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   * 4. 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  #pragma clang diagnostic push
 31  #pragma clang diagnostic ignored "-Wstrict-prototypes"
 32  
 33  #if defined(LIBC_SCCS) && !defined(lint)
 34  static char sccsid[] = "@(#)system.c	8.1 (Berkeley) 6/4/93";
 35  #endif /* LIBC_SCCS and not lint */
 36  #include <sys/cdefs.h>
 37  __FBSDID("$FreeBSD: src/lib/libc/stdlib/system.c,v 1.11 2007/01/09 00:28:10 imp Exp $");
 38  
 39  #include "namespace.h"
 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 <spawn.h>
 47  #include <paths.h>
 48  #include <errno.h>
 49  #include "un-namespace.h"
 50  #include "libc_private.h"
 51  
 52  #include <crt_externs.h>
 53  #define environ (*_NSGetEnviron())
 54  
 55  #include <TargetConditionals.h>
 56  
 57  #if __DARWIN_UNIX03
 58  #include <pthread.h>
 59  
 60  #if !(TARGET_OS_IPHONE && (TARGET_OS_SIMULATOR || !TARGET_OS_IOS))
 61  static pthread_mutex_t __systemfn_mutex = PTHREAD_MUTEX_INITIALIZER;
 62  #endif
 63  extern int __unix_conforming;
 64  #endif /* __DARWIN_UNIX03 */
 65  
 66  int
 67  __system(command)
 68  	const char *command;
 69  {
 70  #if TARGET_OS_IPHONE && (TARGET_OS_SIMULATOR || !TARGET_OS_IOS)
 71  	// Don't abort() on iOS for now
 72  	LIBC_ABORT("system() is not supported on this platform.");
 73  #else
 74  	pid_t pid, savedpid;
 75  	int pstat, err;
 76  	struct sigaction ign, intact, quitact;
 77  	sigset_t newsigblock, oldsigblock, defaultsig;
 78  	posix_spawnattr_t attr;
 79  	short flags = POSIX_SPAWN_SETSIGMASK;
 80  	const char *argv[] = {"sh", "-c", command, NULL};
 81  
 82  #if __DARWIN_UNIX03
 83  	if (__unix_conforming == 0)
 84  		__unix_conforming = 1;
 85  #ifdef VARIANT_CANCELABLE
 86  	pthread_testcancel();
 87  #endif /* VARIANT_CANCELABLE */
 88  #endif /* __DARWIN_UNIX03 */
 89  
 90  	if (!command) {		/* just checking... */
 91  #if TARGET_OS_IPHONE
 92  		return(0);
 93  #else
 94  		if (access(_PATH_BSHELL, F_OK) == -1)	/* if no sh or no access */
 95  			return(0);
 96  		else
 97  			return(1);
 98  #endif
 99  	}
100  
101  	if ((err = posix_spawnattr_init(&attr)) != 0) {
102  		errno = err;
103  		return -1;
104  	}
105  	(void)sigemptyset(&defaultsig);
106  
107  #if __DARWIN_UNIX03
108  	pthread_mutex_lock(&__systemfn_mutex);
109  #endif /* __DARWIN_UNIX03 */
110  	/*
111  	 * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
112  	 * existing signal dispositions.
113  	 */
114  	ign.sa_handler = SIG_IGN;
115  	(void)sigemptyset(&ign.sa_mask);
116  	ign.sa_flags = 0;
117  	(void)_sigaction(SIGINT, &ign, &intact);
118  	if (intact.sa_handler != SIG_IGN) {
119  		sigaddset(&defaultsig, SIGINT);
120  		flags |= POSIX_SPAWN_SETSIGDEF;
121  	}
122  	(void)_sigaction(SIGQUIT, &ign, &quitact);
123  	if (quitact.sa_handler != SIG_IGN) {
124  		sigaddset(&defaultsig, SIGQUIT);
125  		flags |= POSIX_SPAWN_SETSIGDEF;
126  	}
127  	(void)sigemptyset(&newsigblock);
128  	(void)sigaddset(&newsigblock, SIGCHLD);
129  	(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
130  	(void)posix_spawnattr_setsigmask(&attr, &oldsigblock);
131  	if (flags & POSIX_SPAWN_SETSIGDEF) {
132  		(void)posix_spawnattr_setsigdefault(&attr, &defaultsig);
133  	}
134  	(void)posix_spawnattr_setflags(&attr, flags);
135  
136  	err = posix_spawn(&pid, _PATH_BSHELL, NULL, &attr, (char *const *)argv, environ);
137  	(void)posix_spawnattr_destroy(&attr);
138  	if (err == 0) {
139  		savedpid = pid;
140  		do {
141  			pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
142  		} while (pid == -1 && errno == EINTR);
143  		if (pid == -1) pstat = -1;
144  	} else if (err == ENOMEM || err == EAGAIN) { /* as if fork failed */
145  		pstat = -1;
146  	} else {
147  		pstat = W_EXITCODE(127, 0); /* couldn't exec shell */
148  	}
149  
150  	(void)_sigaction(SIGINT, &intact, NULL);
151  	(void)_sigaction(SIGQUIT,  &quitact, NULL);
152  	(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
153  #if __DARWIN_UNIX03
154  	pthread_mutex_unlock(&__systemfn_mutex);
155  #endif /* __DARWIN_UNIX03 */
156  	return(pstat);
157  #endif /* TARGET_OS_IPHONE && (TARGET_OS_SIMULATOR || !TARGET_OS_IOS) */
158  }
159  
160  __weak_reference(__system, system);
161  __weak_reference(__system, _system);
162  
163  #pragma clang diagnostic pop