1 /* Duplicate an open file descriptor to a specified file descriptor.
3 Copyright (C) 1999, 2004-2007, 2009-2013 Free Software Foundation, Inc.
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.
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.
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/>. */
18 /* written by Paul Eggert */
32 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
34 /* Get declarations of the native Windows API functions. */
35 # define WIN32_LEAN_AND_MEAN
38 # include "msvc-inval.h"
40 /* Get _get_osfhandle. */
41 # include "msvc-nothrow.h"
44 ms_windows_dup2 (int fd, int desired_fd)
48 /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open,
49 dup2 (fd, fd) returns 0, but all further attempts to use fd in
50 future dup2 calls will hang. */
53 if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
61 /* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
62 http://bugs.winehq.org/show_bug.cgi?id=21289 */
71 result = dup2 (fd, desired_fd);
86 # define dup2 ms_windows_dup2
91 rpl_dup2 (int fd, int desired_fd)
96 /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
97 On Cygwin 1.5.x, dup2 (1, 1) returns 0.
98 On Cygwin 1.7.17, dup2 (1, -1) dumps core.
99 On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */
102 if (fd == desired_fd)
103 return fcntl (fd, F_GETFL) == -1 ? -1 : fd;
106 result = dup2 (fd, desired_fd);
108 /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */
109 if (result == -1 && errno == EMFILE)
112 if (fd != desired_fd && result != -1)
113 result = _gl_register_dup (fd, result);
118 #else /* !HAVE_DUP2 */
120 /* On older platforms, dup2 did not exist. */
124 dupfd (int fd, int desired_fd)
126 int duplicated_fd = dup (fd);
127 if (duplicated_fd < 0 || duplicated_fd == desired_fd)
128 return duplicated_fd;
131 int r = dupfd (fd, desired_fd);
133 close (duplicated_fd);
141 dup2 (int fd, int desired_fd)
143 int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd;
144 if (result == -1 || fd == desired_fd)
148 result = fcntl (fd, F_DUPFD, desired_fd);
151 result = _gl_register_dup (fd, result);
154 result = dupfd (fd, desired_fd);
156 if (result == -1 && (errno == EMFILE || errno == EINVAL))
160 #endif /* !HAVE_DUP2 */