660 lines
18 KiB
C
660 lines
18 KiB
C
/*
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* Copyright (C) 2013 Glyptodon LLC
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "config.h"
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#include "client.h"
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#include "log.h"
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <libgen.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <guacamole/client.h>
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#include <guacamole/error.h>
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#include <guacamole/instruction.h>
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#include <guacamole/plugin.h>
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#include <guacamole/protocol.h>
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#ifdef ENABLE_SSL
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#include <openssl/ssl.h>
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#include "socket-ssl.h"
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#endif
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#define GUACD_DEV_NULL "/dev/null"
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#define GUACD_ROOT "/"
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void guacd_handle_connection(guac_socket* socket) {
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guac_client* client;
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guac_client_plugin* plugin;
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guac_instruction* select;
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guac_instruction* size;
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guac_instruction* audio;
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guac_instruction* video;
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guac_instruction* connect;
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int init_result;
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/* Reset guac_error */
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guac_error = GUAC_STATUS_SUCCESS;
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guac_error_message = NULL;
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/* Get protocol from select instruction */
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select = guac_instruction_expect(
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socket, GUACD_USEC_TIMEOUT, "select");
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if (select == NULL) {
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/* Log error */
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guacd_log_guac_error("Error reading \"select\"");
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/* Free resources */
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guac_socket_free(socket);
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return;
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}
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/* Validate args to select */
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if (select->argc != 1) {
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/* Log error */
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guacd_log_error("Bad number of arguments to \"select\" (%i)",
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select->argc);
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/* Free resources */
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guac_socket_free(socket);
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return;
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}
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guacd_log_info("Protocol \"%s\" selected", select->argv[0]);
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/* Get plugin from protocol in select */
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plugin = guac_client_plugin_open(select->argv[0]);
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guac_instruction_free(select);
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if (plugin == NULL) {
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/* Log error */
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guacd_log_guac_error("Error loading client plugin");
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/* Free resources */
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guac_socket_free(socket);
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return;
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}
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/* Send args response */
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if (guac_protocol_send_args(socket, plugin->args)
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|| guac_socket_flush(socket)) {
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/* Log error */
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guacd_log_guac_error("Error sending \"args\"");
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if (guac_client_plugin_close(plugin))
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guacd_log_guac_error("Error closing client plugin");
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guac_socket_free(socket);
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return;
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}
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/* Get optimal screen size */
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size = guac_instruction_expect(
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socket, GUACD_USEC_TIMEOUT, "size");
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if (size == NULL) {
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/* Log error */
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guacd_log_guac_error("Error reading \"size\"");
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/* Free resources */
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guac_socket_free(socket);
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return;
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}
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/* Get supported audio formats */
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audio = guac_instruction_expect(
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socket, GUACD_USEC_TIMEOUT, "audio");
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if (audio == NULL) {
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/* Log error */
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guacd_log_guac_error("Error reading \"audio\"");
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/* Free resources */
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guac_socket_free(socket);
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return;
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}
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/* Get supported video formats */
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video = guac_instruction_expect(
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socket, GUACD_USEC_TIMEOUT, "video");
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if (video == NULL) {
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/* Log error */
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guacd_log_guac_error("Error reading \"video\"");
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/* Free resources */
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guac_socket_free(socket);
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return;
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}
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/* Get args from connect instruction */
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connect = guac_instruction_expect(
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socket, GUACD_USEC_TIMEOUT, "connect");
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if (connect == NULL) {
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/* Log error */
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guacd_log_guac_error("Error reading \"connect\"");
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if (guac_client_plugin_close(plugin))
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guacd_log_guac_error("Error closing client plugin");
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guac_socket_free(socket);
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return;
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}
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/* Get client */
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client = guac_client_alloc();
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client->socket = socket;
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client->log_info_handler = guacd_client_log_info;
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client->log_error_handler = guacd_client_log_error;
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/* Parse optimal screen dimensions from size instruction */
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client->info.optimal_width = atoi(size->argv[0]);
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client->info.optimal_height = atoi(size->argv[1]);
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/* If DPI given, set the client resolution */
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if (size->argc >= 3)
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client->info.optimal_resolution = atoi(size->argv[2]);
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/* Otherwise, use a safe default for rough backwards compatibility */
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else
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client->info.optimal_resolution = 96;
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/* Store audio mimetypes */
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client->info.audio_mimetypes = malloc(sizeof(char*) * (audio->argc+1));
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memcpy(client->info.audio_mimetypes, audio->argv,
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sizeof(char*) * audio->argc);
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client->info.audio_mimetypes[audio->argc] = NULL;
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/* Store video mimetypes */
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client->info.video_mimetypes = malloc(sizeof(char*) * (video->argc+1));
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memcpy(client->info.video_mimetypes, video->argv,
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sizeof(char*) * video->argc);
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client->info.video_mimetypes[video->argc] = NULL;
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/* Init client */
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init_result = guac_client_plugin_init_client(plugin,
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client, connect->argc, connect->argv);
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guac_instruction_free(connect);
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/* If client could not be started, free everything and fail */
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if (init_result) {
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guac_client_free(client);
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guacd_log_guac_error("Error instantiating client");
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if (guac_client_plugin_close(plugin))
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guacd_log_guac_error("Error closing client plugin");
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guac_socket_free(socket);
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return;
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}
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/* Start client threads */
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guacd_log_info("Starting client");
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if (guacd_client_start(client))
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guacd_log_error("Client finished abnormally");
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else
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guacd_log_info("Client finished normally");
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/* Free mimetype lists */
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free(client->info.audio_mimetypes);
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free(client->info.video_mimetypes);
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/* Free remaining instructions */
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guac_instruction_free(audio);
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guac_instruction_free(video);
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guac_instruction_free(size);
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/* Clean up */
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guac_client_free(client);
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if (guac_client_plugin_close(plugin))
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guacd_log_error("Error closing client plugin");
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/* Close socket */
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guac_socket_free(socket);
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}
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int redirect_fd(int fd, int flags) {
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/* Attempt to open bit bucket */
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int new_fd = open(GUACD_DEV_NULL, flags);
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if (new_fd < 0)
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return 1;
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/* If descriptor is different, redirect old to new and close new */
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if (new_fd != fd) {
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dup2(new_fd, fd);
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close(new_fd);
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}
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return 0;
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}
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int daemonize() {
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pid_t pid;
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/* Fork once to ensure we aren't the process group leader */
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pid = fork();
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if (pid < 0) {
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guacd_log_error("Could not fork() parent: %s", strerror(errno));
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return 1;
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}
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/* Exit if we are the parent */
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if (pid > 0) {
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guacd_log_info("Exiting and passing control to PID %i", pid);
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_exit(0);
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}
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/* Start a new session (if not already group leader) */
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setsid();
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/* Fork again so the session group leader exits */
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pid = fork();
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if (pid < 0) {
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guacd_log_error("Could not fork() group leader: %s", strerror(errno));
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return 1;
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}
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/* Exit if we are the parent */
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if (pid > 0) {
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guacd_log_info("Exiting and passing control to PID %i", pid);
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_exit(0);
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}
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/* Change to root directory */
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if (chdir(GUACD_ROOT) < 0) {
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guacd_log_error(
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"Unable to change working directory to "
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GUACD_ROOT);
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return 1;
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}
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/* Reopen the 3 stdxxx to /dev/null */
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if (redirect_fd(STDIN_FILENO, O_RDONLY)
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|| redirect_fd(STDOUT_FILENO, O_WRONLY)
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|| redirect_fd(STDERR_FILENO, O_WRONLY)) {
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guacd_log_error(
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"Unable to redirect standard file descriptors to "
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GUACD_DEV_NULL);
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return 1;
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}
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/* Success */
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return 0;
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}
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int main(int argc, char* argv[]) {
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/* Server */
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int socket_fd;
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struct addrinfo* addresses;
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struct addrinfo* current_address;
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char bound_address[1024];
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char bound_port[64];
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int opt_on = 1;
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struct addrinfo hints = {
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.ai_family = AF_UNSPEC,
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.ai_socktype = SOCK_STREAM,
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.ai_protocol = IPPROTO_TCP
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};
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/* Client */
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struct sockaddr_in client_addr;
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socklen_t client_addr_len;
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int connected_socket_fd;
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/* Arguments */
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char* listen_address = NULL; /* Default address of INADDR_ANY */
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char* listen_port = "4822"; /* Default port */
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char* pidfile = NULL;
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int opt;
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int foreground = 0;
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#ifdef ENABLE_SSL
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/* SSL */
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char* cert_file = NULL;
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char* key_file = NULL;
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SSL_CTX* ssl_context = NULL;
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#endif
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/* General */
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int retval;
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/* Parse arguments */
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while ((opt = getopt(argc, argv, "l:b:p:C:K:f")) != -1) {
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if (opt == 'l') {
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listen_port = strdup(optarg);
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}
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else if (opt == 'b') {
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listen_address = strdup(optarg);
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}
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else if (opt == 'f') {
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foreground = 1;
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}
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else if (opt == 'p') {
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pidfile = strdup(optarg);
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}
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#ifdef ENABLE_SSL
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else if (opt == 'C') {
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cert_file = strdup(optarg);
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}
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else if (opt == 'K') {
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key_file = strdup(optarg);
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}
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#else
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else if (opt == 'C' || opt == 'K') {
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fprintf(stderr,
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"This guacd does not have SSL/TLS support compiled in.\n\n"
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"If you wish to enable support for the -%c option, please install libssl and\n"
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"recompile guacd.\n",
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opt);
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exit(EXIT_FAILURE);
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}
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#endif
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else {
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fprintf(stderr, "USAGE: %s"
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" [-l LISTENPORT]"
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" [-b LISTENADDRESS]"
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" [-p PIDFILE]"
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#ifdef ENABLE_SSL
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" [-C CERTIFICATE_FILE]"
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" [-K PEM_FILE]"
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#endif
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" [-f]\n", argv[0]);
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exit(EXIT_FAILURE);
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}
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}
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/* Set up logging prefix */
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strncpy(log_prefix, basename(argv[0]), sizeof(log_prefix));
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/* Open log as early as we can */
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openlog(NULL, LOG_PID, LOG_DAEMON);
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/* Log start */
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guacd_log_info("Guacamole proxy daemon (guacd) version " VERSION);
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/* Get addresses for binding */
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if ((retval = getaddrinfo(listen_address, listen_port,
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&hints, &addresses))) {
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guacd_log_error("Error parsing given address or port: %s",
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gai_strerror(retval));
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exit(EXIT_FAILURE);
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}
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/* Get socket */
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socket_fd = socket(AF_INET, SOCK_STREAM, 0);
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if (socket_fd < 0) {
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guacd_log_error("Error opening socket: %s", strerror(errno));
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exit(EXIT_FAILURE);
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}
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/* Allow socket reuse */
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if (setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR,
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(void*) &opt_on, sizeof(opt_on))) {
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guacd_log_info("Unable to set socket options for reuse: %s",
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strerror(errno));
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}
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/* Attempt binding of each address until success */
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current_address = addresses;
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while (current_address != NULL) {
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int retval;
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/* Resolve hostname */
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if ((retval = getnameinfo(current_address->ai_addr,
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current_address->ai_addrlen,
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bound_address, sizeof(bound_address),
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bound_port, sizeof(bound_port),
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NI_NUMERICHOST | NI_NUMERICSERV)))
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guacd_log_error("Unable to resolve host: %s",
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gai_strerror(retval));
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/* Attempt to bind socket to address */
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if (bind(socket_fd,
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current_address->ai_addr,
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current_address->ai_addrlen) == 0) {
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guacd_log_info("Successfully bound socket to "
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"host %s, port %s", bound_address, bound_port);
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/* Done if successful bind */
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break;
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}
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/* Otherwise log information regarding bind failure */
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else
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guacd_log_info("Unable to bind socket to "
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"host %s, port %s: %s",
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bound_address, bound_port, strerror(errno));
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current_address = current_address->ai_next;
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}
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/* If unable to bind to anything, fail */
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if (current_address == NULL) {
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guacd_log_error("Unable to bind socket to any addresses.");
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exit(EXIT_FAILURE);
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}
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#ifdef ENABLE_SSL
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/* Init SSL if enabled */
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if (key_file != NULL || cert_file != NULL) {
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/* Init SSL */
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guacd_log_info("Communication will require SSL/TLS.");
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SSL_library_init();
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SSL_load_error_strings();
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ssl_context = SSL_CTX_new(SSLv23_server_method());
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/* Load key */
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if (key_file != NULL) {
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guacd_log_info("Using PEM keyfile %s", key_file);
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if (!SSL_CTX_use_PrivateKey_file(ssl_context, key_file, SSL_FILETYPE_PEM)) {
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guacd_log_error("Unable to load keyfile.");
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exit(EXIT_FAILURE);
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}
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}
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else
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guacd_log_info("No PEM keyfile given - SSL/TLS may not work.");
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/* Load cert file if specified */
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if (cert_file != NULL) {
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guacd_log_info("Using certificate file %s", cert_file);
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if (!SSL_CTX_use_certificate_chain_file(ssl_context, cert_file)) {
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guacd_log_error("Unable to load certificate.");
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exit(EXIT_FAILURE);
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}
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}
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else
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guacd_log_info("No certificate file given - SSL/TLS may not work.");
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}
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#endif
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/* Daemonize if requested */
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if (!foreground) {
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/* Attempt to daemonize process */
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if (daemonize()) {
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guacd_log_error("Could not become a daemon.");
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exit(EXIT_FAILURE);
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}
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}
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/* Write PID file if requested */
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if (pidfile != NULL) {
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/* Attempt to open pidfile and write PID */
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FILE* pidf = fopen(pidfile, "w");
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if (pidf) {
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fprintf(pidf, "%d\n", getpid());
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fclose(pidf);
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}
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/* Fail if could not write PID file*/
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else {
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guacd_log_error("Could not write PID file: %s", strerror(errno));
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exit(EXIT_FAILURE);
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}
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}
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/* Ignore SIGPIPE */
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if (signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
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guacd_log_info("Could not set handler for SIGPIPE to ignore. "
|
|
"SIGPIPE may cause termination of the daemon.");
|
|
}
|
|
|
|
/* Ignore SIGCHLD (force automatic removal of children) */
|
|
if (signal(SIGCHLD, SIG_IGN) == SIG_ERR) {
|
|
guacd_log_info("Could not set handler for SIGCHLD to ignore. "
|
|
"Child processes may pile up in the process table.");
|
|
}
|
|
|
|
/* Log listening status */
|
|
guacd_log_info("Listening on host %s, port %s", bound_address, bound_port);
|
|
|
|
/* Free addresses */
|
|
freeaddrinfo(addresses);
|
|
|
|
/* Daemon loop */
|
|
for (;;) {
|
|
|
|
pid_t child_pid;
|
|
|
|
/* Listen for connections */
|
|
if (listen(socket_fd, 5) < 0) {
|
|
guacd_log_error("Could not listen on socket: %s", strerror(errno));
|
|
return 3;
|
|
}
|
|
|
|
/* Accept connection */
|
|
client_addr_len = sizeof(client_addr);
|
|
connected_socket_fd = accept(socket_fd,
|
|
(struct sockaddr*) &client_addr, &client_addr_len);
|
|
|
|
if (connected_socket_fd < 0) {
|
|
guacd_log_error("Could not accept client connection: %s",
|
|
strerror(errno));
|
|
return 3;
|
|
}
|
|
|
|
/*
|
|
* Once connection is accepted, send child into background.
|
|
*
|
|
* Note that we prefer fork() over threads for connection-handling
|
|
* processes as they give each connection its own memory area, and
|
|
* isolate the main daemon and other connections from errors in any
|
|
* particular client plugin.
|
|
*/
|
|
|
|
child_pid = fork();
|
|
|
|
/* If error, log */
|
|
if (child_pid == -1)
|
|
guacd_log_error("Error forking child process: %s", strerror(errno));
|
|
|
|
/* If child, start client, and exit when finished */
|
|
else if (child_pid == 0) {
|
|
|
|
guac_socket* socket;
|
|
|
|
#ifdef ENABLE_SSL
|
|
|
|
/* If SSL chosen, use it */
|
|
if (ssl_context != NULL) {
|
|
socket = guac_socket_open_secure(ssl_context, connected_socket_fd);
|
|
if (socket == NULL) {
|
|
guacd_log_guac_error("Error opening secure connection");
|
|
return 0;
|
|
}
|
|
}
|
|
else
|
|
socket = guac_socket_open(connected_socket_fd);
|
|
#else
|
|
/* Open guac_socket */
|
|
socket = guac_socket_open(connected_socket_fd);
|
|
#endif
|
|
|
|
guacd_handle_connection(socket);
|
|
close(connected_socket_fd);
|
|
return 0;
|
|
}
|
|
|
|
/* If parent, close reference to child's descriptor */
|
|
else if (close(connected_socket_fd) < 0) {
|
|
guacd_log_error("Error closing daemon reference to "
|
|
"child descriptor: %s", strerror(errno));
|
|
}
|
|
|
|
}
|
|
|
|
/* Close socket */
|
|
if (close(socket_fd) < 0) {
|
|
guacd_log_error("Could not close socket: %s", strerror(errno));
|
|
return 3;
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|