1/* vi: set sw=4 ts=4: */
2/* nohup - invoke a utility immune to hangups.
3 *
4 * Busybox version based on nohup specification at
5 * http://www.opengroup.org/onlinepubs/007904975/utilities/nohup.html
6 *
7 * Copyright 2006 Rob Landley <rob@landley.net>
8 * Copyright 2006 Bernhard Fischer
9 *
10 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
11 */
12
13#include "libbb.h"
14
15int nohup_main(int argc, char **argv);
16int nohup_main(int argc, char **argv)
17{
18	int nullfd;
19	const char *nohupout;
20	char *home = NULL;
21
22	xfunc_error_retval = 127;
23
24	if (argc < 2) bb_show_usage();
25
26	nullfd = xopen(bb_dev_null, O_WRONLY|O_APPEND);
27	/* If stdin is a tty, detach from it. */
28	if (isatty(STDIN_FILENO))
29		dup2(nullfd, STDIN_FILENO);
30
31	nohupout = "nohup.out";
32	/* Redirect stdout to nohup.out, either in "." or in "$HOME". */
33	if (isatty(STDOUT_FILENO)) {
34		close(STDOUT_FILENO);
35		if (open(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR) < 0) {
36			home = getenv("HOME");
37			if (home) {
38				nohupout = concat_path_file(home, nohupout);
39				xopen3(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR);
40			}
41		}
42	} else dup2(nullfd, STDOUT_FILENO);
43
44	/* If we have a tty on stderr, announce filename and redirect to stdout.
45	 * Else redirect to /dev/null.
46	 */
47	if (isatty(STDERR_FILENO)) {
48		bb_error_msg("appending to %s", nohupout);
49		dup2(STDOUT_FILENO, STDERR_FILENO);
50	} else dup2(nullfd, STDERR_FILENO);
51
52	if (nullfd > 2)
53		close(nullfd);
54	signal(SIGHUP, SIG_IGN);
55
56	BB_EXECVP(argv[1], argv+1);
57	if (ENABLE_FEATURE_CLEAN_UP && home)
58		free((char*)nohupout);
59	bb_perror_msg_and_die("%s", argv[1]);
60}
61