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 Mi¶kiewicz <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  */
  13
  14 #include <getopt.h>
  15 #include <stdio.h>
  16 #include <stdlib.h>
  17 #include <unistd.h>
  18 #include <termio.h>
  19
  20 #include "c.h"
  21 #include "nls.h"
  22
  23 static void __attribute__ ((__noreturn__)) usage(FILE * out)
  24 {
  25         fputs(USAGE_HEADER, out);
  26         fprintf(out, _(
  27                 " %s [options] <program> [arguments ...]\n"),
  28                 program_invocation_short_name);
  29
  30         fputs(USAGE_OPTIONS, out);
  31         fputs(_(" -c, --ctty     set the controlling terminal to the current one\n"),
  32                 out);
  33
  34         fputs(USAGE_HELP, out);
  35         fputs(USAGE_VERSION, out);
  36
  37         fprintf(out, USAGE_MAN_TAIL("setsid(1)"));
  38         exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
  39 }
  40
  41 int main(int argc, char **argv)
  42 {
  43         int ch;
  44         int ctty = 0;
  45
  46         static const struct option longopts[] = {
  47                 {"ctty", no_argument, NULL, 'c'},
  48                 {"version", no_argument, NULL, 'V'},
  49                 {"help", no_argument, NULL, 'h'},
  50                 {NULL, 0, NULL, 0}
  51         };
  52
  53         setlocale(LC_ALL, "");
  54         bindtextdomain(PACKAGE, LOCALEDIR);
  55         textdomain(PACKAGE);
  56
  57         while ((ch = getopt_long(argc, argv, "+Vhc", longopts, NULL)) != -1)
  58                 switch (ch) {
  59                 case 'V':
  60                         printf(UTIL_LINUX_VERSION);
  61                         return EXIT_SUCCESS;
  62                 case 'c':
  63                         ctty=1;
  64                         break;
  65                 case 'h':
  66                         usage(stdout);
  67                 default:
  68                         usage(stderr);
  69                 }
  70
  71         if (argc < 2)
  72                 usage(stderr);
  73
  74         if (getpgrp() == getpid()) {
  75                 switch (fork()) {
  76                 case -1:
  77                         err(EXIT_FAILURE, _("fork"));
  78                 case 0:
  79                         /* child */
  80                         break;
  81                 default:
  82                         /* parent */
  83                         return 0;
  84                 }
  85         }
  86         if (setsid() < 0)
  87                 /* cannot happen */
  88                 err(EXIT_FAILURE, _("setsid failed"));
  89
  90         if (ctty) {
  91                 if (ioctl(STDIN_FILENO, TIOCSCTTY, 1))
  92                         warn(_("failed to set the controlling terminal"));
  93         }
  94         execvp(argv[optind], argv + optind + 1);
  95         err(EXIT_FAILURE, _("execvp failed"));
  96 }