1 /* Duplicate an open file descriptor to a specified file descriptor.
2
3 Copyright (C) 1999, 2004-2007, 2009-2014 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 /* Specification. */
23 #include <unistd.h>
24
25 #include <errno.h>
26 #include <fcntl.h>
27
28 #if HAVE_DUP2
29
30 # undef dup2
31
32 # if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
33
34 /* Get declarations of the native Windows API functions. */
35 # define WIN32_LEAN_AND_MEAN
36 # include <windows.h>
37
38 # include "msvc-inval.h"
39
40 /* Get _get_osfhandle. */
41 # include "msvc-nothrow.h"
42
43 static int
ms_windows_dup2(int fd,int desired_fd)44 ms_windows_dup2 (int fd, int desired_fd)
45 {
46 int result;
47
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. */
51 if (fd == desired_fd)
52 {
53 if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
54 {
55 errno = EBADF;
56 return -1;
57 }
58 return fd;
59 }
60
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 */
63 if (desired_fd < 0)
64 {
65 errno = EBADF;
66 return -1;
67 }
68
69 TRY_MSVC_INVAL
70 {
71 result = dup2 (fd, desired_fd);
72 }
73 CATCH_MSVC_INVAL
74 {
75 errno = EBADF;
76 result = -1;
77 }
78 DONE_MSVC_INVAL;
79
80 if (result == 0)
81 result = desired_fd;
82
83 return result;
84 }
85
86 # define dup2 ms_windows_dup2
87
88 # endif
89
90 int
rpl_dup2(int fd,int desired_fd)91 rpl_dup2 (int fd, int desired_fd)
92 {
93 int result;
94
95 # ifdef F_GETFL
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 Cygwin 1.7.25, dup2 (1, 256) can dump core.
100 On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */
101 # if HAVE_SETDTABLESIZE
102 setdtablesize (desired_fd + 1);
103 # endif
104 if (desired_fd < 0)
105 fd = desired_fd;
106 if (fd == desired_fd)
107 return fcntl (fd, F_GETFL) == -1 ? -1 : fd;
108 # endif
109
110 result = dup2 (fd, desired_fd);
111
112 /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */
113 if (result == -1 && errno == EMFILE)
114 errno = EBADF;
115 # if REPLACE_FCHDIR
116 if (fd != desired_fd && result != -1)
117 result = _gl_register_dup (fd, result);
118 # endif
119 return result;
120 }
121
122 #else /* !HAVE_DUP2 */
123
124 /* On older platforms, dup2 did not exist. */
125
126 # ifndef F_DUPFD
127 static int
dupfd(int fd,int desired_fd)128 dupfd (int fd, int desired_fd)
129 {
130 int duplicated_fd = dup (fd);
131 if (duplicated_fd < 0 || duplicated_fd == desired_fd)
132 return duplicated_fd;
133 else
134 {
135 int r = dupfd (fd, desired_fd);
136 int e = errno;
137 close (duplicated_fd);
138 errno = e;
139 return r;
140 }
141 }
142 # endif
143
144 int
dup2(int fd,int desired_fd)145 dup2 (int fd, int desired_fd)
146 {
147 int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd;
148 if (result == -1 || fd == desired_fd)
149 return result;
150 close (desired_fd);
151 # ifdef F_DUPFD
152 result = fcntl (fd, F_DUPFD, desired_fd);
153 # if REPLACE_FCHDIR
154 if (0 <= result)
155 result = _gl_register_dup (fd, result);
156 # endif
157 # else
158 result = dupfd (fd, desired_fd);
159 # endif
160 if (result == -1 && (errno == EMFILE || errno == EINVAL))
161 errno = EBADF;
162 return result;
163 }
164 #endif /* !HAVE_DUP2 */
165