1 /* Test of fcntl(2).
2 Copyright (C) 2009-2023 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 <unistd.h>
31
32 #if defined _WIN32 && ! defined __CYGWIN__
33 /* Get declarations of the native Windows API functions. */
34 # define WIN32_LEAN_AND_MEAN
35 # include <windows.h>
36 /* Get _get_osfhandle. */
37 # if GNULIB_MSVC_NOTHROW
38 # include "msvc-nothrow.h"
39 # else
40 # include <io.h>
41 # endif
42 #endif
43
44 #include "binary-io.h"
45 #include "macros.h"
46
47 /* Tell GCC not to warn about the specific edge cases tested here. */
48 #if __GNUC__ >= 13
49 # pragma GCC diagnostic ignored "-Wanalyzer-fd-leak"
50 # pragma GCC diagnostic ignored "-Wanalyzer-va-arg-type-mismatch"
51 #endif
52
53 #if !O_BINARY
54 # define set_binary_mode my_set_binary_mode
55 static int
56 set_binary_mode (_GL_UNUSED int fd, _GL_UNUSED int mode)
57 {
58 return 0;
59 }
60 #endif
61
62 /* Return true if FD is open. */
63 static bool
64 is_open (int fd)
65 {
66 #if defined _WIN32 && ! defined __CYGWIN__
67 /* On native Windows, the initial state of unassigned standard file
68 descriptors is that they are open but point to an
69 INVALID_HANDLE_VALUE, and there is no fcntl. */
70 return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;
71 #else
72 # ifndef F_GETFL
73 # error Please port fcntl to your platform
74 # endif
75 return 0 <= fcntl (fd, F_GETFL);
76 #endif
77 }
78
79 /* Return true if FD is open and inheritable across exec/spawn. */
80 static bool
81 is_inheritable (int fd)
82 {
83 #if defined _WIN32 && ! defined __CYGWIN__
84 /* On native Windows, the initial state of unassigned standard file
85 descriptors is that they are open but point to an
86 INVALID_HANDLE_VALUE, and there is no fcntl. */
87 HANDLE h = (HANDLE) _get_osfhandle (fd);
88 DWORD flags;
89 if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)
90 return false;
91 return (flags & HANDLE_FLAG_INHERIT) != 0;
92 #else
93 # ifndef F_GETFD
94 # error Please port fcntl to your platform
95 # endif
96 int i = fcntl (fd, F_GETFD);
97 return 0 <= i && (i & FD_CLOEXEC) == 0;
98 #endif
99 }
100
101 /* Return non-zero if FD is open in the given MODE, which is either
102 O_TEXT or O_BINARY. */
103 static bool
104 is_mode (int fd, int mode)
105 {
106 int value = set_binary_mode (fd, O_BINARY);
107 set_binary_mode (fd, value);
108 return mode == value;
109 }
110
111 /* Since native fcntl can have more supported operations than our
112 replacement is aware of, and since various operations assign
113 different types to the vararg argument, a wrapper around fcntl must
114 be able to pass a vararg of unknown type on through to the original
115 fcntl. Make sure that this works properly: func1 behaves like the
116 original fcntl interpreting the vararg as an int or a pointer to a
117 struct, and func2 behaves like rpl_fcntl that doesn't know what
118 type to forward. */
119 struct dummy_struct
120 {
121 long filler;
122 int value;
123 };
124 static int
125 func1 (int a, ...)
126 {
127 va_list arg;
128 int i;
129 va_start (arg, a);
130 if (a < 4)
131 i = va_arg (arg, int);
132 else
133 {
134 struct dummy_struct *s = va_arg (arg, struct dummy_struct *);
135 i = s->value;
136 }
137 va_end (arg);
138 return i;
139 }
140 static int
141 func2 (int a, ...)
142 {
143 va_list arg;
144 void *p;
145 va_start (arg, a);
146 p = va_arg (arg, void *);
147 va_end (arg);
148 return func1 (a, p);
149 }
150
151 /* Ensure that all supported fcntl actions are distinct, and
152 usable in preprocessor expressions. */
153 static void
154 check_flags (void)
155 {
156 switch (0)
157 {
158 case F_DUPFD:
159 #if F_DUPFD
160 #endif
161
162 case F_DUPFD_CLOEXEC:
163 #if F_DUPFD_CLOEXEC
164 #endif
165
166 case F_GETFD:
167 #if F_GETFD
168 #endif
169
170 #ifdef F_SETFD
171 case F_SETFD:
172 # if F_SETFD
173 # endif
174 #endif
175
176 #ifdef F_GETFL
177 case F_GETFL:
178 # if F_GETFL
179 # endif
180 #endif
181
182 #ifdef F_SETFL
183 case F_SETFL:
184 # if F_SETFL
185 # endif
186 #endif
187
188 #ifdef F_GETOWN
189 case F_GETOWN:
190 # if F_GETOWN
191 # endif
192 #endif
193
194 #ifdef F_SETOWN
195 case F_SETOWN:
196 # if F_SETOWN
197 # endif
198 #endif
199
200 #ifdef F_GETLK
201 case F_GETLK:
202 # if F_GETLK
203 # endif
204 #endif
205
206 #ifdef F_SETLK
207 case F_SETLK:
208 # if F_SETLK
209 # endif
210 #endif
211
212 #ifdef F_SETLKW
213 case F_SETLKW:
214 # if F_SETLKW
215 # endif
216 #endif
217
218 default:
219 ;
220 }
221 }
222
223 int
224 main (int argc, _GL_UNUSED char *argv[])
225 {
226 if (argc > 1)
227 /* child process */
228 return (is_open (10) ? 42 : 0);
229
230 const char *file = "test-fcntl.tmp";
231 int fd;
232 int bad_fd = getdtablesize ();
233
234 /* Sanity check that rpl_fcntl is likely to work. */
235 ASSERT (func2 (1, 2) == 2);
236 ASSERT (func2 (2, -2) == -2);
237 ASSERT (func2 (3, 0x80000000) == 0x80000000);
238 {
239 struct dummy_struct s = { 0L, 4 };
240 ASSERT (func2 (4, &s) == 4);
241 }
242 check_flags ();
243
244 /* Assume std descriptors were provided by invoker, and ignore fds
245 that might have been inherited. */
246 fd = creat (file, 0600);
247 ASSERT (STDERR_FILENO < fd);
248 close (fd + 1);
249 close (fd + 2);
250
251 /* For F_DUPFD*, the source must be valid. */
252 errno = 0;
253 ASSERT (fcntl (-1, F_DUPFD, 0) == -1);
254 ASSERT (errno == EBADF);
255 errno = 0;
256 ASSERT (fcntl (fd + 1, F_DUPFD, 0) == -1);
257 ASSERT (errno == EBADF);
258 errno = 0;
259 ASSERT (fcntl (bad_fd, F_DUPFD, 0) == -1);
260 ASSERT (errno == EBADF);
261 errno = 0;
262 ASSERT (fcntl (-1, F_DUPFD_CLOEXEC, 0) == -1);
263 ASSERT (errno == EBADF);
264 errno = 0;
265 ASSERT (fcntl (fd + 1, F_DUPFD_CLOEXEC, 0) == -1);
266 ASSERT (errno == EBADF);
267 errno = 0;
268 ASSERT (fcntl (bad_fd, F_DUPFD_CLOEXEC, 0) == -1);
269 ASSERT (errno == EBADF);
270
271 /* For F_DUPFD*, the destination must be valid. */
272 errno = 0;
273 ASSERT (fcntl (fd, F_DUPFD, -1) == -1);
274 ASSERT (errno == EINVAL);
275 errno = 0;
276 ASSERT (fcntl (fd, F_DUPFD, bad_fd) == -1);
277 ASSERT (errno == EINVAL);
278 errno = 0;
279 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, -1) == -1);
280 ASSERT (errno == EINVAL);
281 errno = 0;
282 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, bad_fd) == -1);
283 ASSERT (errno == EINVAL
284 || errno == EMFILE /* WSL */);
285
286 /* For F_DUPFD*, check for correct inheritance, as well as
287 preservation of text vs. binary. */
288 set_binary_mode (fd, O_BINARY);
289 ASSERT (is_open (fd));
290 ASSERT (!is_open (fd + 1));
291 ASSERT (!is_open (fd + 2));
292 ASSERT (is_inheritable (fd));
293 ASSERT (is_mode (fd, O_BINARY));
294
295 ASSERT (fcntl (fd, F_DUPFD, fd) == fd + 1);
296 ASSERT (is_open (fd));
297 ASSERT (is_open (fd + 1));
298 ASSERT (!is_open (fd + 2));
299 ASSERT (is_inheritable (fd + 1));
300 ASSERT (is_mode (fd, O_BINARY));
301 ASSERT (is_mode (fd + 1, O_BINARY));
302 ASSERT (close (fd + 1) == 0);
303
304 ASSERT (fcntl (fd, F_DUPFD_CLOEXEC, fd + 2) == fd + 2);
305 ASSERT (is_open (fd));
306 ASSERT (!is_open (fd + 1));
307 ASSERT (is_open (fd + 2));
308 ASSERT (is_inheritable (fd));
309 ASSERT (!is_inheritable (fd + 2));
310 ASSERT (is_mode (fd, O_BINARY));
311 ASSERT (is_mode (fd + 2, O_BINARY));
312 ASSERT (close (fd) == 0);
313
314 set_binary_mode (fd + 2, O_TEXT);
315 ASSERT (fcntl (fd + 2, F_DUPFD, fd + 1) == fd + 1);
316 ASSERT (!is_open (fd));
317 ASSERT (is_open (fd + 1));
318 ASSERT (is_open (fd + 2));
319 ASSERT (is_inheritable (fd + 1));
320 ASSERT (!is_inheritable (fd + 2));
321 ASSERT (is_mode (fd + 1, O_TEXT));
322 ASSERT (is_mode (fd + 2, O_TEXT));
323 ASSERT (close (fd + 1) == 0);
324
325 ASSERT (fcntl (fd + 2, F_DUPFD_CLOEXEC, 0) == fd);
326 ASSERT (is_open (fd));
327 ASSERT (!is_open (fd + 1));
328 ASSERT (is_open (fd + 2));
329 ASSERT (!is_inheritable (fd));
330 ASSERT (!is_inheritable (fd + 2));
331 ASSERT (is_mode (fd, O_TEXT));
332 ASSERT (is_mode (fd + 2, O_TEXT));
333 ASSERT (close (fd + 2) == 0);
334
335 /* Test F_GETFD on invalid file descriptors. */
336 errno = 0;
337 ASSERT (fcntl (-1, F_GETFD) == -1);
338 ASSERT (errno == EBADF);
339 errno = 0;
340 ASSERT (fcntl (fd + 1, F_GETFD) == -1);
341 ASSERT (errno == EBADF);
342 errno = 0;
343 ASSERT (fcntl (bad_fd, F_GETFD) == -1);
344 ASSERT (errno == EBADF);
345
346 /* Test F_GETFD, the FD_CLOEXEC bit. */
347 {
348 int result = fcntl (fd, F_GETFD);
349 ASSERT (0 <= result);
350 ASSERT ((result & FD_CLOEXEC) == FD_CLOEXEC);
351 ASSERT (dup (fd) == fd + 1);
352 result = fcntl (fd + 1, F_GETFD);
353 ASSERT (0 <= result);
354 ASSERT ((result & FD_CLOEXEC) == 0);
355 ASSERT (close (fd + 1) == 0);
356 }
357
358 #ifdef F_SETFD
359 /* Test F_SETFD on invalid file descriptors. */
360 errno = 0;
361 ASSERT (fcntl (-1, F_SETFD, 0) == -1);
362 ASSERT (errno == EBADF);
363 errno = 0;
364 ASSERT (fcntl (fd + 1, F_SETFD, 0) == -1);
365 ASSERT (errno == EBADF);
366 errno = 0;
367 ASSERT (fcntl (bad_fd, F_SETFD, 0) == -1);
368 ASSERT (errno == EBADF);
369 #endif
370
371 #ifdef F_GETFL
372 /* Test F_GETFL on invalid file descriptors. */
373 errno = 0;
374 ASSERT (fcntl (-1, F_GETFL) == -1);
375 ASSERT (errno == EBADF);
376 errno = 0;
377 ASSERT (fcntl (fd + 1, F_GETFL) == -1);
378 ASSERT (errno == EBADF);
379 errno = 0;
380 ASSERT (fcntl (bad_fd, F_GETFL) == -1);
381 ASSERT (errno == EBADF);
382 #endif
383
384 #ifdef F_SETFL
385 /* Test F_SETFL on invalid file descriptors. */
386 errno = 0;
387 ASSERT (fcntl (-1, F_SETFL, 0) == -1);
388 ASSERT (errno == EBADF);
389 errno = 0;
390 ASSERT (fcntl (fd + 1, F_SETFL, 0) == -1);
391 ASSERT (errno == EBADF);
392 errno = 0;
393 ASSERT (fcntl (bad_fd, F_SETFL, 0) == -1);
394 ASSERT (errno == EBADF);
395 #endif
396
397 #ifdef F_GETOWN
398 /* Test F_GETOWN on invalid file descriptors. */
399 errno = 0;
400 ASSERT (fcntl (-1, F_GETOWN) == -1);
401 ASSERT (errno == EBADF);
402 errno = 0;
403 ASSERT (fcntl (fd + 1, F_GETOWN) == -1);
404 ASSERT (errno == EBADF);
405 errno = 0;
406 ASSERT (fcntl (bad_fd, F_GETOWN) == -1);
407 ASSERT (errno == EBADF);
408 #endif
409
410 #ifdef F_SETOWN
411 /* Test F_SETFL on invalid file descriptors. */
412 errno = 0;
413 ASSERT (fcntl (-1, F_SETOWN, 0) == -1);
414 ASSERT (errno == EBADF);
415 errno = 0;
416 ASSERT (fcntl (fd + 1, F_SETOWN, 0) == -1);
417 ASSERT (errno == EBADF);
418 errno = 0;
419 ASSERT (fcntl (bad_fd, F_SETOWN, 0) == -1);
420 ASSERT (errno == EBADF);
421 #endif
422
423 /* Cleanup. */
424 ASSERT (close (fd) == 0);
425 ASSERT (unlink (file) == 0);
426
427 /* Close file descriptors that may have been inherited from the parent
428 process and that would cause failures below.
429 Such file descriptors have been seen:
430 - with GNU make, when invoked as 'make -j N' with j > 1,
431 - in some versions of the KDE desktop environment,
432 - on NetBSD,
433 - in MacPorts with the "trace mode" enabled.
434 */
435 (void) close (10);
436
437 /* Test whether F_DUPFD_CLOEXEC is effective. */
438 ASSERT (fcntl (1, F_DUPFD_CLOEXEC, 10) >= 0);
439 #if defined _WIN32 && !defined __CYGWIN__
440 return _execl ("./test-fcntl", "./test-fcntl", "child", NULL);
441 #else
442 return execl ("./test-fcntl", "./test-fcntl", "child", NULL);
443 #endif
444 }