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  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/lib/libc/stdlib/system.c,v 1.5.2.2 2001/10/10 12:50:22 alfred Exp $
  34  * $DragonFly: src/lib/libc/stdlib/system.c,v 1.5 2005/11/20 12:37:49 swildner Exp $
  35  *
  36  * @(#)system.c 8.1 (Berkeley) 6/4/93
  37  */
  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 <paths.h>
  47 #include <errno.h>
  48 #include "un-namespace.h"
  49 #include "libc_private.h"
  50
  51 int     __system(const char *);
  52
  53 int
  54 __system(const char *command)
  55 {
  56         pid_t pid, savedpid;
  57         int pstat;
  58         struct sigaction ign, intact, quitact;
  59         sigset_t newsigblock, oldsigblock;
  60
  61         if (!command)           /* just checking... */
  62                 return(1);
  63
  64         /*
  65          * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
  66          * existing signal dispositions.
  67          */
  68         ign.sa_handler = SIG_IGN;
  69         sigemptyset(&ign.sa_mask);
  70         ign.sa_flags = 0;
  71         _sigaction(SIGINT, &ign, &intact);
  72         _sigaction(SIGQUIT, &ign, &quitact);
  73         sigemptyset(&newsigblock);
  74         sigaddset(&newsigblock, SIGCHLD);
  75         _sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
  76         switch(pid = fork()) {
  77         case -1:                        /* error */
  78                 break;
  79         case 0:                         /* child */
  80                 /*
  81                  * Restore original signal dispositions and exec the command.
  82                  */
  83                 _sigaction(SIGINT, &intact, NULL);
  84                 _sigaction(SIGQUIT,  &quitact, NULL);
  85                 _sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
  86                 execl(_PATH_BSHELL, "sh", "-c", command, (char *)NULL);
  87                 _exit(127);
  88         default:                        /* parent */
  89                 savedpid = pid;
  90                 do {
  91                         pid = _wait4(savedpid, &pstat, 0, (struct rusage *)0);
  92                 } while (pid == -1 && errno == EINTR);
  93                 break;
  94         }
  95         _sigaction(SIGINT, &intact, NULL);
  96         _sigaction(SIGQUIT,  &quitact, NULL);
  97         _sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
  98         return(pid == -1 ? -1 : pstat);
  99 }
 100
 101 __weak_reference(__system, system);
 102 __weak_reference(__system, _system);