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 3 of the License, or
8   (at your option) 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, see <http://www.gnu.org/licenses/>.  */
17
18/* Written by Paul Eggert.  */
19
20#include <config.h>
21
22#include "unistd-safer.h"
23
24#include <fcntl.h>
25
26#include <unistd.h>
27#ifndef STDERR_FILENO
28# define STDERR_FILENO 2
29#endif
30
31/* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
32   STDERR_FILENO.  */
33
34int
35dup_safer (int fd)
36{
37#if defined F_DUPFD && !defined FCHDIR_REPLACEMENT
38  return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
39#else
40  /* fd_safer calls us back, but eventually the recursion unwinds and
41     does the right thing.  */
42  return fd_safer (dup (fd));
43#endif
44}
45