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/* Copyright (C) 1991-2018 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, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <signal.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <libc-lock.h>
#include <sysdep-cancel.h>
#include <sigsetops.h>
#define SHELL_PATH "/bin/sh" /* Path of the shell. */
#define SHELL_NAME "sh" /* Name to give it. */
#ifdef _LIBC_REENTRANT
static struct sigaction intr, quit;
static int sa_refcntr;
__libc_lock_define_initialized (static, lock);
# define DO_LOCK() __libc_lock_lock (lock)
# define DO_UNLOCK() __libc_lock_unlock (lock)
# define INIT_LOCK() ({ __libc_lock_init (lock); sa_refcntr = 0; })
# define ADD_REF() sa_refcntr++
# define SUB_REF() --sa_refcntr
#else
# define DO_LOCK()
# define DO_UNLOCK()
# define INIT_LOCK()
# define ADD_REF() 0
# define SUB_REF() 0
#endif
/* Execute LINE as a shell command, returning its status. */
static int
do_system (const char *line)
{
int status, save;
pid_t pid;
struct sigaction sa;
#ifndef _LIBC_REENTRANT
struct sigaction intr, quit;
#endif
sigset_t omask;
sa.sa_handler = SIG_IGN;
sa.sa_flags = 0;
__sigemptyset (&sa.sa_mask);
DO_LOCK ();
if (ADD_REF () == 0)
{
if (__sigaction (SIGINT, &sa, &intr) < 0)
{
(void) SUB_REF ();
goto out;
}
if (__sigaction (SIGQUIT, &sa, &quit) < 0)
{
save = errno;
(void) SUB_REF ();
goto out_restore_sigint;
}
}
DO_UNLOCK ();
/* We reuse the bitmap in the 'sa' structure. */
__sigaddset (&sa.sa_mask, SIGCHLD);
save = errno;
if (__sigprocmask (SIG_BLOCK, &sa.sa_mask, &omask) < 0)
{
#ifndef _LIBC
if (errno == ENOSYS)
__set_errno (save);
else
#endif
{
DO_LOCK ();
if (SUB_REF () == 0)
{
save = errno;
(void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
out_restore_sigint:
(void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL);
__set_errno (save);
}
out:
DO_UNLOCK ();
return -1;
}
}
#ifdef CLEANUP_HANDLER
CLEANUP_HANDLER;
#endif
#ifdef FORK
pid = FORK ();
#else
pid = __fork ();
#endif
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) __sigprocmask (SIG_SETMASK, &omask, (sigset_t *) NULL);
INIT_LOCK ();
/* 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. */
{
/* Note the system() is a cancellation point. But since we call
waitpid() which itself is a cancellation point we do not
have to do anything here. */
if (TEMP_FAILURE_RETRY (__waitpid (pid, &status, 0)) != pid)
status = -1;
}
#ifdef CLEANUP_HANDLER
CLEANUP_RESET;
#endif
save = errno;
DO_LOCK ();
if ((SUB_REF () == 0
&& (__sigaction (SIGINT, &intr, (struct sigaction *) NULL)
| __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL)) != 0)
|| __sigprocmask (SIG_SETMASK, &omask, (sigset_t *) NULL) != 0)
{
#ifndef _LIBC
/* glibc cannot be used on systems without waitpid. */
if (errno == ENOSYS)
__set_errno (save);
else
#endif
status = -1;
}
DO_UNLOCK ();
return status;
}
int
__libc_system (const char *line)
{
if (line == NULL)
/* Check that we have a command processor available. It might
not be available after a chroot(), for example. */
return do_system ("exit 0") == 0;
return do_system (line);
}
weak_alias (__libc_system, system)
|
