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. */
23 #include "signature.h"
24 SIGNATURE_CHECK (dup2, int, (int, int));
29 #include "binary-io.h"
32 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
33 /* Get declarations of the Win32 API functions. */
34 # define WIN32_LEAN_AND_MEAN
40 /* Return non-zero if FD is open. */
44 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
45 /* On Win32, the initial state of unassigned standard file
46 descriptors is that they are open but point to an
47 INVALID_HANDLE_VALUE, and there is no fcntl. */
48 return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
51 # error Please port fcntl to your platform
53 return 0 <= fcntl (fd, F_GETFL);
57 /* Return non-zero if FD is open and inheritable across exec/spawn. */
59 is_inheritable (int fd)
61 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
62 /* On Win32, the initial state of unassigned standard file
63 descriptors is that they are open but point to an
64 INVALID_HANDLE_VALUE, and there is no fcntl. */
65 HANDLE h = (HANDLE) _get_osfhandle (fd);
67 if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
69 return (flags & HANDLE_FLAG_INHERIT) != 0;
72 # error Please port fcntl to your platform
74 int i = fcntl (fd, F_GETFD);
75 return 0 <= i && (i & FD_CLOEXEC) == 0;
80 # define setmode(f,m) zero ()
81 static int zero (void) { return 0; }
84 /* Return non-zero if FD is open in the given MODE, which is either
85 O_TEXT or O_BINARY. */
87 is_mode (int fd, int mode)
89 int value = setmode (fd, O_BINARY);
97 const char *file = "test-dup2.tmp";
99 int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600);
101 /* Assume std descriptors were provided by invoker. */
102 ASSERT (STDERR_FILENO < fd);
103 ASSERT (is_open (fd));
104 /* Ignore any other fd's leaked into this process. */
107 ASSERT (!is_open (fd + 1));
108 ASSERT (!is_open (fd + 2));
110 /* Assigning to self must be a no-op. */
111 ASSERT (dup2 (fd, fd) == fd);
112 ASSERT (is_open (fd));
114 /* The source must be valid. */
116 ASSERT (dup2 (-1, fd) == -1);
117 ASSERT (errno == EBADF);
119 ASSERT (dup2 (AT_FDCWD, fd) == -1);
120 ASSERT (errno == EBADF);
121 ASSERT (is_open (fd));
123 /* If the source is not open, then the destination is unaffected. */
125 ASSERT (dup2 (fd + 1, fd + 1) == -1);
126 ASSERT (errno == EBADF);
127 ASSERT (!is_open (fd + 1));
129 ASSERT (dup2 (fd + 1, fd) == -1);
130 ASSERT (errno == EBADF);
131 ASSERT (is_open (fd));
133 /* The destination must be valid. */
135 ASSERT (dup2 (fd, -2) == -1);
136 ASSERT (errno == EBADF);
138 ASSERT (dup2 (fd, 10000000) == -1);
139 ASSERT (errno == EBADF);
141 /* Using dup2 can skip fds. */
142 ASSERT (dup2 (fd, fd + 2) == fd + 2);
143 ASSERT (is_open (fd));
144 ASSERT (!is_open (fd + 1));
145 ASSERT (is_open (fd + 2));
147 /* Verify that dup2 closes the previous occupant of a fd. */
148 ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
149 ASSERT (dup2 (fd + 1, fd) == fd);
150 ASSERT (close (fd + 1) == 0);
151 ASSERT (write (fd, "1", 1) == 1);
152 ASSERT (dup2 (fd + 2, fd) == fd);
153 ASSERT (lseek (fd, 0, SEEK_END) == 0);
154 ASSERT (write (fd + 2, "2", 1) == 1);
155 ASSERT (lseek (fd, 0, SEEK_SET) == 0);
156 ASSERT (read (fd, buffer, 1) == 1);
157 ASSERT (*buffer == '2');
159 /* Any new fd created by dup2 must not be cloexec. */
160 ASSERT (close (fd + 2) == 0);
161 ASSERT (dup_cloexec (fd) == fd + 1);
162 ASSERT (!is_inheritable (fd + 1));
163 ASSERT (dup2 (fd + 1, fd + 1) == fd + 1);
164 ASSERT (!is_inheritable (fd + 1));
165 ASSERT (dup2 (fd + 1, fd + 2) == fd + 2);
166 ASSERT (is_inheritable (fd + 2));
168 /* On systems that distinguish between text and binary mode, dup2
169 reuses the mode of the source. */
170 setmode (fd, O_BINARY);
171 ASSERT (is_mode (fd, O_BINARY));
172 ASSERT (dup2 (fd, fd + 1) == fd + 1);
173 ASSERT (is_mode (fd + 1, O_BINARY));
174 setmode (fd, O_TEXT);
175 ASSERT (is_mode (fd, O_TEXT));
176 ASSERT (dup2 (fd, fd + 1) == fd + 1);
177 ASSERT (is_mode (fd + 1, O_TEXT));
180 ASSERT (close (fd + 2) == 0);
181 ASSERT (close (fd + 1) == 0);
182 ASSERT (close (fd) == 0);
183 ASSERT (unlink (file) == 0);