contrib/cvs-1.12/lib/dup-safer.c

   1 /* Invoke dup, but avoid some glitches.
   2    Copyright (C) 2001, 2004, 2005 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 2, or (at your option)
   7    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, write to the Free Software Foundation,
  16    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include "unistd-safer.h"
  25
  26 #include <fcntl.h>
  27
  28 #include <unistd.h>
  29 #ifndef STDERR_FILENO
  30 # define STDERR_FILENO 2
  31 #endif
  32
  33 /* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
  34    STDERR_FILENO.  */
  35
  36 int
  37 dup_safer (int fd)
  38 {
  39 #ifdef F_DUPFD
  40   return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
  41 #else
  42   /* fd_safer calls us back, but eventually the recursion unwinds and
  43      does the right thing.  */
  44   return fd_safer (dup (fd));
  45 #endif
  46 }