1 /* Test of fcntl(2).
2 Copyright (C) 2009-2022 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 set_binary_mode(f,m) zero ()
50 static int zero (void) { return 0; }
51 #endif
52
53 /* Return true if FD is open. */
54 static bool
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
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
95 is_mode (int fd, int mode)
96 {
97 int value = set_binary_mode (fd, O_BINARY);
98 set_binary_mode (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
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
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
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 default:
210 ;
211 }
212 }
213
214 int
215 main (int argc, char *argv[])
216 {
217 if (argc > 1)
218 /* child process */
219 return (is_open (10) ? 42 : 0);
220
221 const char *file = "test-fcntl.tmp";
222 int fd;
223 int bad_fd = getdtablesize ();
224
225 /* Sanity check that rpl_fcntl is likely to work. */
226 ASSERT (func2 (1, 2) == 2);
227 ASSERT (func2 (2, -2) == -2);
228 ASSERT (func2 (3, 0x80000000) == 0x80000000);
229 {
230 struct dummy_struct s = { 0L, 4 };
231 ASSERT (func2 (4, &s) == 4);
232 }
233 check_flags ();
234
235 /* Assume std descriptors were provided by invoker, and ignore fds
236 that might have been inherited. */
237 fd = creat (file, 0600);
238 ASSERT (STDERR_FILENO < fd);
239 close (fd + 1);
240 close (fd + 2);
241
242 /* For F_DUPFD*, the source must be valid. */
243 errno = 0;
244 ASSERT (fcntl (-1, F_DUPFD, 0) == -1);
245 ASSERT (errno == EBADF);
246 errno = 0;
247 ASSERT (fcntl (fd + 1, F_DUPFD, 0) == -1);
248 ASSERT (errno == EBADF);
249 errno = 0;
250 ASSERT (fcntl (bad_fd, F_DUPFD, 0) == -1);
251 ASSERT (errno == EBADF);
252 errno = 0;
253 ASSERT (fcntl (-1, F_DUPFD_CLOEXEC, 0) == -1);
254 ASSERT (errno == EBADF);
255 errno = 0;
256 ASSERT (fcntl (fd + 1, F_DUPFD_CLOEXEC, 0) == -1);
257 ASSERT (errno == EBADF);
258 errno = 0;
259 ASSERT (fcntl (bad_fd, F_DUPFD_CLOEXEC, 0) == -1);
260 ASSERT (errno == EBADF);
261
262 /* For F_DUPFD*, the destination must be valid. */
263 errno = 0;
264 ASSERT (fcntl (fd, F_DUPFD, -1) == -1);
265 ASSERT (errno == EINVAL);
266 errno = 0;
267 ASSERT (fcntl (fd, F_DUPFD, bad_fd) == -1);
268 ASSERT (errno == EINVAL);
269 errno = 0;
270 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, -1) == -1);
271 ASSERT (errno == EINVAL);
272 errno = 0;
273 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, bad_fd) == -1);
274 ASSERT (errno == EINVAL
275 || errno == EMFILE /* WSL */);
276
277 /* For F_DUPFD*, check for correct inheritance, as well as
278 preservation of text vs. binary. */
279 set_binary_mode (fd, O_BINARY);
280 ASSERT (is_open (fd));
281 ASSERT (!is_open (fd + 1));
282 ASSERT (!is_open (fd + 2));
283 ASSERT (is_inheritable (fd));
284 ASSERT (is_mode (fd, O_BINARY));
285
286 ASSERT (fcntl (fd, F_DUPFD, fd) == fd + 1);
287 ASSERT (is_open (fd));
288 ASSERT (is_open (fd + 1));
289 ASSERT (!is_open (fd + 2));
290 ASSERT (is_inheritable (fd + 1));
291 ASSERT (is_mode (fd, O_BINARY));
292 ASSERT (is_mode (fd + 1, O_BINARY));
293 ASSERT (close (fd + 1) == 0);
294
295 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, fd + 2) == fd + 2);
296 ASSERT (is_open (fd));
297 ASSERT (!is_open (fd + 1));
298 ASSERT (is_open (fd + 2));
299 ASSERT (is_inheritable (fd));
300 ASSERT (!is_inheritable (fd + 2));
301 ASSERT (is_mode (fd, O_BINARY));
302 ASSERT (is_mode (fd + 2, O_BINARY));
303 ASSERT (close (fd) == 0);
304
305 set_binary_mode (fd + 2, O_TEXT);
306 ASSERT (fcntl (fd + 2, F_DUPFD, fd + 1) == fd + 1);
307 ASSERT (!is_open (fd));
308 ASSERT (is_open (fd + 1));
309 ASSERT (is_open (fd + 2));
310 ASSERT (is_inheritable (fd + 1));
311 ASSERT (!is_inheritable (fd + 2));
312 ASSERT (is_mode (fd + 1, O_TEXT));
313 ASSERT (is_mode (fd + 2, O_TEXT));
314 ASSERT (close (fd + 1) == 0);
315
316 ASSERT (fcntl (fd + 2, F_DUPFD_CLOEXEC, 0) == fd);
317 ASSERT (is_open (fd));
318 ASSERT (!is_open (fd + 1));
319 ASSERT (is_open (fd + 2));
320 ASSERT (!is_inheritable (fd));
321 ASSERT (!is_inheritable (fd + 2));
322 ASSERT (is_mode (fd, O_TEXT));
323 ASSERT (is_mode (fd + 2, O_TEXT));
324 ASSERT (close (fd + 2) == 0);
325
326 /* Test F_GETFD on invalid file descriptors. */
327 errno = 0;
328 ASSERT (fcntl (-1, F_GETFD) == -1);
329 ASSERT (errno == EBADF);
330 errno = 0;
331 ASSERT (fcntl (fd + 1, F_GETFD) == -1);
332 ASSERT (errno == EBADF);
333 errno = 0;
334 ASSERT (fcntl (bad_fd, F_GETFD) == -1);
335 ASSERT (errno == EBADF);
336
337 /* Test F_GETFD, the FD_CLOEXEC bit. */
338 {
339 int result = fcntl (fd, F_GETFD);
340 ASSERT (0 <= result);
341 ASSERT ((result & FD_CLOEXEC) == FD_CLOEXEC);
342 ASSERT (dup (fd) == fd + 1);
343 result = fcntl (fd + 1, F_GETFD);
344 ASSERT (0 <= result);
345 ASSERT ((result & FD_CLOEXEC) == 0);
346 ASSERT (close (fd + 1) == 0);
347 }
348
349 #ifdef F_SETFD
350 /* Test F_SETFD on invalid file descriptors. */
351 errno = 0;
352 ASSERT (fcntl (-1, F_SETFD, 0) == -1);
353 ASSERT (errno == EBADF);
354 errno = 0;
355 ASSERT (fcntl (fd + 1, F_SETFD, 0) == -1);
356 ASSERT (errno == EBADF);
357 errno = 0;
358 ASSERT (fcntl (bad_fd, F_SETFD, 0) == -1);
359 ASSERT (errno == EBADF);
360 #endif
361
362 #ifdef F_GETFL
363 /* Test F_GETFL on invalid file descriptors. */
364 errno = 0;
365 ASSERT (fcntl (-1, F_GETFL) == -1);
366 ASSERT (errno == EBADF);
367 errno = 0;
368 ASSERT (fcntl (fd + 1, F_GETFL) == -1);
369 ASSERT (errno == EBADF);
370 errno = 0;
371 ASSERT (fcntl (bad_fd, F_GETFL) == -1);
372 ASSERT (errno == EBADF);
373 #endif
374
375 #ifdef F_SETFL
376 /* Test F_SETFL on invalid file descriptors. */
377 errno = 0;
378 ASSERT (fcntl (-1, F_SETFL, 0) == -1);
379 ASSERT (errno == EBADF);
380 errno = 0;
381 ASSERT (fcntl (fd + 1, F_SETFL, 0) == -1);
382 ASSERT (errno == EBADF);
383 errno = 0;
384 ASSERT (fcntl (bad_fd, F_SETFL, 0) == -1);
385 ASSERT (errno == EBADF);
386 #endif
387
388 #ifdef F_GETOWN
389 /* Test F_GETOWN on invalid file descriptors. */
390 errno = 0;
391 ASSERT (fcntl (-1, F_GETOWN) == -1);
392 ASSERT (errno == EBADF);
393 errno = 0;
394 ASSERT (fcntl (fd + 1, F_GETOWN) == -1);
395 ASSERT (errno == EBADF);
396 errno = 0;
397 ASSERT (fcntl (bad_fd, F_GETOWN) == -1);
398 ASSERT (errno == EBADF);
399 #endif
400
401 #ifdef F_SETOWN
402 /* Test F_SETFL on invalid file descriptors. */
403 errno = 0;
404 ASSERT (fcntl (-1, F_SETOWN, 0) == -1);
405 ASSERT (errno == EBADF);
406 errno = 0;
407 ASSERT (fcntl (fd + 1, F_SETOWN, 0) == -1);
408 ASSERT (errno == EBADF);
409 errno = 0;
410 ASSERT (fcntl (bad_fd, F_SETOWN, 0) == -1);
411 ASSERT (errno == EBADF);
412 #endif
413
414 /* Cleanup. */
415 ASSERT (close (fd) == 0);
416 ASSERT (unlink (file) == 0);
417
418 /* Close file descriptors that may have been inherited from the parent
419 process and that would cause failures below.
420 Such file descriptors have been seen:
421 - with GNU make, when invoked as 'make -j N' with j > 1,
422 - in some versions of the KDE desktop environment,
423 - on NetBSD,
424 - in MacPorts with the "trace mode" enabled.
425 */
426 (void) close (10);
427
428 /* Test whether F_DUPFD_CLOEXEC is effective. */
429 ASSERT (fcntl (1, F_DUPFD_CLOEXEC, 10) >= 0);
430 #if defined _WIN32 && !defined __CYGWIN__
431 return _execl ("./test-fcntl", "./test-fcntl", "child", NULL);
432 #else
433 return execl ("./test-fcntl", "./test-fcntl", "child", NULL);
434 #endif
435 }