stdlib/FreeBSD/system.c

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