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/* Copyright (C) 1991-1999, 2000 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, write to the Free

   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA

   02111-1307 USA.  */

#include <stddef.h>

#include <stdlib.h>

#include <unistd.h>

#include <sys/wait.h>

#include <signal.h>

#include <sys/types.h>

#include <errno.h>

#include <machine/weakalias.h>

#ifndef HAVE_GNU_LD

#define __environ       environ

#endif

#define SHELL_PATH      "/bin/sh"       /* Path of the shell.  */

#define SHELL_NAME      "sh"            /* Name to give it.  */

/* Execute LINE as a shell command, returning its status.  */

int

__libc_system (const char *line)

{

  int status, save;

  pid_t pid;

  struct sigaction sa, intr, quit;

#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD

  sigset_t block, omask;

#endif

  if (line == NULL)

    /* Check that we have a command processor available.  It might

       not be available after a chroot(), for example.  */

    return __libc_system ("exit 0") == 0;

  sa.sa_handler = SIG_IGN;

  sa.sa_flags = 0;

  sigemptyset (&sa.sa_mask);

  if (sigaction (SIGINT, &sa, &intr) < 0)

    return -1;

  if (sigaction (SIGQUIT, &sa, &quit) < 0)

    {

      save = errno;

      (void) sigaction (SIGINT, &intr, (struct sigaction *) NULL);

      errno = save;

      return -1;

    }

#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD

/* SCO 3.2v4 has a bug where `waitpid' will never return if SIGCHLD is

   blocked.  This makes it impossible for `system' to be implemented in

   compliance with POSIX.2-1992.  They have acknowledged that this is a bug

   but I have not seen nor heard of any forthcoming fix.  */

  sigemptyset (&block);

  sigaddset (&block, SIGCHLD);

  save = errno;

  if (sigprocmask (SIG_BLOCK, &block, &omask) < 0)

    {

      if (errno == ENOSYS)

        errno = save;

      else

        {

          save = errno;

          (void) sigaction (SIGINT, &intr, (struct sigaction *) NULL);

          (void) sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);

          errno = save;

          return -1;

        }

    }

# define UNBLOCK sigprocmask (SIG_SETMASK, &omask, (sigset_t *) NULL)

#else

# define UNBLOCK 0

#endif

  pid = fork ();

  if (pid == (pid_t) 0)

    {

      /* Child side.  */

      const char *new_argv[4];

      new_argv[0] = SHELL_NAME;

      new_argv[1] = "-c";

      new_argv[2] = line;

      new_argv[3] = NULL;

      /* Restore the signals.  */

      (void) sigaction (SIGINT, &intr, (struct sigaction *) NULL);

      (void) sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);

      (void) UNBLOCK;

      /* Exec the shell.  */

      (void) execve (SHELL_PATH, (char *const *) new_argv, __environ);

      _exit (127);

    }

  else if (pid < (pid_t) 0)

    /* The fork failed.  */

    status = -1;

  else

    /* Parent side.  */

    {

#ifdef  NO_WAITPID

      pid_t child;

      do

        {

          child = wait (&status);

          if (child <= -1 && errno != EINTR)

            {

              status = -1;

              break;

            }

          /* Note that pid cannot be <= -1 and therefore the loop continues

             when wait returned with EINTR.  */

        }

      while (child != pid);

#else

      int n;

      do

        n = waitpid (pid, &status, 0);

      while (n == -1 && errno == EINTR);

      if (n != pid)

        status = -1;

#endif

    }

  save = errno;

  if ((sigaction (SIGINT, &intr, (struct sigaction *) NULL) |

       sigaction (SIGQUIT, &quit, (struct sigaction *) NULL) |

       UNBLOCK) != 0)

    {

      if (errno == ENOSYS)

        errno = save;

      else

        return -1;

    }

  return status;

}

weak_alias (__libc_system, system)