lib/pipe2-safer.c

   1 /* Invoke pipe2, but avoid some glitches.
   2    Copyright (C) 2005-2006, 2009-2019 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 }