1 /* Test of fcntl(2).
2 Copyright (C) 2009-2020 Free Software Foundation, Inc.
3
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.
8
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.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17 /* Written by Eric Blake <ebb9@byu.net>, 2009. */
18
19 #include <config.h>
20
21 /* Specification. */
22 #include <fcntl.h>
23
24 #include "signature.h"
25 SIGNATURE_CHECK (fcntl, int, (int, int, ...));
26
27 /* Helpers. */
28 #include <errno.h>
29 #include <stdarg.h>
30 #include <stdbool.h>
31 #include <unistd.h>
32
33 #if defined _WIN32 && ! defined __CYGWIN__
34 /* Get declarations of the native Windows API functions. */
35 # define WIN32_LEAN_AND_MEAN
36 # include <windows.h>
37 /* Get _get_osfhandle. */
38 # if GNULIB_MSVC_NOTHROW
39 # include "msvc-nothrow.h"
40 # else
41 # include <io.h>
42 # endif
43 #endif
44
45 #include "binary-io.h"
46 #include "macros.h"
47
48 #if !O_BINARY
49 # define setmode(f,m) zero ()
zero(void)50 static int zero (void) { return 0; }
51 #endif
52
53 /* Return true if FD is open. */
54 static bool
is_open(int fd)55 is_open (int fd)
56 {
57 #if defined _WIN32 && ! defined __CYGWIN__
58 /* On native Windows, 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;
62 #else
63 # ifndef F_GETFL
64 # error Please port fcntl to your platform
65 # endif
66 return 0 <= fcntl (fd, F_GETFL);
67 #endif
68 }
69
70 /* Return true if FD is open and inheritable across exec/spawn. */
71 static bool
is_inheritable(int fd)72 is_inheritable (int fd)
73 {
74 #if defined _WIN32 && ! defined __CYGWIN__
75 /* On native Windows, the initial state of unassigned standard file
76 descriptors is that they are open but point to an
77 INVALID_HANDLE_VALUE, and there is no fcntl. */
78 HANDLE h = (HANDLE) _get_osfhandle (fd);
79 DWORD flags;
80 if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
81 return false;
82 return (flags & HANDLE_FLAG_INHERIT) != 0;
83 #else
84 # ifndef F_GETFD
85 # error Please port fcntl to your platform
86 # endif
87 int i = fcntl (fd, F_GETFD);
88 return 0 <= i && (i & FD_CLOEXEC) == 0;
89 #endif
90 }
91
92 /* Return non-zero if FD is open in the given MODE, which is either
93 O_TEXT or O_BINARY. */
94 static bool
is_mode(int fd,int mode)95 is_mode (int fd, int mode)
96 {
97 int value = setmode (fd, O_BINARY);
98 setmode (fd, value);
99 return mode == value;
100 }
101
102 /* Since native fcntl can have more supported operations than our
103 replacement is aware of, and since various operations assign
104 different types to the vararg argument, a wrapper around fcntl must
105 be able to pass a vararg of unknown type on through to the original
106 fcntl. Make sure that this works properly: func1 behaves like the
107 original fcntl interpreting the vararg as an int or a pointer to a
108 struct, and func2 behaves like rpl_fcntl that doesn't know what
109 type to forward. */
110 struct dummy_struct
111 {
112 long filler;
113 int value;
114 };
115 static int
func1(int a,...)116 func1 (int a, ...)
117 {
118 va_list arg;
119 int i;
120 va_start (arg, a);
121 if (a < 4)
122 i = va_arg (arg, int);
123 else
124 {
125 struct dummy_struct *s = va_arg (arg, struct dummy_struct *);
126 i = s->value;
127 }
128 va_end (arg);
129 return i;
130 }
131 static int
func2(int a,...)132 func2 (int a, ...)
133 {
134 va_list arg;
135 void *p;
136 va_start (arg, a);
137 p = va_arg (arg, void *);
138 va_end (arg);
139 return func1 (a, p);
140 }
141
142 /* Ensure that all supported fcntl actions are distinct, and
143 usable in preprocessor expressions. */
144 static void
check_flags(void)145 check_flags (void)
146 {
147 switch (0)
148 {
149 case F_DUPFD:
150 #if F_DUPFD
151 #endif
152
153 case F_DUPFD_CLOEXEC:
154 #if F_DUPFD_CLOEXEC
155 #endif
156
157 case F_GETFD:
158 #if F_GETFD
159 #endif
160
161 #ifdef F_SETFD
162 case F_SETFD:
163 # if F_SETFD
164 # endif
165 #endif
166
167 #ifdef F_GETFL
168 case F_GETFL:
169 # if F_GETFL
170 # endif
171 #endif
172
173 #ifdef F_SETFL
174 case F_SETFL:
175 # if F_SETFL
176 # endif
177 #endif
178
179 #ifdef F_GETOWN
180 case F_GETOWN:
181 # if F_GETOWN
182 # endif
183 #endif
184
185 #ifdef F_SETOWN
186 case F_SETOWN:
187 # if F_SETOWN
188 # endif
189 #endif
190
191 #ifdef F_GETLK
192 case F_GETLK:
193 # if F_GETLK
194 # endif
195 #endif
196
197 #ifdef F_SETLK
198 case F_SETLK:
199 # if F_SETLK
200 # endif
201 #endif
202
203 #ifdef F_SETLKW
204 case F_SETLKW:
205 # if F_SETLKW
206 # endif
207 #endif
208
209 ;
210 }
211 }
212
213 int
main(void)214 main (void)
215 {
216 const char *file = "test-fcntl.tmp";
217 int fd;
218 int bad_fd = getdtablesize ();
219
220 /* Sanity check that rpl_fcntl is likely to work. */
221 ASSERT (func2 (1, 2) == 2);
222 ASSERT (func2 (2, -2) == -2);
223 ASSERT (func2 (3, 0x80000000) == 0x80000000);
224 {
225 struct dummy_struct s = { 0L, 4 };
226 ASSERT (func2 (4, &s) == 4);
227 }
228 check_flags ();
229
230 /* Assume std descriptors were provided by invoker, and ignore fds
231 that might have been inherited. */
232 fd = creat (file, 0600);
233 ASSERT (STDERR_FILENO < fd);
234 close (fd + 1);
235 close (fd + 2);
236
237 /* For F_DUPFD*, the source must be valid. */
238 errno = 0;
239 ASSERT (fcntl (-1, F_DUPFD, 0) == -1);
240 ASSERT (errno == EBADF);
241 errno = 0;
242 ASSERT (fcntl (fd + 1, F_DUPFD, 0) == -1);
243 ASSERT (errno == EBADF);
244 errno = 0;
245 ASSERT (fcntl (bad_fd, F_DUPFD, 0) == -1);
246 ASSERT (errno == EBADF);
247 errno = 0;
248 ASSERT (fcntl (-1, F_DUPFD_CLOEXEC, 0) == -1);
249 ASSERT (errno == EBADF);
250 errno = 0;
251 ASSERT (fcntl (fd + 1, F_DUPFD_CLOEXEC, 0) == -1);
252 ASSERT (errno == EBADF);
253 errno = 0;
254 ASSERT (fcntl (bad_fd, F_DUPFD_CLOEXEC, 0) == -1);
255 ASSERT (errno == EBADF);
256
257 /* For F_DUPFD*, the destination must be valid. */
258 errno = 0;
259 ASSERT (fcntl (fd, F_DUPFD, -1) == -1);
260 ASSERT (errno == EINVAL);
261 errno = 0;
262 ASSERT (fcntl (fd, F_DUPFD, bad_fd) == -1);
263 ASSERT (errno == EINVAL);
264 errno = 0;
265 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, -1) == -1);
266 ASSERT (errno == EINVAL);
267 errno = 0;
268 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, bad_fd) == -1);
269 ASSERT (errno == EINVAL
270 || errno == EMFILE /* WSL */);
271
272 /* For F_DUPFD*, check for correct inheritance, as well as
273 preservation of text vs. binary. */
274 setmode (fd, O_BINARY);
275 ASSERT (is_open (fd));
276 ASSERT (!is_open (fd + 1));
277 ASSERT (!is_open (fd + 2));
278 ASSERT (is_inheritable (fd));
279 ASSERT (is_mode (fd, O_BINARY));
280
281 ASSERT (fcntl (fd, F_DUPFD, fd) == fd + 1);
282 ASSERT (is_open (fd));
283 ASSERT (is_open (fd + 1));
284 ASSERT (!is_open (fd + 2));
285 ASSERT (is_inheritable (fd + 1));
286 ASSERT (is_mode (fd, O_BINARY));
287 ASSERT (is_mode (fd + 1, O_BINARY));
288 ASSERT (close (fd + 1) == 0);
289
290 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, fd + 2) == fd + 2);
291 ASSERT (is_open (fd));
292 ASSERT (!is_open (fd + 1));
293 ASSERT (is_open (fd + 2));
294 ASSERT (is_inheritable (fd));
295 ASSERT (!is_inheritable (fd + 2));
296 ASSERT (is_mode (fd, O_BINARY));
297 ASSERT (is_mode (fd + 2, O_BINARY));
298 ASSERT (close (fd) == 0);
299
300 setmode (fd + 2, O_TEXT);
301 ASSERT (fcntl (fd + 2, F_DUPFD, fd + 1) == fd + 1);
302 ASSERT (!is_open (fd));
303 ASSERT (is_open (fd + 1));
304 ASSERT (is_open (fd + 2));
305 ASSERT (is_inheritable (fd + 1));
306 ASSERT (!is_inheritable (fd + 2));
307 ASSERT (is_mode (fd + 1, O_TEXT));
308 ASSERT (is_mode (fd + 2, O_TEXT));
309 ASSERT (close (fd + 1) == 0);
310
311 ASSERT (fcntl (fd + 2, F_DUPFD_CLOEXEC, 0) == fd);
312 ASSERT (is_open (fd));
313 ASSERT (!is_open (fd + 1));
314 ASSERT (is_open (fd + 2));
315 ASSERT (!is_inheritable (fd));
316 ASSERT (!is_inheritable (fd + 2));
317 ASSERT (is_mode (fd, O_TEXT));
318 ASSERT (is_mode (fd + 2, O_TEXT));
319 ASSERT (close (fd + 2) == 0);
320
321 /* Test F_GETFD on invalid file descriptors. */
322 errno = 0;
323 ASSERT (fcntl (-1, F_GETFD) == -1);
324 ASSERT (errno == EBADF);
325 errno = 0;
326 ASSERT (fcntl (fd + 1, F_GETFD) == -1);
327 ASSERT (errno == EBADF);
328 errno = 0;
329 ASSERT (fcntl (bad_fd, F_GETFD) == -1);
330 ASSERT (errno == EBADF);
331
332 /* Test F_GETFD, the FD_CLOEXEC bit. */
333 {
334 int result = fcntl (fd, F_GETFD);
335 ASSERT (0 <= result);
336 ASSERT ((result & FD_CLOEXEC) == FD_CLOEXEC);
337 ASSERT (dup (fd) == fd + 1);
338 result = fcntl (fd + 1, F_GETFD);
339 ASSERT (0 <= result);
340 ASSERT ((result & FD_CLOEXEC) == 0);
341 ASSERT (close (fd + 1) == 0);
342 }
343
344 #ifdef F_SETFD
345 /* Test F_SETFD on invalid file descriptors. */
346 errno = 0;
347 ASSERT (fcntl (-1, F_SETFD, 0) == -1);
348 ASSERT (errno == EBADF);
349 errno = 0;
350 ASSERT (fcntl (fd + 1, F_SETFD, 0) == -1);
351 ASSERT (errno == EBADF);
352 errno = 0;
353 ASSERT (fcntl (bad_fd, F_SETFD, 0) == -1);
354 ASSERT (errno == EBADF);
355 #endif
356
357 #ifdef F_GETFL
358 /* Test F_GETFL on invalid file descriptors. */
359 errno = 0;
360 ASSERT (fcntl (-1, F_GETFL) == -1);
361 ASSERT (errno == EBADF);
362 errno = 0;
363 ASSERT (fcntl (fd + 1, F_GETFL) == -1);
364 ASSERT (errno == EBADF);
365 errno = 0;
366 ASSERT (fcntl (bad_fd, F_GETFL) == -1);
367 ASSERT (errno == EBADF);
368 #endif
369
370 #ifdef F_SETFL
371 /* Test F_SETFL on invalid file descriptors. */
372 errno = 0;
373 ASSERT (fcntl (-1, F_SETFL, 0) == -1);
374 ASSERT (errno == EBADF);
375 errno = 0;
376 ASSERT (fcntl (fd + 1, F_SETFL, 0) == -1);
377 ASSERT (errno == EBADF);
378 errno = 0;
379 ASSERT (fcntl (bad_fd, F_SETFL, 0) == -1);
380 ASSERT (errno == EBADF);
381 #endif
382
383 #ifdef F_GETOWN
384 /* Test F_GETOWN on invalid file descriptors. */
385 errno = 0;
386 ASSERT (fcntl (-1, F_GETOWN) == -1);
387 ASSERT (errno == EBADF);
388 errno = 0;
389 ASSERT (fcntl (fd + 1, F_GETOWN) == -1);
390 ASSERT (errno == EBADF);
391 errno = 0;
392 ASSERT (fcntl (bad_fd, F_GETOWN) == -1);
393 ASSERT (errno == EBADF);
394 #endif
395
396 #ifdef F_SETOWN
397 /* Test F_SETFL on invalid file descriptors. */
398 errno = 0;
399 ASSERT (fcntl (-1, F_SETOWN, 0) == -1);
400 ASSERT (errno == EBADF);
401 errno = 0;
402 ASSERT (fcntl (fd + 1, F_SETOWN, 0) == -1);
403 ASSERT (errno == EBADF);
404 errno = 0;
405 ASSERT (fcntl (bad_fd, F_SETOWN, 0) == -1);
406 ASSERT (errno == EBADF);
407 #endif
408
409 /* Cleanup. */
410 ASSERT (close (fd) == 0);
411 ASSERT (unlink (file) == 0);
412
413 return 0;
414 }
415