1/* Invoke dup, but avoid some glitches.
2   Copyright (C) 2001, 2004 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
17
18/* Written by Paul Eggert.  */
19
20#if HAVE_CONFIG_H
21# include <config.h>
22#endif
23
24#include <errno.h>
25
26#if HAVE_FCNTL_H
27# include <fcntl.h>
28#endif
29
30#if HAVE_UNISTD_H
31# include <unistd.h>
32#endif
33#ifndef STDERR_FILENO
34# define STDERR_FILENO 2
35#endif
36
37#include <unistd-safer.h>
38
39/* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
40   STDERR_FILENO.  */
41
42int
43dup_safer (int fd)
44{
45#ifdef F_DUPFD
46  return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
47#else
48  int f = dup (fd);
49  if (0 <= f && f <= STDERR_FILENO)
50    {
51      int f1 = dup_safer (f);
52      int e = errno;
53      close (f);
54      errno = e;
55      f = f1;
56    }
57  return f;
58#endif
59}
60