system.c revision 84418 
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. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: head/lib/libc/stdlib/system.c 84417 2001-10-03 11:01:39Z alfred $
34 */
35
36#if defined(LIBC_SCCS) && !defined(lint)
37static char sccsid[] = "@(#)system.c	8.1 (Berkeley) 6/4/93";
38#endif /* LIBC_SCCS and not lint */
39
40#include "namespace.h"
41#include <sys/types.h>
42#include <sys/wait.h>
43#include <signal.h>
44#include <stdlib.h>
45#include <stddef.h>
46#include <unistd.h>
47#include <paths.h>
48#include <errno.h>
49#include "un-namespace.h"
50#include "libc_private.h"
51
52int
53__system(command)
54	const char *command;
55{
56	pid_t pid, savedpid;
57	int pstat;
58	struct sigaction ign, intact, quitact;
59	sigset_t newsigblock, oldsigblock;
60
61	if (!command)		/* just checking... */
62		return(1);
63
64	/*
65	 * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
66	 * existing signal dispositions.
67	 */
68	ign.sa_handler = SIG_IGN;
69	(void)sigemptyset(&ign.sa_mask);
70	ign.sa_flags = 0;
71	(void)_sigaction(SIGINT, &ign, &intact);
72	(void)_sigaction(SIGQUIT, &ign, &quitact);
73	(void)sigemptyset(&newsigblock);
74	(void)sigaddset(&newsigblock, SIGCHLD);
75	(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
76	switch(pid = fork()) {
77	case -1:			/* error */
78		break;
79	case 0:				/* child */
80		/*
81		 * Restore original signal dispositions and exec the command.
82		 */
83		(void)_sigaction(SIGINT, &intact, NULL);
84		(void)_sigaction(SIGQUIT,  &quitact, NULL);
85		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
86		execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
87		_exit(127);
88	default:			/* parent */
89		savedpid = pid;
90		do {
91			pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
92		} while (pid == -1 && errno == EINTR);
93		break;
94	}
95	(void)_sigaction(SIGINT, &intact, NULL);
96	(void)_sigaction(SIGQUIT,  &quitact, NULL);
97	(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
98	return(pid == -1 ? -1 : pstat);
99}
100
101__weak_reference(__system, system);
102__weak_reference(__system, _system);
103