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));
31 #include "binary-io.h"
34 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
35 /* Get declarations of the Win32 API functions. */
36 # define WIN32_LEAN_AND_MEAN
40 #define ASSERT(expr) \
45 fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
52 /* Return non-zero if FD is open. */
56 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
57 /* On Win32, the initial state of unassigned standard file
58 descriptors is that they are open but point to an
59 INVALID_HANDLE_VALUE, and there is no fcntl. */
60 return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
63 # error Please port fcntl to your platform
65 return 0 <= fcntl (fd, F_GETFL);
69 /* Return non-zero if FD is open and inheritable across exec/spawn. */
71 is_inheritable (int fd)
73 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
74 /* On Win32, the initial state of unassigned standard file
75 descriptors is that they are open but point to an
76 INVALID_HANDLE_VALUE, and there is no fcntl. */
77 HANDLE h = (HANDLE) _get_osfhandle (fd);
79 if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
81 return (flags & HANDLE_FLAG_INHERIT) != 0;
84 # error Please port fcntl to your platform
86 int i = fcntl (fd, F_GETFD);
87 return 0 <= i && (i & FD_CLOEXEC) == 0;
92 # define setmode(f,m) zero ()
93 static int zero (void) { return 0; }
96 /* Return non-zero if FD is open in the given MODE, which is either
97 O_TEXT or O_BINARY. */
99 is_mode (int fd, int mode)
101 int value = setmode (fd, O_BINARY);
103 return mode == value;
109 const char *file = "test-dup2.tmp";
111 int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600);
113 /* Assume std descriptors were provided by invoker. */
114 ASSERT (STDERR_FILENO < fd);
115 ASSERT (is_open (fd));
116 /* Ignore any other fd's leaked into this process. */
119 ASSERT (!is_open (fd + 1));
120 ASSERT (!is_open (fd + 2));
122 /* Assigning to self must be a no-op. */
123 ASSERT (dup2 (fd, fd) == fd);
124 ASSERT (is_open (fd));
126 /* The source must be valid. */
128 ASSERT (dup2 (-1, fd) == -1);
129 ASSERT (errno == EBADF);
131 ASSERT (dup2 (AT_FDCWD, fd) == -1);
132 ASSERT (errno == EBADF);
133 ASSERT (is_open (fd));
135 /* If the source is not open, then the destination is unaffected. */
137 ASSERT (dup2 (fd + 1, fd + 1) == -1);
138 ASSERT (errno == EBADF);
139 ASSERT (!is_open (fd + 1));
141 ASSERT (dup2 (fd + 1, fd) == -1);
142 ASSERT (errno == EBADF);
143 ASSERT (is_open (fd));
145 /* The destination must be valid. */
147 ASSERT (dup2 (fd, -2) == -1);
148 ASSERT (errno == EBADF);
150 ASSERT (dup2 (fd, 10000000) == -1);
151 ASSERT (errno == EBADF);
153 /* Using dup2 can skip fds. */
154 ASSERT (dup2 (fd, fd + 2) == fd + 2);
155 ASSERT (is_open (fd));
156 ASSERT (!is_open (fd + 1));
157 ASSERT (is_open (fd + 2));
159 /* Verify that dup2 closes the previous occupant of a fd. */
160 ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
161 ASSERT (dup2 (fd + 1, fd) == fd);
162 ASSERT (close (fd + 1) == 0);
163 ASSERT (write (fd, "1", 1) == 1);
164 ASSERT (dup2 (fd + 2, fd) == fd);
165 ASSERT (lseek (fd, 0, SEEK_END) == 0);
166 ASSERT (write (fd + 2, "2", 1) == 1);
167 ASSERT (lseek (fd, 0, SEEK_SET) == 0);
168 ASSERT (read (fd, buffer, 1) == 1);
169 ASSERT (*buffer == '2');
171 /* Any new fd created by dup2 must not be cloexec. */
172 ASSERT (close (fd + 2) == 0);
173 ASSERT (dup_cloexec (fd) == fd + 1);
174 ASSERT (!is_inheritable (fd + 1));
175 ASSERT (dup2 (fd + 1, fd + 1) == fd + 1);
176 ASSERT (!is_inheritable (fd + 1));
177 ASSERT (dup2 (fd + 1, fd + 2) == fd + 2);
178 ASSERT (is_inheritable (fd + 2));
180 /* On systems that distinguish between text and binary mode, dup2
181 reuses the mode of the source. */
182 setmode (fd, O_BINARY);
183 ASSERT (is_mode (fd, O_BINARY));
184 ASSERT (dup2 (fd, fd + 1) == fd + 1);
185 ASSERT (is_mode (fd + 1, O_BINARY));
186 setmode (fd, O_TEXT);
187 ASSERT (is_mode (fd, O_TEXT));
188 ASSERT (dup2 (fd, fd + 1) == fd + 1);
189 ASSERT (is_mode (fd + 1, O_TEXT));
192 ASSERT (close (fd + 2) == 0);
193 ASSERT (close (fd + 1) == 0);
194 ASSERT (close (fd) == 0);
195 ASSERT (unlink (file) == 0);