File: dup2.c

package info (click to toggle)
sharutils 1:4.15.2-4
  • links: PTS
  • area: main
  • in suites: bullseye, buster, sid
  • size: 10,936 kB
  • sloc: ansic: 53,545; sh: 6,933; makefile: 726; yacc: 291; sed: 16
file content (164 lines) | stat: -rw-r--r-- 3,821 bytes parent folder | download | duplicates (17)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
/* Duplicate an open file descriptor to a specified file descriptor.

   Copyright (C) 1999, 2004-2007, 2009-2015 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* written by Paul Eggert */

#include <config.h>

/* Specification.  */
#include <unistd.h>

#include <errno.h>
#include <fcntl.h>

#if HAVE_DUP2

# undef dup2

# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__

/* Get declarations of the native Windows API functions.  */
#  define WIN32_LEAN_AND_MEAN
#  include <windows.h>

#  include "msvc-inval.h"

/* Get _get_osfhandle.  */
#  include "msvc-nothrow.h"

static int
ms_windows_dup2 (int fd, int desired_fd)
{
  int result;

  /* If fd is closed, mingw hangs on dup2 (fd, fd).  If fd is open,
     dup2 (fd, fd) returns 0, but all further attempts to use fd in
     future dup2 calls will hang.  */
  if (fd == desired_fd)
    {
      if ((HANDLE) _get_osfhandle (fd) == INVALID_HANDLE_VALUE)
        {
          errno = EBADF;
          return -1;
        }
      return fd;
    }

  /* Wine 1.0.1 return 0 when desired_fd is negative but not -1:
     http://bugs.winehq.org/show_bug.cgi?id=21289 */
  if (desired_fd < 0)
    {
      errno = EBADF;
      return -1;
    }

  TRY_MSVC_INVAL
    {
      result = dup2 (fd, desired_fd);
    }
  CATCH_MSVC_INVAL
    {
      errno = EBADF;
      result = -1;
    }
  DONE_MSVC_INVAL;

  if (result == 0)
    result = desired_fd;

  return result;
}

#  define dup2 ms_windows_dup2

# endif

int
rpl_dup2 (int fd, int desired_fd)
{
  int result;

# ifdef F_GETFL
  /* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
     On Cygwin 1.5.x, dup2 (1, 1) returns 0.
     On Cygwin 1.7.17, dup2 (1, -1) dumps core.
     On Cygwin 1.7.25, dup2 (1, 256) can dump core.
     On Haiku, dup2 (fd, fd) mistakenly clears FD_CLOEXEC.  */
#  if HAVE_SETDTABLESIZE
  setdtablesize (desired_fd + 1);
#  endif
  if (desired_fd < 0)
    fd = desired_fd;
  if (fd == desired_fd)
    return fcntl (fd, F_GETFL) == -1 ? -1 : fd;
# endif

  result = dup2 (fd, desired_fd);

  /* Correct an errno value on FreeBSD 6.1 and Cygwin 1.5.x.  */
  if (result == -1 && errno == EMFILE)
    errno = EBADF;
# if REPLACE_FCHDIR
  if (fd != desired_fd && result != -1)
    result = _gl_register_dup (fd, result);
# endif
  return result;
}

#else /* !HAVE_DUP2 */

/* On older platforms, dup2 did not exist.  */

# ifndef F_DUPFD
static int
dupfd (int fd, int desired_fd)
{
  int duplicated_fd = dup (fd);
  if (duplicated_fd < 0 || duplicated_fd == desired_fd)
    return duplicated_fd;
  else
    {
      int r = dupfd (fd, desired_fd);
      int e = errno;
      close (duplicated_fd);
      errno = e;
      return r;
    }
}
# endif

int
dup2 (int fd, int desired_fd)
{
  int result = fcntl (fd, F_GETFL) < 0 ? -1 : fd;
  if (result == -1 || fd == desired_fd)
    return result;
  close (desired_fd);
# ifdef F_DUPFD
  result = fcntl (fd, F_DUPFD, desired_fd);
#  if REPLACE_FCHDIR
  if (0 <= result)
    result = _gl_register_dup (fd, result);
#  endif
# else
  result = dupfd (fd, desired_fd);
# endif
  if (result == -1 && (errno == EMFILE || errno == EINVAL))
    errno = EBADF;
  return result;
}
#endif /* !HAVE_DUP2 */