mongoose.c

  // 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);
      call_user(MG_REQUEST_END, conn, (void *) 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->event.user_data = ctx->user_data;

    call_user(MG_THREAD_BEGIN, conn, NULL);

    // 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);
    }
    call_user(MG_THREAD_END, conn, NULL);
    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

  call_user(MG_THREAD_BEGIN, fc(ctx), NULL);

  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);
        }
      }
    }
  }
  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"));

  call_user(MG_THREAD_END, fc(ctx), NULL);

  // Signal mg_stop() that we're done.
  // WARNING: This must be the very last thing this
  // thread does, as ctx becomes invalid after this line.
  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 char **options,
                            mg_event_handler_t func,
                            void *user_data) {
  struct mg_context *ctx;
  const char *name, *value, *default_value;
  int i;

#if defined(_WIN32) && !defined(__SYMBIAN32__)
  WSADATA data;
  WSAStartup(MAKEWORD(2,2), &data);
#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->event_handler = func;
  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);
#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;
}