mongoose.c

        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


// 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 > (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;
}

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);
}

static int mg_chunked_printf(struct mg_connection *conn, const char *fmt, ...) {
  char mem[MG_BUF_LEN], *buf = mem;
  int len;

  va_list ap;
  va_start(ap, fmt);
  if ((len = alloc_vprintf(&buf, sizeof(mem), fmt, ap)) > 0) {
    len = mg_printf(conn, "%X\r\n%s\r\n", len, buf);
  }

  if (buf != mem && buf != NULL) {
    free(buf);
  }

  return len;
}



#if !defined(NO_SSL)
// 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.
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}
};

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) {
    //  MG_INIT_SSL
    //  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.
  // MG_INIT_SSL
  if (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 SOCKET conn2(const char *host, int port, int use_ssl,
                    char *ebuf, size_t ebuf_len) {
  struct sockaddr_in sin;
  struct hostent *he = NULL;
  SOCKET sock = INVALID_SOCKET;

  (void) use_ssl; // Prevent warning for -DNO_SSL case

  if (host == NULL) {
    snprintf(ebuf, ebuf_len, "%s", "NULL host");
#ifndef NO_SSL
  } 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()
#endif
  } 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;
}

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;
}

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 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, "application/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 void print_dir_entry(const struct de *de) {
  char size[64], mod[64], href[PATH_MAX * 3];
  const char *slash = de->file.is_directory ? "/" : "";

  if (de->file.is_directory) {
    mg_snprintf(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(size, sizeof(size), "%d", (int) de->file.size);
    } else if (de->file.size < 0x100000) {
      mg_snprintf(size, sizeof(size),
                  "%.1fk", (double) de->file.size / 1024.0);
    } else if (de->file.size < 0x40000000) {
      mg_snprintf(size, sizeof(size),
                  "%.1fM", (double) de->file.size / 1048576);
    } else {
      mg_snprintf(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_chunked_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, slash, de->file_name, slash, 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(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(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
      if (!strcmp(dp->d_name, ".") ||
          !strcmp(dp->d_name, "..")) {
        continue;
      }

      mg_snprintf(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(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"
            "Transfer-Encoding: Chunked\r\n"
            "Content-Type: text/html; charset=utf-8\r\n\r\n");

  conn->num_bytes_sent += mg_chunked_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_chunked_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_chunked_printf(conn, "%s",
                                            "</table></body></html>");
  conn->num_bytes_sent += mg_write(conn, "0\r\n\r\n", 5);
  conn->status_code = 200;
}

// 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(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(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 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);
}

// 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;
}

static int parse_range_header(const char *header, int64_t *a, int64_t *b) {
  return sscanf(header, "bytes=%" INT64_FMT "-%" INT64_FMT, a, b);
}

// Return number of bytes left to read for this connection
static int64_t left_to_read(const struct mg_connection *conn) {
  return conn->content_len + conn->request_len - conn->num_bytes_read;
}

// 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);

#if !defined(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 (len <= 0) return 0;
  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);
  }
  if (nread > 0) {
    conn->num_bytes_read += nread;
  }

  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 {
      nread += n;
      len -= n;
    }
  }

  return nread;
}

int mg_read(struct mg_connection *conn, void *buf, int len) {
  int n, buffered_len, nread = 0;
  int64_t left;

  if (conn->content_len <= 0) {
    return 0;
  }

  // conn->buf           body
  //    |=================|==========|===============|
  //    |<--request_len-->|                          |
  //    |<-----------data_len------->|      conn->buf + conn->buf_size

  // First, check for data buffered in conn->buf by read_request().
  if (len > 0 && (buffered_len = conn->data_len - conn->request_len) > 0) {
    char *body = conn->buf + conn->request_len;
    if (buffered_len > len) buffered_len = len;
    if (buffered_len > conn->content_len) buffered_len = (int)conn->content_len;

    memcpy(buf, body, (size_t) buffered_len);
    memmove(body, body + buffered_len,
            &conn->buf[conn->data_len] - &body[buffered_len]);
    len -= buffered_len;
    conn->data_len -= buffered_len;
    nread += buffered_len;
  }

  // Read data from the socket.
  if (len > 0 && (left = left_to_read(conn)) > 0) {
    if (left < len) {
      len = (int) left;
    }
    n = pull_all(NULL, conn, (char *) buf + nread, (int) len);
    nread = n >= 0 ? nread + n : n;
  }

  return nread;
}

int mg_write(struct mg_connection *conn, const void *buf, int len) {
  return (int) push(NULL, conn->client.sock, conn->ssl, (const char *) buf,
                    (int64_t) len);
}

// 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;
}

// Send len bytes from the opened file to the client.
static void send_file_data(struct mg_connection *conn, FILE *fp,
                           int64_t offset, int64_t len) {
  char buf[MG_BUF_LEN];
  int num_read, num_written, to_read;

  // If offset is beyond file boundaries, don't send anything
  if (offset > 0 && fseeko(fp, offset, SEEK_SET) != 0) {
    return;
  }

  while (len > 0) {
    // Calculate how much to read from the file in the buffer
    to_read = sizeof(buf);
    if ((int64_t) to_read > len) {