max_windows_bits;
    int websocket_deflate_server_no_context_takeover;
    int websocket_deflate_client_no_context_takeover;
    int websocket_deflate_initialized;
    int websocket_deflate_flush;
    z_stream websocket_deflate_state;
    z_stream websocket_inflate_state;
#endif
    int handled_requests; /* Number of requests handled by this connection
                           */
    int buf_size;         /* Buffer size */
    int request_len;      /* Size of the request + headers in a buffer */
    int data_len;         /* Total size of data in a buffer */
    int status_code;      /* HTTP reply status code, e.g. 200 */
    int throttle;         /* Throttling, bytes/sec. <= 0 means no
                           * throttle */
 
    time_t last_throttle_time; /* Last time throttled data was sent */
    int last_throttle_bytes;   /* Bytes sent this second */
    pthread_mutex_t mutex;     /* Used by mg_(un)lock_connection to ensure
                                * atomic transmissions for websockets */
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
    void *lua_websocket_state; /* Lua_State for a websocket connection */
#endif
 
    void *tls_user_ptr; /* User defined pointer in thread local storage,
                         * for quick access */
};
 
 
/* Directory entry */
struct de {
    char *file_name;
    struct mg_file_stat file;
};
 
 
#define mg_cry_internal(conn, fmt, ...)                                        \
    mg_cry_internal_wrap(conn, NULL, __func__, __LINE__, fmt, __VA_ARGS__)
 
#define mg_cry_ctx_internal(ctx, fmt, ...)                                     \
    mg_cry_internal_wrap(NULL, ctx, __func__, __LINE__, fmt, __VA_ARGS__)
 
static void mg_cry_internal_wrap(const struct mg_connection *conn,
                                 struct mg_context *ctx,
                                 const char *func,
                                 unsigned line,
                                 const char *fmt,
                                 ...) PRINTF_ARGS(5, 6);
 
 
#if !defined(NO_THREAD_NAME)
#if defined(_WIN32) && defined(_MSC_VER)
/* Set the thread name for debugging purposes in Visual Studio
 * http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx
 */
#pragma pack(push, 8)
typedef struct tagTHREADNAME_INFO {
    DWORD dwType;     /* Must be 0x1000. */
    LPCSTR szName;    /* Pointer to name (in user addr space). */
    DWORD dwThreadID; /* Thread ID (-1=caller thread). */
    DWORD dwFlags;    /* Reserved for future use, must be zero. */
} THREADNAME_INFO;
#pragma pack(pop)
 
#elif defined(__linux__)
 
#include <sys/prctl.h>
#include <sys/sendfile.h>
#if defined(ALTERNATIVE_QUEUE)
#include <sys/eventfd.h>
#endif /* ALTERNATIVE_QUEUE */
 
 
#if defined(ALTERNATIVE_QUEUE)
 
static void *
event_create(void)
{
    int evhdl = eventfd(0, EFD_CLOEXEC);
    int *ret;
 
    if (evhdl == -1) {
        /* Linux uses -1 on error, Windows NULL. */
        /* However, Linux does not return 0 on success either. */
        return 0;
    }
 
    ret = (int *)mg_malloc(sizeof(int));
    if (ret) {
        *ret = evhdl;
    } else {
        (void)close(evhdl);
    }
 
    return (void *)ret;
}
 
 
static int
event_wait(void *eventhdl)
{
    uint64_t u;
    int evhdl, s;
 
    if (!eventhdl) {
        /* error */
        return 0;
    }
    evhdl = *(int *)eventhdl;
 
    s = (int)read(evhdl, &u, sizeof(u));
    if (s != sizeof(u)) {
        /* error */
        return 0;
    }
    (void)u; /* the value is not required */
    return 1;
}
 
 
static int
event_signal(void *eventhdl)
{
    uint64_t u = 1;
    int evhdl, s;
 
    if (!eventhdl) {
        /* error */
        return 0;
    }
    evhdl = *(int *)eventhdl;
 
    s = (int)write(evhdl, &u, sizeof(u));
    if (s != sizeof(u)) {
        /* error */
        return 0;
    }
    return 1;
}
 
 
static void
event_destroy(void *eventhdl)
{
    int evhdl;
 
    if (!eventhdl) {
        /* error */
        return;
    }
    evhdl = *(int *)eventhdl;
 
    close(evhdl);
    mg_free(eventhdl);
}
 
 
#endif
 
#endif
 
 
#if !defined(__linux__) && !defined(_WIN32) && defined(ALTERNATIVE_QUEUE)
 
struct posix_event {
    pthread_mutex_t mutex;
    pthread_cond_t cond;
    int signaled;
};
 
 
static void *
event_create(void)
{
    struct posix_event *ret = mg_malloc(sizeof(struct posix_event));
    if (ret == 0) {
        /* out of memory */
        return 0;
    }
    if (0 != pthread_mutex_init(&(ret->mutex), NULL)) {
        /* pthread mutex not available */
        mg_free(ret);
        return 0;
    }
    if (0 != pthread_cond_init(&(ret->cond), NULL)) {
        /* pthread cond not available */
        pthread_mutex_destroy(&(ret->mutex));
        mg_free(ret);
        return 0;
    }
    ret->signaled = 0;
    return (void *)ret;
}
 
 
static int
event_wait(void *eventhdl)
{
    struct posix_event *ev = (struct posix_event *)eventhdl;
    pthread_mutex_lock(&(ev->mutex));
    while (!ev->signaled) {
        pthread_cond_wait(&(ev->cond), &(ev->mutex));
    }
    ev->signaled = 0;
    pthread_mutex_unlock(&(ev->mutex));
    return 1;
}
 
 
static int
event_signal(void *eventhdl)
{
    struct posix_event *ev = (struct posix_event *)eventhdl;
    pthread_mutex_lock(&(ev->mutex));
    pthread_cond_signal(&(ev->cond));
    ev->signaled = 1;
    pthread_mutex_unlock(&(ev->mutex));
    return 1;
}
 
 
static void
event_destroy(void *eventhdl)
{
    struct posix_event *ev = (struct posix_event *)eventhdl;
    pthread_cond_destroy(&(ev->cond));
    pthread_mutex_destroy(&(ev->mutex));
    mg_free(ev);
}
#endif
 
 
static void
mg_set_thread_name(const char *name)
{
    char threadName[16 + 1]; /* 16 = Max. thread length in Linux/OSX/.. */
 
    mg_snprintf(
        NULL, NULL, threadName, sizeof(threadName), "civetweb-%s", name);
 
#if defined(_WIN32)
#if defined(_MSC_VER)
    /* Windows and Visual Studio Compiler */
    __try {
        THREADNAME_INFO info;
        info.dwType = 0x1000;
        info.szName = threadName;
        info.dwThreadID = ~0U;
        info.dwFlags = 0;
 
        RaiseException(0x406D1388,
                       0,
                       sizeof(info) / sizeof(ULONG_PTR),
                       (ULONG_PTR *)&info);
    } __except (EXCEPTION_EXECUTE_HANDLER) {
    }
#elif defined(__MINGW32__)
    /* No option known to set thread name for MinGW known */
#endif
#elif defined(_GNU_SOURCE) && defined(__GLIBC__)                               \
    && ((__GLIBC__ > 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 12)))
    /* pthread_setname_np first appeared in glibc in version 2.12 */
#if defined(__MACH__) && defined(__APPLE__)
    /* OS X only current thread name can be changed */
    (void)pthread_setname_np(threadName);
#else
    (void)pthread_setname_np(pthread_self(), threadName);
#endif
#elif defined(__linux__)
    /* On Linux we can use the prctl function.
     * When building for Linux Standard Base (LSB) use
     * NO_THREAD_NAME. However, thread names are a big
     * help for debugging, so the stadard is to set them.
     */
    (void)prctl(PR_SET_NAME, threadName, 0, 0, 0);
#endif
}
#else /* !defined(NO_THREAD_NAME) */
static void
mg_set_thread_name(const char *threadName)
{
}
#endif
 
 
CIVETWEB_API const struct mg_option *
mg_get_valid_options(void)
{
    return config_options;
}
 
 
/* Do not open file (unused) */
#define MG_FOPEN_MODE_NONE (0)
 
/* Open file for read only access */
#define MG_FOPEN_MODE_READ (1)
 
/* Open file for writing, create and overwrite */
#define MG_FOPEN_MODE_WRITE (2)
 
/* Open file for writing, create and append */
#define MG_FOPEN_MODE_APPEND (4)
 
 
static int
is_file_opened(const struct mg_file_access *fileacc)
{
    if (!fileacc) {
        return 0;
    }
 
    return (fileacc->fp != NULL);
}
 
 
#if !defined(NO_FILESYSTEMS)
static int mg_stat(const struct mg_connection *conn,
                   const char *path,
                   struct mg_file_stat *filep);
 
 
/* Reject files with special characters (for Windows) */
static int
mg_path_suspicious(const struct mg_connection *conn, const char *path)
{
    const uint8_t *c = (const uint8_t *)path;
    (void)conn; /* not used */
 
    if ((c == NULL) || (c[0] == 0)) {
        /* Null pointer or empty path --> suspicious */
        return 1;
    }
 
#if defined(_WIN32)
    while (*c) {
        if (*c < 32) {
            /* Control character */
            return 1;
        }
        if ((*c == '>') || (*c == '<') || (*c == '|')) {
            /* stdin/stdout redirection character */
            return 1;
        }
        if ((*c == '*') || (*c == '?')) {
            /* Wildcard character */
            return 1;
        }
        if (*c == '"') {
            /* Windows quotation */
            return 1;
        }
        c++;
    }
#endif
 
    /* Nothing suspicious found */
    return 0;
}
 
 
/* mg_fopen will open a file either in memory or on the disk.
 * The input parameter path is a string in UTF-8 encoding.
 * The input parameter mode is MG_FOPEN_MODE_*
 * On success, fp will be set in the output struct mg_file.
 * All status members will also be set.
 * The function returns 1 on success, 0 on error. */
static int
mg_fopen(const struct mg_connection *conn,
         const char *path,
         int mode,
         struct mg_file *filep)
{
    int found;
 
    if (!filep) {
        return 0;
    }
    filep->access.fp = NULL;
 
    if (mg_path_suspicious(conn, path)) {
        return 0;
    }
 
    /* filep is initialized in mg_stat: all fields with memset to,
     * some fields like size and modification date with values */
    found = mg_stat(conn, path, &(filep->stat));
 
    if ((mode == MG_FOPEN_MODE_READ) && (!found)) {
        /* file does not exist and will not be created */
        return 0;
    }
 
#if defined(_WIN32)
    {
        wchar_t wbuf[UTF16_PATH_MAX];
        path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
        switch (mode) {
        case MG_FOPEN_MODE_READ:
            filep->access.fp = _wfopen(wbuf, L"rb");
            break;
        case MG_FOPEN_MODE_WRITE:
            filep->access.fp = _wfopen(wbuf, L"wb");
            break;
        case MG_FOPEN_MODE_APPEND:
            filep->access.fp = _wfopen(wbuf, L"ab");
            break;
        }
    }
#else
    /* Linux et al already use unicode. No need to convert. */
    switch (mode) {
    case MG_FOPEN_MODE_READ:
        filep->access.fp = fopen(path, "r");
        break;
    case MG_FOPEN_MODE_WRITE:
        filep->access.fp = fopen(path, "w");
        break;
    case MG_FOPEN_MODE_APPEND:
        filep->access.fp = fopen(path, "a");
        break;
    }
 
#endif
    if (!found) {
        /* File did not exist before fopen was called.
         * Maybe it has been created now. Get stat info
         * like creation time now. */
        found = mg_stat(conn, path, &(filep->stat));
        (void)found;
    }
 
    /* return OK if file is opened */
    return (filep->access.fp != NULL);
}
 
 
/* return 0 on success, just like fclose */
static int
mg_fclose(struct mg_file_access *fileacc)
{
    int ret = -1;
    if (fileacc != NULL) {
        if (fileacc->fp != NULL) {
            ret = fclose(fileacc->fp);
        }
        /* reset all members of fileacc */
        memset(fileacc, 0, sizeof(*fileacc));
    }
    return ret;
}
#endif /* NO_FILESYSTEMS */
 
 
static void
mg_strlcpy(char *dst, const char *src, size_t n)
{
    for (; *src != '\0' && n > 1; n--) {
        *dst++ = *src++;
    }
    *dst = '\0';
}
 
 
static int
lowercase(const char *s)
{
    return tolower((unsigned char)*s);
}
 
 
CIVETWEB_API int
mg_strncasecmp(const char *s1, const char *s2, size_t len)
{
    int diff = 0;
 
    if (len > 0) {
        do {
            diff = lowercase(s1++) - lowercase(s2++);
        } while (diff == 0 && s1[-1] != '\0' && --len > 0);
    }
 
    return diff;
}
 
 
CIVETWEB_API int
mg_strcasecmp(const char *s1, const char *s2)
{
    int diff;
 
    do {
        diff = lowercase(s1++) - lowercase(s2++);
    } while (diff == 0 && s1[-1] != '\0');
 
    return diff;
}
 
 
static char *
mg_strndup_ctx(const char *ptr, size_t len, struct mg_context *ctx)
{
    char *p;
    (void)ctx; /* Avoid Visual Studio warning if USE_SERVER_STATS is not
                * defined */
 
    if ((p = (char *)mg_malloc_ctx(len + 1, ctx)) != NULL) {
        mg_strlcpy(p, ptr, len + 1);
    }
 
    return p;
}
 
 
static char *
mg_strdup_ctx(const char *str, struct mg_context *ctx)
{
    return mg_strndup_ctx(str, strlen(str), ctx);
}
 
static char *
mg_strdup(const char *str)
{
    return mg_strndup_ctx(str, strlen(str), NULL);
}
 
 
static const char *
mg_strcasestr(const char *big_str, const char *small_str)
{
    size_t i, big_len = strlen(big_str), small_len = strlen(small_str);
 
    if (big_len >= small_len) {
        for (i = 0; i <= (big_len - small_len); i++) {
            if (mg_strncasecmp(big_str + i, small_str, small_len) == 0) {
                return big_str + i;
            }
        }
    }
 
    return NULL;
}
 
 
/* Return null terminated string of given maximum length.
 * Report errors if length is exceeded. */
static void
mg_vsnprintf(const struct mg_connection *conn,
             int *truncated,
             char *buf,
             size_t buflen,
             const char *fmt,
             va_list ap)
{
    int n, ok;
 
    if (buflen == 0) {
        if (truncated) {
            *truncated = 1;
        }
        return;
    }
 
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wformat-nonliteral"
    /* Using fmt as a non-literal is intended here, since it is mostly called
     * indirectly by mg_snprintf */
#endif
 
    n = (int)vsnprintf_impl(buf, buflen, fmt, ap);
    ok = (n >= 0) && ((size_t)n < buflen);
 
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
 
    if (ok) {
        if (truncated) {
            *truncated = 0;
        }
    } else {
        if (truncated) {
            *truncated = 1;
        }
        mg_cry_internal(conn,
                        "truncating vsnprintf buffer: [%.*s]",
                        (int)((buflen > 200) ? 200 : (buflen - 1)),
                        buf);
        n = (int)buflen - 1;
    }
    buf[n] = '\0';
}
 
 
static void
mg_snprintf(const struct mg_connection *conn,
            int *truncated,
            char *buf,
            size_t buflen,
            const char *fmt,
            ...)
{
    va_list ap;
 
    va_start(ap, fmt);
    mg_vsnprintf(conn, truncated, buf, buflen, fmt, ap);
    va_end(ap);
}
 
 
static int
get_option_index(const char *name)
{
    int i;
 
    for (i = 0; config_options[i].name != NULL; i++) {
        if (strcmp(config_options[i].name, name) == 0) {
            return i;
        }
    }
    return -1;
}
 
 
CIVETWEB_API const char *
mg_get_option(const struct mg_context *ctx, const char *name)
{
    int i;
    if ((i = get_option_index(name)) == -1) {
        return NULL;
    } else if (!ctx || ctx->dd.config[i] == NULL) {
        return "";
    } else {
        return ctx->dd.config[i];
    }
}
 
#define mg_get_option DO_NOT_USE_THIS_FUNCTION_INTERNALLY__access_directly
 
CIVETWEB_API struct mg_context *
mg_get_context(const struct mg_connection *conn)
{
    return (conn == NULL) ? (struct mg_context *)NULL : (conn->phys_ctx);
}
 
 
CIVETWEB_API void *
mg_get_user_data(const struct mg_context *ctx)
{
    return (ctx == NULL) ? NULL : ctx->user_data;
}
 
 
CIVETWEB_API void *
mg_get_user_context_data(const struct mg_connection *conn)
{
    return mg_get_user_data(mg_get_context(conn));
}
 
 
CIVETWEB_API void *
mg_get_thread_pointer(const struct mg_connection *conn)
{
    /* both methods should return the same pointer */
    if (conn) {
        /* quick access, in case conn is known */
        return conn->tls_user_ptr;
    } else {
        /* otherwise get pointer from thread local storage (TLS) */
        struct mg_workerTLS *tls =
            (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
        return tls->user_ptr;
    }
}
 
 
CIVETWEB_API void
mg_set_user_connection_data(const struct mg_connection *const_conn, void *data)
{
    if (const_conn != NULL) {
        /* Const cast, since "const struct mg_connection *" does not mean
         * the connection object is not modified. Here "const" is used,
         * to indicate mg_read/mg_write/mg_send/.. must not be called. */
        struct mg_connection *conn = (struct mg_connection *)const_conn;
        conn->request_info.conn_data = data;
    }
}
 
 
CIVETWEB_API void *
mg_get_user_connection_data(const struct mg_connection *conn)
{
    if (conn != NULL) {
        return conn->request_info.conn_data;
    }
    return NULL;
}
 
 
CIVETWEB_API int
mg_get_server_ports(const struct mg_context *ctx,
                    int size,
                    struct mg_server_port *ports)
{
    int i, cnt = 0;
 
    if (size <= 0) {
        return -1;
    }
    memset(ports, 0, sizeof(*ports) * (size_t)size);
    if (!ctx) {
        return -1;
    }
    if (!ctx->listening_sockets) {
        return -1;
    }
 
    for (i = 0; (i < size) && (i < (int)ctx->num_listening_sockets); i++) {
 
        ports[cnt].port =
            ntohs(USA_IN_PORT_UNSAFE(&(ctx->listening_sockets[i].lsa)));
        ports[cnt].is_ssl = ctx->listening_sockets[i].is_ssl;
        ports[cnt].is_redirect = ctx->listening_sockets[i].ssl_redir;
 
        if (ctx->listening_sockets[i].lsa.sa.sa_family == AF_INET) {
            /* IPv4 */
            ports[cnt].protocol = 1;
            cnt++;
        } else if (ctx->listening_sockets[i].lsa.sa.sa_family == AF_INET6) {
            /* IPv6 */
            ports[cnt].protocol = 3;
            cnt++;
        }
    }
 
    return cnt;
}
 
 
#if defined(USE_X_DOM_SOCKET) && !defined(UNIX_DOMAIN_SOCKET_SERVER_NAME)
#define UNIX_DOMAIN_SOCKET_SERVER_NAME "*"
#endif
 
static void
sockaddr_to_string(char *buf, size_t len, const union usa *usa)
{
    buf[0] = '\0';
 
    if (!usa) {
        return;
    }
 
    if (usa->sa.sa_family == AF_INET) {
        getnameinfo(&usa->sa,
                    sizeof(usa->sin),
                    buf,
                    (unsigned)len,
                    NULL,
                    0,
                    NI_NUMERICHOST);
    }
#if defined(USE_IPV6)
    else if (usa->sa.sa_family == AF_INET6) {
        getnameinfo(&usa->sa,
                    sizeof(usa->sin6),
                    buf,
                    (unsigned)len,
                    NULL,
                    0,
                    NI_NUMERICHOST);
    }
#endif
#if defined(USE_X_DOM_SOCKET)
    else if (usa->sa.sa_family == AF_UNIX) {
        /* TODO: Define a remote address for unix domain sockets.
        * This code will always return "localhost", identical to http+tcp:
        getnameinfo(&usa->sa,
        sizeof(usa->sun),
        buf,
        (unsigned)len,
        NULL,
        0,
        NI_NUMERICHOST);
        */
        mg_strlcpy(buf, UNIX_DOMAIN_SOCKET_SERVER_NAME, len);
    }
#endif
}
 
 
/* Convert time_t to a string. According to RFC2616, Sec 14.18, this must be
 * included in all responses other than 100, 101, 5xx. */
static void
gmt_time_string(char *buf, size_t buf_len, time_t *t)
{
#if !defined(REENTRANT_TIME)
    struct tm *tm;
 
    tm = ((t != NULL) ? gmtime(t) : NULL);
    if (tm != NULL) {
#else
    struct tm _tm;
    struct tm *tm = &_tm;
 
    if (t != NULL) {
        gmtime_r(t, tm);
#endif
        strftime(buf, buf_len, "%a, %d %b %Y %H:%M:%S GMT", tm);
    } else {
        mg_strlcpy(buf, "Thu, 01 Jan 1970 00:00:00 GMT", buf_len);
    }
}
 
 
/* difftime for struct timespec. Return value is in seconds. */
static double
mg_difftimespec(const struct timespec *ts_now, const struct timespec *ts_before)
{
    return (double)(ts_now->tv_nsec - ts_before->tv_nsec) * 1.0E-9
           + (double)(ts_now->tv_sec - ts_before->tv_sec);
}
 
 
#if defined(MG_EXTERNAL_FUNCTION_mg_cry_internal_impl)
static void mg_cry_internal_impl(const struct mg_connection *conn,
                                 const char *func,
                                 unsigned line,
                                 const char *fmt,
                                 va_list ap);
#include "external_mg_cry_internal_impl.inl"
#elif !defined(NO_FILESYSTEMS)
 
/* Print error message to the opened error log stream. */
static void
mg_cry_internal_impl(const struct mg_connection *conn,
                     const char *func,
                     unsigned line,
                     const char *fmt,
                     va_list ap)
{
    char buf[MG_BUF_LEN], src_addr[IP_ADDR_STR_LEN];
    struct mg_file fi;
    time_t timestamp;
 
    /* Unused, in the RELEASE build */
    (void)func;
    (void)line;
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#endif
 
    IGNORE_UNUSED_RESULT(vsnprintf_impl(buf, sizeof(buf), fmt, ap));
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif
 
    buf[sizeof(buf) - 1] = 0;
 
    DEBUG_TRACE("mg_cry called from %s:%u: %s", func, line, buf);
 
    if (!conn) {
        puts(buf);
        return;
    }
 
    /* Do not lock when getting the callback value, here and below.
     * I suppose this is fine, since function cannot disappear in the
     * same way string option can. */
    if ((conn->phys_ctx->callbacks.log_message == NULL)
        || (conn->phys_ctx->callbacks.log_message(conn, buf) == 0)) {
 
        if (conn->dom_ctx->config[ERROR_LOG_FILE] != NULL) {
            if (mg_fopen(conn,
                         conn->dom_ctx->config[ERROR_LOG_FILE],
                         MG_FOPEN_MODE_APPEND,
                         &fi)
                == 0) {
                fi.access.fp = NULL;
            }
        } else {
            fi.access.fp = NULL;
        }
 
        if (fi.access.fp != NULL) {
            flockfile(fi.access.fp);
            timestamp = time(NULL);
 
            sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
            fprintf(fi.access.fp,
                    "[%010lu] [error] [client %s] ",
                    (unsigned long)timestamp,
                    src_addr);
 
            if (conn->request_info.request_method != NULL) {
                fprintf(fi.access.fp,
                        "%s %s: ",
                        conn->request_info.request_method,
                        conn->request_info.request_uri
                            ? conn->request_info.request_uri
                            : "");
            }
 
            fprintf(fi.access.fp, "%s", buf);
            fputc('\n', fi.access.fp);
            fflush(fi.access.fp);
            funlockfile(fi.access.fp);
            (void)mg_fclose(&fi.access); /* Ignore errors. We can't call
                                          * mg_cry here anyway ;-) */
        }
    }
}
#else
#error Must either enable filesystems or provide a custom mg_cry_internal_impl implementation
#endif /* Externally provided function */
 
 
/* Construct fake connection structure. Used for logging, if connection
 * is not applicable at the moment of logging. */
static struct mg_connection *
fake_connection(struct mg_connection *fc, struct mg_context *ctx)
{
    static const struct mg_connection conn_zero = {0};
    *fc = conn_zero;
    fc->phys_ctx = ctx;
    fc->dom_ctx = &(ctx->dd);
    return fc;
}
 
 
static void
mg_cry_internal_wrap(const struct mg_connection *conn,
                     struct mg_context *ctx,
                     const char *func,
                     unsigned line,
                     const char *fmt,
                     ...)
{
    va_list ap;
    va_start(ap, fmt);
    if (!conn && ctx) {
        struct mg_connection fc;
        mg_cry_internal_impl(fake_connection(&fc, ctx), func, line, fmt, ap);
    } else {
        mg_cry_internal_impl(conn, func, line, fmt, ap);
    }
    va_end(ap);
}
 
 
CIVETWEB_API void
mg_cry(const struct mg_connection *conn, const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    mg_cry_internal_impl(conn, "user", 0, fmt, ap);
    va_end(ap);
}
 
 
#define mg_cry DO_NOT_USE_THIS_FUNCTION__USE_mg_cry_internal
 
 
CIVETWEB_API const char *
mg_version(void)
{
    return CIVETWEB_VERSION;
}
 
 
CIVETWEB_API const struct mg_request_info *
mg_get_request_info(const struct mg_connection *conn)
{
    if (!conn) {
        return NULL;
    }
#if defined(MG_ALLOW_USING_GET_REQUEST_INFO_FOR_RESPONSE)
    if (conn->connection_type == CONNECTION_TYPE_RESPONSE) {
        char txt[16];
        struct mg_workerTLS *tls =
            (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
 
        sprintf(txt, "%03i", conn->response_info.status_code);
        if (strlen(txt) == 3) {
            memcpy(tls->txtbuf, txt, 4);
        } else {
            strcpy(tls->txtbuf, "ERR");
        }
 
        ((struct mg_connection *)conn)->request_info.local_uri =
            tls->txtbuf; /* use thread safe buffer */
        ((struct mg_connection *)conn)->request_info.local_uri_raw =
            tls->txtbuf; /* use the same thread safe buffer */
        ((struct mg_connection *)conn)->request_info.request_uri =
            tls->txtbuf; /* use  the same thread safe buffer */
 
        ((struct mg_connection *)conn)->request_info.num_headers =
            conn->response_info.num_headers;
        memcpy(((struct mg_connection *)conn)->request_info.http_headers,
               conn->response_info.http_headers,
               sizeof(conn->response_info.http_headers));
    } else
#endif
        if (conn->connection_type != CONNECTION_TYPE_REQUEST) {
        return NULL;
    }
    return &conn->request_info;
}
 
 
CIVETWEB_API const struct mg_response_info *
mg_get_response_info(const struct mg_connection *conn)
{
    if (!conn) {
        return NULL;
    }
    if (conn->connection_type != CONNECTION_TYPE_RESPONSE) {
        return NULL;
    }
    return &conn->response_info;
}
 
 
static const char *
get_proto_name(const struct mg_connection *conn)
{
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code"
    /* Depending on USE_WEBSOCKET and NO_SSL, some oft the protocols might be
     * not supported. Clang raises an "unreachable code" warning for parts of ?:
     * unreachable, but splitting into four different #ifdef clauses here is
     * more complicated.
     */
#endif
 
    const struct mg_request_info *ri = &conn->request_info;
 
    const char *proto = ((conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET)
                             ? (ri->is_ssl ? "wss" : "ws")
                             : (ri->is_ssl ? "https" : "http"));
 
    return proto;
 
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
}
 
 
static int
mg_construct_local_link(const struct mg_connection *conn,
                        char *buf,
                        size_t buflen,
                        const char *define_proto,
                        int define_port,
                        const char *define_uri)
{
    if ((buflen < 1) || (buf == 0) || (conn == 0)) {
        return -1;
    } else {
        int i, j;
        int truncated = 0;
        const struct mg_request_info *ri = &conn->request_info;
 
        const char *proto =
            (define_proto != NULL) ? define_proto : get_proto_name(conn);
        const char *uri =
            (define_uri != NULL)
                ? define_uri
                : ((ri->request_uri != NULL) ? ri->request_uri : ri->local_uri);
        int port = (define_port > 0) ? define_port : ri->server_port;
        int default_port = 80;
        char *uri_encoded;
        size_t uri_encoded_len;
 
        if (uri == NULL) {
            return -1;
        }
 
        uri_encoded_len = strlen(uri) * 3 + 1;
        uri_encoded = (char *)mg_malloc_ctx(uri_encoded_len, conn->phys_ctx);
        if (uri_encoded == NULL) {
            return -1;
        }
        mg_url_encode(uri, uri_encoded, uri_encoded_len);
 
        /* Directory separator should be preserved. */
        for (i = j = 0; uri_encoded[i]; j++) {
            if (!strncmp(uri_encoded + i, "%2f", 3)) {
                uri_encoded[j] = '/';
                i += 3;
            } else {
                uri_encoded[j] = uri_encoded[i++];
            }
        }
        uri_encoded[j] = '\0';
 
#if defined(USE_X_DOM_SOCKET)
        if (conn->client.lsa.sa.sa_family == AF_UNIX) {
            /* TODO: Define and document a link for UNIX domain sockets. */
            /* There seems to be no official standard for this.
             * Common uses seem to be "httpunix://", "http.unix://" or
             * "http+unix://" as a protocol definition string, followed by
             * "localhost" or "127.0.0.1" or "/tmp/unix/path" or
             * "%2Ftmp%2Funix%2Fpath" (url % encoded) or
             * "localhost:%2Ftmp%2Funix%2Fpath" (domain socket path as port) or
             * "" (completely skipping the server name part). In any case, the
             * last part is the server local path. */
            const char *server_name = UNIX_DOMAIN_SOCKET_SERVER_NAME;
            mg_snprintf(conn,
                        &truncated,
                        buf,
                        buflen,
                        "%s.unix://%s%s",
                        proto,
                        server_name,
                        ri->local_uri);
            default_port = 0;
            mg_free(uri_encoded);
            return 0;
        }
#endif
 
        if (define_proto) {
            /* If we got a protocol name, use the default port accordingly. */
            if ((0 == strcmp(define_proto, "https"))
                || (0 == strcmp(define_proto, "wss"))) {
                default_port = 443;
            }
        } else if (ri->is_ssl) {
            /* If we did not get a protocol name, use TLS as default if it is
             * already used. */
            default_port = 443;
        }
 
        {
#if defined(USE_IPV6)
            int is_ipv6 = (conn->client.lsa.sa.sa_family == AF_INET6);
#endif
            int auth_domain_check_enabled =
                conn->dom_ctx->config[ENABLE_AUTH_DOMAIN_CHECK]
                && (!mg_strcasecmp(
                       conn->dom_ctx->config[ENABLE_AUTH_DOMAIN_CHECK], "yes"));
 
            const char *server_domain =
                conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
 
            char portstr[16];
            char server_ip[48];
 
            if (port != default_port) {
                sprintf(portstr, ":%u", (unsigned)port);
            } else {
                portstr[0] = 0;
            }
 
            if (!auth_domain_check_enabled || !server_domain) {
 
                sockaddr_to_string(server_ip,
                                   sizeof(server_ip),
                                   &conn->client.lsa);
 
                server_domain = server_ip;
            }
 
            mg_snprintf(conn,
                        &truncated,
                        buf,
                        buflen,
#if defined(USE_IPV6)
                        "%s://%s%s%s%s%s",
                        proto,
                        (is_ipv6 && (server_domain == server_ip)) ? "[" : "",
                        server_domain,
                        (is_ipv6 && (server_domain == server_ip)) ? "]" : "",
#else
                        "%s://%s%s%s",
                        proto,
                        server_domain,
#endif
                        portstr,
                        uri_encoded);
 
            mg_free(uri_encoded);
            if (truncated) {
                return -1;
            }
            return 0;
        }
    }
}
 
 
CIVETWEB_API int
mg_get_request_link(const struct mg_connection *conn, char *buf, size_t buflen)
{
    return mg_construct_local_link(conn, buf, buflen, NULL, -1, NULL);
}
 
 
/* Skip the characters until one of the delimiters characters found.
 * 0-terminate resulting word. Skip the delimiter and following whitespaces.
 * Advance pointer to buffer to the next word. Return found 0-terminated
 * word.
 * Delimiters can be quoted with quotechar. */
static char *
skip_quoted(char **buf,
            const char *delimiters,
            const char *whitespace,
            char quotechar)
{
    char *p, *begin_word, *end_word, *end_whitespace;
 
    begin_word = *buf;
    end_word = begin_word + strcspn(begin_word, delimiters);
 
    /* Check for quotechar */
    if (end_word > begin_word) {
        p = end_word - 1;
        while (*p == quotechar) {
            /* While the delimiter is quoted, look for the next delimiter. */
            /* This happens, e.g., in calls from parse_auth_header,
             * if the user name contains a " character. */
 
            /* If there is anything beyond end_word, copy it. */
            if (*end_word != '\0') {
                size_t end_off = strcspn(end_word + 1, delimiters);
                memmove(p, end_word, end_off + 1);
                p += end_off; /* p must correspond to end_word - 1 */
                end_word += end_off + 1;
            } else {
                *p = '\0';
                break;
            }
        }
        for (p++; p < end_word; p++) {
            *p = '\0';
        }
    }
 
    if (*end_word == '\0') {
        *buf = end_word;
    } else {
 
#if defined(GCC_DIAGNOSTIC)
        /* Disable spurious conversion warning for GCC */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wsign-conversion"
#endif /* defined(GCC_DIAGNOSTIC) */
 
        end_whitespace = end_word + strspn(&end_word[1], whitespace) + 1;
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */
 
        for (p = end_word; p < end_whitespace; p++) {
            *p = '\0';
        }
 
        *buf = end_whitespace;
    }
 
    return begin_word;
}
 
 
/* Return HTTP header value, or NULL if not found. */
static const char *
get_header(const struct mg_header *hdr, int num_hdr, const char *name)
{
    int i;
    for (i = 0; i < num_hdr; i++) {
        if (!mg_strcasecmp(name, hdr[i].name)) {
            return hdr[i].value;
        }
    }
 
    return NULL;
}
 
 
/* Retrieve requested HTTP header multiple values, and return the number of
 * found occurrences */
static int
get_req_headers(const struct mg_request_info *ri,
                const char *name,
                const char **output,
                int output_max_size)
{
    int i;
    int cnt = 0;
    if (ri) {
        for (i = 0; i < ri->num_headers && cnt < output_max_size; i++) {
            if (!mg_strcasecmp(name, ri->http_headers[i].name)) {
                output[cnt++] = ri->http_headers[i].value;
            }
        }
    }
    return cnt;
}
 
 
CIVETWEB_API const char *
mg_get_header(const struct mg_connection *conn, const char *name)
{
    if (!conn) {
        return NULL;
    }
 
    if (conn->connection_type == CONNECTION_TYPE_REQUEST) {
        return get_header(conn->request_info.http_headers,
                          conn->request_info.num_headers,
                          name);
    }
    if (conn->connection_type == CONNECTION_TYPE_RESPONSE) {
        return get_header(conn->response_info.http_headers,
                          conn->response_info.num_headers,
                          name);
    }
    return NULL;
}
 
 
static const char *
get_http_version(const struct mg_connection *conn)
{
    if (!conn) {
        return NULL;
    }
 
    if (conn->connection_type == CONNECTION_TYPE_REQUEST) {
        return conn->request_info.http_version;
    }
    if (conn->connection_type == CONNECTION_TYPE_RESPONSE) {
        return conn->response_info.http_version;
    }
    return NULL;
}
 
 
/* A helper function for traversing a comma separated list of values.
 * It returns a list pointer shifted to the next value, or NULL if the end
 * of the list found.
 * Value is stored in val vector. If value has form "x=y", then eq_val
 * vector is initialized to point to the "y" part, and val vector length
 * is adjusted to point only to "x". */
static const char *
next_option(const char *list, struct vec *val, struct vec *eq_val)
{
    int end;
 
reparse:
    if (val == NULL || list == NULL || *list == '\0') {
        /* End of the list */
        return NULL;
    }
 
    /* Skip over leading LWS */
    while (*list == ' ' || *list == '\t')
        list++;
 
    val->ptr = list;
    if ((list = strchr(val->ptr, ',')) != NULL) {
        /* Comma found. Store length and shift the list ptr */
        val->len = ((size_t)(list - val->ptr));
        list++;
    } else {
        /* This value is the last one */
        list = val->ptr + strlen(val->ptr);
        val->len = ((size_t)(list - val->ptr));
    }
 
    /* Adjust length for trailing LWS */
    end = (int)val->len - 1;
    while (end >= 0 && ((val->ptr[end] == ' ') || (val->ptr[end] == '\t')))
        end--;
    val->len = (size_t)(end) + (size_t)(1);
 
    if (val->len == 0) {
        /* Ignore any empty entries. */
        goto reparse;
    }
 
    if (eq_val != NULL) {
        /* Value has form "x=y", adjust pointers and lengths
         * so that val points to "x", and eq_val points to "y". */
        eq_val->len = 0;
        eq_val->ptr = (const char *)memchr(val->ptr, '=', val->len);
        if (eq_val->ptr != NULL) {
            eq_val->ptr++; /* Skip over '=' character */
            eq_val->len = ((size_t)(val->ptr - eq_val->ptr)) + val->len;
            val->len = ((size_t)(eq_val->ptr - val->ptr)) - 1;
        }
    }
 
    return list;
}
 
 
/* A helper function for checking if a comma separated list of values
 * contains
 * the given option (case insensitvely).
 * 'header' can be NULL, in which case false is returned. */
static int
header_has_option(const char *header, const char *option)
{
    struct vec opt_vec;
    struct vec eq_vec;
 
    DEBUG_ASSERT(option != NULL);
    DEBUG_ASSERT(option[0] != '\0');
 
    while ((header = next_option(header, &opt_vec, &eq_vec)) != NULL) {
        if (mg_strncasecmp(option, opt_vec.ptr, opt_vec.len) == 0)
            return 1;
    }
 
    return 0;
}
 
 
/* Sorting function implemented in a separate file */
#include "sort.inl"
 
/* Pattern matching has been reimplemented in a new file */
#include "match.inl"
 
 
/* HTTP 1.1 assumes keep alive if "Connection:" header is not set
 * This function must tolerate situations when connection info is not
 * set up, for example if request parsing failed. */
static int
should_keep_alive(const struct mg_connection *conn)
{
    const char *http_version;
    const char *header;
 
    /* First satisfy needs of the server */
    if ((conn == NULL) || conn->must_close) {
        /* Close, if civetweb framework needs to close */
        return 0;
    }
 
    if (mg_strcasecmp(conn->dom_ctx->config[ENABLE_KEEP_ALIVE], "yes") != 0) {
        /* Close, if keep alive is not enabled */
        return 0;
    }
 
    /* Check explicit wish of the client */
    header = mg_get_header(conn, "Connection");
    if (header) {
        /* If there is a connection header from the client, obey */
        if (header_has_option(header, "keep-alive")) {
            return 1;
        }
        return 0;
    }
 
    /* Use default of the standard */
    http_version = get_http_version(conn);
    if (http_version && (0 == strcmp(http_version, "1.1"))) {
        /* HTTP 1.1 default is keep alive */
        return 1;
    }
 
    /* HTTP 1.0 (and earlier) default is to close the connection */
    return 0;
}
 
 
static int
should_decode_url(const struct mg_connection *conn)
{
    if (!conn || !conn->dom_ctx) {
        return 0;
    }
 
    return (mg_strcasecmp(conn->dom_ctx->config[DECODE_URL], "yes") == 0);
}
 
 
static int
should_decode_query_string(const struct mg_connection *conn)
{
    if (!conn || !conn->dom_ctx) {
        return 0;
    }
 
    return (mg_strcasecmp(conn->dom_ctx->config[DECODE_QUERY_STRING], "yes")
            == 0);
}
 
 
static const char *
suggest_connection_header(const struct mg_connection *conn)
{
    return should_keep_alive(conn) ? "keep-alive" : "close";
}
 
 
#include "response.inl"
 
 
static void
send_no_cache_header(struct mg_connection *conn)
{
    /* Send all current and obsolete cache opt-out directives. */
    mg_response_header_add(conn,
                           "Cache-Control",
                           "no-cache, no-store, "
                           "must-revalidate, private, max-age=0",
                           -1);
    mg_response_header_add(conn, "Expires", "0", -1);
 
    if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
        /* Obsolete, but still send it for HTTP/1.0 */
        mg_response_header_add(conn, "Pragma", "no-cache", -1);
    }
}
 
 
static void
send_static_cache_header(struct mg_connection *conn)
{
#if !defined(NO_CACHING)
    int max_age;
    char val[64];
 
    const char *cache_control =
        conn->dom_ctx->config[STATIC_FILE_CACHE_CONTROL];
 
    /* If there is a full cache-control option configured,0 use it */
    if (cache_control != NULL) {
        mg_response_header_add(conn, "Cache-Control", cache_control, -1);
        return;
    }
 
    /* Read the server config to check how long a file may be cached.
     * The configuration is in seconds. */
    max_age = atoi(conn->dom_ctx->config[STATIC_FILE_MAX_AGE]);
    if (max_age <= 0) {
        /* 0 means "do not cache". All values <0 are reserved
         * and may be used differently in the future. */
        /* If a file should not be cached, do not only send
         * max-age=0, but also pragmas and Expires headers. */
        send_no_cache_header(conn);
        return;
    }
 
    /* Use "Cache-Control: max-age" instead of "Expires" header.
     * Reason: see https://www.mnot.net/blog/2007/05/15/expires_max-age */
    /* See also https://www.mnot.net/cache_docs/ */
    /* According to RFC 2616, Section 14.21, caching times should not exceed
     * one year. A year with 365 days corresponds to 31536000 seconds, a
     * leap
     * year to 31622400 seconds. For the moment, we just send whatever has
     * been configured, still the behavior for >1 year should be considered
     * as undefined. */
    mg_snprintf(
        conn, NULL, val, sizeof(val), "max-age=%lu", (unsigned long)max_age);
    mg_response_header_add(conn, "Cache-Control", val, -1);
 
#else  /* NO_CACHING */
 
    send_no_cache_header(conn);
#endif /* !NO_CACHING */
}
 
 
static void
send_additional_header(struct mg_connection *conn)
{
    const char *header = conn->dom_ctx->config[ADDITIONAL_HEADER];
 
#if !defined(NO_SSL)
    if (conn->dom_ctx->config[STRICT_HTTPS_MAX_AGE]) {
        long max_age = atol(conn->dom_ctx->config[STRICT_HTTPS_MAX_AGE]);
        if (max_age >= 0) {
            char val[64];
            mg_snprintf(conn,
                        NULL,
                        val,
                        sizeof(val),
                        "max-age=%lu",
                        (unsigned long)max_age);
            mg_response_header_add(conn, "Strict-Transport-Security", val, -1);
        }
    }
#endif
 
    if (header && header[0]) {
        mg_response_header_add_lines(conn, header);
    }
}
 
 
static void
send_cors_header(struct mg_connection *conn)
{
    const char *origin_hdr = mg_get_header(conn, "Origin");
    const char *cors_orig_cfg =
        conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_ORIGIN];
 
    if (cors_orig_cfg && *cors_orig_cfg && origin_hdr && *origin_hdr) {
        /* Cross-origin resource sharing (CORS), see
         * http://www.html5rocks.com/en/tutorials/cors/,
         * http://www.html5rocks.com/static/images/cors_server_flowchart.png
         * CORS preflight is not supported for files. */
        mg_response_header_add(conn,
                               "Access-Control-Allow-Origin",
                               cors_orig_cfg,
                               -1);
    }
}
 
 
#if !defined(NO_FILESYSTEMS)
static void handle_file_based_request(struct mg_connection *conn,
                                      const char *path,
                                      struct mg_file *filep);
#endif /* NO_FILESYSTEMS */
 
 
CIVETWEB_API const char *
mg_get_response_code_text(const struct mg_connection *conn, int response_code)
{
    /* See IANA HTTP status code assignment:
     * http://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
     */
 
    switch (response_code) {
        /* RFC2616 Section 10.1 - Informational 1xx */
    case 100:
        return "Continue"; /* RFC2616 Section 10.1.1 */
    case 101:
        return "Switching Protocols"; /* RFC2616 Section 10.1.2 */
    case 102:
        return "Processing"; /* RFC2518 Section 10.1 */
 
        /* RFC2616 Section 10.2 - Successful 2xx */
    case 200:
        return "OK"; /* RFC2616 Section 10.2.1 */
    case 201:
        return "Created"; /* RFC2616 Section 10.2.2 */
    case 202:
        return "Accepted"; /* RFC2616 Section 10.2.3 */
    case 203:
        return "Non-Authoritative Information"; /* RFC2616 Section 10.2.4 */
    case 204:
        return "No Content"; /* RFC2616 Section 10.2.5 */
    case 205:
        return "Reset Content"; /* RFC2616 Section 10.2.6 */
    case 206:
        return "Partial Content"; /* RFC2616 Section 10.2.7 */
    case 207:
        return "Multi-Status"; /* RFC2518 Section 10.2, RFC4918 Section 11.1
                                */
    case 208:
        return "Already Reported"; /* RFC5842 Section 7.1 */
 
    case 226:
        return "IM used"; /* RFC3229 Section 10.4.1 */
 
        /* RFC2616 Section 10.3 - Redirection 3xx */
    case 300:
        return "Multiple Choices"; /* RFC2616 Section 10.3.1 */
    case 301:
        return "Moved Permanently"; /* RFC2616 Section 10.3.2 */
    case 302:
        return "Found"; /* RFC2616 Section 10.3.3 */
    case 303:
        return "See Other"; /* RFC2616 Section 10.3.4 */
    case 304:
        return "Not Modified"; /* RFC2616 Section 10.3.5 */
    case 305:
        return "Use Proxy"; /* RFC2616 Section 10.3.6 */
    case 307:
        return "Temporary Redirect"; /* RFC2616 Section 10.3.8 */
    case 308:
        return "Permanent Redirect"; /* RFC7238 Section 3 */
 
        /* RFC2616 Section 10.4 - Client Error 4xx */
    case 400:
        return "Bad Request"; /* RFC2616 Section 10.4.1 */
    case 401:
        return "Unauthorized"; /* RFC2616 Section 10.4.2 */
    case 402:
        return "Payment Required"; /* RFC2616 Section 10.4.3 */
    case 403:
        return "Forbidden"; /* RFC2616 Section 10.4.4 */
    case 404:
        return "Not Found"; /* RFC2616 Section 10.4.5 */
    case 405:
        return "Method Not Allowed"; /* RFC2616 Section 10.4.6 */
    case 406:
        return "Not Acceptable"; /* RFC2616 Section 10.4.7 */
    case 407:
        return "Proxy Authentication Required"; /* RFC2616 Section 10.4.8 */
    case 408:
        return "Request Time-out"; /* RFC2616 Section 10.4.9 */
    case 409:
        return "Conflict"; /* RFC2616 Section 10.4.10 */
    case 410:
        return "Gone"; /* RFC2616 Section 10.4.11 */
    case 411:
        return "Length Required"; /* RFC2616 Section 10.4.12 */
    case 412:
        return "Precondition Failed"; /* RFC2616 Section 10.4.13 */
    case 413:
        return "Request Entity Too Large"; /* RFC2616 Section 10.4.14 */
    case 414:
        return "Request-URI Too Large"; /* RFC2616 Section 10.4.15 */
    case 415:
        return "Unsupported Media Type"; /* RFC2616 Section 10.4.16 */
    case 416:
        return "Requested range not satisfiable"; /* RFC2616 Section 10.4.17
                                                   */
    case 417:
        return "Expectation Failed"; /* RFC2616 Section 10.4.18 */
 
    case 421:
        return "Misdirected Request"; /* RFC7540 Section 9.1.2 */
    case 422:
        return "Unproccessable entity"; /* RFC2518 Section 10.3, RFC4918
                                         * Section 11.2 */
    case 423:
        return "Locked"; /* RFC2518 Section 10.4, RFC4918 Section 11.3 */
    case 424:
        return "Failed Dependency"; /* RFC2518 Section 10.5, RFC4918
                                     * Section 11.4 */
 
    case 426:
        return "Upgrade Required"; /* RFC 2817 Section 4 */
 
    case 428:
        return "Precondition Required"; /* RFC 6585, Section 3 */
    case 429:
        return "Too Many Requests"; /* RFC 6585, Section 4 */
 
    case 431:
        return "Request Header Fields Too Large"; /* RFC 6585, Section 5 */
 
    case 451:
        return "Unavailable For Legal Reasons"; /* draft-tbray-http-legally-restricted-status-05,
                                                 * Section 3 */
 
        /* RFC2616 Section 10.5 - Server Error 5xx */
    case 500:
        return "Internal Server Error"; /* RFC2616 Section 10.5.1 */
    case 501:
        return "Not Implemented"; /* RFC2616 Section 10.5.2 */
    case 502:
        return "Bad Gateway"; /* RFC2616 Section 10.5.3 */
    case 503:
        return "Service Unavailable"; /* RFC2616 Section 10.5.4 */
    case 504:
        return "Gateway Time-out"; /* RFC2616 Section 10.5.5 */
    case 505:
        return "HTTP Version not supported"; /* RFC2616 Section 10.5.6 */
    case 506:
        return "Variant Also Negotiates"; /* RFC 2295, Section 8.1 */
    case 507:
        return "Insufficient Storage"; /* RFC2518 Section 10.6, RFC4918
                                        * Section 11.5 */
    case 508:
        return "Loop Detected"; /* RFC5842 Section 7.1 */
 
    case 510:
        return "Not Extended"; /* RFC 2774, Section 7 */
    case 511:
        return "Network Authentication Required"; /* RFC 6585, Section 6 */
 
        /* Other status codes, not shown in the IANA HTTP status code
         * assignment.
         * E.g., "de facto" standards due to common use, ... */
    case 418:
        return "I am a teapot"; /* RFC2324 Section 2.3.2 */
    case 419:
        return "Authentication Timeout"; /* common use */
    case 420:
        return "Enhance Your Calm"; /* common use */
    case 440:
        return "Login Timeout"; /* common use */
    case 509:
        return "Bandwidth Limit Exceeded"; /* common use */
 
    default:
        /* This error code is unknown. This should not happen. */
        if (conn) {
            mg_cry_internal(conn,
                            "Unknown HTTP response code: %u",
                            response_code);
        }
 
        /* Return at least a category according to RFC 2616 Section 10. */
        if (response_code >= 100 && response_code < 200) {
            /* Unknown informational status code */
            return "Information";
        }
        if (response_code >= 200 && response_code < 300) {
            /* Unknown success code */
            return "Success";
        }
        if (response_code >= 300 && response_code < 400) {
            /* Unknown redirection code */
            return "Redirection";
        }
        if (response_code >= 400 && response_code < 500) {
            /* Unknown request error code */
            return "Client Error";
        }
        if (response_code >= 500 && response_code < 600) {
            /* Unknown server error code */
            return "Server Error";
        }
 
        /* Response code not even within reasonable range */
        return "";
    }
}
 
 
static int
mg_send_http_error_impl(struct mg_connection *conn,
                        int status,
                        const char *fmt,
                        va_list args)
{
    char errmsg_buf[MG_BUF_LEN];
    va_list ap;
    int has_body;
 
#if !defined(NO_FILESYSTEMS)
    char path_buf[UTF8_PATH_MAX];
    int len, i, page_handler_found, scope, truncated;
    const char *error_handler = NULL;
    struct mg_file error_page_file = STRUCT_FILE_INITIALIZER;
    const char *error_page_file_ext, *tstr;
#endif /* NO_FILESYSTEMS */
    int handled_by_callback = 0;
 
    if ((conn == NULL) || (fmt == NULL)) {
        return -2;
    }
 
    /* Set status (for log) */
    conn->status_code = status;
 
    /* Errors 1xx, 204 and 304 MUST NOT send a body */
    has_body = ((status > 199) && (status != 204) && (status != 304));
 
    /* Prepare message in buf, if required */
    if (has_body
        || (!conn->in_error_handler
            && (conn->phys_ctx->callbacks.http_error != NULL))) {
        /* Store error message in errmsg_buf */
        va_copy(ap, args);
        mg_vsnprintf(conn, NULL, errmsg_buf, sizeof(errmsg_buf), fmt, ap);
        va_end(ap);
        /* In a debug build, print all html errors */
        DEBUG_TRACE("Error %i - [%s]", status, errmsg_buf);
    }
 
    /* If there is a http_error callback, call it.
     * But don't do it recursively, if callback calls mg_send_http_error again.
     */
    if (!conn->in_error_handler
        && (conn->phys_ctx->callbacks.http_error != NULL)) {
        /* Mark in_error_handler to avoid recursion and call user callback. */
        conn->in_error_handler = 1;
        handled_by_callback =
            (conn->phys_ctx->callbacks.http_error(conn, status, errmsg_buf)
             == 0);
        conn->in_error_handler = 0;
    }
 
    if (!handled_by_callback) {
        /* Check for recursion */
        if (conn->in_error_handler) {
            DEBUG_TRACE(
                "Recursion when handling error %u - fall back to default",
                status);
#if !defined(NO_FILESYSTEMS)
        } else {
            /* Send user defined error pages, if defined */
            error_handler = conn->dom_ctx->config[ERROR_PAGES];
            error_page_file_ext = conn->dom_ctx->config[INDEX_FILES];
            page_handler_found = 0;
 
            if (error_handler != NULL) {
                for (scope = 1; (scope <= 3) && !page_handler_found; scope++) {
                    switch (scope) {
                    case 1: /* Handler for specific error, e.g. 404 error */
                        mg_snprintf(conn,
                                    &truncated,
                                    path_buf,
                                    sizeof(path_buf) - 32,
                                    "%serror%03u.",
                                    error_handler,
                                    status);
                        break;
                    case 2: /* Handler for error group, e.g., 5xx error
                             * handler
                             * for all server errors (500-599) */
                        mg_snprintf(conn,
                                    &truncated,
                                    path_buf,
                                    sizeof(path_buf) - 32,
                                    "%serror%01uxx.",
                                    error_handler,
                                    status / 100);
                        break;
                    default: /* Handler for all errors */
                        mg_snprintf(conn,
                                    &truncated,
                                    path_buf,
                                    sizeof(path_buf) - 32,
                                    "%serror.",
                                    error_handler);
                        break;
                    }
 
                    /* String truncation in buf may only occur if
                     * error_handler is too long. This string is
                     * from the config, not from a client. */
                    (void)truncated;
 
                    /* The following code is redundant, but it should avoid
                     * false positives in static source code analyzers and
                     * vulnerability scanners.
                     */
                    path_buf[sizeof(path_buf) - 32] = 0;
                    len = (int)strlen(path_buf);
                    if (len > (int)sizeof(path_buf) - 32) {
                        len = (int)sizeof(path_buf) - 32;
                    }
 
                    /* Start with the file extension from the configuration. */
                    tstr = strchr(error_page_file_ext, '.');
 
                    while (tstr) {
                        for (i = 1;
                             (i < 32) && (tstr[i] != 0) && (tstr[i] != ',');
                             i++) {
                            /* buffer overrun is not possible here, since
                             * (i < 32) && (len < sizeof(path_buf) - 32)
                             * ==> (i + len) < sizeof(path_buf) */
                            path_buf[len + i - 1] = tstr[i];
                        }
                        /* buffer overrun is not possible here, since
                         * (i <= 32) && (len < sizeof(path_buf) - 32)
                         * ==> (i + len) <= sizeof(path_buf) */
                        path_buf[len + i - 1] = 0;
 
                        if (mg_stat(conn, path_buf, &error_page_file.stat)) {
                            DEBUG_TRACE("Check error page %s - found",
                                        path_buf);
                            page_handler_found = 1;
                            break;
                        }
                        DEBUG_TRACE("Check error page %s - not found",
                                    path_buf);
 
                        /* Continue with the next file extension from the
                         * configuration (if there is a next one). */
                        tstr = strchr(tstr + i, '.');
                    }
                }
            }
 
            if (page_handler_found) {
                conn->in_error_handler = 1;
                handle_file_based_request(conn, path_buf, &error_page_file);
                conn->in_error_handler = 0;
                return 0;
            }
#endif /* NO_FILESYSTEMS */
        }
 
        /* No custom error page. Send default error page. */
        conn->must_close = 1;
        mg_response_header_start(conn, status);
        send_no_cache_header(conn);
        send_additional_header(conn);
        send_cors_header(conn);
        if (has_body) {
            mg_response_header_add(conn,
                                   "Content-Type",
                                   "text/plain; charset=utf-8",
                                   -1);
        }
        mg_response_header_send(conn);
 
        /* HTTP responses 1xx, 204 and 304 MUST NOT send a body */
        if (has_body) {
            /* For other errors, send a generic error message. */
            const char *status_text = mg_get_response_code_text(conn, status);
            mg_printf(conn, "Error %d: %s\n", status, status_text);
            mg_write(conn, errmsg_buf, strlen(errmsg_buf));
 
        } else {
            /* No body allowed. Close the connection. */
            DEBUG_TRACE("Error %i", status);
        }
    }
    return 0;
}
 
 
CIVETWEB_API int
mg_send_http_error(struct mg_connection *conn, int status, const char *fmt, ...)
{
    va_list ap;
    int ret;
 
    va_start(ap, fmt);
    ret = mg_send_http_error_impl(conn, status, fmt, ap);
    va_end(ap);
 
    return ret;
}
 
 
CIVETWEB_API int
mg_send_http_ok(struct mg_connection *conn,
                const char *mime_type,
                long long content_length)
{
    if ((mime_type == NULL) || (*mime_type == 0)) {
        /* No content type defined: default to text/html */
        mime_type = "text/html";
    }
 
    mg_response_header_start(conn, 200);
    send_no_cache_header(conn);
    send_additional_header(conn);
    send_cors_header(conn);
    mg_response_header_add(conn, "Content-Type", mime_type, -1);
    if (content_length < 0) {
        /* Size not known. Use chunked encoding (HTTP/1.x) */
        if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
            /* Only HTTP/1.x defines "chunked" encoding, HTTP/2 does not*/
            mg_response_header_add(conn, "Transfer-Encoding", "chunked", -1);
        }
    } else {
        char len[32];
        int trunc = 0;
        mg_snprintf(conn,
                    &trunc,
                    len,
                    sizeof(len),
                    "%" UINT64_FMT,
                    (uint64_t)content_length);
        if (!trunc) {
            /* Since 32 bytes is enough to hold any 64 bit decimal number,
             * !trunc is always true */
            mg_response_header_add(conn, "Content-Length", len, -1);
        }
    }
    mg_response_header_send(conn);
 
    return 0;
}
 
 
CIVETWEB_API int
mg_send_http_redirect(struct mg_connection *conn,
                      const char *target_url,
                      int redirect_code)
{
    /* Send a 30x redirect response.
     *
     * Redirect types (status codes):
     *
     * Status | Perm/Temp | Method              | Version
     *   301  | permanent | POST->GET undefined | HTTP/1.0
     *   302  | temporary | POST->GET undefined | HTTP/1.0
     *   303  | temporary | always use GET      | HTTP/1.1
     *   307  | temporary | always keep method  | HTTP/1.1
     *   308  | permanent | always keep method  | HTTP/1.1
     */
 
#if defined(MG_SEND_REDIRECT_BODY)
    char redirect_body[MG_BUF_LEN];
    size_t content_len = 0;
    char content_len_text[32];
#endif
 
    /* In case redirect_code=0, use 307. */
    if (redirect_code == 0) {
        redirect_code = 307;
    }
 
    /* In case redirect_code is none of the above, return error. */
    if ((redirect_code != 301) && (redirect_code != 302)
        && (redirect_code != 303) && (redirect_code != 307)
        && (redirect_code != 308)) {
        /* Parameter error */
        return -2;
    }
 
    /* If target_url is not defined, redirect to "/". */
    if ((target_url == NULL) || (*target_url == 0)) {
        target_url = "/";
    }
 
#if defined(MG_SEND_REDIRECT_BODY)
    /* TODO: condition name? */
 
    /* Prepare a response body with a hyperlink.
     *
     * According to RFC2616 (and RFC1945 before):
     * Unless the request method was HEAD, the entity of the
     * response SHOULD contain a short hypertext note with a hyperlink to
     * the new URI(s).
     *
     * However, this response body is not useful in M2M communication.
     * Probably the original reason in the RFC was, clients not supporting
     * a 30x HTTP redirect could still show the HTML page and let the user
     * press the link. Since current browsers support 30x HTTP, the additional
     * HTML body does not seem to make sense anymore.
     *
     * The new RFC7231 (Section 6.4) does no longer recommend it ("SHOULD"),
     * but it only notes:
     * The server's response payload usually contains a short
     * hypertext note with a hyperlink to the new URI(s).
     *
     * Deactivated by default. If you need the 30x body, set the define.
     */
    mg_snprintf(
        conn,
        NULL /* ignore truncation */,
        redirect_body,
        sizeof(redirect_body),
        "<html><head>%s</head><body><a href=\"%s\">%s</a></body></html>",
        redirect_text,
        target_url,
        target_url);
    content_len = strlen(reply);
    sprintf(content_len_text, "%lu", (unsigned long)content_len);
#endif
 
    /* Send all required headers */
    mg_response_header_start(conn, redirect_code);
    mg_response_header_add(conn, "Location", target_url, -1);
    if ((redirect_code == 301) || (redirect_code == 308)) {
        /* Permanent redirect */
        send_static_cache_header(conn);
    } else {
        /* Temporary redirect */
        send_no_cache_header(conn);
    }
    send_additional_header(conn);
    send_cors_header(conn);
#if defined(MG_SEND_REDIRECT_BODY)
    mg_response_header_add(conn, "Content-Type", "text/html", -1);
    mg_response_header_add(conn, "Content-Length", content_len_text, -1);
#else
    mg_response_header_add(conn, "Content-Length", "0", 1);
#endif
    mg_response_header_send(conn);
 
#if defined(MG_SEND_REDIRECT_BODY)
    /* Send response body */
    /* ... unless it is a HEAD request */
    if (0 != strcmp(conn->request_info.request_method, "HEAD")) {
        ret = mg_write(conn, redirect_body, content_len);
    }
#endif
 
    return 1;
}
 
 
#if defined(_WIN32)
/* Create substitutes for POSIX functions in Win32. */
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif
 
 
static int
pthread_mutex_init(pthread_mutex_t *mutex, void *unused)
{
    (void)unused;
    /* Always initialize as PTHREAD_MUTEX_RECURSIVE */
    InitializeCriticalSection(&mutex->sec);
    return 0;
}
 
 
static int
pthread_mutex_destroy(pthread_mutex_t *mutex)
{
    DeleteCriticalSection(&mutex->sec);
    return 0;
}
 
 
static int
pthread_mutex_lock(pthread_mutex_t *mutex)
{
    EnterCriticalSection(&mutex->sec);
    return 0;
}
 
 
static int
pthread_mutex_unlock(pthread_mutex_t *mutex)
{
    LeaveCriticalSection(&mutex->sec);
    return 0;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_init(pthread_cond_t *cv, const void *unused)
{
    (void)unused;
    (void)pthread_mutex_init(&cv->threadIdSec, &pthread_mutex_attr);
    cv->waiting_thread = NULL;
    return 0;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_timedwait(pthread_cond_t *cv,
                       pthread_mutex_t *mutex,
                       FUNCTION_MAY_BE_UNUSED const struct timespec *abstime)
{
    struct mg_workerTLS **ptls,
        *tls = (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
    int ok;
    uint64_t nsnow, nswaitabs;
    int64_t nswaitrel;
    DWORD mswaitrel;
 
    pthread_mutex_lock(&cv->threadIdSec);
    /* Add this thread to cv's waiting list */
    ptls = &cv->waiting_thread;
    for (; *ptls != NULL; ptls = &(*ptls)->next_waiting_thread)
        ;
    tls->next_waiting_thread = NULL;
    *ptls = tls;
    pthread_mutex_unlock(&cv->threadIdSec);
 
    if (abstime) {
        nsnow = mg_get_current_time_ns();
        nswaitabs =
            (((uint64_t)abstime->tv_sec) * 1000000000) + abstime->tv_nsec;
        nswaitrel = nswaitabs - nsnow;
        if (nswaitrel < 0) {
            nswaitrel = 0;
        }
        mswaitrel = (DWORD)(nswaitrel / 1000000);
    } else {
        mswaitrel = (DWORD)INFINITE;
    }
 
    pthread_mutex_unlock(mutex);
    ok = (WAIT_OBJECT_0
          == WaitForSingleObject(tls->pthread_cond_helper_mutex, mswaitrel));
    if (!ok) {
        ok = 1;
        pthread_mutex_lock(&cv->threadIdSec);
        ptls = &cv->waiting_thread;
        for (; *ptls != NULL; ptls = &(*ptls)->next_waiting_thread) {
            if (*ptls == tls) {
                *ptls = tls->next_waiting_thread;
                ok = 0;
                break;
            }
        }
        pthread_mutex_unlock(&cv->threadIdSec);
        if (ok) {
            WaitForSingleObject(tls->pthread_cond_helper_mutex,
                                (DWORD)INFINITE);
        }
    }
    /* This thread has been removed from cv's waiting list */
    pthread_mutex_lock(mutex);
 
    return ok ? 0 : -1;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex)
{
    return pthread_cond_timedwait(cv, mutex, NULL);
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_signal(pthread_cond_t *cv)
{
    HANDLE wkup = NULL;
    BOOL ok = FALSE;
 
    pthread_mutex_lock(&cv->threadIdSec);
    if (cv->waiting_thread) {
        wkup = cv->waiting_thread->pthread_cond_helper_mutex;
        cv->waiting_thread = cv->waiting_thread->next_waiting_thread;
 
        ok = SetEvent(wkup);
        DEBUG_ASSERT(ok);
    }
    pthread_mutex_unlock(&cv->threadIdSec);
 
    return ok ? 0 : 1;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_broadcast(pthread_cond_t *cv)
{
    pthread_mutex_lock(&cv->threadIdSec);
    while (cv->waiting_thread) {
        pthread_cond_signal(cv);
    }
    pthread_mutex_unlock(&cv->threadIdSec);
 
    return 0;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
pthread_cond_destroy(pthread_cond_t *cv)
{
    pthread_mutex_lock(&cv->threadIdSec);
    DEBUG_ASSERT(cv->waiting_thread == NULL);
    pthread_mutex_unlock(&cv->threadIdSec);
    pthread_mutex_destroy(&cv->threadIdSec);
 
    return 0;
}
 
 
#if defined(ALTERNATIVE_QUEUE)
FUNCTION_MAY_BE_UNUSED
static void *
event_create(void)
{
    return (void *)CreateEvent(NULL, FALSE, FALSE, NULL);
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
event_wait(void *eventhdl)
{
    int res = WaitForSingleObject((HANDLE)eventhdl, (DWORD)INFINITE);
    return (res == WAIT_OBJECT_0);
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
event_signal(void *eventhdl)
{
    return (int)SetEvent((HANDLE)eventhdl);
}
 
 
FUNCTION_MAY_BE_UNUSED
static void
event_destroy(void *eventhdl)
{
    CloseHandle((HANDLE)eventhdl);
}
#endif
 
 
#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif
 
 
/* For Windows, change all slashes to backslashes in path names. */
static void
change_slashes_to_backslashes(char *path)
{
    int i;
 
    for (i = 0; path[i] != '\0'; i++) {
        if (path[i] == '/') {
            path[i] = '\\';
        }
 
        /* remove double backslash (check i > 0 to preserve UNC paths,
         * like \\server\file.txt) */
        if ((i > 0) && (path[i] == '\\')) {
            while ((path[i + 1] == '\\') || (path[i + 1] == '/')) {
                (void)memmove(path + i + 1, path + i + 2, strlen(path + i + 1));
            }
        }
    }
}
 
 
static int
mg_wcscasecmp(const wchar_t *s1, const wchar_t *s2)
{
    int diff;
 
    do {
        diff = ((*s1 >= L'A') && (*s1 <= L'Z') ? (*s1 - L'A' + L'a') : *s1)
               - ((*s2 >= L'A') && (*s2 <= L'Z') ? (*s2 - L'A' + L'a') : *s2);
        s1++;
        s2++;
    } while ((diff == 0) && (s1[-1] != L'\0'));
 
    return diff;
}
 
 
/* Encode 'path' which is assumed UTF-8 string, into UNICODE string.
 * wbuf and wbuf_len is a target buffer and its length. */
static void
path_to_unicode(const struct mg_connection *conn,
                const char *path,
                wchar_t *wbuf,
                size_t wbuf_len)
{
    char buf[UTF8_PATH_MAX], buf2[UTF8_PATH_MAX];
    wchar_t wbuf2[UTF16_PATH_MAX + 1];
    DWORD long_len, err;
    int (*fcompare)(const wchar_t *, const wchar_t *) = mg_wcscasecmp;
 
    mg_strlcpy(buf, path, sizeof(buf));
    change_slashes_to_backslashes(buf);
 
    /* Convert to Unicode and back. If doubly-converted string does not
     * match the original, something is fishy, reject. */
    memset(wbuf, 0, wbuf_len * sizeof(wchar_t));
    MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, (int)wbuf_len);
    WideCharToMultiByte(
        CP_UTF8, 0, wbuf, (int)wbuf_len, buf2, sizeof(buf2), NULL, NULL);
    if (strcmp(buf, buf2) != 0) {
        wbuf[0] = L'\0';
    }
 
    /* Windows file systems are not case sensitive, but you can still use
     * uppercase and lowercase letters (on all modern file systems).
     * The server can check if the URI uses the same upper/lowercase
     * letters an the file system, effectively making Windows servers
     * case sensitive (like Linux servers are). It is still not possible
     * to use two files with the same name in different cases on Windows
     * (like /a and /A) - this would be possible in Linux.
     * As a default, Windows is not case sensitive, but the case sensitive
     * file name check can be activated by an additional configuration. */
    if (conn) {
        if (conn->dom_ctx->config[CASE_SENSITIVE_FILES]
            && !mg_strcasecmp(conn->dom_ctx->config[CASE_SENSITIVE_FILES],
                              "yes")) {
            /* Use case sensitive compare function */
            fcompare = wcscmp;
        }
    }
    (void)conn; /* conn is currently unused */
 
    /* Only accept a full file path, not a Windows short (8.3) path. */
    memset(wbuf2, 0, ARRAY_SIZE(wbuf2) * sizeof(wchar_t));
    long_len = GetLongPathNameW(wbuf, wbuf2, ARRAY_SIZE(wbuf2) - 1);
    if (long_len == 0) {
        err = GetLastError();
        if (err == ERROR_FILE_NOT_FOUND) {
            /* File does not exist. This is not always a problem here. */
            return;
        }
    }
    if ((long_len >= ARRAY_SIZE(wbuf2)) || (fcompare(wbuf, wbuf2) != 0)) {
        /* Short name is used. */
        wbuf[0] = L'\0';
    }
}
 
 
#if !defined(NO_FILESYSTEMS)
/* Get file information, return 1 if file exists, 0 if not */
static int
mg_stat(const struct mg_connection *conn,
        const char *path,
        struct mg_file_stat *filep)
{
    wchar_t wbuf[UTF16_PATH_MAX];
    WIN32_FILE_ATTRIBUTE_DATA info;
    time_t creation_time;
    size_t len;
 
    if (!filep) {
        return 0;
    }
    memset(filep, 0, sizeof(*filep));
 
    if (mg_path_suspicious(conn, path)) {
        return 0;
    }
 
    path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
    /* Windows happily opens files with some garbage at the end of file name.
     * For example, fopen("a.cgi    ", "r") on Windows successfully opens
     * "a.cgi", despite one would expect an error back. */
    len = strlen(path);
    if ((len > 0) && (path[len - 1] != ' ') && (path[len - 1] != '.')
        && (GetFileAttributesExW(wbuf, GetFileExInfoStandard, &info) != 0)) {
        filep->size = MAKEUQUAD(info.nFileSizeLow, info.nFileSizeHigh);
        filep->last_modified =
            SYS2UNIX_TIME(info.ftLastWriteTime.dwLowDateTime,
                          info.ftLastWriteTime.dwHighDateTime);
 
        /* On Windows, the file creation time can be higher than the
         * modification time, e.g. when a file is copied.
         * Since the Last-Modified timestamp is used for caching
         * it should be based on the most recent timestamp. */
        creation_time = SYS2UNIX_TIME(info.ftCreationTime.dwLowDateTime,
                                      info.ftCreationTime.dwHighDateTime);
        if (creation_time > filep->last_modified) {
            filep->last_modified = creation_time;
        }
 
        filep->is_directory = info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
        return 1;
    }
 
    return 0;
}
#endif
 
 
static int
mg_remove(const struct mg_connection *conn, const char *path)
{
    wchar_t wbuf[UTF16_PATH_MAX];
    path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
    return DeleteFileW(wbuf) ? 0 : -1;
}
 
 
static int
mg_mkdir(const struct mg_connection *conn, const char *path, int mode)
{
    wchar_t wbuf[UTF16_PATH_MAX];
    (void)mode;
    path_to_unicode(conn, path, wbuf, ARRAY_SIZE(wbuf));
    return CreateDirectoryW(wbuf, NULL) ? 0 : -1;
}
 
 
/* Create substitutes for POSIX functions in Win32. */
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif
 
 
/* Implementation of POSIX opendir/closedir/readdir for Windows. */
FUNCTION_MAY_BE_UNUSED
static DIR *
mg_opendir(const struct mg_connection *conn, const char *name)
{
    DIR *dir = NULL;
    wchar_t wpath[UTF16_PATH_MAX];
    DWORD attrs;
 
    if (name == NULL) {
        SetLastError(ERROR_BAD_ARGUMENTS);
    } else if ((dir = (DIR *)mg_malloc(sizeof(*dir))) == NULL) {
        SetLastError(ERROR_NOT_ENOUGH_MEMORY);
    } else {
        path_to_unicode(conn, name, wpath, ARRAY_SIZE(wpath));
        attrs = GetFileAttributesW(wpath);
        if ((wcslen(wpath) + 2 < ARRAY_SIZE(wpath)) && (attrs != 0xFFFFFFFF)
            && ((attrs & FILE_ATTRIBUTE_DIRECTORY) != 0)) {
            (void)wcscat(wpath, L"\\*");
            dir->handle = FindFirstFileW(wpath, &dir->info);
            dir->result.d_name[0] = '\0';
        } else {
            mg_free(dir);
            dir = NULL;
        }
    }
 
    return dir;
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
mg_closedir(DIR *dir)
{
    int result = 0;
 
    if (dir != NULL) {
        if (dir->handle != INVALID_HANDLE_VALUE)
            result = FindClose(dir->handle) ? 0 : -1;
 
        mg_free(dir);
    } else {
        result = -1;
        SetLastError(ERROR_BAD_ARGUMENTS);
    }
 
    return result;
}
 
 
FUNCTION_MAY_BE_UNUSED
static struct dirent *
mg_readdir(DIR *dir)
{
    struct dirent *result = 0;
 
    if (dir) {
        if (dir->handle != INVALID_HANDLE_VALUE) {
            result = &dir->result;
            (void)WideCharToMultiByte(CP_UTF8,
                                      0,
                                      dir->info.cFileName,
                                      -1,
                                      result->d_name,
                                      sizeof(result->d_name),
                                      NULL,
                                      NULL);
 
            if (!FindNextFileW(dir->handle, &dir->info)) {
                (void)FindClose(dir->handle);
                dir->handle = INVALID_HANDLE_VALUE;
            }
 
        } else {
            SetLastError(ERROR_FILE_NOT_FOUND);
        }
    } else {
        SetLastError(ERROR_BAD_ARGUMENTS);
    }
 
    return result;
}
 
 
#if !defined(HAVE_POLL)
#undef POLLIN
#undef POLLPRI
#undef POLLOUT
#undef POLLERR
#define POLLIN (1)  /* Data ready - read will not block. */
#define POLLPRI (2) /* Priority data ready. */
#define POLLOUT (4) /* Send queue not full - write will not block. */
#define POLLERR (8) /* Error event */
 
FUNCTION_MAY_BE_UNUSED
static int
poll(struct mg_pollfd *pfd, unsigned int n, int milliseconds)
{
    struct timeval tv;
    fd_set rset;
    fd_set wset;
    fd_set eset;
    unsigned int i;
    int result;
    SOCKET maxfd = 0;
 
    memset(&tv, 0, sizeof(tv));
    tv.tv_sec = milliseconds / 1000;
    tv.tv_usec = (milliseconds % 1000) * 1000;
    FD_ZERO(&rset);
    FD_ZERO(&wset);
    FD_ZERO(&eset);
 
    for (i = 0; i < n; i++) {
        if (pfd[i].events & (POLLIN | POLLOUT | POLLERR)) {
            if (pfd[i].events & POLLIN) {
                FD_SET(pfd[i].fd, &rset);
            }
            if (pfd[i].events & POLLOUT) {
                FD_SET(pfd[i].fd, &wset);
            }
            /* Check for errors for any FD in the set */
            FD_SET(pfd[i].fd, &eset);
        }
        pfd[i].revents = 0;
 
        if (pfd[i].fd > maxfd) {
            maxfd = pfd[i].fd;
        }
    }
 
    if ((result = select((int)maxfd + 1, &rset, &wset, &eset, &tv)) > 0) {
        for (i = 0; i < n; i++) {
            if (FD_ISSET(pfd[i].fd, &rset)) {
                pfd[i].revents |= POLLIN;
            }
            if (FD_ISSET(pfd[i].fd, &wset)) {
                pfd[i].revents |= POLLOUT;
            }
            if (FD_ISSET(pfd[i].fd, &eset)) {
                pfd[i].revents |= POLLERR;
            }
        }
    }
 
    /* We should subtract the time used in select from remaining
     * "milliseconds", in particular if called from mg_poll with a
     * timeout quantum.
     * Unfortunately, the remaining time is not stored in "tv" in all
     * implementations, so the result in "tv" must be considered undefined.
     * See http://man7.org/linux/man-pages/man2/select.2.html */
 
    return result;
}
#endif /* HAVE_POLL */
 
 
#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif
 
 
static void
set_close_on_exec(SOCKET sock,
                  const struct mg_connection *conn /* may be null */,
                  struct mg_context *ctx /* may be null */)
{
    (void)conn; /* Unused. */
    (void)ctx;
 
    (void)SetHandleInformation((HANDLE)(intptr_t)sock, HANDLE_FLAG_INHERIT, 0);
}
 
 
CIVETWEB_API int
mg_start_thread(mg_thread_func_t f, void *p)
{
#if defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
    /* Compile-time option to control stack size, e.g.
     * -DUSE_STACK_SIZE=16384
     */
    return ((_beginthread((void(__cdecl *)(void *))f, USE_STACK_SIZE, p)
             == ((uintptr_t)(-1L)))
                ? -1
                : 0);
#else
    return (
        (_beginthread((void(__cdecl *)(void *))f, 0, p) == ((uintptr_t)(-1L)))
            ? -1
            : 0);
#endif /* defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1) */
}
 
 
/* Start a thread storing the thread context. */
static int
mg_start_thread_with_id(unsigned(__stdcall *f)(void *),
                        void *p,
                        pthread_t *threadidptr)
{
    uintptr_t uip;
    HANDLE threadhandle;
    int result = -1;
 
    uip = _beginthreadex(NULL, 0, f, p, 0, NULL);
    threadhandle = (HANDLE)uip;
    if ((uip != 0) && (threadidptr != NULL)) {
        *threadidptr = threadhandle;
        result = 0;
    }
 
    return result;
}
 
 
/* Wait for a thread to finish. */
static int
mg_join_thread(pthread_t threadid)
{
    int result;
    DWORD dwevent;
 
    result = -1;
    dwevent = WaitForSingleObject(threadid, (DWORD)INFINITE);
    if (dwevent == WAIT_FAILED) {
        DEBUG_TRACE("WaitForSingleObject() failed, error %d", ERRNO);
    } else {
        if (dwevent == WAIT_OBJECT_0) {
            CloseHandle(threadid);
            result = 0;
        }
    }
 
    return result;
}
 
#if !defined(NO_SSL_DL) && !defined(NO_SSL)
/* If SSL is loaded dynamically, dlopen/dlclose is required. */
/* Create substitutes for POSIX functions in Win32. */
 
#if defined(GCC_DIAGNOSTIC)
/* Show no warning in case system functions are not used. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-function"
#endif
 
 
FUNCTION_MAY_BE_UNUSED
static HANDLE
dlopen(const char *dll_name, int flags)
{
    wchar_t wbuf[UTF16_PATH_MAX];
    (void)flags;
    path_to_unicode(NULL, dll_name, wbuf, ARRAY_SIZE(wbuf));
    return LoadLibraryW(wbuf);
}
 
 
FUNCTION_MAY_BE_UNUSED
static int
dlclose(void *handle)
{
    int result;
 
    if (FreeLibrary((HMODULE)handle) != 0) {
        result = 0;
    } else {
        result = -1;
    }
 
    return result;
}
 
 
#if defined(GCC_DIAGNOSTIC)
/* Enable unused function warning again */
#pragma GCC diagnostic pop
#endif
 
#endif
 
 
#if !defined(NO_CGI)
#define SIGKILL (0)
 
 
static int
kill(pid_t pid, int sig_num)
{
    (void)TerminateProcess((HANDLE)pid, (UINT)sig_num);
    (void)CloseHandle((HANDLE)pid);
    return 0;
}
 
 
#if !defined(WNOHANG)
#define WNOHANG (1)
#endif
 
 
static pid_t
waitpid(pid_t pid, int *status, int flags)
{
    DWORD timeout = INFINITE;
    DWORD waitres;
 
    (void)status; /* Currently not used by any client here */
 
    if ((flags | WNOHANG) == WNOHANG) {
        timeout = 0;
    }
 
    waitres = WaitForSingleObject((HANDLE)pid, timeout);
    if (waitres == WAIT_OBJECT_0) {
        return pid;
    }
    if (waitres == WAIT_TIMEOUT) {
        return 0;
    }
    return (pid_t)-1;
}
 
 
static void
trim_trailing_whitespaces(char *s)
{
    char *e = s + strlen(s);
    while ((e > s) && isspace((unsigned char)e[-1])) {
        *(--e) = '\0';
    }
}
 
 
static pid_t
spawn_process(struct mg_connection *conn,
              const char *prog,
              char *envblk,
              char *envp[],
              int fdin[2],
              int fdout[2],
              int fderr[2],
              const char *dir,
              int cgi_config_idx)
{
    HANDLE me;
    char *interp;
    char *interp_arg = 0;
    char full_dir[UTF8_PATH_MAX], cmdline[UTF8_PATH_MAX], buf[UTF8_PATH_MAX];
    int truncated;
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    STARTUPINFOA si;
    PROCESS_INFORMATION pi = {0};
 
    (void)envp;
 
    memset(&si, 0, sizeof(si));
    si.cb = sizeof(si);
 
    si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
    si.wShowWindow = SW_HIDE;
 
    me = GetCurrentProcess();
    DuplicateHandle(me,
                    (HANDLE)_get_osfhandle(fdin[0]),
                    me,
                    &si.hStdInput,
                    0,
                    TRUE,
                    DUPLICATE_SAME_ACCESS);
    DuplicateHandle(me,
                    (HANDLE)_get_osfhandle(fdout[1]),
                    me,
                    &si.hStdOutput,
                    0,
                    TRUE,
                    DUPLICATE_SAME_ACCESS);
    DuplicateHandle(me,
                    (HANDLE)_get_osfhandle(fderr[1]),
                    me,
                    &si.hStdError,
                    0,
                    TRUE,
                    DUPLICATE_SAME_ACCESS);
 
    /* Mark handles that should not be inherited. See
     * https://msdn.microsoft.com/en-us/library/windows/desktop/ms682499%28v=vs.85%29.aspx
     */
    SetHandleInformation((HANDLE)_get_osfhandle(fdin[1]),
                         HANDLE_FLAG_INHERIT,
                         0);
    SetHandleInformation((HANDLE)_get_osfhandle(fdout[0]),
                         HANDLE_FLAG_INHERIT,
                         0);
    SetHandleInformation((HANDLE)_get_osfhandle(fderr[0]),
                         HANDLE_FLAG_INHERIT,
                         0);
 
    /* First check, if there is a CGI interpreter configured for all CGI
     * scripts. */
    interp = conn->dom_ctx->config[CGI_INTERPRETER + cgi_config_idx];
    if (interp != NULL) {
        /* If there is a configured interpreter, check for additional arguments
         */
        interp_arg =
            conn->dom_ctx->config[CGI_INTERPRETER_ARGS + cgi_config_idx];
    } else {
        /* Otherwise, the interpreter must be stated in the first line of the
         * CGI script file, after a #! (shebang) mark. */
        buf[0] = buf[1] = '\0';
 
        /* Get the full script path */
        mg_snprintf(
            conn, &truncated, cmdline, sizeof(cmdline), "%s/%s", dir, prog);
 
        if (truncated) {
            pi.hProcess = (pid_t)-1;
            goto spawn_cleanup;
        }
 
        /* Open the script file, to read the first line */
        if (mg_fopen(conn, cmdline, MG_FOPEN_MODE_READ, &file)) {
 
            /* Read the first line of the script into the buffer */
            mg_fgets(buf, sizeof(buf), &file);
            (void)mg_fclose(&file.access); /* ignore error on read only file */
            buf[sizeof(buf) - 1] = '\0';
        }
 
        if ((buf[0] == '#') && (buf[1] == '!')) {
            trim_trailing_whitespaces(buf + 2);
        } else {
            buf[2] = '\0';
        }
        interp = buf + 2;
    }
 
    GetFullPathNameA(dir, sizeof(full_dir), full_dir, NULL);
 
    if (interp[0] != '\0') {
        /* This is an interpreted script file. We must call the interpreter. */
        if ((interp_arg != 0) && (interp_arg[0] != 0)) {
            mg_snprintf(conn,
                        &truncated,
                        cmdline,
                        sizeof(cmdline),
                        "\"%s\" %s \"%s\\%s\"",
                        interp,
                        interp_arg,
                        full_dir,
                        prog);
        } else {
            mg_snprintf(conn,
                        &truncated,
                        cmdline,
                        sizeof(cmdline),
                        "\"%s\" \"%s\\%s\"",
                        interp,
                        full_dir,
                        prog);
        }
    } else {
        /* This is (probably) a compiled program. We call it directly. */
        mg_snprintf(conn,
                    &truncated,
                    cmdline,
                    sizeof(cmdline),
                    "\"%s\\%s\"",
                    full_dir,
                    prog);
    }
 
    if (truncated) {
        pi.hProcess = (pid_t)-1;
        goto spawn_cleanup;
    }
 
    DEBUG_TRACE("Running [%s]", cmdline);
    if (CreateProcessA(NULL,
                       cmdline,
                       NULL,
                       NULL,
                       TRUE,
                       CREATE_NEW_PROCESS_GROUP,
                       envblk,
                       NULL,
                       &si,
                       &pi)
        == 0) {
        mg_cry_internal(
            conn, "%s: CreateProcess(%s): %ld", __func__, cmdline, (long)ERRNO);
        pi.hProcess = (pid_t)-1;
        /* goto spawn_cleanup; */
    }
 
spawn_cleanup:
    (void)CloseHandle(si.hStdOutput);
    (void)CloseHandle(si.hStdError);
    (void)CloseHandle(si.hStdInput);
    if (pi.hThread != NULL) {
        (void)CloseHandle(pi.hThread);
    }
 
    return (pid_t)pi.hProcess;
}
#endif /* !NO_CGI */
 
 
static int
set_blocking_mode(SOCKET sock)
{
    unsigned long non_blocking = 0;
    return ioctlsocket(sock, (long)FIONBIO, &non_blocking);
}
 
 
static int
set_non_blocking_mode(SOCKET sock)
{
    unsigned long non_blocking = 1;
    return ioctlsocket(sock, (long)FIONBIO, &non_blocking);
}
 
 
#else
 
 
#if !defined(NO_FILESYSTEMS)
static int
mg_stat(const struct mg_connection *conn,
        const char *path,
        struct mg_file_stat *filep)
{
    struct stat st;
    if (!filep) {
        return 0;
    }
    memset(filep, 0, sizeof(*filep));
 
    if (mg_path_suspicious(conn, path)) {
        return 0;
    }
 
    if (0 == stat(path, &st)) {
        filep->size = (uint64_t)(st.st_size);
        filep->last_modified = st.st_mtime;
        filep->is_directory = S_ISDIR(st.st_mode);
        return 1;
    }
 
    return 0;
}
#endif /* NO_FILESYSTEMS */
 
 
static void
set_close_on_exec(int fd,
                  const struct mg_connection *conn /* may be null */,
                  struct mg_context *ctx /* may be null */)
{
#if defined(__ZEPHYR__)
    (void)fd;
    (void)conn;
    (void)ctx;
#else
    if (fcntl(fd, F_SETFD, FD_CLOEXEC) != 0) {
        if (conn || ctx) {
            struct mg_connection fc;
            mg_cry_internal((conn ? conn : fake_connection(&fc, ctx)),
                            "%s: fcntl(F_SETFD FD_CLOEXEC) failed: %s",
                            __func__,
                            strerror(ERRNO));
        }
    }
#endif
}
 
 
CIVETWEB_API int
mg_start_thread(mg_thread_func_t func, void *param)
{
    pthread_t thread_id;
    pthread_attr_t attr;
    int result;
 
    (void)pthread_attr_init(&attr);
    (void)pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 
#if defined(__ZEPHYR__)
    pthread_attr_setstack(&attr, &civetweb_main_stack, ZEPHYR_STACK_SIZE);
#elif defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
    /* Compile-time option to control stack size,
     * e.g. -DUSE_STACK_SIZE=16384 */
    (void)pthread_attr_setstacksize(&attr, USE_STACK_SIZE);
#endif /* defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1) */
 
    result = pthread_create(&thread_id, &attr, func, param);
    pthread_attr_destroy(&attr);
 
    return result;
}
 
 
/* Start a thread storing the thread context. */
static int
mg_start_thread_with_id(mg_thread_func_t func,
                        void *param,
                        pthread_t *threadidptr)
{
    pthread_t thread_id;
    pthread_attr_t attr;
    int result;
 
    (void)pthread_attr_init(&attr);
 
#if defined(__ZEPHYR__)
    pthread_attr_setstack(&attr,
                          &civetweb_worker_stacks[zephyr_worker_stack_index++],
                          ZEPHYR_STACK_SIZE);
#elif defined(USE_STACK_SIZE) && (USE_STACK_SIZE > 1)
    /* Compile-time option to control stack size,
     * e.g. -DUSE_STACK_SIZE=16384 */
    (void)pthread_attr_setstacksize(&attr, USE_STACK_SIZE);
#endif /* defined(USE_STACK_SIZE) && USE_STACK_SIZE > 1 */
 
    result = pthread_create(&thread_id, &attr, func, param);
    pthread_attr_destroy(&attr);
    if ((result == 0) && (threadidptr != NULL)) {
        *threadidptr = thread_id;
    }
    return result;
}
 
 
/* Wait for a thread to finish. */
static int
mg_join_thread(pthread_t threadid)
{
    int result;
 
    result = pthread_join(threadid, NULL);
    return result;
}
 
 
#if !defined(NO_CGI)
static pid_t
spawn_process(struct mg_connection *conn,
              const char *prog,
              char *envblk,
              char *envp[],
              int fdin[2],
              int fdout[2],
              int fderr[2],
              const char *dir,
              int cgi_config_idx)
{
    pid_t pid;
    const char *interp;
 
    (void)envblk;
 
    if ((pid = fork()) == -1) {
        /* Parent */
        mg_cry_internal(conn, "%s: fork(): %s", __func__, strerror(ERRNO));
    } else if (pid != 0) {
        /* Make sure children close parent-side descriptors.
         * The caller will close the child-side immediately. */
        set_close_on_exec(fdin[1], conn, NULL);  /* stdin write */
        set_close_on_exec(fdout[0], conn, NULL); /* stdout read */
        set_close_on_exec(fderr[0], conn, NULL); /* stderr read */
    } else {
        /* Child */
        if (chdir(dir) != 0) {
            mg_cry_internal(
                conn, "%s: chdir(%s): %s", __func__, dir, strerror(ERRNO));
        } else if (dup2(fdin[0], 0) == -1) {
            mg_cry_internal(conn,
                            "%s: dup2(%d, 0): %s",
                            __func__,
                            fdin[0],
                            strerror(ERRNO));
        } else if (dup2(fdout[1], 1) == -1) {
            mg_cry_internal(conn,
                            "%s: dup2(%d, 1): %s",
                            __func__,
                            fdout[1],
                            strerror(ERRNO));
        } else if (dup2(fderr[1], 2) == -1) {
            mg_cry_internal(conn,
                            "%s: dup2(%d, 2): %s",
                            __func__,
                            fderr[1],
                            strerror(ERRNO));
        } else {
            struct sigaction sa;
 
            /* Keep stderr and stdout in two different pipes.
             * Stdout will be sent back to the client,
             * stderr should go into a server error log. */
            (void)close(fdin[0]);
            (void)close(fdout[1]);
            (void)close(fderr[1]);
 
            /* Close write end fdin and read end fdout and fderr */
            (void)close(fdin[1]);
            (void)close(fdout[0]);
            (void)close(fderr[0]);
 
            /* After exec, all signal handlers are restored to their default
             * values, with one exception of SIGCHLD. According to
             * POSIX.1-2001 and Linux's implementation, SIGCHLD's handler
             * will leave unchanged after exec if it was set to be ignored.
             * Restore it to default action. */
            memset(&sa, 0, sizeof(sa));
            sa.sa_handler = SIG_DFL;
            sigaction(SIGCHLD, &sa, NULL);
 
            interp = conn->dom_ctx->config[CGI_INTERPRETER + cgi_config_idx];
            if (interp == NULL) {
                /* no interpreter configured, call the program directly */
                (void)execle(prog, prog, NULL, envp);
                mg_cry_internal(conn,
                                "%s: execle(%s): %s",
                                __func__,
                                prog,
                                strerror(ERRNO));
            } else {
                /* call the configured interpreter */
                const char *interp_args =
                    conn->dom_ctx
                        ->config[CGI_INTERPRETER_ARGS + cgi_config_idx];
 
                if ((interp_args != NULL) && (interp_args[0] != 0)) {
                    (void)execle(interp, interp, interp_args, prog, NULL, envp);
                } else {
                    (void)execle(interp, interp, prog, NULL, envp);
                }
                mg_cry_internal(conn,
                                "%s: execle(%s %s): %s",
                                __func__,
                                interp,
                                prog,
                                strerror(ERRNO));
            }
        }
        exit(EXIT_FAILURE);
    }
 
    return pid;
}
#endif /* !NO_CGI */
 
 
static int
set_non_blocking_mode(SOCKET sock)
{
    int flags = fcntl(sock, F_GETFL, 0);
    if (flags < 0) {
        return -1;
    }
 
    if (fcntl(sock, F_SETFL, (flags | O_NONBLOCK)) < 0) {
        return -1;
    }
    return 0;
}
 
static int
set_blocking_mode(SOCKET sock)
{
    int flags = fcntl(sock, F_GETFL, 0);
    if (flags < 0) {
        return -1;
    }
 
    if (fcntl(sock, F_SETFL, flags & (~(int)(O_NONBLOCK))) < 0) {
        return -1;
    }
    return 0;
}
#endif /* _WIN32 / else */
 
/* End of initial operating system specific define block. */
 
 
/* Get a random number (independent of C rand function) */
static uint64_t
get_random(void)
{
    static uint64_t lfsr = 0; /* Linear feedback shift register */
    static uint64_t lcg = 0;  /* Linear congruential generator */
    uint64_t now = mg_get_current_time_ns();
 
    if (lfsr == 0) {
        /* lfsr will be only 0 if has not been initialized,
         * so this code is called only once. */
        lfsr = mg_get_current_time_ns();
        lcg = mg_get_current_time_ns();
    } else {
        /* Get the next step of both random number generators. */
        lfsr = (lfsr >> 1)
               | ((((lfsr >> 0) ^ (lfsr >> 1) ^ (lfsr >> 3) ^ (lfsr >> 4)) & 1)
                  << 63);
        lcg = lcg * 6364136223846793005LL + 1442695040888963407LL;
    }
 
    /* Combining two pseudo-random number generators and a high resolution
     * part
     * of the current server time will make it hard (impossible?) to guess
     * the
     * next number. */
    return (lfsr ^ lcg ^ now);
}
 
 
static int
mg_poll(struct mg_pollfd *pfd,
        unsigned int n,
        int milliseconds,
        const stop_flag_t *stop_flag)
{
    /* Call poll, but only for a maximum time of a few seconds.
     * This will allow to stop the server after some seconds, instead
     * of having to wait for a long socket timeout. */
    int ms_now = SOCKET_TIMEOUT_QUANTUM; /* Sleep quantum in ms */
 
    int check_pollerr = 0;
    if ((n == 1) && ((pfd[0].events & POLLERR) == 0)) {
        /* If we wait for only one file descriptor, wait on error as well */
        pfd[0].events |= POLLERR;
        check_pollerr = 1;
    }
 
    do {
        int result;
 
        if (!STOP_FLAG_IS_ZERO(&*stop_flag)) {
            /* Shut down signal */
            return -2;
        }
 
        if ((milliseconds >= 0) && (milliseconds < ms_now)) {
            ms_now = milliseconds;
        }
 
        result = poll(pfd, n, ms_now);
        if (result != 0) {
            int err = ERRNO;
            if ((result == 1) || (!ERROR_TRY_AGAIN(err))) {
                /* Poll returned either success (1) or error (-1).
                 * Forward both to the caller. */
                if ((check_pollerr)
                    && ((pfd[0].revents & (POLLIN | POLLOUT | POLLERR))
                        == POLLERR)) {
                    /* One and only file descriptor returned error */
                    return -1;
                }
                return result;
            }
        }
 
        /* Poll returned timeout (0). */
        if (milliseconds > 0) {
            milliseconds -= ms_now;
        }
 
    } while (milliseconds > 0);
 
    /* timeout: return 0 */
    return 0;
}
 
 
/* Write data to the IO channel - opened file descriptor, socket or SSL
 * descriptor.
 * Return value:
 *  >=0 .. number of bytes successfully written
 *   -1 .. timeout
 *   -2 .. error
 */
static int
push_inner(struct mg_context *ctx,
           FILE *fp,
           SOCKET sock,
           SSL *ssl,
           const char *buf,
           int len,
           double timeout)
{
    uint64_t start = 0, now = 0, timeout_ns = 0;
    int n, err;
    unsigned ms_wait = SOCKET_TIMEOUT_QUANTUM; /* Sleep quantum in ms */
 
#if defined(_WIN32)
    typedef int len_t;
#else
    typedef size_t len_t;
#endif
 
    if (timeout > 0) {
        now = mg_get_current_time_ns();
        start = now;
        timeout_ns = (uint64_t)(timeout * 1.0E9);
    }
 
    if (ctx == NULL) {
        return -2;
    }
 
#if defined(NO_SSL) && !defined(USE_MBEDTLS)
    if (ssl) {
        return -2;
    }
#endif
 
    /* Try to read until it succeeds, fails, times out, or the server
     * shuts down. */
    for (;;) {
 
#if defined(USE_MBEDTLS)
        if (ssl != NULL) {
            n = mbed_ssl_write(ssl, (const unsigned char *)buf, len);
            if (n <= 0) {
                if ((n == MBEDTLS_ERR_SSL_WANT_READ)
                    || (n == MBEDTLS_ERR_SSL_WANT_WRITE)
                    || n == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
                    n = 0;
                } else {
                    fprintf(stderr, "SSL write failed, error %d\n", n);
                    return -2;
                }
            } else {
                err = 0;
            }
        } else
#elif !defined(NO_SSL)
        if (ssl != NULL) {
            ERR_clear_error();
            n = SSL_write(ssl, buf, len);
            if (n <= 0) {
                err = SSL_get_error(ssl, n);
                if ((err == SSL_ERROR_SYSCALL) && (n == -1)) {
                    err = ERRNO;
                } else if ((err == SSL_ERROR_WANT_READ)
                           || (err == SSL_ERROR_WANT_WRITE)) {
                    n = 0;
                } else {
                    DEBUG_TRACE("SSL_write() failed, error %d", err);
                    ERR_clear_error();
                    return -2;
                }
                ERR_clear_error();
            } else {
                err = 0;
            }
        } else
#endif
 
            if (fp != NULL) {
            n = (int)fwrite(buf, 1, (size_t)len, fp);
            if (ferror(fp)) {
                n = -1;
                err = ERRNO;
            } else {
                err = 0;
            }
        } else {
            n = (int)send(sock, buf, (len_t)len, MSG_NOSIGNAL);
            err = (n < 0) ? ERRNO : 0;
            if (ERROR_TRY_AGAIN(err)) {
                err = 0;
                n = 0;
            }
            if (n < 0) {
                /* shutdown of the socket at client side */
                return -2;
            }
        }
 
        if (!STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
            return -2;
        }
 
        if ((n > 0) || ((n == 0) && (len == 0))) {
            /* some data has been read, or no data was requested */
            return n;
        }
        if (n < 0) {
            /* socket error - check errno */
            DEBUG_TRACE("send() failed, error %d", err);
 
            /* TODO (mid): error handling depending on the error code.
             * These codes are different between Windows and Linux.
             * Currently there is no problem with failing send calls,
             * if there is a reproducible situation, it should be
             * investigated in detail.
             */
            return -2;
        }
 
        /* Only in case n=0 (timeout), repeat calling the write function */
 
        /* If send failed, wait before retry */
        if (fp != NULL) {
            /* For files, just wait a fixed time.
             * Maybe it helps, maybe not. */
            mg_sleep(5);
        } else {
            /* For sockets, wait for the socket using poll */
            struct mg_pollfd pfd[1];
            int pollres;
 
            pfd[0].fd = sock;
            pfd[0].events = POLLOUT;
            pollres = mg_poll(pfd, 1, (int)(ms_wait), &(ctx->stop_flag));
            if (!STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
                return -2;
            }
            if (pollres > 0) {
                continue;
            }
        }
 
        if (timeout > 0) {
            now = mg_get_current_time_ns();
            if ((now - start) > timeout_ns) {
                /* Timeout */
                break;
            }
        }
    }
 
    (void)err; /* Avoid unused warning if NO_SSL is set and DEBUG_TRACE is not
               used */
 
    return -1;
}
 
 
static int
push_all(struct mg_context *ctx,
         FILE *fp,
         SOCKET sock,
         SSL *ssl,
         const char *buf,
         int len)
{
    double timeout = -1.0;
    int n, nwritten = 0;
 
    if (ctx == NULL) {
        return -1;
    }
 
    if (ctx->dd.config[REQUEST_TIMEOUT]) {
        timeout = atoi(ctx->dd.config[REQUEST_TIMEOUT]) / 1000.0;
    }
    if (timeout <= 0.0) {
        timeout = strtod(config_options[REQUEST_TIMEOUT].default_value, NULL)
                  / 1000.0;
    }
 
    while ((len > 0) && STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
        n = push_inner(ctx, fp, sock, ssl, buf + nwritten, len, timeout);
        if (n < 0) {
            if (nwritten == 0) {
                nwritten = -1; /* Propagate the error */
            }
            break;
        } else if (n == 0) {
            break; /* No more data to write */
        } else {
            nwritten += n;
            len -= n;
        }
    }
 
    return nwritten;
}
 
 
/* Read from IO channel - opened file descriptor, socket, or SSL descriptor.
 * Return value:
 *  >=0 .. number of bytes successfully read
 *   -1 .. timeout
 *   -2 .. error
 */
static int
pull_inner(FILE *fp,
           struct mg_connection *conn,
           char *buf,
           int len,
           double timeout)
{
    int nread, err = 0;
 
#if defined(_WIN32)
    typedef int len_t;
#else
    typedef size_t len_t;
#endif
 
    /* We need an additional wait loop around this, because in some cases
     * with TLSwe may get data from the socket but not from SSL_read.
     * In this case we need to repeat at least once.
     */
 
    if (fp != NULL) {
        /* Use read() instead of fread(), because if we're reading from the
         * CGI pipe, fread() may block until IO buffer is filled up. We
         * cannot afford to block and must pass all read bytes immediately
         * to the client. */
        nread = (int)read(fileno(fp), buf, (size_t)len);
 
        err = (nread < 0) ? ERRNO : 0;
        if ((nread == 0) && (len > 0)) {
            /* Should get data, but got EOL */
            return -2;
        }
 
#if defined(USE_MBEDTLS)
    } else if (conn->ssl != NULL) {
        struct mg_pollfd pfd[1];
        int to_read;
        int pollres;
 
        to_read = mbedtls_ssl_get_bytes_avail(conn->ssl);
 
        if (to_read > 0) {
            /* We already know there is no more data buffered in conn->buf
             * but there is more available in the SSL layer. So don't poll
             * conn->client.sock yet. */
 
            pollres = 1;
            if (to_read > len)
                to_read = len;
        } else {
            pfd[0].fd = conn->client.sock;
            pfd[0].events = POLLIN;
 
            to_read = len;
 
            pollres = mg_poll(pfd,
                              1,
                              (int)(timeout * 1000.0),
                              &(conn->phys_ctx->stop_flag));
 
            if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
                return -2;
            }
        }
 
        if (pollres > 0) {
            nread = mbed_ssl_read(conn->ssl, (unsigned char *)buf, to_read);
            if (nread <= 0) {
                if ((nread == MBEDTLS_ERR_SSL_WANT_READ)
                    || (nread == MBEDTLS_ERR_SSL_WANT_WRITE)
                    || nread == MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) {
                    nread = 0;
                } else {
                    fprintf(stderr, "SSL read failed, error %d\n", nread);
                    return -2;
                }
            } else {
                err = 0;
            }
 
        } else if (pollres < 0) {
            /* Error */
            return -2;
        } else {
            /* pollres = 0 means timeout */
            nread = 0;
        }
 
#elif !defined(NO_SSL)
    } else if (conn->ssl != NULL) {
        int ssl_pending;
        struct mg_pollfd pfd[1];
        int pollres;
 
        if ((ssl_pending = SSL_pending(conn->ssl)) > 0) {
            /* We already know there is no more data buffered in conn->buf
             * but there is more available in the SSL layer. So don't poll
             * conn->client.sock yet. */
            if (ssl_pending > len) {
                ssl_pending = len;
            }
            pollres = 1;
        } else {
            pfd[0].fd = conn->client.sock;
            pfd[0].events = POLLIN;
            pollres = mg_poll(pfd,
                              1,
                              (int)(timeout * 1000.0),
                              &(conn->phys_ctx->stop_flag));
            if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
                return -2;
            }
        }
        if (pollres > 0) {
            ERR_clear_error();
            nread =
                SSL_read(conn->ssl, buf, (ssl_pending > 0) ? ssl_pending : len);
            if (nread <= 0) {
                err = SSL_get_error(conn->ssl, nread);
                if ((err == SSL_ERROR_SYSCALL) && (nread == -1)) {
                    err = ERRNO;
                } else if ((err == SSL_ERROR_WANT_READ)
                           || (err == SSL_ERROR_WANT_WRITE)) {
                    nread = 0;
                } else {
                    /* All errors should return -2 */
                    DEBUG_TRACE("SSL_read() failed, error %d", err);
                    ERR_clear_error();
                    return -2;
                }
                ERR_clear_error();
            } else {
                err = 0;
            }
        } else if (pollres < 0) {
            /* Error */
            return -2;
        } else {
            /* pollres = 0 means timeout */
            nread = 0;
        }
#endif
 
    } else {
        struct mg_pollfd pfd[1];
        int pollres;
 
        pfd[0].fd = conn->client.sock;
        pfd[0].events = POLLIN;
        pollres = mg_poll(pfd,
                          1,
                          (int)(timeout * 1000.0),
                          &(conn->phys_ctx->stop_flag));
        if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
            return -2;
        }
        if (pollres > 0) {
            nread = (int)recv(conn->client.sock, buf, (len_t)len, 0);
            err = (nread < 0) ? ERRNO : 0;
            if (nread <= 0) {
                /* shutdown of the socket at client side */
                return -2;
            }
        } else if (pollres < 0) {
            /* error calling poll */
            return -2;
        } else {
            /* pollres = 0 means timeout */
            nread = 0;
        }
    }
 
    if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
        return -2;
    }
 
    if ((nread > 0) || ((nread == 0) && (len == 0))) {
        /* some data has been read, or no data was requested */
        return nread;
    }
 
    if (nread < 0) {
        /* socket error - check errno */
#if defined(_WIN32)
        if (err == WSAEWOULDBLOCK) {
            /* TODO (low): check if this is still required */
            /* standard case if called from close_socket_gracefully */
            return -2;
        } else if (err == WSAETIMEDOUT) {
            /* TODO (low): check if this is still required */
            /* timeout is handled by the while loop  */
            return 0;
        } else if (err == WSAECONNABORTED) {
            /* See https://www.chilkatsoft.com/p/p_299.asp */
            return -2;
        } else {
            DEBUG_TRACE("recv() failed, error %d", err);
            return -2;
        }
#else
        /* TODO: POSIX returns either EAGAIN or EWOULDBLOCK in both cases,
         * if the timeout is reached and if the socket was set to non-
         * blocking in close_socket_gracefully, so we can not distinguish
         * here. We have to wait for the timeout in both cases for now.
         */
        if (ERROR_TRY_AGAIN(err)) {
            /* TODO (low): check if this is still required */
            /* EAGAIN/EWOULDBLOCK:
             * standard case if called from close_socket_gracefully
             * => should return -1 */
            /* or timeout occurred
             * => the code must stay in the while loop */
 
            /* EINTR can be generated on a socket with a timeout set even
             * when SA_RESTART is effective for all relevant signals
             * (see signal(7)).
             * => stay in the while loop */
        } else {
            DEBUG_TRACE("recv() failed, error %d", err);
            return -2;
        }
#endif
    }
 
    /* Timeout occurred, but no data available. */
    return -1;
}
 
 
static int
pull_all(FILE *fp, struct mg_connection *conn, char *buf, int len)
{
    int n, nread = 0;
    double timeout = -1.0;
    uint64_t start_time = 0, now = 0, timeout_ns = 0;
 
    if (conn->dom_ctx->config[REQUEST_TIMEOUT]) {
        timeout = atoi(conn->dom_ctx->config[REQUEST_TIMEOUT]) / 1000.0;
    }
    if (timeout <= 0.0) {
        timeout = strtod(config_options[REQUEST_TIMEOUT].default_value, NULL)
                  / 1000.0;
    }
    start_time = mg_get_current_time_ns();
    timeout_ns = (uint64_t)(timeout * 1.0E9);
 
    while ((len > 0) && STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
        n = pull_inner(fp, conn, buf + nread, len, timeout);
        if (n == -2) {
            if (nread == 0) {
                nread = -1; /* Propagate the error */
            }
            break;
        } else if (n == -1) {
            /* timeout */
            if (timeout >= 0.0) {
                now = mg_get_current_time_ns();
                if ((now - start_time) <= timeout_ns) {
                    continue;
                }
            }
            break;
        } else if (n == 0) {
            break; /* No more data to read */
        } else {
            nread += n;
            len -= n;
        }
    }
 
    return nread;
}
 
 
static void
discard_unread_request_data(struct mg_connection *conn)
{
    char buf[MG_BUF_LEN];
 
    while (mg_read(conn, buf, sizeof(buf)) > 0)
        ;
}
 
 
static int
mg_read_inner(struct mg_connection *conn, void *buf, size_t len)
{
    int64_t content_len, n, buffered_len, nread;
    int64_t len64 =
        (int64_t)((len > INT_MAX) ? INT_MAX : len); /* since the return value is
                                                     * int, we may not read more
                                                     * bytes */
    const char *body;
 
    if (conn == NULL) {
        return 0;
    }
 
    /* If Content-Length is not set for a response with body data,
     * we do not know in advance how much data should be read. */
    content_len = conn->content_len;
    if (content_len < 0) {
        /* The body data is completed when the connection is closed. */
        content_len = INT64_MAX;
    }
 
    nread = 0;
    if (conn->consumed_content < content_len) {
        /* Adjust number of bytes to read. */
        int64_t left_to_read = content_len - conn->consumed_content;
        if (left_to_read < len64) {
            /* Do not read more than the total content length of the
             * request.
             */
            len64 = left_to_read;
        }
 
        /* Return buffered data */
        buffered_len = (int64_t)(conn->data_len) - (int64_t)conn->request_len
                       - conn->consumed_content;
        if (buffered_len > 0) {
            if (len64 < buffered_len) {
                buffered_len = len64;
            }
            body = conn->buf + conn->request_len + conn->consumed_content;
            memcpy(buf, body, (size_t)buffered_len);
            len64 -= buffered_len;
            conn->consumed_content += buffered_len;
            nread += buffered_len;
            buf = (char *)buf + buffered_len;
        }
 
        /* We have returned all buffered data. Read new data from the remote
         * socket.
         */
        if ((n = pull_all(NULL, conn, (char *)buf, (int)len64)) >= 0) {
            conn->consumed_content += n;
            nread += n;
        } else {
            nread = ((nread > 0) ? nread : n);
        }
    }
    return (int)nread;
}
 
 
/* Forward declarations */
static void handle_request(struct mg_connection *);
static void log_access(const struct mg_connection *);
 
 
/* Handle request, update statistics and call access log */
static void
handle_request_stat_log(struct mg_connection *conn)
{
#if defined(USE_SERVER_STATS)
    struct timespec tnow;
    conn->conn_state = 4; /* processing */
#endif
 
    handle_request(conn);
 
 
#if defined(USE_SERVER_STATS)
    conn->conn_state = 5; /* processed */
 
    clock_gettime(CLOCK_MONOTONIC, &tnow);
    conn->processing_time = mg_difftimespec(&tnow, &(conn->req_time));
 
    mg_atomic_add64(&(conn->phys_ctx->total_data_read), conn->consumed_content);
    mg_atomic_add64(&(conn->phys_ctx->total_data_written),
                    conn->num_bytes_sent);
#endif
 
    DEBUG_TRACE("%s", "handle_request done");
 
    if (conn->phys_ctx->callbacks.end_request != NULL) {
        conn->phys_ctx->callbacks.end_request(conn, conn->status_code);
        DEBUG_TRACE("%s", "end_request callback done");
    }
    log_access(conn);
}
 
 
#if defined(USE_HTTP2)
#if defined(NO_SSL)
#error "HTTP2 requires ALPN, ALPN requires SSL/TLS"
#endif
#define USE_ALPN
#include "http2.inl"
/* Not supported with HTTP/2 */
#define HTTP1_only                                                             \
    {                                                                          \
        if (conn->protocol_type == PROTOCOL_TYPE_HTTP2) {                      \
            http2_must_use_http1(conn);                                        \
            DEBUG_TRACE("%s", "must use HTTP/1.x");                            \
            return;                                                            \
        }                                                                      \
    }
#else
#define HTTP1_only
#endif
 
 
CIVETWEB_API int
mg_read(struct mg_connection *conn, void *buf, size_t len)
{
    if (len > INT_MAX) {
        len = INT_MAX;
    }
 
    if (conn == NULL) {
        return 0;
    }
 
    if (conn->is_chunked) {
        size_t all_read = 0;
 
        while (len > 0) {
            if (conn->is_chunked >= 3) {
                /* No more data left to read */
                return 0;
            }
            if (conn->is_chunked != 1) {
                /* Has error */
                return -1;
            }
 
            if (conn->consumed_content != conn->content_len) {
                /* copy from the current chunk */
                int read_ret = mg_read_inner(conn, (char *)buf + all_read, len);
 
                if (read_ret < 1) {
                    /* read error */
                    conn->is_chunked = 2;
                    return -1;
                }
 
                all_read += (size_t)read_ret;
                len -= (size_t)read_ret;
 
                if (conn->consumed_content == conn->content_len) {
                    /* Add data bytes in the current chunk have been read,
                     * so we are expecting \r\n now. */
                    char x[2];
                    conn->content_len += 2;
                    if ((mg_read_inner(conn, x, 2) != 2) || (x[0] != '\r')
                        || (x[1] != '\n')) {
                        /* Protocol violation */
                        conn->is_chunked = 2;
                        return -1;
                    }
                }
 
            } else {
                /* fetch a new chunk */
                size_t i;
                char lenbuf[64];
                char *end = NULL;
                unsigned long chunkSize = 0;
 
                for (i = 0; i < (sizeof(lenbuf) - 1); i++) {
                    conn->content_len++;
                    if (mg_read_inner(conn, lenbuf + i, 1) != 1) {
                        lenbuf[i] = 0;
                    }
                    if ((i > 0) && (lenbuf[i] == ';')) {
                        // chunk extension --> skip chars until next CR
                        //
                        // RFC 2616, 3.6.1 Chunked Transfer Coding
                        // (https://www.rfc-editor.org/rfc/rfc2616#page-25)
                        //
                        // chunk          = chunk-size [ chunk-extension ] CRLF
                        //                  chunk-data CRLF
                        // ...
                        // chunk-extension= *( ";" chunk-ext-name [ "="
                        // chunk-ext-val ] )
                        do
                            ++conn->content_len;
                        while (mg_read_inner(conn, lenbuf + i, 1) == 1
                               && lenbuf[i] != '\r');
                    }
                    if ((i > 0) && (lenbuf[i] == '\r')
                        && (lenbuf[i - 1] != '\r')) {
                        continue;
                    }
                    if ((i > 1) && (lenbuf[i] == '\n')
                        && (lenbuf[i - 1] == '\r')) {
                        lenbuf[i + 1] = 0;
                        chunkSize = strtoul(lenbuf, &end, 16);
                        if (chunkSize == 0) {
                            /* regular end of content */
                            conn->is_chunked = 3;
                        }
                        break;
                    }
                    if (!isxdigit((unsigned char)lenbuf[i])) {
                        /* illegal character for chunk length */
                        conn->is_chunked = 2;
                        return -1;
                    }
                }
                if ((end == NULL) || (*end != '\r')) {
                    /* chunksize not set correctly */
                    conn->is_chunked = 2;
                    return -1;
                }
                if (conn->is_chunked == 3) {
                    /* try discarding trailer for keep-alive */
 
                    // We found the last chunk (length 0) including the
                    // CRLF that terminates that chunk. Now follows a possibly
                    // empty trailer and a final CRLF.
                    //
                    // see RFC 2616, 3.6.1 Chunked Transfer Coding
                    // (https://www.rfc-editor.org/rfc/rfc2616#page-25)
                    //
                    // Chunked-Body   = *chunk
                    //                  last-chunk
                    //                  trailer
                    //                  CRLF
                    // ...
                    // last-chunk     = 1*("0") [ chunk-extension ] CRLF
                    // ...
                    // trailer        = *(entity-header CRLF)
 
                    int crlf_count = 2; // one CRLF already determined
 
                    while (crlf_count < 4 && conn->is_chunked == 3) {
                        ++conn->content_len;
                        if (mg_read_inner(conn, lenbuf, 1) == 1) {
                            if ((crlf_count == 0 || crlf_count == 2)) {
                                if (lenbuf[0] == '\r')
                                    ++crlf_count;
                                else
                                    crlf_count = 0;
                            } else {
                                // previous character was a CR
                                // --> next character must be LF
 
                                if (lenbuf[0] == '\n')
                                    ++crlf_count;
                                else
                                    conn->is_chunked = 2;
                            }
                        } else
                            // premature end of trailer
                            conn->is_chunked = 2;
                    }
 
                    if (conn->is_chunked == 2)
                        return -1;
                    else
                        conn->is_chunked = 4;
 
                    break;
                }
 
                /* append a new chunk */
                conn->content_len += (int64_t)chunkSize;
            }
        }
 
        return (int)all_read;
    }
    return mg_read_inner(conn, buf, len);
}
 
 
CIVETWEB_API int
mg_write(struct mg_connection *conn, const void *buf, size_t len)
{
    time_t now;
    int n, total, allowed;
 
    if (conn == NULL) {
        return 0;
    }
    if (len > INT_MAX) {
        return -1;
    }
 
    /* Mark connection as "data sent" */
    conn->request_state = 10;
#if defined(USE_HTTP2)
    if (conn->protocol_type == PROTOCOL_TYPE_HTTP2) {
        http2_data_frame_head(conn, len, 0);
    }
#endif
 
    if (conn->throttle > 0) {
        if ((now = time(NULL)) != conn->last_throttle_time) {
            conn->last_throttle_time = now;
            conn->last_throttle_bytes = 0;
        }
        allowed = conn->throttle - conn->last_throttle_bytes;
        if (allowed > (int)len) {
            allowed = (int)len;
        }
 
        total = push_all(conn->phys_ctx,
                         NULL,
                         conn->client.sock,
                         conn->ssl,
                         (const char *)buf,
                         allowed);
 
        if (total == allowed) {
 
            buf = (const char *)buf + total;
            conn->last_throttle_bytes += total;
            while ((total < (int)len)
                   && STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
                allowed = (conn->throttle > ((int)len - total))
                              ? (int)len - total
                              : conn->throttle;
 
                n = push_all(conn->phys_ctx,
                             NULL,
                             conn->client.sock,
                             conn->ssl,
                             (const char *)buf,
                             allowed);
 
                if (n != allowed) {
                    break;
                }
                sleep(1);
                conn->last_throttle_bytes = allowed;
                conn->last_throttle_time = time(NULL);
                buf = (const char *)buf + n;
                total += n;
            }
        }
    } else {
        total = push_all(conn->phys_ctx,
                         NULL,
                         conn->client.sock,
                         conn->ssl,
                         (const char *)buf,
                         (int)len);
    }
    if (total > 0) {
        conn->num_bytes_sent += total;
    }
    return total;
}
 
 
/* Send a chunk, if "Transfer-Encoding: chunked" is used */
CIVETWEB_API int
mg_send_chunk(struct mg_connection *conn,
              const char *chunk,
              unsigned int chunk_len)
{
    char lenbuf[16];
    size_t lenbuf_len;
    int ret;
    int t;
 
    /* First store the length information in a text buffer. */
    sprintf(lenbuf, "%x\r\n", chunk_len);
    lenbuf_len = strlen(lenbuf);
 
    /* Then send length information, chunk and terminating \r\n. */
    ret = mg_write(conn, lenbuf, lenbuf_len);
    if (ret != (int)lenbuf_len) {
        return -1;
    }
    t = ret;
 
    ret = mg_write(conn, chunk, chunk_len);
    if (ret != (int)chunk_len) {
        return -1;
    }
    t += ret;
 
    ret = mg_write(conn, "\r\n", 2);
    if (ret != 2) {
        return -1;
    }
    t += ret;
 
    return t;
}
 
 
#if defined(GCC_DIAGNOSTIC)
/* This block forwards format strings to printf implementations,
 * so we need to disable the format-nonliteral warning. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
#endif
 
 
/* Alternative alloc_vprintf() for non-compliant C runtimes */
static int
alloc_vprintf2(char **buf, const char *fmt, va_list ap)
{
    va_list ap_copy;
    size_t size = MG_BUF_LEN / 4;
    int len = -1;
 
    *buf = NULL;
    while (len < 0) {
        if (*buf) {
            mg_free(*buf);
        }
 
        size *= 4;
        *buf = (char *)mg_malloc(size);
        if (!*buf) {
            break;
        }
 
        va_copy(ap_copy, ap);
        len = vsnprintf_impl(*buf, size - 1, fmt, ap_copy);
        va_end(ap_copy);
        (*buf)[size - 1] = 0;
    }
 
    return len;
}
 
 
/* Print message to buffer. If buffer is large enough to hold the message,
 * return buffer. If buffer is to small, allocate large enough buffer on
 * heap,
 * and return allocated buffer. */
static int
alloc_vprintf(char **out_buf,
              char *prealloc_buf,
              size_t prealloc_size,
              const char *fmt,
              va_list ap)
{
    va_list ap_copy;
    int len;
 
    /* Windows is not standard-compliant, and vsnprintf() returns -1 if
     * buffer is too small. Also, older versions of msvcrt.dll do not have
     * _vscprintf().  However, if size is 0, vsnprintf() behaves correctly.
     * Therefore, we make two passes: on first pass, get required message
     * length.
     * On second pass, actually print the message. */
    va_copy(ap_copy, ap);
    len = vsnprintf_impl(NULL, 0, fmt, ap_copy);
    va_end(ap_copy);
 
    if (len < 0) {
        /* C runtime is not standard compliant, vsnprintf() returned -1.
         * Switch to alternative code path that uses incremental
         * allocations.
         */
        va_copy(ap_copy, ap);
        len = alloc_vprintf2(out_buf, fmt, ap_copy);
        va_end(ap_copy);
 
    } else if ((size_t)(len) >= prealloc_size) {
        /* The pre-allocated buffer not large enough. */
        /* Allocate a new buffer. */
        *out_buf = (char *)mg_malloc((size_t)(len) + 1);
        if (!*out_buf) {
            /* Allocation failed. Return -1 as "out of memory" error. */
            return -1;
        }
        /* Buffer allocation successful. Store the string there. */
        va_copy(ap_copy, ap);
        IGNORE_UNUSED_RESULT(
            vsnprintf_impl(*out_buf, (size_t)(len) + 1, fmt, ap_copy));
        va_end(ap_copy);
 
    } else {
        /* The pre-allocated buffer is large enough.
         * Use it to store the string and return the address. */
        va_copy(ap_copy, ap);
        IGNORE_UNUSED_RESULT(
            vsnprintf_impl(prealloc_buf, prealloc_size, fmt, ap_copy));
        va_end(ap_copy);
        *out_buf = prealloc_buf;
    }
 
    return len;
}
 
 
static int
alloc_printf(char **out_buf, const char *fmt, ...)
{
    va_list ap;
    int result;
 
    va_start(ap, fmt);
    result = alloc_vprintf(out_buf, NULL, 0, fmt, ap);
    va_end(ap);
 
    return result;
}
 
 
#if defined(GCC_DIAGNOSTIC)
/* Enable format-nonliteral warning again. */
#pragma GCC diagnostic pop
#endif
 
 
static int
mg_vprintf(struct mg_connection *conn, const char *fmt, va_list ap)
{
    char mem[MG_BUF_LEN];
    char *buf = NULL;
    int len;
 
    if ((len = alloc_vprintf(&buf, mem, sizeof(mem), fmt, ap)) > 0) {
        len = mg_write(conn, buf, (size_t)len);
    }
    if (buf != mem) {
        mg_free(buf);
    }
 
    return len;
}
 
 
CIVETWEB_API int
mg_printf(struct mg_connection *conn, const char *fmt, ...)
{
    va_list ap;
    int result;
 
    va_start(ap, fmt);
    result = mg_vprintf(conn, fmt, ap);
    va_end(ap);
 
    return result;
}
 
 
CIVETWEB_API int
mg_url_decode(const char *src,
              int src_len,
              char *dst,
              int dst_len,
              int is_form_url_encoded)
{
    int i, j, a, b;
#define HEXTOI(x) (isdigit(x) ? (x - '0') : (x - 'W'))
 
    for (i = j = 0; (i < src_len) && (j < (dst_len - 1)); i++, j++) {
        if ((i < src_len - 2) && (src[i] == '%')
            && isxdigit((unsigned char)src[i + 1])
            && isxdigit((unsigned char)src[i + 2])) {
            a = tolower((unsigned char)src[i + 1]);
            b = tolower((unsigned char)src[i + 2]);
            dst[j] = (char)((HEXTOI(a) << 4) | HEXTOI(b));
            i += 2;
        } else if (is_form_url_encoded && (src[i] == '+')) {
            dst[j] = ' ';
        } else {
            dst[j] = src[i];
        }
    }
 
    dst[j] = '\0'; /* Null-terminate the destination */
 
    return (i >= src_len) ? j : -1;
}
 
 
/* form url decoding of an entire string */
static void
url_decode_in_place(char *buf)
{
    int len = (int)strlen(buf);
    (void)mg_url_decode(buf, len, buf, len + 1, 1);
}
 
 
CIVETWEB_API int
mg_get_var(const char *data,
           size_t data_len,
           const char *name,
           char *dst,
           size_t dst_len)
{
    return mg_get_var2(data, data_len, name, dst, dst_len, 0);
}
 
 
CIVETWEB_API int
mg_get_var2(const char *data,
            size_t data_len,
            const char *name,
            char *dst,
            size_t dst_len,
            size_t occurrence)
{
    const char *p, *e, *s;
    size_t name_len;
    int len;
 
    if ((dst == NULL) || (dst_len == 0)) {
        len = -2;
    } else if ((data == NULL) || (name == NULL) || (data_len == 0)) {
        len = -1;
        dst[0] = '\0';
    } else {
        name_len = strlen(name);
        e = data + data_len;
        len = -1;
        dst[0] = '\0';
 
        /* data is "var1=val1&var2=val2...". Find variable first */
        for (p = data; p + name_len < e; p++) {
            if (((p == data) || (p[-1] == '&')) && (p[name_len] == '=')
                && !mg_strncasecmp(name, p, name_len) && 0 == occurrence--) {
                /* Point p to variable value */
                p += name_len + 1;
 
                /* Point s to the end of the value */
                s = (const char *)memchr(p, '&', (size_t)(e - p));
                if (s == NULL) {
                    s = e;
                }
                DEBUG_ASSERT(s >= p);
                if (s < p) {
                    return -3;
                }
 
                /* Decode variable into destination buffer */
                len = mg_url_decode(p, (int)(s - p), dst, (int)dst_len, 1);
 
                /* Redirect error code from -1 to -2 (destination buffer too
                 * small). */
                if (len == -1) {
                    len = -2;
                }
                break;
            }
        }
    }
 
    return len;
}
 
 
/* split a string "key1=val1&key2=val2" into key/value pairs */
CIVETWEB_API int
mg_split_form_urlencoded(char *data,
                         struct mg_header *form_fields,
                         unsigned num_form_fields)
{
    char *b;
    int i;
    int num = 0;
 
    if (data == NULL) {
        /* parameter error */
        return -1;
    }
 
    if ((form_fields == NULL) && (num_form_fields == 0)) {
        /* determine the number of expected fields */
        if (data[0] == 0) {
            return 0;
        }
        /* count number of & to return the number of key-value-pairs */
        num = 1;
        while (*data) {
            if (*data == '&') {
                num++;
            }
            data++;
        }
        return num;
    }
 
    if ((form_fields == NULL) || ((int)num_form_fields <= 0)) {
        /* parameter error */
        return -1;
    }
 
    for (i = 0; i < (int)num_form_fields; i++) {
        /* extract key-value pairs from input data */
        while ((*data == ' ') || (*data == '\t')) {
            /* skip initial spaces */
            data++;
        }
        if (*data == 0) {
            /* end of string reached */
            break;
        }
        form_fields[num].name = data;
 
        /* find & or = */
        b = data;
        while ((*b != 0) && (*b != '&') && (*b != '=')) {
            b++;
        }
 
        if (*b == 0) {
            /* last key without value */
            form_fields[num].value = NULL;
        } else if (*b == '&') {
            /* mid key without value */
            form_fields[num].value = NULL;
        } else {
            /* terminate string */
            *b = 0;
            /* value starts after '=' */
            data = b + 1;
            form_fields[num].value = data;
        }
 
        /* new field is stored */
        num++;
 
        /* find a next key */
        b = strchr(data, '&');
        if (b == 0) {
            /* no more data */
            break;
        } else {
            /* terminate value of last field at '&' */
            *b = 0;
            /* next key-value-pairs starts after '&' */
            data = b + 1;
        }
    }
 
    /* Decode all values */
    for (i = 0; i < num; i++) {
        if (form_fields[i].name) {
            url_decode_in_place((char *)form_fields[i].name);
        }
        if (form_fields[i].value) {
            url_decode_in_place((char *)form_fields[i].value);
        }
    }
 
    /* return number of fields found */
    return num;
}
 
 
/* HCP24: some changes to compare whole var_name */
CIVETWEB_API int
mg_get_cookie(const char *cookie_header,
              const char *var_name,
              char *dst,
              size_t dst_size)
{
    const char *s, *p, *end;
    int name_len, len = -1;
 
    if ((dst == NULL) || (dst_size == 0)) {
        return -2;
    }
 
    dst[0] = '\0';
    if ((var_name == NULL) || ((s = cookie_header) == NULL)) {
        return -1;
    }
 
    name_len = (int)strlen(var_name);
    end = s + strlen(s);
    for (; (s = mg_strcasestr(s, var_name)) != NULL; s += name_len) {
        if (s[name_len] == '=') {
            /* HCP24: now check is it a substring or a full cookie name */
            if ((s == cookie_header) || (s[-1] == ' ')) {
                s += name_len + 1;
                if ((p = strchr(s, ' ')) == NULL) {
                    p = end;
                }
                if (p[-1] == ';') {
                    p--;
                }
                if ((*s == '"') && (p[-1] == '"') && (p > s + 1)) {
                    s++;
                    p--;
                }
                if ((size_t)(p - s) < dst_size) {
                    len = (int)(p - s);
                    mg_strlcpy(dst, s, (size_t)len + 1);
                } else {
                    len = -3;
                }
                break;
            }
        }
    }
    return len;
}
 
 
CIVETWEB_API int
mg_base64_encode(const unsigned char *src,
                 size_t src_len,
                 char *dst,
                 size_t *dst_len)
{
    static const char *b64 =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    size_t i, j;
    int a, b, c;
 
    if (dst_len != NULL) {
        /* Expected length including 0 termination: */
        /* IN 1 -> OUT 5, IN 2 -> OUT 5, IN 3 -> OUT 5, IN 4 -> OUT 9,
         * IN 5 -> OUT 9, IN 6 -> OUT 9, IN 7 -> OUT 13, etc. */
        size_t expected_len = ((src_len + 2) / 3) * 4 + 1;
        if (*dst_len < expected_len) {
            if (*dst_len > 0) {
                dst[0] = '\0';
            }
            *dst_len = expected_len;
            return 0;
        }
    }
 
    for (i = j = 0; i < src_len; i += 3) {
        a = src[i];
        b = ((i + 1) >= src_len) ? 0 : src[i + 1];
        c = ((i + 2) >= src_len) ? 0 : src[i + 2];
 
        dst[j++] = b64[a >> 2];
        dst[j++] = b64[((a & 3) << 4) | (b >> 4)];
        if (i + 1 < src_len) {
            dst[j++] = b64[(b & 15) << 2 | (c >> 6)];
        }
        if (i + 2 < src_len) {
            dst[j++] = b64[c & 63];
        }
    }
    while (j % 4 != 0) {
        dst[j++] = '=';
    }
    dst[j++] = '\0';
 
    if (dst_len != NULL) {
        *dst_len = (size_t)j;
    }
 
    /* Return -1 for "OK" */
    return -1;
}
 
 
static unsigned char
b64reverse(char letter)
{
    if ((letter >= 'A') && (letter <= 'Z')) {
        return (unsigned char)(letter - 'A');
    }
    if ((letter >= 'a') && (letter <= 'z')) {
        return (unsigned char)(letter - 'a' + 26);
    }
    if ((letter >= '0') && (letter <= '9')) {
        return (unsigned char)(letter - '0' + 52);
    }
    if (letter == '+') {
        return 62;
    }
    if (letter == '/') {
        return 63;
    }
    if (letter == '=') {
        return 255; /* normal end */
    }
    return 254; /* error */
}
 
 
CIVETWEB_API int
mg_base64_decode(const char *src,
                 size_t src_len,
                 unsigned char *dst,
                 size_t *dst_len)
{
    size_t i;
    unsigned char a, b, c, d;
    size_t dst_len_limit = (size_t)-1;
    size_t dst_len_used = 0;
 
    if (dst_len != NULL) {
        dst_len_limit = *dst_len;
        *dst_len = 0;
    }
 
    for (i = 0; i < src_len; i += 4) {
        /* Read 4 characters from BASE64 string */
        a = b64reverse(src[i]);
        if (a >= 254) {
            return (int)i;
        }
 
        b = b64reverse(((i + 1) >= src_len) ? 0 : src[i + 1]);
        if (b >= 254) {
            return (int)i + 1;
        }
 
        c = b64reverse(((i + 2) >= src_len) ? 0 : src[i + 2]);
        if (c == 254) {
            return (int)i + 2;
        }
 
        d = b64reverse(((i + 3) >= src_len) ? 0 : src[i + 3]);
        if (d == 254) {
            return (int)i + 3;
        }
 
        /* Add first (of 3) decoded character */
        if (dst_len_used < dst_len_limit) {
            dst[dst_len_used] = (unsigned char)((unsigned char)(a << 2)
                                                + (unsigned char)(b >> 4));
        }
        dst_len_used++;
 
        if (c != 255) {
            if (dst_len_used < dst_len_limit) {
 
                dst[dst_len_used] = (unsigned char)((unsigned char)(b << 4)
                                                    + (unsigned char)(c >> 2));
            }
            dst_len_used++;
            if (d != 255) {
                if (dst_len_used < dst_len_limit) {
                    dst[dst_len_used] =
                        (unsigned char)((unsigned char)(c << 6) + d);
                }
                dst_len_used++;
            }
        }
    }
 
    /* Add terminating zero */
    if (dst_len_used < dst_len_limit) {
        dst[dst_len_used] = '\0';
    }
    dst_len_used++;
    if (dst_len != NULL) {
        *dst_len = dst_len_used;
    }
 
    if (dst_len_used > dst_len_limit) {
        /* Out of memory */
        return 0;
    }
 
    /* Return -1 for "OK" */
    return -1;
}
 
 
static int
is_put_or_delete_method(const struct mg_connection *conn)
{
    if (conn) {
        const char *s = conn->request_info.request_method;
        if (s != NULL) {
            /* PUT, DELETE, MKCOL, PATCH, LOCK, UNLOCK, PROPPATCH, MOVE, COPY */
            return (!strcmp(s, "PUT") || !strcmp(s, "DELETE")
                    || !strcmp(s, "MKCOL") || !strcmp(s, "PATCH")
                    || !strcmp(s, "LOCK") || !strcmp(s, "UNLOCK")
                    || !strcmp(s, "PROPPATCH") || !strcmp(s, "MOVE")
                    || !strcmp(s, "COPY"));
        }
    }
    return 0;
}
 
 
static int
is_civetweb_webdav_method(const struct mg_connection *conn)
{
    /* Note: Here we only have to identify the WebDav methods that need special
     * handling in the CivetWeb code - not all methods used in WebDav. In
     * particular, methods used on directories (when using Windows Explorer as
     * WebDav client).
     */
    if (conn) {
        const char *s = conn->request_info.request_method;
        if (s != NULL) {
            /* These are the civetweb builtin DAV methods */
            return (!strcmp(s, "PROPFIND") || !strcmp(s, "PROPPATCH")
                    || !strcmp(s, "LOCK") || !strcmp(s, "UNLOCK")
                    || !strcmp(s, "MOVE") || !strcmp(s, "COPY"));
        }
    }
    return 0;
}
 
 
#if !defined(NO_FILES)
static int
extention_matches_script(
    struct mg_connection *conn, /* in: request (must be valid) */
    const char *filename        /* in: filename  (must be valid) */
)
{
#if !defined(NO_CGI)
    int cgi_config_idx, inc, max;
#endif
 
#if defined(USE_LUA)
    if (match_prefix_strlen(conn->dom_ctx->config[LUA_SCRIPT_EXTENSIONS],
                            filename)
        > 0) {
        return 1;
    }
#endif
#if defined(USE_DUKTAPE)
    if (match_prefix_strlen(conn->dom_ctx->config[DUKTAPE_SCRIPT_EXTENSIONS],
                            filename)
        > 0) {
        return 1;
    }
#endif
#if !defined(NO_CGI)
    inc = CGI2_EXTENSIONS - CGI_EXTENSIONS;
    max = PUT_DELETE_PASSWORDS_FILE - CGI_EXTENSIONS;
    for (cgi_config_idx = 0; cgi_config_idx < max; cgi_config_idx += inc) {
        if ((conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx] != NULL)
            && (match_prefix_strlen(
                    conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx],
                    filename)
                > 0)) {
            return 1;
        }
    }
#endif
    /* filename and conn could be unused, if all preocessor conditions
     * are false (no script language supported). */
    (void)filename;
    (void)conn;
 
    return 0;
}
 
 
static int
extention_matches_template_text(
    struct mg_connection *conn, /* in: request (must be valid) */
    const char *filename        /* in: filename  (must be valid) */
)
{
#if defined(USE_LUA)
    if (match_prefix_strlen(conn->dom_ctx->config[LUA_SERVER_PAGE_EXTENSIONS],
                            filename)
        > 0) {
        return 1;
    }
#endif
    if (match_prefix_strlen(conn->dom_ctx->config[SSI_EXTENSIONS], filename)
        > 0) {
        return 1;
    }
    return 0;
}
 
 
/* For given directory path, substitute it to valid index file.
 * Return 1 if index file has been found, 0 if not found.
 * If the file is found, it's stats is returned in stp. */
static int
substitute_index_file(struct mg_connection *conn,
                      char *path,
                      size_t path_len,
                      struct mg_file_stat *filestat)
{
    const char *list = conn->dom_ctx->config[INDEX_FILES];
    struct vec filename_vec;
    size_t n = strlen(path);
    int found = 0;
 
    /* The 'path' given to us points to the directory. Remove all trailing
     * directory separator characters from the end of the path, and
     * then append single directory separator character. */
    while ((n > 0) && (path[n - 1] == '/')) {
        n--;
    }
    path[n] = '/';
 
    /* Traverse index files list. For each entry, append it to the given
     * path and see if the file exists. If it exists, break the loop */
    while ((list = next_option(list, &filename_vec, NULL)) != NULL) {
        /* Ignore too long entries that may overflow path buffer */
        if ((filename_vec.len + 1) > (path_len - (n + 1))) {
            continue;
        }
 
        /* Prepare full path to the index file */
        mg_strlcpy(path + n + 1, filename_vec.ptr, filename_vec.len + 1);
 
        /* Does it exist? */
        if (mg_stat(conn, path, filestat)) {
            /* Yes it does, break the loop */
            found = 1;
            break;
        }
    }
 
    /* If no index file exists, restore directory path */
    if (!found) {
        path[n] = '\0';
    }
 
    return found;
}
#endif
 
 
static void
interpret_uri(struct mg_connection *conn, /* in/out: request (must be valid) */
              char *filename,             /* out: filename */
              size_t filename_buf_len,    /* in: size of filename buffer */
              struct mg_file_stat *filestat, /* out: file status structure */
              int *is_found,                 /* out: file found (directly) */
              int *is_script_resource,       /* out: handled by a script? */
              int *is_websocket_request,     /* out: websocket connection? */
              int *is_put_or_delete_request, /* out: put/delete a file? */
              int *is_webdav_request,        /* out: webdav request? */
              int *is_template_text          /* out: SSI file or LSP file? */
)
{
    char const *accept_encoding;
 
#if !defined(NO_FILES)
    const char *uri = conn->request_info.local_uri;
    const char *root = conn->dom_ctx->config[DOCUMENT_ROOT];
    const char *rewrite;
    struct vec a, b;
    ptrdiff_t match_len;
    char gz_path[UTF8_PATH_MAX];
    int truncated;
#if !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE)
    char *tmp_str;
    size_t tmp_str_len, sep_pos;
    int allow_substitute_script_subresources;
#endif
#else
    (void)filename_buf_len; /* unused if NO_FILES is defined */
#endif
 
    /* Step 1: Set all initially unknown outputs to zero */
    memset(filestat, 0, sizeof(*filestat));
    *filename = 0;
    *is_found = 0;
    *is_script_resource = 0;
    *is_template_text = 0;
 
    /* Step 2: Classify the request method */
    /* Step 2a: Check if the request attempts to modify the file system */
    *is_put_or_delete_request = is_put_or_delete_method(conn);
    /* Step 2b: Check if the request uses WebDav method that requires special
     * handling */
    *is_webdav_request = is_civetweb_webdav_method(conn);
 
    /* Step 3: Check if it is a websocket request, and modify the document
     * root if required */
#if defined(USE_WEBSOCKET)
    *is_websocket_request = (conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET);
#if !defined(NO_FILES)
    if ((*is_websocket_request) && conn->dom_ctx->config[WEBSOCKET_ROOT]) {
        root = conn->dom_ctx->config[WEBSOCKET_ROOT];
    }
#endif /* !NO_FILES */
#else  /* USE_WEBSOCKET */
    *is_websocket_request = 0;
#endif /* USE_WEBSOCKET */
 
    /* Step 4: Check if gzip encoded response is allowed */
    conn->accept_gzip = 0;
    if ((accept_encoding = mg_get_header(conn, "Accept-Encoding")) != NULL) {
        if (strstr(accept_encoding, "gzip") != NULL) {
            conn->accept_gzip = 1;
        }
    }
 
#if !defined(NO_FILES)
    /* Step 5: If there is no root directory, don't look for files. */
    /* Note that root == NULL is a regular use case here. This occurs,
     * if all requests are handled by callbacks, so the WEBSOCKET_ROOT
     * config is not required. */
    if (root == NULL) {
        /* all file related outputs have already been set to 0, just return
         */
        return;
    }
 
    /* Step 6: Determine the local file path from the root path and the
     * request uri. */
    /* Using filename_buf_len - 1 because memmove() for PATH_INFO may shift
     * part of the path one byte on the right. */
    truncated = 0;
    mg_snprintf(
        conn, &truncated, filename, filename_buf_len - 1, "%s%s", root, uri);
 
    if (truncated) {
        goto interpret_cleanup;
    }
 
    /* Step 7: URI rewriting */
    rewrite = conn->dom_ctx->config[URL_REWRITE_PATTERN];
    while ((rewrite = next_option(rewrite, &a, &b)) != NULL) {
        if ((match_len = match_prefix(a.ptr, a.len, uri)) > 0) {
            mg_snprintf(conn,
                        &truncated,
                        filename,
                        filename_buf_len - 1,
                        "%.*s%s",
                        (int)b.len,
                        b.ptr,
                        uri + match_len);
            break;
        }
    }
 
    if (truncated) {
        goto interpret_cleanup;
    }
 
    /* Step 8: Check if the file exists at the server */
    /* Local file path and name, corresponding to requested URI
     * is now stored in "filename" variable. */
    if (mg_stat(conn, filename, filestat)) {
        int uri_len = (int)strlen(uri);
        int is_uri_end_slash = (uri_len > 0) && (uri[uri_len - 1] == '/');
 
        /* 8.1: File exists. */
        *is_found = 1;
 
        /* 8.2: Check if it is a script type. */
        if (extention_matches_script(conn, filename)) {
            /* The request addresses a CGI resource, Lua script or
             * server-side javascript.
             * The URI corresponds to the script itself (like
             * /path/script.cgi), and there is no additional resource
             * path (like /path/script.cgi/something).
             * Requests that modify (replace or delete) a resource, like
             * PUT and DELETE requests, should replace/delete the script
             * file.
             * Requests that read or write from/to a resource, like GET and
             * POST requests, should call the script and return the
             * generated response. */
            *is_script_resource = (!*is_put_or_delete_request);
        }
 
        /* 8.3: Check for SSI and LSP files */
        if (extention_matches_template_text(conn, filename)) {
            /* Same as above, but for *.lsp and *.shtml files. */
            /* A "template text" is a file delivered directly to the client,
             * but with some text tags replaced by dynamic content.
             * E.g. a Server Side Include (SSI) or Lua Page/Lua Server Page
             * (LP, LSP) file. */
            *is_template_text = (!*is_put_or_delete_request);
        }
 
        /* 8.4: If the request target is a directory, there could be
         * a substitute file (index.html, index.cgi, ...). */
        /* But do not substitute a directory for a WebDav request */
        if (filestat->is_directory && is_uri_end_slash
            && (!*is_webdav_request)) {
            /* Use a local copy here, since substitute_index_file will
             * change the content of the file status */
            struct mg_file_stat tmp_filestat;
            memset(&tmp_filestat, 0, sizeof(tmp_filestat));
 
            if (substitute_index_file(
                    conn, filename, filename_buf_len, &tmp_filestat)) {
 
                /* Substitute file found. Copy stat to the output, then
                 * check if the file is a script file */
                *filestat = tmp_filestat;
 
                if (extention_matches_script(conn, filename)) {
                    /* Substitute file is a script file */
                    *is_script_resource = 1;
                } else if (extention_matches_template_text(conn, filename)) {
                    /* Substitute file is a LSP or SSI file */
                    *is_template_text = 1;
                } else {
                    /* Substitute file is a regular file */
                    *is_script_resource = 0;
                    *is_found = (mg_stat(conn, filename, filestat) ? 1 : 0);
                }
            }
            /* If there is no substitute file, the server could return
             * a directory listing in a later step */
        }
        return;
    }
 
    /* Step 9: Check for zipped files: */
    /* If we can't find the actual file, look for the file
     * with the same name but a .gz extension. If we find it,
     * use that and set the gzipped flag in the file struct
     * to indicate that the response need to have the content-
     * encoding: gzip header.
     * We can only do this if the browser declares support. */
    if (conn->accept_gzip) {
        mg_snprintf(
            conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", filename);
 
        if (truncated) {
            goto interpret_cleanup;
        }
 
        if (mg_stat(conn, gz_path, filestat)) {
            if (filestat) {
                filestat->is_gzipped = 1;
                *is_found = 1;
            }
            /* Currently gz files can not be scripts. */
            return;
        }
    }
 
#if !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE)
    /* Step 10: Script resources may handle sub-resources */
    /* Support PATH_INFO for CGI scripts. */
    tmp_str_len = strlen(filename);
    tmp_str =
        (char *)mg_malloc_ctx(tmp_str_len + UTF8_PATH_MAX + 1, conn->phys_ctx);
    if (!tmp_str) {
        /* Out of memory */
        goto interpret_cleanup;
    }
    memcpy(tmp_str, filename, tmp_str_len + 1);
 
    /* Check config, if index scripts may have sub-resources */
    allow_substitute_script_subresources =
        !mg_strcasecmp(conn->dom_ctx->config[ALLOW_INDEX_SCRIPT_SUB_RES],
                       "yes");
    if (*is_webdav_request) {
        /* TO BE DEFINED: Should scripts handle special WebDAV methods lile
         * PROPFIND for their subresources? */
        /* allow_substitute_script_subresources = 0; */
    }
 
    sep_pos = tmp_str_len;
    while (sep_pos > 0) {
        sep_pos--;
        if (tmp_str[sep_pos] == '/') {
            int is_script = 0, does_exist = 0;
 
            tmp_str[sep_pos] = 0;
            if (tmp_str[0]) {
                is_script = extention_matches_script(conn, tmp_str);
                does_exist = mg_stat(conn, tmp_str, filestat);
            }
 
            if (does_exist && is_script) {
                filename[sep_pos] = 0;
                memmove(filename + sep_pos + 2,
                        filename + sep_pos + 1,
                        strlen(filename + sep_pos + 1) + 1);
                conn->path_info = filename + sep_pos + 1;
                filename[sep_pos + 1] = '/';
                *is_script_resource = 1;
                *is_found = 1;
                break;
            }
 
            if (allow_substitute_script_subresources) {
                if (substitute_index_file(
                        conn, tmp_str, tmp_str_len + UTF8_PATH_MAX, filestat)) {
 
                    /* some intermediate directory has an index file */
                    if (extention_matches_script(conn, tmp_str)) {
 
                        size_t script_name_len = strlen(tmp_str);
 
                        /* subres_name read before this memory locatio will be
                        overwritten */
                        char *subres_name = filename + sep_pos;
                        size_t subres_name_len = strlen(subres_name);
 
                        DEBUG_TRACE("Substitute script %s serving path %s",
                                    tmp_str,
                                    filename);
 
                        /* this index file is a script */
                        if ((script_name_len + subres_name_len + 2)
                            >= filename_buf_len) {
                            mg_free(tmp_str);
                            goto interpret_cleanup;
                        }
 
                        conn->path_info =
                            filename + script_name_len + 1; /* new target */
                        memmove(conn->path_info, subres_name, subres_name_len);
                        conn->path_info[subres_name_len] = 0;
                        memcpy(filename, tmp_str, script_name_len + 1);
 
                        *is_script_resource = 1;
                        *is_found = 1;
                        break;
 
                    } else {
 
                        DEBUG_TRACE("Substitute file %s serving path %s",
                                    tmp_str,
                                    filename);
 
                        /* non-script files will not have sub-resources */
                        filename[sep_pos] = 0;
                        conn->path_info = 0;
                        *is_script_resource = 0;
                        *is_found = 0;
                        break;
                    }
                }
            }
 
            tmp_str[sep_pos] = '/';
        }
    }
 
    mg_free(tmp_str);
 
#endif /* !defined(NO_CGI) || defined(USE_LUA) || defined(USE_DUKTAPE) */
#endif /* !defined(NO_FILES) */
    return;
 
#if !defined(NO_FILES)
/* Reset all outputs */
interpret_cleanup:
    memset(filestat, 0, sizeof(*filestat));
    *filename = 0;
    *is_found = 0;
    *is_script_resource = 0;
    *is_websocket_request = 0;
    *is_put_or_delete_request = 0;
#endif /* !defined(NO_FILES) */
}
 
 
/* Check whether full request is buffered. Return:
 * -1  if request or response is malformed
 *  0  if request or response is not yet fully buffered
 * >0  actual request length, including last \r\n\r\n */
static int
get_http_header_len(const char *buf, int buflen)
{
    int i;
    for (i = 0; i < buflen; i++) {
        /* Do an unsigned comparison in some conditions below */
        const unsigned char c = (unsigned char)buf[i];
 
        if ((c < 128) && ((char)c != '\r') && ((char)c != '\n')
            && !isprint(c)) {
            /* abort scan as soon as one malformed character is found */
            return -1;
        }
 
        if (i < buflen - 1) {
            if ((buf[i] == '\n') && (buf[i + 1] == '\n')) {
                /* Two newline, no carriage return - not standard compliant,
                 * but it should be accepted */
                return i + 2;
            }
        }
 
        if (i < buflen - 3) {
            if ((buf[i] == '\r') && (buf[i + 1] == '\n') && (buf[i + 2] == '\r')
                && (buf[i + 3] == '\n')) {
                /* Two \r\n - standard compliant */
                return i + 4;
            }
        }
    }
 
    return 0;
}
 
 
#if !defined(NO_CACHING)
/* Convert month to the month number. Return -1 on error, or month number */
static int
get_month_index(const char *s)
{
    size_t i;
 
    for (i = 0; i < ARRAY_SIZE(month_names); i++) {
        if (!strcmp(s, month_names[i])) {
            return (int)i;
        }
    }
 
    return -1;
}
 
 
/* Parse UTC date-time string, and return the corresponding time_t value. */
static time_t
parse_date_string(const char *datetime)
{
    char month_str[32] = {0};
    int second, minute, hour, day, month, year;
    time_t result = (time_t)0;
    struct tm tm;
 
    if ((sscanf(datetime,
                "%d/%3s/%d %d:%d:%d",
                &day,
                month_str,
                &year,
                &hour,
                &minute,
                &second)
         == 6)
        || (sscanf(datetime,
                   "%d %3s %d %d:%d:%d",
                   &day,
                   month_str,
                   &year,
                   &hour,
                   &minute,
                   &second)
            == 6)
        || (sscanf(datetime,
                   "%*3s, %d %3s %d %d:%d:%d",
                   &day,
                   month_str,
                   &year,
                   &hour,
                   &minute,
                   &second)
            == 6)
        || (sscanf(datetime,
                   "%d-%3s-%d %d:%d:%d",
                   &day,
                   month_str,
                   &year,
                   &hour,
                   &minute,
                   &second)
            == 6)) {
        month = get_month_index(month_str);
        if ((month >= 0) && (year >= 1970)) {
            memset(&tm, 0, sizeof(tm));
            tm.tm_year = year - 1900;
            tm.tm_mon = month;
            tm.tm_mday = day;
            tm.tm_hour = hour;
            tm.tm_min = minute;
            tm.tm_sec = second;
            result = timegm(&tm);
        }
    }
 
    return result;
}
#endif /* !NO_CACHING */
 
 
/* Pre-process URIs according to RFC + protect against directory disclosure
 * attacks by removing '..', excessive '/' and '\' characters */
static void
remove_dot_segments(char *inout)
{
    /* Windows backend protection
     * (https://tools.ietf.org/html/rfc3986#section-7.3): Replace backslash
     * in URI by slash */
    char *out_end = inout;
    char *in = inout;
 
    if (!in) {
        /* Param error. */
        return;
    }
 
    while (*in) {
        if (*in == '\\') {
            *in = '/';
        }
        in++;
    }
 
    /* Algorithm "remove_dot_segments" from
     * https://tools.ietf.org/html/rfc3986#section-5.2.4 */
    /* Step 1:
     * The input buffer is initialized.
     * The output buffer is initialized to the empty string.
     */
    in = inout;
 
    /* Step 2:
     * While the input buffer is not empty, loop as follows:
     */
    /* Less than out_end of the inout buffer is used as output, so keep
     * condition: out_end <= in */
    while (*in) {
        /* Step 2a:
         * If the input buffer begins with a prefix of "../" or "./",
         * then remove that prefix from the input buffer;
         */
        if (!strncmp(in, "../", 3)) {
            in += 3;
        } else if (!strncmp(in, "./", 2)) {
            in += 2;
        }
        /* otherwise */
        /* Step 2b:
         * if the input buffer begins with a prefix of "/./" or "/.",
         * where "." is a complete path segment, then replace that
         * prefix with "/" in the input buffer;
         */
        else if (!strncmp(in, "/./", 3)) {
            in += 2;
        } else if (!strcmp(in, "/.")) {
            in[1] = 0;
        }
        /* otherwise */
        /* Step 2c:
         * if the input buffer begins with a prefix of "/../" or "/..",
         * where ".." is a complete path segment, then replace that
         * prefix with "/" in the input buffer and remove the last
         * segment and its preceding "/" (if any) from the output
         * buffer;
         */
        else if (!strncmp(in, "/../", 4)) {
            in += 3;
            if (inout != out_end) {
                /* remove last segment */
                do {
                    out_end--;
                } while ((inout != out_end) && (*out_end != '/'));
            }
        } else if (!strcmp(in, "/..")) {
            in[1] = 0;
            if (inout != out_end) {
                /* remove last segment */
                do {
                    out_end--;
                } while ((inout != out_end) && (*out_end != '/'));
            }
        }
        /* otherwise */
        /* Step 2d:
         * if the input buffer consists only of "." or "..", then remove
         * that from the input buffer;
         */
        else if (!strcmp(in, ".") || !strcmp(in, "..")) {
            *in = 0;
        }
        /* otherwise */
        /* Step 2e:
         * move the first path segment in the input buffer to the end of
         * the output buffer, including the initial "/" character (if
         * any) and any subsequent characters up to, but not including,
         * the next "/" character or the end of the input buffer.
         */
        else {
            do {
                *out_end = *in;
                out_end++;
                in++;
            } while ((*in != 0) && (*in != '/'));
        }
    }
 
    /* Step 3:
     * Finally, the output buffer is returned as the result of
     * remove_dot_segments.
     */
    /* Terminate output */
    *out_end = 0;
 
    /* For Windows, the files/folders "x" and "x." (with a dot but without
     * extension) are identical. Replace all "./" by "/" and remove a "." at
     * the end. Also replace all "//" by "/". Repeat until there is no "./"
     * or "//" anymore.
     */
    out_end = in = inout;
    while (*in) {
        if (*in == '.') {
            /* remove . at the end or preceding of / */
            char *in_ahead = in;
            do {
                in_ahead++;
            } while (*in_ahead == '.');
            if (*in_ahead == '/') {
                in = in_ahead;
                if ((out_end != inout) && (out_end[-1] == '/')) {
                    /* remove generated // */
                    out_end--;
                }
            } else if (*in_ahead == 0) {
                in = in_ahead;
            } else {
                do {
                    *out_end++ = '.';
                    in++;
                } while (in != in_ahead);
            }
        } else if (*in == '/') {
            /* replace // by / */
            *out_end++ = '/';
            do {
                in++;
            } while (*in == '/');
        } else {
            *out_end++ = *in;
            in++;
        }
    }
    *out_end = 0;
}
 
 
static const struct {
    const char *extension;
    size_t ext_len;
    const char *mime_type;
} builtin_mime_types[] = {
    /* IANA registered MIME types
     * (http://www.iana.org/assignments/media-types)
     * application types */
    {".bin", 4, "application/octet-stream"},
    {".deb", 4, "application/octet-stream"},
    {".dmg", 4, "application/octet-stream"},
    {".dll", 4, "application/octet-stream"},
    {".doc", 4, "application/msword"},
    {".eps", 4, "application/postscript"},
    {".exe", 4, "application/octet-stream"},
    {".iso", 4, "application/octet-stream"},
    {".js", 3, "application/javascript"},
    {".json", 5, "application/json"},
    {".msi", 4, "application/octet-stream"},
    {".pdf", 4, "application/pdf"},
    {".ps", 3, "application/postscript"},
    {".rtf", 4, "application/rtf"},
    {".xhtml", 6, "application/xhtml+xml"},
    {".xsl", 4, "application/xml"},
    {".xslt", 5, "application/xml"},
 
    /* fonts */
    {".ttf", 4, "application/font-sfnt"},
    {".cff", 4, "application/font-sfnt"},
    {".otf", 4, "application/font-sfnt"},
    {".aat", 4, "application/font-sfnt"},
    {".sil", 4, "application/font-sfnt"},
    {".pfr", 4, "application/font-tdpfr"},
    {".woff", 5, "application/font-woff"},
    {".woff2", 6, "application/font-woff2"},
 
    /* audio */
    {".mp3", 4, "audio/mpeg"},
    {".oga", 4, "audio/ogg"},
    {".ogg", 4, "audio/ogg"},
 
    /* image */
    {".gif", 4, "image/gif"},
    {".ief", 4, "image/ief"},
    {".jpeg", 5, "image/jpeg"},
    {".jpg", 4, "image/jpeg"},
    {".jpm", 4, "image/jpm"},
    {".jpx", 4, "image/jpx"},
    {".png", 4, "image/png"},
    {".svg", 4, "image/svg+xml"},
    {".tif", 4, "image/tiff"},
    {".tiff", 5, "image/tiff"},
 
    /* model */
    {".wrl", 4, "model/vrml"},
 
    /* text */
    {".css", 4, "text/css"},
    {".csv", 4, "text/csv"},
    {".htm", 4, "text/html"},
    {".html", 5, "text/html"},
    {".sgm", 4, "text/sgml"},
    {".shtm", 5, "text/html"},
    {".shtml", 6, "text/html"},
    {".txt", 4, "text/plain"},
    {".xml", 4, "text/xml"},
 
    /* video */
    {".mov", 4, "video/quicktime"},
    {".mp4", 4, "video/mp4"},
    {".mpeg", 5, "video/mpeg"},
    {".mpg", 4, "video/mpeg"},
    {".ogv", 4, "video/ogg"},
    {".qt", 3, "video/quicktime"},
 
    /* not registered types
     * (http://reference.sitepoint.com/html/mime-types-full,
     * http://www.hansenb.pdx.edu/DMKB/dict/tutorials/mime_typ.php, ..) */
    {".arj", 4, "application/x-arj-compressed"},
    {".gz", 3, "application/x-gunzip"},
    {".rar", 4, "application/x-arj-compressed"},
    {".swf", 4, "application/x-shockwave-flash"},
    {".tar", 4, "application/x-tar"},
    {".tgz", 4, "application/x-tar-gz"},
    {".torrent", 8, "application/x-bittorrent"},
    {".ppt", 4, "application/x-mspowerpoint"},
    {".xls", 4, "application/x-msexcel"},
    {".zip", 4, "application/x-zip-compressed"},
    {".aac",
     4,
     "audio/aac"}, /* http://en.wikipedia.org/wiki/Advanced_Audio_Coding */
    {".flac", 5, "audio/flac"},
    {".aif", 4, "audio/x-aif"},
    {".m3u", 4, "audio/x-mpegurl"},
    {".mid", 4, "audio/x-midi"},
    {".ra", 3, "audio/x-pn-realaudio"},
    {".ram", 4, "audio/x-pn-realaudio"},
    {".wav", 4, "audio/x-wav"},
    {".bmp", 4, "image/bmp"},
    {".ico", 4, "image/x-icon"},
    {".pct", 4, "image/x-pct"},
    {".pict", 5, "image/pict"},
    {".rgb", 4, "image/x-rgb"},
    {".webm", 5, "video/webm"}, /* http://en.wikipedia.org/wiki/WebM */
    {".asf", 4, "video/x-ms-asf"},
    {".avi", 4, "video/x-msvideo"},
    {".m4v", 4, "video/x-m4v"},
    {NULL, 0, NULL}};
 
 
CIVETWEB_API const char *
mg_get_builtin_mime_type(const char *path)
{
    const char *ext;
    size_t i, path_len;
 
    path_len = strlen(path);
 
    for (i = 0; builtin_mime_types[i].extension != NULL; i++) {
        ext = path + (path_len - builtin_mime_types[i].ext_len);
        if ((path_len > builtin_mime_types[i].ext_len)
            && (mg_strcasecmp(ext, builtin_mime_types[i].extension) == 0)) {
            return builtin_mime_types[i].mime_type;
        }
    }
 
    return "text/plain";
}
 
 
/* Look at the "path" extension and figure what mime type it has.
 * Store mime type in the vector. */
static void
get_mime_type(struct mg_connection *conn, const char *path, struct vec *vec)
{
    struct vec ext_vec, mime_vec;
    const char *list, *ext;
    size_t path_len;
 
    path_len = strlen(path);
 
    if ((conn == NULL) || (vec == NULL)) {
        if (vec != NULL) {
            memset(vec, '\0', sizeof(struct vec));
        }
        return;
    }
 
    /* Scan user-defined mime types first, in case user wants to
     * override default mime types. */
    list = conn->dom_ctx->config[EXTRA_MIME_TYPES];
    while ((list = next_option(list, &ext_vec, &mime_vec)) != NULL) {
        /* ext now points to the path suffix */
        ext = path + path_len - ext_vec.len;
        if (mg_strncasecmp(ext, ext_vec.ptr, ext_vec.len) == 0) {
            *vec = mime_vec;
            return;
        }
    }
 
    vec->ptr = mg_get_builtin_mime_type(path);
    vec->len = strlen(vec->ptr);
}
 
 
/* Stringify binary data. Output buffer must be twice as big as input,
 * because each byte takes 2 bytes in string representation */
static void
bin2str(char *to, const unsigned char *p, size_t len)
{
    static const char *hex = "0123456789abcdef";
 
    for (; len--; p++) {
        *to++ = hex[p[0] >> 4];
        *to++ = hex[p[0] & 0x0f];
    }
    *to = '\0';
}
 
 
/* Return stringified MD5 hash for list of strings. Buffer must be 33 bytes.
 */
CIVETWEB_API char *
mg_md5(char buf[33], ...)
{
    md5_byte_t hash[16];
    const char *p;
    va_list ap;
    md5_state_t ctx;
 
    md5_init(&ctx);
 
    va_start(ap, buf);
    while ((p = va_arg(ap, const char *)) != NULL) {
        md5_append(&ctx, (const md5_byte_t *)p, strlen(p));
    }
    va_end(ap);
 
    md5_finish(&ctx, hash);
    bin2str(buf, hash, sizeof(hash));
    return buf;
}
 
 
/* Check the user's password, return 1 if OK */
static int
check_password_digest(const char *method,
                      const char *ha1,
                      const char *uri,
                      const char *nonce,
                      const char *nc,
                      const char *cnonce,
                      const char *qop,
                      const char *response)
{
    char ha2[32 + 1], expected_response[32 + 1];
 
    /* Some of the parameters may be NULL */
    if ((method == NULL) || (nonce == NULL) || (nc == NULL) || (cnonce == NULL)
        || (qop == NULL) || (response == NULL)) {
        return 0;
    }
 
    /* NOTE(lsm): due to a bug in MSIE, we do not compare the URI */
    if (strlen(response) != 32) {
        return 0;
    }
 
    mg_md5(ha2, method, ":", uri, NULL);
    mg_md5(expected_response,
           ha1,
           ":",
           nonce,
           ":",
           nc,
           ":",
           cnonce,
           ":",
           qop,
           ":",
           ha2,
           NULL);
 
    return mg_strcasecmp(response, expected_response) == 0;
}
 
 
#if !defined(NO_FILESYSTEMS)
/* Use the global passwords file, if specified by auth_gpass option,
 * or search for .htpasswd in the requested directory. */
static void
open_auth_file(struct mg_connection *conn,
               const char *path,
               struct mg_file *filep)
{
    if ((conn != NULL) && (conn->dom_ctx != NULL)) {
        char name[UTF8_PATH_MAX];
        const char *p, *e,
            *gpass = conn->dom_ctx->config[GLOBAL_PASSWORDS_FILE];
        int truncated;
 
        if (gpass != NULL) {
            /* Use global passwords file */
            if (!mg_fopen(conn, gpass, MG_FOPEN_MODE_READ, filep)) {
#if defined(DEBUG)
                /* Use mg_cry_internal here, since gpass has been
                 * configured. */
                mg_cry_internal(conn, "fopen(%s): %s", gpass, strerror(ERRNO));
#endif
            }
            /* Important: using local struct mg_file to test path for
             * is_directory flag. If filep is used, mg_stat() makes it
             * appear as if auth file was opened.
             * TODO(mid): Check if this is still required after rewriting
             * mg_stat */
        } else if (mg_stat(conn, path, &filep->stat)
                   && filep->stat.is_directory) {
            mg_snprintf(conn,
                        &truncated,
                        name,
                        sizeof(name),
                        "%s/%s",
                        path,
                        PASSWORDS_FILE_NAME);
 
            if (truncated || !mg_fopen(conn, name, MG_FOPEN_MODE_READ, filep)) {
#if defined(DEBUG)
                /* Don't use mg_cry_internal here, but only a trace, since
                 * this is a typical case. It will occur for every directory
                 * without a password file. */
                DEBUG_TRACE("fopen(%s): %s", name, strerror(ERRNO));
#endif
            }
        } else {
            /* Try to find .htpasswd in requested directory. */
            for (p = path, e = p + strlen(p) - 1; e > p; e--) {
                if (e[0] == '/') {
                    break;
                }
            }
            mg_snprintf(conn,
                        &truncated,
                        name,
                        sizeof(name),
                        "%.*s/%s",
                        (int)(e - p),
                        p,
                        PASSWORDS_FILE_NAME);
 
            if (truncated || !mg_fopen(conn, name, MG_FOPEN_MODE_READ, filep)) {
#if defined(DEBUG)
                /* Don't use mg_cry_internal here, but only a trace, since
                 * this is a typical case. It will occur for every directory
                 * without a password file. */
                DEBUG_TRACE("fopen(%s): %s", name, strerror(ERRNO));
#endif
            }
        }
    }
}
#endif /* NO_FILESYSTEMS */
 
 
/* Parsed Authorization header */
struct ah {
    char *user;
    int type;             /* 1 = basic, 2 = digest */
    char *plain_password; /* Basic only */
    char *uri, *cnonce, *response, *qop, *nc, *nonce; /* Digest only */
};
 
 
/* Return 1 on success. Always initializes the ah structure. */
static int
parse_auth_header(struct mg_connection *conn,
                  char *buf,
                  size_t buf_size,
                  struct ah *ah)
{
    char *name, *value, *s;
    const char *auth_header;
    uint64_t nonce;
 
    if (!ah || !conn) {
        return 0;
    }
 
    (void)memset(ah, 0, sizeof(*ah));
    auth_header = mg_get_header(conn, "Authorization");
 
    if (auth_header == NULL) {
        /* No Authorization header at all */
        return 0;
    }
    if (0 == mg_strncasecmp(auth_header, "Basic ", 6)) {
        /* Basic Auth (we never asked for this, but some client may send it) */
        char *split;
        const char *userpw_b64 = auth_header + 6;
        size_t userpw_b64_len = strlen(userpw_b64);
        size_t buf_len_r = buf_size;
        if (mg_base64_decode(
                userpw_b64, userpw_b64_len, (unsigned char *)buf, &buf_len_r)
            != -1) {
            return 0; /* decode error */
        }
        split = strchr(buf, ':');
        if (!split) {
            return 0; /* Format error */
        }
 
        /* Separate string at ':' */
        *split = 0;
 
        /* User name is before ':', Password is after ':'  */
        ah->user = buf;
        ah->type = 1;
        ah->plain_password = split + 1;
 
        return 1;
 
    } else if (0 == mg_strncasecmp(auth_header, "Digest ", 7)) {
        /* Digest Auth ... implemented below */
        ah->type = 2;
 
    } else {
        /* Unknown or invalid Auth method */
        return 0;
    }
 
    /* Make modifiable copy of the auth header */
    (void)mg_strlcpy(buf, auth_header + 7, buf_size);
    s = buf;
 
    /* Parse authorization header */
    for (;;) {
        /* Gobble initial spaces */
        while (isspace((unsigned char)*s)) {
            s++;
        }
        name = skip_quoted(&s, "=", " ", 0);
        /* Value is either quote-delimited, or ends at first comma or space.
         */
        if (s[0] == '\"') {
            s++;
            value = skip_quoted(&s, "\"", " ", '\\');
            if (s[0] == ',') {
                s++;
            }
        } else {
            value = skip_quoted(&s, ", ", " ", 0); /* IE uses commas, FF
                                                    * uses spaces */
        }
        if (*name == '\0') {
            break;
        }
 
        if (!strcmp(name, "username")) {
            ah->user = value;
        } else if (!strcmp(name, "cnonce")) {
            ah->cnonce = value;
        } else if (!strcmp(name, "response")) {
            ah->response = value;
        } else if (!strcmp(name, "uri")) {
            ah->uri = value;
        } else if (!strcmp(name, "qop")) {
            ah->qop = value;
        } else if (!strcmp(name, "nc")) {
            ah->nc = value;
        } else if (!strcmp(name, "nonce")) {
            ah->nonce = value;
        }
    }
 
#if !defined(NO_NONCE_CHECK)
    /* Read the nonce from the response. */
    if (ah->nonce == NULL) {
        return 0;
    }
    s = NULL;
    nonce = strtoull(ah->nonce, &s, 10);
    if ((s == NULL) || (*s != 0)) {
        return 0;
    }
 
    /* Convert the nonce from the client to a number. */
    nonce ^= conn->dom_ctx->auth_nonce_mask;
 
    /* The converted number corresponds to the time the nounce has been
     * created. This should not be earlier than the server start. */
    /* Server side nonce check is valuable in all situations but one:
     * if the server restarts frequently, but the client should not see
     * that, so the server should accept nonces from previous starts. */
    /* However, the reasonable default is to not accept a nonce from a
     * previous start, so if anyone changed the access rights between
     * two restarts, a new login is required. */
    if (nonce < (uint64_t)conn->phys_ctx->start_time) {
        /* nonce is from a previous start of the server and no longer valid
         * (replay attack?) */
        return 0;
    }
    /* Check if the nonce is too high, so it has not (yet) been used by the
     * server. */
    if (nonce >= ((uint64_t)conn->phys_ctx->start_time
                  + conn->dom_ctx->nonce_count)) {
        return 0;
    }
#else
    (void)nonce;
#endif
 
    return (ah->user != NULL);
}
 
 
static const char *
mg_fgets(char *buf, size_t size, struct mg_file *filep)
{
    if (!filep) {
        return NULL;
    }
 
    if (filep->access.fp != NULL) {
        return fgets(buf, (int)size, filep->access.fp);
    } else {
        return NULL;
    }
}
 
/* Define the initial recursion depth for procesesing htpasswd files that
 * include other htpasswd
 * (or even the same) files.  It is not difficult to provide a file or files
 * s.t. they force civetweb
 * to infinitely recurse and then crash.
 */
#define INITIAL_DEPTH 9
#if INITIAL_DEPTH <= 0
#error Bad INITIAL_DEPTH for recursion, set to at least 1
#endif
 
#if !defined(NO_FILESYSTEMS)
struct read_auth_file_struct {
    struct mg_connection *conn;
    struct ah ah;
    const char *domain;
    char buf[256 + 256 + 40];
    const char *f_user;
    const char *f_domain;
    const char *f_ha1;
};
 
 
static int
read_auth_file(struct mg_file *filep,
               struct read_auth_file_struct *workdata,
               int depth)
{
    int is_authorized = 0;
    struct mg_file fp;
    size_t l;
 
    if (!filep || !workdata || (0 == depth)) {
        return 0;
    }
 
    /* Loop over passwords file */
    while (mg_fgets(workdata->buf, sizeof(workdata->buf), filep) != NULL) {
        l = strlen(workdata->buf);
        while (l > 0) {
            if (isspace((unsigned char)workdata->buf[l - 1])
                || iscntrl((unsigned char)workdata->buf[l - 1])) {
                l--;
                workdata->buf[l] = 0;
            } else
                break;
        }
        if (l < 1) {
            continue;
        }
 
        workdata->f_user = workdata->buf;
 
        if (workdata->f_user[0] == ':') {
            /* user names may not contain a ':' and may not be empty,
             * so lines starting with ':' may be used for a special purpose
             */
            if (workdata->f_user[1] == '#') {
                /* :# is a comment */
                continue;
            } else if (!strncmp(workdata->f_user + 1, "include=", 8)) {
                if (mg_fopen(workdata->conn,
                             workdata->f_user + 9,
                             MG_FOPEN_MODE_READ,
                             &fp)) {
                    is_authorized = read_auth_file(&fp, workdata, depth - 1);
                    (void)mg_fclose(
                        &fp.access); /* ignore error on read only file */
 
                    /* No need to continue processing files once we have a
                     * match, since nothing will reset it back
                     * to 0.
                     */
                    if (is_authorized) {
                        return is_authorized;
                    }
                } else {
                    mg_cry_internal(workdata->conn,
                                    "%s: cannot open authorization file: %s",
                                    __func__,
                                    workdata->buf);
                }
                continue;
            }
            /* everything is invalid for the moment (might change in the
             * future) */
            mg_cry_internal(workdata->conn,
                            "%s: syntax error in authorization file: %s",
                            __func__,
                            workdata->buf);
            continue;
        }
 
        workdata->f_domain = strchr(workdata->f_user, ':');
        if (workdata->f_domain == NULL) {
            mg_cry_internal(workdata->conn,
                            "%s: syntax error in authorization file: %s",
                            __func__,
                            workdata->buf);
            continue;
        }
        *(char *)(workdata->f_domain) = 0;
        (workdata->f_domain)++;
 
        workdata->f_ha1 = strchr(workdata->f_domain, ':');
        if (workdata->f_ha1 == NULL) {
            mg_cry_internal(workdata->conn,
                            "%s: syntax error in authorization file: %s",
                            __func__,
                            workdata->buf);
            continue;
        }
        *(char *)(workdata->f_ha1) = 0;
        (workdata->f_ha1)++;
 
        if (!strcmp(workdata->ah.user, workdata->f_user)
            && !strcmp(workdata->domain, workdata->f_domain)) {
            switch (workdata->ah.type) {
            case 1: /* Basic */
            {
                char md5[33];
                mg_md5(md5,
                       workdata->f_user,
                       ":",
                       workdata->domain,
                       ":",
                       workdata->ah.plain_password,
                       NULL);
                return 0 == memcmp(workdata->f_ha1, md5, 33);
            }
            case 2: /* Digest */
                return check_password_digest(
                    workdata->conn->request_info.request_method,
                    workdata->f_ha1,
                    workdata->ah.uri,
                    workdata->ah.nonce,
                    workdata->ah.nc,
                    workdata->ah.cnonce,
                    workdata->ah.qop,
                    workdata->ah.response);
            default: /* None/Other/Unknown */
                return 0;
            }
        }
    }
 
    return is_authorized;
}
 
 
/* Authorize against the opened passwords file. Return 1 if authorized. */
static int
authorize(struct mg_connection *conn, struct mg_file *filep, const char *realm)
{
    struct read_auth_file_struct workdata;
    char buf[MG_BUF_LEN];
 
    if (!conn || !conn->dom_ctx) {
        return 0;
    }
 
    memset(&workdata, 0, sizeof(workdata));
    workdata.conn = conn;
 
    if (!parse_auth_header(conn, buf, sizeof(buf), &workdata.ah)) {
        return 0;
    }
 
    /* CGI needs it as REMOTE_USER */
    conn->request_info.remote_user =
        mg_strdup_ctx(workdata.ah.user, conn->phys_ctx);
 
    if (realm) {
        workdata.domain = realm;
    } else {
        workdata.domain = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
    }
 
    return read_auth_file(filep, &workdata, INITIAL_DEPTH);
}
 
 
/* Public function to check http digest authentication header */
CIVETWEB_API int
mg_check_digest_access_authentication(struct mg_connection *conn,
                                      const char *realm,
                                      const char *filename)
{
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    int auth;
 
    if (!conn || !filename) {
        return -1;
    }
    if (!mg_fopen(conn, filename, MG_FOPEN_MODE_READ, &file)) {
        return -2;
    }
 
    auth = authorize(conn, &file, realm);
 
    mg_fclose(&file.access);
 
    return auth;
}
#endif /* NO_FILESYSTEMS */
 
 
/* Return 1 if request is authorised, 0 otherwise. */
static int
check_authorization(struct mg_connection *conn, const char *path)
{
#if !defined(NO_FILESYSTEMS)
    char fname[UTF8_PATH_MAX];
    struct vec uri_vec, filename_vec;
    const char *list;
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    int authorized = 1, truncated;
 
    if (!conn || !conn->dom_ctx) {
        return 0;
    }
 
    list = conn->dom_ctx->config[PROTECT_URI];
    while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL) {
        if (!memcmp(conn->request_info.local_uri, uri_vec.ptr, uri_vec.len)) {
            mg_snprintf(conn,
                        &truncated,
                        fname,
                        sizeof(fname),
                        "%.*s",
                        (int)filename_vec.len,
                        filename_vec.ptr);
 
            if (truncated
                || !mg_fopen(conn, fname, MG_FOPEN_MODE_READ, &file)) {
                mg_cry_internal(conn,
                                "%s: cannot open %s: %s",
                                __func__,
                                fname,
                                strerror(errno));
            }
            break;
        }
    }
 
    if (!is_file_opened(&file.access)) {
        open_auth_file(conn, path, &file);
    }
 
    if (is_file_opened(&file.access)) {
        authorized = authorize(conn, &file, NULL);
        (void)mg_fclose(&file.access); /* ignore error on read only file */
    }
 
    return authorized;
#else
    (void)conn;
    (void)path;
    return 1;
#endif /* NO_FILESYSTEMS */
}
 
 
/* Internal function. Assumes conn is valid */
static void
send_authorization_request(struct mg_connection *conn, const char *realm)
{
    uint64_t nonce = (uint64_t)(conn->phys_ctx->start_time);
    int trunc = 0;
    char buf[128];
 
    if (!realm) {
        realm = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
    }
 
    mg_lock_context(conn->phys_ctx);
    nonce += conn->dom_ctx->nonce_count;
    ++conn->dom_ctx->nonce_count;
    mg_unlock_context(conn->phys_ctx);
 
    nonce ^= conn->dom_ctx->auth_nonce_mask;
    conn->must_close = 1;
 
    /* Create 401 response */
    mg_response_header_start(conn, 401);
    send_no_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn, "Content-Length", "0", -1);
 
    /* Content for "WWW-Authenticate" header */
    mg_snprintf(conn,
                &trunc,
                buf,
                sizeof(buf),
                "Digest qop=\"auth\", realm=\"%s\", "
                "nonce=\"%" UINT64_FMT "\"",
                realm,
                nonce);
 
    if (!trunc) {
        /* !trunc should always be true */
        mg_response_header_add(conn, "WWW-Authenticate", buf, -1);
    }
 
    /* Send all headers */
    mg_response_header_send(conn);
}
 
 
/* Interface function. Parameters are provided by the user, so do
 * at least some basic checks.
 */
CIVETWEB_API int
mg_send_digest_access_authentication_request(struct mg_connection *conn,
                                             const char *realm)
{
    if (conn && conn->dom_ctx) {
        send_authorization_request(conn, realm);
        return 0;
    }
    return -1;
}
 
 
#if !defined(NO_FILES)
static int
is_authorized_for_put(struct mg_connection *conn)
{
    int ret = 0;
 
    if (conn) {
        struct mg_file file = STRUCT_FILE_INITIALIZER;
        const char *passfile = conn->dom_ctx->config[PUT_DELETE_PASSWORDS_FILE];
 
        if (passfile != NULL
            && mg_fopen(conn, passfile, MG_FOPEN_MODE_READ, &file)) {
            ret = authorize(conn, &file, NULL);
            (void)mg_fclose(&file.access); /* ignore error on read only file */
        }
    }
 
    DEBUG_TRACE("file write authorization: %i", ret);
    return ret;
}
#endif
 
 
CIVETWEB_API int
mg_modify_passwords_file_ha1(const char *fname,
                             const char *domain,
                             const char *user,
                             const char *ha1)
{
    int found = 0, i, result = 1;
    char line[512], u[256], d[256], h[256];
    struct stat st = {0};
    FILE *fp = NULL;
    char *temp_file = NULL;
    int temp_file_offs = 0;
 
    /* Regard empty password as no password - remove user record. */
    if ((ha1 != NULL) && (ha1[0] == '\0')) {
        ha1 = NULL;
    }
 
    /* Other arguments must not be empty */
    if ((fname == NULL) || (domain == NULL) || (user == NULL)) {
        return 0;
    }
 
    /* Using the given file format, user name and domain must not contain
     * the ':' character */
    if (strchr(user, ':') != NULL) {
        return 0;
    }
    if (strchr(domain, ':') != NULL) {
        return 0;
    }
 
    /* Do not allow control characters like newline in user name and domain.
     * Do not allow excessively long names either. */
    for (i = 0; ((i < 255) && (user[i] != 0)); i++) {
        if (iscntrl((unsigned char)user[i])) {
            return 0;
        }
    }
    if (user[i]) {
        return 0; /* user name too long */
    }
    for (i = 0; ((i < 255) && (domain[i] != 0)); i++) {
        if (iscntrl((unsigned char)domain[i])) {
            return 0;
        }
    }
    if (domain[i]) {
        return 0; /* domain name too long */
    }
 
    /* The maximum length of the path to the password file is limited */
    if (strlen(fname) >= UTF8_PATH_MAX) {
        return 0;
    }
 
    /* Check if the file exists, and get file size */
    if (0 == stat(fname, &st)) {
        int temp_buf_len;
        if (st.st_size > 10485760) {
            /* Some funster provided a >10 MB text file */
            return 0;
        }
 
        /* Add enough space for one more line */
        temp_buf_len = (int)st.st_size + 1024;
 
        /* Allocate memory (instead of using a temporary file) */
        temp_file = (char *)mg_calloc((size_t)temp_buf_len, 1);
        if (!temp_file) {
            /* Out of memory */
            return 0;
        }
 
        /* File exists. Read it into a memory buffer. */
        fp = fopen(fname, "r");
        if (fp == NULL) {
            /* Cannot read file. No permission? */
            mg_free(temp_file);
            return 0;
        }
 
        /* Read content and store in memory */
        while ((fgets(line, sizeof(line), fp) != NULL)
               && ((temp_file_offs + 600) < temp_buf_len)) {
            /* file format is "user:domain:hash\n" */
            if (sscanf(line, "%255[^:]:%255[^:]:%255s", u, d, h) != 3) {
                continue;
            }
            u[255] = 0;
            d[255] = 0;
            h[255] = 0;
 
            if (!strcmp(u, user) && !strcmp(d, domain)) {
                /* Found the user: change the password hash or drop the user
                 */
                if ((ha1 != NULL) && (!found)) {
                    i = sprintf(temp_file + temp_file_offs,
                                "%s:%s:%s\n",
                                user,
                                domain,
                                ha1);
                    if (i < 1) {
                        fclose(fp);
                        mg_free(temp_file);
                        return 0;
                    }
                    temp_file_offs += i;
                }
                found = 1;
            } else {
                /* Copy existing user, including password hash */
                i = sprintf(temp_file + temp_file_offs, "%s:%s:%s\n", u, d, h);
                if (i < 1) {
                    fclose(fp);
                    mg_free(temp_file);
                    return 0;
                }
                temp_file_offs += i;
            }
        }
        fclose(fp);
    }
 
    /* Create new file */
    fp = fopen(fname, "w");
    if (!fp) {
        mg_free(temp_file);
        return 0;
    }
 
#if !defined(_WIN32)
    /* On Linux & co., restrict file read/write permissions to the owner */
    if (fchmod(fileno(fp), S_IRUSR | S_IWUSR) != 0) {
        result = 0;
    }
#endif
 
    if ((temp_file != NULL) && (temp_file_offs > 0)) {
        /* Store buffered content of old file */
        if (fwrite(temp_file, 1, (size_t)temp_file_offs, fp)
            != (size_t)temp_file_offs) {
            result = 0;
        }
    }
 
    /* If new user, just add it */
    if ((ha1 != NULL) && (!found)) {
        if (fprintf(fp, "%s:%s:%s\n", user, domain, ha1) < 6) {
            result = 0;
        }
    }
 
    /* All data written */
    if (fclose(fp) != 0) {
        result = 0;
    }
 
    mg_free(temp_file);
    return result;
}
 
 
CIVETWEB_API int
mg_modify_passwords_file(const char *fname,
                         const char *domain,
                         const char *user,
                         const char *pass)
{
    char ha1buf[33];
    if ((fname == NULL) || (domain == NULL) || (user == NULL)) {
        return 0;
    }
    if ((pass == NULL) || (pass[0] == 0)) {
        return mg_modify_passwords_file_ha1(fname, domain, user, NULL);
    }
 
    mg_md5(ha1buf, user, ":", domain, ":", pass, NULL);
    return mg_modify_passwords_file_ha1(fname, domain, user, ha1buf);
}
 
 
static int
is_valid_port(unsigned long port)
{
    return (port <= 0xffff);
}
 
 
static int
mg_inet_pton(int af, const char *src, void *dst, size_t dstlen, int resolve_src)
{
    struct addrinfo hints, *res, *ressave;
    int func_ret = 0;
    int gai_ret;
 
    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = af;
    if (!resolve_src) {
        hints.ai_flags = AI_NUMERICHOST;
    }
 
    gai_ret = getaddrinfo(src, NULL, &hints, &res);
    if (gai_ret != 0) {
        /* gai_strerror could be used to convert gai_ret to a string */
        /* POSIX return values: see
         * http://pubs.opengroup.org/onlinepubs/9699919799/functions/freeaddrinfo.html
         */
        /* Windows return values: see
         * https://msdn.microsoft.com/en-us/library/windows/desktop/ms738520%28v=vs.85%29.aspx
         */
        return 0;
    }
 
    ressave = res;
 
    while (res) {
        if ((dstlen >= (size_t)res->ai_addrlen)
            && (res->ai_addr->sa_family == af)) {
            memcpy(dst, res->ai_addr, res->ai_addrlen);
            func_ret = 1;
        }
        res = res->ai_next;
    }
 
    freeaddrinfo(ressave);
    return func_ret;
}
 
 
static int
connect_socket(
    struct mg_context *ctx /* may be NULL */,
    const char *host,
    int port,    /* 1..65535, or -99 for domain sockets (may be changed) */
    int use_ssl, /* 0 or 1 */
    struct mg_error_data *error,
    SOCKET *sock /* output: socket, must not be NULL */,
    union usa *sa /* output: socket address, must not be NULL  */
)
{
    int ip_ver = 0;
    int conn_ret = -1;
    int sockerr = 0;
    *sock = INVALID_SOCKET;
    memset(sa, 0, sizeof(*sa));
 
    if (host == NULL) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "NULL host");
        }
        return 0;
    }
 
#if defined(USE_X_DOM_SOCKET)
    if (port == -99) {
        /* Unix domain socket */
        size_t hostlen = strlen(host);
        if (hostlen >= sizeof(sa->sun.sun_path)) {
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for ebuf */
                            error->text,
                            error->text_buffer_size,
                            "%s",
                            "host length exceeds limit");
            }
            return 0;
        }
    } else
#endif
        if ((port <= 0) || !is_valid_port((unsigned)port)) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "invalid port");
        }
        return 0;
    }
 
#if !defined(NO_SSL) && !defined(USE_MBEDTLS) && !defined(NO_SSL_DL)
#if defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0)
    if (use_ssl && (TLS_client_method == NULL)) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_LIBRARY_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "SSL is not initialized");
        }
        return 0;
    }
#else
    if (use_ssl && (SSLv23_client_method == NULL)) {
        if (error != 0) {
            error->code = MG_ERROR_DATA_CODE_INIT_LIBRARY_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "SSL is not initialized");
        }
        return 0;
    }
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0*/
#else
    (void)use_ssl;
#endif /* NO SSL */
 
#if defined(USE_X_DOM_SOCKET)
    if (port == -99) {
        size_t hostlen = strlen(host);
        /* check (hostlen < sizeof(sun.sun_path)) already passed above */
        ip_ver = -99;
        sa->sun.sun_family = AF_UNIX;
        memset(sa->sun.sun_path, 0, sizeof(sa->sun.sun_path));
        memcpy(sa->sun.sun_path, host, hostlen);
    } else
#endif
        if (mg_inet_pton(AF_INET, host, &sa->sin, sizeof(sa->sin), 1)) {
        sa->sin.sin_port = htons((uint16_t)port);
        ip_ver = 4;
#if defined(USE_IPV6)
    } else if (mg_inet_pton(AF_INET6, host, &sa->sin6, sizeof(sa->sin6), 1)) {
        sa->sin6.sin6_port = htons((uint16_t)port);
        ip_ver = 6;
    } else if (host[0] == '[') {
        /* While getaddrinfo on Windows will work with [::1],
         * getaddrinfo on Linux only works with ::1 (without []). */
        size_t l = strlen(host + 1);
        char *h = (l > 1) ? mg_strdup_ctx(host + 1, ctx) : NULL;
        if (h) {
            h[l - 1] = 0;
            if (mg_inet_pton(AF_INET6, h, &sa->sin6, sizeof(sa->sin6), 0)) {
                sa->sin6.sin6_port = htons((uint16_t)port);
                ip_ver = 6;
            }
            mg_free(h);
        }
#endif
    }
 
    if (ip_ver == 0) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_HOST_NOT_FOUND;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "host not found");
        }
        return 0;
    }
 
    if (ip_ver == 4) {
        *sock = socket(PF_INET, SOCK_STREAM, 0);
    }
#if defined(USE_IPV6)
    else if (ip_ver == 6) {
        *sock = socket(PF_INET6, SOCK_STREAM, 0);
    }
#endif
#if defined(USE_X_DOM_SOCKET)
    else if (ip_ver == -99) {
        *sock = socket(AF_UNIX, SOCK_STREAM, 0);
    }
#endif
 
    if (*sock == INVALID_SOCKET) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OS_ERROR;
            error->code_sub = (unsigned)ERRNO;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "socket(): %s",
                        strerror(ERRNO));
        }
        return 0;
    }
 
    if (0 != set_non_blocking_mode(*sock)) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OS_ERROR;
            error->code_sub = (unsigned)ERRNO;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "Cannot set socket to non-blocking: %s",
                        strerror(ERRNO));
        }
        closesocket(*sock);
        *sock = INVALID_SOCKET;
        return 0;
    }
 
    set_close_on_exec(*sock, NULL, ctx);
 
    if (ip_ver == 4) {
        /* connected with IPv4 */
        conn_ret = connect(*sock,
                           (struct sockaddr *)((void *)&sa->sin),
                           sizeof(sa->sin));
    }
#if defined(USE_IPV6)
    else if (ip_ver == 6) {
        /* connected with IPv6 */
        conn_ret = connect(*sock,
                           (struct sockaddr *)((void *)&sa->sin6),
                           sizeof(sa->sin6));
    }
#endif
#if defined(USE_X_DOM_SOCKET)
    else if (ip_ver == -99) {
        /* connected to domain socket */
        conn_ret = connect(*sock,
                           (struct sockaddr *)((void *)&sa->sun),
                           sizeof(sa->sun));
    }
#endif
 
    if (conn_ret != 0) {
        sockerr = ERRNO;
    }
 
#if defined(_WIN32)
    if ((conn_ret != 0) && (sockerr == WSAEWOULDBLOCK)) {
#else
    if ((conn_ret != 0) && (sockerr == EINPROGRESS)) {
#endif
        /* Data for getsockopt */
        void *psockerr = &sockerr;
        int ret;
 
#if defined(_WIN32)
        int len = (int)sizeof(sockerr);
#else
        socklen_t len = (socklen_t)sizeof(sockerr);
#endif
 
        /* Data for poll */
        struct mg_pollfd pfd[1];
        int pollres;
        int ms_wait = 10000; /* 10 second timeout */
        stop_flag_t nonstop;
        STOP_FLAG_ASSIGN(&nonstop, 0);
 
        /* For a non-blocking socket, the connect sequence is:
         * 1) call connect (will not block)
         * 2) wait until the socket is ready for writing (select or poll)
         * 3) check connection state with getsockopt
         */
        pfd[0].fd = *sock;
        pfd[0].events = POLLOUT;
        pollres = mg_poll(pfd, 1, ms_wait, ctx ? &(ctx->stop_flag) : &nonstop);
 
        if (pollres != 1) {
            /* Not connected */
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_CONNECT_TIMEOUT;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for ebuf */
                            error->text,
                            error->text_buffer_size,
                            "connect(%s:%d): timeout",
                            host,
                            port);
            }
            closesocket(*sock);
            *sock = INVALID_SOCKET;
            return 0;
        }
 
#if defined(_WIN32)
        ret = getsockopt(*sock, SOL_SOCKET, SO_ERROR, (char *)psockerr, &len);
#else
        ret = getsockopt(*sock, SOL_SOCKET, SO_ERROR, psockerr, &len);
#endif
 
        if ((ret == 0) && (sockerr == 0)) {
            conn_ret = 0;
        }
    }
 
    if (conn_ret != 0) {
        /* Not connected */
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_CONNECT_FAILED;
            error->code_sub = (unsigned)ERRNO;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "connect(%s:%d): error %s",
                        host,
                        port,
                        strerror(sockerr));
        }
        closesocket(*sock);
        *sock = INVALID_SOCKET;
        return 0;
    }
 
    return 1;
}
 
 
CIVETWEB_API int
mg_url_encode(const char *src, char *dst, size_t dst_len)
{
    static const char *dont_escape = "._-$,;~()";
    static const char *hex = "0123456789abcdef";
    char *pos = dst;
    const char *end = dst + dst_len - 1;
 
    for (; ((*src != '\0') && (pos < end)); src++, pos++) {
        if (isalnum((unsigned char)*src)
            || (strchr(dont_escape, *src) != NULL)) {
            *pos = *src;
        } else if (pos + 2 < end) {
            pos[0] = '%';
            pos[1] = hex[(unsigned char)*src >> 4];
            pos[2] = hex[(unsigned char)*src & 0xf];
            pos += 2;
        } else {
            break;
        }
    }
 
    *pos = '\0';
    return (*src == '\0') ? (int)(pos - dst) : -1;
}
 
/* Return 0 on success, non-zero if an error occurs. */
 
static int
print_dir_entry(struct mg_connection *conn, struct de *de)
{
    size_t namesize, escsize, i;
    char *href, *esc, *p;
    char size[64], mod[64];
#if defined(REENTRANT_TIME)
    struct tm _tm;
    struct tm *tm = &_tm;
#else
    struct tm *tm;
#endif
 
    /* Estimate worst case size for encoding and escaping */
    namesize = strlen(de->file_name) + 1;
    escsize = de->file_name[strcspn(de->file_name, "&<>")] ? namesize * 5 : 0;
    href = (char *)mg_malloc(namesize * 3 + escsize);
    if (href == NULL) {
        return -1;
    }
    mg_url_encode(de->file_name, href, namesize * 3);
    esc = NULL;
    if (escsize > 0) {
        /* HTML escaping needed */
        esc = href + namesize * 3;
        for (i = 0, p = esc; de->file_name[i]; i++, p += strlen(p)) {
            mg_strlcpy(p, de->file_name + i, 2);
            if (*p == '&') {
                strcpy(p, "&amp;");
            } else if (*p == '<') {
                strcpy(p, "&lt;");
            } else if (*p == '>') {
                strcpy(p, "&gt;");
            }
        }
    }
 
    if (de->file.is_directory) {
        mg_snprintf(conn,
                    NULL, /* Buffer is big enough */
                    size,
                    sizeof(size),
                    "%s",
                    "[DIRECTORY]");
    } else {
        /* We use (signed) cast below because MSVC 6 compiler cannot
         * convert unsigned __int64 to double. Sigh. */
        if (de->file.size < 1024) {
            mg_snprintf(conn,
                        NULL, /* Buffer is big enough */
                        size,
                        sizeof(size),
                        "%d",
                        (int)de->file.size);
        } else if (de->file.size < 0x100000) {
            mg_snprintf(conn,
                        NULL, /* Buffer is big enough */
                        size,
                        sizeof(size),
                        "%.1fk",
                        (double)de->file.size / 1024.0);
        } else if (de->file.size < 0x40000000) {
            mg_snprintf(conn,
                        NULL, /* Buffer is big enough */
                        size,
                        sizeof(size),
                        "%.1fM",
                        (double)de->file.size / 1048576);
        } else {
            mg_snprintf(conn,
                        NULL, /* Buffer is big enough */
                        size,
                        sizeof(size),
                        "%.1fG",
                        (double)de->file.size / 1073741824);
        }
    }
 
    /* Note: mg_snprintf will not cause a buffer overflow above.
     * So, string truncation checks are not required here. */
 
#if defined(REENTRANT_TIME)
    localtime_r(&de->file.last_modified, tm);
#else
    tm = localtime(&de->file.last_modified);
#endif
    if (tm != NULL) {
        strftime(mod, sizeof(mod), "%d-%b-%Y %H:%M", tm);
    } else {
        mg_strlcpy(mod, "01-Jan-1970 00:00", sizeof(mod));
    }
    mg_printf(conn,
              "<tr><td><a href=\"%s%s\">%s%s</a></td>"
              "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
              href,
              de->file.is_directory ? "/" : "",
              esc ? esc : de->file_name,
              de->file.is_directory ? "/" : "",
              mod,
              size);
    mg_free(href);
    return 0;
}
 
 
/* This function is called from send_directory() and used for
 * sorting directory entries by size, name, or modification time. */
static int
compare_dir_entries(const void *p1, const void *p2, void *arg)
{
    const char *query_string = (const char *)(arg != NULL ? arg : "");
    if (p1 && p2) {
        const struct de *a = (const struct de *)p1, *b = (const struct de *)p2;
        int cmp_result = 0;
 
        if ((query_string == NULL) || (query_string[0] == '\0')) {
            query_string = "n";
        }
 
        /* Sort Directories vs Files */
        if (a->file.is_directory && !b->file.is_directory) {
            return -1; /* Always put directories on top */
        } else if (!a->file.is_directory && b->file.is_directory) {
            return 1; /* Always put directories on top */
        }
 
        /* Sort by size or date */
        if (*query_string == 's') {
            cmp_result = (a->file.size == b->file.size)
                             ? 0
                             : ((a->file.size > b->file.size) ? 1 : -1);
        } else if (*query_string == 'd') {
            cmp_result =
                (a->file.last_modified == b->file.last_modified)
                    ? 0
                    : ((a->file.last_modified > b->file.last_modified) ? 1
                                                                       : -1);
        }
 
        /* Sort by name:
         * if (*query_string == 'n')  ...
         * but also sort files of same size/date by name as secondary criterion.
         */
        if (cmp_result == 0) {
            cmp_result = strcmp(a->file_name, b->file_name);
        }
 
        /* For descending order, invert result */
        return (query_string[1] == 'd') ? -cmp_result : cmp_result;
    }
    return 0;
}
 
 
static int
must_hide_file(struct mg_connection *conn, const char *path)
{
    if (conn && conn->dom_ctx) {
        const char *pw_pattern = "**" PASSWORDS_FILE_NAME "$";
        const char *pattern = conn->dom_ctx->config[HIDE_FILES];
        return (match_prefix_strlen(pw_pattern, path) > 0)
               || (match_prefix_strlen(pattern, path) > 0);
    }
    return 0;
}
 
 
#if !defined(NO_FILESYSTEMS)
static int
scan_directory(struct mg_connection *conn,
               const char *dir,
               void *data,
               int (*cb)(struct de *, void *))
{
    char path[UTF8_PATH_MAX];
    struct dirent *dp;
    DIR *dirp;
    struct de de;
    int truncated;
 
    if ((dirp = mg_opendir(conn, dir)) == NULL) {
        return 0;
    } else {
 
        while ((dp = mg_readdir(dirp)) != NULL) {
            /* Do not show current dir and hidden files */
            if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")
                || must_hide_file(conn, dp->d_name)) {
                continue;
            }
 
            mg_snprintf(
                conn, &truncated, path, sizeof(path), "%s/%s", dir, dp->d_name);
 
            /* If we don't memset stat structure to zero, mtime will have
             * garbage and strftime() will segfault later on in
             * print_dir_entry(). memset is required only if mg_stat()
             * fails. For more details, see
             * http://code.google.com/p/mongoose/issues/detail?id=79 */
            memset(&de.file, 0, sizeof(de.file));
 
            if (truncated) {
                /* If the path is not complete, skip processing. */
                continue;
            }
 
            if (!mg_stat(conn, path, &de.file)) {
                mg_cry_internal(conn,
                                "%s: mg_stat(%s) failed: %s",
                                __func__,
                                path,
                                strerror(ERRNO));
            }
            de.file_name = dp->d_name;
            if (cb(&de, data)) {
                /* stopped */
                break;
            }
        }
        (void)mg_closedir(dirp);
    }
    return 1;
}
#endif /* NO_FILESYSTEMS */
 
 
#if !defined(NO_FILES)
static int
remove_directory(struct mg_connection *conn, const char *dir)
{
    char path[UTF8_PATH_MAX];
    struct dirent *dp;
    DIR *dirp;
    struct de de;
    int truncated;
    int ok = 1;
 
    if ((dirp = mg_opendir(conn, dir)) == NULL) {
        return 0;
    } else {
 
        while ((dp = mg_readdir(dirp)) != NULL) {
            /* Do not show current dir (but show hidden files as they will
             * also be removed) */
            if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, "..")) {
                continue;
            }
 
            mg_snprintf(
                conn, &truncated, path, sizeof(path), "%s/%s", dir, dp->d_name);
 
            /* If we don't memset stat structure to zero, mtime will have
             * garbage and strftime() will segfault later on in
             * print_dir_entry(). memset is required only if mg_stat()
             * fails. For more details, see
             * http://code.google.com/p/mongoose/issues/detail?id=79 */
            memset(&de.file, 0, sizeof(de.file));
 
            if (truncated) {
                /* Do not delete anything shorter */
                ok = 0;
                continue;
            }
 
            if (!mg_stat(conn, path, &de.file)) {
                mg_cry_internal(conn,
                                "%s: mg_stat(%s) failed: %s",
                                __func__,
                                path,
                                strerror(ERRNO));
                ok = 0;
            }
 
            if (de.file.is_directory) {
                if (remove_directory(conn, path) == 0) {
                    ok = 0;
                }
            } else {
                /* This will fail file is the file is in memory */
                if (mg_remove(conn, path) == 0) {
                    ok = 0;
                }
            }
        }
        (void)mg_closedir(dirp);
 
        IGNORE_UNUSED_RESULT(rmdir(dir));
    }
 
    return ok;
}
#endif
 
 
struct dir_scan_data {
    struct de *entries;
    size_t num_entries;
    size_t arr_size;
};
 
 
#if !defined(NO_FILESYSTEMS)
static int
dir_scan_callback(struct de *de, void *data)
{
    struct dir_scan_data *dsd = (struct dir_scan_data *)data;
    struct de *entries = dsd->entries;
 
    if ((entries == NULL) || (dsd->num_entries >= dsd->arr_size)) {
        /* Here "entries" is a temporary pointer and can be replaced,
         * "dsd->entries" is the original pointer */
        entries =
            (struct de *)mg_realloc(entries,
                                    dsd->arr_size * 2 * sizeof(entries[0]));
        if (entries == NULL) {
            /* stop scan */
            return 1;
        }
        dsd->entries = entries;
        dsd->arr_size *= 2;
    }
    entries[dsd->num_entries].file_name = mg_strdup(de->file_name);
    if (entries[dsd->num_entries].file_name == NULL) {
        /* stop scan */
        return 1;
    }
    entries[dsd->num_entries].file = de->file;
    dsd->num_entries++;
 
    return 0;
}
 
 
static void
handle_directory_request(struct mg_connection *conn, const char *dir)
{
    size_t i;
    int sort_direction;
    struct dir_scan_data data = {NULL, 0, 128};
    char date[64], *esc, *p;
    const char *title;
    time_t curtime = time(NULL);
 
    if (!conn) {
        return;
    }
 
    if (!scan_directory(conn, dir, &data, dir_scan_callback)) {
        mg_send_http_error(conn,
                           500,
                           "Error: Cannot open directory\nopendir(%s): %s",
                           dir,
                           strerror(ERRNO));
        return;
    }
 
    gmt_time_string(date, sizeof(date), &curtime);
 
    esc = NULL;
    title = conn->request_info.local_uri;
    if (title[strcspn(title, "&<>")]) {
        /* HTML escaping needed */
        esc = (char *)mg_malloc(strlen(title) * 5 + 1);
        if (esc) {
            for (i = 0, p = esc; title[i]; i++, p += strlen(p)) {
                mg_strlcpy(p, title + i, 2);
                if (*p == '&') {
                    strcpy(p, "&amp;");
                } else if (*p == '<') {
                    strcpy(p, "&lt;");
                } else if (*p == '>') {
                    strcpy(p, "&gt;");
                }
            }
        } else {
            title = "";
        }
    }
 
    sort_direction = ((conn->request_info.query_string != NULL)
                      && (conn->request_info.query_string[0] != '\0')
                      && (conn->request_info.query_string[1] == 'd'))
                         ? 'a'
                         : 'd';
 
    conn->must_close = 1;
 
    /* Create 200 OK response */
    mg_response_header_start(conn, 200);
    send_static_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn,
                           "Content-Type",
                           "text/html; charset=utf-8",
                           -1);
 
    /* Send all headers */
    mg_response_header_send(conn);
 
    /* Body */
    mg_printf(conn,
              "<!DOCTYPE html>"
              "<html><head><title>Index of %s</title>"
              "<style>th {text-align: left;}</style></head>"
              "<body><h1>Index of %s</h1><pre><table cellpadding=\"0\">"
              "<tr><th><a href=\"?n%c\">Name</a></th>"
              "<th><a href=\"?d%c\">Modified</a></th>"
              "<th><a href=\"?s%c\">Size</a></th></tr>"
              "<tr><td colspan=\"3\"><hr></td></tr>",
              esc ? esc : title,
              esc ? esc : title,
              sort_direction,
              sort_direction,
              sort_direction);
    mg_free(esc);
 
    /* Print first entry - link to a parent directory */
    mg_printf(conn,
              "<tr><td><a href=\"%s\">%s</a></td>"
              "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
              "..",
              "Parent directory",
              "-",
              "-");
 
    /* Sort and print directory entries */
    if (data.entries != NULL) {
        mg_sort(data.entries,
                data.num_entries,
                sizeof(data.entries[0]),
                compare_dir_entries,
                (void *)conn->request_info.query_string);
        for (i = 0; i < data.num_entries; i++) {
            print_dir_entry(conn, &data.entries[i]);
            mg_free(data.entries[i].file_name);
        }
        mg_free(data.entries);
    }
 
    mg_printf(conn, "%s", "</table></pre></body></html>");
    conn->status_code = 200;
}
#endif /* NO_FILESYSTEMS */
 
 
/* Send len bytes from the opened file to the client. */
static void
send_file_data(struct mg_connection *conn,
               struct mg_file *filep,
               int64_t offset,
               int64_t len,
               int no_buffering)
{
    char buf[MG_BUF_LEN];
    int to_read, num_read, num_written;
    int64_t size;
 
    if (!filep || !conn) {
        return;
    }
 
    /* Sanity check the offset */
    size = (filep->stat.size > INT64_MAX) ? INT64_MAX
                                          : (int64_t)(filep->stat.size);
    offset = (offset < 0) ? 0 : ((offset > size) ? size : offset);
 
    if (len > 0 && filep->access.fp != NULL) {
        /* file stored on disk */
#if defined(__linux__)
        /* sendfile is only available for Linux */
        if ((conn->ssl == 0) && (conn->throttle == 0)
            && (!mg_strcasecmp(conn->dom_ctx->config[ALLOW_SENDFILE_CALL],
                               "yes"))) {
            off_t sf_offs = (off_t)offset;
            ssize_t sf_sent;
            int sf_file = fileno(filep->access.fp);
            int loop_cnt = 0;
 
            do {
                /* 2147479552 (0x7FFFF000) is a limit found by experiment on
                 * 64 bit Linux (2^31 minus one memory page of 4k?). */
                size_t sf_tosend =
                    (size_t)((len < 0x7FFFF000) ? len : 0x7FFFF000);
                sf_sent =
                    sendfile(conn->client.sock, sf_file, &sf_offs, sf_tosend);
                if (sf_sent > 0) {
                    len -= sf_sent;
                    offset += sf_sent;
                } else if (loop_cnt == 0) {
                    /* This file can not be sent using sendfile.
                     * This might be the case for pseudo-files in the
                     * /sys/ and /proc/ file system.
                     * Use the regular user mode copy code instead. */
                    break;
                } else if (sf_sent == 0) {
                    /* No error, but 0 bytes sent. May be EOF? */
                    return;
                }
                loop_cnt++;
 
            } while ((len > 0) && (sf_sent >= 0));
 
            if (sf_sent > 0) {
                return; /* OK */
            }
 
            /* sf_sent<0 means error, thus fall back to the classic way */
            /* This is always the case, if sf_file is not a "normal" file,
             * e.g., for sending data from the output of a CGI process. */
            offset = (int64_t)sf_offs;
        }
#endif
        if ((offset > 0) && (fseeko(filep->access.fp, offset, SEEK_SET) != 0)) {
            mg_cry_internal(conn,
                            "%s: fseeko() failed: %s",
                            __func__,
                            strerror(ERRNO));
            mg_send_http_error(
                conn,
                500,
                "%s",
                "Error: Unable to access file at requested position.");
        } else {
            while (len > 0) {
                /* Calculate how much to read from the file into the buffer. */
                /* If no_buffering is set, we should not wait until the
                 * CGI->Server buffer is filled, but send everything
                 * immediately. In theory buffering could be turned off using
                 * setbuf(filep->access.fp, NULL);
                 * setvbuf(filep->access.fp, NULL, _IONBF, 0);
                 * but in practice this does not work. A "Linux only" solution
                 * may be to use select(). The only portable way is to read byte
                 * by byte, but this is quite inefficient from a performance
                 * point of view. */
                to_read = no_buffering ? 1 : sizeof(buf);
                if ((int64_t)to_read > len) {
                    to_read = (int)len;
                }
 
                /* Read from file, exit the loop on error */
                if ((num_read =
                         (int)fread(buf, 1, (size_t)to_read, filep->access.fp))
                    <= 0) {
                    break;
                }
 
                /* Send read bytes to the client, exit the loop on error */
                if ((num_written = mg_write(conn, buf, (size_t)num_read))
                    != num_read) {
                    break;
                }
 
                /* Both read and were successful, adjust counters */
                len -= num_written;
            }
        }
    }
}
 
 
static int
parse_range_header(const char *header, int64_t *a, int64_t *b)
{
    return sscanf(header,
                  "bytes=%" INT64_FMT "-%" INT64_FMT,
                  a,
                  b); // NOLINT(cert-err34-c) 'sscanf' used to convert a string
                      // to an integer value, but function will not report
                      // conversion errors; consider using 'strtol' instead
}
 
 
static void
construct_etag(char *buf, size_t buf_len, const struct mg_file_stat *filestat)
{
    if ((filestat != NULL) && (buf != NULL)) {
        mg_snprintf(NULL,
                    NULL, /* All calls to construct_etag use 64 byte buffer */
                    buf,
                    buf_len,
                    "\"%lx.%" INT64_FMT "\"",
                    (unsigned long)filestat->last_modified,
                    filestat->size);
    }
}
 
 
static void
fclose_on_exec(struct mg_file_access *filep, struct mg_connection *conn)
{
    if (filep != NULL && filep->fp != NULL) {
#if defined(_WIN32)
        (void)conn; /* Unused. */
#else
        if (fcntl(fileno(filep->fp), F_SETFD, FD_CLOEXEC) != 0) {
            mg_cry_internal(conn,
                            "%s: fcntl(F_SETFD FD_CLOEXEC) failed: %s",
                            __func__,
                            strerror(ERRNO));
        }
#endif
    }
}
 
 
#if defined(USE_ZLIB)
#include "mod_zlib.inl"
#endif
 
 
#if !defined(NO_FILESYSTEMS)
static void
handle_static_file_request(struct mg_connection *conn,
                           const char *path,
                           struct mg_file *filep,
                           const char *mime_type,
                           const char *additional_headers)
{
    char lm[64], etag[64];
    char range[128]; /* large enough, so there will be no overflow */
    const char *range_hdr;
    int64_t cl, r1, r2;
    struct vec mime_vec;
    int n, truncated;
    char gz_path[UTF8_PATH_MAX];
    const char *encoding = 0;
    int is_head_request;
 
#if defined(USE_ZLIB)
    /* Compression is allowed, unless there is a reason not to use
     * compression. If the file is already compressed, too small or a
     * "range" request was made, on the fly compression is not possible. */
    int allow_on_the_fly_compression = 1;
#endif
 
    if ((conn == NULL) || (conn->dom_ctx == NULL) || (filep == NULL)) {
        return;
    }
 
    is_head_request = !strcmp(conn->request_info.request_method, "HEAD");
 
    if (mime_type == NULL) {
        get_mime_type(conn, path, &mime_vec);
    } else {
        mime_vec.ptr = mime_type;
        mime_vec.len = strlen(mime_type);
    }
    if (filep->stat.size > INT64_MAX) {
        mg_send_http_error(conn,
                           500,
                           "Error: File size is too large to send\n%" INT64_FMT,
                           filep->stat.size);
        return;
    }
    cl = (int64_t)filep->stat.size;
    conn->status_code = 200;
    range[0] = '\0';
 
#if defined(USE_ZLIB)
    /* if this file is in fact a pre-gzipped file, rewrite its filename
     * it's important to rewrite the filename after resolving
     * the mime type from it, to preserve the actual file's type */
    if (!conn->accept_gzip) {
        allow_on_the_fly_compression = 0;
    }
#endif
 
    /* Check if there is a range header */
    range_hdr = mg_get_header(conn, "Range");
 
    /* For gzipped files, add *.gz */
    if (filep->stat.is_gzipped) {
        mg_snprintf(conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", path);
 
        if (truncated) {
            mg_send_http_error(conn,
                               500,
                               "Error: Path of zipped file too long (%s)",
                               path);
            return;
        }
 
        path = gz_path;
        encoding = "gzip";
 
#if defined(USE_ZLIB)
        /* File is already compressed. No "on the fly" compression. */
        allow_on_the_fly_compression = 0;
#endif
    } else if ((conn->accept_gzip) && (range_hdr == NULL)
               && (filep->stat.size >= MG_FILE_COMPRESSION_SIZE_LIMIT)) {
        struct mg_file_stat file_stat;
 
        mg_snprintf(conn, &truncated, gz_path, sizeof(gz_path), "%s.gz", path);
 
        if (!truncated && mg_stat(conn, gz_path, &file_stat)
            && !file_stat.is_directory) {
            file_stat.is_gzipped = 1;
            filep->stat = file_stat;
            cl = (int64_t)filep->stat.size;
            path = gz_path;
            encoding = "gzip";
 
#if defined(USE_ZLIB)
            /* File is already compressed. No "on the fly" compression. */
            allow_on_the_fly_compression = 0;
#endif
        }
    }
 
    if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, filep)) {
        mg_send_http_error(conn,
                           500,
                           "Error: Cannot open file\nfopen(%s): %s",
                           path,
                           strerror(ERRNO));
        return;
    }
 
    fclose_on_exec(&filep->access, conn);
 
    /* If "Range" request was made: parse header, send only selected part
     * of the file. */
    r1 = r2 = 0;
    if ((range_hdr != NULL)
        && ((n = parse_range_header(range_hdr, &r1, &r2)) > 0) && (r1 >= 0)
        && (r2 >= 0)) {
        /* actually, range requests don't play well with a pre-gzipped
         * file (since the range is specified in the uncompressed space) */
        if (filep->stat.is_gzipped) {
            mg_send_http_error(
                conn,
                416, /* 416 = Range Not Satisfiable */
                "%s",
                "Error: Range requests in gzipped files are not supported");
            (void)mg_fclose(
                &filep->access); /* ignore error on read only file */
            return;
        }
        conn->status_code = 206;
        cl = (n == 2) ? (((r2 > cl) ? cl : r2) - r1 + 1) : (cl - r1);
        mg_snprintf(conn,
                    NULL, /* range buffer is big enough */
                    range,
                    sizeof(range),
                    "bytes "
                    "%" INT64_FMT "-%" INT64_FMT "/%" INT64_FMT,
                    r1,
                    r1 + cl - 1,
                    filep->stat.size);
 
#if defined(USE_ZLIB)
        /* Do not compress ranges. */
        allow_on_the_fly_compression = 0;
#endif
    }
 
    /* Do not compress small files. Small files do not benefit from file
     * compression, but there is still some overhead. */
#if defined(USE_ZLIB)
    if (filep->stat.size < MG_FILE_COMPRESSION_SIZE_LIMIT) {
        /* File is below the size limit. */
        allow_on_the_fly_compression = 0;
    }
#endif
 
    /* Prepare Etag, and Last-Modified headers. */
    gmt_time_string(lm, sizeof(lm), &filep->stat.last_modified);
    construct_etag(etag, sizeof(etag), &filep->stat);
 
    /* Create 2xx (200, 206) response */
    mg_response_header_start(conn, conn->status_code);
    send_static_cache_header(conn);
    send_additional_header(conn);
    send_cors_header(conn);
    mg_response_header_add(conn,
                           "Content-Type",
                           mime_vec.ptr,
                           (int)mime_vec.len);
    mg_response_header_add(conn, "Last-Modified", lm, -1);
    mg_response_header_add(conn, "Etag", etag, -1);
 
#if defined(USE_ZLIB)
    /* On the fly compression allowed */
    if (allow_on_the_fly_compression) {
        /* For on the fly compression, we don't know the content size in
         * advance, so we have to use chunked encoding */
        encoding = "gzip";
        if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
            /* HTTP/2 is always using "chunks" (frames) */
            mg_response_header_add(conn, "Transfer-Encoding", "chunked", -1);
        }
 
    } else
#endif
    {
        /* Without on-the-fly compression, we know the content-length
         * and we can use ranges (with on-the-fly compression we cannot).
         * So we send these response headers only in this case. */
        char len[32];
        int trunc = 0;
        mg_snprintf(conn, &trunc, len, sizeof(len), "%" INT64_FMT, cl);
 
        if (!trunc) {
            mg_response_header_add(conn, "Content-Length", len, -1);
        }
 
        mg_response_header_add(conn, "Accept-Ranges", "bytes", -1);
    }
 
    if (encoding) {
        mg_response_header_add(conn, "Content-Encoding", encoding, -1);
    }
    if (range[0] != 0) {
        mg_response_header_add(conn, "Content-Range", range, -1);
    }
 
    /* The code above does not add any header starting with X- to make
     * sure no one of the additional_headers is included twice */
    if ((additional_headers != NULL) && (*additional_headers != 0)) {
        mg_response_header_add_lines(conn, additional_headers);
    }
 
    /* Send all headers */
    mg_response_header_send(conn);
 
    if (!is_head_request) {
#if defined(USE_ZLIB)
        if (allow_on_the_fly_compression) {
            /* Compress and send */
            send_compressed_data(conn, filep);
        } else
#endif
        {
            /* Send file directly */
            send_file_data(conn, filep, r1, cl, 0); /* send static file */
        }
    }
    (void)mg_fclose(&filep->access); /* ignore error on read only file */
}
 
 
CIVETWEB_API int
mg_send_file_body(struct mg_connection *conn, const char *path)
{
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, &file)) {
        return -1;
    }
    fclose_on_exec(&file.access, conn);
    send_file_data(conn, &file, 0, INT64_MAX, 0); /* send static file */
    (void)mg_fclose(&file.access); /* Ignore errors for readonly files */
    return 0;                      /* >= 0 for OK */
}
#endif /* NO_FILESYSTEMS */
 
 
#if !defined(NO_CACHING)
/* Return True if we should reply 304 Not Modified. */
static int
is_not_modified(const struct mg_connection *conn,
                const struct mg_file_stat *filestat)
{
    char etag[64];
    const char *ims = mg_get_header(conn, "If-Modified-Since");
    const char *inm = mg_get_header(conn, "If-None-Match");
    construct_etag(etag, sizeof(etag), filestat);
 
    return ((inm != NULL) && !mg_strcasecmp(etag, inm))
           || ((ims != NULL)
               && (filestat->last_modified <= parse_date_string(ims)));
}
 
 
static void
handle_not_modified_static_file_request(struct mg_connection *conn,
                                        struct mg_file *filep)
{
    char lm[64], etag[64];
 
    if ((conn == NULL) || (filep == NULL)) {
        return;
    }
 
    gmt_time_string(lm, sizeof(lm), &filep->stat.last_modified);
    construct_etag(etag, sizeof(etag), &filep->stat);
 
    /* Create 304 "not modified" response */
    mg_response_header_start(conn, 304);
    send_static_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn, "Last-Modified", lm, -1);
    mg_response_header_add(conn, "Etag", etag, -1);
 
    /* Send all headers */
    mg_response_header_send(conn);
}
#endif
 
 
#if !defined(NO_FILESYSTEMS)
CIVETWEB_API void
mg_send_file(struct mg_connection *conn, const char *path)
{
    mg_send_mime_file2(conn, path, NULL, NULL);
}
 
 
CIVETWEB_API void
mg_send_mime_file(struct mg_connection *conn,
                  const char *path,
                  const char *mime_type)
{
    mg_send_mime_file2(conn, path, mime_type, NULL);
}
 
 
CIVETWEB_API void
mg_send_mime_file2(struct mg_connection *conn,
                   const char *path,
                   const char *mime_type,
                   const char *additional_headers)
{
    struct mg_file file = STRUCT_FILE_INITIALIZER;
 
    if (!conn) {
        /* No conn */
        return;
    }
 
    if (mg_stat(conn, path, &file.stat)) {
#if !defined(NO_CACHING)
        if (is_not_modified(conn, &file.stat)) {
            /* Send 304 "Not Modified" - this must not send any body data */
            handle_not_modified_static_file_request(conn, &file);
        } else
#endif /* NO_CACHING */
            if (file.stat.is_directory) {
            if (!mg_strcasecmp(conn->dom_ctx->config[ENABLE_DIRECTORY_LISTING],
                               "yes")) {
                handle_directory_request(conn, path);
            } else {
                mg_send_http_error(conn,
                                   403,
                                   "%s",
                                   "Error: Directory listing denied");
            }
        } else {
            handle_static_file_request(
                conn, path, &file, mime_type, additional_headers);
        }
    } else {
        mg_send_http_error(conn, 404, "%s", "Error: File not found");
    }
}
 
 
/* For a given PUT path, create all intermediate subdirectories.
 * Return  0  if the path itself is a directory.
 * Return  1  if the path leads to a file.
 * Return -1  for if the path is too long.
 * Return -2  if path can not be created.
 */
static int
put_dir(struct mg_connection *conn, const char *path)
{
    char buf[UTF8_PATH_MAX];
    const char *s, *p;
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    size_t len;
    int res = 1;
 
    for (s = p = path + 2; (p = strchr(s, '/')) != NULL; s = ++p) {
        len = (size_t)(p - path);
        if (len >= sizeof(buf)) {
            /* path too long */
            res = -1;
            break;
        }
        memcpy(buf, path, len);
        buf[len] = '\0';
 
        /* Try to create intermediate directory */
        DEBUG_TRACE("mkdir(%s)", buf);
        if (!mg_stat(conn, buf, &file.stat) && mg_mkdir(conn, buf, 0755) != 0) {
            /* path does not exist and can not be created */
            res = -2;
            break;
        }
 
        /* Is path itself a directory? */
        if (p[1] == '\0') {
            res = 0;
        }
    }
 
    return res;
}
 
 
static void
remove_bad_file(const struct mg_connection *conn, const char *path)
{
    int r = mg_remove(conn, path);
    if (r != 0) {
        mg_cry_internal(conn,
                        "%s: Cannot remove invalid file %s",
                        __func__,
                        path);
    }
}
 
 
CIVETWEB_API long long
mg_store_body(struct mg_connection *conn, const char *path)
{
    char buf[MG_BUF_LEN];
    long long len = 0;
    int ret, n;
    struct mg_file fi;
 
    if (conn->consumed_content != 0) {
        mg_cry_internal(conn, "%s: Contents already consumed", __func__);
        return -11;
    }
 
    ret = put_dir(conn, path);
    if (ret < 0) {
        /* -1 for path too long,
         * -2 for path can not be created. */
        return ret;
    }
    if (ret != 1) {
        /* Return 0 means, path itself is a directory. */
        return 0;
    }
 
    if (mg_fopen(conn, path, MG_FOPEN_MODE_WRITE, &fi) == 0) {
        return -12;
    }
 
    ret = mg_read(conn, buf, sizeof(buf));
    while (ret > 0) {
        n = (int)fwrite(buf, 1, (size_t)ret, fi.access.fp);
        if (n != ret) {
            (void)mg_fclose(
                &fi.access); /* File is bad and will be removed anyway. */
            remove_bad_file(conn, path);
            return -13;
        }
        len += ret;
        ret = mg_read(conn, buf, sizeof(buf));
    }
 
    /* File is open for writing. If fclose fails, there was probably an
     * error flushing the buffer to disk, so the file on disk might be
     * broken. Delete it and return an error to the caller. */
    if (mg_fclose(&fi.access) != 0) {
        remove_bad_file(conn, path);
        return -14;
    }
 
    return len;
}
#endif /* NO_FILESYSTEMS */
 
 
/* Parse a buffer:
 * Forward the string pointer till the end of a word, then
 * terminate it and forward till the begin of the next word.
 */
static int
skip_to_end_of_word_and_terminate(char **ppw, int eol)
{
    /* Forward until a space is found - use isgraph here */
    /* See http://www.cplusplus.com/reference/cctype/ */
    while (isgraph((unsigned char)**ppw)) {
        (*ppw)++;
    }
 
    /* Check end of word */
    if (eol) {
        /* must be a end of line */
        if ((**ppw != '\r') && (**ppw != '\n')) {
            return -1;
        }
    } else {
        /* must be a end of a word, but not a line */
        if (**ppw != ' ') {
            return -1;
        }
    }
 
    /* Terminate and forward to the next word */
    do {
        **ppw = 0;
        (*ppw)++;
    } while (isspace((unsigned char)**ppw));
 
    /* Check after term */
    if (!eol) {
        /* if it's not the end of line, there must be a next word */
        if (!isgraph((unsigned char)**ppw)) {
            return -1;
        }
    }
 
    /* ok */
    return 1;
}
 
 
/* Parse HTTP headers from the given buffer, advance buf pointer
 * to the point where parsing stopped.
 * All parameters must be valid pointers (not NULL).
 * Return <0 on error. */
static int
parse_http_headers(char **buf, struct mg_header hdr[MG_MAX_HEADERS])
{
    int i;
    int num_headers = 0;
 
    for (i = 0; i < (int)MG_MAX_HEADERS; i++) {
        char *dp = *buf;
 
        /* Skip all ASCII characters (>SPACE, <127), to find a ':' */
        while ((*dp != ':') && (*dp >= 33) && (*dp <= 126)) {
            dp++;
        }
        if (dp == *buf) {
            /* End of headers reached. */
            break;
        }
 
        /* Drop all spaces after header name before : */
        while (*dp == ' ') {
            *dp = 0;
            dp++;
        }
        if (*dp != ':') {
            /* This is not a valid field. */
            return -1;
        }
 
        /* End of header key (*dp == ':') */
        /* Truncate here and set the key name */
        *dp = 0;
        hdr[i].name = *buf;
 
        /* Skip all spaces */
        do {
            dp++;
        } while ((*dp == ' ') || (*dp == '\t'));
 
        /* The rest of the line is the value */
        hdr[i].value = dp;
 
        /* Find end of line */
        while ((*dp != 0) && (*dp != '\r') && (*dp != '\n')) {
            dp++;
        };
 
        /* eliminate \r */
        if (*dp == '\r') {
            *dp = 0;
            dp++;
            if (*dp != '\n') {
                /* This is not a valid line. */
                return -1;
            }
        }
 
        /* here *dp is either 0 or '\n' */
        /* in any case, we have a new header */
        num_headers = i + 1;
 
        if (*dp) {
            *dp = 0;
            dp++;
            *buf = dp;
 
            if ((dp[0] == '\r') || (dp[0] == '\n')) {
                /* This is the end of the header */
                break;
            }
        } else {
            *buf = dp;
            break;
        }
    }
    return num_headers;
}
 
 
struct mg_http_method_info {
    const char *name;
    int request_has_body;
    int response_has_body;
    int is_safe;
    int is_idempotent;
    int is_cacheable;
};
 
 
/* https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods */
static const struct mg_http_method_info http_methods[] = {
    /* HTTP (RFC 2616) */
    {"GET", 0, 1, 1, 1, 1},
    {"POST", 1, 1, 0, 0, 0},
    {"PUT", 1, 0, 0, 1, 0},
    {"DELETE", 0, 0, 0, 1, 0},
    {"HEAD", 0, 0, 1, 1, 1},
    {"OPTIONS", 0, 0, 1, 1, 0},
    {"CONNECT", 1, 1, 0, 0, 0},
    /* TRACE method (RFC 2616) is not supported for security reasons */
 
    /* PATCH method (RFC 5789) */
    {"PATCH", 1, 0, 0, 0, 0},
    /* PATCH method only allowed for CGI/Lua/LSP and callbacks. */
 
    /* WEBDAV (RFC 2518) */
    {"PROPFIND", 0, 1, 1, 1, 0},
    /* http://www.webdav.org/specs/rfc4918.html, 9.1:
     * Some PROPFIND results MAY be cached, with care,
     * as there is no cache validation mechanism for
     * most properties. This method is both safe and
     * idempotent (see Section 9.1 of [RFC2616]). */
    {"MKCOL", 0, 0, 0, 1, 0},
    /* http://www.webdav.org/specs/rfc4918.html, 9.1:
     * When MKCOL is invoked without a request body,
     * the newly created collection SHOULD have no
     * members. A MKCOL request message may contain
     * a message body. The precise behavior of a MKCOL
     * request when the body is present is undefined,
     * ... ==> We do not support MKCOL with body data.
     * This method is idempotent, but not safe (see
     * Section 9.1 of [RFC2616]). Responses to this
     * method MUST NOT be cached. */
 
    /* Methods for write access to files on WEBDAV (RFC 2518) */
    {"LOCK", 1, 1, 0, 0, 0},
    {"UNLOCK", 1, 0, 0, 0, 0},
    {"PROPPATCH", 1, 1, 0, 0, 0},
    {"COPY", 1, 0, 0, 0, 0},
    {"MOVE", 1, 1, 0, 0, 0},
 
    /* Unsupported WEBDAV Methods: */
    /* + 11 methods from RFC 3253 */
    /* ORDERPATCH (RFC 3648) */
    /* ACL (RFC 3744) */
    /* SEARCH (RFC 5323) */
    /* + MicroSoft extensions
     * https://msdn.microsoft.com/en-us/library/aa142917.aspx */
 
    /* REPORT method (RFC 3253) */
    {"REPORT", 1, 1, 1, 1, 1},
    /* REPORT method only allowed for CGI/Lua/LSP and callbacks. */
    /* It was defined for WEBDAV in RFC 3253, Sec. 3.6
     * (https://tools.ietf.org/html/rfc3253#section-3.6), but seems
     * to be useful for REST in case a "GET request with body" is
     * required. */
 
    {NULL, 0, 0, 0, 0, 0}
    /* end of list */
};
 
 
/* All method names */
static char *all_methods = NULL; /* Built by mg_init_library */
 
 
static const struct mg_http_method_info *
get_http_method_info(const char *method)
{
    /* Check if the method is known to the server. The list of all known
     * HTTP methods can be found here at
     * http://www.iana.org/assignments/http-methods/http-methods.xhtml
     */
    const struct mg_http_method_info *m = http_methods;
 
    while (m->name) {
        if (!strcmp(m->name, method)) {
            return m;
        }
        m++;
    }
    return NULL;
}
 
 
static int
is_valid_http_method(const char *method)
{
    return (get_http_method_info(method) != NULL);
}
 
 
/* Parse HTTP request, fill in mg_request_info structure.
 * This function modifies the buffer by NUL-terminating
 * HTTP request components, header names and header values.
 * Parameters:
 *   buf (in/out): pointer to the HTTP header to parse and split
 *   len (in): length of HTTP header buffer
 *   re (out): parsed header as mg_request_info
 * buf and ri must be valid pointers (not NULL), len>0.
 * Returns <0 on error. */
static int
parse_http_request(char *buf, int len, struct mg_request_info *ri)
{
    int request_length;
    int init_skip = 0;
 
    /* Reset attributes. DO NOT TOUCH is_ssl, remote_addr,
     * remote_port */
    ri->remote_user = ri->request_method = ri->request_uri = ri->http_version =
        NULL;
    ri->num_headers = 0;
 
    /* RFC says that all initial whitespaces should be ignored */
    /* This included all leading \r and \n (isspace) */
    /* See table: http://www.cplusplus.com/reference/cctype/ */
    while ((len > 0) && isspace((unsigned char)*buf)) {
        buf++;
        len--;
        init_skip++;
    }
 
    if (len == 0) {
        /* Incomplete request */
        return 0;
    }
 
    /* Control characters are not allowed, including zero */
    if (iscntrl((unsigned char)*buf)) {
        return -1;
    }
 
    /* Find end of HTTP header */
    request_length = get_http_header_len(buf, len);
    if (request_length <= 0) {
        return request_length;
    }
    buf[request_length - 1] = '\0';
 
    if ((*buf == 0) || (*buf == '\r') || (*buf == '\n')) {
        return -1;
    }
 
    /* The first word has to be the HTTP method */
    ri->request_method = buf;
 
    if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
        return -1;
    }
 
    /* The second word is the URI */
    ri->request_uri = buf;
 
    if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
        return -1;
    }
 
    /* Next would be the HTTP version */
    ri->http_version = buf;
 
    if (skip_to_end_of_word_and_terminate(&buf, 1) <= 0) {
        return -1;
    }
 
    /* Check for a valid HTTP version key */
    if (strncmp(ri->http_version, "HTTP/", 5) != 0) {
        /* Invalid request */
        return -1;
    }
    ri->http_version += 5;
 
    /* Check for a valid http method */
    if (!is_valid_http_method(ri->request_method)) {
        return -1;
    }
 
    /* Parse all HTTP headers */
    ri->num_headers = parse_http_headers(&buf, ri->http_headers);
    if (ri->num_headers < 0) {
        /* Error while parsing headers */
        return -1;
    }
 
    return request_length + init_skip;
}
 
 
static int
parse_http_response(char *buf, int len, struct mg_response_info *ri)
{
    int response_length;
    int init_skip = 0;
    char *tmp, *tmp2;
    long l;
 
    /* Initialize elements. */
    ri->http_version = ri->status_text = NULL;
    ri->num_headers = ri->status_code = 0;
 
    /* RFC says that all initial whitespaces should be ignored */
    /* This included all leading \r and \n (isspace) */
    /* See table: http://www.cplusplus.com/reference/cctype/ */
    while ((len > 0) && isspace((unsigned char)*buf)) {
        buf++;
        len--;
        init_skip++;
    }
 
    if (len == 0) {
        /* Incomplete request */
        return 0;
    }
 
    /* Control characters are not allowed, including zero */
    if (iscntrl((unsigned char)*buf)) {
        return -1;
    }
 
    /* Find end of HTTP header */
    response_length = get_http_header_len(buf, len);
    if (response_length <= 0) {
        return response_length;
    }
    buf[response_length - 1] = '\0';
 
    if ((*buf == 0) || (*buf == '\r') || (*buf == '\n')) {
        return -1;
    }
 
    /* The first word is the HTTP version */
    /* Check for a valid HTTP version key */
    if (strncmp(buf, "HTTP/", 5) != 0) {
        /* Invalid request */
        return -1;
    }
    buf += 5;
    if (!isgraph((unsigned char)buf[0])) {
        /* Invalid request */
        return -1;
    }
    ri->http_version = buf;
 
    if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
        return -1;
    }
 
    /* The second word is the status as a number */
    tmp = buf;
 
    if (skip_to_end_of_word_and_terminate(&buf, 0) <= 0) {
        return -1;
    }
 
    l = strtol(tmp, &tmp2, 10);
    if ((l < 100) || (l >= 1000) || ((tmp2 - tmp) != 3) || (*tmp2 != 0)) {
        /* Everything else but a 3 digit code is invalid */
        return -1;
    }
    ri->status_code = (int)l;
 
    /* The rest of the line is the status text */
    ri->status_text = buf;
 
    /* Find end of status text */
    /* isgraph or isspace = isprint */
    while (isprint((unsigned char)*buf)) {
        buf++;
    }
    if ((*buf != '\r') && (*buf != '\n')) {
        return -1;
    }
    /* Terminate string and forward buf to next line */
    do {
        *buf = 0;
        buf++;
    } while (isspace((unsigned char)*buf));
 
    /* Parse all HTTP headers */
    ri->num_headers = parse_http_headers(&buf, ri->http_headers);
    if (ri->num_headers < 0) {
        /* Error while parsing headers */
        return -1;
    }
 
    return response_length + init_skip;
}
 
 
/* Keep reading the input (either opened file descriptor fd, or socket sock,
 * or SSL descriptor ssl) into buffer buf, until \r\n\r\n appears in the
 * buffer (which marks the end of HTTP request). Buffer buf may already
 * have some data. The length of the data is stored in nread.
 * Upon every read operation, increase nread by the number of bytes read. */
static int
read_message(FILE *fp,
             struct mg_connection *conn,
             char *buf,
             int bufsiz,
             int *nread)
{
    int request_len, n = 0;
    struct timespec last_action_time;
    double request_timeout;
 
    if (!conn) {
        return 0;
    }
 
    memset(&last_action_time, 0, sizeof(last_action_time));
 
    if (conn->dom_ctx->config[REQUEST_TIMEOUT]) {
        /* value of request_timeout is in seconds, config in milliseconds */
        request_timeout =
            strtod(conn->dom_ctx->config[REQUEST_TIMEOUT], NULL) / 1000.0;
    } else {
        request_timeout =
            strtod(config_options[REQUEST_TIMEOUT].default_value, NULL)
            / 1000.0;
    }
    if (conn->handled_requests > 0) {
        if (conn->dom_ctx->config[KEEP_ALIVE_TIMEOUT]) {
            request_timeout =
                strtod(conn->dom_ctx->config[KEEP_ALIVE_TIMEOUT], NULL)
                / 1000.0;
        }
    }
 
    request_len = get_http_header_len(buf, *nread);
 
    while (request_len == 0) {
        /* Full request not yet received */
        if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
            /* Server is to be stopped. */
            return -1;
        }
 
        if (*nread >= bufsiz) {
            /* Request too long */
            return -2;
        }
 
        n = pull_inner(
            fp, conn, buf + *nread, bufsiz - *nread, request_timeout);
        if (n == -2) {
            /* Receive error */
            return -1;
        }
 
        /* update clock after every read request */
        clock_gettime(CLOCK_MONOTONIC, &last_action_time);
 
        if (n > 0) {
            *nread += n;
            request_len = get_http_header_len(buf, *nread);
        }
 
        if ((request_len == 0) && (request_timeout >= 0)) {
            if (mg_difftimespec(&last_action_time, &(conn->req_time))
                > request_timeout) {
                /* Timeout */
                return -1;
            }
        }
    }
 
    return request_len;
}
 
 
#if !defined(NO_CGI) || !defined(NO_FILES)
static int
forward_body_data(struct mg_connection *conn, FILE *fp, SOCKET sock, SSL *ssl)
{
    const char *expect;
    char buf[MG_BUF_LEN];
    int success = 0;
 
    if (!conn) {
        return 0;
    }
 
    expect = mg_get_header(conn, "Expect");
    DEBUG_ASSERT(fp != NULL);
    if (!fp) {
        mg_send_http_error(conn, 500, "%s", "Error: NULL File");
        return 0;
    }
 
    if ((expect != NULL) && (mg_strcasecmp(expect, "100-continue") != 0)) {
        /* Client sent an "Expect: xyz" header and xyz is not 100-continue.
         */
        mg_send_http_error(conn, 417, "Error: Can not fulfill expectation");
    } else {
        if (expect != NULL) {
            (void)mg_printf(conn, "%s", "HTTP/1.1 100 Continue\r\n\r\n");
            conn->status_code = 100;
        } else {
            conn->status_code = 200;
        }
 
        DEBUG_ASSERT(conn->consumed_content == 0);
 
        if (conn->consumed_content != 0) {
            mg_send_http_error(conn, 500, "%s", "Error: Size mismatch");
            return 0;
        }
 
        for (;;) {
            int nread = mg_read(conn, buf, sizeof(buf));
            if (nread <= 0) {
                success = (nread == 0);
                break;
            }
            if (push_all(conn->phys_ctx, fp, sock, ssl, buf, nread) != nread) {
                break;
            }
        }
 
        /* Each error code path in this function must send an error */
        if (!success) {
            /* NOTE: Maybe some data has already been sent. */
            /* TODO (low): If some data has been sent, a correct error
             * reply can no longer be sent, so just close the connection */
            mg_send_http_error(conn, 500, "%s", "");
        }
    }
 
    return success;
}
#endif
 
 
#if defined(USE_TIMERS)
 
#define TIMER_API static
#include "timer.inl"
 
#endif /* USE_TIMERS */
 
 
#if !defined(NO_CGI)
/* This structure helps to create an environment for the spawned CGI
 * program.
 * Environment is an array of "VARIABLE=VALUE\0" ASCII strings,
 * last element must be NULL.
 * However, on Windows there is a requirement that all these
 * VARIABLE=VALUE\0
 * strings must reside in a contiguous buffer. The end of the buffer is
 * marked by two '\0' characters.
 * We satisfy both worlds: we create an envp array (which is vars), all
 * entries are actually pointers inside buf. */
struct cgi_environment {
    struct mg_connection *conn;
    /* Data block */
    char *buf;      /* Environment buffer */
    size_t buflen;  /* Space available in buf */
    size_t bufused; /* Space taken in buf */
    /* Index block */
    char **var;     /* char **envp */
    size_t varlen;  /* Number of variables available in var */
    size_t varused; /* Number of variables stored in var */
};
 
 
static void addenv(struct cgi_environment *env,
                   PRINTF_FORMAT_STRING(const char *fmt),
                   ...) PRINTF_ARGS(2, 3);
 
/* Append VARIABLE=VALUE\0 string to the buffer, and add a respective
 * pointer into the vars array. Assumes env != NULL and fmt != NULL. */
static void
addenv(struct cgi_environment *env, const char *fmt, ...)
{
    size_t i, n, space;
    int truncated = 0;
    char *added;
    va_list ap;
 
    if ((env->varlen - env->varused) < 2) {
        mg_cry_internal(env->conn,
                        "%s: Cannot register CGI variable [%s]",
                        __func__,
                        fmt);
        return;
    }
 
    /* Calculate how much space is left in the buffer */
    space = (env->buflen - env->bufused);
 
    do {
        /* Space for "\0\0" is always needed. */
        if (space <= 2) {
            /* Allocate new buffer */
            n = env->buflen + CGI_ENVIRONMENT_SIZE;
            added = (char *)mg_realloc_ctx(env->buf, n, env->conn->phys_ctx);
            if (!added) {
                /* Out of memory */
                mg_cry_internal(
                    env->conn,
                    "%s: Cannot allocate memory for CGI variable [%s]",
                    __func__,
                    fmt);
                return;
            }
            /* Retarget pointers */
            env->buf = added;
            env->buflen = n;
            for (i = 0, n = 0; i < env->varused; i++) {
                env->var[i] = added + n;
                n += strlen(added + n) + 1;
            }
            space = (env->buflen - env->bufused);
        }
 
        /* Make a pointer to the free space int the buffer */
        added = env->buf + env->bufused;
 
        /* Copy VARIABLE=VALUE\0 string into the free space */
        va_start(ap, fmt);
        mg_vsnprintf(env->conn, &truncated, added, space - 1, fmt, ap);
        va_end(ap);
 
        /* Do not add truncated strings to the environment */
        if (truncated) {
            /* Reallocate the buffer */
            space = 0;
        }
    } while (truncated);
 
    /* Calculate number of bytes added to the environment */
    n = strlen(added) + 1;
    env->bufused += n;
 
    /* Append a pointer to the added string into the envp array */
    env->var[env->varused] = added;
    env->varused++;
}
 
/* Return 0 on success, non-zero if an error occurs. */
 
static int
prepare_cgi_environment(struct mg_connection *conn,
                        const char *prog,
                        struct cgi_environment *env,
                        int cgi_config_idx)
{
    const char *s;
    struct vec var_vec;
    char *p, src_addr[IP_ADDR_STR_LEN], http_var_name[128];
    int i, truncated, uri_len;
 
    if ((conn == NULL) || (prog == NULL) || (env == NULL)) {
        return -1;
    }
 
    env->conn = conn;
    env->buflen = CGI_ENVIRONMENT_SIZE;
    env->bufused = 0;
    env->buf = (char *)mg_malloc_ctx(env->buflen, conn->phys_ctx);
    if (env->buf == NULL) {
        mg_cry_internal(conn,
                        "%s: Not enough memory for environmental buffer",
                        __func__);
        return -1;
    }
    env->varlen = MAX_CGI_ENVIR_VARS;
    env->varused = 0;
    env->var =
        (char **)mg_malloc_ctx(env->varlen * sizeof(char *), conn->phys_ctx);
    if (env->var == NULL) {
        mg_cry_internal(conn,
                        "%s: Not enough memory for environmental variables",
                        __func__);
        mg_free(env->buf);
        return -1;
    }
 
    addenv(env, "SERVER_NAME=%s", conn->dom_ctx->config[AUTHENTICATION_DOMAIN]);
    addenv(env, "SERVER_ROOT=%s", conn->dom_ctx->config[DOCUMENT_ROOT]);
    addenv(env, "DOCUMENT_ROOT=%s", conn->dom_ctx->config[DOCUMENT_ROOT]);
    addenv(env, "SERVER_SOFTWARE=CivetWeb/%s", mg_version());
 
    /* Prepare the environment block */
    addenv(env, "%s", "GATEWAY_INTERFACE=CGI/1.1");
    addenv(env, "%s", "SERVER_PROTOCOL=HTTP/1.1");
    addenv(env, "%s", "REDIRECT_STATUS=200"); /* For PHP */
 
    addenv(env, "SERVER_PORT=%d", conn->request_info.server_port);
 
    sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
    addenv(env, "REMOTE_ADDR=%s", src_addr);
 
    addenv(env, "REQUEST_METHOD=%s", conn->request_info.request_method);
    addenv(env, "REMOTE_PORT=%d", conn->request_info.remote_port);
 
    addenv(env, "REQUEST_URI=%s", conn->request_info.request_uri);
    addenv(env, "LOCAL_URI=%s", conn->request_info.local_uri);
    addenv(env, "LOCAL_URI_RAW=%s", conn->request_info.local_uri_raw);
 
    /* SCRIPT_NAME */
    uri_len = (int)strlen(conn->request_info.local_uri);
    if (conn->path_info == NULL) {
        if (conn->request_info.local_uri[uri_len - 1] != '/') {
            /* URI: /path_to_script/script.cgi */
            addenv(env, "SCRIPT_NAME=%s", conn->request_info.local_uri);
        } else {
            /* URI: /path_to_script/ ... using index.cgi */
            const char *index_file = strrchr(prog, '/');
            if (index_file) {
                addenv(env,
                       "SCRIPT_NAME=%s%s",
                       conn->request_info.local_uri,
                       index_file + 1);
            }
        }
    } else {
        /* URI: /path_to_script/script.cgi/path_info */
        addenv(env,
               "SCRIPT_NAME=%.*s",
               uri_len - (int)strlen(conn->path_info),
               conn->request_info.local_uri);
    }
 
    addenv(env, "SCRIPT_FILENAME=%s", prog);
    if (conn->path_info == NULL) {
        addenv(env, "PATH_TRANSLATED=%s", conn->dom_ctx->config[DOCUMENT_ROOT]);
    } else {
        addenv(env,
               "PATH_TRANSLATED=%s%s",
               conn->dom_ctx->config[DOCUMENT_ROOT],
               conn->path_info);
    }
 
    addenv(env, "HTTPS=%s", (conn->ssl == NULL) ? "off" : "on");
 
    if ((s = mg_get_header(conn, "Content-Type")) != NULL) {
        addenv(env, "CONTENT_TYPE=%s", s);
    }
    if (conn->request_info.query_string != NULL) {
        addenv(env, "QUERY_STRING=%s", conn->request_info.query_string);
    }
    if ((s = mg_get_header(conn, "Content-Length")) != NULL) {
        addenv(env, "CONTENT_LENGTH=%s", s);
    }
    if ((s = getenv("PATH")) != NULL) {
        addenv(env, "PATH=%s", s);
    }
    if (conn->path_info != NULL) {
        addenv(env, "PATH_INFO=%s", conn->path_info);
    }
 
    if (conn->status_code > 0) {
        /* CGI error handler should show the status code */
        addenv(env, "STATUS=%d", conn->status_code);
    }
 
#if defined(_WIN32)
    if ((s = getenv("COMSPEC")) != NULL) {
        addenv(env, "COMSPEC=%s", s);
    }
    if ((s = getenv("SYSTEMROOT")) != NULL) {
        addenv(env, "SYSTEMROOT=%s", s);
    }
    if ((s = getenv("SystemDrive")) != NULL) {
        addenv(env, "SystemDrive=%s", s);
    }
    if ((s = getenv("ProgramFiles")) != NULL) {
        addenv(env, "ProgramFiles=%s", s);
    }
    if ((s = getenv("ProgramFiles(x86)")) != NULL) {
        addenv(env, "ProgramFiles(x86)=%s", s);
    }
#else
    if ((s = getenv("LD_LIBRARY_PATH")) != NULL) {
        addenv(env, "LD_LIBRARY_PATH=%s", s);
    }
#endif /* _WIN32 */
 
    if ((s = getenv("PERLLIB")) != NULL) {
        addenv(env, "PERLLIB=%s", s);
    }
 
    if (conn->request_info.remote_user != NULL) {
        addenv(env, "REMOTE_USER=%s", conn->request_info.remote_user);
        addenv(env, "%s", "AUTH_TYPE=Digest");
    }
 
    /* Add all headers as HTTP_* variables */
    for (i = 0; i < conn->request_info.num_headers; i++) {
 
        (void)mg_snprintf(conn,
                          &truncated,
                          http_var_name,
                          sizeof(http_var_name),
                          "HTTP_%s",
                          conn->request_info.http_headers[i].name);
 
        if (truncated) {
            mg_cry_internal(conn,
                            "%s: HTTP header variable too long [%s]",
                            __func__,
                            conn->request_info.http_headers[i].name);
            continue;
        }
 
        /* Convert variable name into uppercase, and change - to _ */
        for (p = http_var_name; *p != '\0'; p++) {
            if (*p == '-') {
                *p = '_';
            }
            *p = (char)toupper((unsigned char)*p);
        }
 
        addenv(env,
               "%s=%s",
               http_var_name,
               conn->request_info.http_headers[i].value);
    }
 
    /* Add user-specified variables */
    s = conn->dom_ctx->config[CGI_ENVIRONMENT + cgi_config_idx];
    while ((s = next_option(s, &var_vec, NULL)) != NULL) {
        addenv(env, "%.*s", (int)var_vec.len, var_vec.ptr);
    }
 
    env->var[env->varused] = NULL;
    env->buf[env->bufused] = '\0';
 
    return 0;
}
 
 
/* Data for CGI process control: PID and number of references */
struct process_control_data {
    pid_t pid;
    ptrdiff_t references;
};
 
static int
abort_cgi_process(void *data)
{
    /* Waitpid checks for child status and won't work for a pid that does
     * not identify a child of the current process. Thus, if the pid is
     * reused, we will not affect a different process. */
    struct process_control_data *proc = (struct process_control_data *)data;
    int status = 0;
    ptrdiff_t refs;
    pid_t ret_pid;
 
    ret_pid = waitpid(proc->pid, &status, WNOHANG);
    if ((ret_pid != (pid_t)-1) && (status == 0)) {
        /* Stop child process */
        DEBUG_TRACE("CGI timer: Stop child process %d\n", proc->pid);
        kill(proc->pid, SIGABRT);
 
        /* Wait until process is terminated (don't leave zombies) */
        while (waitpid(proc->pid, &status, 0) != (pid_t)-1) /* nop */
            ;
    } else {
        DEBUG_TRACE("CGI timer: Child process %d already stopped\n", proc->pid);
    }
    /* Dec reference counter */
    refs = mg_atomic_dec(&proc->references);
    if (refs == 0) {
        /* no more references - free data */
        mg_free(data);
    }
 
    return 0;
}
 
 
/* Local (static) function assumes all arguments are valid. */
static void
handle_cgi_request(struct mg_connection *conn,
                   const char *prog,
                   int cgi_config_idx)
{
    char *buf;
    size_t buflen;
    int headers_len, data_len, i, truncated;
    int fdin[2] = {-1, -1}, fdout[2] = {-1, -1}, fderr[2] = {-1, -1};
    const char *status, *status_text;
    char *pbuf, dir[UTF8_PATH_MAX], *p;
    struct mg_request_info ri;
    struct cgi_environment blk;
    FILE *in = NULL, *out = NULL, *err = NULL;
    struct mg_file fout = STRUCT_FILE_INITIALIZER;
    pid_t pid = (pid_t)-1;
    struct process_control_data *proc = NULL;
    char *cfg_buffering = conn->dom_ctx->config[CGI_BUFFERING + cgi_config_idx];
    int no_buffering = 0;
 
#if defined(USE_TIMERS)
    double cgi_timeout;
    if (conn->dom_ctx->config[CGI_TIMEOUT + cgi_config_idx]) {
        /* Get timeout in seconds */
        cgi_timeout =
            atof(conn->dom_ctx->config[CGI_TIMEOUT + cgi_config_idx]) * 0.001;
    } else {
        cgi_timeout =
            atof(config_options[REQUEST_TIMEOUT].default_value) * 0.001;
    }
#endif
    if (cfg_buffering != NULL) {
        if (!mg_strcasecmp(cfg_buffering, "no")) {
            no_buffering = 1;
        }
    }
 
    buf = NULL;
    buflen = conn->phys_ctx->max_request_size;
    i = prepare_cgi_environment(conn, prog, &blk, cgi_config_idx);
    if (i != 0) {
        blk.buf = NULL;
        blk.var = NULL;
        goto done;
    }
 
    /* CGI must be executed in its own directory. 'dir' must point to the
     * directory containing executable program, 'p' must point to the
     * executable program name relative to 'dir'. */
    (void)mg_snprintf(conn, &truncated, dir, sizeof(dir), "%s", prog);
 
    if (truncated) {
        mg_cry_internal(conn, "Error: CGI program \"%s\": Path too long", prog);
        mg_send_http_error(conn, 500, "Error: %s", "CGI path too long");
        goto done;
    }
 
    if ((p = strrchr(dir, '/')) != NULL) {
        *p++ = '\0';
    } else {
        dir[0] = '.';
        dir[1] = '\0';
        p = (char *)prog;
    }
 
    if ((pipe(fdin) != 0) || (pipe(fdout) != 0) || (pipe(fderr) != 0)) {
        status = strerror(ERRNO);
        mg_cry_internal(
            conn,
            "Error: CGI program \"%s\": Can not create CGI pipes: %s",
            prog,
            status);
        mg_send_http_error(conn,
                           500,
                           "Error: Cannot create CGI pipe: %s",
                           status);
        goto done;
    }
 
    proc = (struct process_control_data *)
        mg_malloc_ctx(sizeof(struct process_control_data), conn->phys_ctx);
    if (proc == NULL) {
        mg_cry_internal(conn, "Error: CGI program \"%s\": Out or memory", prog);
        mg_send_http_error(conn, 500, "Error: Out of memory [%s]", prog);
        goto done;
    }
 
    DEBUG_TRACE("CGI: spawn %s %s\n", dir, p);
    pid = spawn_process(
        conn, p, blk.buf, blk.var, fdin, fdout, fderr, dir, cgi_config_idx);
 
    if (pid == (pid_t)-1) {
        status = strerror(ERRNO);
        mg_cry_internal(
            conn,
            "Error: CGI program \"%s\": Can not spawn CGI process: %s",
            prog,
            status);
        mg_send_http_error(conn, 500, "Error: Cannot spawn CGI process");
        mg_free(proc);
        proc = NULL;
        goto done;
    }
 
    /* Store data in shared process_control_data */
    proc->pid = pid;
    proc->references = 1;
 
#if defined(USE_TIMERS)
    if (cgi_timeout > 0.0) {
        proc->references = 2;
 
        // Start a timer for CGI
        timer_add(conn->phys_ctx,
                  cgi_timeout /* in seconds */,
                  0.0,
                  1,
                  abort_cgi_process,
                  (void *)proc,
                  NULL);
    }
#endif
 
    /* Parent closes only one side of the pipes.
     * If we don't mark them as closed, close() attempt before
     * return from this function throws an exception on Windows.
     * Windows does not like when closed descriptor is closed again. */
    (void)close(fdin[0]);
    (void)close(fdout[1]);
    (void)close(fderr[1]);
    fdin[0] = fdout[1] = fderr[1] = -1;
 
    if (((in = fdopen(fdin[1], "wb")) == NULL)
        || ((out = fdopen(fdout[0], "rb")) == NULL)
        || ((err = fdopen(fderr[0], "rb")) == NULL)) {
        status = strerror(ERRNO);
        mg_cry_internal(conn,
                        "Error: CGI program \"%s\": Can not open fd: %s",
                        prog,
                        status);
        mg_send_http_error(conn,
                           500,
                           "Error: CGI can not open fd\nfdopen: %s",
                           status);
        goto done;
    }
 
    setbuf(in, NULL);
    setbuf(out, NULL);
    setbuf(err, NULL);
    fout.access.fp = out;
 
    if ((conn->content_len != 0) || (conn->is_chunked)) {
        DEBUG_TRACE("CGI: send body data (%" INT64_FMT ")\n",
                    conn->content_len);
 
        /* This is a POST/PUT request, or another request with body data. */
        if (!forward_body_data(conn, in, INVALID_SOCKET, NULL)) {
            /* Error sending the body data */
            mg_cry_internal(
                conn,
                "Error: CGI program \"%s\": Forward body data failed",
                prog);
            goto done;
        }
    }
 
    /* Close so child gets an EOF. */
    fclose(in);
    in = NULL;
    fdin[1] = -1;
 
    /* Now read CGI reply into a buffer. We need to set correct
     * status code, thus we need to see all HTTP headers first.
     * Do not send anything back to client, until we buffer in all
     * HTTP headers. */
    data_len = 0;
    buf = (char *)mg_malloc_ctx(buflen, conn->phys_ctx);
    if (buf == NULL) {
        mg_send_http_error(conn,
                           500,
                           "Error: Not enough memory for CGI buffer (%u bytes)",
                           (unsigned int)buflen);
        mg_cry_internal(
            conn,
            "Error: CGI program \"%s\": Not enough memory for buffer (%u "
            "bytes)",
            prog,
            (unsigned int)buflen);
        goto done;
    }
 
    DEBUG_TRACE("CGI: %s", "wait for response");
    headers_len = read_message(out, conn, buf, (int)buflen, &data_len);
    DEBUG_TRACE("CGI: response: %li", (signed long)headers_len);
 
    if (headers_len <= 0) {
 
        /* Could not parse the CGI response. Check if some error message on
         * stderr. */
        i = pull_all(err, conn, buf, (int)buflen);
        if (i > 0) {
            /* CGI program explicitly sent an error */
            /* Write the error message to the internal log */
            mg_cry_internal(conn,
                            "Error: CGI program \"%s\" sent error "
                            "message: [%.*s]",
                            prog,
                            i,
                            buf);
            /* Don't send the error message back to the client */
            mg_send_http_error(conn,
                               500,
                               "Error: CGI program \"%s\" failed.",
                               prog);
        } else {
            /* CGI program did not explicitly send an error, but a broken
             * respon header */
            mg_cry_internal(conn,
                            "Error: CGI program sent malformed or too big "
                            "(>%u bytes) HTTP headers: [%.*s]",
                            (unsigned)buflen,
                            data_len,
                            buf);
 
            mg_send_http_error(conn,
                               500,
                               "Error: CGI program sent malformed or too big "
                               "(>%u bytes) HTTP headers: [%.*s]",
                               (unsigned)buflen,
                               data_len,
                               buf);
        }
 
        /* in both cases, abort processing CGI */
        goto done;
    }
 
    pbuf = buf;
    buf[headers_len - 1] = '\0';
    ri.num_headers = parse_http_headers(&pbuf, ri.http_headers);
 
    /* Make up and send the status line */
    status_text = "OK";
    if ((status = get_header(ri.http_headers, ri.num_headers, "Status"))
        != NULL) {
        conn->status_code = atoi(status);
        status_text = status;
        while (isdigit((unsigned char)*status_text) || *status_text == ' ') {
            status_text++;
        }
    } else if (get_header(ri.http_headers, ri.num_headers, "Location")
               != NULL) {
        conn->status_code = 307;
    } else {
        conn->status_code = 200;
    }
 
    if (!should_keep_alive(conn)) {
        conn->must_close = 1;
    }
 
    DEBUG_TRACE("CGI: response %u %s", conn->status_code, status_text);
 
    (void)mg_printf(conn, "HTTP/1.1 %d %s\r\n", conn->status_code, status_text);
 
    /* Send headers */
    for (i = 0; i < ri.num_headers; i++) {
        DEBUG_TRACE("CGI header: %s: %s",
                    ri.http_headers[i].name,
                    ri.http_headers[i].value);
        mg_printf(conn,
                  "%s: %s\r\n",
                  ri.http_headers[i].name,
                  ri.http_headers[i].value);
    }
    mg_write(conn, "\r\n", 2);
 
    /* Send chunk of data that may have been read after the headers */
    mg_write(conn, buf + headers_len, (size_t)(data_len - headers_len));
 
    /* Read the rest of CGI output and send to the client */
    DEBUG_TRACE("CGI: %s", "forward all data");
    send_file_data(conn, &fout, 0, INT64_MAX, no_buffering); /* send CGI data */
    DEBUG_TRACE("CGI: %s", "all data sent");
 
done:
    mg_free(blk.var);
    mg_free(blk.buf);
 
    if (pid != (pid_t)-1) {
        abort_cgi_process((void *)proc);
    }
 
    if (fdin[0] != -1) {
        close(fdin[0]);
    }
    if (fdout[1] != -1) {
        close(fdout[1]);
    }
    if (fderr[1] != -1) {
        close(fderr[1]);
    }
 
    if (in != NULL) {
        fclose(in);
    } else if (fdin[1] != -1) {
        close(fdin[1]);
    }
 
    if (out != NULL) {
        fclose(out);
    } else if (fdout[0] != -1) {
        close(fdout[0]);
    }
 
    if (err != NULL) {
        fclose(err);
    } else if (fderr[0] != -1) {
        close(fderr[0]);
    }
 
    mg_free(buf);
}
#endif /* !NO_CGI */
 
 
#if !defined(NO_FILES)
static void
dav_mkcol(struct mg_connection *conn, const char *path)
{
    int rc, body_len;
    struct de de;
 
    if (conn == NULL) {
        return;
    }
 
    /* TODO (mid): Check the mg_send_http_error situations in this function
     */
 
    memset(&de.file, 0, sizeof(de.file));
    if (!mg_stat(conn, path, &de.file)) {
        mg_cry_internal(conn,
                        "%s: mg_stat(%s) failed: %s",
                        __func__,
                        path,
                        strerror(ERRNO));
    }
 
    if (de.file.last_modified) {
        /* TODO (mid): This check does not seem to make any sense ! */
        /* TODO (mid): Add a webdav unit test first, before changing
         * anything here. */
        mg_send_http_error(
            conn, 405, "Error: mkcol(%s): %s", path, strerror(ERRNO));
        return;
    }
 
    body_len = conn->data_len - conn->request_len;
    if (body_len > 0) {
        mg_send_http_error(
            conn, 415, "Error: mkcol(%s): %s", path, strerror(ERRNO));
        return;
    }
 
    rc = mg_mkdir(conn, path, 0755);
    DEBUG_TRACE("mkdir %s: %i", path, rc);
    if (rc == 0) {
        /* Create 201 "Created" response */
        mg_response_header_start(conn, 201);
        send_static_cache_header(conn);
        send_additional_header(conn);
        mg_response_header_add(conn, "Content-Length", "0", -1);
 
        /* Send all headers - there is no body */
        mg_response_header_send(conn);
    } else {
        int http_status = 500;
        switch (errno) {
        case EEXIST:
            http_status = 405;
            break;
        case EACCES:
            http_status = 403;
            break;
        case ENOENT:
            http_status = 409;
            break;
        }
 
        mg_send_http_error(conn,
                           http_status,
                           "Error processing %s: %s",
                           path,
                           strerror(ERRNO));
    }
}
 
 
/* Forward decrlaration */
static int get_uri_type(const char *uri);
static const char *
get_rel_url_at_current_server(const char *uri,
                              const struct mg_connection *conn);
 
 
static void
dav_move_file(struct mg_connection *conn, const char *path, int do_copy)
{
    const char *overwrite_hdr;
    const char *destination_hdr;
    const char *root;
    int rc, dest_uri_type;
    int http_status = 400;
    int do_overwrite = 0;
    int destination_ok = 0;
    char dest_path[UTF8_PATH_MAX];
    struct mg_file_stat ignored;
 
    if (conn == NULL) {
        return;
    }
 
    root = conn->dom_ctx->config[DOCUMENT_ROOT];
    overwrite_hdr = mg_get_header(conn, "Overwrite");
    destination_hdr = mg_get_header(conn, "Destination");
    if ((overwrite_hdr != NULL) && (toupper(overwrite_hdr[0]) == 'T')) {
        do_overwrite = 1;
    }
 
    if ((destination_hdr == NULL) || (destination_hdr[0] == 0)) {
        mg_send_http_error(conn, 400, "%s", "Missing destination");
        return;
    }
 
    if (root != NULL) {
        char *local_dest = NULL;
        dest_uri_type = get_uri_type(destination_hdr);
        if (dest_uri_type == 2) {
            local_dest = mg_strdup_ctx(destination_hdr, conn->phys_ctx);
        } else if ((dest_uri_type == 3) || (dest_uri_type == 4)) {
            const char *h =
                get_rel_url_at_current_server(destination_hdr, conn);
            if (h) {
                size_t len = strlen(h);
                local_dest = mg_malloc_ctx(len + 1, conn->phys_ctx);
                mg_url_decode(h, (int)len, local_dest, (int)len + 1, 0);
            }
        }
        if (local_dest != NULL) {
            remove_dot_segments(local_dest);
            if (local_dest[0] == '/') {
                int trunc_check = 0;
                mg_snprintf(conn,
                            &trunc_check,
                            dest_path,
                            sizeof(dest_path),
                            "%s/%s",
                            root,
                            local_dest);
                if (trunc_check == 0) {
                    destination_ok = 1;
                }
            }
            mg_free(local_dest);
        }
    }
 
    if (!destination_ok) {
        mg_send_http_error(conn, 502, "%s", "Illegal destination");
        return;
    }
 
    /* Check now if this file exists */
    if (mg_stat(conn, dest_path, &ignored)) {
        /* File exists */
        if (do_overwrite) {
            /* Overwrite allowed: delete the file first */
            if (0 != remove(dest_path)) {
                /* No overwrite: return error */
                mg_send_http_error(conn,
                                   403,
                                   "Cannot overwrite file: %s",
                                   dest_path);
                return;
            }
        } else {
            /* No overwrite: return error */
            mg_send_http_error(conn,
                               412,
                               "Destination already exists: %s",
                               dest_path);
            return;
        }
    }
 
    /* Copy / Move / Rename operation. */
    DEBUG_TRACE("%s %s to %s", (do_copy ? "copy" : "move"), path, dest_path);
#if defined(_WIN32)
    {
        /* For Windows, we need to convert from UTF-8 to UTF-16 first. */
        wchar_t wSource[UTF16_PATH_MAX];
        wchar_t wDest[UTF16_PATH_MAX];
        BOOL ok;
 
        path_to_unicode(conn, path, wSource, ARRAY_SIZE(wSource));
        path_to_unicode(conn, dest_path, wDest, ARRAY_SIZE(wDest));
        if (do_copy) {
            ok = CopyFileW(wSource, wDest, do_overwrite ? FALSE : TRUE);
        } else {
            ok = MoveFileExW(wSource,
                             wDest,
                             do_overwrite ? MOVEFILE_REPLACE_EXISTING : 0);
        }
        if (ok) {
            rc = 0;
        } else {
            DWORD lastErr = GetLastError();
            if (lastErr == ERROR_ALREADY_EXISTS) {
                mg_send_http_error(conn,
                                   412,
                                   "Destination already exists: %s",
                                   dest_path);
                return;
            }
            rc = -1;
            http_status = 400;
        }
    }
 
#else
    {
        /* Linux uses already UTF-8, we don't need to convert file names. */
 
        if (do_copy) {
            /* TODO: COPY for Linux. */
            mg_send_http_error(conn, 403, "%s", "COPY forbidden");
            return;
        }
 
        rc = rename(path, dest_path);
        if (rc) {
            switch (errno) {
            case EEXIST:
                http_status = 412;
                break;
            case EACCES:
                http_status = 403;
                break;
            case ENOENT:
                http_status = 409;
                break;
            }
        }
    }
#endif
 
    if (rc == 0) {
        /* Create 204 "No Content" response */
        mg_response_header_start(conn, 204);
        mg_response_header_add(conn, "Content-Length", "0", -1);
 
        /* Send all headers - there is no body */
        mg_response_header_send(conn);
    } else {
        mg_send_http_error(conn, http_status, "Operation failed");
    }
}
 
 
static void
put_file(struct mg_connection *conn, const char *path)
{
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    const char *range;
    int64_t r1, r2;
    int rc;
 
    if (conn == NULL) {
        return;
    }
 
    DEBUG_TRACE("store %s", path);
 
    if (mg_stat(conn, path, &file.stat)) {
        /* File already exists */
        conn->status_code = 200;
 
        if (file.stat.is_directory) {
            /* This is an already existing directory,
             * so there is nothing to do for the server. */
            rc = 0;
 
        } else {
            /* File exists and is not a directory. */
            /* Can it be replaced? */
 
            /* Check if the server may write this file */
            if (access(path, W_OK) == 0) {
                /* Access granted */
                rc = 1;
            } else {
                mg_send_http_error(
                    conn,
                    403,
                    "Error: Put not possible\nReplacing %s is not allowed",
                    path);
                return;
            }
        }
    } else {
        /* File should be created */
        conn->status_code = 201;
        rc = put_dir(conn, path);
    }
 
    if (rc == 0) {
        /* put_dir returns 0 if path is a directory */
 
        /* Create response */
        mg_response_header_start(conn, conn->status_code);
        send_no_cache_header(conn);
        send_additional_header(conn);
        mg_response_header_add(conn, "Content-Length", "0", -1);
 
        /* Send all headers - there is no body */
        mg_response_header_send(conn);
 
        /* Request to create a directory has been fulfilled successfully.
         * No need to put a file. */
        return;
    }
 
    if (rc == -1) {
        /* put_dir returns -1 if the path is too long */
        mg_send_http_error(conn,
                           414,
                           "Error: Path too long\nput_dir(%s): %s",
                           path,
                           strerror(ERRNO));
        return;
    }
 
    if (rc == -2) {
        /* put_dir returns -2 if the directory can not be created */
        mg_send_http_error(conn,
                           500,
                           "Error: Can not create directory\nput_dir(%s): %s",
                           path,
                           strerror(ERRNO));
        return;
    }
 
    /* A file should be created or overwritten. */
    /* Currently CivetWeb does not need read+write access. */
    if (!mg_fopen(conn, path, MG_FOPEN_MODE_WRITE, &file)
        || file.access.fp == NULL) {
        (void)mg_fclose(&file.access);
        mg_send_http_error(conn,
                           500,
                           "Error: Can not create file\nfopen(%s): %s",
                           path,
                           strerror(ERRNO));
        return;
    }
 
    fclose_on_exec(&file.access, conn);
    range = mg_get_header(conn, "Content-Range");
    r1 = r2 = 0;
    if ((range != NULL) && parse_range_header(range, &r1, &r2) > 0) {
        conn->status_code = 206; /* Partial content */
        if (0 != fseeko(file.access.fp, r1, SEEK_SET)) {
            mg_send_http_error(conn,
                               500,
                               "Error: Internal error processing file %s",
                               path);
            return;
        }
    }
 
    if (!forward_body_data(conn, file.access.fp, INVALID_SOCKET, NULL)) {
        /* forward_body_data failed.
         * The error code has already been sent to the client,
         * and conn->status_code is already set. */
        (void)mg_fclose(&file.access);
        return;
    }
 
    if (mg_fclose(&file.access) != 0) {
        /* fclose failed. This might have different reasons, but a likely
         * one is "no space on disk", http 507. */
        conn->status_code = 507;
    }
 
    /* Create response (status_code has been set before) */
    mg_response_header_start(conn, conn->status_code);
    send_no_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn, "Content-Length", "0", -1);
 
    /* Send all headers - there is no body */
    mg_response_header_send(conn);
}
 
 
static void
delete_file(struct mg_connection *conn, const char *path)
{
    struct de de;
    memset(&de.file, 0, sizeof(de.file));
    if (!mg_stat(conn, path, &de.file)) {
        /* mg_stat returns 0 if the file does not exist */
        mg_send_http_error(conn,
                           404,
                           "Error: Cannot delete file\nFile %s not found",
                           path);
        return;
    }
 
    DEBUG_TRACE("delete %s", path);
 
    if (de.file.is_directory) {
        if (remove_directory(conn, path)) {
            /* Delete is successful: Return 204 without content. */
            mg_send_http_error(conn, 204, "%s", "");
        } else {
            /* Delete is not successful: Return 500 (Server error). */
            mg_send_http_error(conn, 500, "Error: Could not delete %s", path);
        }
        return;
    }
 
    /* This is an existing file (not a directory).
     * Check if write permission is granted. */
    if (access(path, W_OK) != 0) {
        /* File is read only */
        mg_send_http_error(
            conn,
            403,
            "Error: Delete not possible\nDeleting %s is not allowed",
            path);
        return;
    }
 
    /* Try to delete it. */
    if (mg_remove(conn, path) == 0) {
        /* Delete was successful: Return 204 without content. */
        mg_response_header_start(conn, 204);
        send_no_cache_header(conn);
        send_additional_header(conn);
        mg_response_header_add(conn, "Content-Length", "0", -1);
        mg_response_header_send(conn);
 
    } else {
        /* Delete not successful (file locked). */
        mg_send_http_error(conn,
                           423,
                           "Error: Cannot delete file\nremove(%s): %s",
                           path,
                           strerror(ERRNO));
    }
}
#endif /* !NO_FILES */
 
 
#if !defined(NO_FILESYSTEMS)
static void
send_ssi_file(struct mg_connection *, const char *, struct mg_file *, int);
 
 
static void
do_ssi_include(struct mg_connection *conn,
               const char *ssi,
               char *tag,
               int include_level)
{
    char file_name[MG_BUF_LEN], path[512], *p;
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    size_t len;
    int truncated = 0;
 
    if (conn == NULL) {
        return;
    }
 
    /* sscanf() is safe here, since send_ssi_file() also uses buffer
     * of size MG_BUF_LEN to get the tag. So strlen(tag) is
     * always < MG_BUF_LEN. */
    if (sscanf(tag, " virtual=\"%511[^\"]\"", file_name) == 1) {
        /* File name is relative to the webserver root */
        file_name[511] = 0;
        (void)mg_snprintf(conn,
                          &truncated,
                          path,
                          sizeof(path),
                          "%s/%s",
                          conn->dom_ctx->config[DOCUMENT_ROOT],
                          file_name);
 
    } else if (sscanf(tag, " abspath=\"%511[^\"]\"", file_name) == 1) {
        /* File name is relative to the webserver working directory
         * or it is absolute system path */
        file_name[511] = 0;
        (void)
            mg_snprintf(conn, &truncated, path, sizeof(path), "%s", file_name);
 
    } else if ((sscanf(tag, " file=\"%511[^\"]\"", file_name) == 1)
               || (sscanf(tag, " \"%511[^\"]\"", file_name) == 1)) {
        /* File name is relative to the current document */
        file_name[511] = 0;
        (void)mg_snprintf(conn, &truncated, path, sizeof(path), "%s", ssi);
 
        if (!truncated) {
            if ((p = strrchr(path, '/')) != NULL) {
                p[1] = '\0';
            }
            len = strlen(path);
            (void)mg_snprintf(conn,
                              &truncated,
                              path + len,
                              sizeof(path) - len,
                              "%s",
                              file_name);
        }
 
    } else {
        mg_cry_internal(conn, "Bad SSI #include: [%s]", tag);
        return;
    }
 
    if (truncated) {
        mg_cry_internal(conn, "SSI #include path length overflow: [%s]", tag);
        return;
    }
 
    if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, &file)) {
        mg_cry_internal(conn,
                        "Cannot open SSI #include: [%s]: fopen(%s): %s",
                        tag,
                        path,
                        strerror(ERRNO));
    } else {
        fclose_on_exec(&file.access, conn);
        if (match_prefix_strlen(conn->dom_ctx->config[SSI_EXTENSIONS], path)
            > 0) {
            send_ssi_file(conn, path, &file, include_level + 1);
        } else {
            send_file_data(conn, &file, 0, INT64_MAX, 0); /* send static file */
        }
        (void)mg_fclose(&file.access); /* Ignore errors for readonly files */
    }
}
 
 
#if !defined(NO_POPEN)
static void
do_ssi_exec(struct mg_connection *conn, char *tag)
{
    char cmd[1024] = "";
    struct mg_file file = STRUCT_FILE_INITIALIZER;
 
    if (sscanf(tag, " \"%1023[^\"]\"", cmd) != 1) {
        mg_cry_internal(conn, "Bad SSI #exec: [%s]", tag);
    } else {
        cmd[1023] = 0;
        if ((file.access.fp = popen(cmd, "r")) == NULL) {
            mg_cry_internal(conn,
                            "Cannot SSI #exec: [%s]: %s",
                            cmd,
                            strerror(ERRNO));
        } else {
            send_file_data(conn, &file, 0, INT64_MAX, 0); /* send static file */
            pclose(file.access.fp);
        }
    }
}
#endif /* !NO_POPEN */
 
 
static int
mg_fgetc(struct mg_file *filep)
{
    if (filep == NULL) {
        return EOF;
    }
 
    if (filep->access.fp != NULL) {
        return fgetc(filep->access.fp);
    } else {
        return EOF;
    }
}
 
 
static void
send_ssi_file(struct mg_connection *conn,
              const char *path,
              struct mg_file *filep,
              int include_level)
{
    char buf[MG_BUF_LEN];
    int ch, len, in_tag, in_ssi_tag;
 
    if (include_level > 10) {
        mg_cry_internal(conn, "SSI #include level is too deep (%s)", path);
        return;
    }
 
    in_tag = in_ssi_tag = len = 0;
 
    /* Read file, byte by byte, and look for SSI include tags */
    while ((ch = mg_fgetc(filep)) != EOF) {
 
        if (in_tag) {
            /* We are in a tag, either SSI tag or html tag */
 
            if (ch == '>') {
                /* Tag is closing */
                buf[len++] = '>';
 
                if (in_ssi_tag) {
                    /* Handle SSI tag */
                    buf[len] = 0;
 
                    if ((len > 12) && !memcmp(buf + 5, "include", 7)) {
                        do_ssi_include(conn, path, buf + 12, include_level + 1);
#if !defined(NO_POPEN)
                    } else if ((len > 9) && !memcmp(buf + 5, "exec", 4)) {
                        do_ssi_exec(conn, buf + 9);
#endif /* !NO_POPEN */
                    } else {
                        mg_cry_internal(conn,
                                        "%s: unknown SSI "
                                        "command: \"%s\"",
                                        path,
                                        buf);
                    }
                    len = 0;
                    in_ssi_tag = in_tag = 0;
 
                } else {
                    /* Not an SSI tag */
                    /* Flush buffer */
                    (void)mg_write(conn, buf, (size_t)len);
                    len = 0;
                    in_tag = 0;
                }
 
            } else {
                /* Tag is still open */
                buf[len++] = (char)(ch & 0xff);
 
                if ((len == 5) && !memcmp(buf, "<!--#", 5)) {
                    /* All SSI tags start with <!--# */
                    in_ssi_tag = 1;
                }
 
                if ((len + 2) > (int)sizeof(buf)) {
                    /* Tag to long for buffer */
                    mg_cry_internal(conn, "%s: tag is too large", path);
                    return;
                }
            }
 
        } else {
 
            /* We are not in a tag yet. */
            if (ch == '<') {
                /* Tag is opening */
                in_tag = 1;
 
                if (len > 0) {
                    /* Flush current buffer.
                     * Buffer is filled with "len" bytes. */
                    (void)mg_write(conn, buf, (size_t)len);
                }
                /* Store the < */
                len = 1;
                buf[0] = '<';
 
            } else {
                /* No Tag */
                /* Add data to buffer */
                buf[len++] = (char)(ch & 0xff);
                /* Flush if buffer is full */
                if (len == (int)sizeof(buf)) {
                    mg_write(conn, buf, (size_t)len);
                    len = 0;
                }
            }
        }
    }
 
    /* Send the rest of buffered data */
    if (len > 0) {
        mg_write(conn, buf, (size_t)len);
    }
}
 
 
static void
handle_ssi_file_request(struct mg_connection *conn,
                        const char *path,
                        struct mg_file *filep)
{
    char date[64];
    time_t curtime = time(NULL);
 
    if ((conn == NULL) || (path == NULL) || (filep == NULL)) {
        return;
    }
 
    if (!mg_fopen(conn, path, MG_FOPEN_MODE_READ, filep)) {
        /* File exists (precondition for calling this function),
         * but can not be opened by the server. */
        mg_send_http_error(conn,
                           500,
                           "Error: Cannot read file\nfopen(%s): %s",
                           path,
                           strerror(ERRNO));
    } else {
        /* Set "must_close" for HTTP/1.x, since we do not know the
         * content length */
        conn->must_close = 1;
        gmt_time_string(date, sizeof(date), &curtime);
        fclose_on_exec(&filep->access, conn);
 
        /* 200 OK response */
        mg_response_header_start(conn, 200);
        send_no_cache_header(conn);
        send_additional_header(conn);
        send_cors_header(conn);
        mg_response_header_add(conn, "Content-Type", "text/html", -1);
        mg_response_header_send(conn);
 
        /* Header sent, now send body */
        send_ssi_file(conn, path, filep, 0);
        (void)mg_fclose(&filep->access); /* Ignore errors for readonly files */
    }
}
#endif /* NO_FILESYSTEMS */
 
 
#if !defined(NO_FILES)
static void
send_options(struct mg_connection *conn)
{
    if (!conn || !all_methods) {
        return;
    }
 
    /* We do not set a "Cache-Control" header here, but leave the default.
     * Since browsers do not send an OPTIONS request, we can not test the
     * effect anyway. */
 
    mg_response_header_start(conn, 200);
    mg_response_header_add(conn, "Content-Type", "text/html", -1);
 
    if (conn->protocol_type == PROTOCOL_TYPE_HTTP1) {
        /* Use the same as before */
        mg_response_header_add(conn, "Allow", all_methods, -1);
        mg_response_header_add(conn, "DAV", "1", -1);
    } else {
        /* TODO: Check this later for HTTP/2 */
        mg_response_header_add(conn, "Allow", "GET, POST", -1);
    }
    send_additional_header(conn);
    mg_response_header_send(conn);
}
 
 
/* Writes PROPFIND properties for a collection element */
static int
print_props(struct mg_connection *conn,
            const char *uri,
            const char *name,
            struct mg_file_stat *filep)
{
    size_t i;
    char mtime[64];
    char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */
    char *link_concat;
    size_t link_concat_len;
 
    if ((conn == NULL) || (uri == NULL) || (name == NULL) || (filep == NULL)) {
        return 0;
    }
 
    link_concat_len = strlen(uri) + strlen(name) + 1;
    link_concat = mg_malloc_ctx(link_concat_len, conn->phys_ctx);
    if (!link_concat) {
        return 0;
    }
    strcpy(link_concat, uri);
    strcat(link_concat, name);
 
    /* Get full link used in request */
    mg_construct_local_link(
        conn, link_buf, sizeof(link_buf), NULL, 0, link_concat);
 
    /*
    OutputDebugStringA("print_props:\n  uri: ");
    OutputDebugStringA(uri);
    OutputDebugStringA("\n  name: ");
    OutputDebugStringA(name);
    OutputDebugStringA("\n  link: ");
    OutputDebugStringA(link_buf);
    OutputDebugStringA("\n");
    */
 
    gmt_time_string(mtime, sizeof(mtime), &filep->last_modified);
    mg_printf(conn,
              "<d:response>"
              "<d:href>%s</d:href>"
              "<d:propstat>"
              "<d:prop>"
              "<d:resourcetype>%s</d:resourcetype>"
              "<d:getcontentlength>%" INT64_FMT "</d:getcontentlength>"
              "<d:getlastmodified>%s</d:getlastmodified>"
              "<d:lockdiscovery>",
              link_buf,
              filep->is_directory ? "<d:collection/>" : "",
              filep->size,
              mtime);
 
    for (i = 0; i < NUM_WEBDAV_LOCKS; i++) {
        struct twebdav_lock *dav_lock = conn->phys_ctx->webdav_lock;
        if (!strcmp(dav_lock[i].path, link_buf)) {
            mg_printf(conn,
                      "<d:activelock>"
                      "<d:locktype><d:write/></d:locktype>"
                      "<d:lockscope><d:exclusive/></d:lockscope>"
                      "<d:depth>0</d:depth>"
                      "<d:owner>%s</d:owner>"
                      "<d:timeout>Second-%u</d:timeout>"
                      "<d:locktoken>"
                      "<d:href>%s</d:href>"
                      "</d:locktoken>"
                      "</d:activelock>\n",
                      dav_lock[i].user,
                      (unsigned)LOCK_DURATION_S,
                      dav_lock[i].token);
        }
    }
 
    mg_printf(conn,
              "</d:lockdiscovery>"
              "</d:prop>"
              "<d:status>HTTP/1.1 200 OK</d:status>"
              "</d:propstat>"
              "</d:response>\n");
 
    mg_free(link_concat);
    return 1;
}
 
 
static int
print_dav_dir_entry(struct de *de, void *data)
{
    struct mg_connection *conn = (struct mg_connection *)data;
    if (!de || !conn
        || !print_props(
               conn, conn->request_info.local_uri, de->file_name, &de->file)) {
        /* stop scan */
        return 1;
    }
    return 0;
}
 
 
static void
handle_propfind(struct mg_connection *conn,
                const char *path,
                struct mg_file_stat *filep)
{
    const char *depth = mg_get_header(conn, "Depth");
 
    if (!conn || !path || !filep || !conn->dom_ctx) {
        return;
    }
 
    /* return 207 "Multi-Status" */
    conn->must_close = 1;
    mg_response_header_start(conn, 207);
    send_static_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn,
                           "Content-Type",
                           "application/xml; charset=utf-8",
                           -1);
    mg_response_header_send(conn);
 
    /* Content */
    mg_printf(conn,
              "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
              "<d:multistatus xmlns:d='DAV:'>\n");
 
    /* Print properties for the requested resource itself */
    print_props(conn, conn->request_info.local_uri, "", filep);
 
    /* If it is a directory, print directory entries too if Depth is not 0
     */
    if (filep->is_directory
        && !mg_strcasecmp(conn->dom_ctx->config[ENABLE_DIRECTORY_LISTING],
                          "yes")
        && ((depth == NULL) || (strcmp(depth, "0") != 0))) {
        scan_directory(conn, path, conn, &print_dav_dir_entry);
    }
 
    mg_printf(conn, "%s\n", "</d:multistatus>");
}
 
 
static void
dav_lock_file(struct mg_connection *conn, const char *path)
{
    /* internal function - therefore conn is assumed to be valid */
    char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */
    uint64_t new_locktime;
    int lock_index = -1;
    int i;
    uint64_t LOCK_DURATION_NS =
        (uint64_t)(LOCK_DURATION_S) * (uint64_t)1000000000;
    struct twebdav_lock *dav_lock = conn->phys_ctx->webdav_lock;
 
    if (!path || !conn->dom_ctx || !conn->request_info.remote_user) {
        return;
    }
    mg_get_request_link(conn, link_buf, sizeof(link_buf));
 
    /* const char *refresh = mg_get_header(conn, "If"); */
    /* Link refresh should have an "If" header:
     * http://www.webdav.org/specs/rfc2518.html#n-example---refreshing-a-write-lock
     * But it seems Windows Explorer does not send them.
     */
 
    mg_lock_context(conn->phys_ctx);
    new_locktime = mg_get_current_time_ns();
 
    /* Find a slot for a lock */
    while (lock_index < 0) {
        /* find existing lock */
        for (i = 0; i < NUM_WEBDAV_LOCKS; i++) {
            if (!strcmp(dav_lock[i].path, link_buf)) {
                if (!strcmp(conn->request_info.remote_user, dav_lock[i].user)) {
                    /* locked by the same user */
                    dav_lock[i].locktime = new_locktime;
                    lock_index = i;
                    break;
                } else {
                    /* already locked by someone else */
                    if (new_locktime
                        > (dav_lock[i].locktime + LOCK_DURATION_NS)) {
                        /* Lock expired */
                        dav_lock[i].path[0] = 0;
                    } else {
                        /* Lock still valid */
                        mg_unlock_context(conn->phys_ctx);
                        mg_send_http_error(conn, 423, "%s", "Already locked");
                        return;
                    }
                }
            }
        }
 
        /* create new lock token */
        for (i = 0; i < NUM_WEBDAV_LOCKS; i++) {
            if (dav_lock[i].path[0] == 0) {
                char s[32];
                dav_lock[i].locktime = mg_get_current_time_ns();
                sprintf(s, "%" UINT64_FMT, (uint64_t)dav_lock[i].locktime);
                mg_md5(dav_lock[i].token,
                       link_buf,
                       "\x01",
                       s,
                       "\x01",
                       conn->request_info.remote_user,
                       NULL);
                mg_strlcpy(dav_lock[i].path,
                           link_buf,
                           sizeof(dav_lock[i].path));
                mg_strlcpy(dav_lock[i].user,
                           conn->request_info.remote_user,
                           sizeof(dav_lock[i].user));
                lock_index = i;
                break;
            }
        }
        if (lock_index < 0) {
            /* too many locks. Find oldest lock */
            uint64_t oldest_locktime = dav_lock[0].locktime;
            lock_index = 0;
            for (i = 1; i < NUM_WEBDAV_LOCKS; i++) {
                if (dav_lock[i].locktime < oldest_locktime) {
                    oldest_locktime = dav_lock[i].locktime;
                    lock_index = i;
                }
            }
            /* invalidate oldest lock */
            dav_lock[lock_index].path[0] = 0;
        }
    }
    mg_unlock_context(conn->phys_ctx);
 
    /* return 200 "OK" */
    conn->must_close = 1;
    mg_response_header_start(conn, 200);
    send_static_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn,
                           "Content-Type",
                           "application/xml; charset=utf-8",
                           -1);
    mg_response_header_add(conn, "Lock-Token", dav_lock[lock_index].token, -1);
    mg_response_header_send(conn);
 
    /* Content */
    mg_printf(conn,
              "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
              "<d:prop xmlns:d=\"DAV:\">\n"
              "     <d:lockdiscovery>\n"
              "       <d:activelock>\n"
              "         <d:lockscope><d:exclusive/></d:lockscope>\n"
              "         <d:locktype><d:write/></d:locktype>\n"
              "         <d:owner>\n"
              "           <d:href>%s</d:href>\n"
              "         </d:owner>\n"
              "         <d:timeout>Second-%u</d:timeout>\n"
              "         <d:locktoken><d:href>%s</d:href></d:locktoken>\n"
              "         <d:lockroot>\n"
              "           <d:href>%s</d:href>\n"
              "         </d:lockroot>\n"
              "       </d:activelock>\n"
              "     </d:lockdiscovery>\n"
              "   </d:prop>\n",
              dav_lock[lock_index].user,
              (LOCK_DURATION_S),
              dav_lock[lock_index].token,
              dav_lock[lock_index].path);
}
 
 
static void
dav_unlock_file(struct mg_connection *conn, const char *path)
{
    /* internal function - therefore conn is assumed to be valid */
    char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */
    struct twebdav_lock *dav_lock = conn->phys_ctx->webdav_lock;
    int lock_index;
 
    if (!path || !conn->dom_ctx || !conn->request_info.remote_user) {
        return;
    }
 
    mg_get_request_link(conn, link_buf, sizeof(link_buf));
 
    mg_lock_context(conn->phys_ctx);
    /* find existing lock */
    for (lock_index = 0; lock_index < NUM_WEBDAV_LOCKS; lock_index++) {
        if (!strcmp(dav_lock[lock_index].path, link_buf)) {
            /* Success: return 204 "No Content" */
            mg_unlock_context(conn->phys_ctx);
            conn->must_close = 1;
            mg_response_header_start(conn, 204);
            mg_response_header_send(conn);
            return;
        }
    }
    mg_unlock_context(conn->phys_ctx);
 
    /* Error: Cannot unlock a resource that is not locked */
    mg_send_http_error(conn, 423, "%s", "Lock not found");
}
 
 
static void
dav_proppatch(struct mg_connection *conn, const char *path)
{
    char link_buf[UTF8_PATH_MAX * 2]; /* Path + server root */
 
    if (!conn || !path || !conn->dom_ctx) {
        return;
    }
 
    /* return 207 "Multi-Status" */
    conn->must_close = 1;
    mg_response_header_start(conn, 207);
    send_static_cache_header(conn);
    send_additional_header(conn);
    mg_response_header_add(conn,
                           "Content-Type",
                           "application/xml; charset=utf-8",
                           -1);
    mg_response_header_send(conn);
 
    mg_get_request_link(conn, link_buf, sizeof(link_buf));
 
    /* Content */
    mg_printf(conn,
              "<?xml version=\"1.0\" encoding=\"utf-8\"?>"
              "<d:multistatus xmlns:d='DAV:'>\n"
              "<d:response>\n<d:href>%s</d:href>\n",
              link_buf);
    mg_printf(conn,
              "<d:propstat><d:status>HTTP/1.1 403 "
              "Forbidden</d:status></d:propstat>\n");
    mg_printf(conn, "%s\n", "</d:response></d:multistatus>");
}
#endif
 
 
CIVETWEB_API void
mg_lock_connection(struct mg_connection *conn)
{
    if (conn) {
        (void)pthread_mutex_lock(&conn->mutex);
    }
}
 
 
CIVETWEB_API void
mg_unlock_connection(struct mg_connection *conn)
{
    if (conn) {
        (void)pthread_mutex_unlock(&conn->mutex);
    }
}
 
 
CIVETWEB_API void
mg_lock_context(struct mg_context *ctx)
{
    if (ctx && (ctx->context_type == CONTEXT_SERVER)) {
        (void)pthread_mutex_lock(&ctx->nonce_mutex);
    }
}
 
 
CIVETWEB_API void
mg_unlock_context(struct mg_context *ctx)
{
    if (ctx && (ctx->context_type == CONTEXT_SERVER)) {
        (void)pthread_mutex_unlock(&ctx->nonce_mutex);
    }
}
 
 
#if defined(USE_LUA)
#include "mod_lua.inl"
#endif /* USE_LUA */
 
#if defined(USE_DUKTAPE)
#include "mod_duktape.inl"
#endif /* USE_DUKTAPE */
 
#if defined(USE_WEBSOCKET)
 
#if !defined(NO_SSL_DL)
#if !defined(OPENSSL_API_3_0)
#define SHA_API static
#include "sha1.inl"
#endif
#endif
 
static int
send_websocket_handshake(struct mg_connection *conn, const char *websock_key)
{
    static const char *magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
    char buf[100], sha[20], b64_sha[sizeof(sha) * 2];
    size_t dst_len = sizeof(b64_sha);
#if !defined(OPENSSL_API_3_0)
    SHA_CTX sha_ctx;
#endif
    int truncated;
 
    /* Calculate Sec-WebSocket-Accept reply from Sec-WebSocket-Key. */
    mg_snprintf(conn, &truncated, buf, sizeof(buf), "%s%s", websock_key, magic);
    if (truncated) {
        conn->must_close = 1;
        return 0;
    }
 
    DEBUG_TRACE("%s", "Send websocket handshake");
 
#if defined(OPENSSL_API_3_0)
    EVP_Digest((unsigned char *)buf,
               (uint32_t)strlen(buf),
               (unsigned char *)sha,
               NULL,
               EVP_get_digestbyname("sha1"),
               NULL);
#else
    SHA1_Init(&sha_ctx);
    SHA1_Update(&sha_ctx, (unsigned char *)buf, (uint32_t)strlen(buf));
    SHA1_Final((unsigned char *)sha, &sha_ctx);
#endif
    mg_base64_encode((unsigned char *)sha, sizeof(sha), b64_sha, &dst_len);
    mg_printf(conn,
              "HTTP/1.1 101 Switching Protocols\r\n"
              "Upgrade: websocket\r\n"
              "Connection: Upgrade\r\n"
              "Sec-WebSocket-Accept: %s\r\n",
              b64_sha);
 
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
    // Send negotiated compression extension parameters
    websocket_deflate_response(conn);
#endif
 
    if (conn->request_info.acceptedWebSocketSubprotocol) {
        mg_printf(conn,
                  "Sec-WebSocket-Protocol: %s\r\n\r\n",
                  conn->request_info.acceptedWebSocketSubprotocol);
    } else {
        mg_printf(conn, "%s", "\r\n");
    }
 
    return 1;
}
 
 
#if !defined(MG_MAX_UNANSWERED_PING)
/* Configuration of the maximum number of websocket PINGs that might
 * stay unanswered before the connection is considered broken.
 * Note: The name of this define may still change (until it is
 * defined as a compile parameter in a documentation).
 */
#define MG_MAX_UNANSWERED_PING (5)
#endif
 
 
static void
read_websocket(struct mg_connection *conn,
               mg_websocket_data_handler ws_data_handler,
               void *callback_data)
{
    /* Pointer to the beginning of the portion of the incoming websocket
     * message queue.
     * The original websocket upgrade request is never removed, so the queue
     * begins after it. */
    unsigned char *buf = (unsigned char *)conn->buf + conn->request_len;
    int n, error, exit_by_callback;
    int ret;
 
    /* body_len is the length of the entire queue in bytes
     * len is the length of the current message
     * data_len is the length of the current message's data payload
     * header_len is the length of the current message's header */
    size_t i, len, mask_len = 0, header_len, body_len;
    uint64_t data_len = 0;
 
    /* "The masking key is a 32-bit value chosen at random by the client."
     * http://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-17#section-5
     */
    unsigned char mask[4];
 
    /* data points to the place where the message is stored when passed to
     * the websocket_data callback.  This is either mem on the stack, or a
     * dynamically allocated buffer if it is too large. */
    unsigned char mem[4096];
    unsigned char mop; /* mask flag and opcode */
 
    /* Variables used for connection monitoring */
    double timeout = -1.0;
    int enable_ping_pong = 0;
    int ping_count = 0;
 
    if (conn->dom_ctx->config[ENABLE_WEBSOCKET_PING_PONG]) {
        enable_ping_pong =
            !mg_strcasecmp(conn->dom_ctx->config[ENABLE_WEBSOCKET_PING_PONG],
                           "yes");
    }
 
    if (conn->dom_ctx->config[WEBSOCKET_TIMEOUT]) {
        timeout = atoi(conn->dom_ctx->config[WEBSOCKET_TIMEOUT]) / 1000.0;
    }
    if ((timeout <= 0.0) && (conn->dom_ctx->config[REQUEST_TIMEOUT])) {
        timeout = atoi(conn->dom_ctx->config[REQUEST_TIMEOUT]) / 1000.0;
    }
    if (timeout <= 0.0) {
        timeout = atof(config_options[REQUEST_TIMEOUT].default_value) / 1000.0;
    }
 
    /* Enter data processing loop */
    DEBUG_TRACE("Websocket connection %s:%u start data processing loop",
                conn->request_info.remote_addr,
                conn->request_info.remote_port);
    conn->in_websocket_handling = 1;
    mg_set_thread_name("wsock");
 
    /* Loop continuously, reading messages from the socket, invoking the
     * callback, and waiting repeatedly until an error occurs. */
    while (STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)
           && (!conn->must_close)) {
        header_len = 0;
        DEBUG_ASSERT(conn->data_len >= conn->request_len);
        if ((body_len = (size_t)(conn->data_len - conn->request_len)) >= 2) {
            len = buf[1] & 127;
            mask_len = (buf[1] & 128) ? 4 : 0;
            if ((len < 126) && (body_len >= mask_len)) {
                /* inline 7-bit length field */
                data_len = len;
                header_len = 2 + mask_len;
            } else if ((len == 126) && (body_len >= (4 + mask_len))) {
                /* 16-bit length field */
                header_len = 4 + mask_len;
                data_len = ((((size_t)buf[2]) << 8) + buf[3]);
            } else if (body_len >= (10 + mask_len)) {
                /* 64-bit length field */
                uint32_t l1, l2;
                memcpy(&l1, &buf[2], 4); /* Use memcpy for alignment */
                memcpy(&l2, &buf[6], 4);
                header_len = 10 + mask_len;
                data_len = (((uint64_t)ntohl(l1)) << 32) + ntohl(l2);
 
                if (data_len > (uint64_t)0x7FFF0000ul) {
                    /* no can do */
                    mg_cry_internal(
                        conn,
                        "%s",
                        "websocket out of memory; closing connection");
                    break;
                }
            }
        }
 
        if ((header_len > 0) && (body_len >= header_len)) {
            /* Allocate space to hold websocket payload */
            unsigned char *data = mem;
 
            if ((size_t)data_len > (size_t)sizeof(mem)) {
                data = (unsigned char *)mg_malloc_ctx((size_t)data_len,
                                                      conn->phys_ctx);
                if (data == NULL) {
                    /* Allocation failed, exit the loop and then close the
                     * connection */
                    mg_cry_internal(
                        conn,
                        "%s",
                        "websocket out of memory; closing connection");
                    break;
                }
            }
 
            /* Copy the mask before we shift the queue and destroy it */
            if (mask_len > 0) {
                memcpy(mask, buf + header_len - mask_len, sizeof(mask));
            } else {
                memset(mask, 0, sizeof(mask));
            }
 
            /* Read frame payload from the first message in the queue into
             * data and advance the queue by moving the memory in place. */
            DEBUG_ASSERT(body_len >= header_len);
            if (data_len + (uint64_t)header_len > (uint64_t)body_len) {
                mop = buf[0]; /* current mask and opcode */
                              /* Overflow case */
                len = body_len - header_len;
                memcpy(data, buf + header_len, len);
                error = 0;
                while ((uint64_t)len < data_len) {
                    n = pull_inner(NULL,
                                   conn,
                                   (char *)(data + len),
                                   (int)(data_len - len),
                                   timeout);
                    if (n <= -2) {
                        error = 1;
                        break;
                    } else if (n > 0) {
                        len += (size_t)n;
                    } else {
                        /* Timeout: should retry */
                        /* TODO: retry condition */
                    }
                }
                if (error) {
                    mg_cry_internal(
                        conn,
                        "%s",
                        "Websocket pull failed; closing connection");
                    if (data != mem) {
                        mg_free(data);
                    }
                    break;
                }
 
                conn->data_len = conn->request_len;
 
            } else {
 
                mop = buf[0]; /* current mask and opcode, overwritten by
                               * memmove() */
 
                /* Length of the message being read at the front of the
                 * queue. Cast to 31 bit is OK, since we limited
                 * data_len before. */
                len = (size_t)data_len + header_len;
 
                /* Copy the data payload into the data pointer for the
                 * callback. Cast to 31 bit is OK, since we
                 * limited data_len */
                memcpy(data, buf + header_len, (size_t)data_len);
 
                /* Move the queue forward len bytes */
                memmove(buf, buf + len, body_len - len);
 
                /* Mark the queue as advanced */
                conn->data_len -= (int)len;
            }
 
            /* Apply mask if necessary */
            if (mask_len > 0) {
                for (i = 0; i < (size_t)data_len; i++) {
                    data[i] ^= mask[i & 3];
                }
            }
 
            exit_by_callback = 0;
            if (enable_ping_pong && ((mop & 0xF) == MG_WEBSOCKET_OPCODE_PONG)) {
                /* filter PONG messages */
                DEBUG_TRACE("PONG from %s:%u",
                            conn->request_info.remote_addr,
                            conn->request_info.remote_port);
                /* No unanwered PINGs left */
                ping_count = 0;
            } else if (enable_ping_pong
                       && ((mop & 0xF) == MG_WEBSOCKET_OPCODE_PING)) {
                /* reply PING messages */
                DEBUG_TRACE("Reply PING from %s:%u",
                            conn->request_info.remote_addr,
                            conn->request_info.remote_port);
                ret = mg_websocket_write(conn,
                                         MG_WEBSOCKET_OPCODE_PONG,
                                         (char *)data,
                                         (size_t)data_len);
                if (ret <= 0) {
                    /* Error: send failed */
                    DEBUG_TRACE("Reply PONG failed (%i)", ret);
                    break;
                }
 
            } else {
                /* Exit the loop if callback signals to exit (server side),
                 * or "connection close" opcode received (client side). */
                if (ws_data_handler != NULL) {
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
                    if (mop & 0x40) {
                        /* Inflate the data received if bit RSV1 is set. */
                        if (!conn->websocket_deflate_initialized) {
                            if (websocket_deflate_initialize(conn, 1) != Z_OK)
                                exit_by_callback = 1;
                        }
                        if (!exit_by_callback) {
                            size_t inflate_buf_size_old = 0;
                            size_t inflate_buf_size =
                                data_len
                                * 4; // Initial guess of the inflated message
                                     // size. We double the memory when needed.
                            Bytef *inflated = NULL;
                            Bytef *new_mem = NULL;
                            conn->websocket_inflate_state.avail_in =
                                (uInt)(data_len + 4);
                            conn->websocket_inflate_state.next_in = data;
                            // Add trailing 0x00 0x00 0xff 0xff bytes
                            data[data_len] = '\x00';
                            data[data_len + 1] = '\x00';
                            data[data_len + 2] = '\xff';
                            data[data_len + 3] = '\xff';
                            do {
                                if (inflate_buf_size_old == 0) {
                                    new_mem =
                                        (Bytef *)mg_calloc(inflate_buf_size,
                                                           sizeof(Bytef));
                                } else {
                                    inflate_buf_size *= 2;
                                    new_mem =
                                        (Bytef *)mg_realloc(inflated,
                                                            inflate_buf_size);
                                }
                                if (new_mem == NULL) {
                                    mg_cry_internal(
                                        conn,
                                        "Out of memory: Cannot allocate "
                                        "inflate buffer of %lu bytes",
                                        (unsigned long)inflate_buf_size);
                                    exit_by_callback = 1;
                                    break;
                                }
                                inflated = new_mem;
                                conn->websocket_inflate_state.avail_out =
                                    (uInt)(inflate_buf_size
                                           - inflate_buf_size_old);
                                conn->websocket_inflate_state.next_out =
                                    inflated + inflate_buf_size_old;
                                ret = inflate(&conn->websocket_inflate_state,
                                              Z_SYNC_FLUSH);
                                if (ret == Z_NEED_DICT || ret == Z_DATA_ERROR
                                    || ret == Z_MEM_ERROR) {
                                    mg_cry_internal(
                                        conn,
                                        "ZLIB inflate error: %i %s",
                                        ret,
                                        (conn->websocket_inflate_state.msg
                                             ? conn->websocket_inflate_state.msg
                                             : "<no error message>"));
                                    exit_by_callback = 1;
                                    break;
                                }
                                inflate_buf_size_old = inflate_buf_size;
 
                            } while (conn->websocket_inflate_state.avail_out
                                     == 0);
                            inflate_buf_size -=
                                conn->websocket_inflate_state.avail_out;
                            if (!ws_data_handler(conn,
                                                 mop,
                                                 (char *)inflated,
                                                 inflate_buf_size,
                                                 callback_data)) {
                                exit_by_callback = 1;
                            }
                            mg_free(inflated);
                        }
                    } else
#endif
                        if (!ws_data_handler(conn,
                                             mop,
                                             (char *)data,
                                             (size_t)data_len,
                                             callback_data)) {
                        exit_by_callback = 1;
                    }
                }
            }
 
            /* It a buffer has been allocated, free it again */
            if (data != mem) {
                mg_free(data);
            }
 
            if (exit_by_callback) {
                DEBUG_TRACE("Callback requests to close connection from %s:%u",
                            conn->request_info.remote_addr,
                            conn->request_info.remote_port);
                break;
            }
            if ((mop & 0xf) == MG_WEBSOCKET_OPCODE_CONNECTION_CLOSE) {
                /* Opcode == 8, connection close */
                DEBUG_TRACE("Message requests to close connection from %s:%u",
                            conn->request_info.remote_addr,
                            conn->request_info.remote_port);
                break;
            }
 
            /* Not breaking the loop, process next websocket frame. */
        } else {
            /* Read from the socket into the next available location in the
             * message queue. */
            n = pull_inner(NULL,
                           conn,
                           conn->buf + conn->data_len,
                           conn->buf_size - conn->data_len,
                           timeout);
            if (n <= -2) {
                /* Error, no bytes read */
                DEBUG_TRACE("PULL from %s:%u failed",
                            conn->request_info.remote_addr,
                            conn->request_info.remote_port);
                break;
            }
            if (n > 0) {
                conn->data_len += n;
                /* Reset open PING count */
                ping_count = 0;
            } else {
                if (STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)
                    && (!conn->must_close)) {
                    if (ping_count > MG_MAX_UNANSWERED_PING) {
                        /* Stop sending PING */
                        DEBUG_TRACE("Too many (%i) unanswered ping from %s:%u "
                                    "- closing connection",
                                    ping_count,
                                    conn->request_info.remote_addr,
                                    conn->request_info.remote_port);
                        break;
                    }
                    if (enable_ping_pong) {
                        /* Send Websocket PING message */
                        DEBUG_TRACE("PING to %s:%u",
                                    conn->request_info.remote_addr,
                                    conn->request_info.remote_port);
                        ret = mg_websocket_write(conn,
                                                 MG_WEBSOCKET_OPCODE_PING,
                                                 NULL,
                                                 0);
 
                        if (ret <= 0) {
                            /* Error: send failed */
                            DEBUG_TRACE("Send PING failed (%i)", ret);
                            break;
                        }
                        ping_count++;
                    }
                }
                /* Timeout: should retry */
                /* TODO: get timeout def */
            }
        }
    }
 
    /* Leave data processing loop */
    mg_set_thread_name("worker");
    conn->in_websocket_handling = 0;
    DEBUG_TRACE("Websocket connection %s:%u left data processing loop",
                conn->request_info.remote_addr,
                conn->request_info.remote_port);
}
 
 
static int
mg_websocket_write_exec(struct mg_connection *conn,
                        int opcode,
                        const char *data,
                        size_t dataLen,
                        uint32_t masking_key)
{
    unsigned char header[14];
    size_t headerLen;
    int retval;
 
#if defined(GCC_DIAGNOSTIC)
    /* Disable spurious conversion warning for GCC */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wconversion"
#endif
 
    /* Note that POSIX/Winsock's send() is threadsafe
     * http://stackoverflow.com/questions/1981372/are-parallel-calls-to-send-recv-on-the-same-socket-valid
     * but mongoose's mg_printf/mg_write is not (because of the loop in
     * push(), although that is only a problem if the packet is large or
     * outgoing buffer is full). */
 
    /* TODO: Check if this lock should be moved to user land.
     * Currently the server sets this lock for websockets, but
     * not for any other connection. It must be set for every
     * conn read/written by more than one thread, no matter if
     * it is a websocket or regular connection. */
    (void)mg_lock_connection(conn);
 
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
    size_t deflated_size = 0;
    Bytef *deflated = 0;
    // Deflate websocket messages over 100kb
    int use_deflate = dataLen > 100 * 1024 && conn->accept_gzip;
 
    if (use_deflate) {
        if (!conn->websocket_deflate_initialized) {
            if (websocket_deflate_initialize(conn, 1) != Z_OK)
                return 0;
        }
 
        // Deflating the message
        header[0] = 0xC0u | (unsigned char)((unsigned)opcode & 0xf);
        conn->websocket_deflate_state.avail_in = (uInt)dataLen;
        conn->websocket_deflate_state.next_in = (unsigned char *)data;
        deflated_size = (size_t)compressBound((uLong)dataLen);
        deflated = mg_calloc(deflated_size, sizeof(Bytef));
        if (deflated == NULL) {
            mg_cry_internal(
                conn,
                "Out of memory: Cannot allocate deflate buffer of %lu bytes",
                (unsigned long)deflated_size);
            mg_unlock_connection(conn);
            return -1;
        }
        conn->websocket_deflate_state.avail_out = (uInt)deflated_size;
        conn->websocket_deflate_state.next_out = deflated;
        deflate(&conn->websocket_deflate_state, conn->websocket_deflate_flush);
        dataLen = deflated_size - conn->websocket_deflate_state.avail_out
                  - 4; // Strip trailing 0x00 0x00 0xff 0xff bytes
    } else
#endif
        header[0] = 0x80u | (unsigned char)((unsigned)opcode & 0xf);
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif
 
    /* Frame format: http://tools.ietf.org/html/rfc6455#section-5.2 */
    if (dataLen < 126) {
        /* inline 7-bit length field */
        header[1] = (unsigned char)dataLen;
        headerLen = 2;
    } else if (dataLen <= 0xFFFF) {
        /* 16-bit length field */
        uint16_t len = htons((uint16_t)dataLen);
        header[1] = 126;
        memcpy(header + 2, &len, 2);
        headerLen = 4;
    } else {
        /* 64-bit length field */
        uint32_t len1 = htonl((uint32_t)((uint64_t)dataLen >> 32));
        uint32_t len2 = htonl((uint32_t)(dataLen & 0xFFFFFFFFu));
        header[1] = 127;
        memcpy(header + 2, &len1, 4);
        memcpy(header + 6, &len2, 4);
        headerLen = 10;
    }
 
    if (masking_key) {
        /* add mask */
        header[1] |= 0x80;
        memcpy(header + headerLen, &masking_key, 4);
        headerLen += 4;
    }
 
    retval = mg_write(conn, header, headerLen);
    if (retval != (int)headerLen) {
        /* Did not send complete header */
        retval = -1;
    } else {
        if (dataLen > 0) {
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
            if (use_deflate) {
                retval = mg_write(conn, deflated, dataLen);
                mg_free(deflated);
            } else
#endif
                retval = mg_write(conn, data, dataLen);
        }
        /* if dataLen == 0, the header length (2) is returned */
    }
 
    /* TODO: Remove this unlock as well, when lock is removed. */
    mg_unlock_connection(conn);
 
    return retval;
}
 
 
CIVETWEB_API int
mg_websocket_write(struct mg_connection *conn,
                   int opcode,
                   const char *data,
                   size_t dataLen)
{
    return mg_websocket_write_exec(conn, opcode, data, dataLen, 0);
}
 
 
static void
mask_data(const char *in, size_t in_len, uint32_t masking_key, char *out)
{
    size_t i = 0;
 
    i = 0;
    if ((in_len > 3) && ((ptrdiff_t)in % 4) == 0) {
        /* Convert in 32 bit words, if data is 4 byte aligned */
        while (i < (in_len - 3)) {
            *(uint32_t *)(void *)(out + i) =
                *(uint32_t *)(void *)(in + i) ^ masking_key;
            i += 4;
        }
    }
    if (i != in_len) {
        /* convert 1-3 remaining bytes if ((dataLen % 4) != 0)*/
        while (i < in_len) {
            *(uint8_t *)(void *)(out + i) =
                *(uint8_t *)(void *)(in + i)
                ^ *(((uint8_t *)&masking_key) + (i % 4));
            i++;
        }
    }
}
 
 
CIVETWEB_API int
mg_websocket_client_write(struct mg_connection *conn,
                          int opcode,
                          const char *data,
                          size_t dataLen)
{
    int retval = -1;
    char *masked_data =
        (char *)mg_malloc_ctx(((dataLen + 7) / 4) * 4, conn->phys_ctx);
    uint32_t masking_key = 0;
 
    if (masked_data == NULL) {
        /* Return -1 in an error case */
        mg_cry_internal(conn,
                        "%s",
                        "Cannot allocate buffer for masked websocket response: "
                        "Out of memory");
        return -1;
    }
 
    do {
        /* Get a masking key - but not 0 */
        masking_key = (uint32_t)get_random();
    } while (masking_key == 0);
 
    mask_data(data, dataLen, masking_key, masked_data);
 
    retval = mg_websocket_write_exec(
        conn, opcode, masked_data, dataLen, masking_key);
    mg_free(masked_data);
 
    return retval;
}
 
 
static void
handle_websocket_request(struct mg_connection *conn,
                         const char *path,
                         int is_callback_resource,
                         struct mg_websocket_subprotocols *subprotocols,
                         mg_websocket_connect_handler ws_connect_handler,
                         mg_websocket_ready_handler ws_ready_handler,
                         mg_websocket_data_handler ws_data_handler,
                         mg_websocket_close_handler ws_close_handler,
                         void *cbData)
{
    const char *websock_key = mg_get_header(conn, "Sec-WebSocket-Key");
    const char *version = mg_get_header(conn, "Sec-WebSocket-Version");
    ptrdiff_t lua_websock = 0;
 
#if !defined(USE_LUA)
    (void)path;
#endif
 
    /* Step 1: Check websocket protocol version. */
    /* Step 1.1: Check Sec-WebSocket-Key. */
    if (!websock_key) {
        /* The RFC standard version (https://tools.ietf.org/html/rfc6455)
         * requires a Sec-WebSocket-Key header.
         */
        /* It could be the hixie draft version
         * (http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol-76).
         */
        const char *key1 = mg_get_header(conn, "Sec-WebSocket-Key1");
        const char *key2 = mg_get_header(conn, "Sec-WebSocket-Key2");
        char key3[8];
 
        if ((key1 != NULL) && (key2 != NULL)) {
            /* This version uses 8 byte body data in a GET request */
            conn->content_len = 8;
            if (8 == mg_read(conn, key3, 8)) {
                /* This is the hixie version */
                mg_send_http_error(conn,
                                   426,
                                   "%s",
                                   "Protocol upgrade to RFC 6455 required");
                return;
            }
        }
        /* This is an unknown version */
        mg_send_http_error(conn, 400, "%s", "Malformed websocket request");
        return;
    }
 
    /* Step 1.2: Check websocket protocol version. */
    /* The RFC version (https://tools.ietf.org/html/rfc6455) is 13. */
    if ((version == NULL) || (strcmp(version, "13") != 0)) {
        /* Reject wrong versions */
        mg_send_http_error(conn, 426, "%s", "Protocol upgrade required");
        return;
    }
 
    /* Step 1.3: Could check for "Host", but we do not really need this
     * value for anything, so just ignore it. */
 
    /* Step 2: If a callback is responsible, call it. */
    if (is_callback_resource) {
        /* Step 2.1 check and select subprotocol */
        const char *protocols[64]; // max 64 headers
        int nbSubprotocolHeader = get_req_headers(&conn->request_info,
                                                  "Sec-WebSocket-Protocol",
                                                  protocols,
                                                  64);
 
        if ((nbSubprotocolHeader > 0) && subprotocols) {
 
            int headerNo, idx;
            size_t len;
            const char *sep, *curSubProtocol,
                *acceptedWebSocketSubprotocol = NULL;
 
            /* look for matching subprotocol */
            for (headerNo = 0; headerNo < nbSubprotocolHeader; headerNo++) {
                /* There might be multiple headers ... */
                const char *protocol = protocols[headerNo];
                curSubProtocol = protocol;
 
                /* ... and in every header there might be a , separated list */
                while (!acceptedWebSocketSubprotocol && (*curSubProtocol)) {
 
                    while ((*curSubProtocol == ' ') || (*curSubProtocol == ','))
                        curSubProtocol++;
                    sep = strchr(curSubProtocol, ',');
                    if (sep) {
                        len = (size_t)(sep - curSubProtocol);
                    } else {
                        len = strlen(curSubProtocol);
                    }
 
                    for (idx = 0; idx < subprotocols->nb_subprotocols; idx++) {
                        // COMPARE: curSubProtocol ==
                        // subprotocols->subprotocols[idx]
                        if ((strlen(subprotocols->subprotocols[idx]) == len)
                            && (strncmp(curSubProtocol,
                                        subprotocols->subprotocols[idx],
                                        len)
                                == 0)) {
                            acceptedWebSocketSubprotocol =
                                subprotocols->subprotocols[idx];
                            break;
                        }
                    }
                    curSubProtocol += len;
                }
            }
 
            conn->request_info.acceptedWebSocketSubprotocol =
                acceptedWebSocketSubprotocol;
        }
 
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
        websocket_deflate_negotiate(conn);
#endif
 
        if ((ws_connect_handler != NULL)
            && (ws_connect_handler(conn, cbData) != 0)) {
            /* C callback has returned non-zero, do not proceed with
             * handshake.
             */
            /* Note that C callbacks are no longer called when Lua is
             * responsible, so C can no longer filter callbacks for Lua. */
            return;
        }
    }
 
#if defined(USE_LUA)
    /* Step 3: No callback. Check if Lua is responsible. */
    else {
        /* Step 3.1: Check if Lua is responsible. */
        if (conn->dom_ctx->config[LUA_WEBSOCKET_EXTENSIONS]) {
            lua_websock = match_prefix_strlen(
                conn->dom_ctx->config[LUA_WEBSOCKET_EXTENSIONS], path);
        }
 
        if (lua_websock > 0) {
            /* Step 3.2: Lua is responsible: call it. */
            conn->lua_websocket_state = lua_websocket_new(path, conn);
            if (!conn->lua_websocket_state) {
                /* Lua rejected the new client */
                return;
            }
        }
    }
#endif
 
    /* Step 4: Check if there is a responsible websocket handler. */
    if (!is_callback_resource && !lua_websock) {
        /* There is no callback, and Lua is not responsible either. */
        /* Reply with a 404 Not Found. We are still at a standard
         * HTTP request here, before the websocket handshake, so
         * we can still send standard HTTP error replies. */
        mg_send_http_error(conn, 404, "%s", "Not found");
        return;
    }
 
    /* Step 5: The websocket connection has been accepted */
    if (!send_websocket_handshake(conn, websock_key)) {
        mg_send_http_error(conn, 500, "%s", "Websocket handshake failed");
        return;
    }
 
    /* Step 6: Call the ready handler */
    if (is_callback_resource) {
        if (ws_ready_handler != NULL) {
            ws_ready_handler(conn, cbData);
        }
#if defined(USE_LUA)
    } else if (lua_websock) {
        if (!lua_websocket_ready(conn, conn->lua_websocket_state)) {
            /* the ready handler returned false */
            return;
        }
#endif
    }
 
    /* Step 7: Enter the read loop */
    if (is_callback_resource) {
        read_websocket(conn, ws_data_handler, cbData);
#if defined(USE_LUA)
    } else if (lua_websock) {
        read_websocket(conn, lua_websocket_data, conn->lua_websocket_state);
#endif
    }
 
#if defined(USE_ZLIB) && defined(MG_EXPERIMENTAL_INTERFACES)
    /* Step 8: Close the deflate & inflate buffers */
    if (conn->websocket_deflate_initialized) {
        deflateEnd(&conn->websocket_deflate_state);
        inflateEnd(&conn->websocket_inflate_state);
    }
#endif
 
    /* Step 9: Call the close handler */
    if (ws_close_handler) {
        ws_close_handler(conn, cbData);
    }
}
#endif /* !USE_WEBSOCKET */
 
 
/* Is upgrade request:
 *   0 = regular HTTP/1.0 or HTTP/1.1 request
 *   1 = upgrade to websocket
 *   2 = upgrade to HTTP/2
 * -1 = upgrade to unknown protocol
 */
static int
should_switch_to_protocol(const struct mg_connection *conn)
{
    const char *connection_headers[8];
    const char *upgrade_to;
    int connection_header_count, i, should_upgrade;
 
    /* A websocket protocol has the following HTTP headers:
     *
     * Connection: Upgrade
     * Upgrade: Websocket
     *
     * It seems some clients use multiple headers:
     * see https://github.com/civetweb/civetweb/issues/1083
     */
    connection_header_count = get_req_headers(&conn->request_info,
                                              "Connection",
                                              connection_headers,
                                              8);
    should_upgrade = 0;
    for (i = 0; i < connection_header_count; i++) {
        if (0 != mg_strcasestr(connection_headers[i], "upgrade")) {
            should_upgrade = 1;
        }
    }
    if (!should_upgrade) {
        return PROTOCOL_TYPE_HTTP1;
    }
 
    upgrade_to = mg_get_header(conn, "Upgrade");
    if (upgrade_to == NULL) {
        /* "Connection: Upgrade" without "Upgrade" Header --> Error */
        return -1;
    }
 
    /* Upgrade to ... */
    if (0 != mg_strcasestr(upgrade_to, "websocket")) {
        /* The headers "Host", "Sec-WebSocket-Key", "Sec-WebSocket-Protocol" and
         * "Sec-WebSocket-Version" are also required.
         * Don't check them here, since even an unsupported websocket protocol
         * request still IS a websocket request (in contrast to a standard HTTP
         * request). It will fail later in handle_websocket_request.
         */
        return PROTOCOL_TYPE_WEBSOCKET; /* Websocket */
    }
    if (0 != mg_strcasestr(upgrade_to, "h2")) {
        return PROTOCOL_TYPE_HTTP2; /* Websocket */
    }
 
    /* Upgrade to another protocol */
    return -1;
}
 
 
static int
parse_match_net(const struct vec *vec, const union usa *sa, int no_strict)
{
    int n;
    unsigned int a, b, c, d, slash;
 
    if (sscanf(vec->ptr, "%u.%u.%u.%u/%u%n", &a, &b, &c, &d, &slash, &n)
        != 5) { // NOLINT(cert-err34-c) 'sscanf' used to convert a string to an
                // integer value, but function will not report conversion
                // errors; consider using 'strtol' instead
        slash = 32;
        if (sscanf(vec->ptr, "%u.%u.%u.%u%n", &a, &b, &c, &d, &n)
            != 4) { // NOLINT(cert-err34-c) 'sscanf' used to convert a string to
                    // an integer value, but function will not report conversion
                    // errors; consider using 'strtol' instead
            n = 0;
        }
    }
 
    if ((n > 0) && ((size_t)n == vec->len)) {
        if ((a < 256) && (b < 256) && (c < 256) && (d < 256) && (slash < 33)) {
            /* IPv4 format */
            if (sa->sa.sa_family == AF_INET) {
                uint32_t ip = ntohl(sa->sin.sin_addr.s_addr);
                uint32_t net = ((uint32_t)a << 24) | ((uint32_t)b << 16)
                               | ((uint32_t)c << 8) | (uint32_t)d;
                uint32_t mask = slash ? (0xFFFFFFFFu << (32 - slash)) : 0;
                return (ip & mask) == net;
            }
            return 0;
        }
    }
#if defined(USE_IPV6)
    else {
        char ad[50];
        const char *p;
 
        if (sscanf(vec->ptr, "[%49[^]]]/%u%n", ad, &slash, &n) != 2) {
            slash = 128;
            if (sscanf(vec->ptr, "[%49[^]]]%n", ad, &n) != 1) {
                n = 0;
            }
        }
 
        if ((n <= 0) && no_strict) {
            /* no square brackets? */
            p = strchr(vec->ptr, '/');
            if (p && (p < (vec->ptr + vec->len))) {
                if (((size_t)(p - vec->ptr) < sizeof(ad))
                    && (sscanf(p, "/%u%n", &slash, &n) == 1)) {
                    n += (int)(p - vec->ptr);
                    mg_strlcpy(ad, vec->ptr, (size_t)(p - vec->ptr) + 1);
                } else {
                    n = 0;
                }
            } else if (vec->len < sizeof(ad)) {
                n = (int)vec->len;
                slash = 128;
                mg_strlcpy(ad, vec->ptr, vec->len + 1);
            }
        }
 
        if ((n > 0) && ((size_t)n == vec->len) && (slash < 129)) {
            p = ad;
            c = 0;
            /* zone indexes are unsupported, at least two colons are needed */
            while (isxdigit((unsigned char)*p) || (*p == '.') || (*p == ':')) {
                if (*(p++) == ':') {
                    c++;
                }
            }
            if ((*p == '\0') && (c >= 2)) {
                struct sockaddr_in6 sin6;
                unsigned int i;
 
                /* for strict validation, an actual IPv6 argument is needed */
                if (sa->sa.sa_family != AF_INET6) {
                    return 0;
                }
                if (mg_inet_pton(AF_INET6, ad, &sin6, sizeof(sin6), 0)) {
                    /* IPv6 format */
                    for (i = 0; i < 16; i++) {
                        uint8_t ip = sa->sin6.sin6_addr.s6_addr[i];
                        uint8_t net = sin6.sin6_addr.s6_addr[i];
                        uint8_t mask = 0;
 
                        if (8 * i + 8 < slash) {
                            mask = 0xFFu;
                        } else if (8 * i < slash) {
                            mask = (uint8_t)(0xFFu << (8 * i + 8 - slash));
                        }
                        if ((ip & mask) != net) {
                            return 0;
                        }
                    }
                    return 1;
                }
            }
        }
    }
#else
    (void)no_strict;
#endif
 
    /* malformed */
    return -1;
}
 
 
static int
set_throttle(const char *spec, const union usa *rsa, const char *uri)
{
    int throttle = 0;
    struct vec vec, val;
    char mult;
    double v;
 
    while ((spec = next_option(spec, &vec, &val)) != NULL) {
        mult = ',';
        if ((val.ptr == NULL)
            || (sscanf(val.ptr, "%lf%c", &v, &mult)
                < 1) // NOLINT(cert-err34-c) 'sscanf' used to convert a string
                     // to an integer value, but function will not report
                     // conversion errors; consider using 'strtol' instead
            || (v < 0)
            || ((lowercase(&mult) != 'k') && (lowercase(&mult) != 'm')
                && (mult != ','))) {
            continue;
        }
        v *= (lowercase(&mult) == 'k')
                 ? 1024
                 : ((lowercase(&mult) == 'm') ? 1048576 : 1);
        if (vec.len == 1 && vec.ptr[0] == '*') {
            throttle = (int)v;
        } else {
            int matched = parse_match_net(&vec, rsa, 0);
            if (matched >= 0) {
                /* a valid IP subnet */
                if (matched) {
                    throttle = (int)v;
                }
            } else if (match_prefix(vec.ptr, vec.len, uri) > 0) {
                throttle = (int)v;
            }
        }
    }
 
    return throttle;
}
 
 
/* The mg_upload function is superseded by mg_handle_form_request. */
#include "handle_form.inl"
 
 
static int
get_first_ssl_listener_index(const struct mg_context *ctx)
{
    unsigned int i;
    int idx = -1;
    if (ctx) {
        for (i = 0; ((idx == -1) && (i < ctx->num_listening_sockets)); i++) {
            idx = ctx->listening_sockets[i].is_ssl ? ((int)(i)) : -1;
        }
    }
    return idx;
}
 
 
/* Return host (without port) */
static void
get_host_from_request_info(struct vec *host, const struct mg_request_info *ri)
{
    const char *host_header =
        get_header(ri->http_headers, ri->num_headers, "Host");
 
    host->ptr = NULL;
    host->len = 0;
 
    if (host_header != NULL) {
        const char *pos;
 
        /* If the "Host" is an IPv6 address, like [::1], parse until ]
         * is found. */
        if (*host_header == '[') {
            pos = strchr(host_header, ']');
            if (!pos) {
                /* Malformed hostname starts with '[', but no ']' found */
                DEBUG_TRACE("%s", "Host name format error '[' without ']'");
                return;
            }
            /* terminate after ']' */
            host->ptr = host_header;
            host->len = (size_t)(pos + 1 - host_header);
        } else {
            /* Otherwise, a ':' separates hostname and port number */
            pos = strchr(host_header, ':');
            if (pos != NULL) {
                host->len = (size_t)(pos - host_header);
            } else {
                host->len = strlen(host_header);
            }
            host->ptr = host_header;
        }
    }
}
 
 
static int
switch_domain_context(struct mg_connection *conn)
{
    struct vec host;
 
    get_host_from_request_info(&host, &conn->request_info);
 
    if (host.ptr) {
        if (conn->ssl) {
            /* This is a HTTPS connection, maybe we have a hostname
             * from SNI (set in ssl_servername_callback). */
            const char *sslhost = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
            if (sslhost && (conn->dom_ctx != &(conn->phys_ctx->dd))) {
                /* We are not using the default domain */
                if ((strlen(sslhost) != host.len)
                    || mg_strncasecmp(host.ptr, sslhost, host.len)) {
                    /* Mismatch between SNI domain and HTTP domain */
                    DEBUG_TRACE("Host mismatch: SNI: %s, HTTPS: %.*s",
                                sslhost,
                                (int)host.len,
                                host.ptr);
                    return 0;
                }
            }
 
        } else {
            struct mg_domain_context *dom = &(conn->phys_ctx->dd);
            while (dom) {
                const char *domName = dom->config[AUTHENTICATION_DOMAIN];
                size_t domNameLen = strlen(domName);
                if ((domNameLen == host.len)
                    && !mg_strncasecmp(host.ptr, domName, host.len)) {
 
                    /* Found matching domain */
                    DEBUG_TRACE("HTTP domain %s found",
                                dom->config[AUTHENTICATION_DOMAIN]);
 
                    /* TODO: Check if this is a HTTP or HTTPS domain */
                    conn->dom_ctx = dom;
                    break;
                }
                mg_lock_context(conn->phys_ctx);
                dom = dom->next;
                mg_unlock_context(conn->phys_ctx);
            }
        }
 
        DEBUG_TRACE("HTTP%s Host: %.*s",
                    conn->ssl ? "S" : "",
                    (int)host.len,
                    host.ptr);
 
    } else {
        DEBUG_TRACE("HTTP%s Host is not set", conn->ssl ? "S" : "");
        return 1;
    }
 
    return 1;
}
 
 
static void
redirect_to_https_port(struct mg_connection *conn, int port)
{
    char target_url[MG_BUF_LEN];
    int truncated = 0;
    const char *expect_proto =
        (conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET) ? "wss" : "https";
 
    /* Use "308 Permanent Redirect" */
    int redirect_code = 308;
 
    /* In any case, close the current connection */
    conn->must_close = 1;
 
    /* Send host, port, uri and (if it exists) ?query_string */
    if (mg_construct_local_link(
            conn, target_url, sizeof(target_url), expect_proto, port, NULL)
        < 0) {
        truncated = 1;
    } else if (conn->request_info.query_string != NULL) {
        size_t slen1 = strlen(target_url);
        size_t slen2 = strlen(conn->request_info.query_string);
        if ((slen1 + slen2 + 2) < sizeof(target_url)) {
            target_url[slen1] = '?';
            memcpy(target_url + slen1 + 1,
                   conn->request_info.query_string,
                   slen2);
            target_url[slen1 + slen2 + 1] = 0;
        } else {
            truncated = 1;
        }
    }
 
    /* Check overflow in location buffer (will not occur if MG_BUF_LEN
     * is used as buffer size) */
    if (truncated) {
        mg_send_http_error(conn, 500, "%s", "Redirect URL too long");
        return;
    }
 
    /* Use redirect helper function */
    mg_send_http_redirect(conn, target_url, redirect_code);
}
 
 
static void
mg_set_handler_type(struct mg_context *phys_ctx,
                    struct mg_domain_context *dom_ctx,
                    const char *uri,
                    int handler_type,
                    int is_delete_request,
                    mg_request_handler handler,
                    struct mg_websocket_subprotocols *subprotocols,
                    mg_websocket_connect_handler connect_handler,
                    mg_websocket_ready_handler ready_handler,
                    mg_websocket_data_handler data_handler,
                    mg_websocket_close_handler close_handler,
                    mg_authorization_handler auth_handler,
                    void *cbdata)
{
    struct mg_handler_info *tmp_rh, **lastref;
    size_t urilen = strlen(uri);
 
    if (handler_type == WEBSOCKET_HANDLER) {
        DEBUG_ASSERT(handler == NULL);
        DEBUG_ASSERT(is_delete_request || connect_handler != NULL
                     || ready_handler != NULL || data_handler != NULL
                     || close_handler != NULL);
 
        DEBUG_ASSERT(auth_handler == NULL);
        if (handler != NULL) {
            return;
        }
        if (!is_delete_request && (connect_handler == NULL)
            && (ready_handler == NULL) && (data_handler == NULL)
            && (close_handler == NULL)) {
            return;
        }
        if (auth_handler != NULL) {
            return;
        }
 
    } else if (handler_type == REQUEST_HANDLER) {
        DEBUG_ASSERT(connect_handler == NULL && ready_handler == NULL
                     && data_handler == NULL && close_handler == NULL);
        DEBUG_ASSERT(is_delete_request || (handler != NULL));
        DEBUG_ASSERT(auth_handler == NULL);
 
        if ((connect_handler != NULL) || (ready_handler != NULL)
            || (data_handler != NULL) || (close_handler != NULL)) {
            return;
        }
        if (!is_delete_request && (handler == NULL)) {
            return;
        }
        if (auth_handler != NULL) {
            return;
        }
 
    } else if (handler_type == AUTH_HANDLER) {
        DEBUG_ASSERT(handler == NULL);
        DEBUG_ASSERT(connect_handler == NULL && ready_handler == NULL
                     && data_handler == NULL && close_handler == NULL);
        DEBUG_ASSERT(is_delete_request || (auth_handler != NULL));
        if (handler != NULL) {
            return;
        }
        if ((connect_handler != NULL) || (ready_handler != NULL)
            || (data_handler != NULL) || (close_handler != NULL)) {
            return;
        }
        if (!is_delete_request && (auth_handler == NULL)) {
            return;
        }
    } else {
        /* Unknown handler type. */
        return;
    }
 
    if (!phys_ctx || !dom_ctx) {
        /* no context available */
        return;
    }
 
    mg_lock_context(phys_ctx);
 
    /* first try to find an existing handler */
    do {
        lastref = &(dom_ctx->handlers);
        for (tmp_rh = dom_ctx->handlers; tmp_rh != NULL;
             tmp_rh = tmp_rh->next) {
            if (tmp_rh->handler_type == handler_type
                && (urilen == tmp_rh->uri_len) && !strcmp(tmp_rh->uri, uri)) {
                if (!is_delete_request) {
                    /* update existing handler */
                    if (handler_type == REQUEST_HANDLER) {
                        /* Wait for end of use before updating */
                        if (tmp_rh->refcount) {
                            mg_unlock_context(phys_ctx);
                            mg_sleep(1);
                            mg_lock_context(phys_ctx);
                            /* tmp_rh might have been freed, search again. */
                            break;
                        }
                        /* Ok, the handler is no more use -> Update it */
                        tmp_rh->handler = handler;
                    } else if (handler_type == WEBSOCKET_HANDLER) {
                        tmp_rh->subprotocols = subprotocols;
                        tmp_rh->connect_handler = connect_handler;
                        tmp_rh->ready_handler = ready_handler;
                        tmp_rh->data_handler = data_handler;
                        tmp_rh->close_handler = close_handler;
                    } else { /* AUTH_HANDLER */
                        tmp_rh->auth_handler = auth_handler;
                    }
                    tmp_rh->cbdata = cbdata;
                } else {
                    /* remove existing handler */
                    if (handler_type == REQUEST_HANDLER) {
                        /* Wait for end of use before removing */
                        if (tmp_rh->refcount) {
                            tmp_rh->removing = 1;
                            mg_unlock_context(phys_ctx);
                            mg_sleep(1);
                            mg_lock_context(phys_ctx);
                            /* tmp_rh might have been freed, search again. */
                            break;
                        }
                        /* Ok, the handler is no more used */
                    }
                    *lastref = tmp_rh->next;
                    mg_free(tmp_rh->uri);
                    mg_free(tmp_rh);
                }
                mg_unlock_context(phys_ctx);
                return;
            }
            lastref = &(tmp_rh->next);
        }
    } while (tmp_rh != NULL);
 
    if (is_delete_request) {
        /* no handler to set, this was a remove request to a non-existing
         * handler */
        mg_unlock_context(phys_ctx);
        return;
    }
 
    tmp_rh =
        (struct mg_handler_info *)mg_calloc_ctx(1,
                                                sizeof(struct mg_handler_info),
                                                phys_ctx);
    if (tmp_rh == NULL) {
        mg_unlock_context(phys_ctx);
        mg_cry_ctx_internal(phys_ctx,
                            "%s",
                            "Cannot create new request handler struct, OOM");
        return;
    }
    tmp_rh->uri = mg_strdup_ctx(uri, phys_ctx);
    if (!tmp_rh->uri) {
        mg_unlock_context(phys_ctx);
        mg_free(tmp_rh);
        mg_cry_ctx_internal(phys_ctx,
                            "%s",
                            "Cannot create new request handler struct, OOM");
        return;
    }
    tmp_rh->uri_len = urilen;
    if (handler_type == REQUEST_HANDLER) {
        tmp_rh->refcount = 0;
        tmp_rh->removing = 0;
        tmp_rh->handler = handler;
    } else if (handler_type == WEBSOCKET_HANDLER) {
        tmp_rh->subprotocols = subprotocols;
        tmp_rh->connect_handler = connect_handler;
        tmp_rh->ready_handler = ready_handler;
        tmp_rh->data_handler = data_handler;
        tmp_rh->close_handler = close_handler;
    } else { /* AUTH_HANDLER */
        tmp_rh->auth_handler = auth_handler;
    }
    tmp_rh->cbdata = cbdata;
    tmp_rh->handler_type = handler_type;
    tmp_rh->next = NULL;
 
    *lastref = tmp_rh;
    mg_unlock_context(phys_ctx);
}
 
 
CIVETWEB_API void
mg_set_request_handler(struct mg_context *ctx,
                       const char *uri,
                       mg_request_handler handler,
                       void *cbdata)
{
    mg_set_handler_type(ctx,
                        &(ctx->dd),
                        uri,
                        REQUEST_HANDLER,
                        handler == NULL,
                        handler,
                        NULL,
                        NULL,
                        NULL,
                        NULL,
                        NULL,
                        NULL,
                        cbdata);
}
 
 
CIVETWEB_API void
mg_set_websocket_handler(struct mg_context *ctx,
                         const char *uri,
                         mg_websocket_connect_handler connect_handler,
                         mg_websocket_ready_handler ready_handler,
                         mg_websocket_data_handler data_handler,
                         mg_websocket_close_handler close_handler,
                         void *cbdata)
{
    mg_set_websocket_handler_with_subprotocols(ctx,
                                               uri,
                                               NULL,
                                               connect_handler,
                                               ready_handler,
                                               data_handler,
                                               close_handler,
                                               cbdata);
}
 
 
CIVETWEB_API void
mg_set_websocket_handler_with_subprotocols(
    struct mg_context *ctx,
    const char *uri,
    struct mg_websocket_subprotocols *subprotocols,
    mg_websocket_connect_handler connect_handler,
    mg_websocket_ready_handler ready_handler,
    mg_websocket_data_handler data_handler,
    mg_websocket_close_handler close_handler,
    void *cbdata)
{
    int is_delete_request = (connect_handler == NULL) && (ready_handler == NULL)
                            && (data_handler == NULL)
                            && (close_handler == NULL);
    mg_set_handler_type(ctx,
                        &(ctx->dd),
                        uri,
                        WEBSOCKET_HANDLER,
                        is_delete_request,
                        NULL,
                        subprotocols,
                        connect_handler,
                        ready_handler,
                        data_handler,
                        close_handler,
                        NULL,
                        cbdata);
}
 
 
CIVETWEB_API void
mg_set_auth_handler(struct mg_context *ctx,
                    const char *uri,
                    mg_authorization_handler handler,
                    void *cbdata)
{
    mg_set_handler_type(ctx,
                        &(ctx->dd),
                        uri,
                        AUTH_HANDLER,
                        handler == NULL,
                        NULL,
                        NULL,
                        NULL,
                        NULL,
                        NULL,
                        NULL,
                        handler,
                        cbdata);
}
 
 
static int
get_request_handler(struct mg_connection *conn,
                    int handler_type,
                    mg_request_handler *handler,
                    struct mg_websocket_subprotocols **subprotocols,
                    mg_websocket_connect_handler *connect_handler,
                    mg_websocket_ready_handler *ready_handler,
                    mg_websocket_data_handler *data_handler,
                    mg_websocket_close_handler *close_handler,
                    mg_authorization_handler *auth_handler,
                    void **cbdata,
                    struct mg_handler_info **handler_info)
{
    const struct mg_request_info *request_info = mg_get_request_info(conn);
    if (request_info) {
        const char *uri = request_info->local_uri;
        size_t urilen = strlen(uri);
        struct mg_handler_info *tmp_rh;
        int step, matched;
 
        if (!conn || !conn->phys_ctx || !conn->dom_ctx) {
            return 0;
        }
 
        mg_lock_context(conn->phys_ctx);
 
        for (step = 0; step < 3; step++) {
            for (tmp_rh = conn->dom_ctx->handlers; tmp_rh != NULL;
                 tmp_rh = tmp_rh->next) {
                if (tmp_rh->handler_type != handler_type) {
                    continue;
                }
                if (step == 0) {
                    /* first try for an exact match */
                    matched = (tmp_rh->uri_len == urilen)
                              && (strcmp(tmp_rh->uri, uri) == 0);
                } else if (step == 1) {
                    /* next try for a partial match, we will accept
                    uri/something */
                    matched =
                        (tmp_rh->uri_len < urilen)
                        && (uri[tmp_rh->uri_len] == '/')
                        && (memcmp(tmp_rh->uri, uri, tmp_rh->uri_len) == 0);
                } else {
                    /* finally try for pattern match */
                    matched =
                        match_prefix(tmp_rh->uri, tmp_rh->uri_len, uri) > 0;
                }
                if (matched) {
                    if (handler_type == WEBSOCKET_HANDLER) {
                        *subprotocols = tmp_rh->subprotocols;
                        *connect_handler = tmp_rh->connect_handler;
                        *ready_handler = tmp_rh->ready_handler;
                        *data_handler = tmp_rh->data_handler;
                        *close_handler = tmp_rh->close_handler;
                    } else if (handler_type == REQUEST_HANDLER) {
                        if (tmp_rh->removing) {
                            /* Treat as none found */
                            step = 2;
                            break;
                        }
                        *handler = tmp_rh->handler;
                        /* Acquire handler and give it back */
                        tmp_rh->refcount++;
                        *handler_info = tmp_rh;
                    } else { /* AUTH_HANDLER */
                        *auth_handler = tmp_rh->auth_handler;
                    }
                    *cbdata = tmp_rh->cbdata;
                    mg_unlock_context(conn->phys_ctx);
                    return 1;
                }
            }
        }
 
        mg_unlock_context(conn->phys_ctx);
    }
    return 0; /* none found */
}
 
 
/* Check if the script file is in a path, allowed for script files.
 * This can be used if uploading files is possible not only for the server
 * admin, and the upload mechanism does not check the file extension.
 */
static int
is_in_script_path(const struct mg_connection *conn, const char *path)
{
    /* TODO (Feature): Add config value for allowed script path.
     * Default: All allowed. */
    (void)conn;
    (void)path;
    return 1;
}
 
 
#if defined(USE_WEBSOCKET) && defined(MG_EXPERIMENTAL_INTERFACES)
static int
experimental_websocket_client_data_wrapper(struct mg_connection *conn,
                                           int bits,
                                           char *data,
                                           size_t len,
                                           void *cbdata)
{
    struct mg_callbacks *pcallbacks = (struct mg_callbacks *)cbdata;
    if (pcallbacks->websocket_data) {
        return pcallbacks->websocket_data(conn, bits, data, len);
    }
    /* No handler set - assume "OK" */
    return 1;
}
 
 
static void
experimental_websocket_client_close_wrapper(const struct mg_connection *conn,
                                            void *cbdata)
{
    struct mg_callbacks *pcallbacks = (struct mg_callbacks *)cbdata;
    if (pcallbacks->connection_close) {
        pcallbacks->connection_close(conn);
    }
}
#endif
 
 
/* Decrement recount of handler. conn must not be NULL, handler_info may be NULL
 */
static void
release_handler_ref(struct mg_connection *conn,
                    struct mg_handler_info *handler_info)
{
    if (handler_info != NULL) {
        /* Use context lock for ref counter */
        mg_lock_context(conn->phys_ctx);
        handler_info->refcount--;
        mg_unlock_context(conn->phys_ctx);
    }
}
 
 
/* This is the heart of the Civetweb's logic.
 * This function is called when the request is read, parsed and validated,
 * and Civetweb must decide what action to take: serve a file, or
 * a directory, or call embedded function, etcetera. */
static void
handle_request(struct mg_connection *conn)
{
    struct mg_request_info *ri = &conn->request_info;
    char path[UTF8_PATH_MAX];
    int uri_len, ssl_index;
    int is_found = 0, is_script_resource = 0, is_websocket_request = 0,
        is_put_or_delete_request = 0, is_callback_resource = 0,
        is_template_text_file = 0, is_webdav_request = 0;
    int i;
    struct mg_file file = STRUCT_FILE_INITIALIZER;
    mg_request_handler callback_handler = NULL;
    struct mg_handler_info *handler_info = NULL;
    struct mg_websocket_subprotocols *subprotocols;
    mg_websocket_connect_handler ws_connect_handler = NULL;
    mg_websocket_ready_handler ws_ready_handler = NULL;
    mg_websocket_data_handler ws_data_handler = NULL;
    mg_websocket_close_handler ws_close_handler = NULL;
    void *callback_data = NULL;
    mg_authorization_handler auth_handler = NULL;
    void *auth_callback_data = NULL;
    int handler_type;
    time_t curtime = time(NULL);
    char date[64];
    char *tmp;
 
    path[0] = 0;
 
    /* 0. Reset internal state (required for HTTP/2 proxy) */
    conn->request_state = 0;
 
    /* 1. get the request url */
    /* 1.1. split into url and query string */
    if ((conn->request_info.query_string = strchr(ri->request_uri, '?'))
        != NULL) {
        *((char *)conn->request_info.query_string++) = '\0';
    }
 
    /* 1.2. do a https redirect, if required. Do not decode URIs yet. */
    if (!conn->client.is_ssl && conn->client.ssl_redir) {
        ssl_index = get_first_ssl_listener_index(conn->phys_ctx);
        if (ssl_index >= 0) {
            int port = (int)ntohs(USA_IN_PORT_UNSAFE(
                &(conn->phys_ctx->listening_sockets[ssl_index].lsa)));
            redirect_to_https_port(conn, port);
        } else {
            /* A http to https forward port has been specified,
             * but no https port to forward to. */
            mg_send_http_error(conn,
                               503,
                               "%s",
                               "Error: SSL forward not configured properly");
            mg_cry_internal(conn,
                            "%s",
                            "Can not redirect to SSL, no SSL port available");
        }
        return;
    }
    uri_len = (int)strlen(ri->local_uri);
 
    /* 1.3. decode url (if config says so) */
    if (should_decode_url(conn)) {
        url_decode_in_place((char *)ri->local_uri);
    }
 
    /* URL decode the query-string only if explicitly set in the configuration
     */
    if (conn->request_info.query_string) {
        if (should_decode_query_string(conn)) {
            url_decode_in_place((char *)conn->request_info.query_string);
        }
    }
 
    /* 1.4. clean URIs, so a path like allowed_dir/../forbidden_file is not
     * possible. The fact that we cleaned the URI is stored in that the
     * pointer to ri->local_ur and ri->local_uri_raw are now different.
     * ri->local_uri_raw still points to memory allocated in
     * worker_thread_run(). ri->local_uri is private to the request so we
     * don't have to use preallocated memory here. */
    tmp = mg_strdup(ri->local_uri_raw);
    if (!tmp) {
        /* Out of memory. We cannot do anything reasonable here. */
        return;
    }
    remove_dot_segments(tmp);
    ri->local_uri = tmp;
 
    /* step 1. completed, the url is known now */
    DEBUG_TRACE("REQUEST: %s %s", ri->request_method, ri->local_uri);
 
    /* 2. if this ip has limited speed, set it for this connection */
    conn->throttle = set_throttle(conn->dom_ctx->config[THROTTLE],
                                  &conn->client.rsa,
                                  ri->local_uri);
 
    /* 3. call a "handle everything" callback, if registered */
    if (conn->phys_ctx->callbacks.begin_request != NULL) {
        /* Note that since V1.7 the "begin_request" function is called
         * before an authorization check. If an authorization check is
         * required, use a request_handler instead. */
        i = conn->phys_ctx->callbacks.begin_request(conn);
        if (i > 0) {
            /* callback already processed the request. Store the
            return value as a status code for the access log. */
            conn->status_code = i;
            if (!conn->must_close) {
                discard_unread_request_data(conn);
            }
            DEBUG_TRACE("%s", "begin_request handled request");
            return;
        } else if (i == 0) {
            /* civetweb should process the request */
        } else {
            /* unspecified - may change with the next version */
            DEBUG_TRACE("%s", "done (undocumented behavior)");
            return;
        }
    }
 
    /* request not yet handled by a handler or redirect, so the request
     * is processed here */
 
    /* 4. Check for CORS preflight requests and handle them (if configured).
     * https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS
     */
    if (!strcmp(ri->request_method, "OPTIONS")) {
        /* Send a response to CORS preflights only if
         * access_control_allow_methods is not NULL and not an empty string.
         * In this case, scripts can still handle CORS. */
        const char *cors_meth_cfg =
            conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_METHODS];
        const char *cors_orig_cfg =
            conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_ORIGIN];
        const char *cors_origin =
            get_header(ri->http_headers, ri->num_headers, "Origin");
        const char *cors_acrm = get_header(ri->http_headers,
                                           ri->num_headers,
                                           "Access-Control-Request-Method");
 
        /* Todo: check if cors_origin is in cors_orig_cfg.
         * Or, let the client check this. */
 
        if ((cors_meth_cfg != NULL) && (*cors_meth_cfg != 0)
            && (cors_orig_cfg != NULL) && (*cors_orig_cfg != 0)
            && (cors_origin != NULL) && (cors_acrm != NULL)) {
            /* This is a valid CORS preflight, and the server is configured
             * to handle it automatically. */
            const char *cors_acrh =
                get_header(ri->http_headers,
                           ri->num_headers,
                           "Access-Control-Request-Headers");
 
            gmt_time_string(date, sizeof(date), &curtime);
            mg_printf(conn,
                      "HTTP/1.1 200 OK\r\n"
                      "Date: %s\r\n"
                      "Access-Control-Allow-Origin: %s\r\n"
                      "Access-Control-Allow-Methods: %s\r\n"
                      "Content-Length: 0\r\n"
                      "Connection: %s\r\n",
                      date,
                      cors_orig_cfg,
                      ((cors_meth_cfg[0] == '*') ? cors_acrm : cors_meth_cfg),
                      suggest_connection_header(conn));
 
            if (cors_acrh != NULL) {
                /* CORS request is asking for additional headers */
                const char *cors_hdr_cfg =
                    conn->dom_ctx->config[ACCESS_CONTROL_ALLOW_HEADERS];
 
                if ((cors_hdr_cfg != NULL) && (*cors_hdr_cfg != 0)) {
                    /* Allow only if access_control_allow_headers is
                     * not NULL and not an empty string. If this
                     * configuration is set to *, allow everything.
                     * Otherwise this configuration must be a list
                     * of allowed HTTP header names. */
                    mg_printf(conn,
                              "Access-Control-Allow-Headers: %s\r\n",
                              ((cors_hdr_cfg[0] == '*') ? cors_acrh
                                                        : cors_hdr_cfg));
                }
            }
            mg_printf(conn, "Access-Control-Max-Age: 60\r\n");
            mg_printf(conn, "\r\n");
            DEBUG_TRACE("%s", "OPTIONS done");
            return;
        }
    }
 
    /* 5. interpret the url to find out how the request must be handled
     */
    /* 5.1. first test, if the request targets the regular http(s)://
     * protocol namespace or the websocket ws(s):// protocol namespace.
     */
    is_websocket_request = (conn->protocol_type == PROTOCOL_TYPE_WEBSOCKET);
#if defined(USE_WEBSOCKET)
    handler_type = is_websocket_request ? WEBSOCKET_HANDLER : REQUEST_HANDLER;
#else
    handler_type = REQUEST_HANDLER;
#endif /* defined(USE_WEBSOCKET) */
 
    if (is_websocket_request) {
        HTTP1_only;
    }
 
    /* 5.2. check if the request will be handled by a callback */
    if (get_request_handler(conn,
                            handler_type,
                            &callback_handler,
                            &subprotocols,
                            &ws_connect_handler,
                            &ws_ready_handler,
                            &ws_data_handler,
                            &ws_close_handler,
                            NULL,
                            &callback_data,
                            &handler_info)) {
        /* 5.2.1. A callback will handle this request. All requests
         * handled by a callback have to be considered as requests
         * to a script resource. */
        is_callback_resource = 1;
        is_script_resource = 1;
        is_put_or_delete_request = is_put_or_delete_method(conn);
        /* Never handle a C callback according to File WebDav rules,
         * even if it is a webdav method */
        is_webdav_request = 0; /* is_civetweb_webdav_method(conn); */
    } else {
    no_callback_resource:
 
        /* 5.2.2. No callback is responsible for this request. The URI
         * addresses a file based resource (static content or Lua/cgi
         * scripts in the file system). */
        is_callback_resource = 0;
        interpret_uri(conn,
                      path,
                      sizeof(path),
                      &file.stat,
                      &is_found,
                      &is_script_resource,
                      &is_websocket_request,
                      &is_put_or_delete_request,
                      &is_webdav_request,
                      &is_template_text_file);
    }
 
    /* 5.3. A webdav request (PROPFIND/PROPPATCH/LOCK/UNLOCK) */
    if (is_webdav_request) {
        /* TODO: Do we need a config option? */
        const char *webdav_enable = conn->dom_ctx->config[ENABLE_WEBDAV];
        if (webdav_enable[0] != 'y') {
            mg_send_http_error(conn,
                               405,
                               "%s method not allowed",
                               conn->request_info.request_method);
            DEBUG_TRACE("%s", "webdav rejected");
            return;
        }
    }
 
    /* 6. authorization check */
    /* 6.1. a custom authorization handler is installed */
    if (get_request_handler(conn,
                            AUTH_HANDLER,
                            NULL,
                            NULL,
                            NULL,
                            NULL,
                            NULL,
                            NULL,
                            &auth_handler,
                            &auth_callback_data,
                            NULL)) {
        if (!auth_handler(conn, auth_callback_data)) {
 
            /* Callback handler will not be used anymore. Release it */
            release_handler_ref(conn, handler_info);
            DEBUG_TRACE("%s", "auth handler rejected request");
            return;
        }
    } else if (is_put_or_delete_request && !is_script_resource
               && !is_callback_resource) {
        HTTP1_only;
        /* 6.2. this request is a PUT/DELETE to a real file */
        /* 6.2.1. thus, the server must have real files */
#if defined(NO_FILES)
        if (1) {
#else
        if (conn->dom_ctx->config[DOCUMENT_ROOT] == NULL
            || conn->dom_ctx->config[PUT_DELETE_PASSWORDS_FILE] == NULL) {
#endif
            /* This code path will not be called for request handlers */
            DEBUG_ASSERT(handler_info == NULL);
 
            /* This server does not have any real files, thus the
             * PUT/DELETE methods are not valid. */
            mg_send_http_error(conn,
                               405,
                               "%s method not allowed",
                               conn->request_info.request_method);
            DEBUG_TRACE("%s", "all file based put/delete requests rejected");
            return;
        }
 
#if !defined(NO_FILES)
        /* 6.2.2. Check if put authorization for static files is
         * available.
         */
        if (!is_authorized_for_put(conn)) {
            send_authorization_request(conn, NULL);
            DEBUG_TRACE("%s", "file write needs authorization");
            return;
        }
#endif
 
    } else {
        /* 6.3. This is either a OPTIONS, GET, HEAD or POST request,
         * or it is a PUT or DELETE request to a resource that does not
         * correspond to a file. Check authorization. */
        if (!check_authorization(conn, path)) {
            send_authorization_request(conn, NULL);
 
            /* Callback handler will not be used anymore. Release it */
            release_handler_ref(conn, handler_info);
            DEBUG_TRACE("%s", "access authorization required");
            return;
        }
    }
 
    /* request is authorized or does not need authorization */
 
    /* 7. check if there are request handlers for this uri */
    if (is_callback_resource) {
        HTTP1_only;
        if (!is_websocket_request) {
            i = callback_handler(conn, callback_data);
 
            /* Callback handler will not be used anymore. Release it */
            release_handler_ref(conn, handler_info);
 
            if (i > 0) {
                /* Do nothing, callback has served the request. Store
                 * then return value as status code for the log and discard
                 * all data from the client not used by the callback. */
                conn->status_code = i;
                if (!conn->must_close) {
                    discard_unread_request_data(conn);
                }
            } else {
                /* The handler did NOT handle the request. */
                /* Some proper reactions would be:
                 * a) close the connections without sending anything
                 * b) send a 404 not found
                 * c) try if there is a file matching the URI
                 * It would be possible to do a, b or c in the callback
                 * implementation, and return 1 - we cannot do anything
                 * here, that is not possible in the callback.
                 *
                 * TODO: What would be the best reaction here?
                 * (Note: The reaction may change, if there is a better
                 * idea.)
                 */
 
                /* For the moment, use option c: We look for a proper file,
                 * but since a file request is not always a script resource,
                 * the authorization check might be different. */
                callback_handler = NULL;
 
                /* Here we are at a dead end:
                 * According to URI matching, a callback should be
                 * responsible for handling the request,
                 * we called it, but the callback declared itself
                 * not responsible.
                 * We use a goto here, to get out of this dead end,
                 * and continue with the default handling.
                 * A goto here is simpler and better to understand
                 * than some curious loop. */
                goto no_callback_resource;
            }
        } else {
#if defined(USE_WEBSOCKET)
            handle_websocket_request(conn,
                                     path,
                                     is_callback_resource,
                                     subprotocols,
                                     ws_connect_handler,
                                     ws_ready_handler,
                                     ws_data_handler,
                                     ws_close_handler,
                                     callback_data);
#endif
        }
        DEBUG_TRACE("%s", "websocket handling done");
        return;
    }
 
    /* 8. handle websocket requests */
#if defined(USE_WEBSOCKET)
    if (is_websocket_request) {
        HTTP1_only;
        if (is_script_resource) {
 
            if (is_in_script_path(conn, path)) {
                /* Websocket Lua script */
                handle_websocket_request(conn,
                                         path,
                                         0 /* Lua Script */,
                                         NULL,
                                         NULL,
                                         NULL,
                                         NULL,
                                         NULL,
                                         conn->phys_ctx->user_data);
            } else {
                /* Script was in an illegal path */
                mg_send_http_error(conn, 403, "%s", "Forbidden");
            }
        } else {
            mg_send_http_error(conn, 404, "%s", "Not found");
        }
        DEBUG_TRACE("%s", "websocket script done");
        return;
    } else
#endif
 
#if defined(NO_FILES)
        /* 9a. In case the server uses only callbacks, this uri is
         * unknown.
         * Then, all request handling ends here. */
        mg_send_http_error(conn, 404, "%s", "Not Found");
 
#else
    /* 9b. This request is either for a static file or resource handled
     * by a script file. Thus, a DOCUMENT_ROOT must exist. */
    if (conn->dom_ctx->config[DOCUMENT_ROOT] == NULL) {
        mg_send_http_error(conn, 404, "%s", "Not Found");
        DEBUG_TRACE("%s", "no document root available");
        return;
    }
 
    /* 10. Request is handled by a script */
    if (is_script_resource) {
        HTTP1_only;
        handle_file_based_request(conn, path, &file);
        DEBUG_TRACE("%s", "script handling done");
        return;
    }
 
    /* Request was not handled by a callback or script. It will be
     * handled by a server internal method. */
 
    /* 11. Handle put/delete/mkcol requests */
    if (is_put_or_delete_request) {
        HTTP1_only;
        /* 11.1. PUT method */
        if (!strcmp(ri->request_method, "PUT")) {
            put_file(conn, path);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        /* 11.2. DELETE method */
        if (!strcmp(ri->request_method, "DELETE")) {
            delete_file(conn, path);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        /* 11.3. MKCOL method */
        if (!strcmp(ri->request_method, "MKCOL")) {
            dav_mkcol(conn, path);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        /* 11.4. MOVE method */
        if (!strcmp(ri->request_method, "MOVE")) {
            dav_move_file(conn, path, 0);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        if (!strcmp(ri->request_method, "COPY")) {
            dav_move_file(conn, path, 1);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        /* 11.5. LOCK method */
        if (!strcmp(ri->request_method, "LOCK")) {
            dav_lock_file(conn, path);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        /* 11.6. UNLOCK method */
        if (!strcmp(ri->request_method, "UNLOCK")) {
            dav_unlock_file(conn, path);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        /* 11.7. PROPPATCH method */
        if (!strcmp(ri->request_method, "PROPPATCH")) {
            dav_proppatch(conn, path);
            DEBUG_TRACE("handling %s request to %s done",
                        ri->request_method,
                        path);
            return;
        }
        /* 11.8. Other methods, e.g.: PATCH
         * This method is not supported for static resources,
         * only for scripts (Lua, CGI) and callbacks. */
        mg_send_http_error(conn,
                           405,
                           "%s method not allowed",
                           conn->request_info.request_method);
        DEBUG_TRACE("method %s on %s is not supported",
                    ri->request_method,
                    path);
        return;
    }
 
    /* 11. File does not exist, or it was configured that it should be
     * hidden */
    if (!is_found || (must_hide_file(conn, path))) {
        mg_send_http_error(conn, 404, "%s", "Not found");
        DEBUG_TRACE("handling %s request to %s: file not found",
                    ri->request_method,
                    path);
        return;
    }
 
    /* 12. Directory uris should end with a slash */
    if (file.stat.is_directory && ((uri_len = (int)strlen(ri->local_uri)) > 0)
        && (ri->local_uri[uri_len - 1] != '/')) {
 
        /* Path + server root */
        size_t buflen = UTF8_PATH_MAX * 2 + 2;
        char *new_path;
 
        if (ri->query_string) {
            buflen += strlen(ri->query_string);
        }
        new_path = (char *)mg_malloc_ctx(buflen, conn->phys_ctx);
        if (!new_path) {
            mg_send_http_error(conn, 500, "out or memory");
        } else {
            mg_get_request_link(conn, new_path, buflen - 1);
            strcat(new_path, "/");
            if (ri->query_string) {
                /* Append ? and query string */
                strcat(new_path, "?");
                strcat(new_path, ri->query_string);
            }
            mg_send_http_redirect(conn, new_path, 301);
            mg_free(new_path);
        }
        DEBUG_TRACE("%s request to %s: directory redirection sent",
                    ri->request_method,
                    path);
        return;
    }
 
    /* 13. Handle other methods than GET/HEAD */
    /* 13.1. Handle PROPFIND */
    if (!strcmp(ri->request_method, "PROPFIND")) {
        handle_propfind(conn, path, &file.stat);
        DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
        return;
    }
    /* 13.2. Handle OPTIONS for files */
    if (!strcmp(ri->request_method, "OPTIONS")) {
        /* This standard handler is only used for real files.
         * Scripts should support the OPTIONS method themselves, to allow a
         * maximum flexibility.
         * Lua and CGI scripts may fully support CORS this way (including
         * preflights). */
        send_options(conn);
        DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
        return;
    }
    /* 13.3. everything but GET and HEAD (e.g. POST) */
    if ((0 != strcmp(ri->request_method, "GET"))
        && (0 != strcmp(ri->request_method, "HEAD"))) {
        mg_send_http_error(conn,
                           405,
                           "%s method not allowed",
                           conn->request_info.request_method);
        DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
        return;
    }
 
    /* 14. directories */
    if (file.stat.is_directory) {
        /* Substitute files have already been handled above. */
        /* Here we can either generate and send a directory listing,
         * or send an "access denied" error. */
        if (!mg_strcasecmp(conn->dom_ctx->config[ENABLE_DIRECTORY_LISTING],
                           "yes")) {
            handle_directory_request(conn, path);
        } else {
            mg_send_http_error(conn,
                               403,
                               "%s",
                               "Error: Directory listing denied");
        }
        DEBUG_TRACE("handling %s request to %s done", ri->request_method, path);
        return;
    }
 
    /* 15. Files with search/replace patterns: LSP and SSI */
    if (is_template_text_file) {
        HTTP1_only;
        handle_file_based_request(conn, path, &file);
        DEBUG_TRACE("handling %s request to %s done (template)",
                    ri->request_method,
                    path);
        return;
    }
 
    /* 16. Static file - maybe cached */
#if !defined(NO_CACHING)
    if ((!conn->in_error_handler) && is_not_modified(conn, &file.stat)) {
        /* Send 304 "Not Modified" - this must not send any body data */
        handle_not_modified_static_file_request(conn, &file);
        DEBUG_TRACE("handling %s request to %s done (not modified)",
                    ri->request_method,
                    path);
        return;
    }
#endif /* !NO_CACHING */
 
    /* 17. Static file - not cached */
    handle_static_file_request(conn, path, &file, NULL, NULL);
    DEBUG_TRACE("handling %s request to %s done (static)",
                ri->request_method,
                path);
 
#endif /* !defined(NO_FILES) */
}
 
 
#if !defined(NO_FILESYSTEMS)
static void
handle_file_based_request(struct mg_connection *conn,
                          const char *path,
                          struct mg_file *file)
{
#if !defined(NO_CGI)
    int cgi_config_idx, inc, max;
#endif
 
    if (!conn || !conn->dom_ctx) {
        return;
    }
 
#if defined(USE_LUA)
    if (match_prefix_strlen(conn->dom_ctx->config[LUA_SERVER_PAGE_EXTENSIONS],
                            path)
        > 0) {
        if (is_in_script_path(conn, path)) {
            /* Lua server page: an SSI like page containing mostly plain
             * html code plus some tags with server generated contents. */
            handle_lsp_request(conn, path, file, NULL);
        } else {
            /* Script was in an illegal path */
            mg_send_http_error(conn, 403, "%s", "Forbidden");
        }
        return;
    }
 
    if (match_prefix_strlen(conn->dom_ctx->config[LUA_SCRIPT_EXTENSIONS], path)
        > 0) {
        if (is_in_script_path(conn, path)) {
            /* Lua in-server module script: a CGI like script used to
             * generate the entire reply. */
            mg_exec_lua_script(conn, path, NULL);
        } else {
            /* Script was in an illegal path */
            mg_send_http_error(conn, 403, "%s", "Forbidden");
        }
        return;
    }
#endif
 
#if defined(USE_DUKTAPE)
    if (match_prefix_strlen(conn->dom_ctx->config[DUKTAPE_SCRIPT_EXTENSIONS],
                            path)
        > 0) {
        if (is_in_script_path(conn, path)) {
            /* Call duktape to generate the page */
            mg_exec_duktape_script(conn, path);
        } else {
            /* Script was in an illegal path */
            mg_send_http_error(conn, 403, "%s", "Forbidden");
        }
        return;
    }
#endif
 
#if !defined(NO_CGI)
    inc = CGI2_EXTENSIONS - CGI_EXTENSIONS;
    max = PUT_DELETE_PASSWORDS_FILE - CGI_EXTENSIONS;
    for (cgi_config_idx = 0; cgi_config_idx < max; cgi_config_idx += inc) {
        if (conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx] != NULL) {
            if (match_prefix_strlen(
                    conn->dom_ctx->config[CGI_EXTENSIONS + cgi_config_idx],
                    path)
                > 0) {
                if (is_in_script_path(conn, path)) {
                    /* CGI scripts may support all HTTP methods */
                    handle_cgi_request(conn, path, cgi_config_idx);
                } else {
                    /* Script was in an illegal path */
                    mg_send_http_error(conn, 403, "%s", "Forbidden");
                }
                return;
            }
        }
    }
#endif /* !NO_CGI */
 
    if (match_prefix_strlen(conn->dom_ctx->config[SSI_EXTENSIONS], path) > 0) {
        if (is_in_script_path(conn, path)) {
            handle_ssi_file_request(conn, path, file);
        } else {
            /* Script was in an illegal path */
            mg_send_http_error(conn, 403, "%s", "Forbidden");
        }
        return;
    }
 
#if !defined(NO_CACHING)
    if ((!conn->in_error_handler) && is_not_modified(conn, &file->stat)) {
        /* Send 304 "Not Modified" - this must not send any body data */
        handle_not_modified_static_file_request(conn, file);
        return;
    }
#endif /* !NO_CACHING */
 
    handle_static_file_request(conn, path, file, NULL, NULL);
}
#endif /* NO_FILESYSTEMS */
 
 
static void
close_all_listening_sockets(struct mg_context *ctx)
{
    unsigned int i;
    if (!ctx) {
        return;
    }
 
    for (i = 0; i < ctx->num_listening_sockets; i++) {
        closesocket(ctx->listening_sockets[i].sock);
#if defined(USE_X_DOM_SOCKET)
        /* For unix domain sockets, the socket name represents a file that has
         * to be deleted. */
        /* See
         * https://stackoverflow.com/questions/15716302/so-reuseaddr-and-af-unix
         */
        if ((ctx->listening_sockets[i].lsa.sin.sin_family == AF_UNIX)
            && (ctx->listening_sockets[i].sock != INVALID_SOCKET)) {
            IGNORE_UNUSED_RESULT(
                remove(ctx->listening_sockets[i].lsa.sun.sun_path));
        }
#endif
        ctx->listening_sockets[i].sock = INVALID_SOCKET;
    }
    mg_free(ctx->listening_sockets);
    ctx->listening_sockets = NULL;
    mg_free(ctx->listening_socket_fds);
    ctx->listening_socket_fds = NULL;
}
 
 
/* Valid listening port specification is: [ip_address:]port[s]
 * Examples for IPv4: 80, 443s, 127.0.0.1:3128, 192.0.2.3:8080s
 * Examples for IPv6: [::]:80, [::1]:80,
 *   [2001:0db8:7654:3210:FEDC:BA98:7654:3210]:443s
 *   see https://tools.ietf.org/html/rfc3513#section-2.2
 * In order to bind to both, IPv4 and IPv6, you can either add
 * both ports using 8080,[::]:8080, or the short form +8080.
 * Both forms differ in detail: 8080,[::]:8080 create two sockets,
 * one only accepting IPv4 the other only IPv6. +8080 creates
 * one socket accepting IPv4 and IPv6. Depending on the IPv6
 * environment, they might work differently, or might not work
 * at all - it must be tested what options work best in the
 * relevant network environment.
 */
static int
parse_port_string(const struct vec *vec, struct socket *so, int *ip_version)
{
    unsigned int a, b, c, d;
    unsigned port;
    unsigned long portUL;
    int ch, len;
    const char *cb;
    char *endptr;
#if defined(USE_IPV6)
    char buf[100] = {0};
#endif
 
    /* MacOS needs that. If we do not zero it, subsequent bind() will fail.
     * Also, all-zeroes in the socket address means binding to all addresses
     * for both IPv4 and IPv6 (INADDR_ANY and IN6ADDR_ANY_INIT). */
    memset(so, 0, sizeof(*so));
    so->lsa.sin.sin_family = AF_INET;
    *ip_version = 0;
 
    /* Initialize len as invalid. */
    port = 0;
    len = 0;
 
    /* Test for different ways to format this string */
    if (sscanf(vec->ptr,
               "%u.%u.%u.%u:%u%n",
               &a,
               &b,
               &c,
               &d,
               &port,
               &len) // NOLINT(cert-err34-c) 'sscanf' used to convert a string
                     // to an integer value, but function will not report
                     // conversion errors; consider using 'strtol' instead
        == 5) {
        /* Bind to a specific IPv4 address, e.g. 192.168.1.5:8080 */
        so->lsa.sin.sin_addr.s_addr =
            htonl((a << 24) | (b << 16) | (c << 8) | d);
        so->lsa.sin.sin_port = htons((uint16_t)port);
        *ip_version = 4;
 
#if defined(USE_IPV6)
    } else if (sscanf(vec->ptr, "[%49[^]]]:%u%n", buf, &port, &len) == 2
               && ((size_t)len <= vec->len)
               && mg_inet_pton(
                      AF_INET6, buf, &so->lsa.sin6, sizeof(so->lsa.sin6), 0)) {
        /* IPv6 address, examples: see above */
        /* so->lsa.sin6.sin6_family = AF_INET6; already set by mg_inet_pton
         */
        so->lsa.sin6.sin6_port = htons((uint16_t)port);
        *ip_version = 6;
#endif
 
    } else if ((vec->ptr[0] == '+')
               && (sscanf(vec->ptr + 1, "%u%n", &port, &len)
                   == 1)) { // NOLINT(cert-err34-c) 'sscanf' used to convert a
                            // string to an integer value, but function will not
                            // report conversion errors; consider using 'strtol'
                            // instead
 
        /* Port is specified with a +, bind to IPv6 and IPv4, INADDR_ANY */
        /* Add 1 to len for the + character we skipped before */
        len++;
 
#if defined(USE_IPV6)
        /* Set socket family to IPv6, do not use IPV6_V6ONLY */
        so->lsa.sin6.sin6_family = AF_INET6;
        so->lsa.sin6.sin6_port = htons((uint16_t)port);
        *ip_version = 4 + 6;
#else
        /* Bind to IPv4 only, since IPv6 is not built in. */
        so->lsa.sin.sin_port = htons((uint16_t)port);
        *ip_version = 4;
#endif
 
    } else if (is_valid_port(portUL = strtoul(vec->ptr, &endptr, 0))
               && (vec->ptr != endptr)) {
        len = (int)(endptr - vec->ptr);
        port = (uint16_t)portUL;
        /* If only port is specified, bind to IPv4, INADDR_ANY */
        so->lsa.sin.sin_port = htons((uint16_t)port);
        *ip_version = 4;
 
    } else if ((cb = strchr(vec->ptr, ':')) != NULL) {
        /* String could be a hostname. This check algorithm
         * will only work for RFC 952 compliant hostnames,
         * starting with a letter, containing only letters,
         * digits and hyphen ('-'). Newer specs may allow
         * more, but this is not guaranteed here, since it
         * may interfere with rules for port option lists. */
 
        /* According to RFC 1035, hostnames are restricted to 255 characters
         * in total (63 between two dots). */
        char hostname[256];
        size_t hostnlen = (size_t)(cb - vec->ptr);
 
        if ((hostnlen >= vec->len) || (hostnlen >= sizeof(hostname))) {
            /* This would be invalid in any case */
            *ip_version = 0;
            return 0;
        }
 
        mg_strlcpy(hostname, vec->ptr, hostnlen + 1);
 
        if (mg_inet_pton(
                AF_INET, hostname, &so->lsa.sin, sizeof(so->lsa.sin), 1)) {
            if (sscanf(cb + 1, "%u%n", &port, &len)
                == 1) { // NOLINT(cert-err34-c) 'sscanf' used to convert a
                        // string to an integer value, but function will not
                        // report conversion errors; consider using 'strtol'
                        // instead
                *ip_version = 4;
                so->lsa.sin.sin_port = htons((uint16_t)port);
                len += (int)(hostnlen + 1);
            } else {
                len = 0;
            }
#if defined(USE_IPV6)
        } else if (mg_inet_pton(AF_INET6,
                                hostname,
                                &so->lsa.sin6,
                                sizeof(so->lsa.sin6),
                                1)) {
            if (sscanf(cb + 1, "%u%n", &port, &len) == 1) {
                *ip_version = 6;
                so->lsa.sin6.sin6_port = htons((uint16_t)port);
                len += (int)(hostnlen + 1);
            } else {
                len = 0;
            }
#endif
        } else {
            len = 0;
        }
 
#if defined(USE_X_DOM_SOCKET)
 
    } else if (vec->ptr[0] == 'x') {
        /* unix (linux) domain socket */
        if (vec->len < sizeof(so->lsa.sun.sun_path)) {
            len = vec->len;
            so->lsa.sun.sun_family = AF_UNIX;
            memset(so->lsa.sun.sun_path, 0, sizeof(so->lsa.sun.sun_path));
            memcpy(so->lsa.sun.sun_path, (char *)vec->ptr + 1, vec->len - 1);
            port = 0;
            *ip_version = 99;
        } else {
            /* String too long */
            len = 0;
        }
#endif
 
    } else {
        /* Parsing failure. */
        len = 0;
    }
 
    /* sscanf and the option splitting code ensure the following condition
     * Make sure the port is valid and vector ends with the port, 's' or 'r' */
    if ((len > 0) && is_valid_port(port)
        && (((size_t)len == vec->len) || (((size_t)len + 1) == vec->len))) {
        /* Next character after the port number */
        ch = ((size_t)len < vec->len) ? vec->ptr[len] : '\0';
        so->is_ssl = (ch == 's');
        so->ssl_redir = (ch == 'r');
        if ((ch == '\0') || (ch == 's') || (ch == 'r')) {
            return 1;
        }
    }
 
    /* Reset ip_version to 0 if there is an error */
    *ip_version = 0;
    return 0;
}
 
 
/* Is there any SSL port in use? */
static int
is_ssl_port_used(const char *ports)
{
    if (ports) {
        /* There are several different allowed syntax variants:
         * - "80" for a single port using every network interface
         * - "localhost:80" for a single port using only localhost
         * - "80,localhost:8080" for two ports, one bound to localhost
         * - "80,127.0.0.1:8084,[::1]:8086" for three ports, one bound
         *   to IPv4 localhost, one to IPv6 localhost
         * - "+80" use port 80 for IPv4 and IPv6
         * - "+80r,+443s" port 80 (HTTP) is a redirect to port 443 (HTTPS),
         *   for both: IPv4 and IPv4
         * - "+443s,localhost:8080" port 443 (HTTPS) for every interface,
         *   additionally port 8080 bound to localhost connections
         *
         * If we just look for 's' anywhere in the string, "localhost:80"
         * will be detected as SSL (false positive).
         * Looking for 's' after a digit may cause false positives in
         * "my24service:8080".
         * Looking from 's' backward if there are only ':' and numbers
         * before will not work for "24service:8080" (non SSL, port 8080)
         * or "24s" (SSL, port 24).
         *
         * Remark: Initially hostnames were not allowed to start with a
         * digit (according to RFC 952), this was allowed later (RFC 1123,
         * Section 2.1).
         *
         * To get this correct, the entire string must be parsed as a whole,
         * reading it as a list element for element and parsing with an
         * algorithm equivalent to parse_port_string.
         *
         * In fact, we use local interface names here, not arbitrary
         * hostnames, so in most cases the only name will be "localhost".
         *
         * So, for now, we use this simple algorithm, that may still return
         * a false positive in bizarre cases.
         */
        int i;
        int portslen = (int)strlen(ports);
        char prevIsNumber = 0;
 
        for (i = 0; i < portslen; i++) {
            if (prevIsNumber && (ports[i] == 's' || ports[i] == 'r')) {
                return 1;
            }
            if (ports[i] >= '0' && ports[i] <= '9') {
                prevIsNumber = 1;
            } else {
                prevIsNumber = 0;
            }
        }
    }
    return 0;
}
 
 
static int
set_ports_option(struct mg_context *phys_ctx)
{
    const char *list;
    int on = 1;
#if defined(USE_IPV6)
    int off = 0;
#endif
    struct vec vec;
    struct socket so, *ptr;
 
    struct mg_pollfd *pfd;
    union usa usa;
    socklen_t len;
    int ip_version;
 
    int portsTotal = 0;
    int portsOk = 0;
 
    const char *opt_txt;
    long opt_listen_backlog;
 
    if (!phys_ctx) {
        return 0;
    }
 
    memset(&so, 0, sizeof(so));
    memset(&usa, 0, sizeof(usa));
    len = sizeof(usa);
    list = phys_ctx->dd.config[LISTENING_PORTS];
 
    while ((list = next_option(list, &vec, NULL)) != NULL) {
 
        portsTotal++;
 
        if (!parse_port_string(&vec, &so, &ip_version)) {
            mg_cry_ctx_internal(
                phys_ctx,
                "%.*s: invalid port spec (entry %i). Expecting list of: %s",
                (int)vec.len,
                vec.ptr,
                portsTotal,
                "[IP_ADDRESS:]PORT[s|r]");
            continue;
        }
 
#if !defined(NO_SSL)
        if (so.is_ssl && phys_ctx->dd.ssl_ctx == NULL) {
 
            mg_cry_ctx_internal(phys_ctx,
                                "Cannot add SSL socket (entry %i)",
                                portsTotal);
            continue;
        }
#endif
        /* Create socket. */
        /* For a list of protocol numbers (e.g., TCP==6) see:
         * https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
         */
        if ((so.sock =
                 socket(so.lsa.sa.sa_family,
                        SOCK_STREAM,
                        (ip_version == 99) ? (/* LOCAL */ 0) : (/* TCP */ 6)))
            == INVALID_SOCKET) {
 
            mg_cry_ctx_internal(phys_ctx,
                                "cannot create socket (entry %i)",
                                portsTotal);
            continue;
        }
 
#if defined(_WIN32)
        /* Windows SO_REUSEADDR lets many procs binds to a
         * socket, SO_EXCLUSIVEADDRUSE makes the bind fail
         * if someone already has the socket -- DTL */
        /* NOTE: If SO_EXCLUSIVEADDRUSE is used,
         * Windows might need a few seconds before
         * the same port can be used again in the
         * same process, so a short Sleep may be
         * required between mg_stop and mg_start.
         */
        if (setsockopt(so.sock,
                       SOL_SOCKET,
                       SO_EXCLUSIVEADDRUSE,
                       (SOCK_OPT_TYPE)&on,
                       sizeof(on))
            != 0) {
 
            /* Set reuse option, but don't abort on errors. */
            mg_cry_ctx_internal(
                phys_ctx,
                "cannot set socket option SO_EXCLUSIVEADDRUSE (entry %i)",
                portsTotal);
        }
#else
        if (setsockopt(so.sock,
                       SOL_SOCKET,
                       SO_REUSEADDR,
                       (SOCK_OPT_TYPE)&on,
                       sizeof(on))
            != 0) {
 
            /* Set reuse option, but don't abort on errors. */
            mg_cry_ctx_internal(
                phys_ctx,
                "cannot set socket option SO_REUSEADDR (entry %i)",
                portsTotal);
        }
#endif
 
#if defined(USE_X_DOM_SOCKET)
        if (ip_version == 99) {
            /* Unix domain socket */
        } else
#endif
 
            if (ip_version > 4) {
            /* Could be 6 for IPv6 onlyor 10 (4+6) for IPv4+IPv6 */
#if defined(USE_IPV6)
            if (ip_version > 6) {
                if (so.lsa.sa.sa_family == AF_INET6
                    && setsockopt(so.sock,
                                  IPPROTO_IPV6,
                                  IPV6_V6ONLY,
                                  (void *)&off,
                                  sizeof(off))
                           != 0) {
 
                    /* Set IPv6 only option, but don't abort on errors. */
                    mg_cry_ctx_internal(phys_ctx,
                                        "cannot set socket option "
                                        "IPV6_V6ONLY=off (entry %i)",
                                        portsTotal);
                }
            } else {
                if (so.lsa.sa.sa_family == AF_INET6
                    && setsockopt(so.sock,
                                  IPPROTO_IPV6,
                                  IPV6_V6ONLY,
                                  (void *)&on,
                                  sizeof(on))
                           != 0) {
 
                    /* Set IPv6 only option, but don't abort on errors. */
                    mg_cry_ctx_internal(phys_ctx,
                                        "cannot set socket option "
                                        "IPV6_V6ONLY=on (entry %i)",
                                        portsTotal);
                }
            }
#else
            mg_cry_ctx_internal(phys_ctx, "%s", "IPv6 not available");
            closesocket(so.sock);
            so.sock = INVALID_SOCKET;
            continue;
#endif
        }
 
        if (so.lsa.sa.sa_family == AF_INET) {
 
            len = sizeof(so.lsa.sin);
            if (bind(so.sock, &so.lsa.sa, len) != 0) {
                mg_cry_ctx_internal(phys_ctx,
                                    "cannot bind to %.*s: %d (%s)",
                                    (int)vec.len,
                                    vec.ptr,
                                    (int)ERRNO,
                                    strerror(errno));
                closesocket(so.sock);
                so.sock = INVALID_SOCKET;
                continue;
            }
        }
#if defined(USE_IPV6)
        else if (so.lsa.sa.sa_family == AF_INET6) {
 
            len = sizeof(so.lsa.sin6);
            if (bind(so.sock, &so.lsa.sa, len) != 0) {
                mg_cry_ctx_internal(phys_ctx,
                                    "cannot bind to IPv6 %.*s: %d (%s)",
                                    (int)vec.len,
                                    vec.ptr,
                                    (int)ERRNO,
                                    strerror(errno));
                closesocket(so.sock);
                so.sock = INVALID_SOCKET;
                continue;
            }
        }
#endif
#if defined(USE_X_DOM_SOCKET)
        else if (so.lsa.sa.sa_family == AF_UNIX) {
 
            len = sizeof(so.lsa.sun);
            if (bind(so.sock, &so.lsa.sa, len) != 0) {
                mg_cry_ctx_internal(phys_ctx,
                                    "cannot bind to unix socket %s: %d (%s)",
                                    so.lsa.sun.sun_path,
                                    (int)ERRNO,
                                    strerror(errno));
                closesocket(so.sock);
                so.sock = INVALID_SOCKET;
                continue;
            }
        }
#endif
        else {
            mg_cry_ctx_internal(
                phys_ctx,
                "cannot bind: address family not supported (entry %i)",
                portsTotal);
            closesocket(so.sock);
            so.sock = INVALID_SOCKET;
            continue;
        }
 
        opt_txt = phys_ctx->dd.config[LISTEN_BACKLOG_SIZE];
        opt_listen_backlog = strtol(opt_txt, NULL, 10);
        if ((opt_listen_backlog > INT_MAX) || (opt_listen_backlog < 1)) {
            mg_cry_ctx_internal(phys_ctx,
                                "%s value \"%s\" is invalid",
                                config_options[LISTEN_BACKLOG_SIZE].name,
                                opt_txt);
            closesocket(so.sock);
            so.sock = INVALID_SOCKET;
            continue;
        }
 
        if (listen(so.sock, (int)opt_listen_backlog) != 0) {
 
            mg_cry_ctx_internal(phys_ctx,
                                "cannot listen to %.*s: %d (%s)",
                                (int)vec.len,
                                vec.ptr,
                                (int)ERRNO,
                                strerror(errno));
            closesocket(so.sock);
            so.sock = INVALID_SOCKET;
            continue;
        }
 
        if ((getsockname(so.sock, &(usa.sa), &len) != 0)
            || (usa.sa.sa_family != so.lsa.sa.sa_family)) {
 
            int err = (int)ERRNO;
            mg_cry_ctx_internal(phys_ctx,
                                "call to getsockname failed %.*s: %d (%s)",
                                (int)vec.len,
                                vec.ptr,
                                err,
                                strerror(errno));
            closesocket(so.sock);
            so.sock = INVALID_SOCKET;
            continue;
        }
 
        /* Update lsa port in case of random free ports */
#if defined(USE_IPV6)
        if (so.lsa.sa.sa_family == AF_INET6) {
            so.lsa.sin6.sin6_port = usa.sin6.sin6_port;
        } else
#endif
        {
            so.lsa.sin.sin_port = usa.sin.sin_port;
        }
 
        if ((ptr = (struct socket *)
                 mg_realloc_ctx(phys_ctx->listening_sockets,
                                (phys_ctx->num_listening_sockets + 1)
                                    * sizeof(phys_ctx->listening_sockets[0]),
                                phys_ctx))
            == NULL) {
 
            mg_cry_ctx_internal(phys_ctx, "%s", "Out of memory");
            closesocket(so.sock);
            so.sock = INVALID_SOCKET;
            continue;
        }
 
        if ((pfd = (struct mg_pollfd *)
                 mg_realloc_ctx(phys_ctx->listening_socket_fds,
                                (phys_ctx->num_listening_sockets + 1)
                                    * sizeof(phys_ctx->listening_socket_fds[0]),
                                phys_ctx))
            == NULL) {
 
            mg_cry_ctx_internal(phys_ctx, "%s", "Out of memory");
            closesocket(so.sock);
            so.sock = INVALID_SOCKET;
            mg_free(ptr);
            continue;
        }
 
        set_close_on_exec(so.sock, NULL, phys_ctx);
        phys_ctx->listening_sockets = ptr;
        phys_ctx->listening_sockets[phys_ctx->num_listening_sockets] = so;
        phys_ctx->listening_socket_fds = pfd;
        phys_ctx->num_listening_sockets++;
        portsOk++;
    }
 
    if (portsOk != portsTotal) {
        close_all_listening_sockets(phys_ctx);
        portsOk = 0;
    }
 
    return portsOk;
}
 
 
static const char *
header_val(const struct mg_connection *conn, const char *header)
{
    const char *header_value;
 
    if ((header_value = mg_get_header(conn, header)) == NULL) {
        return "-";
    } else {
        return header_value;
    }
}
 
 
#if defined(MG_EXTERNAL_FUNCTION_log_access)
#include "external_log_access.inl"
#elif !defined(NO_FILESYSTEMS)
 
static void
log_access(const struct mg_connection *conn)
{
    const struct mg_request_info *ri;
    struct mg_file fi;
    char date[64], src_addr[IP_ADDR_STR_LEN];
#if defined(REENTRANT_TIME)
    struct tm _tm;
    struct tm *tm = &_tm;
#else
    struct tm *tm;
#endif
 
    const char *referer;
    const char *user_agent;
 
    char log_buf[4096];
 
    if (!conn || !conn->dom_ctx) {
        return;
    }
 
    /* Set log message to "empty" */
    log_buf[0] = 0;
 
#if defined(USE_LUA)
    if (conn->phys_ctx->lua_bg_log_available) {
        int ret;
        struct mg_context *ctx = conn->phys_ctx;
        lua_State *lstate = (lua_State *)ctx->lua_background_state;
        pthread_mutex_lock(&ctx->lua_bg_mutex);
        /* call "log()" in Lua */
        lua_getglobal(lstate, "log");
        prepare_lua_request_info_inner(conn, lstate);
        push_lua_response_log_data(conn, lstate);
 
        ret = lua_pcall(lstate, /* args */ 2, /* results */ 1, 0);
        if (ret == 0) {
            int t = lua_type(lstate, -1);
            if (t == LUA_TBOOLEAN) {
                if (lua_toboolean(lstate, -1) == 0) {
                    /* log() returned false: do not log */
                    pthread_mutex_unlock(&ctx->lua_bg_mutex);
                    return;
                }
                /* log returned true: continue logging */
            } else if (t == LUA_TSTRING) {
                size_t len;
                const char *txt = lua_tolstring(lstate, -1, &len);
                if ((len == 0) || (*txt == 0)) {
                    /* log() returned empty string: do not log */
                    pthread_mutex_unlock(&ctx->lua_bg_mutex);
                    return;
                }
                /* Copy test from Lua into log_buf */
                if (len >= sizeof(log_buf)) {
                    len = sizeof(log_buf) - 1;
                }
                memcpy(log_buf, txt, len);
                log_buf[len] = 0;
            }
        } else {
            lua_cry(conn, ret, lstate, "lua_background_script", "log");
        }
        pthread_mutex_unlock(&ctx->lua_bg_mutex);
    }
#endif
 
    if (conn->dom_ctx->config[ACCESS_LOG_FILE] != NULL) {
        if (mg_fopen(conn,
                     conn->dom_ctx->config[ACCESS_LOG_FILE],
                     MG_FOPEN_MODE_APPEND,
                     &fi)
            == 0) {
            fi.access.fp = NULL;
        }
    } else {
        fi.access.fp = NULL;
    }
 
    /* Log is written to a file and/or a callback. If both are not set,
     * executing the rest of the function is pointless. */
    if ((fi.access.fp == NULL)
        && (conn->phys_ctx->callbacks.log_access == NULL)) {
        return;
    }
 
    /* If we did not get a log message from Lua, create it here. */
    if (!log_buf[0]) {
#if defined(REENTRANT_TIME)
        localtime_r(&conn->conn_birth_time, tm);
#else
        tm = localtime(&conn->conn_birth_time);
#endif
        if (tm != NULL) {
            strftime(date, sizeof(date), "%d/%b/%Y:%H:%M:%S %z", tm);
        } else {
            mg_strlcpy(date, "01/Jan/1970:00:00:00 +0000", sizeof(date));
        }
 
        ri = &conn->request_info;
 
        sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
        referer = header_val(conn, "Referer");
        user_agent = header_val(conn, "User-Agent");
 
        mg_snprintf(conn,
                    NULL, /* Ignore truncation in access log */
                    log_buf,
                    sizeof(log_buf),
                    "%s - %s [%s] \"%s %s%s%s HTTP/%s\" %d %" INT64_FMT
                    " %s %s",
                    src_addr,
                    (ri->remote_user == NULL) ? "-" : ri->remote_user,
                    date,
                    ri->request_method ? ri->request_method : "-",
                    ri->request_uri ? ri->request_uri : "-",
                    ri->query_string ? "?" : "",
                    ri->query_string ? ri->query_string : "",
                    ri->http_version,
                    conn->status_code,
                    conn->num_bytes_sent,
                    referer,
                    user_agent);
    }
 
    /* Here we have a log message in log_buf. Call the callback */
    if (conn->phys_ctx->callbacks.log_access) {
        if (conn->phys_ctx->callbacks.log_access(conn, log_buf)) {
            /* do not log if callback returns non-zero */
            if (fi.access.fp) {
                mg_fclose(&fi.access);
            }
            return;
        }
    }
 
    /* Store in file */
    if (fi.access.fp) {
        int ok = 1;
        flockfile(fi.access.fp);
        if (fprintf(fi.access.fp, "%s\n", log_buf) < 1) {
            ok = 0;
        }
        if (fflush(fi.access.fp) != 0) {
            ok = 0;
        }
        funlockfile(fi.access.fp);
        if (mg_fclose(&fi.access) != 0) {
            ok = 0;
        }
        if (!ok) {
            mg_cry_internal(conn,
                            "Error writing log file %s",
                            conn->dom_ctx->config[ACCESS_LOG_FILE]);
        }
    }
}
#else
#error "Either enable filesystems or provide a custom log_access implementation"
#endif /* Externally provided function */
 
 
/* Verify given socket address against the ACL.
 * Return -1 if ACL is malformed, 0 if address is disallowed, 1 if allowed.
 */
static int
check_acl(struct mg_context *phys_ctx, const union usa *sa)
{
    int allowed, flag, matched;
    struct vec vec;
 
    if (phys_ctx) {
        const char *list = phys_ctx->dd.config[ACCESS_CONTROL_LIST];
 
        /* If any ACL is set, deny by default */
        allowed = (list == NULL) ? '+' : '-';
 
        while ((list = next_option(list, &vec, NULL)) != NULL) {
            flag = vec.ptr[0];
            matched = -1;
            if ((vec.len > 0) && ((flag == '+') || (flag == '-'))) {
                vec.ptr++;
                vec.len--;
                matched = parse_match_net(&vec, sa, 1);
            }
            if (matched < 0) {
                mg_cry_ctx_internal(phys_ctx,
                                    "%s: subnet must be [+|-]IP-addr[/x]",
                                    __func__);
                return -1;
            }
            if (matched) {
                allowed = flag;
            }
        }
 
        return allowed == '+';
    }
    return -1;
}
 
 
#if !defined(_WIN32) && !defined(__ZEPHYR__)
static int
set_uid_option(struct mg_context *phys_ctx)
{
    int success = 0;
 
    if (phys_ctx) {
        /* We are currently running as curr_uid. */
        const uid_t curr_uid = getuid();
        /* If set, we want to run as run_as_user. */
        const char *run_as_user = phys_ctx->dd.config[RUN_AS_USER];
        const struct passwd *to_pw = NULL;
 
        if ((run_as_user != NULL) && (to_pw = getpwnam(run_as_user)) == NULL) {
            /* run_as_user does not exist on the system. We can't proceed
             * further. */
            mg_cry_ctx_internal(phys_ctx,
                                "%s: unknown user [%s]",
                                __func__,
                                run_as_user);
        } else if ((run_as_user == NULL) || (curr_uid == to_pw->pw_uid)) {
            /* There was either no request to change user, or we're already
             * running as run_as_user. Nothing else to do.
             */
            success = 1;
        } else {
            /* Valid change request.  */
            if (setgid(to_pw->pw_gid) == -1) {
                mg_cry_ctx_internal(phys_ctx,
                                    "%s: setgid(%s): %s",
                                    __func__,
                                    run_as_user,
                                    strerror(errno));
            } else if (setgroups(0, NULL) == -1) {
                mg_cry_ctx_internal(phys_ctx,
                                    "%s: setgroups(): %s",
                                    __func__,
                                    strerror(errno));
            } else if (setuid(to_pw->pw_uid) == -1) {
                mg_cry_ctx_internal(phys_ctx,
                                    "%s: setuid(%s): %s",
                                    __func__,
                                    run_as_user,
                                    strerror(errno));
            } else {
                success = 1;
            }
        }
    }
 
    return success;
}
#endif /* !_WIN32 */
 
 
static void
tls_dtor(void *key)
{
    struct mg_workerTLS *tls = (struct mg_workerTLS *)key;
    /* key == pthread_getspecific(sTlsKey); */
 
    if (tls) {
        if (tls->is_master == 2) {
            tls->is_master = -3; /* Mark memory as dead */
            mg_free(tls);
        }
    }
    pthread_setspecific(sTlsKey, NULL);
}
 
 
#if defined(USE_MBEDTLS)
/* Check if SSL is required.
 * If so, set up ctx->ssl_ctx pointer. */
static int
mg_sslctx_init(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
    if (!phys_ctx) {
        return 0;
    }
 
    if (!dom_ctx) {
        dom_ctx = &(phys_ctx->dd);
    }
 
    if (!is_ssl_port_used(dom_ctx->config[LISTENING_PORTS])) {
        /* No SSL port is set. No need to setup SSL. */
        return 1;
    }
 
    dom_ctx->ssl_ctx = (SSL_CTX *)mg_calloc(1, sizeof(*dom_ctx->ssl_ctx));
    if (dom_ctx->ssl_ctx == NULL) {
        fprintf(stderr, "ssl_ctx malloc failed\n");
        return 0;
    }
 
    return mbed_sslctx_init(dom_ctx->ssl_ctx, dom_ctx->config[SSL_CERTIFICATE])
                   == 0
               ? 1
               : 0;
}
 
#elif !defined(NO_SSL)
 
static int ssl_use_pem_file(struct mg_context *phys_ctx,
                            struct mg_domain_context *dom_ctx,
                            const char *pem,
                            const char *chain);
static const char *ssl_error(void);
 
 
static int
refresh_trust(struct mg_connection *conn)
{
    struct stat cert_buf;
    int64_t t = 0;
    const char *pem;
    const char *chain;
    int should_verify_peer;
 
    if ((pem = conn->dom_ctx->config[SSL_CERTIFICATE]) == NULL) {
        /* If pem is NULL and conn->phys_ctx->callbacks.init_ssl is not,
         * refresh_trust still can not work. */
        return 0;
    }
    chain = conn->dom_ctx->config[SSL_CERTIFICATE_CHAIN];
    if (chain == NULL) {
        /* pem is not NULL here */
        chain = pem;
    }
    if (*chain == 0) {
        chain = NULL;
    }
 
    if (stat(pem, &cert_buf) != -1) {
        t = (int64_t)cert_buf.st_mtime;
    }
 
    mg_lock_context(conn->phys_ctx);
    if ((t != 0) && (conn->dom_ctx->ssl_cert_last_mtime != t)) {
        conn->dom_ctx->ssl_cert_last_mtime = t;
 
        should_verify_peer = 0;
        if (conn->dom_ctx->config[SSL_DO_VERIFY_PEER] != NULL) {
            if (mg_strcasecmp(conn->dom_ctx->config[SSL_DO_VERIFY_PEER], "yes")
                == 0) {
                should_verify_peer = 1;
            } else if (mg_strcasecmp(conn->dom_ctx->config[SSL_DO_VERIFY_PEER],
                                     "optional")
                       == 0) {
                should_verify_peer = 1;
            }
        }
 
        if (should_verify_peer) {
            char *ca_path = conn->dom_ctx->config[SSL_CA_PATH];
            char *ca_file = conn->dom_ctx->config[SSL_CA_FILE];
            if (SSL_CTX_load_verify_locations(conn->dom_ctx->ssl_ctx,
                                              ca_file,
                                              ca_path)
                != 1) {
                mg_unlock_context(conn->phys_ctx);
                mg_cry_ctx_internal(
                    conn->phys_ctx,
                    "SSL_CTX_load_verify_locations error: %s "
                    "ssl_verify_peer requires setting "
                    "either ssl_ca_path or ssl_ca_file. Is any of them "
                    "present in "
                    "the .conf file?",
                    ssl_error());
                return 0;
            }
        }
 
        if (ssl_use_pem_file(conn->phys_ctx, conn->dom_ctx, pem, chain) == 0) {
            mg_unlock_context(conn->phys_ctx);
            return 0;
        }
    }
    mg_unlock_context(conn->phys_ctx);
 
    return 1;
}
 
#if defined(OPENSSL_API_1_1)
#else
static pthread_mutex_t *ssl_mutexes;
#endif /* OPENSSL_API_1_1 */
 
static int
sslize(struct mg_connection *conn,
       int (*func)(SSL *),
       const struct mg_client_options *client_options)
{
    int ret, err;
    int short_trust;
    unsigned timeout = 1024;
    unsigned i;
 
    if (!conn) {
        return 0;
    }
 
    short_trust =
        (conn->dom_ctx->config[SSL_SHORT_TRUST] != NULL)
        && (mg_strcasecmp(conn->dom_ctx->config[SSL_SHORT_TRUST], "yes") == 0);
 
    if (short_trust) {
        int trust_ret = refresh_trust(conn);
        if (!trust_ret) {
            return trust_ret;
        }
    }
 
    mg_lock_context(conn->phys_ctx);
    conn->ssl = SSL_new(conn->dom_ctx->ssl_ctx);
    mg_unlock_context(conn->phys_ctx);
    if (conn->ssl == NULL) {
        mg_cry_internal(conn, "sslize error: %s", ssl_error());
        OPENSSL_REMOVE_THREAD_STATE();
        return 0;
    }
    SSL_set_app_data(conn->ssl, (char *)conn);
 
    ret = SSL_set_fd(conn->ssl, conn->client.sock);
    if (ret != 1) {
        mg_cry_internal(conn, "sslize error: %s", ssl_error());
        SSL_free(conn->ssl);
        conn->ssl = NULL;
        OPENSSL_REMOVE_THREAD_STATE();
        return 0;
    }
 
    if (client_options) {
        if (client_options->host_name) {
            SSL_set_tlsext_host_name(conn->ssl, client_options->host_name);
        }
    }
 
    /* Reuse the request timeout for the SSL_Accept/SSL_connect timeout  */
    if (conn->dom_ctx->config[REQUEST_TIMEOUT]) {
        /* NOTE: The loop below acts as a back-off, so we can end
         * up sleeping for more (or less) than the REQUEST_TIMEOUT. */
        int to = atoi(conn->dom_ctx->config[REQUEST_TIMEOUT]);
        if (to >= 0) {
            timeout = (unsigned)to;
        }
    }
 
    /* SSL functions may fail and require to be called again:
     * see https://www.openssl.org/docs/manmaster/ssl/SSL_get_error.html
     * Here "func" could be SSL_connect or SSL_accept. */
    for (i = 0; i <= timeout; i += 50) {
        ERR_clear_error();
        /* conn->dom_ctx may be changed here (see ssl_servername_callback) */
        ret = func(conn->ssl);
        if (ret != 1) {
            err = SSL_get_error(conn->ssl, ret);
            if ((err == SSL_ERROR_WANT_CONNECT)
                || (err == SSL_ERROR_WANT_ACCEPT)
                || (err == SSL_ERROR_WANT_READ) || (err == SSL_ERROR_WANT_WRITE)
                || (err == SSL_ERROR_WANT_X509_LOOKUP)) {
                if (!STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)) {
                    /* Don't wait if the server is going to be stopped. */
                    break;
                }
                if (err == SSL_ERROR_WANT_X509_LOOKUP) {
                    /* Simply retry the function call. */
                    mg_sleep(50);
                } else {
                    /* Need to retry the function call "later".
                     * See https://linux.die.net/man/3/ssl_get_error
                     * This is typical for non-blocking sockets. */
                    struct mg_pollfd pfd;
                    int pollres;
                    pfd.fd = conn->client.sock;
                    pfd.events = ((err == SSL_ERROR_WANT_CONNECT)
                                  || (err == SSL_ERROR_WANT_WRITE))
                                     ? POLLOUT
                                     : POLLIN;
                    pollres =
                        mg_poll(&pfd, 1, 50, &(conn->phys_ctx->stop_flag));
                    if (pollres < 0) {
                        /* Break if error occurred (-1)
                         * or server shutdown (-2) */
                        break;
                    }
                }
 
            } else if (err == SSL_ERROR_SYSCALL) {
                /* This is an IO error. Look at errno. */
                mg_cry_internal(conn, "SSL syscall error %i", ERRNO);
                break;
 
            } else {
                /* This is an SSL specific error, e.g. SSL_ERROR_SSL */
                mg_cry_internal(conn, "sslize error: %s", ssl_error());
                break;
            }
 
        } else {
            /* success */
            break;
        }
    }
    ERR_clear_error();
 
    if (ret != 1) {
        SSL_free(conn->ssl);
        conn->ssl = NULL;
        OPENSSL_REMOVE_THREAD_STATE();
        return 0;
    }
 
    return 1;
}
 
 
/* Return OpenSSL error message (from CRYPTO lib) */
static const char *
ssl_error(void)
{
    unsigned long err;
    err = ERR_get_error();
    return ((err == 0) ? "" : ERR_error_string(err, NULL));
}
 
 
static int
hexdump2string(void *mem, int memlen, char *buf, int buflen)
{
    int i;
    const char hexdigit[] = "0123456789abcdef";
 
    if ((memlen <= 0) || (buflen <= 0)) {
        return 0;
    }
    if (buflen < (3 * memlen)) {
        return 0;
    }
 
    for (i = 0; i < memlen; i++) {
        if (i > 0) {
            buf[3 * i - 1] = ' ';
        }
        buf[3 * i] = hexdigit[(((uint8_t *)mem)[i] >> 4) & 0xF];
        buf[3 * i + 1] = hexdigit[((uint8_t *)mem)[i] & 0xF];
    }
    buf[3 * memlen - 1] = 0;
 
    return 1;
}
 
 
static int
ssl_get_client_cert_info(const struct mg_connection *conn,
                         struct mg_client_cert *client_cert)
{
    X509 *cert = SSL_get_peer_certificate(conn->ssl);
    if (cert) {
        char str_buf[1024];
        unsigned char buf[256];
        char *str_serial = NULL;
        unsigned int ulen;
        int ilen;
        unsigned char *tmp_buf;
        unsigned char *tmp_p;
 
        /* Handle to algorithm used for fingerprint */
        const EVP_MD *digest = EVP_get_digestbyname("sha1");
 
        /* Get Subject and issuer */
        X509_NAME *subj = X509_get_subject_name(cert);
        X509_NAME *iss = X509_get_issuer_name(cert);
 
        /* Get serial number */
        ASN1_INTEGER *serial = X509_get_serialNumber(cert);
 
        /* Translate serial number to a hex string */
        BIGNUM *serial_bn = ASN1_INTEGER_to_BN(serial, NULL);
        if (serial_bn) {
            str_serial = BN_bn2hex(serial_bn);
            BN_free(serial_bn);
        }
        client_cert->serial =
            str_serial ? mg_strdup_ctx(str_serial, conn->phys_ctx) : NULL;
 
        /* Translate subject and issuer to a string */
        (void)X509_NAME_oneline(subj, str_buf, (int)sizeof(str_buf));
        client_cert->subject = mg_strdup_ctx(str_buf, conn->phys_ctx);
        (void)X509_NAME_oneline(iss, str_buf, (int)sizeof(str_buf));
        client_cert->issuer = mg_strdup_ctx(str_buf, conn->phys_ctx);
 
        /* Calculate SHA1 fingerprint and store as a hex string */
        ulen = 0;
 
        /* ASN1_digest is deprecated. Do the calculation manually,
         * using EVP_Digest. */
        ilen = i2d_X509(cert, NULL);
        tmp_buf = (ilen > 0)
                      ? (unsigned char *)mg_malloc_ctx((unsigned)ilen + 1,
                                                       conn->phys_ctx)
                      : NULL;
        if (tmp_buf) {
            tmp_p = tmp_buf;
            (void)i2d_X509(cert, &tmp_p);
            if (!EVP_Digest(
                    tmp_buf, (unsigned)ilen, buf, &ulen, digest, NULL)) {
                ulen = 0;
            }
            mg_free(tmp_buf);
        }
 
        if (!hexdump2string(buf, (int)ulen, str_buf, (int)sizeof(str_buf))) {
            *str_buf = 0;
        }
        client_cert->finger = mg_strdup_ctx(str_buf, conn->phys_ctx);
 
        client_cert->peer_cert = (void *)cert;
 
        /* Strings returned from bn_bn2hex must be freed using OPENSSL_free,
         * see https://linux.die.net/man/3/bn_bn2hex */
        OPENSSL_free(str_serial);
        return 1;
    }
    return 0;
}
 
 
#if defined(OPENSSL_API_1_1)
#else
static void
ssl_locking_callback(int mode, int mutex_num, const char *file, int line)
{
    (void)line;
    (void)file;
 
    if (mode & 1) {
        /* 1 is CRYPTO_LOCK */
        (void)pthread_mutex_lock(&ssl_mutexes[mutex_num]);
    } else {
        (void)pthread_mutex_unlock(&ssl_mutexes[mutex_num]);
    }
}
#endif /* OPENSSL_API_1_1 */
 
 
#if !defined(NO_SSL_DL)
/* Load a DLL/Shared Object with a TLS/SSL implementation. */
static void *
load_tls_dll(char *ebuf,
             size_t ebuf_len,
             const char *dll_name,
             struct ssl_func *sw,
             int *feature_missing)
{
    union {
        void *p;
        void (*fp)(void);
    } u;
    void *dll_handle;
    struct ssl_func *fp;
    int ok;
    int truncated = 0;
 
    if ((dll_handle = dlopen(dll_name, RTLD_LAZY)) == NULL) {
        mg_snprintf(NULL,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s: cannot load %s",
                    __func__,
                    dll_name);
        return NULL;
    }
 
    ok = 1;
    for (fp = sw; fp->name != NULL; fp++) {
#if defined(_WIN32)
        /* GetProcAddress() returns pointer to function */
        u.fp = (void (*)(void))dlsym(dll_handle, fp->name);
#else
        /* dlsym() on UNIX returns void *. ISO C forbids casts of data
         * pointers to function pointers. We need to use a union to make a
         * cast. */
        u.p = dlsym(dll_handle, fp->name);
#endif /* _WIN32 */
 
        /* Set pointer (might be NULL) */
        fp->ptr = u.fp;
 
        if (u.fp == NULL) {
            DEBUG_TRACE("Missing function: %s\n", fp->name);
            if (feature_missing) {
                feature_missing[fp->required]++;
            }
            if (fp->required == TLS_Mandatory) {
                /* Mandatory function is missing */
                if (ok) {
                    /* This is the first missing function.
                     * Create a new error message. */
                    mg_snprintf(NULL,
                                &truncated,
                                ebuf,
                                ebuf_len,
                                "%s: %s: cannot find %s",
                                __func__,
                                dll_name,
                                fp->name);
                    ok = 0;
                } else {
                    /* This is yet anothermissing function.
                     * Append existing error message. */
                    size_t cur_len = strlen(ebuf);
                    if (!truncated && ((ebuf_len - cur_len) > 3)) {
                        mg_snprintf(NULL,
                                    &truncated,
                                    ebuf + cur_len,
                                    ebuf_len - cur_len - 3,
                                    ", %s",
                                    fp->name);
                        if (truncated) {
                            /* If truncated, add "..." */
                            strcat(ebuf, "...");
                        }
                    }
                }
            }
        }
    }
 
    if (!ok) {
        (void)dlclose(dll_handle);
        return NULL;
    }
 
    return dll_handle;
}
 
 
static void *ssllib_dll_handle;    /* Store the ssl library handle. */
static void *cryptolib_dll_handle; /* Store the crypto library handle. */
 
#endif /* NO_SSL_DL */
 
 
#if defined(SSL_ALREADY_INITIALIZED)
static volatile ptrdiff_t cryptolib_users =
    1; /* Reference counter for crypto library. */
#else
static volatile ptrdiff_t cryptolib_users =
    0; /* Reference counter for crypto library. */
#endif
 
 
static int
initialize_openssl(char *ebuf, size_t ebuf_len)
{
#if !defined(OPENSSL_API_1_1) && !defined(OPENSSL_API_3_0)
    int i, num_locks;
    size_t size;
#endif
 
    if (ebuf_len > 0) {
        ebuf[0] = 0;
    }
 
#if !defined(NO_SSL_DL)
    if (!cryptolib_dll_handle) {
        memset(tls_feature_missing, 0, sizeof(tls_feature_missing));
        cryptolib_dll_handle = load_tls_dll(
            ebuf, ebuf_len, CRYPTO_LIB, crypto_sw, tls_feature_missing);
        if (!cryptolib_dll_handle) {
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s: error loading library %s",
                        __func__,
                        CRYPTO_LIB);
            DEBUG_TRACE("%s", ebuf);
            return 0;
        }
    }
#endif /* NO_SSL_DL */
 
    if (mg_atomic_inc(&cryptolib_users) > 1) {
        return 1;
    }
 
#if !defined(OPENSSL_API_1_1) && !defined(OPENSSL_API_3_0)
    /* Initialize locking callbacks, needed for thread safety.
     * http://www.openssl.org/support/faq.html#PROG1
     */
    num_locks = CRYPTO_num_locks();
    if (num_locks < 0) {
        num_locks = 0;
    }
    size = sizeof(pthread_mutex_t) * ((size_t)(num_locks));
 
    /* allocate mutex array, if required */
    if (num_locks == 0) {
        /* No mutex array required */
        ssl_mutexes = NULL;
    } else {
        /* Mutex array required - allocate it */
        ssl_mutexes = (pthread_mutex_t *)mg_malloc(size);
 
        /* Check OOM */
        if (ssl_mutexes == NULL) {
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s: cannot allocate mutexes: %s",
                        __func__,
                        ssl_error());
            DEBUG_TRACE("%s", ebuf);
            return 0;
        }
 
        /* initialize mutex array */
        for (i = 0; i < num_locks; i++) {
            if (0 != pthread_mutex_init(&ssl_mutexes[i], &pthread_mutex_attr)) {
                mg_snprintf(NULL,
                            NULL, /* No truncation check for ebuf */
                            ebuf,
                            ebuf_len,
                            "%s: error initializing mutex %i of %i",
                            __func__,
                            i,
                            num_locks);
                DEBUG_TRACE("%s", ebuf);
                mg_free(ssl_mutexes);
                return 0;
            }
        }
    }
 
    CRYPTO_set_locking_callback(&ssl_locking_callback);
    CRYPTO_set_id_callback(&mg_current_thread_id);
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */
 
#if !defined(NO_SSL_DL)
    if (!ssllib_dll_handle) {
        ssllib_dll_handle =
            load_tls_dll(ebuf, ebuf_len, SSL_LIB, ssl_sw, tls_feature_missing);
        if (!ssllib_dll_handle) {
#if !defined(OPENSSL_API_1_1)
            mg_free(ssl_mutexes);
#endif
            DEBUG_TRACE("%s", ebuf);
            return 0;
        }
    }
#endif /* NO_SSL_DL */
 
#if (defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0))                     \
    && !defined(NO_SSL_DL)
    /* Initialize SSL library */
    OPENSSL_init_ssl(0, NULL);
    OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS
                         | OPENSSL_INIT_LOAD_CRYPTO_STRINGS,
                     NULL);
#else
    /* Initialize SSL library */
    SSL_library_init();
    SSL_load_error_strings();
#endif
 
    return 1;
}
 
 
static int
ssl_use_pem_file(struct mg_context *phys_ctx,
                 struct mg_domain_context *dom_ctx,
                 const char *pem,
                 const char *chain)
{
    if (SSL_CTX_use_certificate_file(dom_ctx->ssl_ctx, pem, 1) == 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "%s: cannot open certificate file %s: %s",
                            __func__,
                            pem,
                            ssl_error());
        return 0;
    }
 
    /* could use SSL_CTX_set_default_passwd_cb_userdata */
    if (SSL_CTX_use_PrivateKey_file(dom_ctx->ssl_ctx, pem, 1) == 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "%s: cannot open private key file %s: %s",
                            __func__,
                            pem,
                            ssl_error());
        return 0;
    }
 
    if (SSL_CTX_check_private_key(dom_ctx->ssl_ctx) == 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "%s: certificate and private key do not match: %s",
                            __func__,
                            pem);
        return 0;
    }
 
    /* In contrast to OpenSSL, wolfSSL does not support certificate
     * chain files that contain private keys and certificates in
     * SSL_CTX_use_certificate_chain_file.
     * The CivetWeb-Server used pem-Files that contained both information.
     * In order to make wolfSSL work, it is split in two files.
     * One file that contains key and certificate used by the server and
     * an optional chain file for the ssl stack.
     */
    if (chain) {
        if (SSL_CTX_use_certificate_chain_file(dom_ctx->ssl_ctx, chain) == 0) {
            mg_cry_ctx_internal(phys_ctx,
                                "%s: cannot use certificate chain file %s: %s",
                                __func__,
                                chain,
                                ssl_error());
            return 0;
        }
    }
    return 1;
}
 
 
#if defined(OPENSSL_API_1_1)
static unsigned long
ssl_get_protocol(int version_id)
{
    long unsigned ret = (long unsigned)SSL_OP_ALL;
    if (version_id > 0)
        ret |= SSL_OP_NO_SSLv2;
    if (version_id > 1)
        ret |= SSL_OP_NO_SSLv3;
    if (version_id > 2)
        ret |= SSL_OP_NO_TLSv1;
    if (version_id > 3)
        ret |= SSL_OP_NO_TLSv1_1;
    if (version_id > 4)
        ret |= SSL_OP_NO_TLSv1_2;
#if defined(SSL_OP_NO_TLSv1_3)
    if (version_id > 5)
        ret |= SSL_OP_NO_TLSv1_3;
#endif
    return ret;
}
#else
static long
ssl_get_protocol(int version_id)
{
    unsigned long ret = (unsigned long)SSL_OP_ALL;
    if (version_id > 0)
        ret |= SSL_OP_NO_SSLv2;
    if (version_id > 1)
        ret |= SSL_OP_NO_SSLv3;
    if (version_id > 2)
        ret |= SSL_OP_NO_TLSv1;
    if (version_id > 3)
        ret |= SSL_OP_NO_TLSv1_1;
    if (version_id > 4)
        ret |= SSL_OP_NO_TLSv1_2;
#if defined(SSL_OP_NO_TLSv1_3)
    if (version_id > 5)
        ret |= SSL_OP_NO_TLSv1_3;
#endif
    return (long)ret;
}
#endif /* OPENSSL_API_1_1 */
 
 
/* SSL callback documentation:
 * https://www.openssl.org/docs/man1.1.0/ssl/SSL_set_info_callback.html
 * https://wiki.openssl.org/index.php/Manual:SSL_CTX_set_info_callback(3)
 * https://linux.die.net/man/3/ssl_set_info_callback */
/* Note: There is no "const" for the first argument in the documentation
 * examples, however some (maybe most, but not all) headers of OpenSSL
 * versions / OpenSSL compatibility layers have it. Having a different
 * definition will cause a warning in C and an error in C++. Use "const SSL
 * *", while automatic conversion from "SSL *" works for all compilers,
 * but not other way around */
static void
ssl_info_callback(const SSL *ssl, int what, int ret)
{
    (void)ret;
 
    if (what & SSL_CB_HANDSHAKE_START) {
        SSL_get_app_data(ssl);
    }
    if (what & SSL_CB_HANDSHAKE_DONE) {
        /* TODO: check for openSSL 1.1 */
        //#define SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS 0x0001
        // ssl->s3->flags |= SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS;
    }
}
 
 
static int
ssl_servername_callback(SSL *ssl, int *ad, void *arg)
{
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
#endif /* defined(GCC_DIAGNOSTIC) */
 
    /* We used an aligned pointer in SSL_set_app_data */
    struct mg_connection *conn = (struct mg_connection *)SSL_get_app_data(ssl);
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */
 
    const char *servername = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
 
    (void)ad;
    (void)arg;
 
    if ((conn == NULL) || (conn->phys_ctx == NULL)) {
        DEBUG_ASSERT(0);
        return SSL_TLSEXT_ERR_NOACK;
    }
    conn->dom_ctx = &(conn->phys_ctx->dd);
 
    /* Old clients (Win XP) will not support SNI. Then, there
     * is no server name available in the request - we can
     * only work with the default certificate.
     * Multiple HTTPS hosts on one IP+port are only possible
     * with a certificate containing all alternative names.
     */
    if ((servername == NULL) || (*servername == 0)) {
        DEBUG_TRACE("%s", "SSL connection not supporting SNI");
        mg_lock_context(conn->phys_ctx);
        SSL_set_SSL_CTX(ssl, conn->dom_ctx->ssl_ctx);
        mg_unlock_context(conn->phys_ctx);
        return SSL_TLSEXT_ERR_NOACK;
    }
 
    DEBUG_TRACE("TLS connection to host %s", servername);
 
    while (conn->dom_ctx) {
        if (!mg_strcasecmp(servername,
                           conn->dom_ctx->config[AUTHENTICATION_DOMAIN])) {
            /* Found matching domain */
            DEBUG_TRACE("TLS domain %s found",
                        conn->dom_ctx->config[AUTHENTICATION_DOMAIN]);
            break;
        }
        mg_lock_context(conn->phys_ctx);
        conn->dom_ctx = conn->dom_ctx->next;
        mg_unlock_context(conn->phys_ctx);
    }
 
    if (conn->dom_ctx == NULL) {
        /* Default domain */
        DEBUG_TRACE("TLS default domain %s used",
                    conn->phys_ctx->dd.config[AUTHENTICATION_DOMAIN]);
        conn->dom_ctx = &(conn->phys_ctx->dd);
    }
    mg_lock_context(conn->phys_ctx);
    SSL_set_SSL_CTX(ssl, conn->dom_ctx->ssl_ctx);
    mg_unlock_context(conn->phys_ctx);
    return SSL_TLSEXT_ERR_OK;
}
 
 
#if defined(USE_ALPN)
static const char alpn_proto_list[] = "\x02h2\x08http/1.1\x08http/1.0";
static const char *alpn_proto_order_http1[] = {alpn_proto_list + 3,
                                               alpn_proto_list + 3 + 8,
                                               NULL};
#if defined(USE_HTTP2)
static const char *alpn_proto_order_http2[] = {alpn_proto_list,
                                               alpn_proto_list + 3,
                                               alpn_proto_list + 3 + 8,
                                               NULL};
#endif
 
static int
alpn_select_cb(SSL *ssl,
               const unsigned char **out,
               unsigned char *outlen,
               const unsigned char *in,
               unsigned int inlen,
               void *arg)
{
    struct mg_domain_context *dom_ctx = (struct mg_domain_context *)arg;
    unsigned int i, j, enable_http2 = 0;
    const char **alpn_proto_order = alpn_proto_order_http1;
 
    struct mg_workerTLS *tls =
        (struct mg_workerTLS *)pthread_getspecific(sTlsKey);
 
    (void)ssl;
 
    if (tls == NULL) {
        /* Need to store protocol in Thread Local Storage */
        /* If there is no Thread Local Storage, don't use ALPN */
        return SSL_TLSEXT_ERR_NOACK;
    }
 
#if defined(USE_HTTP2)
    enable_http2 = (0 == strcmp(dom_ctx->config[ENABLE_HTTP2], "yes"));
    if (enable_http2) {
        alpn_proto_order = alpn_proto_order_http2;
    }
#endif
 
    for (j = 0; alpn_proto_order[j] != NULL; j++) {
        /* check all accepted protocols in this order */
        const char *alpn_proto = alpn_proto_order[j];
        /* search input for matching protocol */
        for (i = 0; i < inlen; i++) {
            if (!memcmp(in + i, alpn_proto, (unsigned char)alpn_proto[0])) {
                *out = in + i + 1;
                *outlen = in[i];
                tls->alpn_proto = alpn_proto;
                return SSL_TLSEXT_ERR_OK;
            }
        }
    }
 
    /* Nothing found */
    return SSL_TLSEXT_ERR_NOACK;
}
 
 
static int
next_protos_advertised_cb(SSL *ssl,
                          const unsigned char **data,
                          unsigned int *len,
                          void *arg)
{
    struct mg_domain_context *dom_ctx = (struct mg_domain_context *)arg;
    *data = (const unsigned char *)alpn_proto_list;
    *len = (unsigned int)strlen((const char *)data);
 
    (void)ssl;
    (void)dom_ctx;
 
    return SSL_TLSEXT_ERR_OK;
}
 
 
static int
init_alpn(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
    unsigned int alpn_len = (unsigned int)strlen((char *)alpn_proto_list);
    int ret = SSL_CTX_set_alpn_protos(dom_ctx->ssl_ctx,
                                      (const unsigned char *)alpn_proto_list,
                                      alpn_len);
    if (ret != 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "SSL_CTX_set_alpn_protos error: %s",
                            ssl_error());
    }
 
    SSL_CTX_set_alpn_select_cb(dom_ctx->ssl_ctx,
                               alpn_select_cb,
                               (void *)dom_ctx);
 
    SSL_CTX_set_next_protos_advertised_cb(dom_ctx->ssl_ctx,
                                          next_protos_advertised_cb,
                                          (void *)dom_ctx);
 
    return ret;
}
#endif
 
 
/* Setup SSL CTX as required by CivetWeb */
static int
init_ssl_ctx_impl(struct mg_context *phys_ctx,
                  struct mg_domain_context *dom_ctx,
                  const char *pem,
                  const char *chain)
{
    int callback_ret;
    int should_verify_peer;
    int peer_certificate_optional;
    const char *ca_path;
    const char *ca_file;
    int use_default_verify_paths;
    int verify_depth;
    struct timespec now_mt;
    md5_byte_t ssl_context_id[16];
    md5_state_t md5state;
    int protocol_ver;
    int ssl_cache_timeout;
 
#if (defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0))                     \
    && !defined(NO_SSL_DL)
    if ((dom_ctx->ssl_ctx = SSL_CTX_new(TLS_server_method())) == NULL) {
        mg_cry_ctx_internal(phys_ctx,
                            "SSL_CTX_new (server) error: %s",
                            ssl_error());
        return 0;
    }
#else
    if ((dom_ctx->ssl_ctx = SSL_CTX_new(SSLv23_server_method())) == NULL) {
        mg_cry_ctx_internal(phys_ctx,
                            "SSL_CTX_new (server) error: %s",
                            ssl_error());
        return 0;
    }
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */
 
#if defined(SSL_OP_NO_TLSv1_3)
    SSL_CTX_clear_options(dom_ctx->ssl_ctx,
                          SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1
                              | SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1_2
                              | SSL_OP_NO_TLSv1_3);
#else
    SSL_CTX_clear_options(dom_ctx->ssl_ctx,
                          SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_NO_TLSv1
                              | SSL_OP_NO_TLSv1_1 | SSL_OP_NO_TLSv1_2);
#endif
 
    protocol_ver = atoi(dom_ctx->config[SSL_PROTOCOL_VERSION]);
    SSL_CTX_set_options(dom_ctx->ssl_ctx, ssl_get_protocol(protocol_ver));
    SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_SINGLE_DH_USE);
    SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_CIPHER_SERVER_PREFERENCE);
    SSL_CTX_set_options(dom_ctx->ssl_ctx,
                        SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION);
    SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_NO_COMPRESSION);
 
#if defined(SSL_OP_NO_RENEGOTIATION)
    SSL_CTX_set_options(dom_ctx->ssl_ctx, SSL_OP_NO_RENEGOTIATION);
#endif
 
#if !defined(NO_SSL_DL)
    SSL_CTX_set_ecdh_auto(dom_ctx->ssl_ctx, 1);
#endif /* NO_SSL_DL */
 
    /* In SSL documentation examples callback defined without const
     * specifier 'void (*)(SSL *, int, int)'   See:
     * https://www.openssl.org/docs/man1.0.2/ssl/ssl.html
     * https://www.openssl.org/docs/man1.1.0/ssl/ssl.html
     * But in the source code const SSL is used:
     * 'void (*)(const SSL *, int, int)' See:
     * https://github.com/openssl/openssl/blob/1d97c8435171a7af575f73c526d79e1ef0ee5960/ssl/ssl.h#L1173
     * Problem about wrong documentation described, but not resolved:
     * https://bugs.launchpad.net/ubuntu/+source/openssl/+bug/1147526
     * Wrong const cast ignored on C or can be suppressed by compiler flags.
     * But when compiled with modern C++ compiler, correct const should be
     * provided
     */
    SSL_CTX_set_info_callback(dom_ctx->ssl_ctx, ssl_info_callback);
 
    SSL_CTX_set_tlsext_servername_callback(dom_ctx->ssl_ctx,
                                           ssl_servername_callback);
 
    /* If a callback has been specified, call it. */
    callback_ret = (phys_ctx->callbacks.init_ssl == NULL)
                       ? 0
                       : (phys_ctx->callbacks.init_ssl(dom_ctx->ssl_ctx,
                                                       phys_ctx->user_data));
 
    /* If callback returns 0, civetweb sets up the SSL certificate.
     * If it returns 1, civetweb assumes the callback already did this.
     * If it returns -1, initializing ssl fails. */
    if (callback_ret < 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "SSL callback returned error: %i",
                            callback_ret);
        return 0;
    }
    if (callback_ret > 0) {
        /* Callback did everything. */
        return 1;
    }
 
    /* If a domain callback has been specified, call it. */
    callback_ret = (phys_ctx->callbacks.init_ssl_domain == NULL)
                       ? 0
                       : (phys_ctx->callbacks.init_ssl_domain(
                             dom_ctx->config[AUTHENTICATION_DOMAIN],
                             dom_ctx->ssl_ctx,
                             phys_ctx->user_data));
 
    /* If domain callback returns 0, civetweb sets up the SSL certificate.
     * If it returns 1, civetweb assumes the callback already did this.
     * If it returns -1, initializing ssl fails. */
    if (callback_ret < 0) {
        mg_cry_ctx_internal(phys_ctx,
                            "Domain SSL callback returned error: %i",
                            callback_ret);
        return 0;
    }
    if (callback_ret > 0) {
        /* Domain callback did everything. */
        return 1;
    }
 
    /* Use some combination of start time, domain and port as a SSL
     * context ID. This should be unique on the current machine. */
    md5_init(&md5state);
    clock_gettime(CLOCK_MONOTONIC, &now_mt);
    md5_append(&md5state, (const md5_byte_t *)&now_mt, sizeof(now_mt));
    md5_append(&md5state,
               (const md5_byte_t *)phys_ctx->dd.config[LISTENING_PORTS],
               strlen(phys_ctx->dd.config[LISTENING_PORTS]));
    md5_append(&md5state,
               (const md5_byte_t *)dom_ctx->config[AUTHENTICATION_DOMAIN],
               strlen(dom_ctx->config[AUTHENTICATION_DOMAIN]));
    md5_append(&md5state, (const md5_byte_t *)phys_ctx, sizeof(*phys_ctx));
    md5_append(&md5state, (const md5_byte_t *)dom_ctx, sizeof(*dom_ctx));
    md5_finish(&md5state, ssl_context_id);
 
    SSL_CTX_set_session_id_context(dom_ctx->ssl_ctx,
                                   (unsigned char *)ssl_context_id,
                                   sizeof(ssl_context_id));
 
    if (pem != NULL) {
        if (!ssl_use_pem_file(phys_ctx, dom_ctx, pem, chain)) {
            return 0;
        }
    }
 
    /* Should we support client certificates? */
    /* Default is "no". */
    should_verify_peer = 0;
    peer_certificate_optional = 0;
    if (dom_ctx->config[SSL_DO_VERIFY_PEER] != NULL) {
        if (mg_strcasecmp(dom_ctx->config[SSL_DO_VERIFY_PEER], "yes") == 0) {
            /* Yes, they are mandatory */
            should_verify_peer = 1;
        } else if (mg_strcasecmp(dom_ctx->config[SSL_DO_VERIFY_PEER],
                                 "optional")
                   == 0) {
            /* Yes, they are optional */
            should_verify_peer = 1;
            peer_certificate_optional = 1;
        }
    }
 
    use_default_verify_paths =
        (dom_ctx->config[SSL_DEFAULT_VERIFY_PATHS] != NULL)
        && (mg_strcasecmp(dom_ctx->config[SSL_DEFAULT_VERIFY_PATHS], "yes")
            == 0);
 
    if (should_verify_peer) {
        ca_path = dom_ctx->config[SSL_CA_PATH];
        ca_file = dom_ctx->config[SSL_CA_FILE];
        if (SSL_CTX_load_verify_locations(dom_ctx->ssl_ctx, ca_file, ca_path)
            != 1) {
            mg_cry_ctx_internal(phys_ctx,
                                "SSL_CTX_load_verify_locations error: %s "
                                "ssl_verify_peer requires setting "
                                "either ssl_ca_path or ssl_ca_file. "
                                "Is any of them present in the "
                                ".conf file?",
                                ssl_error());
            return 0;
        }
 
        if (peer_certificate_optional) {
            SSL_CTX_set_verify(dom_ctx->ssl_ctx, SSL_VERIFY_PEER, NULL);
        } else {
            SSL_CTX_set_verify(dom_ctx->ssl_ctx,
                               SSL_VERIFY_PEER
                                   | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
                               NULL);
        }
 
        if (use_default_verify_paths
            && (SSL_CTX_set_default_verify_paths(dom_ctx->ssl_ctx) != 1)) {
            mg_cry_ctx_internal(phys_ctx,
                                "SSL_CTX_set_default_verify_paths error: %s",
                                ssl_error());
            return 0;
        }
 
        if (dom_ctx->config[SSL_VERIFY_DEPTH]) {
            verify_depth = atoi(dom_ctx->config[SSL_VERIFY_DEPTH]);
            SSL_CTX_set_verify_depth(dom_ctx->ssl_ctx, verify_depth);
        }
    }
 
    if (dom_ctx->config[SSL_CIPHER_LIST] != NULL) {
        if (SSL_CTX_set_cipher_list(dom_ctx->ssl_ctx,
                                    dom_ctx->config[SSL_CIPHER_LIST])
            != 1) {
            mg_cry_ctx_internal(phys_ctx,
                                "SSL_CTX_set_cipher_list error: %s",
                                ssl_error());
        }
    }
 
    /* SSL session caching */
    ssl_cache_timeout = ((dom_ctx->config[SSL_CACHE_TIMEOUT] != NULL)
                             ? atoi(dom_ctx->config[SSL_CACHE_TIMEOUT])
                             : 0);
    if (ssl_cache_timeout > 0) {
        SSL_CTX_set_session_cache_mode(dom_ctx->ssl_ctx, SSL_SESS_CACHE_BOTH);
        /* SSL_CTX_sess_set_cache_size(dom_ctx->ssl_ctx, 10000);  ... use
         * default */
        SSL_CTX_set_timeout(dom_ctx->ssl_ctx, (long)ssl_cache_timeout);
    }
 
#if defined(USE_ALPN)
    /* Initialize ALPN only of TLS library (OpenSSL version) supports ALPN */
#if !defined(NO_SSL_DL)
    if (!tls_feature_missing[TLS_ALPN])
#endif
    {
        init_alpn(phys_ctx, dom_ctx);
    }
#endif
 
    return 1;
}
 
 
/* Check if SSL is required.
 * If so, dynamically load SSL library
 * and set up ctx->ssl_ctx pointer. */
static int
init_ssl_ctx(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
    void *ssl_ctx = 0;
    int callback_ret;
    const char *pem;
    const char *chain;
    char ebuf[128];
 
    if (!phys_ctx) {
        return 0;
    }
 
    if (!dom_ctx) {
        dom_ctx = &(phys_ctx->dd);
    }
 
    if (!is_ssl_port_used(dom_ctx->config[LISTENING_PORTS])) {
        /* No SSL port is set. No need to setup SSL. */
        return 1;
    }
 
    /* Check for external SSL_CTX */
    callback_ret =
        (phys_ctx->callbacks.external_ssl_ctx == NULL)
            ? 0
            : (phys_ctx->callbacks.external_ssl_ctx(&ssl_ctx,
                                                    phys_ctx->user_data));
 
    if (callback_ret < 0) {
        /* Callback exists and returns <0: Initializing failed. */
        mg_cry_ctx_internal(phys_ctx,
                            "external_ssl_ctx callback returned error: %i",
                            callback_ret);
        return 0;
    } else if (callback_ret > 0) {
        /* Callback exists and returns >0: Initializing complete,
         * civetweb should not modify the SSL context. */
        dom_ctx->ssl_ctx = (SSL_CTX *)ssl_ctx;
        if (!initialize_openssl(ebuf, sizeof(ebuf))) {
            mg_cry_ctx_internal(phys_ctx, "%s", ebuf);
            return 0;
        }
        return 1;
    }
    /* If the callback does not exist or return 0, civetweb must initialize
     * the SSL context. Handle "domain" callback next. */
 
    /* Check for external domain SSL_CTX callback. */
    callback_ret = (phys_ctx->callbacks.external_ssl_ctx_domain == NULL)
                       ? 0
                       : (phys_ctx->callbacks.external_ssl_ctx_domain(
                             dom_ctx->config[AUTHENTICATION_DOMAIN],
                             &ssl_ctx,
                             phys_ctx->user_data));
 
    if (callback_ret < 0) {
        /* Callback < 0: Error. Abort init. */
        mg_cry_ctx_internal(
            phys_ctx,
            "external_ssl_ctx_domain callback returned error: %i",
            callback_ret);
        return 0;
    } else if (callback_ret > 0) {
        /* Callback > 0: Consider init done. */
        dom_ctx->ssl_ctx = (SSL_CTX *)ssl_ctx;
        if (!initialize_openssl(ebuf, sizeof(ebuf))) {
            mg_cry_ctx_internal(phys_ctx, "%s", ebuf);
            return 0;
        }
        return 1;
    }
    /* else: external_ssl_ctx/external_ssl_ctx_domain do not exist or return
     * 0, CivetWeb should continue initializing SSL */
 
    /* If PEM file is not specified and the init_ssl callbacks
     * are not specified, setup will fail. */
    if (((pem = dom_ctx->config[SSL_CERTIFICATE]) == NULL)
        && (phys_ctx->callbacks.init_ssl == NULL)
        && (phys_ctx->callbacks.init_ssl_domain == NULL)) {
        /* No certificate and no init_ssl callbacks:
         * Essential data to set up TLS is missing.
         */
        mg_cry_ctx_internal(phys_ctx,
                            "Initializing SSL failed: -%s is not set",
                            config_options[SSL_CERTIFICATE].name);
        return 0;
    }
 
    /* If a certificate chain is configured, use it. */
    chain = dom_ctx->config[SSL_CERTIFICATE_CHAIN];
    if (chain == NULL) {
        /* Default: certificate chain in PEM file */
        chain = pem;
    }
    if ((chain != NULL) && (*chain == 0)) {
        /* If the chain is an empty string, don't use it. */
        chain = NULL;
    }
 
    if (!initialize_openssl(ebuf, sizeof(ebuf))) {
        mg_cry_ctx_internal(phys_ctx, "%s", ebuf);
        return 0;
    }
 
    return init_ssl_ctx_impl(phys_ctx, dom_ctx, pem, chain);
}
 
 
static void
uninitialize_openssl(void)
{
#if defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0)
 
    if (mg_atomic_dec(&cryptolib_users) == 0) {
 
        /* Shutdown according to
         * https://wiki.openssl.org/index.php/Library_Initialization#Cleanup
         * http://stackoverflow.com/questions/29845527/how-to-properly-uninitialize-openssl
         */
        CONF_modules_unload(1);
#else
    int i;
 
    if (mg_atomic_dec(&cryptolib_users) == 0) {
 
        /* Shutdown according to
         * https://wiki.openssl.org/index.php/Library_Initialization#Cleanup
         * http://stackoverflow.com/questions/29845527/how-to-properly-uninitialize-openssl
         */
        CRYPTO_set_locking_callback(NULL);
        CRYPTO_set_id_callback(NULL);
        ENGINE_cleanup();
        CONF_modules_unload(1);
        ERR_free_strings();
        EVP_cleanup();
        CRYPTO_cleanup_all_ex_data();
        OPENSSL_REMOVE_THREAD_STATE();
 
        for (i = 0; i < CRYPTO_num_locks(); i++) {
            pthread_mutex_destroy(&ssl_mutexes[i]);
        }
        mg_free(ssl_mutexes);
        ssl_mutexes = NULL;
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */
    }
}
#endif /* !defined(NO_SSL) && !defined(USE_MBEDTLS) */
 
 
#if !defined(NO_FILESYSTEMS)
static int
set_gpass_option(struct mg_context *phys_ctx, struct mg_domain_context *dom_ctx)
{
    if (phys_ctx) {
        struct mg_file file = STRUCT_FILE_INITIALIZER;
        const char *path;
        struct mg_connection fc;
        if (!dom_ctx) {
            dom_ctx = &(phys_ctx->dd);
        }
        path = dom_ctx->config[GLOBAL_PASSWORDS_FILE];
        if ((path != NULL)
            && !mg_stat(fake_connection(&fc, phys_ctx), path, &file.stat)) {
            mg_cry_ctx_internal(phys_ctx,
                                "Cannot open %s: %s",
                                path,
                                strerror(ERRNO));
            return 0;
        }
        return 1;
    }
    return 0;
}
#endif /* NO_FILESYSTEMS */
 
 
static int
set_acl_option(struct mg_context *phys_ctx)
{
    union usa sa;
    memset(&sa, 0, sizeof(sa));
#if defined(USE_IPV6)
    sa.sin6.sin6_family = AF_INET6;
#else
    sa.sin.sin_family = AF_INET;
#endif
    return check_acl(phys_ctx, &sa) != -1;
}
 
 
static void
reset_per_request_attributes(struct mg_connection *conn)
{
    if (!conn) {
        return;
    }
 
    conn->num_bytes_sent = conn->consumed_content = 0;
 
    conn->path_info = NULL;
    conn->status_code = -1;
    conn->content_len = -1;
    conn->is_chunked = 0;
    conn->must_close = 0;
    conn->request_len = 0;
    conn->request_state = 0;
    conn->throttle = 0;
    conn->accept_gzip = 0;
 
    conn->response_info.content_length = conn->request_info.content_length = -1;
    conn->response_info.http_version = conn->request_info.http_version = NULL;
    conn->response_info.num_headers = conn->request_info.num_headers = 0;
    conn->response_info.status_text = NULL;
    conn->response_info.status_code = 0;
 
    conn->request_info.remote_user = NULL;
    conn->request_info.request_method = NULL;
    conn->request_info.request_uri = NULL;
 
    /* Free cleaned local URI (if any) */
    if (conn->request_info.local_uri != conn->request_info.local_uri_raw) {
        mg_free((void *)conn->request_info.local_uri);
        conn->request_info.local_uri = NULL;
    }
    conn->request_info.local_uri = NULL;
 
#if defined(USE_SERVER_STATS)
    conn->processing_time = 0;
#endif
}
 
 
static int
set_tcp_nodelay(const struct socket *so, int nodelay_on)
{
    if ((so->lsa.sa.sa_family == AF_INET)
        || (so->lsa.sa.sa_family == AF_INET6)) {
        /* Only for TCP sockets */
        if (setsockopt(so->sock,
                       IPPROTO_TCP,
                       TCP_NODELAY,
                       (SOCK_OPT_TYPE)&nodelay_on,
                       sizeof(nodelay_on))
            != 0) {
            /* Error */
            return 1;
        }
    }
    /* OK */
    return 0;
}
 
 
#if !defined(__ZEPHYR__)
static void
close_socket_gracefully(struct mg_connection *conn)
{
#if defined(_WIN32)
    char buf[MG_BUF_LEN];
    int n;
#endif
    struct linger linger;
    int error_code = 0;
    int linger_timeout = -2;
    socklen_t opt_len = sizeof(error_code);
 
    if (!conn) {
        return;
    }
 
    /* http://msdn.microsoft.com/en-us/library/ms739165(v=vs.85).aspx:
     * "Note that enabling a nonzero timeout on a nonblocking socket
     * is not recommended.", so set it to blocking now */
    set_blocking_mode(conn->client.sock);
 
    /* Send FIN to the client */
    shutdown(conn->client.sock, SHUTDOWN_WR);
 
#if defined(_WIN32)
    /* Read and discard pending incoming data. If we do not do that and
     * close
     * the socket, the data in the send buffer may be discarded. This
     * behaviour is seen on Windows, when client keeps sending data
     * when server decides to close the connection; then when client
     * does recv() it gets no data back. */
    do {
        n = pull_inner(NULL, conn, buf, sizeof(buf), /* Timeout in s: */ 1.0);
    } while (n > 0);
#endif
 
    if (conn->dom_ctx->config[LINGER_TIMEOUT]) {
        linger_timeout = atoi(conn->dom_ctx->config[LINGER_TIMEOUT]);
    }
 
    /* Set linger option according to configuration */
    if (linger_timeout >= 0) {
        /* Set linger option to avoid socket hanging out after close. This
         * prevent ephemeral port exhaust problem under high QPS. */
        linger.l_onoff = 1;
 
#if defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable : 4244)
#endif
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wconversion"
#endif
        /* Data type of linger structure elements may differ,
         * so we don't know what cast we need here.
         * Disable type conversion warnings. */
 
        linger.l_linger = (linger_timeout + 999) / 1000;
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
 
    } else {
        linger.l_onoff = 0;
        linger.l_linger = 0;
    }
 
    if (linger_timeout < -1) {
        /* Default: don't configure any linger */
    } else if (getsockopt(conn->client.sock,
                          SOL_SOCKET,
                          SO_ERROR,
#if defined(_WIN32) /* WinSock uses different data type here */
                          (char *)&error_code,
#else
                          &error_code,
#endif
                          &opt_len)
               != 0) {
        /* Cannot determine if socket is already closed. This should
         * not occur and never did in a test. Log an error message
         * and continue. */
        mg_cry_internal(conn,
                        "%s: getsockopt(SOL_SOCKET SO_ERROR) failed: %s",
                        __func__,
                        strerror(ERRNO));
#if defined(_WIN32)
    } else if (error_code == WSAECONNRESET) {
#else
    } else if (error_code == ECONNRESET) {
#endif
        /* Socket already closed by client/peer, close socket without linger
         */
    } else {
 
        /* Set linger timeout */
        if (setsockopt(conn->client.sock,
                       SOL_SOCKET,
                       SO_LINGER,
                       (char *)&linger,
                       sizeof(linger))
            != 0) {
            mg_cry_internal(
                conn,
                "%s: setsockopt(SOL_SOCKET SO_LINGER(%i,%i)) failed: %s",
                __func__,
                linger.l_onoff,
                linger.l_linger,
                strerror(ERRNO));
        }
    }
 
    /* Now we know that our FIN is ACK-ed, safe to close */
    closesocket(conn->client.sock);
    conn->client.sock = INVALID_SOCKET;
}
#endif
 
 
static void
close_connection(struct mg_connection *conn)
{
#if defined(USE_SERVER_STATS)
    conn->conn_state = 6; /* to close */
#endif
 
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
    if (conn->lua_websocket_state) {
        lua_websocket_close(conn, conn->lua_websocket_state);
        conn->lua_websocket_state = NULL;
    }
#endif
 
    mg_lock_connection(conn);
 
    /* Set close flag, so keep-alive loops will stop */
    conn->must_close = 1;
 
    /* call the connection_close callback if assigned */
    if (conn->phys_ctx->callbacks.connection_close != NULL) {
        if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
            conn->phys_ctx->callbacks.connection_close(conn);
        }
    }
 
    /* Reset user data, after close callback is called.
     * Do not reuse it. If the user needs a destructor,
     * it must be done in the connection_close callback. */
    mg_set_user_connection_data(conn, NULL);
 
#if defined(USE_SERVER_STATS)
    conn->conn_state = 7; /* closing */
#endif
 
#if defined(USE_MBEDTLS)
    if (conn->ssl != NULL) {
        mbed_ssl_close(conn->ssl);
        conn->ssl = NULL;
    }
#elif !defined(NO_SSL)
    if (conn->ssl != NULL) {
        /* Run SSL_shutdown twice to ensure completely close SSL connection
         */
        SSL_shutdown(conn->ssl);
        SSL_free(conn->ssl);
        OPENSSL_REMOVE_THREAD_STATE();
        conn->ssl = NULL;
    }
#endif
    if (conn->client.sock != INVALID_SOCKET) {
#if defined(__ZEPHYR__)
        closesocket(conn->client.sock);
#else
        close_socket_gracefully(conn);
#endif
        conn->client.sock = INVALID_SOCKET;
    }
 
    /* call the connection_closed callback if assigned */
    if (conn->phys_ctx->callbacks.connection_closed != NULL) {
        if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
            conn->phys_ctx->callbacks.connection_closed(conn);
        }
    }
 
    mg_unlock_connection(conn);
 
#if defined(USE_SERVER_STATS)
    conn->conn_state = 8; /* closed */
#endif
}
 
 
CIVETWEB_API void
mg_close_connection(struct mg_connection *conn)
{
    if ((conn == NULL) || (conn->phys_ctx == NULL)) {
        return;
    }
 
#if defined(USE_WEBSOCKET)
    if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
        if (conn->in_websocket_handling) {
            /* Set close flag, so the server thread can exit. */
            conn->must_close = 1;
            return;
        }
    }
    if (conn->phys_ctx->context_type == CONTEXT_WS_CLIENT) {
 
        unsigned int i;
 
        /* client context: loops must end */
        STOP_FLAG_ASSIGN(&conn->phys_ctx->stop_flag, 1);
        conn->must_close = 1;
 
        /* We need to get the client thread out of the select/recv call
         * here. */
        /* Since we use a sleep quantum of some seconds to check for recv
         * timeouts, we will just wait a few seconds in mg_join_thread. */
 
        /* join worker thread */
        for (i = 0; i < conn->phys_ctx->cfg_worker_threads; i++) {
            mg_join_thread(conn->phys_ctx->worker_threadids[i]);
        }
    }
#endif /* defined(USE_WEBSOCKET) */
 
    close_connection(conn);
 
#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
    if (((conn->phys_ctx->context_type == CONTEXT_HTTP_CLIENT)
         || (conn->phys_ctx->context_type == CONTEXT_WS_CLIENT))
        && (conn->phys_ctx->dd.ssl_ctx != NULL)) {
        SSL_CTX_free(conn->phys_ctx->dd.ssl_ctx);
    }
#endif
 
#if defined(USE_WEBSOCKET)
    if (conn->phys_ctx->context_type == CONTEXT_WS_CLIENT) {
        mg_free(conn->phys_ctx->worker_threadids);
        (void)pthread_mutex_destroy(&conn->mutex);
        mg_free(conn);
    } else if (conn->phys_ctx->context_type == CONTEXT_HTTP_CLIENT) {
        (void)pthread_mutex_destroy(&conn->mutex);
        mg_free(conn);
    }
#else
    if (conn->phys_ctx->context_type == CONTEXT_HTTP_CLIENT) { /* Client */
        (void)pthread_mutex_destroy(&conn->mutex);
        mg_free(conn);
    }
#endif /* defined(USE_WEBSOCKET) */
}
 
 
static struct mg_connection *
mg_connect_client_impl(const struct mg_client_options *client_options,
                       int use_ssl,
                       struct mg_init_data *init,
                       struct mg_error_data *error)
{
    struct mg_connection *conn = NULL;
    SOCKET sock;
    union usa sa;
    struct sockaddr *psa;
    socklen_t len;
 
    unsigned max_req_size =
        (unsigned)atoi(config_options[MAX_REQUEST_SIZE].default_value);
 
    /* Size of structures, aligned to 8 bytes */
    size_t conn_size = ((sizeof(struct mg_connection) + 7) >> 3) << 3;
    size_t ctx_size = ((sizeof(struct mg_context) + 7) >> 3) << 3;
    size_t alloc_size = conn_size + ctx_size + max_req_size;
 
    (void)init; /* TODO: Implement required options */
 
    conn = (struct mg_connection *)mg_calloc(1, alloc_size);
 
    if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_OK;
        error->code_sub = 0;
        if (error->text_buffer_size > 0) {
            error->text[0] = 0;
        }
    }
 
    if (conn == NULL) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub = (unsigned)alloc_size;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "calloc(): %s",
                        strerror(ERRNO));
        }
        return NULL;
    }
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
#endif /* defined(GCC_DIAGNOSTIC) */
    /* conn_size is aligned to 8 bytes */
 
    conn->phys_ctx = (struct mg_context *)(((char *)conn) + conn_size);
 
#if defined(GCC_DIAGNOSTIC)
#pragma GCC diagnostic pop
#endif /* defined(GCC_DIAGNOSTIC) */
 
    conn->buf = (((char *)conn) + conn_size + ctx_size);
    conn->buf_size = (int)max_req_size;
    conn->phys_ctx->context_type = CONTEXT_HTTP_CLIENT;
    conn->dom_ctx = &(conn->phys_ctx->dd);
 
    if (!connect_socket(conn->phys_ctx,
                        client_options->host,
                        client_options->port,
                        use_ssl,
                        error,
                        &sock,
                        &sa)) {
        /* "error" will be set by connect_socket. */
        /* free all memory and return NULL; */
        mg_free(conn);
        return NULL;
    }
 
#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
#if (defined(OPENSSL_API_1_1) || defined(OPENSSL_API_3_0))                     \
    && !defined(NO_SSL_DL)
 
    if (use_ssl
        && (conn->dom_ctx->ssl_ctx = SSL_CTX_new(TLS_client_method()))
               == NULL) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "SSL_CTX_new error: %s",
                        ssl_error());
        }
 
        closesocket(sock);
        mg_free(conn);
        return NULL;
    }
 
#else
 
    if (use_ssl
        && (conn->dom_ctx->ssl_ctx = SSL_CTX_new(SSLv23_client_method()))
               == NULL) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "SSL_CTX_new error: %s",
                        ssl_error());
        }
 
        closesocket(sock);
        mg_free(conn);
        return NULL;
    }
 
#endif /* OPENSSL_API_1_1 || OPENSSL_API_3_0 */
#endif /* NO_SSL */
 
#if defined(USE_IPV6)
    len = (sa.sa.sa_family == AF_INET) ? sizeof(conn->client.rsa.sin)
                                       : sizeof(conn->client.rsa.sin6);
    psa = (sa.sa.sa_family == AF_INET)
              ? (struct sockaddr *)&(conn->client.rsa.sin)
              : (struct sockaddr *)&(conn->client.rsa.sin6);
#else
    len = sizeof(conn->client.rsa.sin);
    psa = (struct sockaddr *)&(conn->client.rsa.sin);
#endif
 
    conn->client.sock = sock;
    conn->client.lsa = sa;
 
    if (getsockname(sock, psa, &len) != 0) {
        mg_cry_internal(conn,
                        "%s: getsockname() failed: %s",
                        __func__,
                        strerror(ERRNO));
    }
 
    conn->client.is_ssl = use_ssl ? 1 : 0;
    if (0 != pthread_mutex_init(&conn->mutex, &pthread_mutex_attr)) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OS_ERROR;
            error->code_sub = (unsigned)ERRNO;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for ebuf */
                        error->text,
                        error->text_buffer_size,
                        "Can not create mutex");
        }
#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
        SSL_CTX_free(conn->dom_ctx->ssl_ctx);
#endif
        closesocket(sock);
        mg_free(conn);
        return NULL;
    }
 
#if !defined(NO_SSL) && !defined(USE_MBEDTLS) // TODO: mbedTLS client
    if (use_ssl) {
        /* TODO: Check ssl_verify_peer and ssl_ca_path here.
         * SSL_CTX_set_verify call is needed to switch off server
         * certificate checking, which is off by default in OpenSSL and
         * on in yaSSL. */
        /* TODO: SSL_CTX_set_verify(conn->dom_ctx,
         * SSL_VERIFY_PEER, verify_ssl_server); */
 
        if (client_options->client_cert) {
            if (!ssl_use_pem_file(conn->phys_ctx,
                                  conn->dom_ctx,
                                  client_options->client_cert,
                                  NULL)) {
                if (error != NULL) {
                    error->code = MG_ERROR_DATA_CODE_TLS_CLIENT_CERT_ERROR;
                    mg_snprintf(NULL,
                                NULL, /* No truncation check for ebuf */
                                error->text,
                                error->text_buffer_size,
                                "Can not use SSL client certificate");
                }
 
                SSL_CTX_free(conn->dom_ctx->ssl_ctx);
                closesocket(sock);
                mg_free(conn);
                return NULL;
            }
        }
 
        if (client_options->server_cert) {
            if (SSL_CTX_load_verify_locations(conn->dom_ctx->ssl_ctx,
                                              client_options->server_cert,
                                              NULL)
                != 1) {
                if (error != NULL) {
                    error->code = MG_ERROR_DATA_CODE_TLS_SERVER_CERT_ERROR;
                    mg_snprintf(NULL,
                                NULL, /* No truncation check for ebuf */
                                error->text,
                                error->text_buffer_size,
                                "SSL_CTX_load_verify_locations error: %s",
                                ssl_error());
                }
                SSL_CTX_free(conn->dom_ctx->ssl_ctx);
                closesocket(sock);
                mg_free(conn);
                return NULL;
            }
            SSL_CTX_set_verify(conn->dom_ctx->ssl_ctx, SSL_VERIFY_PEER, NULL);
        } else {
            SSL_CTX_set_verify(conn->dom_ctx->ssl_ctx, SSL_VERIFY_NONE, NULL);
        }
 
        if (!sslize(conn, SSL_connect, client_options)) {
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_TLS_CONNECT_ERROR;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for ebuf */
                            error->text,
                            error->text_buffer_size,
                            "SSL connection error");
            }
            SSL_CTX_free(conn->dom_ctx->ssl_ctx);
            closesocket(sock);
            mg_free(conn);
            return NULL;
        }
    }
#endif
 
    return conn;
}
 
 
CIVETWEB_API struct mg_connection *
mg_connect_client_secure(const struct mg_client_options *client_options,
                         char *error_buffer,
                         size_t error_buffer_size)
{
    struct mg_init_data init;
    struct mg_error_data error;
 
    memset(&init, 0, sizeof(init));
    memset(&error, 0, sizeof(error));
    error.text_buffer_size = error_buffer_size;
    error.text = error_buffer;
    return mg_connect_client_impl(client_options, 1, &init, &error);
}
 
 
CIVETWEB_API struct mg_connection *
mg_connect_client(const char *host,
                  int port,
                  int use_ssl,
                  char *error_buffer,
                  size_t error_buffer_size)
{
    struct mg_client_options opts;
    struct mg_init_data init;
    struct mg_error_data error;
 
    memset(&init, 0, sizeof(init));
 
    memset(&error, 0, sizeof(error));
    error.text_buffer_size = error_buffer_size;
    error.text = error_buffer;
 
    memset(&opts, 0, sizeof(opts));
    opts.host = host;
    opts.port = port;
    if (use_ssl) {
        opts.host_name = host;
    }
 
    return mg_connect_client_impl(&opts, use_ssl, &init, &error);
}
 
 
#if defined(MG_EXPERIMENTAL_INTERFACES)
CIVETWEB_API struct mg_connection *
mg_connect_client2(const char *host,
                   const char *protocol,
                   int port,
                   const char *path,
                   struct mg_init_data *init,
                   struct mg_error_data *error)
{
    (void)path;
 
    int is_ssl, is_ws;
    /* void *user_data = (init != NULL) ? init->user_data : NULL; -- TODO */
 
    if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_OK;
        error->code_sub = 0;
        if (error->text_buffer_size > 0) {
            *error->text = 0;
        }
    }
 
    if ((host == NULL) || (protocol == NULL)) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "Invalid parameters");
        }
        return NULL;
    }
 
    /* check all known protocols */
    if (!mg_strcasecmp(protocol, "http")) {
        is_ssl = 0;
        is_ws = 0;
    } else if (!mg_strcasecmp(protocol, "https")) {
        is_ssl = 1;
        is_ws = 0;
#if defined(USE_WEBSOCKET)
    } else if (!mg_strcasecmp(protocol, "ws")) {
        is_ssl = 0;
        is_ws = 1;
    } else if (!mg_strcasecmp(protocol, "wss")) {
        is_ssl = 1;
        is_ws = 1;
#endif
    } else {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Protocol %s not supported",
                        protocol);
        }
        return NULL;
    }
 
    /* TODO: The current implementation here just calls the old
     * implementations, without using any new options. This is just a first
     * step to test the new interfaces. */
#if defined(USE_WEBSOCKET)
    if (is_ws) {
        /* TODO: implement all options */
        return mg_connect_websocket_client(
            host,
            port,
            is_ssl,
            ((error != NULL) ? error->text : NULL),
            ((error != NULL) ? error->text_buffer_size : 0),
            (path ? path : ""),
            NULL /* TODO: origin */,
            experimental_websocket_client_data_wrapper,
            experimental_websocket_client_close_wrapper,
            (void *)init->callbacks);
    }
#else
    (void)is_ws;
#endif
 
    /* TODO: all additional options */
    struct mg_client_options opts;
 
    memset(&opts, 0, sizeof(opts));
    opts.host = host;
    opts.port = port;
 
    return mg_connect_client_impl(&opts, is_ssl, init, error);
}
#endif
 
 
static const struct {
    const char *proto;
    size_t proto_len;
    unsigned default_port;
} abs_uri_protocols[] = {{"http://", 7, 80},
                         {"https://", 8, 443},
                         {"ws://", 5, 80},
                         {"wss://", 6, 443},
                         {NULL, 0, 0}};
 
 
/* Check if the uri is valid.
 * return 0 for invalid uri,
 * return 1 for *,
 * return 2 for relative uri,
 * return 3 for absolute uri without port,
 * return 4 for absolute uri with port */
static int
get_uri_type(const char *uri)
{
    int i;
    const char *hostend, *portbegin;
    char *portend;
    unsigned long port;
 
    /* According to the HTTP standard
     * http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2
     * URI can be an asterisk (*) or should start with slash (relative uri),
     * or it should start with the protocol (absolute uri). */
    if ((uri[0] == '*') && (uri[1] == '\0')) {
        /* asterisk */
        return 1;
    }
 
    /* Valid URIs according to RFC 3986
     * (https://www.ietf.org/rfc/rfc3986.txt)
     * must only contain reserved characters :/?#[]@!$&'()*+,;=
     * and unreserved characters A-Z a-z 0-9 and -._~
     * and % encoded symbols.
     */
    for (i = 0; uri[i] != 0; i++) {
        if (uri[i] < 33) {
            /* control characters and spaces are invalid */
            return 0;
        }
        /* Allow everything else here (See #894) */
    }
 
    /* A relative uri starts with a / character */
    if (uri[0] == '/') {
        /* relative uri */
        return 2;
    }
 
    /* It could be an absolute uri: */
    /* This function only checks if the uri is valid, not if it is
     * addressing the current server. So civetweb can also be used
     * as a proxy server. */
    for (i = 0; abs_uri_protocols[i].proto != NULL; i++) {
        if (mg_strncasecmp(uri,
                           abs_uri_protocols[i].proto,
                           abs_uri_protocols[i].proto_len)
            == 0) {
 
            hostend = strchr(uri + abs_uri_protocols[i].proto_len, '/');
            if (!hostend) {
                return 0;
            }
            portbegin = strchr(uri + abs_uri_protocols[i].proto_len, ':');
            if (!portbegin) {
                return 3;
            }
 
            port = strtoul(portbegin + 1, &portend, 10);
            if ((portend != hostend) || (port <= 0) || !is_valid_port(port)) {
                return 0;
            }
 
            return 4;
        }
    }
 
    return 0;
}
 
 
/* Return NULL or the relative uri at the current server */
static const char *
get_rel_url_at_current_server(const char *uri, const struct mg_connection *conn)
{
    const char *server_domain;
    size_t server_domain_len;
    size_t request_domain_len = 0;
    unsigned long port = 0;
    int i, auth_domain_check_enabled;
    const char *hostbegin = NULL;
    const char *hostend = NULL;
    const char *portbegin;
    char *portend;
 
    auth_domain_check_enabled =
        !mg_strcasecmp(conn->dom_ctx->config[ENABLE_AUTH_DOMAIN_CHECK], "yes");
 
    /* DNS is case insensitive, so use case insensitive string compare here
     */
    for (i = 0; abs_uri_protocols[i].proto != NULL; i++) {
        if (mg_strncasecmp(uri,
                           abs_uri_protocols[i].proto,
                           abs_uri_protocols[i].proto_len)
            == 0) {
 
            hostbegin = uri + abs_uri_protocols[i].proto_len;
            hostend = strchr(hostbegin, '/');
            if (!hostend) {
                return 0;
            }
            portbegin = strchr(hostbegin, ':');
            if ((!portbegin) || (portbegin > hostend)) {
                port = abs_uri_protocols[i].default_port;
                request_domain_len = (size_t)(hostend - hostbegin);
            } else {
                port = strtoul(portbegin + 1, &portend, 10);
                if ((portend != hostend) || (port <= 0)
                    || !is_valid_port(port)) {
                    return 0;
                }
                request_domain_len = (size_t)(portbegin - hostbegin);
            }
            /* protocol found, port set */
            break;
        }
    }
 
    if (!port) {
        /* port remains 0 if the protocol is not found */
        return 0;
    }
 
    /* Check if the request is directed to a different server. */
    /* First check if the port is the same. */
    if (ntohs(USA_IN_PORT_UNSAFE(&conn->client.lsa)) != port) {
        /* Request is directed to a different port */
        return 0;
    }
 
    /* Finally check if the server corresponds to the authentication
     * domain of the server (the server domain).
     * Allow full matches (like http://mydomain.com/path/file.ext), and
     * allow subdomain matches (like http://www.mydomain.com/path/file.ext),
     * but do not allow substrings (like
     * http://notmydomain.com/path/file.ext
     * or http://mydomain.com.fake/path/file.ext).
     */
    if (auth_domain_check_enabled) {
        server_domain = conn->dom_ctx->config[AUTHENTICATION_DOMAIN];
        server_domain_len = strlen(server_domain);
        if ((server_domain_len == 0) || (hostbegin == NULL)) {
            return 0;
        }
        if ((request_domain_len == server_domain_len)
            && (!memcmp(server_domain, hostbegin, server_domain_len))) {
            /* Request is directed to this server - full name match. */
        } else {
            if (request_domain_len < (server_domain_len + 2)) {
                /* Request is directed to another server: The server name
                 * is longer than the request name.
                 * Drop this case here to avoid overflows in the
                 * following checks. */
                return 0;
            }
            if (hostbegin[request_domain_len - server_domain_len - 1] != '.') {
                /* Request is directed to another server: It could be a
                 * substring
                 * like notmyserver.com */
                return 0;
            }
            if (0
                != memcmp(server_domain,
                          hostbegin + request_domain_len - server_domain_len,
                          server_domain_len)) {
                /* Request is directed to another server:
                 * The server name is different. */
                return 0;
            }
        }
    }
 
    return hostend;
}
 
 
static int
get_message(struct mg_connection *conn, char *ebuf, size_t ebuf_len, int *err)
{
    if (ebuf_len > 0) {
        ebuf[0] = '\0';
    }
    *err = 0;
 
    reset_per_request_attributes(conn);
 
    if (!conn) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s",
                    "Internal error");
        *err = 500;
        return 0;
    }
 
    /* Set the time the request was received. This value should be used for
     * timeouts. */
    clock_gettime(CLOCK_MONOTONIC, &(conn->req_time));
 
    conn->request_len =
        read_message(NULL, conn, conn->buf, conn->buf_size, &conn->data_len);
    DEBUG_ASSERT(conn->request_len < 0 || conn->data_len >= conn->request_len);
    if ((conn->request_len >= 0) && (conn->data_len < conn->request_len)) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s",
                    "Invalid message size");
        *err = 500;
        return 0;
    }
 
    if ((conn->request_len == 0) && (conn->data_len == conn->buf_size)) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s",
                    "Message too large");
        *err = 413;
        return 0;
    }
 
    if (conn->request_len <= 0) {
        if (conn->data_len > 0) {
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s",
                        "Malformed message");
            *err = 400;
        } else {
            /* Server did not recv anything -> just close the connection */
            conn->must_close = 1;
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s",
                        "No data received");
            *err = 0;
        }
        return 0;
    }
    return 1;
}
 
 
static int
get_request(struct mg_connection *conn, char *ebuf, size_t ebuf_len, int *err)
{
    const char *cl;
 
    conn->connection_type =
        CONNECTION_TYPE_REQUEST; /* request (valid of not) */
 
    if (!get_message(conn, ebuf, ebuf_len, err)) {
        return 0;
    }
 
    if (parse_http_request(conn->buf, conn->buf_size, &conn->request_info)
        <= 0) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s",
                    "Bad request");
        *err = 400;
        return 0;
    }
 
    /* Message is a valid request */
 
    if (!switch_domain_context(conn)) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s",
                    "Bad request: Host mismatch");
        *err = 400;
        return 0;
    }
 
#if USE_ZLIB
    if (((cl = get_header(conn->request_info.http_headers,
                          conn->request_info.num_headers,
                          "Accept-Encoding"))
         != NULL)
        && strstr(cl, "gzip")) {
        conn->accept_gzip = 1;
    }
#endif
    if (((cl = get_header(conn->request_info.http_headers,
                          conn->request_info.num_headers,
                          "Transfer-Encoding"))
         != NULL)
        && mg_strcasecmp(cl, "identity")) {
        if (mg_strcasecmp(cl, "chunked")) {
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s",
                        "Bad request");
            *err = 400;
            return 0;
        }
        conn->is_chunked = 1;
        conn->content_len = 0; /* not yet read */
    } else if ((cl = get_header(conn->request_info.http_headers,
                                conn->request_info.num_headers,
                                "Content-Length"))
               != NULL) {
        /* Request has content length set */
        char *endptr = NULL;
        conn->content_len = strtoll(cl, &endptr, 10);
        if ((endptr == cl) || (conn->content_len < 0)) {
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s",
                        "Bad request");
            *err = 411;
            return 0;
        }
        /* Publish the content length back to the request info. */
        conn->request_info.content_length = conn->content_len;
    } else {
        /* There is no exception, see RFC7230. */
        conn->content_len = 0;
    }
 
    return 1;
}
 
 
/* conn is assumed to be valid in this internal function */
static int
get_response(struct mg_connection *conn, char *ebuf, size_t ebuf_len, int *err)
{
    const char *cl;
 
    conn->connection_type =
        CONNECTION_TYPE_RESPONSE; /* response (valid or not) */
 
    if (!get_message(conn, ebuf, ebuf_len, err)) {
        return 0;
    }
 
    if (parse_http_response(conn->buf, conn->buf_size, &conn->response_info)
        <= 0) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s",
                    "Bad response");
        *err = 400;
        return 0;
    }
 
    /* Message is a valid response */
 
    if (((cl = get_header(conn->response_info.http_headers,
                          conn->response_info.num_headers,
                          "Transfer-Encoding"))
         != NULL)
        && mg_strcasecmp(cl, "identity")) {
        if (mg_strcasecmp(cl, "chunked")) {
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s",
                        "Bad request");
            *err = 400;
            return 0;
        }
        conn->is_chunked = 1;
        conn->content_len = 0; /* not yet read */
    } else if ((cl = get_header(conn->response_info.http_headers,
                                conn->response_info.num_headers,
                                "Content-Length"))
               != NULL) {
        char *endptr = NULL;
        conn->content_len = strtoll(cl, &endptr, 10);
        if ((endptr == cl) || (conn->content_len < 0)) {
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s",
                        "Bad request");
            *err = 411;
            return 0;
        }
        /* Publish the content length back to the response info. */
        conn->response_info.content_length = conn->content_len;
 
        /* TODO: check if it is still used in response_info */
        conn->request_info.content_length = conn->content_len;
 
        /* TODO: we should also consider HEAD method */
        if (conn->response_info.status_code == 304) {
            conn->content_len = 0;
        }
    } else {
        /* TODO: we should also consider HEAD method */
        if (((conn->response_info.status_code >= 100)
             && (conn->response_info.status_code <= 199))
            || (conn->response_info.status_code == 204)
            || (conn->response_info.status_code == 304)) {
            conn->content_len = 0;
        } else {
            conn->content_len = -1; /* unknown content length */
        }
    }
 
    return 1;
}
 
 
CIVETWEB_API int
mg_get_response(struct mg_connection *conn,
                char *ebuf,
                size_t ebuf_len,
                int timeout)
{
    int err, ret;
    char txt[32]; /* will not overflow */
    char *save_timeout;
    char *new_timeout;
 
    if (ebuf_len > 0) {
        ebuf[0] = '\0';
    }
 
    if (!conn) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    ebuf,
                    ebuf_len,
                    "%s",
                    "Parameter error");
        return -1;
    }
 
    /* Reset the previous responses */
    conn->data_len = 0;
 
    /* Implementation of API function for HTTP clients */
    save_timeout = conn->dom_ctx->config[REQUEST_TIMEOUT];
 
    if (timeout >= 0) {
        mg_snprintf(conn, NULL, txt, sizeof(txt), "%i", timeout);
        new_timeout = txt;
    } else {
        new_timeout = NULL;
    }
 
    conn->dom_ctx->config[REQUEST_TIMEOUT] = new_timeout;
    ret = get_response(conn, ebuf, ebuf_len, &err);
    conn->dom_ctx->config[REQUEST_TIMEOUT] = save_timeout;
 
    /* TODO: here, the URI is the http response code */
    conn->request_info.local_uri_raw = conn->request_info.request_uri;
    conn->request_info.local_uri = conn->request_info.local_uri_raw;
 
    /* TODO (mid): Define proper return values - maybe return length?
     * For the first test use <0 for error and >0 for OK */
    return (ret == 0) ? -1 : +1;
}
 
 
CIVETWEB_API struct mg_connection *
mg_download(const char *host,
            int port,
            int use_ssl,
            char *ebuf,
            size_t ebuf_len,
            const char *fmt,
            ...)
{
    struct mg_connection *conn;
    va_list ap;
    int i;
    int reqerr;
 
    if (ebuf_len > 0) {
        ebuf[0] = '\0';
    }
 
    va_start(ap, fmt);
 
    /* open a connection */
    conn = mg_connect_client(host, port, use_ssl, ebuf, ebuf_len);
 
    if (conn != NULL) {
        i = mg_vprintf(conn, fmt, ap);
        if (i <= 0) {
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        ebuf_len,
                        "%s",
                        "Error sending request");
        } else {
            /* make sure the buffer is clear */
            conn->data_len = 0;
            get_response(conn, ebuf, ebuf_len, &reqerr);
 
            /* TODO: here, the URI is the http response code */
            conn->request_info.local_uri = conn->request_info.request_uri;
        }
    }
 
    /* if an error occurred, close the connection */
    if ((ebuf[0] != '\0') && (conn != NULL)) {
        mg_close_connection(conn);
        conn = NULL;
    }
 
    va_end(ap);
    return conn;
}
 
 
struct websocket_client_thread_data {
    struct mg_connection *conn;
    mg_websocket_data_handler data_handler;
    mg_websocket_close_handler close_handler;
    void *callback_data;
};
 
 
#if defined(USE_WEBSOCKET)
#if defined(_WIN32)
static unsigned __stdcall websocket_client_thread(void *data)
#else
static void *
websocket_client_thread(void *data)
#endif
{
    struct websocket_client_thread_data *cdata =
        (struct websocket_client_thread_data *)data;
 
    void *user_thread_ptr = NULL;
 
#if !defined(_WIN32) && !defined(__ZEPHYR__)
    struct sigaction sa;
 
    /* Ignore SIGPIPE */
    memset(&sa, 0, sizeof(sa));
    sa.sa_handler = SIG_IGN;
    sigaction(SIGPIPE, &sa, NULL);
#endif
 
    mg_set_thread_name("ws-clnt");
 
    if (cdata->conn->phys_ctx) {
        if (cdata->conn->phys_ctx->callbacks.init_thread) {
            /* 3 indicates a websocket client thread */
            /* TODO: check if conn->phys_ctx can be set */
            user_thread_ptr = cdata->conn->phys_ctx->callbacks.init_thread(
                cdata->conn->phys_ctx, 3);
        }
    }
 
    read_websocket(cdata->conn, cdata->data_handler, cdata->callback_data);
 
    DEBUG_TRACE("%s", "Websocket client thread exited\n");
 
    if (cdata->close_handler != NULL) {
        cdata->close_handler(cdata->conn, cdata->callback_data);
    }
 
    /* The websocket_client context has only this thread. If it runs out,
    set the stop_flag to 2 (= "stopped"). */
    STOP_FLAG_ASSIGN(&cdata->conn->phys_ctx->stop_flag, 2);
 
    if (cdata->conn->phys_ctx->callbacks.exit_thread) {
        cdata->conn->phys_ctx->callbacks.exit_thread(cdata->conn->phys_ctx,
                                                     3,
                                                     user_thread_ptr);
    }
 
    mg_free((void *)cdata);
 
#if defined(_WIN32)
    return 0;
#else
    return NULL;
#endif
}
#endif
 
 
static struct mg_connection *
mg_connect_websocket_client_impl(const struct mg_client_options *client_options,
                                 int use_ssl,
                                 char *error_buffer,
                                 size_t error_buffer_size,
                                 const char *path,
                                 const char *origin,
                                 const char *extensions,
                                 mg_websocket_data_handler data_func,
                                 mg_websocket_close_handler close_func,
                                 void *user_data)
{
    struct mg_connection *conn = NULL;
 
#if defined(USE_WEBSOCKET)
    struct websocket_client_thread_data *thread_data;
    static const char *magic = "x3JJHMbDL1EzLkh9GBhXDw==";
 
    const char *host = client_options->host;
    int i;
 
    struct mg_init_data init;
    struct mg_error_data error;
 
    memset(&init, 0, sizeof(init));
    memset(&error, 0, sizeof(error));
    error.text_buffer_size = error_buffer_size;
    error.text = error_buffer;
 
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wformat-nonliteral"
#endif
 
    /* Establish the client connection and request upgrade */
    conn = mg_connect_client_impl(client_options, use_ssl, &init, &error);
 
    /* Connection object will be null if something goes wrong */
    if (conn == NULL) {
        /* error_buffer should be already filled ... */
        if (!error_buffer[0]) {
            /* ... if not add an error message */
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        error_buffer,
                        error_buffer_size,
                        "Unexpected error");
        }
        return NULL;
    }
 
    if (origin != NULL) {
        if (extensions != NULL) {
            i = mg_printf(conn,
                          "GET %s HTTP/1.1\r\n"
                          "Host: %s\r\n"
                          "Upgrade: websocket\r\n"
                          "Connection: Upgrade\r\n"
                          "Sec-WebSocket-Key: %s\r\n"
                          "Sec-WebSocket-Version: 13\r\n"
                          "Sec-WebSocket-Extensions: %s\r\n"
                          "Origin: %s\r\n"
                          "\r\n",
                          path,
                          host,
                          magic,
                          extensions,
                          origin);
        } else {
            i = mg_printf(conn,
                          "GET %s HTTP/1.1\r\n"
                          "Host: %s\r\n"
                          "Upgrade: websocket\r\n"
                          "Connection: Upgrade\r\n"
                          "Sec-WebSocket-Key: %s\r\n"
                          "Sec-WebSocket-Version: 13\r\n"
                          "Origin: %s\r\n"
                          "\r\n",
                          path,
                          host,
                          magic,
                          origin);
        }
    } else {
 
        if (extensions != NULL) {
            i = mg_printf(conn,
                          "GET %s HTTP/1.1\r\n"
                          "Host: %s\r\n"
                          "Upgrade: websocket\r\n"
                          "Connection: Upgrade\r\n"
                          "Sec-WebSocket-Key: %s\r\n"
                          "Sec-WebSocket-Version: 13\r\n"
                          "Sec-WebSocket-Extensions: %s\r\n"
                          "\r\n",
                          path,
                          host,
                          magic,
                          extensions);
        } else {
            i = mg_printf(conn,
                          "GET %s HTTP/1.1\r\n"
                          "Host: %s\r\n"
                          "Upgrade: websocket\r\n"
                          "Connection: Upgrade\r\n"
                          "Sec-WebSocket-Key: %s\r\n"
                          "Sec-WebSocket-Version: 13\r\n"
                          "\r\n",
                          path,
                          host,
                          magic);
        }
    }
    if (i <= 0) {
        mg_snprintf(conn,
                    NULL, /* No truncation check for ebuf */
                    error_buffer,
                    error_buffer_size,
                    "%s",
                    "Error sending request");
        mg_close_connection(conn);
        return NULL;
    }
 
    conn->data_len = 0;
    if (!get_response(conn, error_buffer, error_buffer_size, &i)) {
        mg_close_connection(conn);
        return NULL;
    }
    conn->request_info.local_uri_raw = conn->request_info.request_uri;
    conn->request_info.local_uri = conn->request_info.local_uri_raw;
 
#if defined(__clang__)
#pragma clang diagnostic pop
#endif
 
    if (conn->response_info.status_code != 101) {
        /* We sent an "upgrade" request. For a correct websocket
         * protocol handshake, we expect a "101 Continue" response.
         * Otherwise it is a protocol violation. Maybe the HTTP
         * Server does not know websockets. */
        if (!*error_buffer) {
            /* set an error, if not yet set */
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        error_buffer,
                        error_buffer_size,
                        "Unexpected server reply");
        }
 
        DEBUG_TRACE("Websocket client connect error: %s\r\n", error_buffer);
        mg_close_connection(conn);
        return NULL;
    }
 
    thread_data = (struct websocket_client_thread_data *)mg_calloc_ctx(
        1, sizeof(struct websocket_client_thread_data), conn->phys_ctx);
    if (!thread_data) {
        DEBUG_TRACE("%s\r\n", "Out of memory");
        mg_close_connection(conn);
        return NULL;
    }
 
    thread_data->conn = conn;
    thread_data->data_handler = data_func;
    thread_data->close_handler = close_func;
    thread_data->callback_data = user_data;
 
    conn->phys_ctx->worker_threadids =
        (pthread_t *)mg_calloc_ctx(1, sizeof(pthread_t), conn->phys_ctx);
    if (!conn->phys_ctx->worker_threadids) {
        DEBUG_TRACE("%s\r\n", "Out of memory");
        mg_free(thread_data);
        mg_close_connection(conn);
        return NULL;
    }
 
    /* Now upgrade to ws/wss client context */
    conn->phys_ctx->user_data = user_data;
    conn->phys_ctx->context_type = CONTEXT_WS_CLIENT;
    conn->phys_ctx->cfg_worker_threads = 1; /* one worker thread */
 
    /* Start a thread to read the websocket client connection
     * This thread will automatically stop when mg_disconnect is
     * called on the client connection */
    if (mg_start_thread_with_id(websocket_client_thread,
                                thread_data,
                                conn->phys_ctx->worker_threadids)
        != 0) {
        conn->phys_ctx->cfg_worker_threads = 0;
        mg_free(thread_data);
        mg_close_connection(conn);
        conn = NULL;
        DEBUG_TRACE("%s",
                    "Websocket client connect thread could not be started\r\n");
    }
 
#else
    /* Appease "unused parameter" warnings */
    (void)client_options;
    (void)use_ssl;
    (void)error_buffer;
    (void)error_buffer_size;
    (void)path;
    (void)origin;
    (void)extensions;
    (void)user_data;
    (void)data_func;
    (void)close_func;
#endif
 
    return conn;
}
 
 
CIVETWEB_API struct mg_connection *
mg_connect_websocket_client(const char *host,
                            int port,
                            int use_ssl,
                            char *error_buffer,
                            size_t error_buffer_size,
                            const char *path,
                            const char *origin,
                            mg_websocket_data_handler data_func,
                            mg_websocket_close_handler close_func,
                            void *user_data)
{
    struct mg_client_options client_options;
    memset(&client_options, 0, sizeof(client_options));
    client_options.host = host;
    client_options.port = port;
 
    return mg_connect_websocket_client_impl(&client_options,
                                            use_ssl,
                                            error_buffer,
                                            error_buffer_size,
                                            path,
                                            origin,
                                            NULL,
                                            data_func,
                                            close_func,
                                            user_data);
}
 
 
CIVETWEB_API struct mg_connection *
mg_connect_websocket_client_secure(
    const struct mg_client_options *client_options,
    char *error_buffer,
    size_t error_buffer_size,
    const char *path,
    const char *origin,
    mg_websocket_data_handler data_func,
    mg_websocket_close_handler close_func,
    void *user_data)
{
    if (!client_options) {
        return NULL;
    }
    return mg_connect_websocket_client_impl(client_options,
                                            1,
                                            error_buffer,
                                            error_buffer_size,
                                            path,
                                            origin,
                                            NULL,
                                            data_func,
                                            close_func,
                                            user_data);
}
 
 
CIVETWEB_API struct mg_connection *
mg_connect_websocket_client_extensions(const char *host,
                                       int port,
                                       int use_ssl,
                                       char *error_buffer,
                                       size_t error_buffer_size,
                                       const char *path,
                                       const char *origin,
                                       const char *extensions,
                                       mg_websocket_data_handler data_func,
                                       mg_websocket_close_handler close_func,
                                       void *user_data)
{
    struct mg_client_options client_options;
    memset(&client_options, 0, sizeof(client_options));
    client_options.host = host;
    client_options.port = port;
 
    return mg_connect_websocket_client_impl(&client_options,
                                            use_ssl,
                                            error_buffer,
                                            error_buffer_size,
                                            path,
                                            origin,
                                            extensions,
                                            data_func,
                                            close_func,
                                            user_data);
}
 
 
CIVETWEB_API struct mg_connection *
mg_connect_websocket_client_secure_extensions(
    const struct mg_client_options *client_options,
    char *error_buffer,
    size_t error_buffer_size,
    const char *path,
    const char *origin,
    const char *extensions,
    mg_websocket_data_handler data_func,
    mg_websocket_close_handler close_func,
    void *user_data)
{
    if (!client_options) {
        return NULL;
    }
    return mg_connect_websocket_client_impl(client_options,
                                            1,
                                            error_buffer,
                                            error_buffer_size,
                                            path,
                                            origin,
                                            extensions,
                                            data_func,
                                            close_func,
                                            user_data);
}
 
 
/* Prepare connection data structure */
static void
init_connection(struct mg_connection *conn)
{
    /* Is keep alive allowed by the server */
    int keep_alive_enabled =
        !mg_strcasecmp(conn->dom_ctx->config[ENABLE_KEEP_ALIVE], "yes");
 
    if (!keep_alive_enabled) {
        conn->must_close = 1;
    }
 
    /* Important: on new connection, reset the receiving buffer. Credit
     * goes to crule42. */
    conn->data_len = 0;
    conn->handled_requests = 0;
    conn->connection_type = CONNECTION_TYPE_INVALID;
    conn->request_info.acceptedWebSocketSubprotocol = NULL;
    mg_set_user_connection_data(conn, NULL);
 
#if defined(USE_SERVER_STATS)
    conn->conn_state = 2; /* init */
#endif
 
    /* call the init_connection callback if assigned */
    if (conn->phys_ctx->callbacks.init_connection != NULL) {
        if (conn->phys_ctx->context_type == CONTEXT_SERVER) {
            void *conn_data = NULL;
            conn->phys_ctx->callbacks.init_connection(conn, &conn_data);
            mg_set_user_connection_data(conn, conn_data);
        }
    }
}
 
 
/* Process a connection - may handle multiple requests
 * using the same connection.
 * Must be called with a valid connection (conn  and
 * conn->phys_ctx must be valid).
 */
static void
process_new_connection(struct mg_connection *conn)
{
    struct mg_request_info *ri = &conn->request_info;
    int keep_alive, discard_len;
    char ebuf[100];
    const char *hostend;
    int reqerr, uri_type;
 
#if defined(USE_SERVER_STATS)
    ptrdiff_t mcon = mg_atomic_inc(&(conn->phys_ctx->active_connections));
    mg_atomic_add(&(conn->phys_ctx->total_connections), 1);
    mg_atomic_max(&(conn->phys_ctx->max_active_connections), mcon);
#endif
 
    DEBUG_TRACE("Start processing connection from %s",
                conn->request_info.remote_addr);
 
    /* Loop over multiple requests sent using the same connection
     * (while "keep alive"). */
    do {
        DEBUG_TRACE("calling get_request (%i times for this connection)",
                    conn->handled_requests + 1);
 
#if defined(USE_SERVER_STATS)
        conn->conn_state = 3; /* ready */
#endif
 
        if (!get_request(conn, ebuf, sizeof(ebuf), &reqerr)) {
            /* The request sent by the client could not be understood by
             * the server, or it was incomplete or a timeout. Send an
             * error message and close the connection. */
            if (reqerr > 0) {
                DEBUG_ASSERT(ebuf[0] != '\0');
                mg_send_http_error(conn, reqerr, "%s", ebuf);
            }
 
        } else if (strcmp(ri->http_version, "1.0")
                   && strcmp(ri->http_version, "1.1")) {
            /* HTTP/2 is not allowed here */
            mg_snprintf(conn,
                        NULL, /* No truncation check for ebuf */
                        ebuf,
                        sizeof(ebuf),
                        "Bad HTTP version: [%s]",
                        ri->http_version);
            mg_send_http_error(conn, 505, "%s", ebuf);
        }
 
        if (ebuf[0] == '\0') {
            uri_type = get_uri_type(conn->request_info.request_uri);
            switch (uri_type) {
            case 1:
                /* Asterisk */
                conn->request_info.local_uri_raw = 0;
                /* TODO: Deal with '*'. */
                break;
            case 2:
                /* relative uri */
                conn->request_info.local_uri_raw =
                    conn->request_info.request_uri;
                break;
            case 3:
            case 4:
                /* absolute uri (with/without port) */
                hostend = get_rel_url_at_current_server(
                    conn->request_info.request_uri, conn);
                if (hostend) {
                    conn->request_info.local_uri_raw = hostend;
                } else {
                    conn->request_info.local_uri_raw = NULL;
                }
                break;
            default:
                mg_snprintf(conn,
                            NULL, /* No truncation check for ebuf */
                            ebuf,
                            sizeof(ebuf),
                            "Invalid URI");
                mg_send_http_error(conn, 400, "%s", ebuf);
                conn->request_info.local_uri_raw = NULL;
                break;
            }
            conn->request_info.local_uri =
                (char *)conn->request_info.local_uri_raw;
        }
 
        if (ebuf[0] != '\0') {
            conn->protocol_type = -1;
 
        } else {
            /* HTTP/1 allows protocol upgrade */
            conn->protocol_type = should_switch_to_protocol(conn);
 
            if (conn->protocol_type == PROTOCOL_TYPE_HTTP2) {
                /* This will occur, if a HTTP/1.1 request should be upgraded
                 * to HTTP/2 - but not if HTTP/2 is negotiated using ALPN.
                 * Since most (all?) major browsers only support HTTP/2 using
                 * ALPN, this is hard to test and very low priority.
                 * Deactivate it (at least for now).
                 */
                conn->protocol_type = PROTOCOL_TYPE_HTTP1;
            }
        }
 
        DEBUG_TRACE("http: %s, error: %s",
                    (ri->http_version ? ri->http_version : "none"),
                    (ebuf[0] ? ebuf : "none"));
 
        if (ebuf[0] == '\0') {
            if (conn->request_info.local_uri) {
 
                /* handle request to local server */
                handle_request_stat_log(conn);
 
            } else {
                /* TODO: handle non-local request (PROXY) */
                conn->must_close = 1;
            }
        } else {
            conn->must_close = 1;
        }
 
        /* Response complete. Free header buffer */
        free_buffered_response_header_list(conn);
 
        if (ri->remote_user != NULL) {
            mg_free((void *)ri->remote_user);
            /* Important! When having connections with and without auth
             * would cause double free and then crash */
            ri->remote_user = NULL;
        }
 
        /* NOTE(lsm): order is important here. should_keep_alive() call
         * is using parsed request, which will be invalid after
         * memmove's below.
         * Therefore, memorize should_keep_alive() result now for later
         * use in loop exit condition. */
        /* Enable it only if this request is completely discardable. */
        keep_alive = STOP_FLAG_IS_ZERO(&conn->phys_ctx->stop_flag)
                     && should_keep_alive(conn) && (conn->content_len >= 0)
                     && (conn->request_len > 0)
                     && ((conn->is_chunked == 4)
                         || (!conn->is_chunked
                             && ((conn->consumed_content == conn->content_len)
                                 || ((conn->request_len + conn->content_len)
                                     <= conn->data_len))))
                     && (conn->protocol_type == PROTOCOL_TYPE_HTTP1);
 
        if (keep_alive) {
            /* Discard all buffered data for this request */
            discard_len =
                ((conn->request_len + conn->content_len) < conn->data_len)
                    ? (int)(conn->request_len + conn->content_len)
                    : conn->data_len;
            conn->data_len -= discard_len;
 
            if (conn->data_len > 0) {
                DEBUG_TRACE("discard_len = %d", discard_len);
                memmove(conn->buf,
                        conn->buf + discard_len,
                        (size_t)conn->data_len);
            }
        }
 
        DEBUG_ASSERT(conn->data_len >= 0);
        DEBUG_ASSERT(conn->data_len <= conn->buf_size);
 
        if ((conn->data_len < 0) || (conn->data_len > conn->buf_size)) {
            DEBUG_TRACE("internal error: data_len = %li, buf_size = %li",
                        (long int)conn->data_len,
                        (long int)conn->buf_size);
            break;
        }
        conn->handled_requests++;
    } while (keep_alive);
 
    DEBUG_TRACE("Done processing connection from %s (%f sec)",
                conn->request_info.remote_addr,
                difftime(time(NULL), conn->conn_birth_time));
 
    close_connection(conn);
 
#if defined(USE_SERVER_STATS)
    mg_atomic_add(&(conn->phys_ctx->total_requests), conn->handled_requests);
    mg_atomic_dec(&(conn->phys_ctx->active_connections));
#endif
}
 
 
#if defined(ALTERNATIVE_QUEUE)
 
static void
produce_socket(struct mg_context *ctx, const struct socket *sp)
{
    unsigned int i;
 
    while (!ctx->stop_flag) {
        for (i = 0; i < ctx->cfg_worker_threads; i++) {
            /* find a free worker slot and signal it */
            if (ctx->client_socks[i].in_use == 2) {
                (void)pthread_mutex_lock(&ctx->thread_mutex);
                if ((ctx->client_socks[i].in_use == 2) && !ctx->stop_flag) {
                    ctx->client_socks[i] = *sp;
                    ctx->client_socks[i].in_use = 1;
                    /* socket has been moved to the consumer */
                    (void)pthread_mutex_unlock(&ctx->thread_mutex);
                    (void)event_signal(ctx->client_wait_events[i]);
                    return;
                }
                (void)pthread_mutex_unlock(&ctx->thread_mutex);
            }
        }
        /* queue is full */
        mg_sleep(1);
    }
    /* must consume */
    set_blocking_mode(sp->sock);
    closesocket(sp->sock);
}
 
 
static int
consume_socket(struct mg_context *ctx, struct socket *sp, int thread_index)
{
    DEBUG_TRACE("%s", "going idle");
    (void)pthread_mutex_lock(&ctx->thread_mutex);
    ctx->client_socks[thread_index].in_use = 2;
    (void)pthread_mutex_unlock(&ctx->thread_mutex);
 
    event_wait(ctx->client_wait_events[thread_index]);
 
    (void)pthread_mutex_lock(&ctx->thread_mutex);
    *sp = ctx->client_socks[thread_index];
    if (ctx->stop_flag) {
        (void)pthread_mutex_unlock(&ctx->thread_mutex);
        if (sp->in_use == 1) {
            /* must consume */
            set_blocking_mode(sp->sock);
            closesocket(sp->sock);
        }
        return 0;
    }
    (void)pthread_mutex_unlock(&ctx->thread_mutex);
    if (sp->in_use == 1) {
        DEBUG_TRACE("grabbed socket %d, going busy", sp->sock);
        return 1;
    }
    /* must not reach here */
    DEBUG_ASSERT(0);
    return 0;
}
 
#else /* ALTERNATIVE_QUEUE */
 
/* Worker threads take accepted socket from the queue */
static int
consume_socket(struct mg_context *ctx, struct socket *sp, int thread_index)
{
    (void)thread_index;
 
    (void)pthread_mutex_lock(&ctx->thread_mutex);
    DEBUG_TRACE("%s", "going idle");
 
    /* If the queue is empty, wait. We're idle at this point. */
    while ((ctx->sq_head == ctx->sq_tail)
           && (STOP_FLAG_IS_ZERO(&ctx->stop_flag))) {
        pthread_cond_wait(&ctx->sq_full, &ctx->thread_mutex);
    }
 
    /* If we're stopping, sq_head may be equal to sq_tail. */
    if (ctx->sq_head > ctx->sq_tail) {
        /* Copy socket from the queue and increment tail */
        *sp = ctx->squeue[ctx->sq_tail % ctx->sq_size];
        ctx->sq_tail++;
 
        DEBUG_TRACE("grabbed socket %d, going busy", sp ? sp->sock : -1);
 
        /* Wrap pointers if needed */
        while (ctx->sq_tail > ctx->sq_size) {
            ctx->sq_tail -= ctx->sq_size;
            ctx->sq_head -= ctx->sq_size;
        }
    }
 
    (void)pthread_cond_signal(&ctx->sq_empty);
    (void)pthread_mutex_unlock(&ctx->thread_mutex);
 
    return STOP_FLAG_IS_ZERO(&ctx->stop_flag);
}
 
 
/* Master thread adds accepted socket to a queue */
static void
produce_socket(struct mg_context *ctx, const struct socket *sp)
{
    int queue_filled;
 
    (void)pthread_mutex_lock(&ctx->thread_mutex);
 
    queue_filled = ctx->sq_head - ctx->sq_tail;
 
    /* If the queue is full, wait */
    while (STOP_FLAG_IS_ZERO(&ctx->stop_flag)
           && (queue_filled >= ctx->sq_size)) {
        ctx->sq_blocked = 1; /* Status information: All threads busy */
#if defined(USE_SERVER_STATS)
        if (queue_filled > ctx->sq_max_fill) {
            ctx->sq_max_fill = queue_filled;
        }
#endif
        (void)pthread_cond_wait(&ctx->sq_empty, &ctx->thread_mutex);
        ctx->sq_blocked = 0; /* Not blocked now */
        queue_filled = ctx->sq_head - ctx->sq_tail;
    }
 
    if (queue_filled < ctx->sq_size) {
        /* Copy socket to the queue and increment head */
        ctx->squeue[ctx->sq_head % ctx->sq_size] = *sp;
        ctx->sq_head++;
        DEBUG_TRACE("queued socket %d", sp ? sp->sock : -1);
    }
 
    queue_filled = ctx->sq_head - ctx->sq_tail;
#if defined(USE_SERVER_STATS)
    if (queue_filled > ctx->sq_max_fill) {
        ctx->sq_max_fill = queue_filled;
    }
#endif
 
    (void)pthread_cond_signal(&ctx->sq_full);
    (void)pthread_mutex_unlock(&ctx->thread_mutex);
}
#endif /* ALTERNATIVE_QUEUE */
 
 
static void
worker_thread_run(struct mg_connection *conn)
{
    struct mg_context *ctx = conn->phys_ctx;
    int thread_index;
    struct mg_workerTLS tls;
 
    mg_set_thread_name("worker");
 
    tls.is_master = 0;
    tls.thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
#if defined(_WIN32)
    tls.pthread_cond_helper_mutex = CreateEvent(NULL, FALSE, FALSE, NULL);
#endif
 
    /* Initialize thread local storage before calling any callback */
    pthread_setspecific(sTlsKey, &tls);
 
    /* Check if there is a user callback */
    if (ctx->callbacks.init_thread) {
        /* call init_thread for a worker thread (type 1), and store the
         * return value */
        tls.user_ptr = ctx->callbacks.init_thread(ctx, 1);
    } else {
        /* No callback: set user pointer to NULL */
        tls.user_ptr = NULL;
    }
 
    /* Connection structure has been pre-allocated */
    thread_index = (int)(conn - ctx->worker_connections);
    if ((thread_index < 0)
        || ((unsigned)thread_index >= (unsigned)ctx->cfg_worker_threads)) {
        mg_cry_ctx_internal(ctx,
                            "Internal error: Invalid worker index %i",
                            thread_index);
        return;
    }
 
    /* Request buffers are not pre-allocated. They are private to the
     * request and do not contain any state information that might be
     * of interest to anyone observing a server status.  */
    conn->buf = (char *)mg_malloc_ctx(ctx->max_request_size, conn->phys_ctx);
    if (conn->buf == NULL) {
        mg_cry_ctx_internal(
            ctx,
            "Out of memory: Cannot allocate buffer for worker %i",
            thread_index);
        return;
    }
    conn->buf_size = (int)ctx->max_request_size;
 
    conn->dom_ctx = &(ctx->dd); /* Use default domain and default host */
 
    conn->tls_user_ptr = tls.user_ptr; /* store ptr for quick access */
 
    conn->request_info.user_data = ctx->user_data;
    /* Allocate a mutex for this connection to allow communication both
     * within the request handler and from elsewhere in the application
     */
    if (0 != pthread_mutex_init(&conn->mutex, &pthread_mutex_attr)) {
        mg_free(conn->buf);
        mg_cry_ctx_internal(ctx, "%s", "Cannot create mutex");
        return;
    }
 
#if defined(USE_SERVER_STATS)
    conn->conn_state = 1; /* not consumed */
#endif
 
    /* Call consume_socket() even when ctx->stop_flag > 0, to let it
     * signal sq_empty condvar to wake up the master waiting in
     * produce_socket() */
    while (consume_socket(ctx, &conn->client, thread_index)) {
 
        /* New connections must start with new protocol negotiation */
        tls.alpn_proto = NULL;
 
#if defined(USE_SERVER_STATS)
        conn->conn_close_time = 0;
#endif
        conn->conn_birth_time = time(NULL);
 
        /* Fill in IP, port info early so even if SSL setup below fails,
         * error handler would have the corresponding info.
         * Thanks to Johannes Winkelmann for the patch.
         */
        conn->request_info.remote_port =
            ntohs(USA_IN_PORT_UNSAFE(&conn->client.rsa));
 
        conn->request_info.server_port =
            ntohs(USA_IN_PORT_UNSAFE(&conn->client.lsa));
 
        sockaddr_to_string(conn->request_info.remote_addr,
                           sizeof(conn->request_info.remote_addr),
                           &conn->client.rsa);
 
        DEBUG_TRACE("Incoming %sconnection from %s",
                    (conn->client.is_ssl ? "SSL " : ""),
                    conn->request_info.remote_addr);
 
        conn->request_info.is_ssl = conn->client.is_ssl;
 
        if (conn->client.is_ssl) {
 
#if defined(USE_MBEDTLS)
            /* HTTPS connection */
            if (mbed_ssl_accept(&(conn->ssl),
                                conn->dom_ctx->ssl_ctx,
                                (int *)&(conn->client.sock),
                                conn->phys_ctx)
                == 0) {
                /* conn->dom_ctx is set in get_request */
                /* process HTTPS connection */
                init_connection(conn);
                conn->connection_type = CONNECTION_TYPE_REQUEST;
                conn->protocol_type = PROTOCOL_TYPE_HTTP1;
                process_new_connection(conn);
            } else {
                /* make sure the connection is cleaned up on SSL failure */
                close_connection(conn);
            }
 
#elif !defined(NO_SSL)
            /* HTTPS connection */
            if (sslize(conn, SSL_accept, NULL)) {
                /* conn->dom_ctx is set in get_request */
 
                /* Get SSL client certificate information (if set) */
                struct mg_client_cert client_cert;
                if (ssl_get_client_cert_info(conn, &client_cert)) {
                    conn->request_info.client_cert = &client_cert;
                }
 
                /* process HTTPS connection */
#if defined(USE_HTTP2)
                if ((tls.alpn_proto != NULL)
                    && (!memcmp(tls.alpn_proto, "\x02h2", 3))) {
                    /* process HTTPS/2 connection */
                    init_connection(conn);
                    conn->connection_type = CONNECTION_TYPE_REQUEST;
                    conn->protocol_type = PROTOCOL_TYPE_HTTP2;
                    conn->content_len =
                        -1;               /* content length is not predefined */
                    conn->is_chunked = 0; /* HTTP2 is never chunked */
                    process_new_http2_connection(conn);
                } else
#endif
                {
                    /* process HTTPS/1.x or WEBSOCKET-SECURE connection */
                    init_connection(conn);
                    conn->connection_type = CONNECTION_TYPE_REQUEST;
                    /* Start with HTTP, WS will be an "upgrade" request later */
                    conn->protocol_type = PROTOCOL_TYPE_HTTP1;
                    process_new_connection(conn);
                }
 
                /* Free client certificate info */
                if (conn->request_info.client_cert) {
                    mg_free((void *)(conn->request_info.client_cert->subject));
                    mg_free((void *)(conn->request_info.client_cert->issuer));
                    mg_free((void *)(conn->request_info.client_cert->serial));
                    mg_free((void *)(conn->request_info.client_cert->finger));
                    /* Free certificate memory */
                    X509_free(
                        (X509 *)conn->request_info.client_cert->peer_cert);
                    conn->request_info.client_cert->peer_cert = 0;
                    conn->request_info.client_cert->subject = 0;
                    conn->request_info.client_cert->issuer = 0;
                    conn->request_info.client_cert->serial = 0;
                    conn->request_info.client_cert->finger = 0;
                    conn->request_info.client_cert = 0;
                }
            } else {
                /* make sure the connection is cleaned up on SSL failure */
                close_connection(conn);
            }
#endif
 
        } else {
            /* process HTTP connection */
            init_connection(conn);
            conn->connection_type = CONNECTION_TYPE_REQUEST;
            /* Start with HTTP, WS will be an "upgrade" request later */
            conn->protocol_type = PROTOCOL_TYPE_HTTP1;
            process_new_connection(conn);
        }
 
        DEBUG_TRACE("%s", "Connection closed");
 
#if defined(USE_SERVER_STATS)
        conn->conn_close_time = time(NULL);
#endif
    }
 
    /* Call exit thread user callback */
    if (ctx->callbacks.exit_thread) {
        ctx->callbacks.exit_thread(ctx, 1, tls.user_ptr);
    }
 
    /* delete thread local storage objects */
    pthread_setspecific(sTlsKey, NULL);
#if defined(_WIN32)
    CloseHandle(tls.pthread_cond_helper_mutex);
#endif
    pthread_mutex_destroy(&conn->mutex);
 
    /* Free the request buffer. */
    conn->buf_size = 0;
    mg_free(conn->buf);
    conn->buf = NULL;
 
    /* Free cleaned URI (if any) */
    if (conn->request_info.local_uri != conn->request_info.local_uri_raw) {
        mg_free((void *)conn->request_info.local_uri);
        conn->request_info.local_uri = NULL;
    }
 
#if defined(USE_SERVER_STATS)
    conn->conn_state = 9; /* done */
#endif
 
    DEBUG_TRACE("%s", "exiting");
}
 
 
/* Threads have different return types on Windows and Unix. */
#if defined(_WIN32)
static unsigned __stdcall worker_thread(void *thread_func_param)
{
    worker_thread_run((struct mg_connection *)thread_func_param);
    return 0;
}
#else
static void *
worker_thread(void *thread_func_param)
{
#if !defined(__ZEPHYR__)
    struct sigaction sa;
 
    /* Ignore SIGPIPE */
    memset(&sa, 0, sizeof(sa));
    sa.sa_handler = SIG_IGN;
    sigaction(SIGPIPE, &sa, NULL);
#endif
 
    worker_thread_run((struct mg_connection *)thread_func_param);
    return NULL;
}
#endif /* _WIN32 */
 
 
/* This is an internal function, thus all arguments are expected to be
 * valid - a NULL check is not required. */
static void
accept_new_connection(const struct socket *listener, struct mg_context *ctx)
{
    struct socket so;
    char src_addr[IP_ADDR_STR_LEN];
    socklen_t len = sizeof(so.rsa);
#if !defined(__ZEPHYR__)
    int on = 1;
#endif
    memset(&so, 0, sizeof(so));
 
    if ((so.sock = accept(listener->sock, &so.rsa.sa, &len))
        == INVALID_SOCKET) {
    } else if (check_acl(ctx, &so.rsa) != 1) {
        sockaddr_to_string(src_addr, sizeof(src_addr), &so.rsa);
        mg_cry_ctx_internal(ctx,
                            "%s: %s is not allowed to connect",
                            __func__,
                            src_addr);
        closesocket(so.sock);
    } else {
        /* Put so socket structure into the queue */
        DEBUG_TRACE("Accepted socket %d", (int)so.sock);
        set_close_on_exec(so.sock, NULL, ctx);
        so.is_ssl = listener->is_ssl;
        so.ssl_redir = listener->ssl_redir;
        if (getsockname(so.sock, &so.lsa.sa, &len) != 0) {
            mg_cry_ctx_internal(ctx,
                                "%s: getsockname() failed: %s",
                                __func__,
                                strerror(ERRNO));
        }
 
#if !defined(__ZEPHYR__)
        if ((so.lsa.sa.sa_family == AF_INET)
            || (so.lsa.sa.sa_family == AF_INET6)) {
            /* Set TCP keep-alive for TCP sockets (IPv4 and IPv6).
             * This is needed because if HTTP-level keep-alive
             * is enabled, and client resets the connection, server won't get
             * TCP FIN or RST and will keep the connection open forever. With
             * TCP keep-alive, next keep-alive handshake will figure out that
             * the client is down and will close the server end.
             * Thanks to Igor Klopov who suggested the patch. */
            if (setsockopt(so.sock,
                           SOL_SOCKET,
                           SO_KEEPALIVE,
                           (SOCK_OPT_TYPE)&on,
                           sizeof(on))
                != 0) {
                mg_cry_ctx_internal(
                    ctx,
                    "%s: setsockopt(SOL_SOCKET SO_KEEPALIVE) failed: %s",
                    __func__,
                    strerror(ERRNO));
            }
        }
#endif
 
        /* Disable TCP Nagle's algorithm. Normally TCP packets are coalesced
         * to effectively fill up the underlying IP packet payload and
         * reduce the overhead of sending lots of small buffers. However
         * this hurts the server's throughput (ie. operations per second)
         * when HTTP 1.1 persistent connections are used and the responses
         * are relatively small (eg. less than 1400 bytes).
         */
        if ((ctx->dd.config[CONFIG_TCP_NODELAY] != NULL)
            && (!strcmp(ctx->dd.config[CONFIG_TCP_NODELAY], "1"))) {
            if (set_tcp_nodelay(&so, 1) != 0) {
                mg_cry_ctx_internal(
                    ctx,
                    "%s: setsockopt(IPPROTO_TCP TCP_NODELAY) failed: %s",
                    __func__,
                    strerror(ERRNO));
            }
        }
 
        /* The "non blocking" property should already be
         * inherited from the parent socket. Set it for
         * non-compliant socket implementations. */
        set_non_blocking_mode(so.sock);
 
        so.in_use = 0;
        produce_socket(ctx, &so);
    }
}
 
 
static void
master_thread_run(struct mg_context *ctx)
{
    struct mg_workerTLS tls;
    struct mg_pollfd *pfd;
    unsigned int i;
    unsigned int workerthreadcount;
 
    if (!ctx) {
        return;
    }
 
    mg_set_thread_name("master");
 
    /* Increase priority of the master thread */
#if defined(_WIN32)
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_ABOVE_NORMAL);
#elif defined(USE_MASTER_THREAD_PRIORITY)
    int min_prio = sched_get_priority_min(SCHED_RR);
    int max_prio = sched_get_priority_max(SCHED_RR);
    if ((min_prio >= 0) && (max_prio >= 0)
        && ((USE_MASTER_THREAD_PRIORITY) <= max_prio)
        && ((USE_MASTER_THREAD_PRIORITY) >= min_prio)) {
        struct sched_param sched_param = {0};
        sched_param.sched_priority = (USE_MASTER_THREAD_PRIORITY);
        pthread_setschedparam(pthread_self(), SCHED_RR, &sched_param);
    }
#endif
 
    /* Initialize thread local storage */
#if defined(_WIN32)
    tls.pthread_cond_helper_mutex = CreateEvent(NULL, FALSE, FALSE, NULL);
#endif
    tls.is_master = 1;
    pthread_setspecific(sTlsKey, &tls);
 
    if (ctx->callbacks.init_thread) {
        /* Callback for the master thread (type 0) */
        tls.user_ptr = ctx->callbacks.init_thread(ctx, 0);
    } else {
        tls.user_ptr = NULL;
    }
 
    /* Lua background script "start" event */
#if defined(USE_LUA)
    if (ctx->lua_background_state) {
        lua_State *lstate = (lua_State *)ctx->lua_background_state;
        pthread_mutex_lock(&ctx->lua_bg_mutex);
 
        /* call "start()" in Lua */
        lua_getglobal(lstate, "start");
        if (lua_type(lstate, -1) == LUA_TFUNCTION) {
            int ret = lua_pcall(lstate, /* args */ 0, /* results */ 0, 0);
            if (ret != 0) {
                struct mg_connection fc;
                lua_cry(fake_connection(&fc, ctx),
                        ret,
                        lstate,
                        "lua_background_script",
                        "start");
            }
        } else {
            lua_pop(lstate, 1);
        }
 
        /* determine if there is a "log()" function in Lua background script */
        lua_getglobal(lstate, "log");
        if (lua_type(lstate, -1) == LUA_TFUNCTION) {
            ctx->lua_bg_log_available = 1;
        }
        lua_pop(lstate, 1);
 
        pthread_mutex_unlock(&ctx->lua_bg_mutex);
    }
#endif
 
    /* Server starts *now* */
    ctx->start_time = time(NULL);
 
    /* Server accept loop */
    pfd = ctx->listening_socket_fds;
    while (STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
        for (i = 0; i < ctx->num_listening_sockets; i++) {
            pfd[i].fd = ctx->listening_sockets[i].sock;
            pfd[i].events = POLLIN;
        }
 
        if (mg_poll(pfd,
                    ctx->num_listening_sockets,
                    SOCKET_TIMEOUT_QUANTUM,
                    &(ctx->stop_flag))
            > 0) {
            for (i = 0; i < ctx->num_listening_sockets; i++) {
                /* NOTE(lsm): on QNX, poll() returns POLLRDNORM after the
                 * successful poll, and POLLIN is defined as
                 * (POLLRDNORM | POLLRDBAND)
                 * Therefore, we're checking pfd[i].revents & POLLIN, not
                 * pfd[i].revents == POLLIN. */
                if (STOP_FLAG_IS_ZERO(&ctx->stop_flag)
                    && (pfd[i].revents & POLLIN)) {
                    accept_new_connection(&ctx->listening_sockets[i], ctx);
                }
            }
        }
    }
 
    /* Here stop_flag is 1 - Initiate shutdown. */
    DEBUG_TRACE("%s", "stopping workers");
 
    /* Stop signal received: somebody called mg_stop. Quit. */
    close_all_listening_sockets(ctx);
 
    /* Wakeup workers that are waiting for connections to handle. */
#if defined(ALTERNATIVE_QUEUE)
    for (i = 0; i < ctx->cfg_worker_threads; i++) {
        event_signal(ctx->client_wait_events[i]);
    }
#else
    (void)pthread_mutex_lock(&ctx->thread_mutex);
    pthread_cond_broadcast(&ctx->sq_full);
    (void)pthread_mutex_unlock(&ctx->thread_mutex);
#endif
 
    /* Join all worker threads to avoid leaking threads. */
    workerthreadcount = ctx->cfg_worker_threads;
    for (i = 0; i < workerthreadcount; i++) {
        if (ctx->worker_threadids[i] != 0) {
            mg_join_thread(ctx->worker_threadids[i]);
        }
    }
 
#if defined(USE_LUA)
    /* Free Lua state of lua background task */
    if (ctx->lua_background_state) {
        lua_State *lstate = (lua_State *)ctx->lua_background_state;
        ctx->lua_bg_log_available = 0;
 
        /* call "stop()" in Lua */
        pthread_mutex_lock(&ctx->lua_bg_mutex);
        lua_getglobal(lstate, "stop");
        if (lua_type(lstate, -1) == LUA_TFUNCTION) {
            int ret = lua_pcall(lstate, /* args */ 0, /* results */ 0, 0);
            if (ret != 0) {
                struct mg_connection fc;
                lua_cry(fake_connection(&fc, ctx),
                        ret,
                        lstate,
                        "lua_background_script",
                        "stop");
            }
        }
        DEBUG_TRACE("Close Lua background state %p", lstate);
        lua_close(lstate);
 
        ctx->lua_background_state = 0;
        pthread_mutex_unlock(&ctx->lua_bg_mutex);
    }
#endif
 
    DEBUG_TRACE("%s", "exiting");
 
    /* call exit thread callback */
    if (ctx->callbacks.exit_thread) {
        /* Callback for the master thread (type 0) */
        ctx->callbacks.exit_thread(ctx, 0, tls.user_ptr);
    }
 
#if defined(_WIN32)
    CloseHandle(tls.pthread_cond_helper_mutex);
#endif
    pthread_setspecific(sTlsKey, NULL);
 
    /* Signal mg_stop() that we're done.
     * WARNING: This must be the very last thing this
     * thread does, as ctx becomes invalid after this line. */
    STOP_FLAG_ASSIGN(&ctx->stop_flag, 2);
}
 
 
/* Threads have different return types on Windows and Unix. */
#if defined(_WIN32)
static unsigned __stdcall master_thread(void *thread_func_param)
{
    master_thread_run((struct mg_context *)thread_func_param);
    return 0;
}
#else
static void *
master_thread(void *thread_func_param)
{
#if !defined(__ZEPHYR__)
    struct sigaction sa;
 
    /* Ignore SIGPIPE */
    memset(&sa, 0, sizeof(sa));
    sa.sa_handler = SIG_IGN;
    sigaction(SIGPIPE, &sa, NULL);
#endif
 
    master_thread_run((struct mg_context *)thread_func_param);
    return NULL;
}
#endif /* _WIN32 */
 
 
static void
free_context(struct mg_context *ctx)
{
    int i;
    struct mg_handler_info *tmp_rh;
 
    if (ctx == NULL) {
        return;
    }
 
    /* Call user callback */
    if (ctx->callbacks.exit_context) {
        ctx->callbacks.exit_context(ctx);
    }
 
    /* All threads exited, no sync is needed. Destroy thread mutex and
     * condvars
     */
    (void)pthread_mutex_destroy(&ctx->thread_mutex);
 
#if defined(ALTERNATIVE_QUEUE)
    mg_free(ctx->client_socks);
    if (ctx->client_wait_events != NULL) {
        for (i = 0; (unsigned)i < ctx->cfg_worker_threads; i++) {
            event_destroy(ctx->client_wait_events[i]);
        }
        mg_free(ctx->client_wait_events);
    }
#else
    (void)pthread_cond_destroy(&ctx->sq_empty);
    (void)pthread_cond_destroy(&ctx->sq_full);
    mg_free(ctx->squeue);
#endif
 
    /* Destroy other context global data structures mutex */
    (void)pthread_mutex_destroy(&ctx->nonce_mutex);
 
#if defined(USE_LUA)
    (void)pthread_mutex_destroy(&ctx->lua_bg_mutex);
#endif
 
    /* Deallocate config parameters */
    for (i = 0; i < NUM_OPTIONS; i++) {
        if (ctx->dd.config[i] != NULL) {
#if defined(_MSC_VER)
#pragma warning(suppress : 6001)
#endif
            mg_free(ctx->dd.config[i]);
        }
    }
 
    /* Deallocate request handlers */
    while (ctx->dd.handlers) {
        tmp_rh = ctx->dd.handlers;
        ctx->dd.handlers = tmp_rh->next;
        mg_free(tmp_rh->uri);
        mg_free(tmp_rh);
    }
 
#if defined(USE_MBEDTLS)
    if (ctx->dd.ssl_ctx != NULL) {
        mbed_sslctx_uninit(ctx->dd.ssl_ctx);
        mg_free(ctx->dd.ssl_ctx);
        ctx->dd.ssl_ctx = NULL;
    }
 
#elif !defined(NO_SSL)
    /* Deallocate SSL context */
    if (ctx->dd.ssl_ctx != NULL) {
        void *ssl_ctx = (void *)ctx->dd.ssl_ctx;
        int callback_ret =
            (ctx->callbacks.external_ssl_ctx == NULL)
                ? 0
                : (ctx->callbacks.external_ssl_ctx(&ssl_ctx, ctx->user_data));
 
        if (callback_ret == 0) {
            SSL_CTX_free(ctx->dd.ssl_ctx);
        }
        /* else: ignore error and omit SSL_CTX_free in case
         * callback_ret is 1 */
    }
#endif /* !NO_SSL */
 
    /* Deallocate worker thread ID array */
    mg_free(ctx->worker_threadids);
 
    /* Deallocate worker thread ID array */
    mg_free(ctx->worker_connections);
 
    /* deallocate system name string */
    mg_free(ctx->systemName);
 
    /* Deallocate context itself */
    mg_free(ctx);
}
 
 
CIVETWEB_API void
mg_stop(struct mg_context *ctx)
{
    pthread_t mt;
    if (!ctx) {
        return;
    }
 
    /* We don't use a lock here. Calling mg_stop with the same ctx from
     * two threads is not allowed. */
    mt = ctx->masterthreadid;
    if (mt == 0) {
        return;
    }
 
    ctx->masterthreadid = 0;
 
    /* Set stop flag, so all threads know they have to exit. */
    STOP_FLAG_ASSIGN(&ctx->stop_flag, 1);
 
    /* Join timer thread */
#if defined(USE_TIMERS)
    timers_exit(ctx);
#endif
 
    /* Wait until everything has stopped. */
    while (!STOP_FLAG_IS_TWO(&ctx->stop_flag)) {
        (void)mg_sleep(10);
    }
 
    /* Wait to stop master thread */
    mg_join_thread(mt);
 
    /* Close remaining Lua states */
#if defined(USE_LUA)
    lua_ctx_exit(ctx);
#endif
 
    /* Free memory */
    free_context(ctx);
}
 
 
static void
get_system_name(char **sysName)
{
#if defined(_WIN32)
    char name[128];
    DWORD dwVersion = 0;
    DWORD dwMajorVersion = 0;
    DWORD dwMinorVersion = 0;
    DWORD dwBuild = 0;
    BOOL wowRet, isWoW = FALSE;
 
#if defined(_MSC_VER)
#pragma warning(push)
    /* GetVersion was declared deprecated */
#pragma warning(disable : 4996)
#endif
    dwVersion = GetVersion();
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
 
    dwMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
    dwMinorVersion = (DWORD)(HIBYTE(LOWORD(dwVersion)));
    dwBuild = ((dwVersion < 0x80000000) ? (DWORD)(HIWORD(dwVersion)) : 0);
    (void)dwBuild;
 
    wowRet = IsWow64Process(GetCurrentProcess(), &isWoW);
 
    sprintf(name,
            "Windows %u.%u%s",
            (unsigned)dwMajorVersion,
            (unsigned)dwMinorVersion,
            (wowRet ? (isWoW ? " (WoW64)" : "") : " (?)"));
 
    *sysName = mg_strdup(name);
 
#elif defined(__ZEPHYR__)
    *sysName = mg_strdup("Zephyr OS");
#else
    struct utsname name;
    memset(&name, 0, sizeof(name));
    uname(&name);
    *sysName = mg_strdup(name.sysname);
#endif
}
 
 
static void
legacy_init(const char **options)
{
    const char *ports_option = config_options[LISTENING_PORTS].default_value;
 
    if (options) {
        const char **run_options = options;
        const char *optname = config_options[LISTENING_PORTS].name;
 
        /* Try to find the "listening_ports" option */
        while (*run_options) {
            if (!strcmp(*run_options, optname)) {
                ports_option = run_options[1];
            }
            run_options += 2;
        }
    }
 
    if (is_ssl_port_used(ports_option)) {
        /* Initialize with SSL support */
        mg_init_library(MG_FEATURES_TLS);
    } else {
        /* Initialize without SSL support */
        mg_init_library(MG_FEATURES_DEFAULT);
    }
}
 
 
CIVETWEB_API struct mg_context *
mg_start2(struct mg_init_data *init, struct mg_error_data *error)
{
    struct mg_context *ctx;
    const char *name, *value, *default_value;
    int idx, ok, workerthreadcount;
    unsigned int i;
    int itmp;
    void (*exit_callback)(const struct mg_context *ctx) = 0;
    const char **options =
        ((init != NULL) ? (init->configuration_options) : (NULL));
 
    struct mg_workerTLS tls;
 
    if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_OK;
        error->code_sub = 0;
        if (error->text_buffer_size > 0) {
            *error->text = 0;
        }
    }
 
    if (mg_init_library_called == 0) {
        /* Legacy INIT, if mg_start is called without mg_init_library.
         * Note: This will cause a memory leak when unloading the library.
         */
        legacy_init(options);
    }
    if (mg_init_library_called == 0) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_LIBRARY_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "Library uninitialized");
        }
        return NULL;
    }
 
    /* Allocate context and initialize reasonable general case defaults. */
    ctx = (struct mg_context *)mg_calloc(1, sizeof(*ctx));
    if (ctx == NULL) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub = (unsigned)sizeof(*ctx);
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "Out of memory");
        }
        return NULL;
    }
 
    /* Random number generator will initialize at the first call */
    ctx->dd.auth_nonce_mask =
        (uint64_t)get_random() ^ (uint64_t)(ptrdiff_t)(options);
 
    /* Save started thread index to reuse in other external API calls
     * For the sake of thread synchronization all non-civetweb threads
     * can be considered as single external thread */
    ctx->starter_thread_idx = (unsigned)mg_atomic_inc(&thread_idx_max);
    tls.is_master = -1; /* Thread calling mg_start */
    tls.thread_idx = ctx->starter_thread_idx;
#if defined(_WIN32)
    tls.pthread_cond_helper_mutex = NULL;
#endif
    pthread_setspecific(sTlsKey, &tls);
 
    ok = (0 == pthread_mutex_init(&ctx->thread_mutex, &pthread_mutex_attr));
#if !defined(ALTERNATIVE_QUEUE)
    ok &= (0 == pthread_cond_init(&ctx->sq_empty, NULL));
    ok &= (0 == pthread_cond_init(&ctx->sq_full, NULL));
    ctx->sq_blocked = 0;
#endif
    ok &= (0 == pthread_mutex_init(&ctx->nonce_mutex, &pthread_mutex_attr));
#if defined(USE_LUA)
    ok &= (0 == pthread_mutex_init(&ctx->lua_bg_mutex, &pthread_mutex_attr));
#endif
    if (!ok) {
        unsigned error_id = (unsigned)ERRNO;
        const char *err_msg =
            "Cannot initialize thread synchronization objects";
        /* Fatal error - abort start. However, this situation should never
         * occur in practice. */
 
        mg_cry_ctx_internal(ctx, "%s", err_msg);
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OS_ERROR;
            error->code_sub = error_id;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        mg_free(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
    if ((init != NULL) && (init->callbacks != NULL)) {
        /* Set all callbacks except exit_context. */
        ctx->callbacks = *init->callbacks;
        exit_callback = init->callbacks->exit_context;
        /* The exit callback is activated once the context is successfully
         * created. It should not be called, if an incomplete context object
         * is deleted during a failed initialization. */
        ctx->callbacks.exit_context = 0;
    }
    ctx->user_data = ((init != NULL) ? (init->user_data) : (NULL));
    ctx->dd.handlers = NULL;
    ctx->dd.next = NULL;
 
#if defined(USE_LUA)
    lua_ctx_init(ctx);
#endif
 
    /* Store options */
    while (options && (name = *options++) != NULL) {
        idx = get_option_index(name);
        if (idx == -1) {
            mg_cry_ctx_internal(ctx, "Invalid option: %s", name);
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
                error->code_sub = (unsigned)-1;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            "Invalid configuration option: %s",
                            name);
            }
 
            free_context(ctx);
            pthread_setspecific(sTlsKey, NULL);
            return NULL;
 
        } else if ((value = *options++) == NULL) {
            mg_cry_ctx_internal(ctx, "%s: option value cannot be NULL", name);
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
                error->code_sub = (unsigned)idx;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            "Invalid configuration option value: %s",
                            name);
            }
 
            free_context(ctx);
            pthread_setspecific(sTlsKey, NULL);
            return NULL;
        }
        if (ctx->dd.config[idx] != NULL) {
            /* A duplicate configuration option is not an error - the last
             * option value will be used. */
            mg_cry_ctx_internal(ctx, "warning: %s: duplicate option", name);
            mg_free(ctx->dd.config[idx]);
        }
        ctx->dd.config[idx] = mg_strdup_ctx(value, ctx);
        DEBUG_TRACE("[%s] -> [%s]", name, value);
    }
 
    /* Set default value if needed */
    for (i = 0; config_options[i].name != NULL; i++) {
        default_value = config_options[i].default_value;
        if ((ctx->dd.config[i] == NULL) && (default_value != NULL)) {
            ctx->dd.config[i] = mg_strdup_ctx(default_value, ctx);
        }
    }
 
    /* Request size option */
    itmp = atoi(ctx->dd.config[MAX_REQUEST_SIZE]);
    if (itmp < 1024) {
        mg_cry_ctx_internal(ctx,
                            "%s too small",
                            config_options[MAX_REQUEST_SIZE].name);
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
            error->code_sub = (unsigned)MAX_REQUEST_SIZE;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Invalid configuration option value: %s",
                        config_options[MAX_REQUEST_SIZE].name);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
    ctx->max_request_size = (unsigned)itmp;
 
    /* Queue length */
#if !defined(ALTERNATIVE_QUEUE)
    itmp = atoi(ctx->dd.config[CONNECTION_QUEUE_SIZE]);
    if (itmp < 1) {
        mg_cry_ctx_internal(ctx,
                            "%s too small",
                            config_options[CONNECTION_QUEUE_SIZE].name);
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
            error->code_sub = CONNECTION_QUEUE_SIZE;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Invalid configuration option value: %s",
                        config_options[CONNECTION_QUEUE_SIZE].name);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
    ctx->squeue =
        (struct socket *)mg_calloc((unsigned int)itmp, sizeof(struct socket));
    if (ctx->squeue == NULL) {
        mg_cry_ctx_internal(ctx,
                            "Out of memory: Cannot allocate %s",
                            config_options[CONNECTION_QUEUE_SIZE].name);
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub = (unsigned)itmp * (unsigned)sizeof(struct socket);
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Out of memory: Cannot allocate %s",
                        config_options[CONNECTION_QUEUE_SIZE].name);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
    ctx->sq_size = itmp;
#endif
 
    /* Worker thread count option */
    workerthreadcount = atoi(ctx->dd.config[NUM_THREADS]);
 
    if ((workerthreadcount > MAX_WORKER_THREADS) || (workerthreadcount <= 0)) {
        if (workerthreadcount <= 0) {
            mg_cry_ctx_internal(ctx, "%s", "Invalid number of worker threads");
        } else {
            mg_cry_ctx_internal(ctx, "%s", "Too many worker threads");
        }
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
            error->code_sub = NUM_THREADS;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Invalid configuration option value: %s",
                        config_options[NUM_THREADS].name);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
    /* Document root */
#if defined(NO_FILES)
    if (ctx->dd.config[DOCUMENT_ROOT] != NULL) {
        mg_cry_ctx_internal(ctx, "%s", "Document root must not be set");
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
            error->code_sub = (unsigned)DOCUMENT_ROOT;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Invalid configuration option value: %s",
                        config_options[DOCUMENT_ROOT].name);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
#endif
 
    get_system_name(&ctx->systemName);
 
#if defined(USE_LUA)
    /* If a Lua background script has been configured, start it. */
    ctx->lua_bg_log_available = 0;
    if (ctx->dd.config[LUA_BACKGROUND_SCRIPT] != NULL) {
        char ebuf[256];
        struct vec opt_vec;
        struct vec eq_vec;
        const char *sparams;
 
        memset(ebuf, 0, sizeof(ebuf));
        pthread_mutex_lock(&ctx->lua_bg_mutex);
 
        /* Create a Lua state, load all standard libraries and the mg table */
        lua_State *state = mg_lua_context_script_prepare(
            ctx->dd.config[LUA_BACKGROUND_SCRIPT], ctx, ebuf, sizeof(ebuf));
        if (!state) {
            mg_cry_ctx_internal(ctx,
                                "lua_background_script load error: %s",
                                ebuf);
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_SCRIPT_ERROR;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            "Error in script %s: %s",
                            config_options[LUA_BACKGROUND_SCRIPT].name,
                            ebuf);
            }
 
            pthread_mutex_unlock(&ctx->lua_bg_mutex);
 
            free_context(ctx);
            pthread_setspecific(sTlsKey, NULL);
            return NULL;
        }
 
        /* Add a table with parameters into mg.params */
        sparams = ctx->dd.config[LUA_BACKGROUND_SCRIPT_PARAMS];
        if (sparams && sparams[0]) {
            lua_getglobal(state, "mg");
            lua_pushstring(state, "params");
            lua_newtable(state);
 
            while ((sparams = next_option(sparams, &opt_vec, &eq_vec))
                   != NULL) {
                reg_llstring(
                    state, opt_vec.ptr, opt_vec.len, eq_vec.ptr, eq_vec.len);
                if (mg_strncasecmp(sparams, opt_vec.ptr, opt_vec.len) == 0)
                    break;
            }
            lua_rawset(state, -3);
            lua_pop(state, 1);
        }
 
        /* Call script */
        state = mg_lua_context_script_run(state,
                                          ctx->dd.config[LUA_BACKGROUND_SCRIPT],
                                          ctx,
                                          ebuf,
                                          sizeof(ebuf));
        if (!state) {
            mg_cry_ctx_internal(ctx,
                                "lua_background_script start error: %s",
                                ebuf);
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_SCRIPT_ERROR;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            "Error in script %s: %s",
                            config_options[DOCUMENT_ROOT].name,
                            ebuf);
            }
            pthread_mutex_unlock(&ctx->lua_bg_mutex);
 
            free_context(ctx);
            pthread_setspecific(sTlsKey, NULL);
            return NULL;
        }
 
        /* state remains valid */
        ctx->lua_background_state = (void *)state;
        pthread_mutex_unlock(&ctx->lua_bg_mutex);
 
    } else {
        ctx->lua_background_state = 0;
    }
#endif
 
    /* Step by step initialization of ctx - depending on build options */
#if !defined(NO_FILESYSTEMS)
    if (!set_gpass_option(ctx, NULL)) {
        const char *err_msg = "Invalid global password file";
        /* Fatal error - abort start. */
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_PASS_FILE;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
#endif
 
#if defined(USE_MBEDTLS)
    if (!mg_sslctx_init(ctx, NULL)) {
        const char *err_msg = "Error initializing SSL context";
        /* Fatal error - abort start. */
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
#elif !defined(NO_SSL)
    if (!init_ssl_ctx(ctx, NULL)) {
        const char *err_msg = "Error initializing SSL context";
        /* Fatal error - abort start. */
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
#endif
 
    if (!set_ports_option(ctx)) {
        const char *err_msg = "Failed to setup server ports";
        /* Fatal error - abort start. */
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_PORTS_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
#if !defined(_WIN32) && !defined(__ZEPHYR__)
    if (!set_uid_option(ctx)) {
        const char *err_msg = "Failed to run as configured user";
        /* Fatal error - abort start. */
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_USER_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
#endif
 
    if (!set_acl_option(ctx)) {
        const char *err_msg = "Failed to setup access control list";
        /* Fatal error - abort start. */
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_ACL_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
    ctx->cfg_worker_threads = ((unsigned int)(workerthreadcount));
    ctx->worker_threadids = (pthread_t *)mg_calloc_ctx(ctx->cfg_worker_threads,
                                                       sizeof(pthread_t),
                                                       ctx);
 
    if (ctx->worker_threadids == NULL) {
        const char *err_msg = "Not enough memory for worker thread ID array";
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub =
                (unsigned)ctx->cfg_worker_threads * (unsigned)sizeof(pthread_t);
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
    ctx->worker_connections =
        (struct mg_connection *)mg_calloc_ctx(ctx->cfg_worker_threads,
                                              sizeof(struct mg_connection),
                                              ctx);
    if (ctx->worker_connections == NULL) {
        const char *err_msg =
            "Not enough memory for worker thread connection array";
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub = (unsigned)ctx->cfg_worker_threads
                              * (unsigned)sizeof(struct mg_connection);
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
#if defined(ALTERNATIVE_QUEUE)
    ctx->client_wait_events =
        (void **)mg_calloc_ctx(ctx->cfg_worker_threads,
                               sizeof(ctx->client_wait_events[0]),
                               ctx);
    if (ctx->client_wait_events == NULL) {
        const char *err_msg = "Not enough memory for worker event array";
        mg_cry_ctx_internal(ctx, "%s", err_msg);
        mg_free(ctx->worker_threadids);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub = (unsigned)ctx->cfg_worker_threads
                              * (unsigned)sizeof(ctx->client_wait_events[0]);
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
    ctx->client_socks =
        (struct socket *)mg_calloc_ctx(ctx->cfg_worker_threads,
                                       sizeof(ctx->client_socks[0]),
                                       ctx);
    if (ctx->client_socks == NULL) {
        const char *err_msg = "Not enough memory for worker socket array";
        mg_cry_ctx_internal(ctx, "%s", err_msg);
        mg_free(ctx->client_wait_events);
        mg_free(ctx->worker_threadids);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub = (unsigned)ctx->cfg_worker_threads
                              * (unsigned)sizeof(ctx->client_socks[0]);
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
 
    for (i = 0; (unsigned)i < ctx->cfg_worker_threads; i++) {
        ctx->client_wait_events[i] = event_create();
        if (ctx->client_wait_events[i] == 0) {
            const char *err_msg = "Error creating worker event %i";
            mg_cry_ctx_internal(ctx, err_msg, i);
            while (i > 0) {
                i--;
                event_destroy(ctx->client_wait_events[i]);
            }
            mg_free(ctx->client_socks);
            mg_free(ctx->client_wait_events);
            mg_free(ctx->worker_threadids);
 
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_OS_ERROR;
                error->code_sub = (unsigned)ERRNO;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            err_msg,
                            i);
            }
 
            free_context(ctx);
            pthread_setspecific(sTlsKey, NULL);
            return NULL;
        }
    }
#endif
 
#if defined(USE_TIMERS)
    if (timers_init(ctx) != 0) {
        const char *err_msg = "Error creating timers";
        mg_cry_ctx_internal(ctx, "%s", err_msg);
 
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OS_ERROR;
            error->code_sub = (unsigned)ERRNO;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        err_msg);
        }
 
        free_context(ctx);
        pthread_setspecific(sTlsKey, NULL);
        return NULL;
    }
#endif
 
    /* Context has been created - init user libraries */
    if (ctx->callbacks.init_context) {
        ctx->callbacks.init_context(ctx);
    }
 
    /* From now, the context is successfully created.
     * When it is destroyed, the exit callback should be called. */
    ctx->callbacks.exit_context = exit_callback;
    ctx->context_type = CONTEXT_SERVER; /* server context */
 
    /* Start worker threads */
    for (i = 0; i < ctx->cfg_worker_threads; i++) {
        /* worker_thread sets up the other fields */
        ctx->worker_connections[i].phys_ctx = ctx;
        if (mg_start_thread_with_id(worker_thread,
                                    &ctx->worker_connections[i],
                                    &ctx->worker_threadids[i])
            != 0) {
 
            long error_no = (long)ERRNO;
 
            /* thread was not created */
            if (i > 0) {
                /* If the second, third, ... thread cannot be created, set a
                 * warning, but keep running. */
                mg_cry_ctx_internal(ctx,
                                    "Cannot start worker thread %i: error %ld",
                                    i + 1,
                                    error_no);
 
                /* If the server initialization should stop here, all
                 * threads that have already been created must be stopped
                 * first, before any free_context(ctx) call.
                 */
 
            } else {
                /* If the first worker thread cannot be created, stop
                 * initialization and free the entire server context. */
                mg_cry_ctx_internal(ctx,
                                    "Cannot create threads: error %ld",
                                    error_no);
 
                if (error != NULL) {
                    error->code = MG_ERROR_DATA_CODE_OS_ERROR;
                    error->code_sub = (unsigned)error_no;
                    mg_snprintf(
                        NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Cannot create first worker thread: error %ld",
                        error_no);
                }
 
                free_context(ctx);
                pthread_setspecific(sTlsKey, NULL);
                return NULL;
            }
            break;
        }
    }
 
    /* Start master (listening) thread */
    mg_start_thread_with_id(master_thread, ctx, &ctx->masterthreadid);
 
    pthread_setspecific(sTlsKey, NULL);
    return ctx;
}
 
 
CIVETWEB_API struct mg_context *
mg_start(const struct mg_callbacks *callbacks,
         void *user_data,
         const char **options)
{
    struct mg_init_data init = {0};
    init.callbacks = callbacks;
    init.user_data = user_data;
    init.configuration_options = options;
 
    return mg_start2(&init, NULL);
}
 
 
/* Add an additional domain to an already running web server. */
CIVETWEB_API int
mg_start_domain2(struct mg_context *ctx,
                 const char **options,
                 struct mg_error_data *error)
{
    const char *name;
    const char *value;
    const char *default_value;
    struct mg_domain_context *new_dom;
    struct mg_domain_context *dom;
    int idx, i;
 
    if (error != NULL) {
        error->code = MG_ERROR_DATA_CODE_OK;
        error->code_sub = 0;
        if (error->text_buffer_size > 0) {
            *error->text = 0;
        }
    }
 
    if ((ctx == NULL) || (options == NULL)) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INVALID_PARAM;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "Invalid parameters");
        }
        return -1;
    }
 
    if (!STOP_FLAG_IS_ZERO(&ctx->stop_flag)) {
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_SERVER_STOPPED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "Server already stopped");
        }
        return -7;
    }
 
    new_dom = (struct mg_domain_context *)
        mg_calloc_ctx(1, sizeof(struct mg_domain_context), ctx);
 
    if (!new_dom) {
        /* Out of memory */
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_OUT_OF_MEMORY;
            error->code_sub = (unsigned)sizeof(struct mg_domain_context);
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "Out or memory");
        }
        return -6;
    }
 
    /* Store options - TODO: unite duplicate code */
    while (options && (name = *options++) != NULL) {
        idx = get_option_index(name);
        if (idx == -1) {
            mg_cry_ctx_internal(ctx, "Invalid option: %s", name);
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
                error->code_sub = (unsigned)-1;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            "Invalid option: %s",
                            name);
            }
            mg_free(new_dom);
            return -2;
        } else if ((value = *options++) == NULL) {
            mg_cry_ctx_internal(ctx, "%s: option value cannot be NULL", name);
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_INVALID_OPTION;
                error->code_sub = (unsigned)idx;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            "Invalid option value: %s",
                            name);
            }
            mg_free(new_dom);
            return -2;
        }
        if (new_dom->config[idx] != NULL) {
            /* Duplicate option: Later values overwrite earlier ones. */
            mg_cry_ctx_internal(ctx, "warning: %s: duplicate option", name);
            mg_free(new_dom->config[idx]);
        }
        new_dom->config[idx] = mg_strdup_ctx(value, ctx);
        DEBUG_TRACE("[%s] -> [%s]", name, value);
    }
 
    /* Authentication domain is mandatory */
    /* TODO: Maybe use a new option hostname? */
    if (!new_dom->config[AUTHENTICATION_DOMAIN]) {
        mg_cry_ctx_internal(ctx, "%s", "authentication domain required");
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_MISSING_OPTION;
            error->code_sub = AUTHENTICATION_DOMAIN;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "Mandatory option %s missing",
                        config_options[AUTHENTICATION_DOMAIN].name);
        }
        mg_free(new_dom);
        return -4;
    }
 
    /* Set default value if needed. Take the config value from
     * ctx as a default value. */
    for (i = 0; config_options[i].name != NULL; i++) {
        default_value = ctx->dd.config[i];
        if ((new_dom->config[i] == NULL) && (default_value != NULL)) {
            new_dom->config[i] = mg_strdup_ctx(default_value, ctx);
        }
    }
 
    new_dom->handlers = NULL;
    new_dom->next = NULL;
    new_dom->nonce_count = 0;
    new_dom->auth_nonce_mask = get_random() ^ (get_random() << 31);
 
#if defined(USE_LUA) && defined(USE_WEBSOCKET)
    new_dom->shared_lua_websockets = NULL;
#endif
 
#if !defined(NO_SSL) && !defined(USE_MBEDTLS)
    if (!init_ssl_ctx(ctx, new_dom)) {
        /* Init SSL failed */
        if (error != NULL) {
            error->code = MG_ERROR_DATA_CODE_INIT_TLS_FAILED;
            mg_snprintf(NULL,
                        NULL, /* No truncation check for error buffers */
                        error->text,
                        error->text_buffer_size,
                        "%s",
                        "Initializing SSL context failed");
        }
        mg_free(new_dom);
        return -3;
    }
#endif
 
    /* Add element to linked list. */
    mg_lock_context(ctx);
 
    idx = 0;
    dom = &(ctx->dd);
    for (;;) {
        if (!mg_strcasecmp(new_dom->config[AUTHENTICATION_DOMAIN],
                           dom->config[AUTHENTICATION_DOMAIN])) {
            /* Domain collision */
            mg_cry_ctx_internal(ctx,
                                "domain %s already in use",
                                new_dom->config[AUTHENTICATION_DOMAIN]);
            if (error != NULL) {
                error->code = MG_ERROR_DATA_CODE_DUPLICATE_DOMAIN;
                mg_snprintf(NULL,
                            NULL, /* No truncation check for error buffers */
                            error->text,
                            error->text_buffer_size,
                            "Domain %s specified by %s is already in use",
                            new_dom->config[AUTHENTICATION_DOMAIN],
                            config_options[AUTHENTICATION_DOMAIN].name);
            }
            mg_free(new_dom);
            mg_unlock_context(ctx);
            return -5;
        }
 
        /* Count number of domains */
        idx++;
 
        if (dom->next == NULL) {
            dom->next = new_dom;
            break;
        }
        dom = dom->next;
    }
 
    mg_unlock_context(ctx);
 
    /* Return domain number */
    return idx;
}
 
 
CIVETWEB_API int
mg_start_domain(struct mg_context *ctx, const char **options)
{
    return mg_start_domain2(ctx, options, NULL);
}
 
 
/* Feature check API function */
CIVETWEB_API unsigned
mg_check_feature(unsigned feature)
{
    static const unsigned feature_set = 0
    /* Set bits for available features according to API documentation.
     * This bit mask is created at compile time, according to the active
     * preprocessor defines. It is a single const value at runtime. */
#if !defined(NO_FILES)
                                        | MG_FEATURES_FILES
#endif
#if !defined(NO_SSL) || defined(USE_MBEDTLS)
                                        | MG_FEATURES_SSL
#endif
#if !defined(NO_CGI)
                                        | MG_FEATURES_CGI
#endif
#if defined(USE_IPV6)
                                        | MG_FEATURES_IPV6
#endif
#if defined(USE_WEBSOCKET)
                                        | MG_FEATURES_WEBSOCKET
#endif
#if defined(USE_LUA)
                                        | MG_FEATURES_LUA
#endif
#if defined(USE_DUKTAPE)
                                        | MG_FEATURES_SSJS
#endif
#if !defined(NO_CACHING)
                                        | MG_FEATURES_CACHE
#endif
#if defined(USE_SERVER_STATS)
                                        | MG_FEATURES_STATS
#endif
#if defined(USE_ZLIB)
                                        | MG_FEATURES_COMPRESSION
#endif
#if defined(USE_HTTP2)
                                        | MG_FEATURES_HTTP2
#endif
#if defined(USE_X_DOM_SOCKET)
                                        | MG_FEATURES_X_DOMAIN_SOCKET
#endif
 
    /* Set some extra bits not defined in the API documentation.
     * These bits may change without further notice. */
#if defined(MG_LEGACY_INTERFACE)
                                        | 0x80000000u
#endif
#if defined(MG_EXPERIMENTAL_INTERFACES)
                                        | 0x40000000u
#endif
#if !defined(NO_RESPONSE_BUFFERING)
                                        | 0x20000000u
#endif
#if defined(MEMORY_DEBUGGING)
                                        | 0x10000000u
#endif
        ;
    return (feature & feature_set);
}
 
 
static size_t
mg_str_append(char **dst, char *end, const char *src)
{
    size_t len = strlen(src);
    if (*dst != end) {
        /* Append src if enough space, or close dst. */
        if ((size_t)(end - *dst) > len) {
            strcpy(*dst, src);
            *dst += len;
        } else {
            *dst = end;
        }
    }
    return len;
}
 
 
/* Get system information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_system_info(char *buffer, int buflen)
{
    char *end, *append_eoobj = NULL, block[256];
    size_t system_info_length = 0;
 
#if defined(_WIN32)
    static const char eol[] = "\r\n", eoobj[] = "\r\n}\r\n";
#else
    static const char eol[] = "\n", eoobj[] = "\n}\n";
#endif
 
    if ((buffer == NULL) || (buflen < 1)) {
        buflen = 0;
        end = buffer;
    } else {
        *buffer = 0;
        end = buffer + buflen;
    }
    if (buflen > (int)(sizeof(eoobj) - 1)) {
        /* has enough space to append eoobj */
        append_eoobj = buffer;
        if (end) {
            end -= sizeof(eoobj) - 1;
        }
    }
 
    system_info_length += mg_str_append(&buffer, end, "{");
 
    /* Server version */
    {
        const char *version = mg_version();
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    "%s\"version\" : \"%s\"",
                    eol,
                    version);
        system_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* System info */
    {
#if defined(_WIN32)
        DWORD dwVersion = 0;
        DWORD dwMajorVersion = 0;
        DWORD dwMinorVersion = 0;
        SYSTEM_INFO si;
 
        GetSystemInfo(&si);
 
#if defined(_MSC_VER)
#pragma warning(push)
        /* GetVersion was declared deprecated */
#pragma warning(disable : 4996)
#endif
        dwVersion = GetVersion();
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
 
        dwMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
        dwMinorVersion = (DWORD)(HIBYTE(LOWORD(dwVersion)));
 
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"os\" : \"Windows %u.%u\"",
                    eol,
                    (unsigned)dwMajorVersion,
                    (unsigned)dwMinorVersion);
        system_info_length += mg_str_append(&buffer, end, block);
 
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"cpu\" : \"type %u, cores %u, mask %x\"",
                    eol,
                    (unsigned)si.wProcessorArchitecture,
                    (unsigned)si.dwNumberOfProcessors,
                    (unsigned)si.dwActiveProcessorMask);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__ZEPHYR__)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"os\" : \"%s %s\"",
                    eol,
                    "Zephyr OS",
                    ZEPHYR_VERSION);
        system_info_length += mg_str_append(&buffer, end, block);
#else
        struct utsname name;
        memset(&name, 0, sizeof(name));
        uname(&name);
 
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"os\" : \"%s %s (%s) - %s\"",
                    eol,
                    name.sysname,
                    name.version,
                    name.release,
                    name.machine);
        system_info_length += mg_str_append(&buffer, end, block);
#endif
    }
 
    /* Features */
    {
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"features\" : %lu"
                    ",%s\"feature_list\" : \"Server:%s%s%s%s%s%s%s%s%s\"",
                    eol,
                    (unsigned long)mg_check_feature(0xFFFFFFFFu),
                    eol,
                    mg_check_feature(MG_FEATURES_FILES) ? " Files" : "",
                    mg_check_feature(MG_FEATURES_SSL) ? " HTTPS" : "",
                    mg_check_feature(MG_FEATURES_CGI) ? " CGI" : "",
                    mg_check_feature(MG_FEATURES_IPV6) ? " IPv6" : "",
                    mg_check_feature(MG_FEATURES_WEBSOCKET) ? " WebSockets"
                                                            : "",
                    mg_check_feature(MG_FEATURES_LUA) ? " Lua" : "",
                    mg_check_feature(MG_FEATURES_SSJS) ? " JavaScript" : "",
                    mg_check_feature(MG_FEATURES_CACHE) ? " Cache" : "",
                    mg_check_feature(MG_FEATURES_STATS) ? " Stats" : "");
        system_info_length += mg_str_append(&buffer, end, block);
 
#if defined(USE_LUA)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"lua_version\" : \"%u (%s)\"",
                    eol,
                    (unsigned)LUA_VERSION_NUM,
                    LUA_RELEASE);
        system_info_length += mg_str_append(&buffer, end, block);
#endif
#if defined(USE_DUKTAPE)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"javascript\" : \"Duktape %u.%u.%u\"",
                    eol,
                    (unsigned)DUK_VERSION / 10000,
                    ((unsigned)DUK_VERSION / 100) % 100,
                    (unsigned)DUK_VERSION % 100);
        system_info_length += mg_str_append(&buffer, end, block);
#endif
    }
 
    /* Build identifier. If BUILD_DATE is not set, __DATE__ will be used. */
    {
#if defined(BUILD_DATE)
        const char *bd = BUILD_DATE;
#else
#if defined(GCC_DIAGNOSTIC)
#if GCC_VERSION >= 40900
#pragma GCC diagnostic push
        /* Disable idiotic compiler warning -Wdate-time, appeared in gcc5. This
         * does not work in some versions. If "BUILD_DATE" is defined to some
         * string, it is used instead of __DATE__. */
#pragma GCC diagnostic ignored "-Wdate-time"
#endif
#endif
        const char *bd = __DATE__;
#if defined(GCC_DIAGNOSTIC)
#if GCC_VERSION >= 40900
#pragma GCC diagnostic pop
#endif
#endif
#endif
 
        mg_snprintf(
            NULL, NULL, block, sizeof(block), ",%s\"build\" : \"%s\"", eol, bd);
 
        system_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* Compiler information */
    /* http://sourceforge.net/p/predef/wiki/Compilers/ */
    {
#if defined(_MSC_VER)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"MSC: %u (%u)\"",
                    eol,
                    (unsigned)_MSC_VER,
                    (unsigned)_MSC_FULL_VER);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__MINGW64__)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"MinGW64: %u.%u\"",
                    eol,
                    (unsigned)__MINGW64_VERSION_MAJOR,
                    (unsigned)__MINGW64_VERSION_MINOR);
        system_info_length += mg_str_append(&buffer, end, block);
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"MinGW32: %u.%u\"",
                    eol,
                    (unsigned)__MINGW32_MAJOR_VERSION,
                    (unsigned)__MINGW32_MINOR_VERSION);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__MINGW32__)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"MinGW32: %u.%u\"",
                    eol,
                    (unsigned)__MINGW32_MAJOR_VERSION,
                    (unsigned)__MINGW32_MINOR_VERSION);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__clang__)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"clang: %u.%u.%u (%s)\"",
                    eol,
                    __clang_major__,
                    __clang_minor__,
                    __clang_patchlevel__,
                    __clang_version__);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__GNUC__)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"gcc: %u.%u.%u\"",
                    eol,
                    (unsigned)__GNUC__,
                    (unsigned)__GNUC_MINOR__,
                    (unsigned)__GNUC_PATCHLEVEL__);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__INTEL_COMPILER)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"Intel C/C++: %u\"",
                    eol,
                    (unsigned)__INTEL_COMPILER);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__BORLANDC__)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"Borland C: 0x%x\"",
                    eol,
                    (unsigned)__BORLANDC__);
        system_info_length += mg_str_append(&buffer, end, block);
#elif defined(__SUNPRO_C)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"Solaris: 0x%x\"",
                    eol,
                    (unsigned)__SUNPRO_C);
        system_info_length += mg_str_append(&buffer, end, block);
#else
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"compiler\" : \"other\"",
                    eol);
        system_info_length += mg_str_append(&buffer, end, block);
#endif
    }
 
    /* Determine 32/64 bit data mode.
     * see https://en.wikipedia.org/wiki/64-bit_computing */
    {
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"data_model\" : \"int:%u/%u/%u/%u, float:%u/%u/%u, "
                    "char:%u/%u, "
                    "ptr:%u, size:%u, time:%u\"",
                    eol,
                    (unsigned)sizeof(short),
                    (unsigned)sizeof(int),
                    (unsigned)sizeof(long),
                    (unsigned)sizeof(long long),
                    (unsigned)sizeof(float),
                    (unsigned)sizeof(double),
                    (unsigned)sizeof(long double),
                    (unsigned)sizeof(char),
                    (unsigned)sizeof(wchar_t),
                    (unsigned)sizeof(void *),
                    (unsigned)sizeof(size_t),
                    (unsigned)sizeof(time_t));
        system_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* Terminate string */
    if (append_eoobj) {
        strcat(append_eoobj, eoobj);
    }
    system_info_length += sizeof(eoobj) - 1;
 
    return (int)system_info_length;
}
 
 
/* Get context information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_context_info(const struct mg_context *ctx, char *buffer, int buflen)
{
#if defined(USE_SERVER_STATS)
    char *end, *append_eoobj = NULL, block[256];
    size_t context_info_length = 0;
 
#if defined(_WIN32)
    static const char eol[] = "\r\n", eoobj[] = "\r\n}\r\n";
#else
    static const char eol[] = "\n", eoobj[] = "\n}\n";
#endif
    struct mg_memory_stat *ms = get_memory_stat((struct mg_context *)ctx);
 
    if ((buffer == NULL) || (buflen < 1)) {
        buflen = 0;
        end = buffer;
    } else {
        *buffer = 0;
        end = buffer + buflen;
    }
    if (buflen > (int)(sizeof(eoobj) - 1)) {
        /* has enough space to append eoobj */
        append_eoobj = buffer;
        end -= sizeof(eoobj) - 1;
    }
 
    context_info_length += mg_str_append(&buffer, end, "{");
 
    if (ms) { /* <-- should be always true */
              /* Memory information */
        int blockCount = (int)ms->blockCount;
        int64_t totalMemUsed = ms->totalMemUsed;
        int64_t maxMemUsed = ms->maxMemUsed;
        if (totalMemUsed > maxMemUsed) {
            maxMemUsed = totalMemUsed;
        }
 
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    "%s\"memory\" : {%s"
                    "\"blocks\" : %i,%s"
                    "\"used\" : %" INT64_FMT ",%s"
                    "\"maxUsed\" : %" INT64_FMT "%s"
                    "}",
                    eol,
                    eol,
                    blockCount,
                    eol,
                    totalMemUsed,
                    eol,
                    maxMemUsed,
                    eol);
        context_info_length += mg_str_append(&buffer, end, block);
    }
 
    if (ctx) {
        /* Declare all variables at begin of the block, to comply
         * with old C standards. */
        char start_time_str[64] = {0};
        char now_str[64] = {0};
        time_t start_time = ctx->start_time;
        time_t now = time(NULL);
        int64_t total_data_read, total_data_written;
        int active_connections = (int)ctx->active_connections;
        int max_active_connections = (int)ctx->max_active_connections;
        int total_connections = (int)ctx->total_connections;
        if (active_connections > max_active_connections) {
            max_active_connections = active_connections;
        }
        if (active_connections > total_connections) {
            total_connections = active_connections;
        }
 
        /* Connections information */
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"connections\" : {%s"
                    "\"active\" : %i,%s"
                    "\"maxActive\" : %i,%s"
                    "\"total\" : %i%s"
                    "}",
                    eol,
                    eol,
                    active_connections,
                    eol,
                    max_active_connections,
                    eol,
                    total_connections,
                    eol);
        context_info_length += mg_str_append(&buffer, end, block);
 
        /* Queue information */
#if !defined(ALTERNATIVE_QUEUE)
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"queue\" : {%s"
                    "\"length\" : %i,%s"
                    "\"filled\" : %i,%s"
                    "\"maxFilled\" : %i,%s"
                    "\"full\" : %s%s"
                    "}",
                    eol,
                    eol,
                    ctx->sq_size,
                    eol,
                    ctx->sq_head - ctx->sq_tail,
                    eol,
                    ctx->sq_max_fill,
                    eol,
                    (ctx->sq_blocked ? "true" : "false"),
                    eol);
        context_info_length += mg_str_append(&buffer, end, block);
#endif
 
        /* Requests information */
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"requests\" : {%s"
                    "\"total\" : %lu%s"
                    "}",
                    eol,
                    eol,
                    (unsigned long)ctx->total_requests,
                    eol);
        context_info_length += mg_str_append(&buffer, end, block);
 
        /* Data information */
        total_data_read =
            mg_atomic_add64((volatile int64_t *)&ctx->total_data_read, 0);
        total_data_written =
            mg_atomic_add64((volatile int64_t *)&ctx->total_data_written, 0);
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"data\" : {%s"
                    "\"read\" : %" INT64_FMT ",%s"
                    "\"written\" : %" INT64_FMT "%s"
                    "}",
                    eol,
                    eol,
                    total_data_read,
                    eol,
                    total_data_written,
                    eol);
        context_info_length += mg_str_append(&buffer, end, block);
 
        /* Execution time information */
        gmt_time_string(start_time_str,
                        sizeof(start_time_str) - 1,
                        &start_time);
        gmt_time_string(now_str, sizeof(now_str) - 1, &now);
 
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    ",%s\"time\" : {%s"
                    "\"uptime\" : %.0f,%s"
                    "\"start\" : \"%s\",%s"
                    "\"now\" : \"%s\"%s"
                    "}",
                    eol,
                    eol,
                    difftime(now, start_time),
                    eol,
                    start_time_str,
                    eol,
                    now_str,
                    eol);
        context_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* Terminate string */
    if (append_eoobj) {
        strcat(append_eoobj, eoobj);
    }
    context_info_length += sizeof(eoobj) - 1;
 
    return (int)context_info_length;
#else
    (void)ctx;
    if ((buffer != NULL) && (buflen > 0)) {
        *buffer = 0;
    }
    return 0;
#endif
}
 
 
CIVETWEB_API void
mg_disable_connection_keep_alive(struct mg_connection *conn)
{
    /* https://github.com/civetweb/civetweb/issues/727 */
    if (conn != NULL) {
        conn->must_close = 1;
    }
}
 
 
#if defined(MG_EXPERIMENTAL_INTERFACES)
/* Get connection information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_connection_info(const struct mg_context *ctx,
                       int idx,
                       char *buffer,
                       int buflen)
{
    const struct mg_connection *conn;
    const struct mg_request_info *ri;
    char *end, *append_eoobj = NULL, block[256];
    size_t connection_info_length = 0;
    int state = 0;
    const char *state_str = "unknown";
 
#if defined(_WIN32)
    static const char eol[] = "\r\n", eoobj[] = "\r\n}\r\n";
#else
    static const char eol[] = "\n", eoobj[] = "\n}\n";
#endif
 
    if ((buffer == NULL) || (buflen < 1)) {
        buflen = 0;
        end = buffer;
    } else {
        *buffer = 0;
        end = buffer + buflen;
    }
    if (buflen > (int)(sizeof(eoobj) - 1)) {
        /* has enough space to append eoobj */
        append_eoobj = buffer;
        end -= sizeof(eoobj) - 1;
    }
 
    if ((ctx == NULL) || (idx < 0)) {
        /* Parameter error */
        return 0;
    }
 
    if ((unsigned)idx >= ctx->cfg_worker_threads) {
        /* Out of range */
        return 0;
    }
 
    /* Take connection [idx]. This connection is not locked in
     * any way, so some other thread might use it. */
    conn = (ctx->worker_connections) + idx;
 
    /* Initialize output string */
    connection_info_length += mg_str_append(&buffer, end, "{");
 
    /* Init variables */
    ri = &(conn->request_info);
 
#if defined(USE_SERVER_STATS)
    state = conn->conn_state;
 
    /* State as string */
    switch (state) {
    case 0:
        state_str = "undefined";
        break;
    case 1:
        state_str = "not used";
        break;
    case 2:
        state_str = "init";
        break;
    case 3:
        state_str = "ready";
        break;
    case 4:
        state_str = "processing";
        break;
    case 5:
        state_str = "processed";
        break;
    case 6:
        state_str = "to close";
        break;
    case 7:
        state_str = "closing";
        break;
    case 8:
        state_str = "closed";
        break;
    case 9:
        state_str = "done";
        break;
    }
#endif
 
    /* Connection info */
    if ((state >= 3) && (state < 9)) {
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    "%s\"connection\" : {%s"
                    "\"remote\" : {%s"
                    "\"protocol\" : \"%s\",%s"
                    "\"addr\" : \"%s\",%s"
                    "\"port\" : %u%s"
                    "},%s"
                    "\"handled_requests\" : %u%s"
                    "}",
                    eol,
                    eol,
                    eol,
                    get_proto_name(conn),
                    eol,
                    ri->remote_addr,
                    eol,
                    ri->remote_port,
                    eol,
                    eol,
                    conn->handled_requests,
                    eol);
        connection_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* Request info */
    if ((state >= 4) && (state < 6)) {
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    "%s%s\"request_info\" : {%s"
                    "\"method\" : \"%s\",%s"
                    "\"uri\" : \"%s\",%s"
                    "\"query\" : %s%s%s%s"
                    "}",
                    (connection_info_length > 1 ? "," : ""),
                    eol,
                    eol,
                    ri->request_method,
                    eol,
                    ri->request_uri,
                    eol,
                    ri->query_string ? "\"" : "",
                    ri->query_string ? ri->query_string : "null",
                    ri->query_string ? "\"" : "",
                    eol);
        connection_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* Execution time information */
    if ((state >= 2) && (state < 9)) {
        char start_time_str[64] = {0};
        char close_time_str[64] = {0};
        time_t start_time = conn->conn_birth_time;
        time_t close_time = 0;
        double time_diff;
 
        gmt_time_string(start_time_str,
                        sizeof(start_time_str) - 1,
                        &start_time);
#if defined(USE_SERVER_STATS)
        close_time = conn->conn_close_time;
#endif
        if (close_time != 0) {
            time_diff = difftime(close_time, start_time);
            gmt_time_string(close_time_str,
                            sizeof(close_time_str) - 1,
                            &close_time);
        } else {
            time_t now = time(NULL);
            time_diff = difftime(now, start_time);
            close_time_str[0] = 0; /* or use "now" ? */
        }
 
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    "%s%s\"time\" : {%s"
                    "\"uptime\" : %.0f,%s"
                    "\"start\" : \"%s\",%s"
                    "\"closed\" : \"%s\"%s"
                    "}",
                    (connection_info_length > 1 ? "," : ""),
                    eol,
                    eol,
                    time_diff,
                    eol,
                    start_time_str,
                    eol,
                    close_time_str,
                    eol);
        connection_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* Remote user name */
    if ((ri->remote_user) && (state < 9)) {
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    "%s%s\"user\" : {%s"
                    "\"name\" : \"%s\",%s"
                    "}",
                    (connection_info_length > 1 ? "," : ""),
                    eol,
                    eol,
                    ri->remote_user,
                    eol);
        connection_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* Data block */
    if (state >= 3) {
        mg_snprintf(NULL,
                    NULL,
                    block,
                    sizeof(block),
                    "%s%s\"data\" : {%s"
                    "\"read\" : %" INT64_FMT ",%s"
                    "\"written\" : %" INT64_FMT "%s"
                    "}",
                    (connection_info_length > 1 ? "," : ""),
                    eol,
                    eol,
                    conn->consumed_content,
                    eol,
                    conn->num_bytes_sent,
                    eol);
        connection_info_length += mg_str_append(&buffer, end, block);
    }
 
    /* State */
    mg_snprintf(NULL,
                NULL,
                block,
                sizeof(block),
                "%s%s\"state\" : \"%s\"",
                (connection_info_length > 1 ? "," : ""),
                eol,
                state_str);
    connection_info_length += mg_str_append(&buffer, end, block);
 
    /* Terminate string */
    if (append_eoobj) {
        strcat(append_eoobj, eoobj);
    }
    connection_info_length += sizeof(eoobj) - 1;
 
    return (int)connection_info_length;
}
 
#if 0
/* Get handler information. It can be printed or stored by the caller.
 * Return the size of available information. */
CIVETWEB_API int
mg_get_handler_info(struct mg_context *ctx,
                       char *buffer,
                       int buflen)
{
    int handler_info_len = 0;
    struct mg_handler_info *tmp_rh;
    mg_lock_context(ctx);
 
    for (tmp_rh = ctx->dd.handlers; tmp_rh != NULL; tmp_rh = tmp_rh->next) {
 
        if (buflen > handler_info_len+ tmp_rh->uri_len) {
        memcpy(buffer+handler_info_len, tmp_rh->uri, tmp_rh->uri_len);
        }
        handler_info_len += tmp_rh->uri_len;
 
        switch (tmp_rh->handler_type) {
            case REQUEST_HANDLER:
                (void)tmp_rh->handler;
            break;
            case WEBSOCKET_HANDLER:
        (void)tmp_rh->connect_handler;
       (void) tmp_rh->ready_handler;
       (void) tmp_rh->data_handler;
       (void) tmp_rh->close_handler;
            break;
            case AUTH_HANDLER:
             (void) tmp_rh->auth_handler;
            break;
        }
        (void)cbdata;
    }
 
    mg_unlock_context(ctx);
    return handler_info_len;
}
#endif
#endif
 
 
/* Initialize this library. This function does not need to be thread safe.
 */
CIVETWEB_API unsigned
mg_init_library(unsigned features)
{
    unsigned features_to_init = mg_check_feature(features & 0xFFu);
    unsigned features_inited = features_to_init;
 
    if (mg_init_library_called <= 0) {
        /* Not initialized yet */
        if (0 != pthread_mutex_init(&global_lock_mutex, NULL)) {
            return 0;
        }
    }
 
    mg_global_lock();
 
    if (mg_init_library_called <= 0) {
        int i;
        size_t len;
 
#if defined(_WIN32)
        int file_mutex_init = 1;
        int wsa = 1;
#else
        int mutexattr_init = 1;
#endif
        int failed = 1;
        int key_create = pthread_key_create(&sTlsKey, tls_dtor);
 
        if (key_create == 0) {
#if defined(_WIN32)
            file_mutex_init =
                pthread_mutex_init(&global_log_file_lock, &pthread_mutex_attr);
            if (file_mutex_init == 0) {
                /* Start WinSock */
                WSADATA data;
                failed = wsa = WSAStartup(MAKEWORD(2, 2), &data);
            }
#else
            mutexattr_init = pthread_mutexattr_init(&pthread_mutex_attr);
            if (mutexattr_init == 0) {
                failed = pthread_mutexattr_settype(&pthread_mutex_attr,
                                                   PTHREAD_MUTEX_RECURSIVE);
            }
#endif
        }
 
        if (failed) {
#if defined(_WIN32)
            if (wsa == 0) {
                (void)WSACleanup();
            }
            if (file_mutex_init == 0) {
                (void)pthread_mutex_destroy(&global_log_file_lock);
            }
#else
            if (mutexattr_init == 0) {
                (void)pthread_mutexattr_destroy(&pthread_mutex_attr);
            }
#endif
            if (key_create == 0) {
                (void)pthread_key_delete(sTlsKey);
            }
            mg_global_unlock();
            (void)pthread_mutex_destroy(&global_lock_mutex);
            return 0;
        }
 
        len = 1;
        for (i = 0; http_methods[i].name != NULL; i++) {
            size_t sl = strlen(http_methods[i].name);
            len += sl;
            if (i > 0) {
                len += 2;
            }
        }
        all_methods = (char *)mg_malloc(len);
        if (!all_methods) {
            /* Must never happen */
            mg_global_unlock();
            (void)pthread_mutex_destroy(&global_lock_mutex);
            return 0;
        }
        all_methods[0] = 0;
        for (i = 0; http_methods[i].name != NULL; i++) {
            if (i > 0) {
                strcat(all_methods, ", ");
                strcat(all_methods, http_methods[i].name);
            } else {
                strcpy(all_methods, http_methods[i].name);
            }
        }
    }
 
#if defined(USE_LUA)
    lua_init_optional_libraries();
#endif
 
#if (defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)                      \
     || defined(OPENSSL_API_3_0))                                              \
    && !defined(NO_SSL)
 
    if (features_to_init & MG_FEATURES_SSL) {
        if (!mg_openssl_initialized) {
            char ebuf[128];
            if (initialize_openssl(ebuf, sizeof(ebuf))) {
                mg_openssl_initialized = 1;
            } else {
                (void)ebuf;
                DEBUG_TRACE("Initializing SSL failed: %s", ebuf);
                features_inited &= ~((unsigned)(MG_FEATURES_SSL));
            }
        } else {
            /* ssl already initialized */
        }
    }
 
#endif
 
    if (mg_init_library_called <= 0) {
        mg_init_library_called = 1;
    } else {
        mg_init_library_called++;
    }
    mg_global_unlock();
 
    return features_inited;
}
 
 
/* Un-initialize this library. */
CIVETWEB_API unsigned
mg_exit_library(void)
{
    if (mg_init_library_called <= 0) {
        return 0;
    }
 
    mg_global_lock();
 
    mg_init_library_called--;
    if (mg_init_library_called == 0) {
#if (defined(OPENSSL_API_1_0) || defined(OPENSSL_API_1_1)) && !defined(NO_SSL)
        if (mg_openssl_initialized) {
            uninitialize_openssl();
            mg_openssl_initialized = 0;
        }
#endif
 
#if defined(_WIN32)
        (void)WSACleanup();
        (void)pthread_mutex_destroy(&global_log_file_lock);
#else
        (void)pthread_mutexattr_destroy(&pthread_mutex_attr);
#endif
 
        (void)pthread_key_delete(sTlsKey);
 
#if defined(USE_LUA)
        lua_exit_optional_libraries();
#endif
        mg_free(all_methods);
        all_methods = NULL;
 
        mg_global_unlock();
        (void)pthread_mutex_destroy(&global_lock_mutex);
        return 1;
    }
 
    mg_global_unlock();
    return 1;
}
 
 
/* End of civetweb.c */