lib/libc/stdlib/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  * @(#)system.c 8.1 (Berkeley) 6/4/93
  30  * $FreeBSD: src/lib/libc/stdlib/system.c,v 1.11 2007/01/09 00:28:10 imp Exp $
  31  * $DragonFly: src/lib/libc/stdlib/system.c,v 1.5 2005/11/20 12:37:49 swildner Exp $
  32  */
  33
  34 #include "namespace.h"
  35 #include <sys/types.h>
  36 #include <sys/wait.h>
  37 #include <signal.h>
  38 #include <stdlib.h>
  39 #include <stddef.h>
  40 #include <unistd.h>
  41 #include <paths.h>
  42 #include <errno.h>
  43 #include "un-namespace.h"
  44 #include "libc_private.h"
  45
  46 int
  47 __system(const char *command)
  48 {
  49         pid_t pid, savedpid;
  50         int pstat;
  51         struct sigaction ign, intact, quitact;
  52         sigset_t newsigblock, oldsigblock;
  53
  54         if (!command)           /* just checking... */
  55                 return(1);
  56
  57         /*
  58          * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
  59          * existing signal dispositions.
  60          */
  61         ign.sa_handler = SIG_IGN;
  62         sigemptyset(&ign.sa_mask);
  63         ign.sa_flags = 0;
  64         _sigaction(SIGINT, &ign, &intact);
  65         _sigaction(SIGQUIT, &ign, &quitact);
  66         sigemptyset(&newsigblock);
  67         sigaddset(&newsigblock, SIGCHLD);
  68         _sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
  69         switch(pid = fork()) {
  70         case -1:                        /* error */
  71                 break;
  72         case 0:                         /* child */
  73                 /*
  74                  * Restore original signal dispositions and exec the command.
  75                  */
  76                 _sigaction(SIGINT, &intact, NULL);
  77                 _sigaction(SIGQUIT,  &quitact, NULL);
  78                 _sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
  79                 execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
  80                 _exit(127);
  81         default:                        /* parent */
  82                 savedpid = pid;
  83                 do {
  84                         pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
  85                 } while (pid == -1 && errno == EINTR);
  86                 break;
  87         }
  88         _sigaction(SIGINT, &intact, NULL);
  89         _sigaction(SIGQUIT,  &quitact, NULL);
  90         _sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
  91         return(pid == -1 ? -1 : pstat);
  92 }
  93
  94 __weak_reference(__system, system);
  95 __weak_reference(__system, _system);