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/* Copyright (C) 1991, 1992, 1994, 1995 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/types.h>
#include <errno.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
DEFUN(system, (line), register 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)
return 1;
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 = __vfork ();
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)
{
status = -1;
break;
}
} while (child != pid);
}
#else
if (__waitpid (pid, &status, 0) != 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;
}
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