system.c revision 55837 
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 55837 2000-01-12 09:23:48Z jasone $
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 <sys/types.h>
41#include <sys/wait.h>
42#include <signal.h>
43#include <stdlib.h>
44#include <stddef.h>
45#include <unistd.h>
46#include <paths.h>
47#include <errno.h>
48
49int
50__system(command)
51	const char *command;
52{
53	pid_t pid;
54	int pstat;
55	struct sigaction ign, intact, quitact;
56	sigset_t newsigblock, oldsigblock;
57
58	if (!command)		/* just checking... */
59		return(1);
60
61	/*
62	 * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
63	 * existing signal dispositions.
64	 */
65	ign.sa_handler = SIG_IGN;
66	(void)sigemptyset(&ign.sa_mask);
67	ign.sa_flags = 0;
68	(void)sigaction(SIGINT, &ign, &intact);
69	(void)sigaction(SIGQUIT, &ign, &quitact);
70	(void)sigemptyset(&newsigblock);
71	(void)sigaddset(&newsigblock, SIGCHLD);
72	(void)sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
73	switch(pid = fork()) {
74	case -1:			/* error */
75		break;
76	case 0:				/* child */
77		/*
78		 * Restore original signal dispositions and exec the command.
79		 */
80		(void)sigaction(SIGINT, &intact, NULL);
81		(void)sigaction(SIGQUIT,  &quitact, NULL);
82		(void)sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
83		execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
84		_exit(127);
85	default:			/* parent */
86		do {
87			pid = _libc_waitpid(pid, &pstat, 0);
88		} while (pid == -1 && errno == EINTR);
89		break;
90	}
91	(void)sigaction(SIGINT, &intact, NULL);
92	(void)sigaction(SIGQUIT,  &quitact, NULL);
93	(void)sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
94	return(pid == -1 ? -1 : pstat);
95}
96
97__weak_reference(__system, _libc_system);
98__weak_reference(_libc_system, system);
99