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"
35 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
36 /* Get declarations of the Win32 API functions. */
37 # define WIN32_LEAN_AND_MEAN
43 /* Return non-zero if FD is open. */
47 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
48 /* On Win32, the initial state of unassigned standard file
49 descriptors is that they are open but point to an
50 INVALID_HANDLE_VALUE, and there is no fcntl. */
51 return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
54 # error Please port fcntl to your platform
56 return 0 <= fcntl (fd, F_GETFL);
60 /* Return non-zero if FD is open and inheritable across exec/spawn. */
62 is_inheritable (int fd)
64 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
65 /* On Win32, the initial state of unassigned standard file
66 descriptors is that they are open but point to an
67 INVALID_HANDLE_VALUE, and there is no fcntl. */
68 HANDLE h = (HANDLE) _get_osfhandle (fd);
70 if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
72 return (flags & HANDLE_FLAG_INHERIT) != 0;
75 # error Please port fcntl to your platform
77 int i = fcntl (fd, F_GETFD);
78 return 0 <= i && (i & FD_CLOEXEC) == 0;
83 # define setmode(f,m) zero ()
84 static int zero (void) { return 0; }
87 /* Return non-zero if FD is open in the given MODE, which is either
88 O_TEXT or O_BINARY. */
90 is_mode (int fd, int mode)
92 int value = setmode (fd, O_BINARY);
100 const char *file = "test-dup2.tmp";
102 int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600);
104 /* Assume std descriptors were provided by invoker. */
105 ASSERT (STDERR_FILENO < fd);
106 ASSERT (is_open (fd));
107 /* Ignore any other fd's leaked into this process. */
110 ASSERT (!is_open (fd + 1));
111 ASSERT (!is_open (fd + 2));
113 /* Assigning to self must be a no-op. */
114 ASSERT (dup2 (fd, fd) == fd);
115 ASSERT (is_open (fd));
117 /* The source must be valid. */
119 ASSERT (dup2 (-1, fd) == -1);
120 ASSERT (errno == EBADF);
122 ASSERT (dup2 (AT_FDCWD, fd) == -1);
123 ASSERT (errno == EBADF);
124 ASSERT (is_open (fd));
126 /* If the source is not open, then the destination is unaffected. */
128 ASSERT (dup2 (fd + 1, fd + 1) == -1);
129 ASSERT (errno == EBADF);
130 ASSERT (!is_open (fd + 1));
132 ASSERT (dup2 (fd + 1, fd) == -1);
133 ASSERT (errno == EBADF);
134 ASSERT (is_open (fd));
136 /* The destination must be valid. */
138 ASSERT (dup2 (fd, -2) == -1);
139 ASSERT (errno == EBADF);
141 ASSERT (dup2 (fd, 10000000) == -1);
142 ASSERT (errno == EBADF);
144 /* Using dup2 can skip fds. */
145 ASSERT (dup2 (fd, fd + 2) == fd + 2);
146 ASSERT (is_open (fd));
147 ASSERT (!is_open (fd + 1));
148 ASSERT (is_open (fd + 2));
150 /* Verify that dup2 closes the previous occupant of a fd. */
151 ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
152 ASSERT (dup2 (fd + 1, fd) == fd);
153 ASSERT (close (fd + 1) == 0);
154 ASSERT (write (fd, "1", 1) == 1);
155 ASSERT (dup2 (fd + 2, fd) == fd);
156 ASSERT (lseek (fd, 0, SEEK_END) == 0);
157 ASSERT (write (fd + 2, "2", 1) == 1);
158 ASSERT (lseek (fd, 0, SEEK_SET) == 0);
159 ASSERT (read (fd, buffer, 1) == 1);
160 ASSERT (*buffer == '2');
163 /* Any new fd created by dup2 must not be cloexec. */
164 ASSERT (close (fd + 2) == 0);
165 ASSERT (dup_cloexec (fd) == fd + 1);
166 ASSERT (!is_inheritable (fd + 1));
167 ASSERT (dup2 (fd + 1, fd + 1) == fd + 1);
168 ASSERT (!is_inheritable (fd + 1));
169 ASSERT (dup2 (fd + 1, fd + 2) == fd + 2);
170 ASSERT (is_inheritable (fd + 2));
173 /* On systems that distinguish between text and binary mode, dup2
174 reuses the mode of the source. */
175 setmode (fd, O_BINARY);
176 ASSERT (is_mode (fd, O_BINARY));
177 ASSERT (dup2 (fd, fd + 1) == fd + 1);
178 ASSERT (is_mode (fd + 1, O_BINARY));
179 setmode (fd, O_TEXT);
180 ASSERT (is_mode (fd, O_TEXT));
181 ASSERT (dup2 (fd, fd + 1) == fd + 1);
182 ASSERT (is_mode (fd + 1, O_TEXT));
185 ASSERT (close (fd + 2) == 0);
186 ASSERT (close (fd + 1) == 0);
187 ASSERT (close (fd) == 0);
188 ASSERT (unlink (file) == 0);