159 lines
4.0 KiB
C
159 lines
4.0 KiB
C
/* Copyright (C) 1991-1999, 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <stddef.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/wait.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <errno.h>
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#include <machine/weakalias.h>
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#ifndef HAVE_GNU_LD
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#define __environ environ
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#endif
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#define SHELL_PATH "/bin/sh" /* Path of the shell. */
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#define SHELL_NAME "sh" /* Name to give it. */
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/* Execute LINE as a shell command, returning its status. */
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int
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__libc_system (const char *line)
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{
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int status, save;
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pid_t pid;
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struct sigaction sa, intr, quit;
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#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD
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sigset_t block, omask;
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#endif
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if (line == NULL)
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/* Check that we have a command processor available. It might
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not be available after a chroot(), for example. */
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return __libc_system ("exit 0") == 0;
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sa.sa_handler = SIG_IGN;
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sa.sa_flags = 0;
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sigemptyset (&sa.sa_mask);
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if (sigaction (SIGINT, &sa, &intr) < 0)
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return -1;
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if (sigaction (SIGQUIT, &sa, &quit) < 0)
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{
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save = errno;
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(void) sigaction (SIGINT, &intr, (struct sigaction *) NULL);
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errno = save;
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return -1;
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}
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#ifndef WAITPID_CANNOT_BLOCK_SIGCHLD
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/* SCO 3.2v4 has a bug where `waitpid' will never return if SIGCHLD is
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blocked. This makes it impossible for `system' to be implemented in
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compliance with POSIX.2-1992. They have acknowledged that this is a bug
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but I have not seen nor heard of any forthcoming fix. */
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sigemptyset (&block);
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sigaddset (&block, SIGCHLD);
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save = errno;
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if (sigprocmask (SIG_BLOCK, &block, &omask) < 0)
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{
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if (errno == ENOSYS)
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errno = save;
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else
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{
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save = errno;
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(void) sigaction (SIGINT, &intr, (struct sigaction *) NULL);
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(void) sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
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errno = save;
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return -1;
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}
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}
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# define UNBLOCK sigprocmask (SIG_SETMASK, &omask, (sigset_t *) NULL)
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#else
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# define UNBLOCK 0
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#endif
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pid = fork ();
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if (pid == (pid_t) 0)
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{
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/* Child side. */
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const char *new_argv[4];
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new_argv[0] = SHELL_NAME;
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new_argv[1] = "-c";
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new_argv[2] = line;
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new_argv[3] = NULL;
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/* Restore the signals. */
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(void) sigaction (SIGINT, &intr, (struct sigaction *) NULL);
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(void) sigaction (SIGQUIT, &quit, (struct sigaction *) NULL);
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(void) UNBLOCK;
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/* Exec the shell. */
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(void) execve (SHELL_PATH, (char *const *) new_argv, __environ);
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_exit (127);
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}
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else if (pid < (pid_t) 0)
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/* The fork failed. */
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status = -1;
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else
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/* Parent side. */
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{
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#ifdef NO_WAITPID
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pid_t child;
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do
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{
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child = wait (&status);
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if (child <= -1 && errno != EINTR)
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{
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status = -1;
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break;
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}
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/* Note that pid cannot be <= -1 and therefore the loop continues
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when wait returned with EINTR. */
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}
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while (child != pid);
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#else
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int n;
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do
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n = waitpid (pid, &status, 0);
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while (n == -1 && errno == EINTR);
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if (n != pid)
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status = -1;
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#endif
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}
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save = errno;
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if ((sigaction (SIGINT, &intr, (struct sigaction *) NULL) |
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sigaction (SIGQUIT, &quit, (struct sigaction *) NULL) |
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UNBLOCK) != 0)
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{
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if (errno == ENOSYS)
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errno = save;
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else
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return -1;
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}
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return status;
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}
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weak_alias (__libc_system, system)
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