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/* Creation of subprocesses, communicating via pipes.
Copyright (C) 2001 Free Software Foundation, Inc.
Written by Bruno Haible <haible@clisp.cons.org>, 2001.
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 2, 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, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_POSIX_SPAWN
# include <spawn.h>
#else
# ifdef HAVE_VFORK_H
# include <vfork.h>
# endif
#endif
#include "error.h"
#include "libgettext.h"
#ifndef STDIN_FILENO
# define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
# define STDOUT_FILENO 1
#endif
#define _(str) gettext (str)
#ifdef EINTR
/* EINTR handling for close(), open().
These functions can return -1/EINTR even though we don't have any
signal handlers set up, namely when we get interrupted via SIGSTOP. */
static inline int
nonintr_close (fd)
int fd;
{
int retval;
do
retval = close (fd);
while (retval < 0 && errno == EINTR);
return retval;
}
#define close nonintr_close
static inline int
nonintr_open (pathname, oflag, mode)
const char *pathname;
int oflag;
mode_t mode;
{
int retval;
do
retval = open (pathname, oflag, mode);
while (retval < 0 && errno == EINTR);
return retval;
}
#define open nonintr_open
#endif
/* Open a pipe for output to a child process.
* The child's stdout goes to a file.
*
* write system read
* parent -> fd[0] -> STDIN_FILENO -> child
*
*/
pid_t
create_pipe_out (progname, prog_path, prog_argv, prog_stdout, fd)
const char *progname;
const char *prog_path;
char **prog_argv;
const char *prog_stdout;
int fd[1];
{
int ofd[2];
#if HAVE_POSIX_SPAWN
posix_spawn_file_actions_t actions;
int err;
pid_t child;
#else
int child;
#endif
if (pipe (ofd) < 0)
error (EXIT_FAILURE, errno, _("cannot create pipe"));
/* Data flow diagram:
*
* write system read
* parent -> ofd[1] -> ofd[0] -> child
*/
#if HAVE_POSIX_SPAWN
if ((err = posix_spawn_file_actions_init (&actions)) != 0
|| (err = posix_spawn_file_actions_adddup2 (&actions,
ofd[0], STDIN_FILENO)) != 0
|| (err = posix_spawn_file_actions_addclose (&actions, ofd[0])) != 0
|| (err = posix_spawn_file_actions_addclose (&actions, ofd[1])) != 0
|| (err = posix_spawn_file_actions_addopen (&actions, STDOUT_FILENO,
prog_stdout, O_WRONLY,
0)) != 0
|| (err = posix_spawnp (&child, prog_path, &actions, NULL, prog_argv,
environ)) != 0)
error (EXIT_FAILURE, err, _("%s subprocess failed"), progname);
posix_spawn_file_actions_destroy (&actions);
#else
/* Use vfork() instead of fork() for efficiency. */
if ((child = vfork ()) == 0)
{
/* Child process code. */
int stdoutfd;
if (dup2 (ofd[0], STDIN_FILENO) >= 0
&& close (ofd[0]) >= 0
&& close (ofd[1]) >= 0
&& (stdoutfd = open (prog_stdout, O_WRONLY, 0)) >= 0
&& (stdoutfd == STDOUT_FILENO
|| (dup2 (stdoutfd, STDOUT_FILENO) >= 0
&& close (stdoutfd) >= 0)))
execvp (prog_path, prog_argv);
_exit (-1);
}
if (child == -1)
error (EXIT_FAILURE, errno, _("%s subprocess failed"), progname);
#endif
close (ofd[0]);
fd[0] = ofd[1];
return child;
}
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