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/* Subprocesses with pipes.
Copyright (C) 2002, 2004, 2005, 2006 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Paul Eggert <eggert@twinsun.com>
and Florian Krohm <florian@edamail.fishkill.ibm.com>. */
#include <config.h>
#include "subpipe.h"
#include <errno.h>
#include <signal.h>
#if ! defined SIGCHLD && defined SIGCLD
# define SIGCHLD SIGCLD
#endif
#include <stdlib.h>
#include <unistd.h>
#ifndef STDIN_FILENO
# define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
# define STDOUT_FILENO 1
#endif
#if ! HAVE_DUP2 && ! defined dup2
# include <fcntl.h>
# define dup2(f, t) (close (t), fcntl (f, F_DUPFD, t))
#endif
#if HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif
#ifndef WEXITSTATUS
# define WEXITSTATUS(stat_val) ((unsigned int) (stat_val) >> 8)
#endif
#ifndef WIFEXITED
# define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
#endif
#if HAVE_VFORK_H
# include <vfork.h>
#endif
#if ! HAVE_WORKING_VFORK
# define vfork fork
#endif
#include "error.h"
#include "unistd-safer.h"
#include "gettext.h"
#define _(Msgid) gettext (Msgid)
#ifndef __attribute__
/* This feature is available in gcc versions 2.5 and later. */
# if ! defined __GNUC__ || __GNUC__ < 2 || \
(__GNUC__ == 2 && __GNUC_MINOR__ < 5) || __STRICT_ANSI__
# define __attribute__(Spec) /* empty */
# endif
#endif
#ifndef ATTRIBUTE_UNUSED
# define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
#endif
/* Initialize this module. */
void
init_subpipe (void)
{
#ifdef SIGCHLD
/* System V fork+wait does not work if SIGCHLD is ignored. */
signal (SIGCHLD, SIG_DFL);
#endif
}
/* Create a subprocess that is run as a filter. ARGV is the
NULL-terminated argument vector for the subprocess. Store read and
write file descriptors for communication with the subprocess into
FD[0] and FD[1]: input meant for the process can be written into
FD[0], and output from the process can be read from FD[1]. Return
the subprocess id.
To avoid deadlock, the invoker must not let incoming data pile up
in FD[1] while writing data to FD[0]. */
pid_t
create_subpipe (char const * const *argv, int fd[2])
{
int pipe_fd[2];
int child_fd[2];
pid_t pid;
if (pipe_safer (child_fd) != 0 || pipe_safer (pipe_fd) != 0)
error (EXIT_FAILURE, errno, "pipe");
fd[0] = child_fd[1];
fd[1] = pipe_fd[0];
child_fd[1] = pipe_fd[1];
pid = vfork ();
if (pid < 0)
error (EXIT_FAILURE, errno, "fork");
if (! pid)
{
/* Child. */
close (fd[0]);
close (fd[1]);
dup2 (child_fd[0], STDIN_FILENO);
close (child_fd[0]);
dup2 (child_fd[1], STDOUT_FILENO);
close (child_fd[1]);
/* The cast to (char **) rather than (char * const *) is needed
for portability to older hosts with a nonstandard prototype
for execvp. */
execvp (argv[0], (char **) argv);
_exit (errno == ENOENT ? 127 : 126);
}
/* Parent. */
close (child_fd[0]);
close (child_fd[1]);
return pid;
}
/* Wait for the subprocess to exit. */
void
reap_subpipe (pid_t pid, char const *program)
{
#if HAVE_WAITPID || defined waitpid
int wstatus;
if (waitpid (pid, &wstatus, 0) < 0)
error (EXIT_FAILURE, errno, "waitpid");
else
{
int status = WIFEXITED (wstatus) ? WEXITSTATUS (wstatus) : -1;
if (status)
error (EXIT_FAILURE, 0,
_(status == 126
? "subsidiary program `%s' could not be invoked"
: status == 127
? "subsidiary program `%s' not found"
: status < 0
? "subsidiary program `%s' failed"
: "subsidiary program `%s' failed (exit status %d)"),
program, status);
}
#endif
}
void
end_of_output_subpipe (pid_t pid ATTRIBUTE_UNUSED,
int fd[2] ATTRIBUTE_UNUSED)
{
}
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