aboutsummaryrefslogtreecommitdiff
path: root/coreutils/timeout.c
blob: 8485e1e7d7f281c95b5c84f5360662da38aa6d25 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * COPYING NOTES
 *
 * timeout.c -- a timeout handler for shell commands
 *
 * Copyright (C) 2005-6, Roberto A. Foglietta <me@roberto.foglietta.name>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; version 2 of the License.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * REVISION NOTES:
 * released 17-11-2005 by Roberto A. Foglietta
 * talarm   04-12-2005 by Roberto A. Foglietta
 * modified 05-12-2005 by Roberto A. Foglietta
 * sizerdct 06-12-2005 by Roberto A. Foglietta
 * splitszf 12-05-2006 by Roberto A. Foglietta
 * rewrite  14-11-2008 vda
 */
//config:config TIMEOUT
//config:	bool "timeout (6 kb)"
//config:	default y
//config:	help
//config:	Runs a program and watches it. If it does not terminate in
//config:	specified number of seconds, it is sent a signal.

//applet:IF_TIMEOUT(APPLET(timeout, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_TIMEOUT) += timeout.o

//usage:#define timeout_trivial_usage
//usage:       "[-s SIG] SECS PROG ARGS"
//usage:#define timeout_full_usage "\n\n"
//usage:       "Run PROG. Send SIG to it if it is not gone in SECS seconds.\n"
//usage:       "Default SIG: TERM."

#include "libbb.h"

int timeout_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int timeout_main(int argc UNUSED_PARAM, char **argv)
{
	int signo;
	int status;
	int parent = 0;
	int timeout;
	pid_t pid;
#if !BB_MMU
	char *sv1, *sv2;
#endif
	const char *opt_s = "TERM";

	/* -p option is not documented, it is needed to support NOMMU. */

	/* -t SECONDS; -p PARENT_PID */
	/* '+': stop at first non-option */
	getopt32(argv, "+s:" USE_FOR_NOMMU("p:+"), &opt_s, &parent);
	/*argv += optind; - no, wait for bb_daemonize_or_rexec! */

	signo = get_signum(opt_s);
	if (signo < 0)
		bb_error_msg_and_die("unknown signal '%s'", opt_s);

	if (!argv[optind])
		bb_show_usage();
	timeout = parse_duration_str(argv[optind++]);
	if (!argv[optind]) /* no PROG? */
		bb_show_usage();

	/* We want to create a grandchild which will watch
	 * and kill the grandparent. Other methods:
	 * making parent watch child disrupts parent<->child link
	 * (example: "tcpsvd 0.0.0.0 1234 timeout service_prog" -
	 * it's better if service_prog is a child of tcpsvd!),
	 * making child watch parent results in programs having
	 * unexpected children.	*/

	if (parent) /* we were re-execed, already grandchild */
		goto grandchild;

#if !BB_MMU
	sv1 = argv[optind];
	sv2 = argv[optind + 1];
#endif
	pid = xvfork();
	if (pid == 0) {
		/* Child: spawn grandchild and exit */
		parent = getppid();
#if !BB_MMU
		argv[optind] = xasprintf("-p%u", parent);
		argv[optind + 1] = NULL;
#endif
		/* NB: exits with nonzero on error: */
		bb_daemonize_or_rexec(0, argv);
		/* Here we are grandchild. Sleep, then kill grandparent */
 grandchild:
		/* Just sleep(HUGE_NUM); kill(parent) may kill wrong process! */
		while (1) {
			sleep1();
			if (--timeout <= 0)
				break;
			if (kill(parent, 0)) {
				/* process is gone */
				return EXIT_SUCCESS;
			}
		}
		kill(parent, signo);
		return EXIT_SUCCESS;
	}

	/* Parent */
	wait(&status); /* wait for child to die */
	/* Did intermediate [v]fork or exec fail? */
	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
		return EXIT_FAILURE;
	/* Ok, exec a program as requested */
	argv += optind;
#if !BB_MMU
	argv[0] = sv1;
	argv[1] = sv2;
#endif
	BB_EXECVP_or_die(argv);
}