1/* vi: set sw=4 ts=4: */
2/*
3 * setsid.c -- execute a command in a new session
4 * Rick Sladkey <jrs@world.std.com>
5 * In the public domain.
6 *
7 * 1999-02-22 Arkadiusz Mickiewicz <misiek@pld.ORG.PL>
8 * - added Native Language Support
9 *
10 * 2001-01-18 John Fremlin <vii@penguinpowered.com>
11 * - fork in case we are process group leader
12 *
13 * 2004-11-12 Paul Fox
14 * - busyboxed
15 */
16
17#include "libbb.h"
18
19int setsid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
20int setsid_main(int argc UNUSED_PARAM, char **argv)
21{
22	if (!argv[1])
23		bb_show_usage();
24
25	/* setsid() is allowed only when we are not a process group leader.
26	 * Otherwise our PID serves as PGID of some existing process group
27	 * and cannot be used as PGID of a new process group. */
28	if (setsid() < 0) {
29		pid_t pid = fork_or_rexec(argv);
30		if (pid != 0) {
31			/* parent */
32			/* TODO:
33			 * we can waitpid(pid, &status, 0) and then even
34			 * emulate exitcode, making the behavior consistent
35			 * in both forked and non forked cases.
36			 * However, the code is larger and upstream
37			 * does not do such trick.
38			 */
39			exit(EXIT_SUCCESS);
40		}
41
42		/* child */
43		/* now there should be no error: */
44		setsid();
45	}
46
47	argv++;
48	BB_EXECVP_or_die(argv);
49}
50