xref: /freebsd/lib/libc/stdlib/system.c (revision bc96366c864c07ef352edb92017357917c75b36c)
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 <string.h>
43 #include <unistd.h>
44 #include <paths.h>
45 #include <errno.h>
46 #include "un-namespace.h"
47 #include "libc_private.h"
48 
49 #pragma weak system
50 int
51 system(const char *command)
52 {
53 
54 	return (((int (*)(const char *))
55 	    __libc_interposing[INTERPOS_system])(command));
56 }
57 
58 int
59 __libc_system(const char *command)
60 {
61 	pid_t pid, savedpid;
62 	int pstat;
63 	struct sigaction ign, intact, quitact;
64 	sigset_t newsigblock, oldsigblock;
65 
66 	if (!command)		/* just checking... */
67 		return(1);
68 
69 	(void)sigemptyset(&newsigblock);
70 	(void)sigaddset(&newsigblock, SIGCHLD);
71 	(void)sigaddset(&newsigblock, SIGINT);
72 	(void)sigaddset(&newsigblock, SIGQUIT);
73 	(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
74 	switch(pid = vfork()) {
75 	case -1:			/* error */
76 		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
77 		return (-1);
78 	case 0:				/* child */
79 		/*
80 		 * Restore original signal dispositions and exec the command.
81 		 */
82 		(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
83 		execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
84 		_exit(127);
85 	}
86 	/*
87 	 * If we are running means that the child has either completed
88 	 * its execve, or has failed.
89 	 * Block SIGINT/QUIT because sh -c handles it and wait for
90 	 * it to clean up.
91 	 */
92 	memset(&ign, 0, sizeof(ign));
93 	ign.sa_handler = SIG_IGN;
94 	(void)sigemptyset(&ign.sa_mask);
95 	(void)_sigaction(SIGINT, &ign, &intact);
96 	(void)_sigaction(SIGQUIT, &ign, &quitact);
97 	savedpid = pid;
98 	do {
99 		pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
100 	} while (pid == -1 && errno == EINTR);
101 	(void)_sigaction(SIGINT, &intact, NULL);
102 	(void)_sigaction(SIGQUIT,  &quitact, NULL);
103 	(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
104 	return(pid == -1 ? -1 : pstat);
105 }
106 
107 __weak_reference(__libc_system, __system);
108 __weak_reference(__libc_system, _system);
109