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 // 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.
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
 #if defined(__rtems__)
 #include <md5.h>
 #define HAVE_MD5
 #define NO_CGI
 #define NO_POPEN
 #define NO_SSL
 #define USE_WEBSOCKET
 #endif // __rtems__
 
 #if defined(_WIN32)
 #if !defined(_CRT_SECURE_NO_WARNINGS)
 #define _CRT_SECURE_NO_WARNINGS // Disable deprecation warning in VS2005
 #endif
 #else
 #ifdef __linux__
 #define _XOPEN_SOURCE 600     // For flockfile() on Linux
 #endif
 #define _LARGEFILE_SOURCE     // Enable 64-bit file offsets
 #define __STDC_FORMAT_MACROS  // <inttypes.h> wants this for C++
 #define __STDC_LIMIT_MACROS   // C++ wants that for INT64_MAX
 #endif
 
 #if defined (_MSC_VER)
 // 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)
 #endif
 
 // Disable WIN32_LEAN_AND_MEAN.
 // This makes windows.h always include winsock2.h
 #ifdef WIN32_LEAN_AND_MEAN
 #undef WIN32_LEAN_AND_MEAN
 #endif
 
 #if defined(__SYMBIAN32__)
 #define NO_SSL // SSL is not supported
 #define NO_CGI // CGI is not supported
 #define PATH_MAX FILENAME_MAX
 #endif // __SYMBIAN32__
 
 #ifndef _WIN32_WCE // Some ANSI #includes are not available on Windows CE
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <errno.h>
 #include <signal.h>
 #include <fcntl.h>
 #endif // !_WIN32_WCE
 
 #include <time.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include <assert.h>
 #include <string.h>
 #include <ctype.h>
 #include <limits.h>
 #include <stddef.h>
 #include <stdio.h>
 
 #if __rtems__
 #include <time.h>
 #include <sys/param.h>
 #include <rtems/libio_.h>
 #endif
 
 #if defined(_WIN32) && !defined(__SYMBIAN32__) // Windows specific
 #undef _WIN32_WINNT
 #define _WIN32_WINNT 0x0400 // To make it link in VS2005
 #include <windows.h>
 
 #ifndef PATH_MAX
 #define PATH_MAX MAX_PATH
 #endif
 
 #ifndef _WIN32_WCE
 #include <process.h>
 #include <direct.h>
 #include <io.h>
 #else // _WIN32_WCE
 #define NO_CGI // WinCE has no pipes
 
 typedef long off_t;
 
 #define errno   GetLastError()
 #define strerror(x)  _ultoa(x, (char *) _alloca(sizeof(x) *3 ), 10)
 #endif // _WIN32_WCE
 
 #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) && _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 // _MSC_VER
 
 #define ERRNO   GetLastError()
 #define NO_SOCKLEN_T
 #define SSL_LIB   "ssleay32.dll"
 #define CRYPTO_LIB  "libeay32.dll"
 #define O_NONBLOCK  0
 #if !defined(EWOULDBLOCK)
 #define EWOULDBLOCK  WSAEWOULDBLOCK
 #endif // !EWOULDBLOCK
 #define _POSIX_
 #define INT64_FMT  "I64d"
 
 #define WINCDECL __cdecl
 #define SHUT_WR 1
 #define snprintf _snprintf
 #define vsnprintf _vsnprintf
 #define mg_sleep(x) Sleep(x)
 
 #define pipe(x) _pipe(x, MG_BUF_LEN, _O_BINARY)
 #ifndef popen
 #define popen(x, y) _popen(x, y)
 #endif
 #ifndef 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))
 #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) EnterCriticalSection(&global_log_file_lock)
 #define funlockfile(x) LeaveCriticalSection(&global_log_file_lock)
 #define sleep(x) Sleep((x) * 1000)
 #define rmdir(x) _rmdir(x)
 
 #if !defined(va_copy)
 #define va_copy(x, y) x = y
 #endif // !va_copy MINGW #defines va_copy
 
 #if !defined(fileno)
 #define fileno(x) _fileno(x)
 #endif // !fileno MINGW #defines fileno
 
 typedef HANDLE pthread_mutex_t;
 typedef struct {HANDLE signal, broadcast;} pthread_cond_t;
 typedef DWORD pthread_t;
 #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 to_unicode(const char *path, wchar_t *wbuf, size_t wbuf_len);
 struct file;
 static char *mg_fgets(char *buf, size_t size, struct file *filep, char **p);
 
 #if defined(HAVE_STDINT)
 #include <stdint.h>
 #else
 typedef unsigned int  uint32_t;
 typedef unsigned short  uint16_t;
 typedef unsigned __int64 uint64_t;
 typedef __int64   int64_t;
 #define INT64_MAX  9223372036854775807
 #endif // HAVE_STDINT
 
 // POSIX dirent interface
 struct dirent {
   char d_name[PATH_MAX];
 };
 
 typedef struct DIR {
   HANDLE   handle;
   WIN32_FIND_DATAW info;
   struct dirent  result;
 } DIR;
 
 
 // Mark required libraries
 #ifdef _MSC_VER
 #pragma comment(lib, "Ws2_32.lib")
 #endif
 
 #else    // UNIX  specific
 #include <sys/wait.h>
 #include <sys/socket.h>
 #include <sys/select.h>
 #ifdef HAVE_POLL
 #include <sys/poll.h>
 #endif
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <sys/time.h>
 #include <stdint.h>
 #include <inttypes.h>
 #include <netdb.h>
 
 #include <pwd.h>
 #include <unistd.h>
 #include <dirent.h>
 #if !defined(NO_SSL_DL) && !defined(NO_SSL)
 #include <dlfcn.h>
 #endif
 #include <pthread.h>
 #if defined(__MACH__)
 #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
 #ifndef O_BINARY
 #define O_BINARY  0
 #endif // O_BINARY
 #define closesocket(a) close(a)
 #define mg_mkdir(x, y) mkdir(x, y)
 #define mg_remove(x) remove(x)
 #define mg_sleep(x) usleep((x) * 1000)
 #define ERRNO errno
 #define INVALID_SOCKET (-1)
 #define INT64_FMT PRId64
 typedef int SOCKET;
 #define WINCDECL
 
 #endif // End of Windows and UNIX specific includes
 
 #ifndef HAVE_POLL
 struct pollfd {
   SOCKET fd;
   short events;
   short revents;
 };
 #define POLLIN 1
 #endif
 
 #include <mghttpd/mongoose.h>
 
 #define MONGOOSE_VERSION "3.9"
 #define PASSWORDS_FILE_NAME ".htpasswd"
 #define CGI_ENVIRONMENT_SIZE 4096
 #define MAX_CGI_ENVIR_VARS 64
 #define MG_BUF_LEN 8192
 #define MAX_REQUEST_SIZE 16384
 #define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
 
 #ifdef _WIN32
 static CRITICAL_SECTION global_log_file_lock;
 static pthread_t pthread_self(void) {
   return GetCurrentThreadId();
 }
 #endif // _WIN32
 
 #ifdef DEBUG_TRACE
 #undef DEBUG_TRACE
 #define DEBUG_TRACE(x)
 #else
 #if defined(DEBUG)
 #define DEBUG_TRACE(x) do { \
   flockfile(stdout); \
   printf("*** %lu.%p.%s.%d: ", \
          (unsigned long) time(NULL), (void *) pthread_self(), \
          __func__, __LINE__); \
   printf x; \
   putchar('\n'); \
   fflush(stdout); \
   funlockfile(stdout); \
 } while (0)
 #else
 #define DEBUG_TRACE(x)
 #endif // DEBUG
 #endif // DEBUG_TRACE
 
 // Darwin prior to 7.0 and Win32 do not have socklen_t
 #ifdef NO_SOCKLEN_T
 typedef int socklen_t;
 #endif // NO_SOCKLEN_T
 #define _DARWIN_UNLIMITED_SELECT
 
 #define IP_ADDR_STR_LEN 50  // IPv6 hex string is 46 chars
 
 #if !defined(MSG_NOSIGNAL)
 #define MSG_NOSIGNAL 0
 #endif
 
 #if !defined(SOMAXCONN)
 #define SOMAXCONN 100
 #endif
 
 #if !defined(PATH_MAX)
 #define PATH_MAX 4096
 #endif
 
 // Size of the accepted socket queue
 #if !defined(MGSQLEN)
 #define MGSQLEN 20
 #endif
 
 static const char *http_500_error = "Internal Server Error";
 
 #if defined(NO_SSL_DL)
 #include <openssl/ssl.h>
 #include <openssl/err.h>
 #else
 // SSL loaded dynamically from DLL.
 // I put the prototypes here to be independent from OpenSSL source installation.
 typedef struct ssl_st SSL;
 typedef struct ssl_method_st SSL_METHOD;
 typedef struct ssl_ctx_st SSL_CTX;
 
 struct ssl_func {
   const char *name;   // SSL function name
   void  (*ptr)(void); // Function pointer
 };
 
 #define SSL_free (* (void (*)(SSL *)) ssl_sw[0].ptr)
 #define SSL_accept (* (int (*)(SSL *)) ssl_sw[1].ptr)
 #define SSL_connect (* (int (*)(SSL *)) ssl_sw[2].ptr)
 #define SSL_read (* (int (*)(SSL *, void *, int)) ssl_sw[3].ptr)
 #define SSL_write (* (int (*)(SSL *, const void *,int)) ssl_sw[4].ptr)
 #define SSL_get_error (* (int (*)(SSL *, int)) ssl_sw[5].ptr)
 #define SSL_set_fd (* (int (*)(SSL *, SOCKET)) ssl_sw[6].ptr)
 #define SSL_new (* (SSL * (*)(SSL_CTX *)) ssl_sw[7].ptr)
 #define SSL_CTX_new (* (SSL_CTX * (*)(SSL_METHOD *)) ssl_sw[8].ptr)
 #define SSLv23_server_method (* (SSL_METHOD * (*)(void)) ssl_sw[9].ptr)
 #define SSL_library_init (* (int (*)(void)) ssl_sw[10].ptr)
 #define SSL_CTX_use_PrivateKey_file (* (int (*)(SSL_CTX *, \
         const char *, int)) ssl_sw[11].ptr)
 #define SSL_CTX_use_certificate_file (* (int (*)(SSL_CTX *, \
         const char *, int)) ssl_sw[12].ptr)
 #define SSL_CTX_set_default_passwd_cb \
   (* (void (*)(SSL_CTX *, mg_callback_t)) ssl_sw[13].ptr)
 #define SSL_CTX_free (* (void (*)(SSL_CTX *)) ssl_sw[14].ptr)
 #define SSL_load_error_strings (* (void (*)(void)) ssl_sw[15].ptr)
 #define SSL_CTX_use_certificate_chain_file \
   (* (int (*)(SSL_CTX *, const char *)) ssl_sw[16].ptr)
 #define SSLv23_client_method (* (SSL_METHOD * (*)(void)) ssl_sw[17].ptr)
 #define SSL_pending (* (int (*)(SSL *)) ssl_sw[18].ptr)
 #define SSL_CTX_set_verify (* (void (*)(SSL_CTX *, int, int)) ssl_sw[19].ptr)
 #define SSL_shutdown (* (int (*)(SSL *)) ssl_sw[20].ptr)
 
 #define CRYPTO_num_locks (* (int (*)(void)) crypto_sw[0].ptr)
 #define CRYPTO_set_locking_callback \
   (* (void (*)(void (*)(int, int, const char *, int))) crypto_sw[1].ptr)
 #define CRYPTO_set_id_callback \
   (* (void (*)(unsigned long (*)(void))) crypto_sw[2].ptr)
 #define ERR_get_error (* (unsigned long (*)(void)) crypto_sw[3].ptr)
 #define ERR_error_string (* (char * (*)(unsigned long,char *)) crypto_sw[4].ptr)
 
 // set_ssl_option() function updates this array.
 // It loads SSL library dynamically and changes NULLs to the actual addresses
 // of respective functions. The macros above (like SSL_connect()) are really
 // just calling these functions indirectly via the pointer.
 static struct ssl_func ssl_sw[] = {
   {"SSL_free",   NULL},
   {"SSL_accept",   NULL},
   {"SSL_connect",   NULL},
   {"SSL_read",   NULL},
   {"SSL_write",   NULL},
   {"SSL_get_error",  NULL},
   {"SSL_set_fd",   NULL},
   {"SSL_new",   NULL},
   {"SSL_CTX_new",   NULL},
   {"SSLv23_server_method", NULL},
   {"SSL_library_init",  NULL},
   {"SSL_CTX_use_PrivateKey_file", NULL},
   {"SSL_CTX_use_certificate_file",NULL},
   {"SSL_CTX_set_default_passwd_cb",NULL},
   {"SSL_CTX_free",  NULL},
   {"SSL_load_error_strings", NULL},
   {"SSL_CTX_use_certificate_chain_file", NULL},
   {"SSLv23_client_method", NULL},
   {"SSL_pending", NULL},
   {"SSL_CTX_set_verify", NULL},
   {"SSL_shutdown",   NULL},
   {NULL,    NULL}
 };
 
 // Similar array as ssl_sw. These functions could be located in different lib.
 #if !defined(NO_SSL)
 static struct ssl_func crypto_sw[] = {
   {"CRYPTO_num_locks",  NULL},
   {"CRYPTO_set_locking_callback", NULL},
   {"CRYPTO_set_id_callback", NULL},
   {"ERR_get_error",  NULL},
   {"ERR_error_string", NULL},
   {NULL,    NULL}
 };
 #endif // NO_SSL
 #endif // NO_SSL_DL
 
 static const char *month_names[] = {
   "Jan", "Feb", "Mar", "Apr", "May", "Jun",
   "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 };
 
 // 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
 };
 
 // Describes a string (chunk of memory).
 struct vec {
   const char *ptr;
   size_t len;
 };
 
 struct file {
   int is_directory;
   time_t modification_time;
   int64_t size;
   FILE *fp;
   const char *membuf;   // Non-NULL if file data is in memory
   // set to 1 if the content is gzipped
   // in which case we need a content-encoding: gzip header
   int gzipped;
 };
 #define STRUCT_FILE_INITIALIZER {0, 0, 0, NULL, NULL, 0}
 
 // 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 is_ssl:1;    // Is port SSL-ed
   unsigned ssl_redir:1; // Is port supposed to redirect everything to SSL port
 };
 
 // NOTE(lsm): this enum shoulds be in sync with the config_options below.
 enum {
   CGI_EXTENSIONS, CGI_ENVIRONMENT, PUT_DELETE_PASSWORDS_FILE, CGI_INTERPRETER,
   PROTECT_URI, AUTHENTICATION_DOMAIN, SSI_EXTENSIONS, THROTTLE,
   ACCESS_LOG_FILE, ENABLE_DIRECTORY_LISTING, ERROR_LOG_FILE,
   GLOBAL_PASSWORDS_FILE, INDEX_FILES, ENABLE_KEEP_ALIVE, ACCESS_CONTROL_LIST,
   EXTRA_MIME_TYPES, LISTENING_PORTS, DOCUMENT_ROOT, SSL_CERTIFICATE,
   NUM_THREADS, RUN_AS_USER, REWRITE, HIDE_FILES, REQUEST_TIMEOUT,
   THREAD_STACK_SIZE, THREAD_PRIORITY, THREAD_POLICY,
   NUM_OPTIONS
 };
 
 static const char *config_options[] = {
   "cgi_pattern", "**.cgi$|**.pl$|**.php$",
   "cgi_environment", NULL,
   "put_delete_auth_file", NULL,
   "cgi_interpreter", NULL,
   "protect_uri", NULL,
   "authentication_domain", "mydomain.com",
   "ssi_pattern", "**.shtml$|**.shtm$",
   "throttle", NULL,
   "access_log_file", NULL,
   "enable_directory_listing", "yes",
   "error_log_file", NULL,
   "global_auth_file", NULL,
   "index_files",
     "index.html,index.htm,index.cgi,index.shtml,index.php,index.lp",
   "enable_keep_alive", "no",
   "access_control_list", NULL,
   "extra_mime_types", NULL,
   "listening_ports", "8080",
   "document_root",  NULL,
   "ssl_certificate", NULL,
   "num_threads", "50",
   "run_as_user", NULL,
   "url_rewrite_patterns", NULL,
   "hide_files_patterns", NULL,
   "request_timeout_ms", "30000",
   "thread_stack_size", NULL,
   "thread_priority", NULL,
   "thread_policy", NULL,
   NULL
 };
 
 struct mg_context {
   volatile int stop_flag;         // Should we stop event loop
   SSL_CTX *ssl_ctx;               // SSL context
   char *config[NUM_OPTIONS];      // Mongoose configuration parameters
   struct mg_callbacks callbacks;  // User-defined callback function
   void *user_data;                // User-defined data
 
   struct socket *listening_sockets;
   int num_listening_sockets;
 
   volatile int num_threads;  // Number of threads
   pthread_mutex_t mutex;     // Protects (max|num)_threads
   pthread_cond_t  cond;      // Condvar for tracking workers terminations
 
   struct socket queue[MGSQLEN];   // Accepted sockets
   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
 };
 
 struct mg_connection {
   struct mg_request_info request_info;
   struct mg_context *ctx;
   SSL *ssl;                   // SSL descriptor
   SSL_CTX *client_ssl_ctx;    // SSL context for client connections
   struct socket client;       // Connected client
   time_t birth_time;          // Time when request was received
   int64_t num_bytes_sent;     // Total bytes sent to client
   int64_t content_len;        // Content-Length header value
   int64_t consumed_content;   // How many bytes of content have been 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 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
   int64_t last_throttle_bytes;// Bytes sent this second
 };
 
 // Directory entry
 struct de {
   struct mg_connection *conn;
   char *file_name;
   struct file file;
 };
 
 const char **mg_get_valid_option_names(void) {
   return config_options;
 }
 
 static int is_file_in_memory(struct mg_connection *conn, const char *path,
                              struct file *filep) {
   size_t size = 0;
   if ((filep->membuf = conn->ctx->callbacks.open_file == NULL ? NULL :
        conn->ctx->callbacks.open_file(conn, path, &size)) != NULL) {
     // NOTE: override filep->size only on success. Otherwise, it might break
     // constructs like if (!mg_stat() || !mg_fopen()) ...
     filep->size = size;
   }
   return filep->membuf != NULL;
 }
 
 static int is_file_opened(const struct file *filep) {
   return filep->membuf != NULL || filep->fp != NULL;
 }
 
 static int mg_fopen(struct mg_connection *conn, const char *path,
                     const char *mode, struct file *filep) {
   if (!is_file_in_memory(conn, path, filep)) {
 #ifdef _WIN32
     wchar_t wbuf[PATH_MAX], wmode[20];
     to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
     MultiByteToWideChar(CP_UTF8, 0, mode, -1, wmode, ARRAY_SIZE(wmode));
     filep->fp = _wfopen(wbuf, wmode);
 #else
     filep->fp = fopen(path, mode);
 #endif
   }
 
   return is_file_opened(filep);
 }
 
 static void mg_fclose(struct file *filep) {
   if (filep != NULL && filep->fp != NULL) {
     fclose(filep->fp);
   }
 }
 
 static int get_option_index(const char *name) {
   int i;
 
   for (i = 0; config_options[i * 2] != NULL; i++) {
     if (strcmp(config_options[i * 2], name) == 0) {
       return i;
     }
   }
   return -1;
 }
 
 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->config[i] == NULL) {
     return "";
   } else {
     return ctx->config[i];
   }
 }
 
 static void sockaddr_to_string(char *buf, size_t len,
                                      const union usa *usa) {
   buf[0] = '\0';
 #if defined(USE_IPV6)
   inet_ntop(usa->sa.sa_family, usa->sa.sa_family == AF_INET ?
             (void *) &usa->sin.sin_addr :
             (void *) &usa->sin6.sin6_addr, buf, len);
 #elif defined(_WIN32)
   // Only Windoze Vista (and newer) have inet_ntop()
   strncpy(buf, inet_ntoa(usa->sin.sin_addr), len);
 #else
   inet_ntop(usa->sa.sa_family, (void *) &usa->sin.sin_addr, buf, len);
 #endif
 }
 
 static void cry(struct mg_connection *conn,
                 PRINTF_FORMAT_STRING(const char *fmt), ...) PRINTF_ARGS(2, 3);
 
 // Print error message to the opened error log stream.
 static void cry(struct mg_connection *conn, const char *fmt, ...) {
   char buf[MG_BUF_LEN], src_addr[IP_ADDR_STR_LEN];
   va_list ap;
   FILE *fp;
   time_t timestamp;
 
   va_start(ap, fmt);
   (void) vsnprintf(buf, sizeof(buf), fmt, ap);
   va_end(ap);
 
   // 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->ctx->callbacks.log_message == NULL ||
       conn->ctx->callbacks.log_message(conn, buf) == 0) {
     fp = conn->ctx == NULL || conn->ctx->config[ERROR_LOG_FILE] == NULL ? NULL :
       fopen(conn->ctx->config[ERROR_LOG_FILE], "a+");
 
     if (fp != NULL) {
       flockfile(fp);
       timestamp = time(NULL);
 
       sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
       fprintf(fp, "[%010lu] [error] [client %s] ", (unsigned long) timestamp,
               src_addr);
 
       if (conn->request_info.request_method != NULL) {
         fprintf(fp, "%s %s: ", conn->request_info.request_method,
                 conn->request_info.uri);
       }
 
       fprintf(fp, "%s", buf);
       fputc('\n', fp);
       funlockfile(fp);
       fclose(fp);
     }
   }
 }
 
 // Return fake connection structure. Used for logging, if connection
 // is not applicable at the moment of logging.
 static struct mg_connection *fc(struct mg_context *ctx) {
   static struct mg_connection fake_connection;
   fake_connection.ctx = ctx;
   return &fake_connection;
 }
 
 const char *mg_version(void) {
   return MONGOOSE_VERSION;
 }
 
 struct mg_request_info *mg_get_request_info(struct mg_connection *conn) {
   return &conn->request_info;
 }
 
 static void mg_strlcpy(register char *dst, register const char *src, size_t n) {
   for (; *src != '\0' && n > 1; n--) {
     *dst++ = *src++;
   }
   *dst = '\0';
 }
 
 static int lowercase(const char *s) {
   return tolower(* (const unsigned char *) s);
 }
 
 static 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;
 }
 
 static 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(const char *ptr, size_t len) {
   char *p;
 
   if ((p = (char *) malloc(len + 1)) != NULL) {
     mg_strlcpy(p, ptr, len + 1);
   }
 
   return p;
 }
 
 static char * mg_strdup(const char *str) {
   return mg_strndup(str, strlen(str));
 }
 
 static const char *mg_strcasestr(const char *big_str, const char *small_str) {
   int i, big_len = strlen(big_str), small_len = strlen(small_str);
 
   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;
 }
 
 // Like snprintf(), but never returns negative value, or a value
 // that is larger than a supplied buffer.
 // Thanks to Adam Zeldis to pointing snprintf()-caused vulnerability
 // in his audit report.
 static int mg_vsnprintf(struct mg_connection *conn, char *buf, size_t buflen,
                         const char *fmt, va_list ap) {
   int n;
 
   if (buflen == 0)
     return 0;
 
   n = vsnprintf(buf, buflen, fmt, ap);
 
   if (n < 0) {
     cry(conn, "vsnprintf error");
     n = 0;
   } else if (n >= (int) buflen) {
     cry(conn, "truncating vsnprintf buffer: [%.*s]",
         n > 200 ? 200 : n, buf);
     n = (int) buflen - 1;
   }
   buf[n] = '\0';
 
   return n;
 }
 
 static int mg_snprintf(struct mg_connection *conn, char *buf, size_t buflen,
                        PRINTF_FORMAT_STRING(const char *fmt), ...)
   PRINTF_ARGS(4, 5);
 
 static int mg_snprintf(struct mg_connection *conn, char *buf, size_t buflen,
                        const char *fmt, ...) {
   va_list ap;
   int n;
 
   va_start(ap, fmt);
   n = mg_vsnprintf(conn, buf, buflen, fmt, ap);
   va_end(ap);
 
   return n;
 }
 
 // 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) {
       // If there is anything beyond end_word, copy it
       if (*end_word == '\0') {
 
         *p = '\0';
         break;
       } else {
         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;
       }
     }
     for (p++; p < end_word; p++) {
       *p = '\0';
     }
   }
 
   if (*end_word == '\0') {
     *buf = end_word;
   } else {
     end_whitespace = end_word + 1 + strspn(end_word + 1, whitespace);
 
     for (p = end_word; p < end_whitespace; p++) {
       *p = '\0';
     }
 
     *buf = end_whitespace;
   }
 
   return begin_word;
 }
 
 // Simplified version of skip_quoted without quote char
 // and whitespace == delimiters
 static char *skip(char **buf, const char *delimiters) {
   return skip_quoted(buf, delimiters, delimiters, 0);
 }
 
 
 // Return HTTP header value, or NULL if not found.
 static const char *get_header(const struct mg_request_info *ri,
                               const char *name) {
   int i;
 
   for (i = 0; i < ri->num_headers; i++)
     if (!mg_strcasecmp(name, ri->http_headers[i].name))
       return ri->http_headers[i].value;
 
   return NULL;
 }
 
 const char *mg_get_header(const struct mg_connection *conn, const char *name) {
   return get_header(&conn->request_info, name);
 }
 
 // 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) {
   if (list == NULL || *list == '\0') {
     // End of the list
     list = NULL;
   } else {
     val->ptr = list;
     if ((list = strchr(val->ptr, ',')) != NULL) {
       // Comma found. Store length and shift the list ptr
       val->len = list - val->ptr;
       list++;
     } else {
       // This value is the last one
       list = val->ptr + strlen(val->ptr);
       val->len = list - val->ptr;
     }
 
     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 = val->ptr + val->len - eq_val->ptr;
         val->len = (eq_val->ptr - val->ptr) - 1;
       }
     }
   }
 
   return list;
 }
 
 // Perform case-insensitive match of string against pattern
 static int match_prefix(const char *pattern, int pattern_len, const char *str) {
   const char *or_str;
   int i, j, len, res;
 
   if ((or_str = (const char *) memchr(pattern, '|', pattern_len)) != NULL) {
     res = match_prefix(pattern, or_str - pattern, str);
     return res > 0 ? res :
         match_prefix(or_str + 1, (pattern + pattern_len) - (or_str + 1), str);
   }
 
   i = j = 0;
   res = -1;
   for (; i < pattern_len; i++, j++) {
     if (pattern[i] == '?' && str[j] != '\0') {
       continue;
     } else if (pattern[i] == '$') {
       return str[j] == '\0' ? j : -1;
     } else if (pattern[i] == '*') {
       i++;
       if (pattern[i] == '*') {
         i++;
         len = (int) strlen(str + j);
       } else {
         len = (int) strcspn(str + j, "/");
       }
       if (i == pattern_len) {
         return j + len;
       }
       do {
         res = match_prefix(pattern + i, pattern_len - i, str + j + len);
       } while (res == -1 && len-- > 0);
       return res == -1 ? -1 : j + res + len;
     } else if (lowercase(&pattern[i]) != lowercase(&str[j])) {
       return -1;
     }
   }
   return j;
 }
 
 // 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 = conn->request_info.http_version;
   const char *header = mg_get_header(conn, "Connection");
   if (conn->must_close ||
       conn->status_code == 401 ||
       mg_strcasecmp(conn->ctx->config[ENABLE_KEEP_ALIVE], "yes") != 0 ||
       (header != NULL && mg_strcasecmp(header, "keep-alive") != 0) ||
       (header == NULL && http_version && strcmp(http_version, "1.1"))) {
     return 0;
   }
   return 1;
 }
 
 static const char *suggest_connection_header(const struct mg_connection *conn) {
   return should_keep_alive(conn) ? "keep-alive" : "close";
 }
 
 static void send_http_error(struct mg_connection *, int, const char *,
                             PRINTF_FORMAT_STRING(const char *fmt), ...)
   PRINTF_ARGS(4, 5);
 
 
 static void send_http_error(struct mg_connection *conn, int status,
                             const char *reason, const char *fmt, ...) {
   char buf[MG_BUF_LEN];
   va_list ap;
   int len = 0;
 
   conn->status_code = status;
   if (conn->ctx->callbacks.http_error == NULL ||
       conn->ctx->callbacks.http_error(conn, status)) {
     buf[0] = '\0';
 
     // Errors 1xx, 204 and 304 MUST NOT send a body
     if (status > 199 && status != 204 && status != 304) {
       len = mg_snprintf(conn, buf, sizeof(buf), "Error %d: %s", status, reason);
       buf[len++] = '\n';
 
       va_start(ap, fmt);
       len += mg_vsnprintf(conn, buf + len, sizeof(buf) - len, fmt, ap);
       va_end(ap);
     }
     DEBUG_TRACE(("[%s]", buf));
 
     mg_printf(conn, "HTTP/1.1 %d %s\r\n"
               "Content-Length: %d\r\n"
               "Connection: %s\r\n\r\n", status, reason, len,
               suggest_connection_header(conn));
     conn->num_bytes_sent += mg_printf(conn, "%s", buf);
   }
 }
 
 #if defined(_WIN32) && !defined(__SYMBIAN32__)
 static int pthread_mutex_init(pthread_mutex_t *mutex, void *unused) {
   (void) unused;
   *mutex = CreateMutex(NULL, FALSE, NULL);
   return *mutex == NULL ? -1 : 0;
 }
 
 static int pthread_mutex_destroy(pthread_mutex_t *mutex) {
   return CloseHandle(*mutex) == 0 ? -1 : 0;
 }
 
 static int pthread_mutex_lock(pthread_mutex_t *mutex) {
   return WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0? 0 : -1;
 }
 
 static int pthread_mutex_unlock(pthread_mutex_t *mutex) {
   return ReleaseMutex(*mutex) == 0 ? -1 : 0;
 }
 
 static int pthread_cond_init(pthread_cond_t *cv, const void *unused) {
   (void) unused;
   cv->signal = CreateEvent(NULL, FALSE, FALSE, NULL);
   cv->broadcast = CreateEvent(NULL, TRUE, FALSE, NULL);
   return cv->signal != NULL && cv->broadcast != NULL ? 0 : -1;
 }
 
 static int pthread_cond_wait(pthread_cond_t *cv, pthread_mutex_t *mutex) {
   HANDLE handles[] = {cv->signal, cv->broadcast};
   ReleaseMutex(*mutex);
   WaitForMultipleObjects(2, handles, FALSE, INFINITE);
   return WaitForSingleObject(*mutex, INFINITE) == WAIT_OBJECT_0? 0 : -1;
 }
 
 static int pthread_cond_signal(pthread_cond_t *cv) {
   return SetEvent(cv->signal) == 0 ? -1 : 0;
 }
 
 static int pthread_cond_broadcast(pthread_cond_t *cv) {
   // Implementation with PulseEvent() has race condition, see
   // http://www.cs.wustl.edu/~schmidt/win32-cv-1.html
   return PulseEvent(cv->broadcast) == 0 ? -1 : 0;
 }
 
 static int pthread_cond_destroy(pthread_cond_t *cv) {
   return CloseHandle(cv->signal) && CloseHandle(cv->broadcast) ? 0 : -1;
 }
 
 // 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] = '\\';
     // i > 0 check is to preserve UNC paths, like \\server\file.txt
     if (path[i] == '\\' && i > 0)
       while (path[i + 1] == '\\' || path[i + 1] == '/')
         (void) memmove(path + i + 1,
             path + i + 2, strlen(path + i + 1));
   }
 }
 
 // Encode 'path' which is assumed UTF-8 string, into UNICODE string.
 // wbuf and wbuf_len is a target buffer and its length.
 static void to_unicode(const char *path, wchar_t *wbuf, size_t wbuf_len) {
   char buf[PATH_MAX], buf2[PATH_MAX];
 
   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';
   }
 }
 
 #if defined(_WIN32_WCE)
 static time_t time(time_t *ptime) {
   time_t t;
   SYSTEMTIME st;
   FILETIME ft;
 
   GetSystemTime(&st);
   SystemTimeToFileTime(&st, &ft);
   t = SYS2UNIX_TIME(ft.dwLowDateTime, ft.dwHighDateTime);
 
   if (ptime != NULL) {
     *ptime = t;
   }
 
   return t;
 }
 
 static struct tm *localtime(const time_t *ptime, struct tm *ptm) {
   int64_t t = ((int64_t) *ptime) * RATE_DIFF + EPOCH_DIFF;
   FILETIME ft, lft;
   SYSTEMTIME st;
   TIME_ZONE_INFORMATION tzinfo;
 
   if (ptm == NULL) {
     return NULL;
   }
 
   * (int64_t *) &ft = t;
   FileTimeToLocalFileTime(&ft, &lft);
   FileTimeToSystemTime(&lft, &st);
   ptm->tm_year = st.wYear - 1900;
   ptm->tm_mon = st.wMonth - 1;
   ptm->tm_wday = st.wDayOfWeek;
   ptm->tm_mday = st.wDay;
   ptm->tm_hour = st.wHour;
   ptm->tm_min = st.wMinute;
   ptm->tm_sec = st.wSecond;
   ptm->tm_yday = 0; // hope nobody uses this
   ptm->tm_isdst =
     GetTimeZoneInformation(&tzinfo) == TIME_ZONE_ID_DAYLIGHT ? 1 : 0;
 
   return ptm;
 }
 
 static struct tm *gmtime(const time_t *ptime, struct tm *ptm) {
   // FIXME(lsm): fix this.
   return localtime(ptime, ptm);
 }
 
 static size_t strftime(char *dst, size_t dst_size, const char *fmt,
                        const struct tm *tm) {
   (void) snprintf(dst, dst_size, "implement strftime() for WinCE");
   return 0;
 }
 #endif
 
 // 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.
 // This function returns non-0 if path ends with some garbage.
 static int path_cannot_disclose_cgi(const char *path) {
   static const char *allowed_last_characters = "_-";
   int last = path[strlen(path) - 1];
   return isalnum(last) || strchr(allowed_last_characters, last) != NULL;
 }
 
 static int mg_stat(struct mg_connection *conn, const char *path,
                    struct file *filep) {
   wchar_t wbuf[PATH_MAX];
   WIN32_FILE_ATTRIBUTE_DATA info;
 
   if (!is_file_in_memory(conn, path, filep)) {
     to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
     if (GetFileAttributesExW(wbuf, GetFileExInfoStandard, &info) != 0) {
       filep->size = MAKEUQUAD(info.nFileSizeLow, info.nFileSizeHigh);
       filep->modification_time = SYS2UNIX_TIME(
           info.ftLastWriteTime.dwLowDateTime,
           info.ftLastWriteTime.dwHighDateTime);
       filep->is_directory = info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
       // If file name is fishy, reset the file structure and return error.
       // Note it is important to reset, not just return the error, cause
       // functions like is_file_opened() check the struct.
       if (!filep->is_directory && !path_cannot_disclose_cgi(path)) {
         memset(filep, 0, sizeof(*filep));
       }
     }
   }
 
   return filep->membuf != NULL || filep->modification_time != 0;
 }
 
 static int mg_remove(const char *path) {
   wchar_t wbuf[PATH_MAX];
   to_unicode(path, wbuf, ARRAY_SIZE(wbuf));
   return DeleteFileW(wbuf) ? 0 : -1;
 }
 
 static int mg_mkdir(const char *path, int mode) {
   char buf[PATH_MAX];
   wchar_t wbuf[PATH_MAX];
 
   (void) mode;
   mg_strlcpy(buf, path, sizeof(buf));
   change_slashes_to_backslashes(buf);
 
   (void) MultiByteToWideChar(CP_UTF8, 0, buf, -1, wbuf, ARRAY_SIZE(wbuf));
 
   return CreateDirectoryW(wbuf, NULL) ? 0 : -1;
 }
 
 // Implementation of POSIX opendir/closedir/readdir for Windows.
 static DIR * opendir(const char *name) {
   DIR *dir = NULL;
   wchar_t wpath[PATH_MAX];
   DWORD attrs;
 
   if (name == NULL) {
     SetLastError(ERROR_BAD_ARGUMENTS);
   } else if ((dir = (DIR *) malloc(sizeof(*dir))) == NULL) {
     SetLastError(ERROR_NOT_ENOUGH_MEMORY);
   } else {
     to_unicode(name, wpath, ARRAY_SIZE(wpath));
     attrs = GetFileAttributesW(wpath);
     if (attrs != 0xFFFFFFFF &&
         ((attrs & FILE_ATTRIBUTE_DIRECTORY) == FILE_ATTRIBUTE_DIRECTORY)) {
       (void) wcscat(wpath, L"\\*");
       dir->handle = FindFirstFileW(wpath, &dir->info);
       dir->result.d_name[0] = '\0';
     } else {
       free(dir);
       dir = NULL;
     }
   }
 
   return dir;
 }
 
 static int closedir(DIR *dir) {
   int result = 0;
 
   if (dir != NULL) {
     if (dir->handle != INVALID_HANDLE_VALUE)
       result = FindClose(dir->handle) ? 0 : -1;
 
     free(dir);
   } else {
     result = -1;
     SetLastError(ERROR_BAD_ARGUMENTS);
   }
 
   return result;
 }
 
 static struct dirent *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;
 }
 
 static void set_close_on_exec(SOCKET sock) {
   (void) SetHandleInformation((HANDLE) sock, HANDLE_FLAG_INHERIT, 0);
 }
 
 int mg_start_thread(mg_thread_func_t f, void *p) {
   return (long)_beginthread((void (__cdecl *)(void *)) f, 0, p) == -1L ? -1 : 0;
 }
 
 static HANDLE dlopen(const char *dll_name, int flags) {
   wchar_t wbuf[PATH_MAX];
   (void) flags;
   to_unicode(dll_name, wbuf, ARRAY_SIZE(wbuf));
   return LoadLibraryW(wbuf);
 }
 
 #if !defined(NO_CGI)
 #define SIGKILL 0
 static int kill(pid_t pid, int sig_num) {
   (void) TerminateProcess(pid, sig_num);
   (void) CloseHandle(pid);
   return 0;
 }
 
 static void trim_trailing_whitespaces(char *s) {
   char *e = s + strlen(s) - 1;
   while (e > s && isspace(* (unsigned char *) e)) {
     *e-- = '\0';
   }
 }
 
 static pid_t spawn_process(struct mg_connection *conn, const char *prog,
                            char *envblk, char *envp[], int fdin,
                            int fdout, const char *dir) {
   HANDLE me;
   char *p, *interp, full_interp[PATH_MAX], full_dir[PATH_MAX],
        cmdline[PATH_MAX], buf[PATH_MAX];
   struct file file = STRUCT_FILE_INITIALIZER;
   STARTUPINFOA si;
   PROCESS_INFORMATION pi = { 0 };
 
   (void) envp;
 
   memset(&si, 0, sizeof(si));
   si.cb = sizeof(si);
 
   // TODO(lsm): redirect CGI errors to the error log file
   si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
   si.wShowWindow = SW_HIDE;
 
   me = GetCurrentProcess();
   DuplicateHandle(me, (HANDLE) _get_osfhandle(fdin), me,
                   &si.hStdInput, 0, TRUE, DUPLICATE_SAME_ACCESS);
   DuplicateHandle(me, (HANDLE) _get_osfhandle(fdout), me,
                   &si.hStdOutput, 0, TRUE, DUPLICATE_SAME_ACCESS);
 
   // If CGI file is a script, try to read the interpreter line
   interp = conn->ctx->config[CGI_INTERPRETER];
   if (interp == NULL) {
     buf[0] = buf[1] = '\0';
 
     // Read the first line of the script into the buffer
     snprintf(cmdline, sizeof(cmdline), "%s%c%s", dir, '/', prog);
     if (mg_fopen(conn, cmdline, "r", &file)) {
       p = (char *) file.membuf;
       mg_fgets(buf, sizeof(buf), &file, &p);
       mg_fclose(&file);
       buf[sizeof(buf) - 1] = '\0';
     }
 
     if (buf[0] == '#' && buf[1] == '!') {
       trim_trailing_whitespaces(buf + 2);
     } else {
       buf[2] = '\0';
     }
     interp = buf + 2;
   }
 
   if (interp[0] != '\0') {
     GetFullPathNameA(interp, sizeof(full_interp), full_interp, NULL);
     interp = full_interp;
   }
   GetFullPathNameA(dir, sizeof(full_dir), full_dir, NULL);
 
   mg_snprintf(conn, cmdline, sizeof(cmdline), "%s%s\"%s\\%s\"",
               interp, interp[0] == '\0' ? "" : " ", full_dir, prog);
 
   DEBUG_TRACE(("Running [%s]", cmdline));
   if (CreateProcessA(NULL, cmdline, NULL, NULL, TRUE,
         CREATE_NEW_PROCESS_GROUP, envblk, NULL, &si, &pi) == 0) {
     cry(conn, "%s: CreateProcess(%s): %ld",
         __func__, cmdline, ERRNO);
     pi.hProcess = (pid_t) -1;
   }
 
   (void) CloseHandle(si.hStdOutput);
   (void) CloseHandle(si.hStdInput);
   (void) CloseHandle(pi.hThread);
 
   return (pid_t) pi.hProcess;
 }
 #endif // !NO_CGI
 
 static int set_non_blocking_mode(SOCKET sock) {
   unsigned long on = 1;
   return ioctlsocket(sock, FIONBIO, &on);
 }
 
 #else
 static int mg_stat(struct mg_connection *conn, const char *path,
                    struct file *filep) {
   struct stat st;
 
   if (!is_file_in_memory(conn, path, filep) && !stat(path, &st)) {
     filep->size = st.st_size;
     filep->modification_time = st.st_mtime;
     filep->is_directory = S_ISDIR(st.st_mode);
   } else {
     filep->modification_time = (time_t) 0;
   }
 
   return filep->membuf != NULL || filep->modification_time != (time_t) 0;
 }
 
 static void set_close_on_exec(int fd) {
   fcntl(fd, F_SETFD, FD_CLOEXEC);
 }
 
 int mg_start_thread(mg_thread_func_t func, void *param) {
   pthread_t thread_id;
   pthread_attr_t attr;
   int result;
   struct mg_context* ctx = param;
   char* stacksize = ctx->config[THREAD_STACK_SIZE];
   char* priority = ctx->config[THREAD_PRIORITY];
   char* policy = ctx->config[THREAD_POLICY];
   int noinheritsched = 0;
 
   (void) pthread_attr_init(&attr);
   (void) pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 
 #if USE_STACK_SIZE > 1
   // Compile-time option to control stack size, e.g. -DUSE_STACK_SIZE=16384; Can be overridden
   if (stacksize == NULL)
     (void) pthread_attr_setstacksize(&attr, USE_STACK_SIZE);
 #endif
 
   if (stacksize != NULL) {
     size_t size = atoi(stacksize);
     (void) pthread_attr_setstacksize(&attr, size);
   }
 
   if (priority != NULL) {
     struct sched_param sched_param;
     memset(&sched_param, 0, sizeof(sched_param));
     sched_param.sched_priority = atoi(priority);
     (void) pthread_attr_setschedparam(&attr, &sched_param);
     noinheritsched = 1;
   }
 
   if (policy != NULL) {
     int p_policy;
     (void) pthread_attr_getschedpolicy(&attr, &p_policy);
 
     switch (policy[0]) {
       case 'o':
         p_policy = SCHED_OTHER;
         break;
       case 'f':
         p_policy = SCHED_FIFO;
         break;
       case 'r':
         p_policy = SCHED_RR;
         break;
 #if defined(_POSIX_SPORADIC_SERVER) || defined(_POSIX_THREAD_SPORADIC_SERVER)
       case 's':
         p_policy = SCHED_SPORADIC;
         break;
 #endif
       default:
         cry(fc(ctx), "%s: Unknown scheduler: %s", __func__, policy);
         break;
     }
 
     (void) pthread_attr_setschedpolicy(&attr, p_policy);
 
     noinheritsched = 1;
   }
 
   if (noinheritsched != 0) {
     (void) pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
   }
 
   result = pthread_create(&thread_id, &attr, func, param);
   pthread_attr_destroy(&attr);
 
   return result;
 }
 
 #ifndef NO_CGI
 static pid_t spawn_process(struct mg_connection *conn, const char *prog,
                            char *envblk, char *envp[], int fdin,
                            int fdout, const char *dir) {
   pid_t pid;
   const char *interp;
 
   (void) envblk;
 
   if ((pid = fork()) == -1) {
     // Parent
     send_http_error(conn, 500, http_500_error, "fork(): %s", strerror(ERRNO));
   } else if (pid == 0) {
     // Child
     if (chdir(dir) != 0) {
       cry(conn, "%s: chdir(%s): %s", __func__, dir, strerror(ERRNO));
     } else if (dup2(fdin, 0) == -1) {
       cry(conn, "%s: dup2(%d, 0): %s", __func__, fdin, strerror(ERRNO));
     } else if (dup2(fdout, 1) == -1) {
       cry(conn, "%s: dup2(%d, 1): %s", __func__, fdout, strerror(ERRNO));
     } else {
       // Not redirecting stderr to stdout, to avoid output being littered
       // with the error messages.
       (void) close(fdin);
       (void) close(fdout);
 
       // 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.
       signal(SIGCHLD, SIG_DFL);
 
       interp = conn->ctx->config[CGI_INTERPRETER];
       if (interp == NULL) {
         (void) execle(prog, prog, NULL, envp);
         cry(conn, "%s: execle(%s): %s", __func__, prog, strerror(ERRNO));
       } else {
         (void) execle(interp, interp, prog, NULL, envp);
         cry(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;
 
   flags = fcntl(sock, F_GETFL, 0);
   (void) fcntl(sock, F_SETFL, flags | O_NONBLOCK);
 
   return 0;
 }
 #endif // _WIN32
 
 #ifndef HAVE_POLL
 static int poll(struct pollfd *pfd, int n, int milliseconds) {
   struct timeval tv;
 #if __rtems__
   #define set (*set_prealloc)
   static fd_set *set_prealloc;
   static size_t set_size;
 #else
   fd_set set;
 #endif
   int i, result;
   SOCKET maxfd = 0;
 
   tv.tv_sec = milliseconds / 1000;
   tv.tv_usec = (milliseconds % 1000) * 1000;
 #if __rtems__
   if (set_prealloc == NULL) {
     set_size =
       sizeof(fd_set) * (howmany(rtems_libio_number_iops, sizeof(fd_set) * 8));
     set_prealloc = malloc(set_size);
     if (set_prealloc == NULL) {
       errno = ENOMEM;
       return -1;
     }
   }
   memset(set_prealloc, 0, set_size);
 #else
   FD_ZERO(&set);
 #endif
 
   for (i = 0; i < n; i++) {
     FD_SET((SOCKET) pfd[i].fd, &set);
     pfd[i].revents = 0;
 
     if (pfd[i].fd > maxfd) {
         maxfd = pfd[i].fd;
     }
   }
 
   if ((result = select(maxfd + 1, &set, NULL, NULL, &tv)) > 0) {
     for (i = 0; i < n; i++) {
       if (FD_ISSET(pfd[i].fd, &set)) {
         pfd[i].revents = POLLIN;
       }
     }
   }
 
   return result;
 }
 #endif // HAVE_POLL
 
 // Write data to the IO channel - opened file descriptor, socket or SSL
 // descriptor. Return number of bytes written.
 static int64_t push(FILE *fp, SOCKET sock, SSL *ssl, const char *buf,
                     int64_t len) {
   int64_t sent;
   int n, k;
 
   (void) ssl;  // Get rid of warning
   sent = 0;
   while (sent < len) {
 
     // How many bytes we send in this iteration
     k = len - sent > INT_MAX ? INT_MAX : (int) (len - sent);
 
 #ifndef NO_SSL
     if (ssl != NULL) {
       n = SSL_write(ssl, buf + sent, k);
     } else
 #endif
       if (fp != NULL) {
       n = (int) fwrite(buf + sent, 1, (size_t) k, fp);
       if (ferror(fp))
         n = -1;
     } else {
       n = send(sock, buf + sent, (size_t) k, MSG_NOSIGNAL);
     }
 
     if (n <= 0)
       break;
 
     sent += n;
   }
 
   return sent;
 }
 
 // Read from IO channel - opened file descriptor, socket, or SSL descriptor.
 // Return negative value on error, or number of bytes read on success.
 static int pull(FILE *fp, struct mg_connection *conn, char *buf, int len) {
   int nread;
 
   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 = read(fileno(fp), buf, (size_t) len);
 #ifndef NO_SSL
   } else if (conn->ssl != NULL) {
     nread = SSL_read(conn->ssl, buf, len);
 #endif
   } else {
     nread = recv(conn->client.sock, buf, (size_t) len, 0);
   }
 
   return conn->ctx->stop_flag ? -1 : nread;
 }
 
 static int pull_all(FILE *fp, struct mg_connection *conn, char *buf, int len) {
   int n, nread = 0;
 
   while (len > 0 && conn->ctx->stop_flag == 0) {
     n = pull(fp, conn, buf + nread, len);
     if (n < 0) {
       nread = n;  // Propagate the error
       break;
     } else if (n == 0) {
       break;  // No more data to read
     } else {
       conn->consumed_content += n;
       nread += n;
       len -= n;
     }
   }
 
   return nread;
 }
 
 int mg_read(struct mg_connection *conn, void *buf, size_t len) {
   int n, buffered_len, nread;
   const char *body;
 
   // If Content-Length is not set, read until socket is closed
   if (conn->consumed_content == 0 && conn->content_len == 0) {
     conn->content_len = INT64_MAX;
     conn->must_close = 1;
   }
 
   nread = 0;
   if (conn->consumed_content < conn->content_len) {
     // Adjust number of bytes to read.
     int64_t to_read = conn->content_len - conn->consumed_content;
     if (to_read < (int64_t) len) {
       len = (size_t) to_read;
     }
 
     // Return buffered data
     body = conn->buf + conn->request_len + conn->consumed_content;
     buffered_len = &conn->buf[conn->data_len] - body;
     if (buffered_len > 0) {
       if (len < (size_t) buffered_len) {
         buffered_len = (int) len;
       }
       memcpy(buf, body, (size_t) buffered_len);
       len -= 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.
     n = pull_all(NULL, conn, (char *) buf, (int) len);
     nread = n >= 0 ? nread + n : n;
   }
   return nread;
 }
 
 int mg_write(struct mg_connection *conn, const void *buf, size_t len) {
   time_t now;
   int64_t n, total, allowed;
 
   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 > (int64_t) len) {
       allowed = len;
     }
     if ((total = push(NULL, conn->client.sock, conn->ssl, (const char *) buf,
                       (int64_t) allowed)) == allowed) {
       buf = (char *) buf + total;
       conn->last_throttle_bytes += total;
       while (total < (int64_t) len && conn->ctx->stop_flag == 0) {
         allowed = conn->throttle > (int64_t) len - total ?
           (int64_t) len - total : conn->throttle;
         if ((n = push(NULL, conn->client.sock, conn->ssl, (const char *) buf,
                       (int64_t) allowed)) != allowed) {
           break;
         }
         sleep(1);
         conn->last_throttle_bytes = allowed;
         conn->last_throttle_time = time(NULL);
         buf = (char *) buf + n;
         total += n;
       }
     }
   } else {
     total = push(NULL, conn->client.sock, conn->ssl, (const char *) buf,
                  (int64_t) len);
   }
   return (int) total;
 }
 
 // Alternative alloc_vprintf() for non-compliant C runtimes
 static int alloc_vprintf2(char **buf, const char *fmt, va_list ap) {
   va_list ap_copy;
   int size = MG_BUF_LEN;
   int len = -1;
 
   *buf = NULL;
   while (len == -1) {
     if (*buf) free(*buf);
     *buf = malloc(size *= 4);
     if (!*buf) break;
     va_copy(ap_copy, ap);
     len = vsnprintf(*buf, size, fmt, ap_copy);
   }
 
   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 **buf, size_t 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(NULL, 0, fmt, 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(buf, fmt, ap);
   } else if (len > (int) size &&
       (size = len + 1) > 0 &&
       (*buf = (char *) malloc(size)) == NULL) {
     len = -1;  // Allocation failed, mark failure
   } else {
     va_copy(ap_copy, ap);
     vsnprintf(*buf, size, fmt, ap_copy);
   }
 
   return len;
 }
 
 static int mg_vprintf(struct mg_connection *conn, const char *fmt, va_list ap) {
   char mem[MG_BUF_LEN], *buf = mem;
   int len;
 
   if ((len = alloc_vprintf(&buf, sizeof(mem), fmt, ap)) > 0) {
     len = mg_write(conn, buf, (size_t) len);
   }
   if (buf != mem && buf != NULL) {
     free(buf);
   }
 
   return len;
 }
 
 int mg_printf(struct mg_connection *conn, const char *fmt, ...) {
   va_list ap;
   va_start(ap, fmt);
   return mg_vprintf(conn, fmt, ap);
 }
 
 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 (src[i] == '%' && i < src_len - 2 &&
         isxdigit(* (const unsigned char *) (src + i + 1)) &&
         isxdigit(* (const unsigned char *) (src + i + 2))) {
       a = tolower(* (const unsigned char *) (src + i + 1));
       b = tolower(* (const 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;
 }
 
 int mg_get_var(const char *data, size_t data_len, const char *name,
                char *dst, size_t dst_len) {
   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)) {
 
         // 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;
         }
         assert(s >= p);
 
         // Decode variable into destination buffer
         len = mg_url_decode(p, (size_t)(s - p), dst, dst_len, 1);
 
         // Redirect error code from -1 to -2 (destination buffer too small).
         if (len == -1) {
           len = -2;
         }
         break;
       }
     }
   }
 
   return len;
 }
 
 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) {
     len = -2;
   } else if (var_name == NULL || (s = cookie_header) == NULL) {
     len = -1;
     dst[0] = '\0';
   } else {
     name_len = (int) strlen(var_name);
     end = s + strlen(s);
     dst[0] = '\0';
 
     for (; (s = mg_strcasestr(s, var_name)) != NULL; s += name_len) {
       if (s[name_len] == '=') {
         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 = p - s;
           mg_strlcpy(dst, s, (size_t) len + 1);
         } else {
           len = -3;
         }
         break;
       }
     }
   }
   return len;
 }
 
 static void convert_uri_to_file_name(struct mg_connection *conn, char *buf,
                                      size_t buf_len, struct file *filep) {
   struct vec a, b;
   const char *rewrite, *uri = conn->request_info.uri,
         *root = conn->ctx->config[DOCUMENT_ROOT];
   char *p;
   int match_len;
   char gz_path[PATH_MAX + 3];
   char const* accept_encoding;
 
   // Using buf_len - 1 because memmove() for PATH_INFO may shift part
   // of the path one byte on the right.
   // If document_root is NULL, leave the file empty.
   mg_snprintf(conn, buf, buf_len - 1, "%s%s",
               root == NULL ? "" : root,
               root == NULL ? "" : uri);
 
   rewrite = conn->ctx->config[REWRITE];
   while ((rewrite = next_option(rewrite, &a, &b)) != NULL) {
     if ((match_len = match_prefix(a.ptr, a.len, uri)) > 0) {
       mg_snprintf(conn, buf, buf_len - 1, "%.*s%s", (int) b.len, b.ptr,
                   uri + match_len);
       break;
     }
   }
 
   if (mg_stat(conn, buf, filep)) return;
 
   // 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 ((accept_encoding = mg_get_header(conn, "Accept-Encoding")) != NULL) {
     if (strstr(accept_encoding,"gzip") != NULL) {
       snprintf(gz_path, sizeof(gz_path), "%s.gz", buf);
       if (mg_stat(conn, gz_path, filep)) {
         filep->gzipped = 1;
         return;
       }
     }
   }
 
   // Support PATH_INFO for CGI scripts.
   for (p = buf + strlen(buf); p > buf + 1; p--) {
     if (*p == '/') {
       *p = '\0';
       if (match_prefix(conn->ctx->config[CGI_EXTENSIONS],
                        strlen(conn->ctx->config[CGI_EXTENSIONS]), buf) > 0 &&
           mg_stat(conn, buf, filep)) {
         // Shift PATH_INFO block one character right, e.g.
         //  "/x.cgi/foo/bar\x00" => "/x.cgi\x00/foo/bar\x00"
         // conn->path_info is pointing to the local variable "path" declared
         // in handle_request(), so PATH_INFO is not valid after
         // handle_request returns.
         conn->path_info = p + 1;
         memmove(p + 2, p + 1, strlen(p + 1) + 1);  // +1 is for trailing \0
         p[1] = '/';
         break;
       } else {
         *p = '/';
       }
     }
   }
 }
 
 // Check whether full request is buffered. Return:
 //   -1  if request is malformed
 //    0  if request is not yet fully buffered
 //   >0  actual request length, including last \r\n\r\n
 static int get_request_len(const char *buf, int buflen) {
   const char *s, *e;
   int len = 0;
 
   for (s = buf, e = s + buflen - 1; len <= 0 && s < e; s++)
     // Control characters are not allowed but >=128 is.
     if (!isprint(* (const unsigned char *) s) && *s != '\r' &&
         *s != '\n' && * (const unsigned char *) s < 128) {
       len = -1;
       break;  // [i_a] abort scan as soon as one malformed character is found;
               // don't let subsequent \r\n\r\n win us over anyhow
     } else if (s[0] == '\n' && s[1] == '\n') {
       len = (int) (s - buf) + 2;
     } else if (s[0] == '\n' && &s[1] < e &&
         s[1] == '\r' && s[2] == '\n') {
       len = (int) (s - buf) + 3;
     }
 
   return len;
 }
 
 // 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;
 }
 
 static int num_leap_years(int year) {
   return year / 4 - year / 100 + year / 400;
 }
 
 // Parse UTC date-time string, and return the corresponding time_t value.
 static time_t parse_date_string(const char *datetime) {
   static const unsigned short days_before_month[] = {
     0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
   };
   char month_str[32];
   int second, minute, hour, day, month, year, leap_days, days;
   time_t result = (time_t) 0;
 
   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)) &&
       year > 1970 &&
       (month = get_month_index(month_str)) != -1) {
     leap_days = num_leap_years(year) - num_leap_years(1970);
     year -= 1970;
     days = year * 365 + days_before_month[month] + (day - 1) + leap_days;
     result = days * 24 * 3600 + hour * 3600 + minute * 60 + second;
   }
 
   return result;
 }
 
 // Protect against directory disclosure attack by removing '..',
 // excessive '/' and '\' characters
 static void remove_double_dots_and_double_slashes(char *s) {
   char *p = s;
 
   while (*s != '\0') {
     *p++ = *s++;
     if (s[-1] == '/' || s[-1] == '\\') {
       // Skip all following slashes, backslashes and double-dots
       while (s[0] != '\0') {
         if (s[0] == '/' || s[0] == '\\') {
           s++;
         } else if (s[0] == '.' && s[1] == '.') {
           s += 2;
         } else {
           break;
         }
       }
     }
   }
   *p = '\0';
 }
 
 static const struct {
   const char *extension;
   size_t ext_len;
   const char *mime_type;
 } builtin_mime_types[] = {
   {".html", 5, "text/html"},
   {".htm", 4, "text/html"},
   {".shtm", 5, "text/html"},
   {".shtml", 6, "text/html"},
   {".css", 4, "text/css"},
   {".js",  3, "application/x-javascript"},
   {".ico", 4, "image/x-icon"},
   {".gif", 4, "image/gif"},
   {".jpg", 4, "image/jpeg"},
   {".jpeg", 5, "image/jpeg"},
   {".png", 4, "image/png"},
   {".svg", 4, "image/svg+xml"},
   {".txt", 4, "text/plain"},
   {".torrent", 8, "application/x-bittorrent"},
   {".wav", 4, "audio/x-wav"},
   {".mp3", 4, "audio/x-mp3"},
   {".mid", 4, "audio/mid"},
   {".m3u", 4, "audio/x-mpegurl"},
   {".ogg", 4, "audio/ogg"},
   {".ram", 4, "audio/x-pn-realaudio"},
   {".xml", 4, "text/xml"},
   {".json",  5, "text/json"},
   {".xslt", 5, "application/xml"},
   {".xsl", 4, "application/xml"},
   {".ra",  3, "audio/x-pn-realaudio"},
   {".doc", 4, "application/msword"},
   {".exe", 4, "application/octet-stream"},
   {".zip", 4, "application/x-zip-compressed"},
   {".xls", 4, "application/excel"},
   {".tgz", 4, "application/x-tar-gz"},
   {".tar", 4, "application/x-tar"},
   {".gz",  3, "application/x-gunzip"},
   {".arj", 4, "application/x-arj-compressed"},
   {".rar", 4, "application/x-arj-compressed"},
   {".rtf", 4, "application/rtf"},
   {".pdf", 4, "application/pdf"},
   {".swf", 4, "application/x-shockwave-flash"},
   {".mpg", 4, "video/mpeg"},
   {".webm", 5, "video/webm"},
   {".mpeg", 5, "video/mpeg"},
   {".mov", 4, "video/quicktime"},
   {".mp4", 4, "video/mp4"},
   {".m4v", 4, "video/x-m4v"},
   {".asf", 4, "video/x-ms-asf"},
   {".avi", 4, "video/x-msvideo"},
   {".bmp", 4, "image/bmp"},
   {".ttf", 4, "application/x-font-ttf"},
   {NULL,  0, NULL}
 };
 
 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_context *ctx, const char *path,
                           struct vec *vec) {
   struct vec ext_vec, mime_vec;
   const char *list, *ext;
   size_t path_len;
 
   path_len = strlen(path);
 
   // Scan user-defined mime types first, in case user wants to
   // override default mime types.
   list = 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);
 }
 
 static int is_big_endian(void) {
   static const int n = 1;
   return ((char *) &n)[0] == 0;
 }
 
 #ifndef HAVE_MD5
 typedef struct MD5Context {
   uint32_t buf[4];
   uint32_t bits[2];
   unsigned char in[64];
 } MD5_CTX;
 
 static void byteReverse(unsigned char *buf, unsigned longs) {
   uint32_t t;
 
   // Forrest: MD5 expect LITTLE_ENDIAN, swap if BIG_ENDIAN
   if (is_big_endian()) {
     do {
       t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
         ((unsigned) buf[1] << 8 | buf[0]);
       * (uint32_t *) buf = t;
       buf += 4;
     } while (--longs);
   }
 }
 
 #define F1(x, y, z) (z ^ (x & (y ^ z)))
 #define F2(x, y, z) F1(z, x, y)
 #define F3(x, y, z) (x ^ y ^ z)
 #define F4(x, y, z) (y ^ (x | ~z))
 
 #define MD5STEP(f, w, x, y, z, data, s) \
   ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
 
 // Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 // initialization constants.
 static void MD5Init(MD5_CTX *ctx) {
   ctx->buf[0] = 0x67452301;
   ctx->buf[1] = 0xefcdab89;
   ctx->buf[2] = 0x98badcfe;
   ctx->buf[3] = 0x10325476;
 
   ctx->bits[0] = 0;
   ctx->bits[1] = 0;
 }
 
 static void MD5Transform(uint32_t buf[4], uint32_t const in[16]) {
   register uint32_t a, b, c, d;
 
   a = buf[0];
   b = buf[1];
   c = buf[2];
   d = buf[3];
 
   MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
   MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
   MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
   MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
   MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
   MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
   MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
   MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
   MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
   MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
   MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
   MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
   MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
   MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
   MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
   MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
 
   MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
   MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
   MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
   MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
   MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
   MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
   MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
   MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
   MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
   MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
   MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
   MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
   MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
   MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
   MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
   MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
 
   MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
   MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
   MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
   MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
   MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
   MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
   MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
   MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
   MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
   MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
   MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
   MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
   MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
   MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
   MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
   MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
 
   MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
   MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
   MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
   MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
   MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
   MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
   MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
   MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
   MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
   MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
   MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
   MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
   MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
   MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
   MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
   MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
 
   buf[0] += a;
   buf[1] += b;
   buf[2] += c;
   buf[3] += d;
 }
 
 static void MD5Update(MD5_CTX *ctx, unsigned char const *buf, unsigned len) {
   uint32_t t;
 
   t = ctx->bits[0];
   if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
     ctx->bits[1]++;
   ctx->bits[1] += len >> 29;
 
   t = (t >> 3) & 0x3f;
 
   if (t) {
     unsigned char *p = (unsigned char *) ctx->in + t;
 
     t = 64 - t;
     if (len < t) {
       memcpy(p, buf, len);
       return;
     }
     memcpy(p, buf, t);
     byteReverse(ctx->in, 16);
     MD5Transform(ctx->buf, (uint32_t *) ctx->in);
     buf += t;
     len -= t;
   }
 
   while (len >= 64) {
     memcpy(ctx->in, buf, 64);
     byteReverse(ctx->in, 16);
     MD5Transform(ctx->buf, (uint32_t *) ctx->in);
     buf += 64;
     len -= 64;
   }
 
   memcpy(ctx->in, buf, len);
 }
 
 static void MD5Final(unsigned char digest[16], MD5_CTX *ctx) {
   unsigned count;
   unsigned char *p;
   uint32_t *a;
 
   count = (ctx->bits[0] >> 3) & 0x3F;
 
   p = ctx->in + count;
   *p++ = 0x80;
   count = 64 - 1 - count;
   if (count < 8) {
     memset(p, 0, count);
     byteReverse(ctx->in, 16);
     MD5Transform(ctx->buf, (uint32_t *) ctx->in);
     memset(ctx->in, 0, 56);
   } else {
     memset(p, 0, count - 8);
   }
   byteReverse(ctx->in, 14);
 
   a = (uint32_t *)ctx->in;
   a[14] = ctx->bits[0];
   a[15] = ctx->bits[1];
 
   MD5Transform(ctx->buf, (uint32_t *) ctx->in);
   byteReverse((unsigned char *) ctx->buf, 4);
   memcpy(digest, ctx->buf, 16);
   memset((char *) ctx, 0, sizeof(*ctx));
 }
 #endif // !HAVE_MD5
 
 // 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.
 char *mg_md5(char buf[33], ...) {
   unsigned char hash[16];
   const char *p;
   va_list ap;
   MD5_CTX ctx;
 
   MD5Init(&ctx);
 
   va_start(ap, buf);
   while ((p = va_arg(ap, const char *)) != NULL) {
     MD5Update(&ctx, (const unsigned char *) p, (unsigned) strlen(p));
   }
   va_end(ap);
 
   MD5Final(hash, &ctx);
   bin2str(buf, hash, sizeof(hash));
   return buf;
 }
 
 // Check the user's password, return 1 if OK
 static int check_password(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
   // TODO(lsm): check for authentication timeout
   if (// strcmp(dig->uri, c->ouri) != 0 ||
       strlen(response) != 32
       // || now - strtoul(dig->nonce, NULL, 10) > 3600
       ) {
     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;
 }
 
 // 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 file *filep) {
   char name[PATH_MAX];
   const char *p, *e, *gpass = conn->ctx->config[GLOBAL_PASSWORDS_FILE];
   struct file file = STRUCT_FILE_INITIALIZER;
 
   if (gpass != NULL) {
     // Use global passwords file
     if (!mg_fopen(conn, gpass, "r", filep)) {
       cry(conn, "fopen(%s): %s", gpass, strerror(ERRNO));
     }
     // Important: using local struct file to test path for is_directory flag.
     // If filep is used, mg_stat() makes it appear as if auth file was opened.
   } else if (mg_stat(conn, path, &file) && file.is_directory) {
     mg_snprintf(conn, name, sizeof(name), "%s%c%s",
                 path, '/', PASSWORDS_FILE_NAME);
     mg_fopen(conn, name, "r", filep);
   } 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, name, sizeof(name), "%.*s%c%s",
                 (int) (e - p), p, '/', PASSWORDS_FILE_NAME);
     mg_fopen(conn, name, "r", filep);
   }
 }
 
 // Parsed Authorization header
 struct ah {
   char *user, *uri, *cnonce, *response, *qop, *nc, *nonce;
 };
 
 // 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;
 
   (void) memset(ah, 0, sizeof(*ah));
   if ((auth_header = mg_get_header(conn, "Authorization")) == NULL ||
       mg_strncasecmp(auth_header, "Digest ", 7) != 0) {
     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;
     }
   }
 
   // CGI needs it as REMOTE_USER
   if (ah->user != NULL) {
     conn->request_info.remote_user = mg_strdup(ah->user);
   } else {
     return 0;
   }
 
   return 1;
 }
 
 static char *mg_fgets(char *buf, size_t size, struct file *filep, char **p) {
   char *eof;
   size_t len;
   char *memend;
 
   if (filep->membuf != NULL && *p != NULL) {
     memend = (char *) &filep->membuf[filep->size];
     eof = (char *) memchr(*p, '\n', memend - *p); // Search for \n from p till the end of stream
     if (eof != NULL) {
       eof += 1; // Include \n
     } else {
       eof = memend; // Copy remaining data
     }
     len = (size_t) (eof - *p) > size - 1 ? size - 1 : (size_t) (eof - *p);
     memcpy(buf, *p, len);
     buf[len] = '\0';
     *p += len;
     return len ? eof : NULL;
   } else if (filep->fp != NULL) {
     return fgets(buf, size, filep->fp);
   } else {
     return NULL;
   }
 }
 
 // Authorize against the opened passwords file. Return 1 if authorized.
 static int authorize(struct mg_connection *conn, struct file *filep) {
   struct ah ah;
   char line[256], f_user[256], ha1[256], f_domain[256], buf[MG_BUF_LEN], *p;
 
   if (!parse_auth_header(conn, buf, sizeof(buf), &ah)) {
     return 0;
   }
 
   // Loop over passwords file
   p = (char *) filep->membuf;
   while (mg_fgets(line, sizeof(line), filep, &p) != NULL) {
     if (sscanf(line, "%[^:]:%[^:]:%s", f_user, f_domain, ha1) != 3) {
       continue;
     }
 
     if (!strcmp(ah.user, f_user) &&
         !strcmp(conn->ctx->config[AUTHENTICATION_DOMAIN], f_domain))
       return check_password(conn->request_info.request_method, ha1, ah.uri,
                             ah.nonce, ah.nc, ah.cnonce, ah.qop, ah.response);
   }
 
   return 0;
 }
 
 // Return 1 if request is authorised, 0 otherwise.
 static int check_authorization(struct mg_connection *conn, const char *path) {
   char fname[PATH_MAX];
   struct vec uri_vec, filename_vec;
   const char *list;
   struct file file = STRUCT_FILE_INITIALIZER;
   int authorized = 1;
 
   list = conn->ctx->config[PROTECT_URI];
   while ((list = next_option(list, &uri_vec, &filename_vec)) != NULL) {
     if (!memcmp(conn->request_info.uri, uri_vec.ptr, uri_vec.len)) {
       mg_snprintf(conn, fname, sizeof(fname), "%.*s",
                   (int) filename_vec.len, filename_vec.ptr);
       if (!mg_fopen(conn, fname, "r", &file)) {
         cry(conn, "%s: cannot open %s: %s", __func__, fname, strerror(errno));
       }
       break;
     }
   }
 
   if (!is_file_opened(&file)) {
     open_auth_file(conn, path, &file);
   }
 
   if (is_file_opened(&file)) {
     authorized = authorize(conn, &file);
     mg_fclose(&file);
   }
 
   return authorized;
 }
 
 static void send_authorization_request(struct mg_connection *conn) {
   conn->status_code = 401;
   mg_printf(conn,
             "HTTP/1.1 401 Unauthorized\r\n"
             "Content-Length: 0\r\n"
             "WWW-Authenticate: Digest qop=\"auth\", "
             "realm=\"%s\", nonce=\"%lu\"\r\n\r\n",
             conn->ctx->config[AUTHENTICATION_DOMAIN],
             (unsigned long) time(NULL));
 }
 
 static int is_authorized_for_put(struct mg_connection *conn) {
   struct file file = STRUCT_FILE_INITIALIZER;
   const char *passfile = conn->ctx->config[PUT_DELETE_PASSWORDS_FILE];
   int ret = 0;
 
   if (passfile != NULL && mg_fopen(conn, passfile, "r", &file)) {
     ret = authorize(conn, &file);
     mg_fclose(&file);
   }
 
   return ret;
 }
 
 int mg_modify_passwords_file(const char *fname, const char *domain,
                              const char *user, const char *pass) {
   int found;
   char line[512], u[512], d[512], ha1[33], tmp[PATH_MAX];
   FILE *fp, *fp2;
 
   found = 0;
   fp = fp2 = NULL;
 
   // Regard empty password as no password - remove user record.
   if (pass != NULL && pass[0] == '\0') {
     pass = NULL;
   }
 
   (void) snprintf(tmp, sizeof(tmp), "%s.tmp", fname);
 
   // Create the file if does not exist
   if ((fp = fopen(fname, "a+")) != NULL) {
     (void) fclose(fp);
   }
 
   // Open the given file and temporary file
   if ((fp = fopen(fname, "r")) == NULL) {
     return 0;
   } else if ((fp2 = fopen(tmp, "w+")) == NULL) {
     fclose(fp);
     return 0;
   }
 
   // Copy the stuff to temporary file
   while (fgets(line, sizeof(line), fp) != NULL) {
     if (sscanf(line, "%[^:]:%[^:]:%*s", u, d) != 2) {
       continue;
     }
 
     if (!strcmp(u, user) && !strcmp(d, domain)) {
       found++;
       if (pass != NULL) {
         mg_md5(ha1, user, ":", domain, ":", pass, NULL);
         fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
       }
     } else {
       fprintf(fp2, "%s", line);
     }
   }
 
   // If new user, just add it
   if (!found && pass != NULL) {
     mg_md5(ha1, user, ":", domain, ":", pass, NULL);
     fprintf(fp2, "%s:%s:%s\n", user, domain, ha1);
   }
 
   // Close files
   fclose(fp);
   fclose(fp2);
 
   // Put the temp file in place of real file
   remove(fname);
   rename(tmp, fname);
 
   return 1;
 }
 
 static SOCKET conn2(const char *host, int port, int use_ssl,
                     char *ebuf, size_t ebuf_len) {
   struct sockaddr_in sin;
   struct hostent *he;
   SOCKET sock = INVALID_SOCKET;
 
   if (host == NULL) {
     snprintf(ebuf, ebuf_len, "%s", "NULL host");
   } else if (use_ssl && SSLv23_client_method == NULL) {
     snprintf(ebuf, ebuf_len, "%s", "SSL is not initialized");
     // TODO(lsm): use something threadsafe instead of gethostbyname()
   } else if ((he = gethostbyname(host)) == NULL) {
     snprintf(ebuf, ebuf_len, "gethostbyname(%s): %s", host, strerror(ERRNO));
   } else if ((sock = socket(PF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) {
     snprintf(ebuf, ebuf_len, "socket(): %s", strerror(ERRNO));
   } else {
     set_close_on_exec(sock);
     sin.sin_family = AF_INET;
     sin.sin_port = htons((uint16_t) port);
     sin.sin_addr = * (struct in_addr *) he->h_addr_list[0];
     if (connect(sock, (struct sockaddr *) &sin, sizeof(sin)) != 0) {
       snprintf(ebuf, ebuf_len, "connect(%s:%d): %s",
                host, port, strerror(ERRNO));
       closesocket(sock);
       sock = INVALID_SOCKET;
     }
   }
   return sock;
 }
 
 
 
 static void mg_url_encode(const char *src, char *dst, size_t dst_len) {
   static const char *dont_escape = "._-$,;~()";
   static const char *hex = "0123456789abcdef";
   const char *end = dst + dst_len - 1;
 
   for (; *src != '\0' && dst < end; src++, dst++) {
     if (isalnum(*(const unsigned char *) src) ||
         strchr(dont_escape, * (const unsigned char *) src) != NULL) {
       *dst = *src;
     } else if (dst + 2 < end) {
       dst[0] = '%';
       dst[1] = hex[(* (const unsigned char *) src) >> 4];
       dst[2] = hex[(* (const unsigned char *) src) & 0xf];
       dst += 2;
     }
   }
 
   *dst = '\0';
 }
 
 static void print_dir_entry(struct de *de) {
   char size[64], mod[64], href[PATH_MAX];
 
   if (de->file.is_directory) {
     mg_snprintf(de->conn, 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(de->conn, size, sizeof(size), "%d", (int) de->file.size);
     } else if (de->file.size < 0x100000) {
       mg_snprintf(de->conn, size, sizeof(size),
                   "%.1fk", (double) de->file.size / 1024.0);
     } else if (de->file.size < 0x40000000) {
       mg_snprintf(de->conn, size, sizeof(size),
                   "%.1fM", (double) de->file.size / 1048576);
     } else {
       mg_snprintf(de->conn, size, sizeof(size),
                   "%.1fG", (double) de->file.size / 1073741824);
     }
   }
   strftime(mod, sizeof(mod), "%d-%b-%Y %H:%M",
            localtime(&de->file.modification_time));
   mg_url_encode(de->file_name, href, sizeof(href));
   de->conn->num_bytes_sent += mg_printf(de->conn,
       "<tr><td><a href=\"%s%s%s\">%s%s</a></td>"
       "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
       de->conn->request_info.uri, href, de->file.is_directory ? "/" : "",
       de->file_name, de->file.is_directory ? "/" : "", mod, size);
 }
 
 // This function is called from send_directory() and used for
 // sorting directory entries by size, or name, or modification time.
 // On windows, __cdecl specification is needed in case if project is built
 // with __stdcall convention. qsort always requires __cdels callback.
 static int WINCDECL compare_dir_entries(const void *p1, const void *p2) {
   const struct de *a = (const struct de *) p1, *b = (const struct de *) p2;
   const char *query_string = a->conn->request_info.query_string;
   int cmp_result = 0;
 
   if (query_string == NULL) {
     query_string = "na";
   }
 
   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
   } else if (*query_string == 'n') {
     cmp_result = strcmp(a->file_name, b->file_name);
   } else 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.modification_time == b->file.modification_time ? 0 :
       a->file.modification_time > b->file.modification_time ? 1 : -1;
   }
 
   return query_string[1] == 'd' ? -cmp_result : cmp_result;
 }
 
 static int must_hide_file(struct mg_connection *conn, const char *path) {
   const char *pw_pattern = "**" PASSWORDS_FILE_NAME "$";
   const char *pattern = conn->ctx->config[HIDE_FILES];
   return match_prefix(pw_pattern, strlen(pw_pattern), path) > 0 ||
     (pattern != NULL && match_prefix(pattern, strlen(pattern), path) > 0);
 }
 
 static int scan_directory(struct mg_connection *conn, const char *dir,
                           void *data, void (*cb)(struct de *, void *)) {
   char path[PATH_MAX];
   struct dirent *dp;
   DIR *dirp;
   struct de de;
 
   if ((dirp = opendir(dir)) == NULL) {
     return 0;
   } else {
     de.conn = conn;
 
     while ((dp = 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, path, sizeof(path), "%s%c%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));
       mg_stat(conn, path, &de.file);
 
       de.file_name = dp->d_name;
       cb(&de, data);
     }
     (void) closedir(dirp);
   }
   return 1;
 }
 
 static int remove_directory(struct mg_connection *conn, const char *dir) {
   char path[PATH_MAX];
   struct dirent *dp;
   DIR *dirp;
   struct de de;
 
   if ((dirp = opendir(dir)) == NULL) {
     return 0;
   } else {
     de.conn = conn;
 
     while ((dp = 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, path, sizeof(path), "%s%c%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));
       mg_stat(conn, path, &de.file);
       if(de.file.modification_time) {
           if(de.file.is_directory) {
               remove_directory(conn, path);
           } else {
               mg_remove(path);
           }
       }
 
     }
     (void) closedir(dirp);
 
     rmdir(dir);
   }
 
   return 1;
 }
 
 struct dir_scan_data {
   struct de *entries;
   int num_entries;
   int arr_size;
 };
 
 // Behaves like realloc(), but frees original pointer on failure
 static void *realloc2(void *ptr, size_t size) {
   void *new_ptr = realloc(ptr, size);
   if (new_ptr == NULL) {
     free(ptr);
   }
   return new_ptr;
 }
 
 static void dir_scan_callback(struct de *de, void *data) {
   struct dir_scan_data *dsd = (struct dir_scan_data *) data;
 
   if (dsd->entries == NULL || dsd->num_entries >= dsd->arr_size) {
     dsd->arr_size *= 2;
     dsd->entries = (struct de *) realloc2(dsd->entries, dsd->arr_size *
                                           sizeof(dsd->entries[0]));
   }
   if (dsd->entries == NULL) {
     // TODO(lsm): propagate an error to the caller
     dsd->num_entries = 0;
   } else {
     dsd->entries[dsd->num_entries].file_name = mg_strdup(de->file_name);
     dsd->entries[dsd->num_entries].file = de->file;
     dsd->entries[dsd->num_entries].conn = de->conn;
     dsd->num_entries++;
   }
 }
 
 static void handle_directory_request(struct mg_connection *conn,
                                      const char *dir) {
   int i, sort_direction;
   struct dir_scan_data data = { NULL, 0, 128 };
 
   if (!scan_directory(conn, dir, &data, dir_scan_callback)) {
     send_http_error(conn, 500, "Cannot open directory",
                     "Error: opendir(%s): %s", dir, strerror(ERRNO));
     return;
   }
 
   sort_direction = conn->request_info.query_string != NULL &&
     conn->request_info.query_string[1] == 'd' ? 'a' : 'd';
 
   conn->must_close = 1;
   mg_printf(conn, "%s",
             "HTTP/1.1 200 OK\r\n"
             "Connection: close\r\n"
             "Content-Type: text/html; charset=utf-8\r\n\r\n");
 
   conn->num_bytes_sent += mg_printf(conn,
       "<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>",
       conn->request_info.uri, conn->request_info.uri,
       sort_direction, sort_direction, sort_direction);
 
   // Print first entry - link to a parent directory
   conn->num_bytes_sent += mg_printf(conn,
       "<tr><td><a href=\"%s%s\">%s</a></td>"
       "<td>&nbsp;%s</td><td>&nbsp;&nbsp;%s</td></tr>\n",
       conn->request_info.uri, "..", "Parent directory", "-", "-");
 
   // Sort and print directory entries
   qsort(data.entries, (size_t) data.num_entries, sizeof(data.entries[0]),
         compare_dir_entries);
   for (i = 0; i < data.num_entries; i++) {
     print_dir_entry(&data.entries[i]);
     free(data.entries[i].file_name);
   }
   free(data.entries);
 
   conn->num_bytes_sent += mg_printf(conn, "%s", "</table></body></html>");
   conn->status_code = 200;
 }
 
 // Send len bytes from the opened file to the client.
 static void send_file_data(struct mg_connection *conn, struct file *filep,
                            int64_t offset, int64_t len) {
   char buf[MG_BUF_LEN];
   int to_read, num_read, num_written;
 
   // Sanity check the offset
   offset = offset < 0 ? 0 : offset > filep->size ? filep->size : offset;
 
   if (len > 0 && filep->membuf != NULL && filep->size > 0) {
     if (len > filep->size - offset) {
       len = filep->size - offset;
     }
     mg_write(conn, filep->membuf + offset, (size_t) len);
   } else if (len > 0 && filep->fp != NULL) {
     fseeko(filep->fp, offset, SEEK_SET);
     while (len > 0) {
       // Calculate how much to read from the file in the buffer
       to_read = sizeof(buf);
       if ((int64_t) to_read > len) {
         to_read = (int) len;
       }
 
       // Read from file, exit the loop on error
       if ((num_read = fread(buf, 1, (size_t) to_read, filep->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
       conn->num_bytes_sent += num_written;
       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);
 }
 
 static void gmt_time_string(char *buf, size_t buf_len, time_t *t) {
   strftime(buf, buf_len, "%a, %d %b %Y %H:%M:%S GMT", gmtime(t));
 }
 
 static void construct_etag(const struct mg_connection *conn, const char *path,
                            char *buf, size_t buf_len,
                            const struct file *filep) {
   if (conn->ctx->callbacks.http_etag != NULL &&
       conn->ctx->callbacks.http_etag(conn, path, buf, buf_len)) {
   }
   else {
     snprintf(buf, buf_len, "\"%lx.%" INT64_FMT "\"",
              (unsigned long) filep->modification_time, filep->size);
   }
 }
 
 static void fclose_on_exec(struct file *filep) {
   if (filep != NULL && filep->fp != NULL) {
 #ifndef _WIN32
     fcntl(fileno(filep->fp), F_SETFD, FD_CLOEXEC);
 #endif
   }
 }
 
 static void handle_file_request(struct mg_connection *conn, const char *path,
                                 struct file *filep) {
   char date[64], lm[64], etag[64], range[64];
   const char *msg = "OK", *hdr;
   time_t curtime = time(NULL);
   int64_t cl, r1, r2;
   struct vec mime_vec;
   int n;
   char gz_path[PATH_MAX + 3];
   char const* encoding = "";
 
   get_mime_type(conn->ctx, path, &mime_vec);
   cl = filep->size;
   conn->status_code = 200;
   range[0] = '\0';
 
   // 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 (filep->gzipped) {
     snprintf(gz_path, sizeof(gz_path), "%s.gz", path);
     path = gz_path;
     encoding = "Content-Encoding: gzip\r\n";
   }
 
   if (!mg_fopen(conn, path, "rb", filep)) {
     send_http_error(conn, 500, http_500_error,
                     "fopen(%s): %s", path, strerror(ERRNO));
     return;
   }
 
   fclose_on_exec(filep);
 
   // If Range: header specified, act accordingly
   r1 = r2 = 0;
   hdr = mg_get_header(conn, "Range");
   if (hdr != NULL && (n = parse_range_header(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 uncmpressed space)
     if (filep->gzipped) {
       send_http_error(conn, 501, "Not Implemented", "range requests in gzipped files are not supported");
       return;
     }
     conn->status_code = 206;
     cl = n == 2 ? (r2 > cl ? cl : r2) - r1 + 1: cl - r1;
     mg_snprintf(conn, range, sizeof(range),
                 "Content-Range: bytes "
                 "%" INT64_FMT "-%"
                 INT64_FMT "/%" INT64_FMT "\r\n",
                 r1, r1 + cl - 1, filep->size);
     msg = "Partial Content";
   }
 
   // Prepare Etag, Date, Last-Modified headers. Must be in UTC, according to
   // http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.3
   gmt_time_string(date, sizeof(date), &curtime);
   gmt_time_string(lm, sizeof(lm), &filep->modification_time);
   construct_etag(conn, path, etag, sizeof(etag), filep);
 
   (void) mg_printf(conn,
       "HTTP/1.1 %d %s\r\n"
       "Date: %s\r\n"
       "Last-Modified: %s\r\n"
       "Etag: %s\r\n"
       "Content-Type: %.*s\r\n"
       "Content-Length: %" INT64_FMT "\r\n"
       "Connection: %s\r\n"
       "Accept-Ranges: bytes\r\n"
       "%s%s\r\n",
       conn->status_code, msg, date, lm, etag, (int) mime_vec.len,
       mime_vec.ptr, cl, suggest_connection_header(conn), range, encoding);
 
   if (strcmp(conn->request_info.request_method, "HEAD") != 0) {
     send_file_data(conn, filep, r1, cl);
   }
   mg_fclose(filep);
 }
 
 void mg_send_file(struct mg_connection *conn, const char *path) {
   struct file file = STRUCT_FILE_INITIALIZER;
   if (mg_stat(conn, path, &file)) {
     handle_file_request(conn, path, &file);
   } else {
     send_http_error(conn, 404, "Not Found", "%s", "File not found");
   }
 }
 
 
 // Parse HTTP headers from the given buffer, advance buffer to the point
 // where parsing stopped.
 static void parse_http_headers(char **buf, struct mg_request_info *ri) {
   int i;
 
   for (i = 0; i < (int) ARRAY_SIZE(ri->http_headers); i++) {
     ri->http_headers[i].name = skip_quoted(buf, ":", " ", 0);
     ri->http_headers[i].value = skip(buf, "\r\n");
     if (ri->http_headers[i].name[0] == '\0')
       break;
     ri->num_headers = i + 1;
   }
 }
 
 static int is_valid_http_method(const char *method) {
   return !strcmp(method, "GET") || !strcmp(method, "POST") ||
     !strcmp(method, "HEAD") || !strcmp(method, "CONNECT") ||
     !strcmp(method, "PUT") || !strcmp(method, "DELETE") ||
     !strcmp(method, "OPTIONS") || !strcmp(method, "PROPFIND")
     || !strcmp(method, "MKCOL")
           ;
 }
 
 // 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.
 static int parse_http_message(char *buf, int len, struct mg_request_info *ri) {
   int is_request, request_length = get_request_len(buf, len);
   if (request_length > 0) {
     // Reset attributes. DO NOT TOUCH is_ssl, remote_ip, remote_port
     ri->remote_user = ri->request_method = ri->uri = ri->http_version = NULL;
     ri->num_headers = 0;
 
     buf[request_length - 1] = '\0';
 
     // RFC says that all initial whitespaces should be ingored
     while (*buf != '\0' && isspace(* (unsigned char *) buf)) {
       buf++;
     }
     ri->request_method = skip(&buf, " ");
     ri->uri = skip(&buf, " ");
     ri->http_version = skip(&buf, "\r\n");
 
     // HTTP message could be either HTTP request or HTTP response, e.g.
     // "GET / HTTP/1.0 ...." or  "HTTP/1.0 200 OK ..."
     is_request = is_valid_http_method(ri->request_method);
     if ((is_request && memcmp(ri->http_version, "HTTP/", 5) != 0) ||
         (!is_request && memcmp(ri->request_method, "HTTP/", 5) != 0)) {
       request_length = -1;
     } else {
       if (is_request) {
         ri->http_version += 5;
       }
       parse_http_headers(&buf, ri);
     }
   }
   return request_length;
 }
 
 // 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_request(FILE *fp, struct mg_connection *conn,
                         char *buf, int bufsiz, int *nread) {
   int request_len, n = 0;
 
   request_len = get_request_len(buf, *nread);
   while (conn->ctx->stop_flag == 0 &&
          *nread < bufsiz && request_len == 0 &&
          (n = pull(fp, conn, buf + *nread, bufsiz - *nread)) > 0) {
     *nread += n;
     assert(*nread <= bufsiz);
     request_len = get_request_len(buf, *nread);
   }
 
   return request_len <= 0 && n <= 0 ? -1 : request_len;
 }
 
 // For given directory path, substitute it to valid index file.
 // Return 0 if index file has been found, -1 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 file *filep) {
   const char *list = conn->ctx->config[INDEX_FILES];
   struct file file = STRUCT_FILE_INITIALIZER;
   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 > path_len - (n + 2))
       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, &file)) {
       // Yes it does, break the loop
       *filep = file;
       found = 1;
       break;
     }
   }
 
   // If no index file exists, restore directory path
   if (!found) {
     path[n] = '\0';
   }
 
   return found;
 }
 
 // Return True if we should reply 304 Not Modified.
 static int is_not_modified(const struct mg_connection *conn,
                            const char *path,
                            const struct file *filep) {
   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(conn, path, etag, sizeof(etag), filep);
   return (inm != NULL && !mg_strcasecmp(etag, inm)) ||
     (ims != NULL && filep->modification_time <= parse_date_string(ims));
 }
 
 static int forward_body_data(struct mg_connection *conn, FILE *fp,
                              SOCKET sock, SSL *ssl) {
   const char *expect, *body;
   char buf[MG_BUF_LEN];
   int to_read, nread, buffered_len, success = 0;
 
   expect = mg_get_header(conn, "Expect");
   assert(fp != NULL);
 
   if (conn->content_len == -1) {
     send_http_error(conn, 411, "Length Required", "%s", "");
   } else if (expect != NULL && mg_strcasecmp(expect, "100-continue")) {
     send_http_error(conn, 417, "Expectation Failed", "%s", "");
   } else {
     if (expect != NULL) {
       (void) mg_printf(conn, "%s", "HTTP/1.1 100 Continue\r\n\r\n");
     }
 
     body = conn->buf + conn->request_len + conn->consumed_content;
     buffered_len = &conn->buf[conn->data_len] - body;
     assert(buffered_len >= 0);
     assert(conn->consumed_content == 0);
 
     if (buffered_len > 0) {
       if ((int64_t) buffered_len > conn->content_len) {
         buffered_len = (int) conn->content_len;
       }
       push(fp, sock, ssl, body, (int64_t) buffered_len);
       conn->consumed_content += buffered_len;
     }
 
     nread = 0;
     while (conn->consumed_content < conn->content_len) {
       to_read = sizeof(buf);
       if ((int64_t) to_read > conn->content_len - conn->consumed_content) {
         to_read = (int) (conn->content_len - conn->consumed_content);
       }
       nread = pull(NULL, conn, buf, to_read);
       if (nread <= 0 || push(fp, sock, ssl, buf, nread) != nread) {
         break;
       }
       conn->consumed_content += nread;
     }
 
     if (conn->consumed_content == conn->content_len) {
       success = nread >= 0;
     }
 
     // Each error code path in this function must send an error
     if (!success) {
       send_http_error(conn, 577, http_500_error, "%s", "");
     }
   }
 
   return success;
 }
 
 #if !defined(NO_CGI)
 // This structure helps to create an environment for the spawned CGI program.
 // Environment is an array of "VARIABLE=VALUE\0" ASCIIZ 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_env_block {
   struct mg_connection *conn;
   char buf[CGI_ENVIRONMENT_SIZE]; // Environment buffer
   int len; // Space taken
   char *vars[MAX_CGI_ENVIR_VARS]; // char **envp
   int nvars; // Number of variables
 };
 
 static char *addenv(struct cgi_env_block *block,
                     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.
 static char *addenv(struct cgi_env_block *block, const char *fmt, ...) {
   int n, space;
   char *added;
   va_list ap;
 
   // Calculate how much space is left in the buffer
   space = sizeof(block->buf) - block->len - 2;
   assert(space >= 0);
 
   // Make a pointer to the free space int the buffer
   added = block->buf + block->len;
 
   // Copy VARIABLE=VALUE\0 string into the free space
   va_start(ap, fmt);
   n = mg_vsnprintf(block->conn, added, (size_t) space, fmt, ap);
   va_end(ap);
 
   // Make sure we do not overflow buffer and the envp array
   if (n > 0 && n + 1 < space &&
       block->nvars < (int) ARRAY_SIZE(block->vars) - 2) {
     // Append a pointer to the added string into the envp array
     block->vars[block->nvars++] = added;
     // Bump up used length counter. Include \0 terminator
     block->len += n + 1;
   } else {
     cry(block->conn, "%s: CGI env buffer truncated for [%s]", __func__, fmt);
   }
 
   return added;
 }
 
 static void prepare_cgi_environment(struct mg_connection *conn,
                                     const char *prog,
                                     struct cgi_env_block *blk) {
   const char *s, *slash;
   struct vec var_vec;
   char *p, src_addr[IP_ADDR_STR_LEN];
   int  i;
 
   blk->len = blk->nvars = 0;
   blk->conn = conn;
   sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
 
   addenv(blk, "SERVER_NAME=%s", conn->ctx->config[AUTHENTICATION_DOMAIN]);
   addenv(blk, "SERVER_ROOT=%s", conn->ctx->config[DOCUMENT_ROOT]);
   addenv(blk, "DOCUMENT_ROOT=%s", conn->ctx->config[DOCUMENT_ROOT]);
   addenv(blk, "SERVER_SOFTWARE=%s/%s", "Mongoose", mg_version());
 
   // Prepare the environment block
   addenv(blk, "%s", "GATEWAY_INTERFACE=CGI/1.1");
   addenv(blk, "%s", "SERVER_PROTOCOL=HTTP/1.1");
   addenv(blk, "%s", "REDIRECT_STATUS=200"); // For PHP
 
   // TODO(lsm): fix this for IPv6 case
   addenv(blk, "SERVER_PORT=%d", ntohs(conn->client.lsa.sin.sin_port));
 
   addenv(blk, "REQUEST_METHOD=%s", conn->request_info.request_method);
   addenv(blk, "REMOTE_ADDR=%s", src_addr);
   addenv(blk, "REMOTE_PORT=%d", conn->request_info.remote_port);
   addenv(blk, "REQUEST_URI=%s", conn->request_info.uri);
 
   // SCRIPT_NAME
   assert(conn->request_info.uri[0] == '/');
   slash = strrchr(conn->request_info.uri, '/');
   if ((s = strrchr(prog, '/')) == NULL)
     s = prog;
   addenv(blk, "SCRIPT_NAME=%.*s%s", (int) (slash - conn->request_info.uri),
          conn->request_info.uri, s);
 
   addenv(blk, "SCRIPT_FILENAME=%s", prog);
   addenv(blk, "PATH_TRANSLATED=%s", prog);
   addenv(blk, "HTTPS=%s", conn->ssl == NULL ? "off" : "on");
 
   if ((s = mg_get_header(conn, "Content-Type")) != NULL)
     addenv(blk, "CONTENT_TYPE=%s", s);
 
   if (conn->request_info.query_string != NULL)
     addenv(blk, "QUERY_STRING=%s", conn->request_info.query_string);
 
   if ((s = mg_get_header(conn, "Content-Length")) != NULL)
     addenv(blk, "CONTENT_LENGTH=%s", s);
 
   if ((s = getenv("PATH")) != NULL)
     addenv(blk, "PATH=%s", s);
 
   if (conn->path_info != NULL) {
     addenv(blk, "PATH_INFO=%s", conn->path_info);
   }
 
 #if defined(_WIN32)
   if ((s = getenv("COMSPEC")) != NULL) {
     addenv(blk, "COMSPEC=%s", s);
   }
   if ((s = getenv("SYSTEMROOT")) != NULL) {
     addenv(blk, "SYSTEMROOT=%s", s);
   }
   if ((s = getenv("SystemDrive")) != NULL) {
     addenv(blk, "SystemDrive=%s", s);
   }
   if ((s = getenv("ProgramFiles")) != NULL) {
     addenv(blk, "ProgramFiles=%s", s);
   }
   if ((s = getenv("ProgramFiles(x86)")) != NULL) {
     addenv(blk, "ProgramFiles(x86)=%s", s);
   }
 #else
   if ((s = getenv("LD_LIBRARY_PATH")) != NULL)
     addenv(blk, "LD_LIBRARY_PATH=%s", s);
 #endif // _WIN32
 
   if ((s = getenv("PERLLIB")) != NULL)
     addenv(blk, "PERLLIB=%s", s);
 
   if (conn->request_info.remote_user != NULL) {
     addenv(blk, "REMOTE_USER=%s", conn->request_info.remote_user);
     addenv(blk, "%s", "AUTH_TYPE=Digest");
   }
 
   // Add all headers as HTTP_* variables
   for (i = 0; i < conn->request_info.num_headers; i++) {
     p = addenv(blk, "HTTP_%s=%s",
         conn->request_info.http_headers[i].name,
         conn->request_info.http_headers[i].value);
 
     // Convert variable name into uppercase, and change - to _
     for (; *p != '=' && *p != '\0'; p++) {
       if (*p == '-')
         *p = '_';
       *p = (char) toupper(* (unsigned char *) p);
     }
   }
 
   // Add user-specified variables
   s = conn->ctx->config[CGI_ENVIRONMENT];
   while ((s = next_option(s, &var_vec, NULL)) != NULL) {
     addenv(blk, "%.*s", (int) var_vec.len, var_vec.ptr);
   }
 
   blk->vars[blk->nvars++] = NULL;
   blk->buf[blk->len++] = '\0';
 
   assert(blk->nvars < (int) ARRAY_SIZE(blk->vars));
   assert(blk->len > 0);
   assert(blk->len < (int) sizeof(blk->buf));
 }
 
 static void handle_cgi_request(struct mg_connection *conn, const char *prog) {
   int headers_len, data_len, i, fdin[2], fdout[2];
   const char *status, *status_text;
   char buf[16384], *pbuf, dir[PATH_MAX], *p;
   struct mg_request_info ri;
   struct cgi_env_block blk;
   FILE *in = NULL, *out = NULL;
   struct file fout = STRUCT_FILE_INITIALIZER;
   pid_t pid = (pid_t) -1;
 
   prepare_cgi_environment(conn, prog, &blk);
 
   // 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, dir, sizeof(dir), "%s", prog);
   if ((p = strrchr(dir, '/')) != NULL) {
     *p++ = '\0';
   } else {
     dir[0] = '.', dir[1] = '\0';
     p = (char *) prog;
   }
 
   if (pipe(fdin) != 0 || pipe(fdout) != 0) {
     send_http_error(conn, 500, http_500_error,
         "Cannot create CGI pipe: %s", strerror(ERRNO));
     goto done;
   }
 
   pid = spawn_process(conn, p, blk.buf, blk.vars, fdin[0], fdout[1], dir);
   if (pid == (pid_t) -1) {
     send_http_error(conn, 500, http_500_error,
         "Cannot spawn CGI process [%s]: %s", prog, strerror(ERRNO));
     goto done;
   }
 
   // Make sure child closes all pipe descriptors. It must dup them to 0,1
   set_close_on_exec(fdin[0]);
   set_close_on_exec(fdin[1]);
   set_close_on_exec(fdout[0]);
   set_close_on_exec(fdout[1]);
 
   // 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]);
   fdin[0] = fdout[1] = -1;
 
 
   if ((in = fdopen(fdin[1], "wb")) == NULL ||
       (out = fdopen(fdout[0], "rb")) == NULL) {
     send_http_error(conn, 500, http_500_error,
         "fopen: %s", strerror(ERRNO));
     goto done;
   }
 
   setbuf(in, NULL);
   setbuf(out, NULL);
   fout.fp = out;
 
   // Send POST data to the CGI process if needed
   if (!strcmp(conn->request_info.request_method, "POST") &&
       !forward_body_data(conn, in, INVALID_SOCKET, NULL)) {
     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;
   headers_len = read_request(out, conn, buf, sizeof(buf), &data_len);
   if (headers_len <= 0) {
     send_http_error(conn, 500, http_500_error,
                     "CGI program sent malformed or too big (>%u bytes) "
                     "HTTP headers: [%.*s]",
                     (unsigned) sizeof(buf), data_len, buf);
     goto done;
   }
   pbuf = buf;
   buf[headers_len - 1] = '\0';
   parse_http_headers(&pbuf, &ri);
 
   // Make up and send the status line
   status_text = "OK";
   if ((status = get_header(&ri, "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, "Location") != NULL) {
     conn->status_code = 302;
   } else {
     conn->status_code = 200;
   }
   if (get_header(&ri, "Connection") != NULL &&
       !mg_strcasecmp(get_header(&ri, "Connection"), "keep-alive")) {
     conn->must_close = 1;
   }
   (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++) {
     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
   conn->num_bytes_sent += mg_write(conn, buf + headers_len,
                                    (size_t)(data_len - headers_len));
 
   // Read the rest of CGI output and send to the client
   send_file_data(conn, &fout, 0, INT64_MAX);
 
 done:
   if (pid != (pid_t) -1) {
     kill(pid, SIGKILL);
   }
   if (fdin[0] != -1) {
     close(fdin[0]);
   }
   if (fdout[1] != -1) {
     close(fdout[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]);
   }
 }
 #endif // !NO_CGI
 
 // For a given PUT path, create all intermediate subdirectories
 // for given path. Return 0 if the path itself is a directory,
 // or -1 on error, 1 if OK.
 static int put_dir(struct mg_connection *conn, const char *path) {
   char buf[PATH_MAX];
   const char *s, *p;
   struct file file = STRUCT_FILE_INITIALIZER;
   int len, res = 1;
 
   for (s = p = path + 2; (p = strchr(s, '/')) != NULL; s = ++p) {
     len = p - path;
     if (len >= (int) sizeof(buf)) {
       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) && mg_mkdir(buf, 0755) != 0) {
       res = -1;
       break;
     }
 
     // Is path itself a directory?
     if (p[1] == '\0') {
       res = 0;
     }
   }
 
   return res;
 }
 
 static void mkcol(struct mg_connection *conn, const char *path) {
   int rc, body_len;
   struct de de;
   memset(&de.file, 0, sizeof(de.file));
   mg_stat(conn, path, &de.file);
 
   if(de.file.modification_time) {
       send_http_error(conn, 405, "Method Not Allowed",
                       "mkcol(%s): %s", path, strerror(ERRNO));
       return;
   }
 
   body_len = conn->data_len - conn->request_len;
   if(body_len > 0) {
       send_http_error(conn, 415, "Unsupported media type",
                       "mkcol(%s): %s", path, strerror(ERRNO));
       return;
   }
 
   rc = mg_mkdir(path, 0755);
 
   if (rc == 0) {
     conn->status_code = 201;
     mg_printf(conn, "HTTP/1.1 %d Created\r\n\r\n", conn->status_code);
   } else if (rc == -1) {
       if(errno == EEXIST)
         send_http_error(conn, 405, "Method Not Allowed",
                       "mkcol(%s): %s", path, strerror(ERRNO));
       else if(errno == EACCES)
           send_http_error(conn, 403, "Forbidden",
                         "mkcol(%s): %s", path, strerror(ERRNO));
       else if(errno == ENOENT)
           send_http_error(conn, 409, "Conflict",
                         "mkcol(%s): %s", path, strerror(ERRNO));
       else
           send_http_error(conn, 500, http_500_error,
                           "fopen(%s): %s", path, strerror(ERRNO));
   }
 }
 
 static void put_file(struct mg_connection *conn, const char *path) {
   struct file file = STRUCT_FILE_INITIALIZER;
   const char *range;
   int64_t r1, r2;
   int rc;
 
   conn->status_code = mg_stat(conn, path, &file) ? 200 : 201;
 
   if ((rc = put_dir(conn, path)) == 0) {
     mg_printf(conn, "HTTP/1.1 %d OK\r\n\r\n", conn->status_code);
   } else if (rc == -1) {
     send_http_error(conn, 500, http_500_error,
                     "put_dir(%s): %s", path, strerror(ERRNO));
   } else if (!mg_fopen(conn, path, "wb+", &file) || file.fp == NULL) {
     mg_fclose(&file);
     send_http_error(conn, 500, http_500_error,
                     "fopen(%s): %s", path, strerror(ERRNO));
   } else {
     fclose_on_exec(&file);
     range = mg_get_header(conn, "Content-Range");
     r1 = r2 = 0;
     if (range != NULL && parse_range_header(range, &r1, &r2) > 0) {
       conn->status_code = 206;
       fseeko(file.fp, r1, SEEK_SET);
     }
     if (!forward_body_data(conn, file.fp, INVALID_SOCKET, NULL)) {
       conn->status_code = 500;
     }
     mg_printf(conn, "HTTP/1.1 %d OK\r\nContent-Length: 0\r\n\r\n",
               conn->status_code);
     mg_fclose(&file);
   }
 }
 
 static void send_ssi_file(struct mg_connection *, const char *,
                           struct 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[PATH_MAX], *p;
   struct file file = STRUCT_FILE_INITIALIZER;
 
   // 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=\"%[^\"]\"", file_name) == 1) {
     // File name is relative to the webserver root
     (void) mg_snprintf(conn, path, sizeof(path), "%s%c%s",
         conn->ctx->config[DOCUMENT_ROOT], '/', file_name);
   } else if (sscanf(tag, " abspath=\"%[^\"]\"", file_name) == 1) {
     // File name is relative to the webserver working directory
     // or it is absolute system path
     (void) mg_snprintf(conn, path, sizeof(path), "%s", file_name);
   } else if (sscanf(tag, " file=\"%[^\"]\"", file_name) == 1 ||
              sscanf(tag, " \"%[^\"]\"", file_name) == 1) {
     // File name is relative to the currect document
     (void) mg_snprintf(conn, path, sizeof(path), "%s", ssi);
     if ((p = strrchr(path, '/')) != NULL) {
       p[1] = '\0';
     }
     (void) mg_snprintf(conn, path + strlen(path),
         sizeof(path) - strlen(path), "%s", file_name);
   } else {
     cry(conn, "Bad SSI #include: [%s]", tag);
     return;
   }
 
   if (!mg_fopen(conn, path, "rb", &file)) {
     cry(conn, "Cannot open SSI #include: [%s]: fopen(%s): %s",
         tag, path, strerror(ERRNO));
   } else {
     fclose_on_exec(&file);
     if (match_prefix(conn->ctx->config[SSI_EXTENSIONS],
                      strlen(conn->ctx->config[SSI_EXTENSIONS]), path) > 0) {
       send_ssi_file(conn, path, &file, include_level + 1);
     } else {
       send_file_data(conn, &file, 0, INT64_MAX);
     }
     mg_fclose(&file);
   }
 }
 
 #if !defined(NO_POPEN)
 static void do_ssi_exec(struct mg_connection *conn, char *tag) {
   char cmd[MG_BUF_LEN];
   struct file file = STRUCT_FILE_INITIALIZER;
 
   if (sscanf(tag, " \"%[^\"]\"", cmd) != 1) {
     cry(conn, "Bad SSI #exec: [%s]", tag);
   } else if ((file.fp = popen(cmd, "r")) == NULL) {
     cry(conn, "Cannot SSI #exec: [%s]: %s", cmd, strerror(ERRNO));
   } else {
     send_file_data(conn, &file, 0, INT64_MAX);
     pclose(file.fp);
   }
 }
 #endif // !NO_POPEN
 
 static int mg_fgetc(struct file *filep, int offset) {
   if (filep->membuf != NULL && offset >=0 && offset < filep->size) {
     return ((unsigned char *) filep->membuf)[offset];
   } else if (filep->fp != NULL) {
     return fgetc(filep->fp);
   } else {
     return EOF;
   }
 }
 
 static void send_ssi_file(struct mg_connection *conn, const char *path,
                           struct file *filep, int include_level) {
   char buf[MG_BUF_LEN];
   int ch, offset, len, in_ssi_tag;
 
   if (include_level > 10) {
     cry(conn, "SSI #include level is too deep (%s)", path);
     return;
   }
 
   in_ssi_tag = len = offset = 0;
   while ((ch = mg_fgetc(filep, offset)) != EOF) {
     if (in_ssi_tag && ch == '>') {
       in_ssi_tag = 0;
       buf[len++] = (char) ch;
       buf[len] = '\0';
       assert(len <= (int) sizeof(buf));
       if (len < 6 || memcmp(buf, "<!--#", 5) != 0) {
         // Not an SSI tag, pass it
         (void) mg_write(conn, buf, (size_t) len);
       } else {
         if (!memcmp(buf + 5, "include", 7)) {
           do_ssi_include(conn, path, buf + 12, include_level);
 #if !defined(NO_POPEN)
         } else if (!memcmp(buf + 5, "exec", 4)) {
           do_ssi_exec(conn, buf + 9);
 #endif // !NO_POPEN
         } else {
           cry(conn, "%s: unknown SSI " "command: \"%s\"", path, buf);
         }
       }
       len = 0;
     } else if (in_ssi_tag) {
       if (len == 5 && memcmp(buf, "<!--#", 5) != 0) {
         // Not an SSI tag
         in_ssi_tag = 0;
       } else if (len == (int) sizeof(buf) - 2) {
         cry(conn, "%s: SSI tag is too large", path);
         len = 0;
       }
       buf[len++] = ch & 0xff;
     } else if (ch == '<') {
       in_ssi_tag = 1;
       if (len > 0) {
         mg_write(conn, buf, (size_t) len);
       }
       len = 0;
       buf[len++] = ch & 0xff;
     } else {
       buf[len++] = ch & 0xff;
       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 file file = STRUCT_FILE_INITIALIZER;
 
   if (!mg_fopen(conn, path, "rb", &file)) {
     send_http_error(conn, 500, http_500_error, "fopen(%s): %s", path,
                     strerror(ERRNO));
   } else {
     conn->must_close = 1;
     fclose_on_exec(&file);
     mg_printf(conn, "HTTP/1.1 200 OK\r\n"
               "Content-Type: text/html\r\nConnection: %s\r\n\r\n",
               suggest_connection_header(conn));
     send_ssi_file(conn, path, &file, 0);
     mg_fclose(&file);
   }
 }
 
 static void send_options(struct mg_connection *conn) {
   conn->status_code = 200;
 
   mg_printf(conn, "%s", "HTTP/1.1 200 OK\r\n"
             "Allow: GET, POST, HEAD, CONNECT, PUT, DELETE, OPTIONS, PROPFIND, MKCOL\r\n"
             "DAV: 1\r\n\r\n");
 }
 
 // Writes PROPFIND properties for a collection element
 static void print_props(struct mg_connection *conn, const char* uri,
                         struct file *filep) {
   char mtime[64];
   gmt_time_string(mtime, sizeof(mtime), &filep->modification_time);
   conn->num_bytes_sent += 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:prop>"
         "<d:status>HTTP/1.1 200 OK</d:status>"
        "</d:propstat>"
       "</d:response>\n",
       uri,
       filep->is_directory ? "<d:collection/>" : "",
       filep->size,
       mtime);
 }
 
 static void print_dav_dir_entry(struct de *de, void *data) {
   char href[PATH_MAX];
   char href_encoded[PATH_MAX];
   struct mg_connection *conn = (struct mg_connection *) data;
   mg_snprintf(conn, href, sizeof(href), "%s%s",
               conn->request_info.uri, de->file_name);
   mg_url_encode(href, href_encoded, PATH_MAX-1);
   print_props(conn, href_encoded, &de->file);
 }
 
 static void handle_propfind(struct mg_connection *conn, const char *path,
                             struct file *filep) {
   const char *depth = mg_get_header(conn, "Depth");
 
   conn->must_close = 1;
   conn->status_code = 207;
   mg_printf(conn, "HTTP/1.1 207 Multi-Status\r\n"
             "Connection: close\r\n"
             "Content-Type: text/xml; charset=utf-8\r\n\r\n");
 
   conn->num_bytes_sent += 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.uri, filep);
 
   // If it is a directory, print directory entries too if Depth is not 0
   if (filep->is_directory &&
       !mg_strcasecmp(conn->ctx->config[ENABLE_DIRECTORY_LISTING], "yes") &&
       (depth == NULL || strcmp(depth, "0") != 0)) {
     scan_directory(conn, path, conn, &print_dav_dir_entry);
   }
 
   conn->num_bytes_sent += mg_printf(conn, "%s\n", "</d:multistatus>");
 }
 
 #if defined(USE_WEBSOCKET)
 
 // START OF SHA-1 code
 // Copyright(c) By Steve Reid <steve@edmweb.com>
 #define SHA1HANDSOFF
 #if defined(__sun)
 #include "solarisfixes.h"
 #endif
 
 union char64long16 { unsigned char c[64]; uint32_t l[16]; };
 
 #define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))
 
 static uint32_t blk0(union char64long16 *block, int i) {
   // Forrest: SHA expect BIG_ENDIAN, swap if LITTLE_ENDIAN
   if (!is_big_endian()) {
     block->l[i] = (rol(block->l[i], 24) & 0xFF00FF00) |
       (rol(block->l[i], 8) & 0x00FF00FF);
   }
   return block->l[i];
 }
 
 #define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
     ^block->l[(i+2)&15]^block->l[i&15],1))
 #define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(block, i)+0x5A827999+rol(v,5);w=rol(w,30);
 #define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
 #define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
 #define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
 #define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);
 
 typedef struct {
     uint32_t state[5];
     uint32_t count[2];
     unsigned char buffer[64];
 } SHA1_CTX;
 
 static void SHA1Transform(uint32_t state[5], const unsigned char buffer[64]) {
   uint32_t a, b, c, d, e;
   union char64long16 block[1];
 
   memcpy(block, buffer, 64);
   a = state[0];
   b = state[1];
   c = state[2];
   d = state[3];
   e = state[4];
   R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
   R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
   R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
   R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
   R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
   R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
   R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
   R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
   R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
   R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
   R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
   R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
   R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
   R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
   R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
   R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
   R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
   R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
   R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
   R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
   state[0] += a;
   state[1] += b;
   state[2] += c;
   state[3] += d;
   state[4] += e;
   a = b = c = d = e = 0;
   memset(block, '\0', sizeof(block));
 }
 
 static void SHA1Init(SHA1_CTX* context) {
   context->state[0] = 0x67452301;
   context->state[1] = 0xEFCDAB89;
   context->state[2] = 0x98BADCFE;
   context->state[3] = 0x10325476;
   context->state[4] = 0xC3D2E1F0;
   context->count[0] = context->count[1] = 0;
 }
 
 static void SHA1Update(SHA1_CTX* context, const unsigned char* data,
                        uint32_t len) {
   uint32_t i, j;
 
   j = context->count[0];
   if ((context->count[0] += len << 3) < j)
     context->count[1]++;
   context->count[1] += (len>>29);
   j = (j >> 3) & 63;
   if ((j + len) > 63) {
     memcpy(&context->buffer[j], data, (i = 64-j));
     SHA1Transform(context->state, context->buffer);
     for ( ; i + 63 < len; i += 64) {
       SHA1Transform(context->state, &data[i]);
     }
     j = 0;
   }
   else i = 0;
   memcpy(&context->buffer[j], &data[i], len - i);
 }
 
 static void SHA1Final(unsigned char digest[20], SHA1_CTX* context) {
   unsigned i;
   unsigned char finalcount[8], c;
 
   for (i = 0; i < 8; i++) {
     finalcount[i] = (unsigned char)((context->count[(i >= 4 ? 0 : 1)]
                                      >> ((3-(i & 3)) * 8) ) & 255);
   }
   c = 0200;
   SHA1Update(context, &c, 1);
   while ((context->count[0] & 504) != 448) {
     c = 0000;
     SHA1Update(context, &c, 1);
   }
   SHA1Update(context, finalcount, 8);
   for (i = 0; i < 20; i++) {
     digest[i] = (unsigned char)
       ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
   }
   memset(context, '\0', sizeof(*context));
   memset(&finalcount, '\0', sizeof(finalcount));
 }
 // END OF SHA1 CODE
 
 static void base64_encode(const unsigned char *src, int src_len, char *dst) {
   static const char *b64 =
     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
   int i, j, a, b, c;
 
   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';
 }
 
 static void send_websocket_handshake(struct mg_connection *conn) {
   static const char *magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
   char buf[100], sha[20], b64_sha[sizeof(sha) * 2];
   SHA1_CTX sha_ctx;
 
   mg_snprintf(conn, buf, sizeof(buf), "%s%s",
               mg_get_header(conn, "Sec-WebSocket-Key"), magic);
   SHA1Init(&sha_ctx);
   SHA1Update(&sha_ctx, (unsigned char *) buf, strlen(buf));
   SHA1Final((unsigned char *) sha, &sha_ctx);
   base64_encode((unsigned char *) sha, sizeof(sha), b64_sha);
   mg_printf(conn, "%s%s%s",
             "HTTP/1.1 101 Switching Protocols\r\n"
             "Upgrade: websocket\r\n"
             "Connection: Upgrade\r\n"
             "Sec-WebSocket-Accept: ", b64_sha, "\r\n\r\n");
 }
 
 static void read_websocket(struct mg_connection *conn) {
   // 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 bits, n, stop = 0;
   size_t i, len, mask_len, data_len, header_len, body_len;
   // 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.
   char mem[4 * 1024], mask[4], *data;
 
   assert(conn->content_len == 0);
 
   // Loop continuously, reading messages from the socket, invoking the callback,
   // and waiting repeatedly until an error occurs.
   while (!stop) {
     header_len = 0;
     // 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
     if ((body_len = 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) {
         data_len = len;
         header_len = 2 + mask_len;
       } else if (len == 126 && body_len >= 4 + mask_len) {
         header_len = 4 + mask_len;
         data_len = ((((int) buf[2]) << 8) + buf[3]);
       } else if (body_len >= 10 + mask_len) {
         header_len = 10 + mask_len;
         data_len = (((uint64_t) htonl(* (uint32_t *) &buf[2])) << 32) +
           htonl(* (uint32_t *) &buf[6]);
       }
     }
 
     // Data layout is as follows:
     //  conn->buf               buf
     //     v                     v              frame1           | frame2
     //     |---------------------|----------------|--------------|-------
     //     |                     |<--header_len-->|<--data_len-->|
     //     |<-conn->request_len->|<-----body_len----------->|
     //     |<-------------------conn->data_len------------->|
 
     if (header_len > 0) {
       // Allocate space to hold websocket payload
       data = mem;
       if (data_len > sizeof(mem) && (data = malloc(data_len)) == NULL) {
         // Allocation failed, exit the loop and then close the connection
         // TODO: notify user about the failure
         break;
       }
 
       // Save mask and bits, otherwise it may be clobbered by memmove below
       bits = buf[0];
       memcpy(mask, buf + header_len - mask_len, mask_len);
 
       // Read frame payload into the allocated buffer.
       assert(body_len >= header_len);
       if (data_len + header_len > body_len) {
         len = body_len - header_len;
         memcpy(data, buf + header_len, len);
         // TODO: handle pull error
         pull_all(NULL, conn, data + len, data_len - len);
         conn->data_len = conn->request_len;
       } else {
         len = data_len + header_len;
         memcpy(data, buf + header_len, data_len);
         memmove(buf, buf + len, body_len - len);
         conn->data_len -= len;
       }
 
       // Apply mask if necessary
       if (mask_len > 0) {
         for (i = 0; i < data_len; i++) {
           data[i] ^= mask[i % 4];
         }
       }
 
       // Exit the loop if callback signalled to exit,
       // or "connection close" opcode received.
       if ((bits & WEBSOCKET_OPCODE_CONNECTION_CLOSE) ||
           (conn->ctx->callbacks.websocket_data != NULL &&
            !conn->ctx->callbacks.websocket_data(conn, bits, data, data_len))) {
         stop = 1;
       }
 
       if (data != mem) {
         free(data);
       }
       // Not breaking the loop, process next websocket frame.
     } else {
       // Buffering websocket request
       if ((n = pull(NULL, conn, conn->buf + conn->data_len,
                     conn->buf_size - conn->data_len)) <= 0) {
         break;
       }
       conn->data_len += n;
     }
   }
 }
 
 int mg_websocket_write(struct mg_connection* conn, int opcode,
                        const char *data, size_t data_len) {
     unsigned char *copy;
     size_t copy_len = 0;
     int retval = -1;
 
     if ((copy = (unsigned char *) malloc(data_len + 10)) == NULL) {
       return -1;
     }
 
     copy[0] = 0x80 + (opcode & 0x0f);
 
     // Frame format: http://tools.ietf.org/html/rfc6455#section-5.2
     if (data_len < 126) {
       // Inline 7-bit length field
       copy[1] = data_len;
       memcpy(copy + 2, data, data_len);
       copy_len = 2 + data_len;
     } else if (data_len <= 0xFFFF) {
       // 16-bit length field
       copy[1] = 126;
       * (uint16_t *) (copy + 2) = htons(data_len);
       memcpy(copy + 4, data, data_len);
       copy_len = 4 + data_len;
     } else {
       // 64-bit length field
       copy[1] = 127;
       * (uint32_t *) (copy + 2) = htonl((uint64_t) data_len >> 32);
       * (uint32_t *) (copy + 6) = htonl(data_len & 0xffffffff);
       memcpy(copy + 10, data, data_len);
       copy_len = 10 + data_len;
     }
 
     // Not thread safe
     if (copy_len > 0) {
       retval = mg_write(conn, copy, copy_len);
     }
     free(copy);
 
     return retval;
 }
 
 static void handle_websocket_request(struct mg_connection *conn) {
   const char *version = mg_get_header(conn, "Sec-WebSocket-Version");
   if (version == NULL || strcmp(version, "13") != 0) {
     send_http_error(conn, 426, "Upgrade Required", "%s", "Upgrade Required");
   } else if (conn->ctx->callbacks.websocket_connect != NULL &&
              conn->ctx->callbacks.websocket_connect(conn) != 0) {
     // Callback has returned non-zero, do not proceed with handshake
   } else {
     send_websocket_handshake(conn);
     if (conn->ctx->callbacks.websocket_ready != NULL) {
       conn->ctx->callbacks.websocket_ready(conn);
     }
     read_websocket(conn);
   }
 }
 
 static int is_websocket_request(const struct mg_connection *conn) {
   const char *host, *upgrade, *connection, *version, *key;
 
   host = mg_get_header(conn, "Host");
   upgrade = mg_get_header(conn, "Upgrade");
   connection = mg_get_header(conn, "Connection");
   key = mg_get_header(conn, "Sec-WebSocket-Key");
   version = mg_get_header(conn, "Sec-WebSocket-Version");
 
   return host != NULL && upgrade != NULL && connection != NULL &&
     key != NULL && version != NULL &&
     mg_strcasestr(upgrade, "websocket") != NULL &&
     mg_strcasestr(connection, "Upgrade") != NULL;
 }
 #endif // !USE_WEBSOCKET
 
 static int isbyte(int n) {
   return n >= 0 && n <= 255;
 }
 
 static int parse_net(const char *spec, uint32_t *net, uint32_t *mask) {
   int n, a, b, c, d, slash = 32, len = 0;
 
   if ((sscanf(spec, "%d.%d.%d.%d/%d%n", &a, &b, &c, &d, &slash, &n) == 5 ||
       sscanf(spec, "%d.%d.%d.%d%n", &a, &b, &c, &d, &n) == 4) &&
       isbyte(a) && isbyte(b) && isbyte(c) && isbyte(d) &&
       slash >= 0 && slash < 33) {
     len = n;
     *net = ((uint32_t)a << 24) | ((uint32_t)b << 16) | ((uint32_t)c << 8) | d;
     *mask = slash ? 0xffffffffU << (32 - slash) : 0;
   }
 
   return len;
 }
 
 static int set_throttle(const char *spec, uint32_t remote_ip, const char *uri) {
   int throttle = 0;
   struct vec vec, val;
   uint32_t net, mask;
   char mult;
   double v;
 
   while ((spec = next_option(spec, &vec, &val)) != NULL) {
     mult = ',';
     if (sscanf(val.ptr, "%lf%c", &v, &mult) < 1 || 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 if (parse_net(vec.ptr, &net, &mask) > 0) {
       if ((remote_ip & mask) == net) {
         throttle = (int) v;
       }
     } else if (match_prefix(vec.ptr, vec.len, uri) > 0) {
       throttle = (int) v;
     }
   }
 
   return throttle;
 }
 
 static uint32_t get_remote_ip(const struct mg_connection *conn) {
   return ntohl(* (uint32_t *) &conn->client.rsa.sin.sin_addr);
 }
 
 #ifdef USE_LUA
 #include "mod_lua.c"
 #endif // USE_LUA
 
 int mg_upload(struct mg_connection *conn, const char *destination_dir) {
   const char *content_type_header, *boundary_start;
   char buf[MG_BUF_LEN], path[PATH_MAX], fname[1024], boundary[100], *s;
   FILE *fp;
   int bl, n, i, j, headers_len, boundary_len, eof,
       len = 0, num_uploaded_files = 0;
 
   // Request looks like this:
   //
   // POST /upload HTTP/1.1
   // Host: 127.0.0.1:8080
   // Content-Length: 244894
   // Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryRVr
   //
   // ------WebKitFormBoundaryRVr
   // Content-Disposition: form-data; name="file"; filename="accum.png"
   // Content-Type: image/png
   //
   //  <89>PNG
   //  <PNG DATA>
   // ------WebKitFormBoundaryRVr
 
   // Extract boundary string from the Content-Type header
   if ((content_type_header = mg_get_header(conn, "Content-Type")) == NULL ||
       (boundary_start = mg_strcasestr(content_type_header,
                                       "boundary=")) == NULL ||
       (sscanf(boundary_start, "boundary=\"%99[^\"]\"", boundary) == 0 &&
        sscanf(boundary_start, "boundary=%99s", boundary) == 0) ||
       boundary[0] == '\0') {
     return num_uploaded_files;
   }
 
   boundary_len = strlen(boundary);
   bl = boundary_len + 4;  // \r\n--<boundary>
   for (;;) {
     // Pull in headers
     assert(len >= 0 && len <= (int) sizeof(buf));
     while ((n = mg_read(conn, buf + len, sizeof(buf) - len)) > 0) {
       len += n;
     }
     if ((headers_len = get_request_len(buf, len)) <= 0) {
       break;
     }
 
     // Fetch file name.
     fname[0] = '\0';
     for (i = j = 0; i < headers_len; i++) {
       if (buf[i] == '\r' && buf[i + 1] == '\n') {
         buf[i] = buf[i + 1] = '\0';
         // TODO(lsm): don't expect filename to be the 3rd field,
         // parse the header properly instead.
         sscanf(&buf[j], "Content-Disposition: %*s %*s filename=\"%1023[^\"]",
                fname);
         j = i + 2;
       }
     }
 
     // Give up if the headers are not what we expect
     if (fname[0] == '\0') {
       break;
     }
 
     // Move data to the beginning of the buffer
     assert(len >= headers_len);
     memmove(buf, &buf[headers_len], len - headers_len);
     len -= headers_len;
 
     // We open the file with exclusive lock held. This guarantee us
     // there is no other thread can save into the same file simultaneously.
     fp = NULL;
     // Construct destination file name. Do not allow paths to have slashes.
     if ((s = strrchr(fname, '/')) == NULL &&
         (s = strrchr(fname, '\\')) == NULL) {
       s = fname;
     }
 
     // Open file in binary mode. TODO: set an exclusive lock.
     snprintf(path, sizeof(path), "%s/%s", destination_dir, s);
     if ((fp = fopen(path, "wb")) == NULL) {
       break;
     }
 
     // Read POST data, write into file until boundary is found.
     eof = n = 0;
     do {
       len += n;
       for (i = 0; i < len - bl; i++) {
         if (!memcmp(&buf[i], "\r\n--", 4) &&
             !memcmp(&buf[i + 4], boundary, boundary_len)) {
           // Found boundary, that's the end of file data.
           fwrite(buf, 1, i, fp);
           eof = 1;
           memmove(buf, &buf[i + bl], len - (i + bl));
           len -= i + bl;
           break;
         }
       }
       if (!eof && len > bl) {
         fwrite(buf, 1, len - bl, fp);
         memmove(buf, &buf[len - bl], bl);
         len = bl;
       }
     } while (!eof && (n = mg_read(conn, buf + len, sizeof(buf) - len)) > 0);
     fclose(fp);
     if (eof) {
       num_uploaded_files++;
       if (conn->ctx->callbacks.upload != NULL) {
         conn->ctx->callbacks.upload(conn, path);
       }
     }
   }
 
   return num_uploaded_files;
 }
 
 static int is_put_or_delete_request(const struct mg_connection *conn) {
   const char *s = conn->request_info.request_method;
   return s != NULL && (!strcmp(s, "PUT") ||
                        !strcmp(s, "DELETE") ||
                        !strcmp(s, "MKCOL"));
 }
 
 static int get_first_ssl_listener_index(const struct mg_context *ctx) {
   int i, index = -1;
   for (i = 0; index == -1 && i < ctx->num_listening_sockets; i++) {
     index = ctx->listening_sockets[i].is_ssl ? i : -1;
   }
   return index;
 }
 
 static void redirect_to_https_port(struct mg_connection *conn, int ssl_index) {
   char host[1025];
   const char *host_header;
 
   if ((host_header = mg_get_header(conn, "Host")) == NULL ||
       sscanf(host_header, "%1024[^:]", host) == 0) {
     // Cannot get host from the Host: header. Fallback to our IP address.
     sockaddr_to_string(host, sizeof(host), &conn->client.lsa);
   }
 
   mg_printf(conn, "HTTP/1.1 302 Found\r\nLocation: https://%s:%d%s\r\n\r\n",
             host, (int) ntohs(conn->ctx->listening_sockets[ssl_index].
                               lsa.sin.sin_port), conn->request_info.uri);
 }
 
 // This is the heart of the Mongoose's logic.
 // This function is called when the request is read, parsed and validated,
 // and Mongoose 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[PATH_MAX];
   int uri_len, ssl_index;
   struct file file = STRUCT_FILE_INITIALIZER;
 
   if ((conn->request_info.query_string = strchr(ri->uri, '?')) != NULL) {
     * ((char *) conn->request_info.query_string++) = '\0';
   }
   uri_len = (int) strlen(ri->uri);
   mg_url_decode(ri->uri, uri_len, (char *) ri->uri, uri_len + 1, 0);
   remove_double_dots_and_double_slashes((char *) ri->uri);
   convert_uri_to_file_name(conn, path, sizeof(path), &file);
   conn->throttle = set_throttle(conn->ctx->config[THROTTLE],
                                 get_remote_ip(conn), ri->uri);
 
   DEBUG_TRACE(("%s", ri->uri));
   // Perform redirect and auth checks before calling begin_request() handler.
   // Otherwise, begin_request() would need to perform auth checks and redirects.
   if (!conn->client.is_ssl && conn->client.ssl_redir &&
       (ssl_index = get_first_ssl_listener_index(conn->ctx)) > -1) {
     redirect_to_https_port(conn, ssl_index);
   } else if (!is_put_or_delete_request(conn) &&
              !check_authorization(conn, path)) {
     send_authorization_request(conn);
   } else if (conn->ctx->callbacks.begin_request != NULL &&
       conn->ctx->callbacks.begin_request(conn)) {
     // Do nothing, callback has served the request
 #if defined(USE_WEBSOCKET)
   } else if (is_websocket_request(conn)) {
     handle_websocket_request(conn);
 #endif
   } else if (!strcmp(ri->request_method, "OPTIONS")) {
     send_options(conn);
   } else if (conn->ctx->config[DOCUMENT_ROOT] == NULL) {
     send_http_error(conn, 404, "Not Found", "Not Found");
   } else if (is_put_or_delete_request(conn) &&
              (is_authorized_for_put(conn) != 1)) {
     send_authorization_request(conn);
   } else if (!strcmp(ri->request_method, "PUT")) {
     put_file(conn, path);
   } else if (!strcmp(ri->request_method, "MKCOL")) {
     mkcol(conn, path);
   } else if (!strcmp(ri->request_method, "DELETE")) {
       struct de de;
       memset(&de.file, 0, sizeof(de.file));
       if(!mg_stat(conn, path, &de.file)) {
           send_http_error(conn, 404, "Not Found", "%s", "File not found");
       } else {
           if(de.file.modification_time) {
               if(de.file.is_directory) {
                   remove_directory(conn, path);
                   send_http_error(conn, 204, "No Content", "%s", "");
               } else if (mg_remove(path) == 0) {
                   send_http_error(conn, 204, "No Content", "%s", "");
               } else {
                   send_http_error(conn, 423, "Locked", "remove(%s): %s", path,
                           strerror(ERRNO));
               }
           }
           else {
               send_http_error(conn, 500, http_500_error, "remove(%s): %s", path,
                     strerror(ERRNO));
           }
       }
   } else if ((file.membuf == NULL && file.modification_time == (time_t) 0) ||
              must_hide_file(conn, path)) {
     send_http_error(conn, 404, "Not Found", "%s", "File not found");
   } else if (file.is_directory && ri->uri[uri_len - 1] != '/') {
     mg_printf(conn, "HTTP/1.1 301 Moved Permanently\r\n"
               "Location: %s/\r\n\r\n", ri->uri);
   } else if (!strcmp(ri->request_method, "PROPFIND")) {
     handle_propfind(conn, path, &file);
   } else if (file.is_directory &&
              !substitute_index_file(conn, path, sizeof(path), &file)) {
     if (!mg_strcasecmp(conn->ctx->config[ENABLE_DIRECTORY_LISTING], "yes")) {
       handle_directory_request(conn, path);
     } else {
       send_http_error(conn, 403, "Directory Listing Denied",
           "Directory listing denied");
     }
 #ifdef USE_LUA
   } else if (match_prefix("**.lp$", 6, path) > 0) {
     handle_lsp_request(conn, path, &file, NULL);
 #endif
 #if !defined(NO_CGI)
   } else if (match_prefix(conn->ctx->config[CGI_EXTENSIONS],
                           strlen(conn->ctx->config[CGI_EXTENSIONS]),
                           path) > 0) {
     if (strcmp(ri->request_method, "POST") &&
         strcmp(ri->request_method, "HEAD") &&
         strcmp(ri->request_method, "GET")) {
       send_http_error(conn, 501, "Not Implemented",
                       "Method %s is not implemented", ri->request_method);
     } else {
       handle_cgi_request(conn, path);
     }
 #endif // !NO_CGI
   } else if (match_prefix(conn->ctx->config[SSI_EXTENSIONS],
                           strlen(conn->ctx->config[SSI_EXTENSIONS]),
                           path) > 0) {
     handle_ssi_file_request(conn, path);
   } else if (is_not_modified(conn, path, &file)) {
     send_http_error(conn, 304, "Not Modified", "%s", "");
   } else {
     handle_file_request(conn, path, &file);
   }
 }
 
 static void close_all_listening_sockets(struct mg_context *ctx) {
   int i;
   for (i = 0; i < ctx->num_listening_sockets; i++) {
     closesocket(ctx->listening_sockets[i].sock);
   }
   free(ctx->listening_sockets);
 }
 
 static int is_valid_port(unsigned int port) {
   return port > 0 && port < 0xffff;
 }
 
 // Valid listening port specification is: [ip_address:]port[s]
 // Examples: 80, 443s, 127.0.0.1:3128, 1.2.3.4:8080s
 // TODO(lsm): add parsing of the IPv6 address
 static int parse_port_string(const struct vec *vec, struct socket *so) {
   unsigned int a, b, c, d, ch, len, port;
 #if defined(USE_IPV6)
   char buf[100];
 #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;
 
   if (sscanf(vec->ptr, "%u.%u.%u.%u:%u%n", &a, &b, &c, &d, &port, &len) == 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);
 #if defined(USE_IPV6)
 
   } else if (sscanf(vec->ptr, "[%49[^]]]:%d%n", buf, &port, &len) == 2 &&
              inet_pton(AF_INET6, buf, &so->lsa.sin6.sin6_addr)) {
     // IPv6 address, e.g. [3ffe:2a00:100:7031::1]:8080
     so->lsa.sin6.sin6_family = AF_INET6;
     so->lsa.sin6.sin6_port = htons((uint16_t) port);
 #endif
   } else if (sscanf(vec->ptr, "%u%n", &port, &len) == 1) {
     // If only port is specified, bind to IPv4, INADDR_ANY
     so->lsa.sin.sin_port = htons((uint16_t) port);
   } else {
     port = len = 0;   // Parsing failure. Make port invalid.
   }
 
   ch = vec->ptr[len];  // Next character after the port number
   so->is_ssl = ch == 's';
   so->ssl_redir = ch == 'r';
 
   // Make sure the port is valid and vector ends with 's', 'r' or ','
   return is_valid_port(port) &&
     (ch == '\0' || ch == 's' || ch == 'r' || ch == ',');
 }
 
 static int set_ports_option(struct mg_context *ctx) {
   const char *list = ctx->config[LISTENING_PORTS];
   int on = 1, success = 1;
 #if defined(USE_IPV6)
   int off = 0;
 #endif
   struct vec vec;
   struct socket so, *ptr;
 
   while (success && (list = next_option(list, &vec, NULL)) != NULL) {
     if (!parse_port_string(&vec, &so)) {
       cry(fc(ctx), "%s: %.*s: invalid port spec. Expecting list of: %s",
           __func__, (int) vec.len, vec.ptr, "[IP_ADDRESS:]PORT[s|r]");
       success = 0;
     } else if (so.is_ssl && ctx->ssl_ctx == NULL) {
       cry(fc(ctx), "Cannot add SSL socket, is -ssl_certificate option set?");
       success = 0;
     } else if ((so.sock = socket(so.lsa.sa.sa_family, SOCK_STREAM, 6)) ==
                INVALID_SOCKET ||
                // On Windows, SO_REUSEADDR is recommended only for
                // broadcast UDP sockets
                setsockopt(so.sock, SOL_SOCKET, SO_REUSEADDR,
                           (void *) &on, sizeof(on)) != 0 ||
 #if defined(USE_IPV6)
                (so.lsa.sa.sa_family == AF_INET6 &&
                 setsockopt(so.sock, IPPROTO_IPV6, IPV6_V6ONLY, (void *) &off,
                            sizeof(off)) != 0) ||
 #endif
                bind(so.sock, &so.lsa.sa, so.lsa.sa.sa_family == AF_INET ?
                     sizeof(so.lsa.sin) : sizeof(so.lsa)) != 0 ||
                listen(so.sock, SOMAXCONN) != 0) {
       cry(fc(ctx), "%s: cannot bind to %.*s: %d (%s)", __func__,
           (int) vec.len, vec.ptr, ERRNO, strerror(errno));
       closesocket(so.sock);
       success = 0;
     } else if ((ptr = (struct socket *) realloc(ctx->listening_sockets,
                               (ctx->num_listening_sockets + 1) *
                               sizeof(ctx->listening_sockets[0]))) == NULL) {
       closesocket(so.sock);
       success = 0;
     } else {
       set_close_on_exec(so.sock);
       ctx->listening_sockets = ptr;
       ctx->listening_sockets[ctx->num_listening_sockets] = so;
       ctx->num_listening_sockets++;
     }
   }
 
   if (!success) {
     close_all_listening_sockets(ctx);
   }
 
   return success;
 }
 
 static void log_header(const struct mg_connection *conn, const char *header,
                        FILE *fp) {
   const char *header_value;
 
   if ((header_value = mg_get_header(conn, header)) == NULL) {
     (void) fprintf(fp, "%s", " -");
   } else {
     (void) fprintf(fp, " \"%s\"", header_value);
   }
 }
 
 static void log_access(const struct mg_connection *conn) {
   const struct mg_request_info *ri;
   FILE *fp;
   char date[64], src_addr[IP_ADDR_STR_LEN];
 
   fp = conn->ctx->config[ACCESS_LOG_FILE] == NULL ?  NULL :
     fopen(conn->ctx->config[ACCESS_LOG_FILE], "a+");
 
   if (fp == NULL)
     return;
 
   strftime(date, sizeof(date), "%d/%b/%Y:%H:%M:%S %z",
            localtime(&conn->birth_time));
 
   ri = &conn->request_info;
   flockfile(fp);
 
   sockaddr_to_string(src_addr, sizeof(src_addr), &conn->client.rsa);
   fprintf(fp, "%s - %s [%s] \"%s %s HTTP/%s\" %d %" INT64_FMT,
           src_addr, ri->remote_user == NULL ? "-" : ri->remote_user, date,
           ri->request_method ? ri->request_method : "-",
           ri->uri ? ri->uri : "-", ri->http_version,
           conn->status_code, conn->num_bytes_sent);
   log_header(conn, "Referer", fp);
   log_header(conn, "User-Agent", fp);
   fputc('\n', fp);
   fflush(fp);
 
   funlockfile(fp);
   fclose(fp);
 }
 
 // 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 *ctx, uint32_t remote_ip) {
   int allowed, flag;
   uint32_t net, mask;
   struct vec vec;
   const char *list = ctx->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];
     if ((flag != '+' && flag != '-') ||
         parse_net(&vec.ptr[1], &net, &mask) == 0) {
       cry(fc(ctx), "%s: subnet must be [+|-]x.x.x.x[/x]", __func__);
       return -1;
     }
 
     if (net == (remote_ip & mask)) {
       allowed = flag;
     }
   }
 
   return allowed == '+';
 }
 
 #if !defined(_WIN32)
 static int set_uid_option(struct mg_context *ctx) {
   struct passwd *pw;
   const char *uid = ctx->config[RUN_AS_USER];
   int success = 0;
 
   if (uid == NULL) {
     success = 1;
   } else {
     if ((pw = getpwnam(uid)) == NULL) {
       cry(fc(ctx), "%s: unknown user [%s]", __func__, uid);
     } else if (setgid(pw->pw_gid) == -1) {
       cry(fc(ctx), "%s: setgid(%s): %s", __func__, uid, strerror(errno));
     } else if (setuid(pw->pw_uid) == -1) {
       cry(fc(ctx), "%s: setuid(%s): %s", __func__, uid, strerror(errno));
     } else {
       success = 1;
     }
   }
 
   return success;
 }
 #endif // !_WIN32
 
 #if !defined(NO_SSL)
 static pthread_mutex_t *ssl_mutexes;
 
 static int sslize(struct mg_connection *conn, SSL_CTX *s, int (*func)(SSL *)) {
   return (conn->ssl = SSL_new(s)) != NULL &&
     SSL_set_fd(conn->ssl, conn->client.sock) == 1 &&
     func(conn->ssl) == 1;
 }
 
 // Return OpenSSL error message
 static const char *ssl_error(void) {
   unsigned long err;
   err = ERR_get_error();
   return err == 0 ? "" : ERR_error_string(err, NULL);
 }
 
 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]);
   }
 }
 
 static unsigned long ssl_id_callback(void) {
   return (unsigned long) pthread_self();
 }
 
 #if !defined(NO_SSL_DL)
 static int load_dll(struct mg_context *ctx, const char *dll_name,
                     struct ssl_func *sw) {
   union {void *p; void (*fp)(void);} u;
   void  *dll_handle;
   struct ssl_func *fp;
 
   if ((dll_handle = dlopen(dll_name, RTLD_LAZY)) == NULL) {
     cry(fc(ctx), "%s: cannot load %s", __func__, dll_name);
     return 0;
   }
 
   for (fp = sw; fp->name != NULL; fp++) {
 #ifdef _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
     if (u.fp == NULL) {
       cry(fc(ctx), "%s: %s: cannot find %s", __func__, dll_name, fp->name);
       return 0;
     } else {
       fp->ptr = u.fp;
     }
   }
 
   return 1;
 }
 #endif // NO_SSL_DL
 
 // Dynamically load SSL library. Set up ctx->ssl_ctx pointer.
 static int set_ssl_option(struct mg_context *ctx) {
   int i, size;
   const char *pem;
 
   // If PEM file is not specified and the init_ssl callback
   // is not specified, skip SSL initialization.
   if ((pem = ctx->config[SSL_CERTIFICATE]) == NULL &&
       ctx->callbacks.init_ssl == NULL) {
     return 1;
   }
 
 #if !defined(NO_SSL_DL)
   if (!load_dll(ctx, SSL_LIB, ssl_sw) ||
       !load_dll(ctx, CRYPTO_LIB, crypto_sw)) {
     return 0;
   }
 #endif // NO_SSL_DL
 
   // Initialize SSL library
   SSL_library_init();
   SSL_load_error_strings();
 
   if ((ctx->ssl_ctx = SSL_CTX_new(SSLv23_server_method())) == NULL) {
     cry(fc(ctx), "SSL_CTX_new (server) error: %s", ssl_error());
     return 0;
   }
 
   // If user callback returned non-NULL, that means that user callback has
   // set up certificate itself. In this case, skip sertificate setting.
   if ((ctx->callbacks.init_ssl == NULL ||
        !ctx->callbacks.init_ssl(ctx->ssl_ctx, ctx->user_data)) &&
       (SSL_CTX_use_certificate_file(ctx->ssl_ctx, pem, 1) == 0 ||
        SSL_CTX_use_PrivateKey_file(ctx->ssl_ctx, pem, 1) == 0)) {
     cry(fc(ctx), "%s: cannot open %s: %s", __func__, pem, ssl_error());
     return 0;
   }
 
   if (pem != NULL) {
     (void) SSL_CTX_use_certificate_chain_file(ctx->ssl_ctx, pem);
   }
 
   // Initialize locking callbacks, needed for thread safety.
   // http://www.openssl.org/support/faq.html#PROG1
   size = sizeof(pthread_mutex_t) * CRYPTO_num_locks();
   if ((ssl_mutexes = (pthread_mutex_t *) malloc((size_t)size)) == NULL) {
     cry(fc(ctx), "%s: cannot allocate mutexes: %s", __func__, ssl_error());
     return 0;
   }
 
   for (i = 0; i < CRYPTO_num_locks(); i++) {
     pthread_mutex_init(&ssl_mutexes[i], NULL);
   }
 
   CRYPTO_set_locking_callback(&ssl_locking_callback);
   CRYPTO_set_id_callback(&ssl_id_callback);
 
   return 1;
 }
 
 static void uninitialize_ssl(struct mg_context *ctx) {
   int i;
   if (ctx->ssl_ctx != NULL) {
     CRYPTO_set_locking_callback(NULL);
     for (i = 0; i < CRYPTO_num_locks(); i++) {
       pthread_mutex_destroy(&ssl_mutexes[i]);
     }
     CRYPTO_set_locking_callback(NULL);
     CRYPTO_set_id_callback(NULL);
   }
 }
 #endif // !NO_SSL
 
 static int set_gpass_option(struct mg_context *ctx) {
   struct file file = STRUCT_FILE_INITIALIZER;
   const char *path = ctx->config[GLOBAL_PASSWORDS_FILE];
   if (path != NULL && !mg_stat(fc(ctx), path, &file)) {
     cry(fc(ctx), "Cannot open %s: %s", path, strerror(ERRNO));
     return 0;
   }
   return 1;
 }
 
 static int set_acl_option(struct mg_context *ctx) {
   return check_acl(ctx, (uint32_t) 0x7f000001UL) != -1;
 }
 
 static void reset_per_request_attributes(struct mg_connection *conn) {
   conn->path_info = NULL;
   conn->num_bytes_sent = conn->consumed_content = 0;
   conn->status_code = -1;
   conn->must_close = conn->request_len = conn->throttle = 0;
 }
 
 static void close_socket_gracefully(struct mg_connection *conn) {
 #if defined(_WIN32)
   char buf[MG_BUF_LEN];
   int n;
 #endif
   struct linger linger;
 
   // Set linger option to avoid socket hanging out after close. This prevent
   // ephemeral port exhaust problem under high QPS.
   linger.l_onoff = 1;
   linger.l_linger = 1;
   setsockopt(conn->client.sock, SOL_SOCKET, SO_LINGER,
              (char *) &linger, sizeof(linger));
 
   // Send FIN to the client
   shutdown(conn->client.sock, SHUT_WR);
   set_non_blocking_mode(conn->client.sock);
 
 #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(NULL, conn, buf, sizeof(buf));
   } while (n > 0);
 #endif
 
   // Now we know that our FIN is ACK-ed, safe to close
   closesocket(conn->client.sock);
 }
 
 static void close_connection(struct mg_connection *conn) {
   conn->must_close = 1;
 
 #ifndef NO_SSL
   if (conn->ssl != NULL) {
     // Run SSL_shutdown twice to ensure completly close SSL connection
     SSL_shutdown(conn->ssl);
     SSL_free(conn->ssl);
     conn->ssl = NULL;
   }
 #endif
   if (conn->client.sock != INVALID_SOCKET) {
     close_socket_gracefully(conn);
     conn->client.sock = INVALID_SOCKET;
   }
 }
 
 void mg_close_connection(struct mg_connection *conn) {
 #ifndef NO_SSL
   if (conn->client_ssl_ctx != NULL) {
     SSL_CTX_free((SSL_CTX *) conn->client_ssl_ctx);
   }
 #endif
   close_connection(conn);
   free(conn);
 }
 
 static struct mg_connection *mg_connect(const char *host, int port, int use_ssl,
                                         char *ebuf, size_t ebuf_len) {
   static struct mg_context fake_ctx;
   struct mg_connection *conn = NULL;
   SOCKET sock;
 
   if ((sock = conn2(host, port, use_ssl, ebuf, ebuf_len)) == INVALID_SOCKET) {
   } else if ((conn = (struct mg_connection *)
               calloc(1, sizeof(*conn) + MAX_REQUEST_SIZE)) == NULL) {
     snprintf(ebuf, ebuf_len, "calloc(): %s", strerror(ERRNO));
     closesocket(sock);
 #ifndef NO_SSL
   } else if (use_ssl && (conn->client_ssl_ctx =
                          SSL_CTX_new(SSLv23_client_method())) == NULL) {
     snprintf(ebuf, ebuf_len, "SSL_CTX_new error");
     closesocket(sock);
     free(conn);
     conn = NULL;
 #endif // NO_SSL
   } else {
     socklen_t len = sizeof(struct sockaddr);
     conn->buf_size = MAX_REQUEST_SIZE;
     conn->buf = (char *) (conn + 1);
     conn->ctx = &fake_ctx;
     conn->client.sock = sock;
     getsockname(sock, &conn->client.rsa.sa, &len);
     conn->client.is_ssl = use_ssl;
 #ifndef NO_SSL
     if (use_ssl) {
       // SSL_CTX_set_verify call is needed to switch off server certificate
       // checking, which is off by default in OpenSSL and on in yaSSL.
       SSL_CTX_set_verify(conn->client_ssl_ctx, 0, 0);
       sslize(conn, conn->client_ssl_ctx, SSL_connect);
     }
 #endif
   }
 
   return conn;
 }
 
 static int is_valid_uri(const char *uri) {
   // Conform to http://www.w3.org/Protocols/rfc2616/rfc2616-sec5.html#sec5.1.2
   // URI can be an asterisk (*) or should start with slash.
   return uri[0] == '/' || (uri[0] == '*' && uri[1] == '\0');
 }
 
 static int getreq(struct mg_connection *conn, char *ebuf, size_t ebuf_len) {
   const char *cl;
 
   ebuf[0] = '\0';
   reset_per_request_attributes(conn);
   conn->request_len = read_request(NULL, conn, conn->buf, conn->buf_size,
                                    &conn->data_len);
   assert(conn->request_len < 0 || conn->data_len >= conn->request_len);
 
   if (conn->request_len == 0 && conn->data_len == conn->buf_size) {
     snprintf(ebuf, ebuf_len, "%s", "Request Too Large");
   } else if (conn->request_len <= 0) {
     snprintf(ebuf, ebuf_len, "%s", "Client closed connection");
   } else if (parse_http_message(conn->buf, conn->buf_size,
                                 &conn->request_info) <= 0) {
     snprintf(ebuf, ebuf_len, "Bad request: [%.*s]", conn->data_len, conn->buf);
   } else {
     // Request is valid
     if ((cl = get_header(&conn->request_info, "Content-Length")) != NULL) {
       conn->content_len = strtoll(cl, NULL, 10);
     } else if (!mg_strcasecmp(conn->request_info.request_method, "POST") ||
                !mg_strcasecmp(conn->request_info.request_method, "PUT")) {
       conn->content_len = -1;
     } else {
       conn->content_len = 0;
     }
     conn->birth_time = time(NULL);
   }
   return ebuf[0] == '\0';
 }
 
 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;
 
   va_start(ap, fmt);
   ebuf[0] = '\0';
   if ((conn = mg_connect(host, port, use_ssl, ebuf, ebuf_len)) == NULL) {
   } else if (mg_vprintf(conn, fmt, ap) <= 0) {
     snprintf(ebuf, ebuf_len, "%s", "Error sending request");
   } else {
     getreq(conn, ebuf, ebuf_len);
   }
   if (ebuf[0] != '\0' && conn != NULL) {
     mg_close_connection(conn);
     conn = NULL;
   }
 
   return conn;
 }
 
 static void process_new_connection(struct mg_connection *conn) {
   struct mg_request_info *ri = &conn->request_info;
   int keep_alive_enabled, keep_alive, discard_len;
   char ebuf[100];
 
   keep_alive_enabled = !strcmp(conn->ctx->config[ENABLE_KEEP_ALIVE], "yes");
   keep_alive = 0;
 
   // Important: on new connection, reset the receiving buffer. Credit goes
   // to crule42.
   conn->data_len = 0;
   do {
     if (!getreq(conn, ebuf, sizeof(ebuf))) {
       send_http_error(conn, 500, "Server Error", "%s", ebuf);
       conn->must_close = 1;
     } else if (!is_valid_uri(conn->request_info.uri)) {
       snprintf(ebuf, sizeof(ebuf), "Invalid URI: [%s]", ri->uri);
       send_http_error(conn, 400, "Bad Request", "%s", ebuf);
     } else if (strcmp(ri->http_version, "1.0") &&
                strcmp(ri->http_version, "1.1")) {
       snprintf(ebuf, sizeof(ebuf), "Bad HTTP version: [%s]", ri->http_version);
       send_http_error(conn, 505, "Bad HTTP version", "%s", ebuf);
     }
 
     if (ebuf[0] == '\0') {
       handle_request(conn);
       if (conn->ctx->callbacks.end_request != NULL) {
         conn->ctx->callbacks.end_request(conn, conn->status_code);
       }
       log_access(conn);
     }
     if (ri->remote_user != NULL) {
       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.
     keep_alive = conn->ctx->stop_flag == 0 && keep_alive_enabled &&
       conn->content_len >= 0 && should_keep_alive(conn);
 
     // Discard all buffered data for this request
     discard_len = conn->content_len >= 0 && conn->request_len > 0 &&
       conn->request_len + conn->content_len < (int64_t) conn->data_len ?
       (int) (conn->request_len + conn->content_len) : conn->data_len;
     assert(discard_len >= 0);
     memmove(conn->buf, conn->buf + discard_len, conn->data_len - discard_len);
     conn->data_len -= discard_len;
     assert(conn->data_len >= 0);
     assert(conn->data_len <= conn->buf_size);
   } while (keep_alive);
 }
 
 // Worker threads take accepted socket from the queue
 static int consume_socket(struct mg_context *ctx, struct socket *sp) {
   (void) pthread_mutex_lock(&ctx->mutex);
   DEBUG_TRACE(("going idle"));
 
   // If the queue is empty, wait. We're idle at this point.
   while (ctx->sq_head == ctx->sq_tail && ctx->stop_flag == 0) {
     pthread_cond_wait(&ctx->sq_full, &ctx->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->queue[ctx->sq_tail % ARRAY_SIZE(ctx->queue)];
     ctx->sq_tail++;
     DEBUG_TRACE(("grabbed socket %d, going busy", sp->sock));
 
     // Wrap pointers if needed
     while (ctx->sq_tail > (int) ARRAY_SIZE(ctx->queue)) {
       ctx->sq_tail -= ARRAY_SIZE(ctx->queue);
       ctx->sq_head -= ARRAY_SIZE(ctx->queue);
     }
   }
 
   (void) pthread_cond_signal(&ctx->sq_empty);
   (void) pthread_mutex_unlock(&ctx->mutex);
 
   return !ctx->stop_flag;
 }
 
 static void *worker_thread(void *thread_func_param) {
   struct mg_context *ctx = (struct mg_context *) thread_func_param;
   struct mg_connection *conn;
 
   conn = (struct mg_connection *) calloc(1, sizeof(*conn) + MAX_REQUEST_SIZE);
   if (conn == NULL) {
     cry(fc(ctx), "%s", "Cannot create new connection struct, OOM");
   } else {
     conn->buf_size = MAX_REQUEST_SIZE;
     conn->buf = (char *) (conn + 1);
     conn->ctx = ctx;
     conn->request_info.user_data = ctx->user_data;
 
     // 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)) {
       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.
       // TODO(lsm): Fix IPv6 case
       conn->request_info.remote_port = ntohs(conn->client.rsa.sin.sin_port);
       memcpy(&conn->request_info.remote_ip,
              &conn->client.rsa.sin.sin_addr.s_addr, 4);
       conn->request_info.remote_ip = ntohl(conn->request_info.remote_ip);
       conn->request_info.is_ssl = conn->client.is_ssl;
 
       if (!conn->client.is_ssl
 #ifndef NO_SSL
           || sslize(conn, conn->ctx->ssl_ctx, SSL_accept)
 #endif
          ) {
         process_new_connection(conn);
       }
 
       close_connection(conn);
     }
     free(conn);
   }
 
   // Signal master that we're done with connection and exiting
   (void) pthread_mutex_lock(&ctx->mutex);
   ctx->num_threads--;
   (void) pthread_cond_signal(&ctx->cond);
   assert(ctx->num_threads >= 0);
   (void) pthread_mutex_unlock(&ctx->mutex);
 
   DEBUG_TRACE(("exiting"));
   return NULL;
 }
 
 // Master thread adds accepted socket to a queue
 static void produce_socket(struct mg_context *ctx, const struct socket *sp) {
   (void) pthread_mutex_lock(&ctx->mutex);
 
   // If the queue is full, wait
   while (ctx->stop_flag == 0 &&
          ctx->sq_head - ctx->sq_tail >= (int) ARRAY_SIZE(ctx->queue)) {
     (void) pthread_cond_wait(&ctx->sq_empty, &ctx->mutex);
   }
 
   if (ctx->sq_head - ctx->sq_tail < (int) ARRAY_SIZE(ctx->queue)) {
     // Copy socket to the queue and increment head
     ctx->queue[ctx->sq_head % ARRAY_SIZE(ctx->queue)] = *sp;
     ctx->sq_head++;
     DEBUG_TRACE(("queued socket %d", sp->sock));
   }
 
   (void) pthread_cond_signal(&ctx->sq_full);
   (void) pthread_mutex_unlock(&ctx->mutex);
 }
 
 static int set_sock_timeout(SOCKET sock, int milliseconds) {
 #ifdef _WIN32
   DWORD t = milliseconds;
 #else
   struct timeval t;
   t.tv_sec = milliseconds / 1000;
   t.tv_usec = (milliseconds * 1000) % 1000000;
 #endif
   return setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (void *) &t, sizeof(t)) ||
     setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (void *) &t, sizeof(t));
 }
 
 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);
   int on = 1;
 
   if ((so.sock = accept(listener->sock, &so.rsa.sa, &len)) == INVALID_SOCKET) {
   } else if (!check_acl(ctx, ntohl(* (uint32_t *) &so.rsa.sin.sin_addr))) {
     sockaddr_to_string(src_addr, sizeof(src_addr), &so.rsa);
     cry(fc(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);
     so.is_ssl = listener->is_ssl;
     so.ssl_redir = listener->ssl_redir;
     getsockname(so.sock, &so.lsa.sa, &len);
     // Set TCP keep-alive. 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.
     setsockopt(so.sock, SOL_SOCKET, SO_KEEPALIVE, (void *) &on, sizeof(on));
     set_sock_timeout(so.sock, atoi(ctx->config[REQUEST_TIMEOUT]));
     produce_socket(ctx, &so);
   }
 }
 
 static void *master_thread(void *thread_func_param) {
   struct mg_context *ctx = (struct mg_context *) thread_func_param;
   struct pollfd *pfd;
   int i;
 
   // Increase priority of the master thread
 #if defined(_WIN32)
   SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_ABOVE_NORMAL);
 #endif
 
 #if defined(ISSUE_317)
   struct sched_param sched_param;
   sched_param.sched_priority = sched_get_priority_max(SCHED_RR);
   pthread_setschedparam(pthread_self(), SCHED_RR, &sched_param);
 #endif
 
   pfd = (struct pollfd *) calloc(ctx->num_listening_sockets, sizeof(pfd[0]));
   while (pfd != NULL && ctx->stop_flag == 0) {
     for (i = 0; i < ctx->num_listening_sockets; i++) {
       pfd[i].fd = ctx->listening_sockets[i].sock;
       pfd[i].events = POLLIN;
     }
 
     if (poll(pfd, ctx->num_listening_sockets, 200) > 0) {
       for (i = 0; i < ctx->num_listening_sockets; i++) {
         // NOTE(lsm): on QNX, poll() returns POLLRDNORM after the
         // successfull poll, and POLLIN is defined as (POLLRDNORM | POLLRDBAND)
         // Therefore, we're checking pfd[i].revents & POLLIN, not
         // pfd[i].revents == POLLIN.
         if (ctx->stop_flag == 0 && (pfd[i].revents & POLLIN)) {
           accept_new_connection(&ctx->listening_sockets[i], ctx);
         }
       }
     }
 #if __rtems__
     else {
       struct timespec t = { .tv_sec = 0, .tv_nsec = 500000000L };
       nanosleep(&t, &t);
     }
 #endif /* __rtems__ */
   }
   free(pfd);
   DEBUG_TRACE(("stopping workers"));
 
   // Stop signal received: somebody called mg_stop. Quit.
   close_all_listening_sockets(ctx);
 
   // Wakeup workers that are waiting for connections to handle.
   pthread_cond_broadcast(&ctx->sq_full);
 
   // Wait until all threads finish
   (void) pthread_mutex_lock(&ctx->mutex);
   while (ctx->num_threads > 0) {
     (void) pthread_cond_wait(&ctx->cond, &ctx->mutex);
   }
   (void) pthread_mutex_unlock(&ctx->mutex);
 
   // All threads exited, no sync is needed. Destroy mutex and condvars
   (void) pthread_mutex_destroy(&ctx->mutex);
   (void) pthread_cond_destroy(&ctx->cond);
   (void) pthread_cond_destroy(&ctx->sq_empty);
   (void) pthread_cond_destroy(&ctx->sq_full);
 
 #if !defined(NO_SSL)
   uninitialize_ssl(ctx);
 #endif
   DEBUG_TRACE(("exiting"));
 
   // 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.
   ctx->stop_flag = 2;
   return NULL;
 }
 
 static void free_context(struct mg_context *ctx) {
   int i;
 
   // Deallocate config parameters
   for (i = 0; i < NUM_OPTIONS; i++) {
     if (ctx->config[i] != NULL)
       free(ctx->config[i]);
   }
 
 #ifndef NO_SSL
   // Deallocate SSL context
   if (ctx->ssl_ctx != NULL) {
     SSL_CTX_free(ctx->ssl_ctx);
   }
   if (ssl_mutexes != NULL) {
     free(ssl_mutexes);
     ssl_mutexes = NULL;
   }
 #endif // !NO_SSL
 
   // Deallocate context itself
   free(ctx);
 }
 
 void mg_stop(struct mg_context *ctx) {
   ctx->stop_flag = 1;
 
   // Wait until mg_fini() stops
   while (ctx->stop_flag != 2) {
     (void) mg_sleep(10);
   }
   free_context(ctx);
 
 #if defined(_WIN32) && !defined(__SYMBIAN32__)
   (void) WSACleanup();
 #endif // _WIN32
 }
 
 struct mg_context *mg_start(const struct mg_callbacks *callbacks,
                             void *user_data,
                             const char **options) {
   struct mg_context *ctx;
   const char *name, *value, *default_value;
   int i;
 
 #if defined(_WIN32) && !defined(__SYMBIAN32__)
   WSADATA data;
   WSAStartup(MAKEWORD(2,2), &data);
   InitializeCriticalSection(&global_log_file_lock);
 #endif // _WIN32
 
   // Allocate context and initialize reasonable general case defaults.
   // TODO(lsm): do proper error handling here.
   if ((ctx = (struct mg_context *) calloc(1, sizeof(*ctx))) == NULL) {
     return NULL;
   }
   ctx->callbacks = *callbacks;
   ctx->user_data = user_data;
 
   while (options && (name = *options++) != NULL) {
     if ((i = get_option_index(name)) == -1) {
       cry(fc(ctx), "Invalid option: %s", name);
       free_context(ctx);
       return NULL;
     } else if ((value = *options++) == NULL) {
       cry(fc(ctx), "%s: option value cannot be NULL", name);
       free_context(ctx);
       return NULL;
     }
     if (ctx->config[i] != NULL) {
       cry(fc(ctx), "warning: %s: duplicate option", name);
       free(ctx->config[i]);
     }
     ctx->config[i] = mg_strdup(value);
     DEBUG_TRACE(("[%s] -> [%s]", name, value));
   }
 
   // Set default value if needed
   for (i = 0; config_options[i * 2] != NULL; i++) {
     default_value = config_options[i * 2 + 1];
     if (ctx->config[i] == NULL && default_value != NULL) {
       ctx->config[i] = mg_strdup(default_value);
     }
   }
 
   // NOTE(lsm): order is important here. SSL certificates must
   // be initialized before listening ports. UID must be set last.
   if (!set_gpass_option(ctx) ||
 #if !defined(NO_SSL)
       !set_ssl_option(ctx) ||
 #endif
       !set_ports_option(ctx) ||
 #if !defined(_WIN32)
       !set_uid_option(ctx) ||
 #endif
       !set_acl_option(ctx)) {
     free_context(ctx);
     return NULL;
   }
 
 #if !defined(_WIN32) && !defined(__SYMBIAN32__)
   // Ignore SIGPIPE signal, so if browser cancels the request, it
   // won't kill the whole process.
   (void) signal(SIGPIPE, SIG_IGN);
   // Also ignoring SIGCHLD to let the OS to reap zombies properly.
   (void) signal(SIGCHLD, SIG_IGN);
 #endif // !_WIN32
 
   (void) pthread_mutex_init(&ctx->mutex, NULL);
   (void) pthread_cond_init(&ctx->cond, NULL);
   (void) pthread_cond_init(&ctx->sq_empty, NULL);
   (void) pthread_cond_init(&ctx->sq_full, NULL);
 
   // Start master (listening) thread
   mg_start_thread(master_thread, ctx);
 
   // Start worker threads
   for (i = 0; i < atoi(ctx->config[NUM_THREADS]); i++) {
     if (mg_start_thread(worker_thread, ctx) != 0) {
       cry(fc(ctx), "Cannot start worker thread: %ld", (long) ERRNO);
     } else {
       ctx->num_threads++;
     }
   }
 
   return ctx;
 }
 #ifdef __rtems__
 #include <rtems/printer.h>
 
 static int mg_printer_plugin(void *context, const char *fmt, va_list ap) {
   return mg_vprintf(context, fmt, ap);
 }
 
 void rtems_print_printer_mg_printf(rtems_printer *printer, struct mg_connection *conn) {
   printer->context = conn;
   printer->printer = mg_printer_plugin;
 }
 #endif /* __rtems__ */