sys-utils/setsid.c

   1 /*
   2  * setsid.c -- execute a command in a new session
   3  * Rick Sladkey <jrs@world.std.com>
   4  * In the public domain.
   5  *
   6  * 1999-02-22 Arkadiusz Miśkiewicz <misiek@pld.ORG.PL>
   7  * - added Native Language Support
   8  *
   9  * 2001-01-18 John Fremlin <vii@penguinpowered.com>
  10  * - fork in case we are process group leader
  11  *
  12  * 2008-08-20 Daniel Kahn Gillmor <dkg@fifthhorseman.net>
  13  * - if forked, wait on child process and emit its return code.
  14  */
  15
  16 #include <getopt.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19 #include <unistd.h>
  20 #include <sys/ioctl.h>
  21 #include <sys/types.h>
  22 #include <sys/wait.h>
  23
  24 #include "c.h"
  25 #include "nls.h"
  26 #include "closestream.h"
  27
  28 static void __attribute__((__noreturn__)) usage(void)
  29 {
  30         FILE *out = stdout;
  31         fputs(USAGE_HEADER, out);
  32         fprintf(out, _(
  33                 " %s [options] <program> [arguments ...]\n"),
  34                 program_invocation_short_name);
  35
  36         fputs(USAGE_SEPARATOR, out);
  37         fputs(_("Run a program in a new session.\n"), out);
  38
  39         fputs(USAGE_OPTIONS, out);
  40         fputs(_(" -c, --ctty     set the controlling terminal to the current one\n"), out);
  41         fputs(_(" -w, --wait     wait program to exit, and use the same return\n"), out);
  42
  43         printf(USAGE_HELP_OPTIONS(16));
  44
  45         printf(USAGE_MAN_TAIL("setsid(1)"));
  46         exit(EXIT_SUCCESS);
  47 }
  48
  49 int main(int argc, char **argv)
  50 {
  51         int ch;
  52         int ctty = 0;
  53         pid_t pid;
  54         int status = 0;
  55
  56         static const struct option longopts[] = {
  57                 {"ctty", no_argument, NULL, 'c'},
  58                 {"wait", no_argument, NULL, 'w'},
  59                 {"version", no_argument, NULL, 'V'},
  60                 {"help", no_argument, NULL, 'h'},
  61                 {NULL, 0, NULL, 0}
  62         };
  63
  64         setlocale(LC_ALL, "");
  65         bindtextdomain(PACKAGE, LOCALEDIR);
  66         textdomain(PACKAGE);
  67         atexit(close_stdout);
  68
  69         while ((ch = getopt_long(argc, argv, "+Vhcw", longopts, NULL)) != -1)
  70                 switch (ch) {
  71                 case 'V':
  72                         printf(UTIL_LINUX_VERSION);
  73                         return EXIT_SUCCESS;
  74                 case 'c':
  75                         ctty=1;
  76                         break;
  77                 case 'w':
  78                         status = 1;
  79                         break;
  80                 case 'h':
  81                         usage();
  82                 default:
  83                         errtryhelp(EXIT_FAILURE);
  84                 }
  85
  86         if (argc - optind < 1) {
  87                 warnx(_("no command specified"));
  88                 errtryhelp(EXIT_FAILURE);
  89         }
  90
  91         if (getpgrp() == getpid()) {
  92                 pid = fork();
  93                 switch (pid) {
  94                 case -1:
  95                         err(EXIT_FAILURE, _("fork"));
  96                 case 0:
  97                         /* child */
  98                         break;
  99                 default:
 100                         /* parent */
 101                         if (!status)
 102                                 return EXIT_SUCCESS;
 103                         if (wait(&status) != pid)
 104                                 err(EXIT_FAILURE, "wait");
 105                         if (WIFEXITED(status))
 106                                 return WEXITSTATUS(status);
 107                         err(status, _("child %d did not exit normally"), pid);
 108                 }
 109         }
 110         if (setsid() < 0)
 111                 /* cannot happen */
 112                 err(EXIT_FAILURE, _("setsid failed"));
 113
 114         if (ctty && ioctl(STDIN_FILENO, TIOCSCTTY, 1))
 115                 err(EXIT_FAILURE, _("failed to set the controlling terminal"));
 116         execvp(argv[optind], argv + optind);
 117         err(EXIT_FAILURE, _("failed to execute %s"), argv[optind]);
 118 }