Commit | Line | Data |
---|---|---|
9fd92637 DG |
1 | /* |
2 | * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License, version 2 only, as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
15 | * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | */ | |
17 | ||
6c1c0768 | 18 | #define _LGPL_SOURCE |
9fd92637 DG |
19 | #include <assert.h> |
20 | #include <fcntl.h> | |
21 | #include <unistd.h> | |
9c2bd8db JG |
22 | #include <sys/types.h> |
23 | #include <sys/stat.h> | |
9fd92637 DG |
24 | |
25 | #include <common/common.h> | |
26 | ||
27 | #include "pipe.h" | |
28 | ||
29 | /* | |
30 | * Lock read side of a pipe. | |
31 | */ | |
32 | static void lock_read_side(struct lttng_pipe *pipe) | |
33 | { | |
34 | pthread_mutex_lock(&pipe->read_mutex); | |
35 | } | |
36 | ||
37 | /* | |
38 | * Unlock read side of a pipe. | |
39 | */ | |
40 | static void unlock_read_side(struct lttng_pipe *pipe) | |
41 | { | |
42 | pthread_mutex_unlock(&pipe->read_mutex); | |
43 | } | |
44 | ||
45 | /* | |
46 | * Lock write side of a pipe. | |
47 | */ | |
48 | static void lock_write_side(struct lttng_pipe *pipe) | |
49 | { | |
50 | pthread_mutex_lock(&pipe->write_mutex); | |
51 | } | |
52 | ||
53 | /* | |
54 | * Unlock write side of a pipe. | |
55 | */ | |
56 | static void unlock_write_side(struct lttng_pipe *pipe) | |
57 | { | |
58 | pthread_mutex_unlock(&pipe->write_mutex); | |
59 | } | |
60 | ||
61 | /* | |
62 | * Internal function. Close read side of pipe WITHOUT locking the mutex. | |
63 | * | |
64 | * Return 0 on success else a negative errno from close(2). | |
65 | */ | |
66 | static int _pipe_read_close(struct lttng_pipe *pipe) | |
67 | { | |
68 | int ret, ret_val = 0; | |
69 | ||
70 | assert(pipe); | |
71 | ||
72 | if (!lttng_pipe_is_read_open(pipe)) { | |
73 | goto end; | |
74 | } | |
75 | ||
76 | do { | |
77 | ret = close(pipe->fd[0]); | |
78 | } while (ret < 0 && errno == EINTR); | |
79 | if (ret < 0) { | |
80 | PERROR("close lttng read pipe"); | |
81 | ret_val = -errno; | |
82 | } | |
83 | pipe->r_state = LTTNG_PIPE_STATE_CLOSED; | |
84 | ||
85 | end: | |
86 | return ret_val; | |
87 | } | |
88 | ||
89 | /* | |
90 | * Internal function. Close write side of pipe WITHOUT locking the mutex. | |
91 | * | |
92 | * Return 0 on success else a negative errno from close(2). | |
93 | */ | |
94 | static int _pipe_write_close(struct lttng_pipe *pipe) | |
95 | { | |
96 | int ret, ret_val = 0; | |
97 | ||
98 | assert(pipe); | |
99 | ||
100 | if (!lttng_pipe_is_write_open(pipe)) { | |
101 | goto end; | |
102 | } | |
103 | ||
104 | do { | |
105 | ret = close(pipe->fd[1]); | |
106 | } while (ret < 0 && errno == EINTR); | |
107 | if (ret < 0) { | |
108 | PERROR("close lttng write pipe"); | |
109 | ret_val = -errno; | |
110 | } | |
111 | pipe->w_state = LTTNG_PIPE_STATE_CLOSED; | |
112 | ||
113 | end: | |
114 | return ret_val; | |
115 | } | |
116 | ||
9c2bd8db JG |
117 | static struct lttng_pipe *_pipe_create(void) |
118 | { | |
119 | int ret; | |
120 | struct lttng_pipe *p; | |
121 | ||
122 | p = zmalloc(sizeof(*p)); | |
123 | if (!p) { | |
124 | PERROR("zmalloc pipe create"); | |
125 | goto end; | |
126 | } | |
127 | p->fd[0] = p->fd[1] = -1; | |
128 | ||
129 | ret = pthread_mutex_init(&p->read_mutex, NULL); | |
130 | if (ret) { | |
131 | PERROR("pthread_mutex_init read lock pipe create"); | |
132 | goto error_destroy; | |
133 | } | |
134 | ret = pthread_mutex_init(&p->write_mutex, NULL); | |
135 | if (ret) { | |
136 | PERROR("pthread_mutex_init write lock pipe create"); | |
137 | goto error_destroy_rmutex; | |
138 | } | |
139 | end: | |
140 | return p; | |
141 | error_destroy_rmutex: | |
142 | (void) pthread_mutex_destroy(&p->read_mutex); | |
143 | error_destroy: | |
144 | free(p); | |
145 | return NULL; | |
146 | } | |
147 | ||
148 | static int _pipe_set_flags(struct lttng_pipe *pipe, int flags) | |
149 | { | |
150 | int i, ret = 0; | |
151 | ||
152 | if (!flags) { | |
153 | goto end; | |
154 | } | |
155 | ||
156 | for (i = 0; i < 2; i++) { | |
699f8738 JD |
157 | if (flags & O_NONBLOCK) { |
158 | ret = fcntl(pipe->fd[i], F_SETFL, O_NONBLOCK); | |
159 | if (ret < 0) { | |
160 | PERROR("fcntl lttng pipe %d", flags); | |
161 | goto end; | |
162 | } | |
163 | } | |
164 | if (flags & FD_CLOEXEC) { | |
165 | ret = fcntl(pipe->fd[i], F_SETFD, FD_CLOEXEC); | |
166 | if (ret < 0) { | |
167 | PERROR("fcntl lttng pipe %d", flags); | |
168 | goto end; | |
169 | } | |
170 | } | |
171 | /* | |
172 | * We only check for O_NONBLOCK or FD_CLOEXEC, if another flag is | |
173 | * needed, we can add it, but for now just make sure we don't make | |
174 | * mistakes with the parameters we pass. | |
175 | */ | |
176 | if (!(flags & O_NONBLOCK) && !(flags & FD_CLOEXEC)) { | |
177 | fprintf(stderr, "Unsupported flag\n"); | |
178 | ret = -1; | |
9c2bd8db JG |
179 | goto end; |
180 | } | |
181 | } | |
182 | end: | |
183 | return ret; | |
184 | } | |
9fd92637 DG |
185 | |
186 | /* | |
187 | * Open a new lttng pipe and set flags using fcntl(). | |
188 | * | |
189 | * Return a newly allocated lttng pipe on success or else NULL. | |
190 | */ | |
a247c6e0 | 191 | LTTNG_HIDDEN |
9fd92637 DG |
192 | struct lttng_pipe *lttng_pipe_open(int flags) |
193 | { | |
194 | int ret; | |
195 | struct lttng_pipe *p; | |
196 | ||
9c2bd8db | 197 | p = _pipe_create(); |
9fd92637 | 198 | if (!p) { |
9fd92637 DG |
199 | goto error; |
200 | } | |
201 | ||
202 | ret = pipe(p->fd); | |
203 | if (ret < 0) { | |
204 | PERROR("lttng pipe"); | |
205 | goto error; | |
206 | } | |
9c2bd8db JG |
207 | p->r_state = LTTNG_PIPE_STATE_OPENED; |
208 | p->w_state = LTTNG_PIPE_STATE_OPENED; | |
9fd92637 | 209 | |
9c2bd8db JG |
210 | ret = _pipe_set_flags(p, flags); |
211 | if (ret) { | |
212 | goto error; | |
9fd92637 DG |
213 | } |
214 | ||
9fd92637 DG |
215 | p->flags = flags; |
216 | ||
217 | return p; | |
9fd92637 DG |
218 | error: |
219 | lttng_pipe_destroy(p); | |
220 | return NULL; | |
221 | } | |
222 | ||
9c2bd8db JG |
223 | /* |
224 | * Open a new lttng pipe at path and set flags using fcntl(). | |
225 | * | |
226 | * Return a newly allocated lttng pipe on success or else NULL. | |
227 | */ | |
228 | LTTNG_HIDDEN | |
229 | struct lttng_pipe *lttng_pipe_named_open(const char *path, mode_t mode, | |
230 | int flags) | |
231 | { | |
232 | int ret, fd_r, fd_w; | |
233 | struct lttng_pipe *pipe; | |
234 | ||
235 | pipe = _pipe_create(); | |
236 | if (!pipe) { | |
237 | goto error; | |
238 | } | |
239 | ||
240 | ret = mkfifo(path, mode); | |
241 | if (ret) { | |
242 | PERROR("mkfifo"); | |
243 | goto error; | |
244 | } | |
245 | ||
246 | fd_r = open(path, O_RDONLY | O_NONBLOCK); | |
247 | if (fd_r < 0) { | |
248 | PERROR("open fifo"); | |
9c2bd8db JG |
249 | goto error; |
250 | } | |
251 | pipe->fd[0] = fd_r; | |
252 | pipe->r_state = LTTNG_PIPE_STATE_OPENED; | |
253 | ||
254 | fd_w = open(path, O_WRONLY | O_NONBLOCK); | |
255 | if (fd_w < 0) { | |
256 | PERROR("open fifo"); | |
9c2bd8db JG |
257 | goto error; |
258 | } | |
259 | pipe->fd[1] = fd_w; | |
260 | pipe->w_state = LTTNG_PIPE_STATE_OPENED; | |
261 | ||
262 | ret = _pipe_set_flags(pipe, flags); | |
263 | if (ret) { | |
264 | goto error; | |
265 | } | |
266 | pipe->flags = flags; | |
267 | ||
268 | return pipe; | |
269 | error: | |
270 | lttng_pipe_destroy(pipe); | |
271 | return NULL; | |
272 | } | |
273 | ||
9fd92637 DG |
274 | /* |
275 | * Close read side of a lttng pipe. | |
276 | * | |
277 | * Return 0 on success else a negative value. | |
278 | */ | |
a247c6e0 | 279 | LTTNG_HIDDEN |
9fd92637 DG |
280 | int lttng_pipe_read_close(struct lttng_pipe *pipe) |
281 | { | |
282 | int ret; | |
283 | ||
284 | assert(pipe); | |
285 | ||
286 | /* Handle read side first. */ | |
287 | lock_read_side(pipe); | |
288 | ret = _pipe_read_close(pipe); | |
289 | unlock_read_side(pipe); | |
290 | ||
291 | return ret; | |
292 | } | |
293 | ||
294 | /* | |
295 | * Close write side of a lttng pipe. | |
296 | * | |
297 | * Return 0 on success else a negative value. | |
298 | */ | |
a247c6e0 | 299 | LTTNG_HIDDEN |
9fd92637 DG |
300 | int lttng_pipe_write_close(struct lttng_pipe *pipe) |
301 | { | |
302 | int ret; | |
303 | ||
304 | assert(pipe); | |
305 | ||
306 | lock_write_side(pipe); | |
307 | ret = _pipe_write_close(pipe); | |
308 | unlock_write_side(pipe); | |
309 | ||
310 | return ret; | |
311 | } | |
312 | ||
313 | /* | |
314 | * Close both read and write side of a lttng pipe. | |
315 | * | |
316 | * Return 0 on success else a negative value. | |
317 | */ | |
a247c6e0 | 318 | LTTNG_HIDDEN |
9fd92637 DG |
319 | int lttng_pipe_close(struct lttng_pipe *pipe) |
320 | { | |
321 | int ret, ret_val = 0; | |
322 | ||
323 | assert(pipe); | |
324 | ||
325 | ret = lttng_pipe_read_close(pipe); | |
326 | if (ret < 0) { | |
327 | ret_val = ret; | |
328 | } | |
329 | ||
330 | ret = lttng_pipe_write_close(pipe); | |
331 | if (ret < 0) { | |
332 | ret_val = ret; | |
333 | } | |
334 | ||
335 | return ret_val; | |
336 | } | |
337 | ||
338 | /* | |
339 | * Close and destroy a lttng pipe object. Finally, pipe is freed. | |
340 | */ | |
a247c6e0 | 341 | LTTNG_HIDDEN |
9fd92637 DG |
342 | void lttng_pipe_destroy(struct lttng_pipe *pipe) |
343 | { | |
344 | int ret; | |
345 | ||
346 | if (!pipe) { | |
347 | return; | |
348 | } | |
349 | ||
350 | /* | |
351 | * Destroy should *never* be called with a locked mutex. These must always | |
352 | * succeed so we unlock them after the close pipe below. | |
353 | */ | |
354 | ret = pthread_mutex_trylock(&pipe->read_mutex); | |
355 | assert(!ret); | |
356 | ret = pthread_mutex_trylock(&pipe->write_mutex); | |
357 | assert(!ret); | |
358 | ||
359 | /* Close pipes WITHOUT trying to lock the pipes. */ | |
360 | (void) _pipe_read_close(pipe); | |
361 | (void) _pipe_write_close(pipe); | |
362 | ||
363 | unlock_read_side(pipe); | |
364 | unlock_write_side(pipe); | |
365 | ||
366 | (void) pthread_mutex_destroy(&pipe->read_mutex); | |
367 | (void) pthread_mutex_destroy(&pipe->write_mutex); | |
368 | ||
369 | free(pipe); | |
370 | } | |
371 | ||
372 | /* | |
373 | * Read on a lttng pipe and put the data in buf of at least size count. | |
374 | * | |
6cd525e8 MD |
375 | * Return "count" on success. Return < count on error. errno can be used |
376 | * to check the actual error. | |
9fd92637 | 377 | */ |
a247c6e0 | 378 | LTTNG_HIDDEN |
9fd92637 DG |
379 | ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count) |
380 | { | |
6cd525e8 | 381 | ssize_t ret; |
9fd92637 DG |
382 | |
383 | assert(pipe); | |
384 | assert(buf); | |
385 | ||
386 | lock_read_side(pipe); | |
9fd92637 | 387 | if (!lttng_pipe_is_read_open(pipe)) { |
6cd525e8 MD |
388 | ret = -1; |
389 | errno = EBADF; | |
9fd92637 DG |
390 | goto error; |
391 | } | |
6cd525e8 | 392 | ret = lttng_read(pipe->fd[0], buf, count); |
9fd92637 DG |
393 | error: |
394 | unlock_read_side(pipe); | |
395 | return ret; | |
396 | } | |
397 | ||
398 | /* | |
399 | * Write on a lttng pipe using the data in buf and size of count. | |
400 | * | |
6cd525e8 MD |
401 | * Return "count" on success. Return < count on error. errno can be used |
402 | * to check the actual error. | |
9fd92637 | 403 | */ |
a247c6e0 | 404 | LTTNG_HIDDEN |
9fd92637 DG |
405 | ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf, |
406 | size_t count) | |
407 | { | |
6cd525e8 | 408 | ssize_t ret; |
9fd92637 DG |
409 | |
410 | assert(pipe); | |
411 | assert(buf); | |
412 | ||
413 | lock_write_side(pipe); | |
9fd92637 | 414 | if (!lttng_pipe_is_write_open(pipe)) { |
6cd525e8 MD |
415 | ret = -1; |
416 | errno = EBADF; | |
9fd92637 DG |
417 | goto error; |
418 | } | |
6cd525e8 | 419 | ret = lttng_write(pipe->fd[1], buf, count); |
9fd92637 DG |
420 | error: |
421 | unlock_write_side(pipe); | |
422 | return ret; | |
423 | } | |
55dfb029 JG |
424 | |
425 | /* | |
426 | * Return and release the read end of the pipe. | |
427 | * | |
428 | * This call transfers the ownership of the read fd of the underlying pipe | |
429 | * to the caller if it is still open. | |
430 | * | |
431 | * Returns the fd of the read end of the pipe, or -1 if it was already closed or | |
432 | * released. | |
433 | */ | |
434 | LTTNG_HIDDEN | |
435 | int lttng_pipe_release_readfd(struct lttng_pipe *pipe) | |
436 | { | |
437 | int ret; | |
438 | ||
439 | if (!pipe) { | |
440 | ret = -1; | |
441 | goto end; | |
442 | } | |
443 | ||
444 | lock_read_side(pipe); | |
445 | if (!lttng_pipe_is_read_open(pipe)) { | |
446 | ret = -1; | |
447 | goto end_unlock; | |
448 | } | |
449 | ret = pipe->fd[0]; | |
450 | pipe->fd[0] = -1; | |
451 | pipe->r_state = LTTNG_PIPE_STATE_CLOSED; | |
452 | end_unlock: | |
453 | unlock_read_side(pipe); | |
454 | end: | |
455 | return ret; | |
456 | } | |
457 | ||
458 | /* | |
459 | * Return and release the write end of the pipe. | |
460 | * | |
461 | * This call transfers the ownership of the write fd of the underlying pipe | |
462 | * to the caller if it is still open. | |
463 | * | |
464 | * Returns the fd of the write end of the pipe, or -1 if it was alwritey closed | |
465 | * or released. | |
466 | */ | |
467 | LTTNG_HIDDEN | |
468 | int lttng_pipe_release_writefd(struct lttng_pipe *pipe) | |
469 | { | |
470 | int ret; | |
471 | ||
472 | if (!pipe) { | |
473 | ret = -1; | |
474 | goto end; | |
475 | } | |
476 | ||
477 | lock_write_side(pipe); | |
478 | if (!lttng_pipe_is_write_open(pipe)) { | |
479 | ret = -1; | |
480 | goto end_unlock; | |
481 | } | |
482 | ret = pipe->fd[1]; | |
483 | pipe->fd[1] = -1; | |
484 | pipe->w_state = LTTNG_PIPE_STATE_CLOSED; | |
485 | end_unlock: | |
486 | unlock_write_side(pipe); | |
487 | end: | |
488 | return ret; | |
489 | } |