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
35int
36dup_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}
46