xref: /netbsd-src/lib/libc/stdlib/system.c (revision 21e37cc72a480a47828990a439cde7ac9ffaf0c6)
1 /*	$NetBSD: system.c,v 1.19 2003/08/07 16:43:45 agc Exp $	*/
2 
3 /*
4  * Copyright (c) 1988, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)system.c	8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: system.c,v 1.19 2003/08/07 16:43:45 agc Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include "namespace.h"
42 #include <sys/types.h>
43 #include <sys/wait.h>
44 #include <errno.h>
45 #include <signal.h>
46 #include <stdlib.h>
47 #include <unistd.h>
48 #include <paths.h>
49 #include "reentrant.h"
50 
51 #ifdef _REENTRANT
52 extern rwlock_t __environ_lock;
53 #endif
54 extern char **environ;
55 
56 int
57 system(command)
58 	const char *command;
59 {
60 	pid_t pid;
61 	struct sigaction intsa, quitsa, sa;
62 	sigset_t nmask, omask;
63 	int pstat;
64 	char *argp[] = {"sh", "-c", /* LINTED */(char *)command, NULL};
65 
66 	if (command == NULL)		/* just checking... */
67 		return(1);
68 
69 	sa.sa_handler = SIG_IGN;
70 	sigemptyset(&sa.sa_mask);
71 	sa.sa_flags = 0;
72 
73 	if (sigaction(SIGINT, &sa, &intsa) == -1)
74 		return -1;
75 	if (sigaction(SIGQUIT, &sa, &quitsa) == -1)
76 		return -1;
77 
78 	sigemptyset(&nmask);
79 	sigaddset(&nmask, SIGCHLD);
80 	if (sigprocmask(SIG_BLOCK, &nmask, &omask) == -1)
81 		return -1;
82 
83 	rwlock_rdlock(&__environ_lock);
84 	switch(pid = vfork()) {
85 	case -1:			/* error */
86 		rwlock_unlock(&__environ_lock);
87 		sigaction(SIGINT, &intsa, NULL);
88 		sigaction(SIGQUIT, &quitsa, NULL);
89 		(void)sigprocmask(SIG_SETMASK, &omask, NULL);
90 		return -1;
91 	case 0:				/* child */
92 		sigaction(SIGINT, &intsa, NULL);
93 		sigaction(SIGQUIT, &quitsa, NULL);
94 		(void)sigprocmask(SIG_SETMASK, &omask, NULL);
95 		execve(_PATH_BSHELL, argp, environ);
96 		_exit(127);
97 	}
98 	rwlock_unlock(&__environ_lock);
99 
100 	while (waitpid(pid, &pstat, 0) == -1) {
101 		if (errno != EINTR) {
102 			pstat = -1;
103 			break;
104 		}
105 	}
106 
107 	sigaction(SIGINT, &intsa, NULL);
108 	sigaction(SIGQUIT, &quitsa, NULL);
109 	(void)sigprocmask(SIG_SETMASK, &omask, NULL);
110 
111 	return (pstat);
112 }
113