1  /* Invoke pipe2, but avoid some glitches.
       2     Copyright (C) 2005-2006, 2009-2021 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation; either version 3 of the License, or
       7     (at your option) any later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* Written by Eric Blake.  */
      18  
      19  #include <config.h>
      20  
      21  /* Specification.  */
      22  #include "unistd-safer.h"
      23  
      24  #include <unistd.h>
      25  #include <errno.h>
      26  
      27  /* Like pipe2, but ensure that neither of the file descriptors is
      28     STDIN_FILENO, STDOUT_FILENO, or STDERR_FILENO.  */
      29  
      30  int
      31  pipe2_safer (int fd[2], int flags)
      32  {
      33    /* This is a generalization of the pipe_safer implementation.  */
      34    if (pipe2 (fd, flags) == 0)
      35      {
      36        int i;
      37        for (i = 0; i < 2; i++)
      38          {
      39            fd[i] = fd_safer_flag (fd[i], flags);
      40            if (fd[i] < 0)
      41              {
      42                int e = errno;
      43                close (fd[1 - i]);
      44                errno = e;
      45                return -1;
      46              }
      47          }
      48  
      49        return 0;
      50      }
      51    return -1;
      52  }