gl/dup-safer.c

   1 /* Invoke dup, but avoid some glitches.
   2
   3    Copyright (C) 2001, 2004, 2005, 2006, 2009 Free Software
   4    Foundation, Inc.
   5
   6    This program is free software: you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 /* Written by Paul Eggert.  */
  20
  21 #include <config.h>
  22
  23 #include "unistd-safer.h"
  24
  25 #include <fcntl.h>
  26
  27 #include <unistd.h>
  28
  29 /* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
  30    STDERR_FILENO.  */
  31
  32 int
  33 dup_safer (int fd)
  34 {
  35 #if defined F_DUPFD && !defined FCHDIR_REPLACEMENT
  36   return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
  37 #else
  38   /* fd_safer calls us back, but eventually the recursion unwinds and
  39      does the right thing.  */
  40   return fd_safer (dup (fd));
  41 #endif
  42 }