266 lines
7.1 KiB
C
266 lines
7.1 KiB
C
/*
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* Copyright © 2016 Broadcom
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is 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 (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* 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
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* THE 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
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <dix-config.h>
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#include <X11/Xfuncproto.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdbool.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 <sys/wait.h>
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#include <unistd.h>
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static void
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kill_server(int server_pid)
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{
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int ret = kill(server_pid, SIGTERM);
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int wstatus;
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if (ret) {
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fprintf(stderr, "Failed to send kill to the server: %s\n",
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strerror(errno));
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exit(1);
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}
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ret = waitpid(server_pid, &wstatus, 0);
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if (ret < 0) {
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fprintf(stderr, "Failed to wait for X to die: %s\n", strerror(errno));
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exit(1);
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}
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}
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_X_NORETURN static void
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usage(int argc, char **argv)
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{
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fprintf(stderr, "%s <client command> -- <server command>\n", argv[0]);
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exit(1);
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}
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static int server_displayfd;
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static const char *server_dead = "server_dead";
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static void
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handle_sigchld(int sig)
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{
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write(server_displayfd, server_dead, strlen(server_dead));
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}
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/* Starts the X server, returning its pid. */
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static int
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start_server(char *const *server_args)
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{
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int server_pid = fork();
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if (server_pid == -1) {
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fprintf(stderr, "Fork failed: %s\n", strerror(errno));
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exit(1);
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} else if (server_pid != 0) {
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/* Continue along the main process that will exec the client. */
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struct sigaction sa;
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sa.sa_handler = handle_sigchld;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
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if (sigaction(SIGCHLD, &sa, 0) == -1) {
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fprintf(stderr, "Failed to set up signal handler: %s\n",
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strerror(errno));
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exit(1);
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}
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return server_pid;
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}
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/* Execute the server. This only returns if an error occurred. */
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execvp(server_args[0], server_args);
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fprintf(stderr, "Error starting the server: %s\n", strerror(errno));
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exit(1);
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}
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/* Reads the display number out of the started server's display socket. */
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static int
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get_display(int displayfd)
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{
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char display_string[20];
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ssize_t ret;
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ret = read(displayfd, display_string, sizeof(display_string) - 1);
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if (ret <= 0) {
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fprintf(stderr, "Failed reading displayfd: %s\n", strerror(errno));
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exit(1);
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}
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/* We've read in the display number as a string terminated by
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* '\n', but not '\0'. Cap it and parse the number.
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*/
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display_string[ret] = '\0';
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if (strncmp(display_string, server_dead, strlen(server_dead)) == 0) {
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fprintf(stderr, "Server failed to start before setting up displayfd\n");
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exit(1);
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}
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return atoi(display_string);
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}
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static int
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start_client(char *const *client_args, int display)
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{
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char *display_string;
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int ret;
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int client_pid;
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ret = asprintf(&display_string, ":%d", display);
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if (ret < 0) {
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fprintf(stderr, "asprintf fail\n");
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exit(1);
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}
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ret = setenv("DISPLAY", display_string, true);
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if (ret) {
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fprintf(stderr, "Failed to set DISPLAY\n");
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exit(1);
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}
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client_pid = fork();
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if (client_pid == -1) {
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fprintf(stderr, "Fork failed: %s\n", strerror(errno));
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exit(1);
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} else if (client_pid) {
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int wstatus;
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ret = waitpid(client_pid, &wstatus, 0);
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if (ret < 0) {
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fprintf(stderr, "Error waiting for client to start: %s\n",
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strerror(errno));
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return 1;
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}
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if (!WIFEXITED(wstatus))
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return 1;
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return WEXITSTATUS(wstatus);
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} else {
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execvp(client_args[0], client_args);
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/* exec only returns if an error occurred. */
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fprintf(stderr, "Error starting the client: %s\n", strerror(errno));
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exit(1);
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}
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}
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/* Splits the incoming argc/argv into a pair of NULL-terminated arrays
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* of args.
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*/
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static void
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parse_args(int argc, char **argv,
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char * const **out_client_args,
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char * const **out_server_args,
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int displayfd)
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{
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/* We're stripping the -- and the program name, inserting two
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* NULLs, and also the -displayfd and fd number.
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*/
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char **args_storage = calloc(argc + 2, sizeof(char *));
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char *const *client_args;
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char *const *server_args = NULL;
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char **next_arg = args_storage;
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bool parsing_client = true;
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int i, ret;
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char *displayfd_string;
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if (!args_storage)
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exit(1);
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client_args = args_storage;
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for (i = 1; i < argc; i++) {
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if (strcmp(argv[i], "--") == 0) {
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if (!parsing_client)
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usage(argc, argv);
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/* Cap the client list */
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*next_arg = NULL;
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next_arg++;
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/* Move to adding into server_args. */
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server_args = next_arg;
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parsing_client = false;
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continue;
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}
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/* A sort of escaped "--" argument so we can nest server
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* invocations for testing.
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*/
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if (strcmp(argv[i], "----") == 0)
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*next_arg = (char *)"--";
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else
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*next_arg = argv[i];
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next_arg++;
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}
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if (client_args[0] == NULL || !server_args || server_args[0] == NULL)
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usage(argc, argv);
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/* Give the server -displayfd X */
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*next_arg = (char *)"-displayfd";
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next_arg++;
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ret = asprintf(&displayfd_string, "%d", displayfd);
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if (ret < 0) {
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fprintf(stderr, "asprintf fail\n");
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exit(1);
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}
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*next_arg = displayfd_string;
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next_arg++;
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*out_client_args = client_args;
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*out_server_args = server_args;
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}
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int
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main(int argc, char **argv)
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{
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char * const *client_args;
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char * const *server_args;
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int displayfd_pipe[2];
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int display, server_pid;
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int ret;
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ret = pipe(displayfd_pipe);
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if (ret) {
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fprintf(stderr, "Pipe creation failure: %s", strerror(errno));
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exit(1);
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}
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server_displayfd = displayfd_pipe[1];
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parse_args(argc, argv, &client_args, &server_args, server_displayfd);
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server_pid = start_server(server_args);
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display = get_display(displayfd_pipe[0]);
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ret = start_client(client_args, display);
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kill_server(server_pid);
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exit(ret);
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}
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