/* Invoke pipe, but avoid some glitches.

   Copyright (C) 2005-2006, 2009-2017 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 Jim Meyering.  */

#include <config.h>

#include "unistd-safer.h"

#include <unistd.h>

#include <errno.h>

/* Like pipe, but ensure that neither of the file descriptors is

   STDIN_FILENO, STDOUT_FILENO, or STDERR_FILENO.  Fail with ENOSYS on

   platforms that lack pipe.  */

int

pipe_safer (int fd[2])

{

#if HAVE_PIPE

  if (pipe (fd) == 0)

    {

      int i;

      for (i = 0; i < 2; i++)

        {

          fd[i] = fd_safer (fd[i]);

          if (fd[i] < 0)

            {

              int e = errno;

              close (fd[1 - i]);

              errno = e;

              return -1;

            }

        }

      return 0;

    }

#else

  errno = ENOSYS;

#endif

  return -1;

}