busybox/miscutils/setsid.c

/* vi: set sw=4 ts=4: */
/*
 * setsid.c -- execute a command in a new session
 * Rick Sladkey <jrs@world.std.com>
 * In the public domain.
 *
 * 1999-02-22 Arkadiusz Mickiewicz <misiek@pld.ORG.PL>
 * - added Native Language Support
 *
 * 2001-01-18 John Fremlin <vii@penguinpowered.com>
 * - fork in case we are process group leader
 *
 * 2004-11-12 Paul Fox
 * - busyboxed
 */

#include "libbb.h"

int setsid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int setsid_main(int argc UNUSED_PARAM, char **argv)
{
	if (!argv[1])
		bb_show_usage();

	/* setsid() is allowed only when we are not a process group leader.
	 * Otherwise our PID serves as PGID of some existing process group
	 * and cannot be used as PGID of a new process group. */
	if (setsid() < 0) {
		pid_t pid = fork_or_rexec(argv);
		if (pid != 0) {
			/* parent */
			/* TODO:
			 * we can waitpid(pid, &status, 0) and then even
			 * emulate exitcode, making the behavior consistent
			 * in both forked and non forked cases.
			 * However, the code is larger and upstream
			 * does not do such trick.
			 */
			exit(EXIT_SUCCESS);
		}

		/* child */
		/* now there should be no error: */
		setsid();
	}

	argv++;
	BB_EXECVP_or_die(argv);
}
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
19	int setsid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
20	int 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	}