sys-utils/setpgid.c

   1 /*
   2  * setpgid.c -- execute a command in a new process group
   3  * Daan De Meyer <daan.j.demeyer@gmail.com>
   4  * In the public domain.
   5  */
   6
   7 #include <getopt.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <signal.h>
  12
  13 #include "closestream.h"
  14
  15 static void __attribute__((__noreturn__)) usage(void)
  16 {
  17         FILE *out = stdout;
  18         fputs(USAGE_HEADER, out);
  19         fprintf(out, _(
  20                 " %s [options] <program> [arguments ...]\n"),
  21                 program_invocation_short_name);
  22
  23         fputs(USAGE_SEPARATOR, out);
  24         fputs(_("Run a program in a new process group.\n"), out);
  25
  26         fputs(USAGE_OPTIONS, out);
  27         fputs(_(" -f, --foregound     Make a foreground process group\n"), out);
  28
  29         fprintf(out, USAGE_HELP_OPTIONS(16));
  30
  31         fprintf(out, USAGE_MAN_TAIL("setpgid(1)"));
  32         exit(EXIT_SUCCESS);
  33 }
  34
  35 int main(int argc, char **argv)
  36 {
  37         int ch, foreground = 0, fd;
  38         sigset_t s, old;
  39
  40         static const struct option longopts[] = {
  41                 {"foreground", no_argument, NULL, 'f'},
  42                 {"version", no_argument, NULL, 'V'},
  43                 {"help", no_argument, NULL, 'h'},
  44                 {NULL, 0, NULL, 0}
  45         };
  46
  47         setlocale(LC_ALL, "");
  48         bindtextdomain(PACKAGE, LOCALEDIR);
  49         textdomain(PACKAGE);
  50         close_stdout_atexit();
  51
  52         while ((ch = getopt_long(argc, argv, "+Vh", longopts, NULL)) != -1)
  53                 switch (ch) {
  54                 case 'f':
  55                         foreground = 1;
  56                         break;
  57                 case 'h':
  58                         usage();
  59                 case 'V':
  60                         print_version(EXIT_SUCCESS);
  61                 default:
  62                         errtryhelp(EXIT_FAILURE);
  63                 }
  64
  65         if (argc - optind < 1) {
  66                 warnx(_("no command specified"));
  67                 errtryhelp(EXIT_FAILURE);
  68         }
  69
  70         if (setpgid(0, 0) < 0)
  71                 err(EXIT_FAILURE, _("setpgid failed"));
  72
  73         if (foreground) {
  74                 fd = open("/dev/tty", O_RDONLY|O_CLOEXEC);
  75                 if (fd >= 0) {
  76                         if (sigemptyset(&s) < 0)
  77                                 err(EXIT_FAILURE, _("sigemptyset failed"));
  78                         if (sigaddset(&s, SIGTTOU) < 0)
  79                                 err(EXIT_FAILURE, _("sigaddset failed"));
  80                         if (sigprocmask(SIG_BLOCK, &s, &old) < 0)
  81                                 err(EXIT_FAILURE, _("sigprocmask failed"));
  82                         if (tcsetpgrp(fd, getpgid(0)) < 0)
  83                                 err(EXIT_FAILURE, _("tcsetpgrp failed"));
  84                         if (sigprocmask(SIG_SETMASK, &old, NULL) < 0)
  85                                 err(EXIT_FAILURE, _("sigprocmask failed"));
  86                 }
  87         }
  88
  89         execvp(argv[optind], argv + optind);
  90         errexec(argv[optind]);
  91 }