1 /* Duplicate an open file descriptor to a specified file descriptor.
3 Copyright (C) 1999, 2004-2007, 2009-2017 Free Software Foundation,
6 This program is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19 /* written by Paul Eggert */
33 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
35 /* Get declarations of the native Windows API functions. */
36 # define WIN32_LEAN_AND_MEAN
39 # include "msvc-inval.h"
41 /* Get _get_osfhandle. */
42 # include "msvc-nothrow.h"
45 ms_windows_dup2 (int fd
, int desired_fd
)
49 /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open,
50 dup2 (fd, fd) returns 0, but all further attempts to use fd in
51 future dup2 calls will hang. */
54 if ((HANDLE
) _get_osfhandle (fd
) == INVALID_HANDLE_VALUE
)
62 /* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
63 http://bugs.winehq.org/show_bug.cgi?id=21289 */
72 result
= dup2 (fd
, desired_fd
);
87 # define dup2 ms_windows_dup2
89 # elif defined __KLIBC__
91 # include <InnoTekLIBC/backend.h>
94 klibc_dup2dirfd (int fd
, int desired_fd
)
99 tempfd
= open ("NUL", O_RDONLY
);
103 if (tempfd
== desired_fd
)
107 char path
[_MAX_PATH
];
108 if (__libc_Back_ioFHToPath (fd
, path
, sizeof (path
)))
111 return open(path
, O_RDONLY
);
114 dupfd
= klibc_dup2dirfd (fd
, desired_fd
);
122 klibc_dup2 (int fd
, int desired_fd
)
127 dupfd
= dup2 (fd
, desired_fd
);
128 if (dupfd
== -1 && errno
== ENOTSUP \
129 && !fstat (fd
, &sbuf
) && S_ISDIR (sbuf
.st_mode
))
133 return klibc_dup2dirfd (fd
, desired_fd
);
139 # define dup2 klibc_dup2
143 rpl_dup2 (int fd
, int desired_fd
)
148 /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
149 On Cygwin 1.5.x, dup2 (1, 1) returns 0.
150 On Cygwin 1.7.17, dup2 (1, -1) dumps core.
151 On Cygwin 1.7.25, dup2 (1, 256) can dump core.
152 On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */
153 # if HAVE_SETDTABLESIZE
154 setdtablesize (desired_fd
+ 1);
158 if (fd
== desired_fd
)
159 return fcntl (fd
, F_GETFL
) == -1 ? -1 : fd
;
162 result
= dup2 (fd
, desired_fd
);
164 /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */
165 if (result
== -1 && errno
== EMFILE
)
168 if (fd
!= desired_fd
&& result
!= -1)
169 result
= _gl_register_dup (fd
, result
);
174 #else /* !HAVE_DUP2 */
176 /* On older platforms, dup2 did not exist. */
180 dupfd (int fd
, int desired_fd
)
182 int duplicated_fd
= dup (fd
);
183 if (duplicated_fd
< 0 || duplicated_fd
== desired_fd
)
184 return duplicated_fd
;
187 int r
= dupfd (fd
, desired_fd
);
189 close (duplicated_fd
);
197 dup2 (int fd
, int desired_fd
)
199 int result
= fcntl (fd
, F_GETFL
) < 0 ? -1 : fd
;
200 if (result
== -1 || fd
== desired_fd
)
204 result
= fcntl (fd
, F_DUPFD
, desired_fd
);
207 result
= _gl_register_dup (fd
, result
);
210 result
= dupfd (fd
, desired_fd
);
212 if (result
== -1 && (errno
== EMFILE
|| errno
== EINVAL
))
216 #endif /* !HAVE_DUP2 */