xref: /freebsd/lib/libc/stdlib/system.c (revision a98ff317388a00b992f1bf8404dee596f9383f5e)
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)
31 static char sccsid[] = "@(#)system.c	8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
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 
48 int
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