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