Commit | Line | Data |
---|---|---|
9fd92637 | 1 | /* |
ab5be9fa | 2 | * Copyright (C) 2013 David Goulet <dgoulet@efficios.com> |
9fd92637 | 3 | * |
ab5be9fa | 4 | * SPDX-License-Identifier: GPL-2.0-only |
9fd92637 | 5 | * |
9fd92637 DG |
6 | */ |
7 | ||
6c1c0768 | 8 | #define _LGPL_SOURCE |
9fd92637 DG |
9 | #include <assert.h> |
10 | #include <fcntl.h> | |
11 | #include <unistd.h> | |
9c2bd8db JG |
12 | #include <sys/types.h> |
13 | #include <sys/stat.h> | |
9fd92637 DG |
14 | |
15 | #include <common/common.h> | |
16 | ||
17 | #include "pipe.h" | |
18 | ||
19 | /* | |
20 | * Lock read side of a pipe. | |
21 | */ | |
22 | static void lock_read_side(struct lttng_pipe *pipe) | |
23 | { | |
24 | pthread_mutex_lock(&pipe->read_mutex); | |
25 | } | |
26 | ||
27 | /* | |
28 | * Unlock read side of a pipe. | |
29 | */ | |
30 | static void unlock_read_side(struct lttng_pipe *pipe) | |
31 | { | |
32 | pthread_mutex_unlock(&pipe->read_mutex); | |
33 | } | |
34 | ||
35 | /* | |
36 | * Lock write side of a pipe. | |
37 | */ | |
38 | static void lock_write_side(struct lttng_pipe *pipe) | |
39 | { | |
40 | pthread_mutex_lock(&pipe->write_mutex); | |
41 | } | |
42 | ||
43 | /* | |
44 | * Unlock write side of a pipe. | |
45 | */ | |
46 | static void unlock_write_side(struct lttng_pipe *pipe) | |
47 | { | |
48 | pthread_mutex_unlock(&pipe->write_mutex); | |
49 | } | |
50 | ||
51 | /* | |
52 | * Internal function. Close read side of pipe WITHOUT locking the mutex. | |
53 | * | |
54 | * Return 0 on success else a negative errno from close(2). | |
55 | */ | |
56 | static int _pipe_read_close(struct lttng_pipe *pipe) | |
57 | { | |
58 | int ret, ret_val = 0; | |
59 | ||
60 | assert(pipe); | |
61 | ||
62 | if (!lttng_pipe_is_read_open(pipe)) { | |
63 | goto end; | |
64 | } | |
65 | ||
66 | do { | |
67 | ret = close(pipe->fd[0]); | |
68 | } while (ret < 0 && errno == EINTR); | |
69 | if (ret < 0) { | |
70 | PERROR("close lttng read pipe"); | |
71 | ret_val = -errno; | |
72 | } | |
73 | pipe->r_state = LTTNG_PIPE_STATE_CLOSED; | |
74 | ||
75 | end: | |
76 | return ret_val; | |
77 | } | |
78 | ||
79 | /* | |
80 | * Internal function. Close write side of pipe WITHOUT locking the mutex. | |
81 | * | |
82 | * Return 0 on success else a negative errno from close(2). | |
83 | */ | |
84 | static int _pipe_write_close(struct lttng_pipe *pipe) | |
85 | { | |
86 | int ret, ret_val = 0; | |
87 | ||
88 | assert(pipe); | |
89 | ||
90 | if (!lttng_pipe_is_write_open(pipe)) { | |
91 | goto end; | |
92 | } | |
93 | ||
94 | do { | |
95 | ret = close(pipe->fd[1]); | |
96 | } while (ret < 0 && errno == EINTR); | |
97 | if (ret < 0) { | |
98 | PERROR("close lttng write pipe"); | |
99 | ret_val = -errno; | |
100 | } | |
101 | pipe->w_state = LTTNG_PIPE_STATE_CLOSED; | |
102 | ||
103 | end: | |
104 | return ret_val; | |
105 | } | |
106 | ||
9c2bd8db JG |
107 | static struct lttng_pipe *_pipe_create(void) |
108 | { | |
109 | int ret; | |
110 | struct lttng_pipe *p; | |
111 | ||
112 | p = zmalloc(sizeof(*p)); | |
113 | if (!p) { | |
114 | PERROR("zmalloc pipe create"); | |
115 | goto end; | |
116 | } | |
117 | p->fd[0] = p->fd[1] = -1; | |
118 | ||
119 | ret = pthread_mutex_init(&p->read_mutex, NULL); | |
120 | if (ret) { | |
121 | PERROR("pthread_mutex_init read lock pipe create"); | |
122 | goto error_destroy; | |
123 | } | |
124 | ret = pthread_mutex_init(&p->write_mutex, NULL); | |
125 | if (ret) { | |
126 | PERROR("pthread_mutex_init write lock pipe create"); | |
127 | goto error_destroy_rmutex; | |
128 | } | |
129 | end: | |
130 | return p; | |
131 | error_destroy_rmutex: | |
132 | (void) pthread_mutex_destroy(&p->read_mutex); | |
133 | error_destroy: | |
134 | free(p); | |
135 | return NULL; | |
136 | } | |
137 | ||
138 | static int _pipe_set_flags(struct lttng_pipe *pipe, int flags) | |
139 | { | |
140 | int i, ret = 0; | |
141 | ||
142 | if (!flags) { | |
143 | goto end; | |
144 | } | |
145 | ||
146 | for (i = 0; i < 2; i++) { | |
699f8738 JD |
147 | if (flags & O_NONBLOCK) { |
148 | ret = fcntl(pipe->fd[i], F_SETFL, O_NONBLOCK); | |
149 | if (ret < 0) { | |
150 | PERROR("fcntl lttng pipe %d", flags); | |
151 | goto end; | |
152 | } | |
153 | } | |
154 | if (flags & FD_CLOEXEC) { | |
155 | ret = fcntl(pipe->fd[i], F_SETFD, FD_CLOEXEC); | |
156 | if (ret < 0) { | |
157 | PERROR("fcntl lttng pipe %d", flags); | |
158 | goto end; | |
159 | } | |
160 | } | |
161 | /* | |
162 | * We only check for O_NONBLOCK or FD_CLOEXEC, if another flag is | |
163 | * needed, we can add it, but for now just make sure we don't make | |
164 | * mistakes with the parameters we pass. | |
165 | */ | |
166 | if (!(flags & O_NONBLOCK) && !(flags & FD_CLOEXEC)) { | |
167 | fprintf(stderr, "Unsupported flag\n"); | |
168 | ret = -1; | |
9c2bd8db JG |
169 | goto end; |
170 | } | |
171 | } | |
172 | end: | |
173 | return ret; | |
174 | } | |
9fd92637 DG |
175 | |
176 | /* | |
177 | * Open a new lttng pipe and set flags using fcntl(). | |
178 | * | |
179 | * Return a newly allocated lttng pipe on success or else NULL. | |
180 | */ | |
a247c6e0 | 181 | LTTNG_HIDDEN |
9fd92637 DG |
182 | struct lttng_pipe *lttng_pipe_open(int flags) |
183 | { | |
184 | int ret; | |
185 | struct lttng_pipe *p; | |
186 | ||
9c2bd8db | 187 | p = _pipe_create(); |
9fd92637 | 188 | if (!p) { |
9fd92637 DG |
189 | goto error; |
190 | } | |
191 | ||
192 | ret = pipe(p->fd); | |
193 | if (ret < 0) { | |
194 | PERROR("lttng pipe"); | |
195 | goto error; | |
196 | } | |
9c2bd8db JG |
197 | p->r_state = LTTNG_PIPE_STATE_OPENED; |
198 | p->w_state = LTTNG_PIPE_STATE_OPENED; | |
9fd92637 | 199 | |
9c2bd8db JG |
200 | ret = _pipe_set_flags(p, flags); |
201 | if (ret) { | |
202 | goto error; | |
9fd92637 DG |
203 | } |
204 | ||
9fd92637 DG |
205 | p->flags = flags; |
206 | ||
207 | return p; | |
9fd92637 DG |
208 | error: |
209 | lttng_pipe_destroy(p); | |
210 | return NULL; | |
211 | } | |
212 | ||
9c2bd8db JG |
213 | /* |
214 | * Open a new lttng pipe at path and set flags using fcntl(). | |
215 | * | |
216 | * Return a newly allocated lttng pipe on success or else NULL. | |
217 | */ | |
218 | LTTNG_HIDDEN | |
219 | struct lttng_pipe *lttng_pipe_named_open(const char *path, mode_t mode, | |
220 | int flags) | |
221 | { | |
222 | int ret, fd_r, fd_w; | |
223 | struct lttng_pipe *pipe; | |
224 | ||
225 | pipe = _pipe_create(); | |
226 | if (!pipe) { | |
227 | goto error; | |
228 | } | |
229 | ||
230 | ret = mkfifo(path, mode); | |
231 | if (ret) { | |
232 | PERROR("mkfifo"); | |
233 | goto error; | |
234 | } | |
235 | ||
236 | fd_r = open(path, O_RDONLY | O_NONBLOCK); | |
237 | if (fd_r < 0) { | |
238 | PERROR("open fifo"); | |
9c2bd8db JG |
239 | goto error; |
240 | } | |
241 | pipe->fd[0] = fd_r; | |
242 | pipe->r_state = LTTNG_PIPE_STATE_OPENED; | |
243 | ||
244 | fd_w = open(path, O_WRONLY | O_NONBLOCK); | |
245 | if (fd_w < 0) { | |
246 | PERROR("open fifo"); | |
9c2bd8db JG |
247 | goto error; |
248 | } | |
249 | pipe->fd[1] = fd_w; | |
250 | pipe->w_state = LTTNG_PIPE_STATE_OPENED; | |
251 | ||
252 | ret = _pipe_set_flags(pipe, flags); | |
253 | if (ret) { | |
254 | goto error; | |
255 | } | |
256 | pipe->flags = flags; | |
257 | ||
258 | return pipe; | |
259 | error: | |
260 | lttng_pipe_destroy(pipe); | |
261 | return NULL; | |
262 | } | |
263 | ||
9fd92637 DG |
264 | /* |
265 | * Close read side of a lttng pipe. | |
266 | * | |
267 | * Return 0 on success else a negative value. | |
268 | */ | |
a247c6e0 | 269 | LTTNG_HIDDEN |
9fd92637 DG |
270 | int lttng_pipe_read_close(struct lttng_pipe *pipe) |
271 | { | |
272 | int ret; | |
273 | ||
274 | assert(pipe); | |
275 | ||
276 | /* Handle read side first. */ | |
277 | lock_read_side(pipe); | |
278 | ret = _pipe_read_close(pipe); | |
279 | unlock_read_side(pipe); | |
280 | ||
281 | return ret; | |
282 | } | |
283 | ||
284 | /* | |
285 | * Close write side of a lttng pipe. | |
286 | * | |
287 | * Return 0 on success else a negative value. | |
288 | */ | |
a247c6e0 | 289 | LTTNG_HIDDEN |
9fd92637 DG |
290 | int lttng_pipe_write_close(struct lttng_pipe *pipe) |
291 | { | |
292 | int ret; | |
293 | ||
294 | assert(pipe); | |
295 | ||
296 | lock_write_side(pipe); | |
297 | ret = _pipe_write_close(pipe); | |
298 | unlock_write_side(pipe); | |
299 | ||
300 | return ret; | |
301 | } | |
302 | ||
303 | /* | |
304 | * Close both read and write side of a lttng pipe. | |
305 | * | |
306 | * Return 0 on success else a negative value. | |
307 | */ | |
a247c6e0 | 308 | LTTNG_HIDDEN |
9fd92637 DG |
309 | int lttng_pipe_close(struct lttng_pipe *pipe) |
310 | { | |
311 | int ret, ret_val = 0; | |
312 | ||
313 | assert(pipe); | |
314 | ||
315 | ret = lttng_pipe_read_close(pipe); | |
316 | if (ret < 0) { | |
317 | ret_val = ret; | |
318 | } | |
319 | ||
320 | ret = lttng_pipe_write_close(pipe); | |
321 | if (ret < 0) { | |
322 | ret_val = ret; | |
323 | } | |
324 | ||
325 | return ret_val; | |
326 | } | |
327 | ||
328 | /* | |
329 | * Close and destroy a lttng pipe object. Finally, pipe is freed. | |
330 | */ | |
a247c6e0 | 331 | LTTNG_HIDDEN |
9fd92637 DG |
332 | void lttng_pipe_destroy(struct lttng_pipe *pipe) |
333 | { | |
334 | int ret; | |
335 | ||
336 | if (!pipe) { | |
337 | return; | |
338 | } | |
339 | ||
340 | /* | |
341 | * Destroy should *never* be called with a locked mutex. These must always | |
342 | * succeed so we unlock them after the close pipe below. | |
343 | */ | |
344 | ret = pthread_mutex_trylock(&pipe->read_mutex); | |
345 | assert(!ret); | |
346 | ret = pthread_mutex_trylock(&pipe->write_mutex); | |
347 | assert(!ret); | |
348 | ||
349 | /* Close pipes WITHOUT trying to lock the pipes. */ | |
350 | (void) _pipe_read_close(pipe); | |
351 | (void) _pipe_write_close(pipe); | |
352 | ||
353 | unlock_read_side(pipe); | |
354 | unlock_write_side(pipe); | |
355 | ||
356 | (void) pthread_mutex_destroy(&pipe->read_mutex); | |
357 | (void) pthread_mutex_destroy(&pipe->write_mutex); | |
358 | ||
359 | free(pipe); | |
360 | } | |
361 | ||
362 | /* | |
363 | * Read on a lttng pipe and put the data in buf of at least size count. | |
364 | * | |
6cd525e8 MD |
365 | * Return "count" on success. Return < count on error. errno can be used |
366 | * to check the actual error. | |
9fd92637 | 367 | */ |
a247c6e0 | 368 | LTTNG_HIDDEN |
9fd92637 DG |
369 | ssize_t lttng_pipe_read(struct lttng_pipe *pipe, void *buf, size_t count) |
370 | { | |
6cd525e8 | 371 | ssize_t ret; |
9fd92637 DG |
372 | |
373 | assert(pipe); | |
374 | assert(buf); | |
375 | ||
376 | lock_read_side(pipe); | |
9fd92637 | 377 | if (!lttng_pipe_is_read_open(pipe)) { |
6cd525e8 MD |
378 | ret = -1; |
379 | errno = EBADF; | |
9fd92637 DG |
380 | goto error; |
381 | } | |
6cd525e8 | 382 | ret = lttng_read(pipe->fd[0], buf, count); |
9fd92637 DG |
383 | error: |
384 | unlock_read_side(pipe); | |
385 | return ret; | |
386 | } | |
387 | ||
388 | /* | |
389 | * Write on a lttng pipe using the data in buf and size of count. | |
390 | * | |
6cd525e8 MD |
391 | * Return "count" on success. Return < count on error. errno can be used |
392 | * to check the actual error. | |
9fd92637 | 393 | */ |
a247c6e0 | 394 | LTTNG_HIDDEN |
9fd92637 DG |
395 | ssize_t lttng_pipe_write(struct lttng_pipe *pipe, const void *buf, |
396 | size_t count) | |
397 | { | |
6cd525e8 | 398 | ssize_t ret; |
9fd92637 DG |
399 | |
400 | assert(pipe); | |
401 | assert(buf); | |
402 | ||
403 | lock_write_side(pipe); | |
9fd92637 | 404 | if (!lttng_pipe_is_write_open(pipe)) { |
6cd525e8 MD |
405 | ret = -1; |
406 | errno = EBADF; | |
9fd92637 DG |
407 | goto error; |
408 | } | |
6cd525e8 | 409 | ret = lttng_write(pipe->fd[1], buf, count); |
9fd92637 DG |
410 | error: |
411 | unlock_write_side(pipe); | |
412 | return ret; | |
413 | } | |
55dfb029 JG |
414 | |
415 | /* | |
416 | * Return and release the read end of the pipe. | |
417 | * | |
418 | * This call transfers the ownership of the read fd of the underlying pipe | |
419 | * to the caller if it is still open. | |
420 | * | |
421 | * Returns the fd of the read end of the pipe, or -1 if it was already closed or | |
422 | * released. | |
423 | */ | |
424 | LTTNG_HIDDEN | |
425 | int lttng_pipe_release_readfd(struct lttng_pipe *pipe) | |
426 | { | |
427 | int ret; | |
428 | ||
429 | if (!pipe) { | |
430 | ret = -1; | |
431 | goto end; | |
432 | } | |
433 | ||
434 | lock_read_side(pipe); | |
435 | if (!lttng_pipe_is_read_open(pipe)) { | |
436 | ret = -1; | |
437 | goto end_unlock; | |
438 | } | |
439 | ret = pipe->fd[0]; | |
440 | pipe->fd[0] = -1; | |
441 | pipe->r_state = LTTNG_PIPE_STATE_CLOSED; | |
442 | end_unlock: | |
443 | unlock_read_side(pipe); | |
444 | end: | |
445 | return ret; | |
446 | } | |
447 | ||
448 | /* | |
449 | * Return and release the write end of the pipe. | |
450 | * | |
451 | * This call transfers the ownership of the write fd of the underlying pipe | |
452 | * to the caller if it is still open. | |
453 | * | |
454 | * Returns the fd of the write end of the pipe, or -1 if it was alwritey closed | |
455 | * or released. | |
456 | */ | |
457 | LTTNG_HIDDEN | |
458 | int lttng_pipe_release_writefd(struct lttng_pipe *pipe) | |
459 | { | |
460 | int ret; | |
461 | ||
462 | if (!pipe) { | |
463 | ret = -1; | |
464 | goto end; | |
465 | } | |
466 | ||
467 | lock_write_side(pipe); | |
468 | if (!lttng_pipe_is_write_open(pipe)) { | |
469 | ret = -1; | |
470 | goto end_unlock; | |
471 | } | |
472 | ret = pipe->fd[1]; | |
473 | pipe->fd[1] = -1; | |
474 | pipe->w_state = LTTNG_PIPE_STATE_CLOSED; | |
475 | end_unlock: | |
476 | unlock_write_side(pipe); | |
477 | end: | |
478 | return ret; | |
479 | } |