gsasl  1.10.0
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dup2.c
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1 /* Duplicate an open file descriptor to a specified file descriptor.
2 
3  Copyright (C) 1999, 2004-2007, 2009-2021 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 <https://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 #undef dup2
29 
30 #if defined _WIN32 && ! defined __CYGWIN__
31 
32 /* Get declarations of the native Windows API functions. */
33 # define WIN32_LEAN_AND_MEAN
34 # include <windows.h>
35 
36 # if HAVE_MSVC_INVALID_PARAMETER_HANDLER
37 # include "msvc-inval.h"
38 # endif
39 
40 /* Get _get_osfhandle. */
41 # if GNULIB_MSVC_NOTHROW
42 # include "msvc-nothrow.h"
43 # else
44 # include <io.h>
45 # endif
46 
47 # if HAVE_MSVC_INVALID_PARAMETER_HANDLER
48 static int
49 dup2_nothrow (int fd, int desired_fd)
50 {
51  int result;
52 
54  {
55  result = _dup2 (fd, desired_fd);
56  }
58  {
59  errno = EBADF;
60  result = -1;
61  }
63 
64  return result;
65 }
66 # else
67 # define dup2_nothrow _dup2
68 # endif
69 
70 static int
71 ms_windows_dup2 (int fd, int desired_fd)
72 {
73  int result;
74 
75  /* If fd is closed, mingw hangs on dup2 (fd, fd). If fd is open,
76  dup2 (fd, fd) returns 0, but all further attempts to use fd in
77  future dup2 calls will hang. */
78  if (fd == desired_fd)
79  {
80  if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
81  {
82  errno = EBADF;
83  return -1;
84  }
85  return fd;
86  }
87 
88  /* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
89  https://bugs.winehq.org/show_bug.cgi?id=21289 */
90  if (desired_fd < 0)
91  {
92  errno = EBADF;
93  return -1;
94  }
95 
96  result = dup2_nothrow (fd, desired_fd);
97 
98  if (result == 0)
99  result = desired_fd;
100 
101  return result;
102 }
103 
104 # define dup2 ms_windows_dup2
105 
106 #elif defined __KLIBC__
107 
108 # include <InnoTekLIBC/backend.h>
109 
110 static int
111 klibc_dup2dirfd (int fd, int desired_fd)
112 {
113  int tempfd;
114  int dupfd;
115 
116  tempfd = open ("NUL", O_RDONLY);
117  if (tempfd == -1)
118  return -1;
119 
120  if (tempfd == desired_fd)
121  {
122  close (tempfd);
123 
124  char path[_MAX_PATH];
125  if (__libc_Back_ioFHToPath (fd, path, sizeof (path)))
126  return -1;
127 
128  return open(path, O_RDONLY);
129  }
130 
131  dupfd = klibc_dup2dirfd (fd, desired_fd);
132 
133  close (tempfd);
134 
135  return dupfd;
136 }
137 
138 static int
139 klibc_dup2 (int fd, int desired_fd)
140 {
141  int dupfd;
142  struct stat sbuf;
143 
144  dupfd = dup2 (fd, desired_fd);
145  if (dupfd == -1 && errno == ENOTSUP \
146  && !fstat (fd, &sbuf) && S_ISDIR (sbuf.st_mode))
147  {
148  close (desired_fd);
149 
150  return klibc_dup2dirfd (fd, desired_fd);
151  }
152 
153  return dupfd;
154 }
155 
156 # define dup2 klibc_dup2
157 #endif
158 
159 int
160 rpl_dup2 (int fd, int desired_fd)
161 {
162  int result;
163 
164 #ifdef F_GETFL
165  /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
166  On Cygwin 1.5.x, dup2 (1, 1) returns 0.
167  On Cygwin 1.7.17, dup2 (1, -1) dumps core.
168  On Cygwin 1.7.25, dup2 (1, 256) can dump core.
169  On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC. */
170 # if HAVE_SETDTABLESIZE
171  setdtablesize (desired_fd + 1);
172 # endif
173  if (desired_fd < 0)
174  fd = desired_fd;
175  if (fd == desired_fd)
176  return fcntl (fd, F_GETFL) == -1 ? -1 : fd;
177 #endif
178 
179  result = dup2 (fd, desired_fd);
180 
181  /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x. */
182  if (result == -1 && errno == EMFILE)
183  errno = EBADF;
184 #if REPLACE_FCHDIR
185  if (fd != desired_fd && result != -1)
186  result = _gl_register_dup (fd, result);
187 #endif
188  return result;
189 }
int rpl_dup2(int fd, int desired_fd)
Definition: dup2.c:160
#define ENOTSUP
Definition: errno.in.h:213
int fcntl(int fd, int action,...)
Definition: fcntl.c:202
#define CATCH_MSVC_INVAL
Definition: msvc-inval.h:214
#define DONE_MSVC_INVAL
Definition: msvc-inval.h:216
#define TRY_MSVC_INVAL
Definition: msvc-inval.h:210
int open(const char *filename, int flags,...)
Definition: open.c:59
#define S_ISDIR(m)
Definition: sys_stat.in.h:195