system.c revision 251672 
1/*
2 * Copyright (c) 1988, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)system.c	8.1 (Berkeley) 6/4/93";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/lib/libc/stdlib/system.c 251672 2013-06-13 00:19:30Z emaste $");
35
36#include "namespace.h"
37#include <sys/types.h>
38#include <sys/wait.h>
39#include <signal.h>
40#include <stdlib.h>
41#include <stddef.h>
42#include <unistd.h>
43#include <paths.h>
44#include <errno.h>
45#include "un-namespace.h"
46#include "libc_private.h"
47
48int
49__system(const char *command)
50{
51	pid_t pid, savedpid;
52	int pstat;
53	struct sigaction ign, intact, quitact;
54	sigset_t newsigblock, oldsigblock;
55
56	if (!command)		/* just checking... */
57		return(1);
58
59	/*
60	 * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
61	 * existing signal dispositions.
62	 */
63	ign.sa_handler = SIG_IGN;
64	(void)sigemptyset(&ign.sa_mask);
65	ign.sa_flags = 0;
66	(void)_sigaction(SIGINT, &ign, &intact);
67	(void)_sigaction(SIGQUIT, &ign, &quitact);
68	(void)sigemptyset(&newsigblock);
69	(void)sigaddset(&newsigblock, SIGCHLD);
70	(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
71	switch(pid = fork()) {
72	case -1:			/* error */
73		break;
74	case 0:				/* child */
75		/*
76		 * Restore original signal dispositions and exec the command.
77		 */
78		(void)_sigaction(SIGINT, &intact, NULL);
79		(void)_sigaction(SIGQUIT,  &quitact, NULL);
80		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
81		execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
82		_exit(127);
83	default:			/* parent */
84		savedpid = pid;
85		do {
86			pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
87		} while (pid == -1 && errno == EINTR);
88		break;
89	}
90	(void)_sigaction(SIGINT, &intact, NULL);
91	(void)_sigaction(SIGQUIT,  &quitact, NULL);
92	(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
93	return(pid == -1 ? -1 : pstat);
94}
95
96__weak_reference(__system, system);
97__weak_reference(__system, _system);
98