1 /* Test duplicating file descriptors.
2 Copyright (C) 2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by Eric Blake <ebb9@byu.net>, 2009,
18 and Bruno Haible <bruno@clisp.org>, 2009. */
24 #include "signature.h"
25 SIGNATURE_CHECK (dup3, int, (int, int, int));
33 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
34 /* Get declarations of the Win32 API functions. */
35 # define WIN32_LEAN_AND_MEAN
39 #include "binary-io.h"
41 #define ASSERT(expr) \
46 fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
53 /* Return true if FD is open. */
57 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
58 /* On Win32, the initial state of unassigned standard file
59 descriptors is that they are open but point to an
60 INVALID_HANDLE_VALUE, and there is no fcntl. */
61 return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
64 # error Please port fcntl to your platform
66 return 0 <= fcntl (fd, F_GETFL);
70 /* Return true if FD is not inherited to child processes. */
74 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
75 HANDLE h = (HANDLE) _get_osfhandle (fd);
77 ASSERT (GetHandleInformation (h, &flags));
78 return (flags & HANDLE_FLAG_INHERIT) == 0;
81 ASSERT ((flags = fcntl (fd, F_GETFD)) >= 0);
82 return (flags & FD_CLOEXEC) != 0;
92 for (use_cloexec = 0; use_cloexec <= 1; use_cloexec++)
97 const char *file = "test-dup3.tmp";
98 int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600);
103 #if defined O_CLOEXEC
105 o_flags |= O_CLOEXEC;
108 /* Assume std descriptors were provided by invoker. */
109 ASSERT (STDERR_FILENO < fd);
110 ASSERT (is_open (fd));
111 /* Ignore any other fd's leaked into this process. */
114 ASSERT (!is_open (fd + 1));
115 ASSERT (!is_open (fd + 2));
117 /* Assigning to self is invalid. */
119 ASSERT (dup3 (fd, fd, o_flags) == -1);
120 ASSERT (errno == EINVAL);
121 ASSERT (is_open (fd));
123 /* If the source is not open, then the destination is unaffected. */
125 ASSERT (dup3 (fd + 1, fd + 2, o_flags) == -1);
126 ASSERT (errno == EBADF);
127 ASSERT (!is_open (fd + 2));
129 ASSERT (dup3 (fd + 1, fd, o_flags) == -1);
130 ASSERT (errno == EBADF);
131 ASSERT (is_open (fd));
133 /* The destination must be valid. */
135 ASSERT (dup3 (fd, -2, o_flags) == -1);
136 ASSERT (errno == EBADF);
138 ASSERT (dup3 (fd, 10000000, o_flags) == -1);
139 ASSERT (errno == EBADF);
141 /* Using dup3 can skip fds. */
142 ASSERT (dup3 (fd, fd + 2, o_flags) == fd + 2);
143 ASSERT (is_open (fd));
144 ASSERT (!is_open (fd + 1));
145 ASSERT (is_open (fd + 2));
147 ASSERT (is_cloexec (fd + 2));
149 ASSERT (!is_cloexec (fd + 2));
151 /* Verify that dup3 closes the previous occupant of a fd. */
152 ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
153 ASSERT (dup3 (fd + 1, fd, o_flags) == fd);
154 ASSERT (close (fd + 1) == 0);
155 ASSERT (write (fd, "1", 1) == 1);
156 ASSERT (dup3 (fd + 2, fd, o_flags) == fd);
157 ASSERT (lseek (fd, 0, SEEK_END) == 0);
158 ASSERT (write (fd + 2, "2", 1) == 1);
159 ASSERT (lseek (fd, 0, SEEK_SET) == 0);
160 ASSERT (read (fd, buffer, 1) == 1);
161 ASSERT (*buffer == '2');
164 ASSERT (close (fd + 2) == 0);
165 ASSERT (close (fd) == 0);
166 ASSERT (unlink (file) == 0);