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glibc/sysdeps/posix/system.c
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/* Copyright (C) 1991-99,2000,02 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 <errno.h> | |
#include <signal.h> | |
#include <stddef.h> | |
#include <stdlib.h> | |
#include <unistd.h> | |
#include <sys/types.h> | |
#include <sys/wait.h> | |
#include <bits/libc-lock.h> | |
#include <sysdep-cancel.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. */ | |
#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() (void) 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 | |
#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD | |
sigset_t block, omask; | |
#endif | |
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) | |
{ | |
SUB_REF (); | |
DO_UNLOCK (); | |
return -1; | |
} | |
if (__sigaction (SIGQUIT, &sa, &quit) < 0) | |
{ | |
save = errno; | |
goto out_restore_sigint; | |
} | |
} | |
DO_UNLOCK (); | |
__sigemptyset (&block); | |
__sigaddset (&block, SIGCHLD); | |
save = errno; | |
if (__sigprocmask (SIG_BLOCK, &block, &omask) < 0) | |
{ | |
if (errno == ENOSYS) | |
__set_errno (save); | |
else | |
{ | |
save = errno; | |
DO_LOCK (); | |
if (SUB_REF () == 0) | |
{ | |
(void) __sigaction (SIGQUIT, &quit, (struct sigaction *) NULL); | |
out_restore_sigint: | |
(void) __sigaction (SIGINT, &intr, (struct sigaction *) NULL); | |
} | |
DO_UNLOCK (); | |
__set_errno (save); | |
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. */ | |
{ | |
#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 | |
if (TEMP_FAILURE_RETRY (__waitpid (pid, &status, 0)) != pid) | |
status = -1; | |
#endif | |
} | |
#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; | |
if (SINGLE_THREAD_P) | |
return do_system (line); | |
int oldtype = LIBC_CANCEL_ASYNC (); | |
int result = do_system (line); | |
LIBC_CANCEL_RESET (oldtype); | |
return result; | |
} | |
weak_alias (__libc_system, system) |