1: /* Invoke dup, but avoid some glitches.
    2: 
    3:    Copyright (C) 2001, 2004, 2005, 2006 Free Software Foundation, Inc.
    4: 
    5:    This program is free software; you can redistribute it and/or modify
    6:    it under the terms of the GNU General Public License as published by
    7:    the Free Software Foundation; either version 2, or (at your option)
    8:    any later version.
    9: 
   10:    This program is distributed in the hope that it will be useful,
   11:    but WITHOUT ANY WARRANTY; without even the implied warranty of
   12:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   13:    GNU General Public License for more details.
   14: 
   15:    You should have received a copy of the GNU General Public License
   16:    along with this program; if not, write to the Free Software Foundation,
   17:    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
   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: #ifndef STDERR_FILENO
   29: # define STDERR_FILENO 2
   30: #endif
   31: 
   32: /* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
   33:    STDERR_FILENO.  */
   34: 
   35: int
   36: dup_safer (int fd)
   37: {
   38: #if defined F_DUPFD && !defined FCHDIR_REPLACEMENT
   39:   return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
   40: #else
   41:   /* fd_safer calls us back, but eventually the recursion unwinds and
   42:      does the right thing.  */
   43:   return fd_safer (dup (fd));
   44: #endif
   45: }