Commit | Line | Data |
---|---|---|
5d1b0219 | 1 | /* |
ab5be9fa MJ |
2 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> |
3 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | * Copyright (C) 2013 Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
5d1b0219 | 5 | * |
ab5be9fa | 6 | * SPDX-License-Identifier: GPL-2.0-only |
5d1b0219 | 7 | * |
5d1b0219 JG |
8 | */ |
9 | ||
10 | #include <stddef.h> | |
11 | #include <stdlib.h> | |
12 | #include <urcu.h> | |
13 | #include <common/futex.h> | |
14 | #include <common/macros.h> | |
15 | ||
16 | #include "dispatch.h" | |
17 | #include "ust-app.h" | |
18 | #include "testpoint.h" | |
19 | #include "fd-limit.h" | |
20 | #include "health-sessiond.h" | |
21 | #include "lttng-sessiond.h" | |
22 | #include "thread.h" | |
23 | ||
24 | struct thread_notifiers { | |
25 | struct ust_cmd_queue *ust_cmd_queue; | |
26 | int apps_cmd_pipe_write_fd; | |
27 | int apps_cmd_notify_pipe_write_fd; | |
28 | int dispatch_thread_exit; | |
29 | }; | |
30 | ||
31 | /* | |
32 | * For each tracing session, update newly registered apps. The session list | |
33 | * lock MUST be acquired before calling this. | |
34 | */ | |
35 | static void update_ust_app(int app_sock) | |
36 | { | |
37 | struct ltt_session *sess, *stmp; | |
38 | const struct ltt_session_list *session_list = session_get_list(); | |
39 | ||
40 | /* Consumer is in an ERROR state. Stop any application update. */ | |
41 | if (uatomic_read(&ust_consumerd_state) == CONSUMER_ERROR) { | |
42 | /* Stop the update process since the consumer is dead. */ | |
43 | return; | |
44 | } | |
45 | ||
46 | /* For all tracing session(s) */ | |
47 | cds_list_for_each_entry_safe(sess, stmp, &session_list->head, list) { | |
48 | struct ust_app *app; | |
49 | ||
50 | if (!session_get(sess)) { | |
51 | continue; | |
52 | } | |
53 | session_lock(sess); | |
e5b7dd9f JR |
54 | if (!sess->active || !sess->ust_session || |
55 | !sess->ust_session->active) { | |
5d1b0219 JG |
56 | goto unlock_session; |
57 | } | |
58 | ||
59 | rcu_read_lock(); | |
60 | assert(app_sock >= 0); | |
61 | app = ust_app_find_by_sock(app_sock); | |
62 | if (app == NULL) { | |
63 | /* | |
64 | * Application can be unregistered before so | |
65 | * this is possible hence simply stopping the | |
66 | * update. | |
67 | */ | |
68 | DBG3("UST app update failed to find app sock %d", | |
69 | app_sock); | |
70 | goto unlock_rcu; | |
71 | } | |
72 | ust_app_global_update(sess->ust_session, app); | |
73 | unlock_rcu: | |
74 | rcu_read_unlock(); | |
75 | unlock_session: | |
76 | session_unlock(sess); | |
77 | session_put(sess); | |
78 | } | |
79 | } | |
80 | ||
81 | /* | |
82 | * Sanitize the wait queue of the dispatch registration thread meaning removing | |
83 | * invalid nodes from it. This is to avoid memory leaks for the case the UST | |
84 | * notify socket is never received. | |
85 | */ | |
86 | static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue) | |
87 | { | |
88 | int ret, nb_fd = 0, i; | |
89 | unsigned int fd_added = 0; | |
90 | struct lttng_poll_event events; | |
91 | struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node; | |
92 | ||
93 | assert(wait_queue); | |
94 | ||
95 | lttng_poll_init(&events); | |
96 | ||
97 | /* Just skip everything for an empty queue. */ | |
98 | if (!wait_queue->count) { | |
99 | goto end; | |
100 | } | |
101 | ||
102 | ret = lttng_poll_create(&events, wait_queue->count, LTTNG_CLOEXEC); | |
103 | if (ret < 0) { | |
104 | goto error_create; | |
105 | } | |
106 | ||
107 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, | |
108 | &wait_queue->head, head) { | |
109 | assert(wait_node->app); | |
110 | ret = lttng_poll_add(&events, wait_node->app->sock, | |
111 | LPOLLHUP | LPOLLERR); | |
112 | if (ret < 0) { | |
113 | goto error; | |
114 | } | |
115 | ||
116 | fd_added = 1; | |
117 | } | |
118 | ||
119 | if (!fd_added) { | |
120 | goto end; | |
121 | } | |
122 | ||
123 | /* | |
124 | * Poll but don't block so we can quickly identify the faulty events and | |
125 | * clean them afterwards from the wait queue. | |
126 | */ | |
127 | ret = lttng_poll_wait(&events, 0); | |
128 | if (ret < 0) { | |
129 | goto error; | |
130 | } | |
131 | nb_fd = ret; | |
132 | ||
133 | for (i = 0; i < nb_fd; i++) { | |
134 | /* Get faulty FD. */ | |
135 | uint32_t revents = LTTNG_POLL_GETEV(&events, i); | |
136 | int pollfd = LTTNG_POLL_GETFD(&events, i); | |
137 | ||
5d1b0219 JG |
138 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, |
139 | &wait_queue->head, head) { | |
140 | if (pollfd == wait_node->app->sock && | |
141 | (revents & (LPOLLHUP | LPOLLERR))) { | |
142 | cds_list_del(&wait_node->head); | |
143 | wait_queue->count--; | |
144 | ust_app_destroy(wait_node->app); | |
145 | free(wait_node); | |
146 | /* | |
147 | * Silence warning of use-after-free in | |
148 | * cds_list_for_each_entry_safe which uses | |
149 | * __typeof__(*wait_node). | |
150 | */ | |
151 | wait_node = NULL; | |
152 | break; | |
153 | } else { | |
154 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); | |
155 | goto error; | |
156 | } | |
157 | } | |
158 | } | |
159 | ||
160 | if (nb_fd > 0) { | |
161 | DBG("Wait queue sanitized, %d node were cleaned up", nb_fd); | |
162 | } | |
163 | ||
164 | end: | |
165 | lttng_poll_clean(&events); | |
166 | return; | |
167 | ||
168 | error: | |
169 | lttng_poll_clean(&events); | |
170 | error_create: | |
171 | ERR("Unable to sanitize wait queue"); | |
172 | return; | |
173 | } | |
174 | ||
175 | /* | |
176 | * Send a socket to a thread This is called from the dispatch UST registration | |
177 | * thread once all sockets are set for the application. | |
178 | * | |
179 | * The sock value can be invalid, we don't really care, the thread will handle | |
180 | * it and make the necessary cleanup if so. | |
181 | * | |
182 | * On success, return 0 else a negative value being the errno message of the | |
183 | * write(). | |
184 | */ | |
185 | static int send_socket_to_thread(int fd, int sock) | |
186 | { | |
187 | ssize_t ret; | |
188 | ||
189 | /* | |
190 | * It's possible that the FD is set as invalid with -1 concurrently just | |
191 | * before calling this function being a shutdown state of the thread. | |
192 | */ | |
193 | if (fd < 0) { | |
194 | ret = -EBADF; | |
195 | goto error; | |
196 | } | |
197 | ||
198 | ret = lttng_write(fd, &sock, sizeof(sock)); | |
199 | if (ret < sizeof(sock)) { | |
200 | PERROR("write apps pipe %d", fd); | |
201 | if (ret < 0) { | |
202 | ret = -errno; | |
203 | } | |
204 | goto error; | |
205 | } | |
206 | ||
207 | /* All good. Don't send back the write positive ret value. */ | |
208 | ret = 0; | |
209 | error: | |
210 | return (int) ret; | |
211 | } | |
212 | ||
213 | static void cleanup_ust_dispatch_thread(void *data) | |
214 | { | |
215 | free(data); | |
216 | } | |
217 | ||
218 | /* | |
219 | * Dispatch request from the registration threads to the application | |
220 | * communication thread. | |
221 | */ | |
222 | static void *thread_dispatch_ust_registration(void *data) | |
223 | { | |
224 | int ret, err = -1; | |
225 | struct cds_wfcq_node *node; | |
226 | struct ust_command *ust_cmd = NULL; | |
227 | struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node; | |
228 | struct ust_reg_wait_queue wait_queue = { | |
229 | .count = 0, | |
230 | }; | |
231 | struct thread_notifiers *notifiers = data; | |
232 | ||
233 | rcu_register_thread(); | |
234 | ||
235 | health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG_DISPATCH); | |
236 | ||
237 | if (testpoint(sessiond_thread_app_reg_dispatch)) { | |
238 | goto error_testpoint; | |
239 | } | |
240 | ||
241 | health_code_update(); | |
242 | ||
243 | CDS_INIT_LIST_HEAD(&wait_queue.head); | |
244 | ||
245 | DBG("[thread] Dispatch UST command started"); | |
246 | ||
247 | for (;;) { | |
248 | health_code_update(); | |
249 | ||
250 | /* Atomically prepare the queue futex */ | |
251 | futex_nto1_prepare(¬ifiers->ust_cmd_queue->futex); | |
252 | ||
253 | if (CMM_LOAD_SHARED(notifiers->dispatch_thread_exit)) { | |
254 | break; | |
255 | } | |
256 | ||
257 | do { | |
258 | struct ust_app *app = NULL; | |
259 | ust_cmd = NULL; | |
260 | ||
261 | /* | |
262 | * Make sure we don't have node(s) that have hung up before receiving | |
263 | * the notify socket. This is to clean the list in order to avoid | |
264 | * memory leaks from notify socket that are never seen. | |
265 | */ | |
266 | sanitize_wait_queue(&wait_queue); | |
267 | ||
268 | health_code_update(); | |
269 | /* Dequeue command for registration */ | |
270 | node = cds_wfcq_dequeue_blocking( | |
271 | ¬ifiers->ust_cmd_queue->head, | |
272 | ¬ifiers->ust_cmd_queue->tail); | |
273 | if (node == NULL) { | |
274 | DBG("Woken up but nothing in the UST command queue"); | |
275 | /* Continue thread execution */ | |
276 | break; | |
277 | } | |
278 | ||
279 | ust_cmd = caa_container_of(node, struct ust_command, node); | |
280 | ||
281 | DBG("Dispatching UST registration pid:%d ppid:%d uid:%d" | |
282 | " gid:%d sock:%d name:%s (version %d.%d)", | |
283 | ust_cmd->reg_msg.pid, ust_cmd->reg_msg.ppid, | |
284 | ust_cmd->reg_msg.uid, ust_cmd->reg_msg.gid, | |
285 | ust_cmd->sock, ust_cmd->reg_msg.name, | |
286 | ust_cmd->reg_msg.major, ust_cmd->reg_msg.minor); | |
287 | ||
288 | if (ust_cmd->reg_msg.type == USTCTL_SOCKET_CMD) { | |
289 | wait_node = zmalloc(sizeof(*wait_node)); | |
290 | if (!wait_node) { | |
291 | PERROR("zmalloc wait_node dispatch"); | |
292 | ret = close(ust_cmd->sock); | |
293 | if (ret < 0) { | |
294 | PERROR("close ust sock dispatch %d", ust_cmd->sock); | |
295 | } | |
296 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
297 | free(ust_cmd); | |
58f835e1 | 298 | ust_cmd = NULL; |
5d1b0219 JG |
299 | goto error; |
300 | } | |
301 | CDS_INIT_LIST_HEAD(&wait_node->head); | |
302 | ||
303 | /* Create application object if socket is CMD. */ | |
304 | wait_node->app = ust_app_create(&ust_cmd->reg_msg, | |
305 | ust_cmd->sock); | |
306 | if (!wait_node->app) { | |
307 | ret = close(ust_cmd->sock); | |
308 | if (ret < 0) { | |
309 | PERROR("close ust sock dispatch %d", ust_cmd->sock); | |
310 | } | |
311 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
312 | free(wait_node); | |
58f835e1 | 313 | wait_node = NULL; |
5d1b0219 | 314 | free(ust_cmd); |
58f835e1 | 315 | ust_cmd = NULL; |
5d1b0219 JG |
316 | continue; |
317 | } | |
318 | /* | |
319 | * Add application to the wait queue so we can set the notify | |
320 | * socket before putting this object in the global ht. | |
321 | */ | |
322 | cds_list_add(&wait_node->head, &wait_queue.head); | |
323 | wait_queue.count++; | |
324 | ||
325 | free(ust_cmd); | |
58f835e1 | 326 | ust_cmd = NULL; |
5d1b0219 JG |
327 | /* |
328 | * We have to continue here since we don't have the notify | |
329 | * socket and the application MUST be added to the hash table | |
330 | * only at that moment. | |
331 | */ | |
332 | continue; | |
333 | } else { | |
334 | /* | |
335 | * Look for the application in the local wait queue and set the | |
336 | * notify socket if found. | |
337 | */ | |
338 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, | |
339 | &wait_queue.head, head) { | |
340 | health_code_update(); | |
341 | if (wait_node->app->pid == ust_cmd->reg_msg.pid) { | |
342 | wait_node->app->notify_sock = ust_cmd->sock; | |
343 | cds_list_del(&wait_node->head); | |
344 | wait_queue.count--; | |
345 | app = wait_node->app; | |
346 | free(wait_node); | |
58f835e1 | 347 | wait_node = NULL; |
5d1b0219 JG |
348 | DBG3("UST app notify socket %d is set", ust_cmd->sock); |
349 | break; | |
350 | } | |
351 | } | |
352 | ||
353 | /* | |
354 | * With no application at this stage the received socket is | |
355 | * basically useless so close it before we free the cmd data | |
356 | * structure for good. | |
357 | */ | |
358 | if (!app) { | |
359 | ret = close(ust_cmd->sock); | |
360 | if (ret < 0) { | |
361 | PERROR("close ust sock dispatch %d", ust_cmd->sock); | |
362 | } | |
363 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
364 | } | |
365 | free(ust_cmd); | |
58f835e1 | 366 | ust_cmd = NULL; |
5d1b0219 JG |
367 | } |
368 | ||
369 | if (app) { | |
370 | /* | |
371 | * @session_lock_list | |
372 | * | |
373 | * Lock the global session list so from the register up to the | |
374 | * registration done message, no thread can see the application | |
375 | * and change its state. | |
376 | */ | |
377 | session_lock_list(); | |
378 | rcu_read_lock(); | |
379 | ||
380 | /* | |
381 | * Add application to the global hash table. This needs to be | |
382 | * done before the update to the UST registry can locate the | |
383 | * application. | |
384 | */ | |
385 | ust_app_add(app); | |
386 | ||
387 | /* Set app version. This call will print an error if needed. */ | |
388 | (void) ust_app_version(app); | |
389 | ||
390 | /* Send notify socket through the notify pipe. */ | |
391 | ret = send_socket_to_thread( | |
392 | notifiers->apps_cmd_notify_pipe_write_fd, | |
393 | app->notify_sock); | |
394 | if (ret < 0) { | |
395 | rcu_read_unlock(); | |
396 | session_unlock_list(); | |
397 | /* | |
398 | * No notify thread, stop the UST tracing. However, this is | |
399 | * not an internal error of the this thread thus setting | |
400 | * the health error code to a normal exit. | |
401 | */ | |
402 | err = 0; | |
403 | goto error; | |
404 | } | |
405 | ||
406 | /* | |
407 | * Update newly registered application with the tracing | |
408 | * registry info already enabled information. | |
409 | */ | |
410 | update_ust_app(app->sock); | |
411 | ||
412 | /* | |
413 | * Don't care about return value. Let the manage apps threads | |
414 | * handle app unregistration upon socket close. | |
415 | */ | |
416 | (void) ust_app_register_done(app); | |
417 | ||
418 | /* | |
419 | * Even if the application socket has been closed, send the app | |
420 | * to the thread and unregistration will take place at that | |
421 | * place. | |
422 | */ | |
423 | ret = send_socket_to_thread( | |
424 | notifiers->apps_cmd_pipe_write_fd, | |
425 | app->sock); | |
426 | if (ret < 0) { | |
427 | rcu_read_unlock(); | |
428 | session_unlock_list(); | |
429 | /* | |
430 | * No apps. thread, stop the UST tracing. However, this is | |
431 | * not an internal error of the this thread thus setting | |
432 | * the health error code to a normal exit. | |
433 | */ | |
434 | err = 0; | |
435 | goto error; | |
436 | } | |
437 | ||
438 | rcu_read_unlock(); | |
439 | session_unlock_list(); | |
440 | } | |
441 | } while (node != NULL); | |
442 | ||
443 | health_poll_entry(); | |
444 | /* Futex wait on queue. Blocking call on futex() */ | |
445 | futex_nto1_wait(¬ifiers->ust_cmd_queue->futex); | |
446 | health_poll_exit(); | |
447 | } | |
448 | /* Normal exit, no error */ | |
449 | err = 0; | |
450 | ||
451 | error: | |
452 | /* Clean up wait queue. */ | |
453 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, | |
454 | &wait_queue.head, head) { | |
455 | cds_list_del(&wait_node->head); | |
456 | wait_queue.count--; | |
457 | free(wait_node); | |
458 | } | |
459 | ||
460 | /* Empty command queue. */ | |
461 | for (;;) { | |
462 | /* Dequeue command for registration */ | |
463 | node = cds_wfcq_dequeue_blocking( | |
464 | ¬ifiers->ust_cmd_queue->head, | |
465 | ¬ifiers->ust_cmd_queue->tail); | |
466 | if (node == NULL) { | |
467 | break; | |
468 | } | |
469 | ust_cmd = caa_container_of(node, struct ust_command, node); | |
470 | ret = close(ust_cmd->sock); | |
471 | if (ret < 0) { | |
472 | PERROR("close ust sock exit dispatch %d", ust_cmd->sock); | |
473 | } | |
474 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
475 | free(ust_cmd); | |
476 | } | |
477 | ||
478 | error_testpoint: | |
479 | DBG("Dispatch thread dying"); | |
480 | if (err) { | |
481 | health_error(); | |
482 | ERR("Health error occurred in %s", __func__); | |
483 | } | |
484 | health_unregister(health_sessiond); | |
485 | rcu_unregister_thread(); | |
486 | return NULL; | |
487 | } | |
488 | ||
489 | static bool shutdown_ust_dispatch_thread(void *data) | |
490 | { | |
491 | struct thread_notifiers *notifiers = data; | |
492 | ||
493 | CMM_STORE_SHARED(notifiers->dispatch_thread_exit, 1); | |
494 | futex_nto1_wake(¬ifiers->ust_cmd_queue->futex); | |
495 | return true; | |
496 | } | |
497 | ||
498 | bool launch_ust_dispatch_thread(struct ust_cmd_queue *cmd_queue, | |
499 | int apps_cmd_pipe_write_fd, | |
500 | int apps_cmd_notify_pipe_write_fd) | |
501 | { | |
502 | struct lttng_thread *thread; | |
503 | struct thread_notifiers *notifiers; | |
504 | ||
505 | notifiers = zmalloc(sizeof(*notifiers)); | |
506 | if (!notifiers) { | |
507 | goto error; | |
508 | } | |
509 | notifiers->ust_cmd_queue = cmd_queue; | |
510 | notifiers->apps_cmd_pipe_write_fd = apps_cmd_pipe_write_fd; | |
511 | notifiers->apps_cmd_notify_pipe_write_fd = apps_cmd_notify_pipe_write_fd; | |
512 | ||
513 | thread = lttng_thread_create("UST registration dispatch", | |
514 | thread_dispatch_ust_registration, | |
515 | shutdown_ust_dispatch_thread, | |
516 | cleanup_ust_dispatch_thread, | |
517 | notifiers); | |
518 | if (!thread) { | |
519 | goto error; | |
520 | } | |
521 | lttng_thread_put(thread); | |
522 | return true; | |
523 | error: | |
524 | free(notifiers); | |
525 | return false; | |
526 | } |