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); | |
88e3c2f5 | 54 | if (!sess->active || !sess->ust_session) { |
5d1b0219 JG |
55 | goto unlock_session; |
56 | } | |
57 | ||
58 | rcu_read_lock(); | |
59 | assert(app_sock >= 0); | |
60 | app = ust_app_find_by_sock(app_sock); | |
61 | if (app == NULL) { | |
62 | /* | |
63 | * Application can be unregistered before so | |
64 | * this is possible hence simply stopping the | |
65 | * update. | |
66 | */ | |
67 | DBG3("UST app update failed to find app sock %d", | |
68 | app_sock); | |
69 | goto unlock_rcu; | |
70 | } | |
71 | ust_app_global_update(sess->ust_session, app); | |
72 | unlock_rcu: | |
73 | rcu_read_unlock(); | |
74 | unlock_session: | |
75 | session_unlock(sess); | |
76 | session_put(sess); | |
77 | } | |
78 | } | |
79 | ||
80 | /* | |
81 | * Sanitize the wait queue of the dispatch registration thread meaning removing | |
82 | * invalid nodes from it. This is to avoid memory leaks for the case the UST | |
83 | * notify socket is never received. | |
84 | */ | |
85 | static void sanitize_wait_queue(struct ust_reg_wait_queue *wait_queue) | |
86 | { | |
87 | int ret, nb_fd = 0, i; | |
88 | unsigned int fd_added = 0; | |
89 | struct lttng_poll_event events; | |
90 | struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node; | |
91 | ||
92 | assert(wait_queue); | |
93 | ||
94 | lttng_poll_init(&events); | |
95 | ||
96 | /* Just skip everything for an empty queue. */ | |
97 | if (!wait_queue->count) { | |
98 | goto end; | |
99 | } | |
100 | ||
101 | ret = lttng_poll_create(&events, wait_queue->count, LTTNG_CLOEXEC); | |
102 | if (ret < 0) { | |
103 | goto error_create; | |
104 | } | |
105 | ||
106 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, | |
107 | &wait_queue->head, head) { | |
108 | assert(wait_node->app); | |
109 | ret = lttng_poll_add(&events, wait_node->app->sock, | |
110 | LPOLLHUP | LPOLLERR); | |
111 | if (ret < 0) { | |
112 | goto error; | |
113 | } | |
114 | ||
115 | fd_added = 1; | |
116 | } | |
117 | ||
118 | if (!fd_added) { | |
119 | goto end; | |
120 | } | |
121 | ||
122 | /* | |
123 | * Poll but don't block so we can quickly identify the faulty events and | |
124 | * clean them afterwards from the wait queue. | |
125 | */ | |
126 | ret = lttng_poll_wait(&events, 0); | |
127 | if (ret < 0) { | |
128 | goto error; | |
129 | } | |
130 | nb_fd = ret; | |
131 | ||
132 | for (i = 0; i < nb_fd; i++) { | |
133 | /* Get faulty FD. */ | |
134 | uint32_t revents = LTTNG_POLL_GETEV(&events, i); | |
135 | int pollfd = LTTNG_POLL_GETFD(&events, i); | |
136 | ||
5d1b0219 JG |
137 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, |
138 | &wait_queue->head, head) { | |
139 | if (pollfd == wait_node->app->sock && | |
140 | (revents & (LPOLLHUP | LPOLLERR))) { | |
141 | cds_list_del(&wait_node->head); | |
142 | wait_queue->count--; | |
143 | ust_app_destroy(wait_node->app); | |
144 | free(wait_node); | |
145 | /* | |
146 | * Silence warning of use-after-free in | |
147 | * cds_list_for_each_entry_safe which uses | |
148 | * __typeof__(*wait_node). | |
149 | */ | |
150 | wait_node = NULL; | |
151 | break; | |
152 | } else { | |
153 | ERR("Unexpected poll events %u for sock %d", revents, pollfd); | |
154 | goto error; | |
155 | } | |
156 | } | |
157 | } | |
158 | ||
159 | if (nb_fd > 0) { | |
160 | DBG("Wait queue sanitized, %d node were cleaned up", nb_fd); | |
161 | } | |
162 | ||
163 | end: | |
164 | lttng_poll_clean(&events); | |
165 | return; | |
166 | ||
167 | error: | |
168 | lttng_poll_clean(&events); | |
169 | error_create: | |
170 | ERR("Unable to sanitize wait queue"); | |
171 | return; | |
172 | } | |
173 | ||
174 | /* | |
175 | * Send a socket to a thread This is called from the dispatch UST registration | |
176 | * thread once all sockets are set for the application. | |
177 | * | |
178 | * The sock value can be invalid, we don't really care, the thread will handle | |
179 | * it and make the necessary cleanup if so. | |
180 | * | |
181 | * On success, return 0 else a negative value being the errno message of the | |
182 | * write(). | |
183 | */ | |
184 | static int send_socket_to_thread(int fd, int sock) | |
185 | { | |
186 | ssize_t ret; | |
187 | ||
188 | /* | |
189 | * It's possible that the FD is set as invalid with -1 concurrently just | |
190 | * before calling this function being a shutdown state of the thread. | |
191 | */ | |
192 | if (fd < 0) { | |
193 | ret = -EBADF; | |
194 | goto error; | |
195 | } | |
196 | ||
197 | ret = lttng_write(fd, &sock, sizeof(sock)); | |
198 | if (ret < sizeof(sock)) { | |
199 | PERROR("write apps pipe %d", fd); | |
200 | if (ret < 0) { | |
201 | ret = -errno; | |
202 | } | |
203 | goto error; | |
204 | } | |
205 | ||
206 | /* All good. Don't send back the write positive ret value. */ | |
207 | ret = 0; | |
208 | error: | |
209 | return (int) ret; | |
210 | } | |
211 | ||
212 | static void cleanup_ust_dispatch_thread(void *data) | |
213 | { | |
214 | free(data); | |
215 | } | |
216 | ||
217 | /* | |
218 | * Dispatch request from the registration threads to the application | |
219 | * communication thread. | |
220 | */ | |
221 | static void *thread_dispatch_ust_registration(void *data) | |
222 | { | |
223 | int ret, err = -1; | |
224 | struct cds_wfcq_node *node; | |
225 | struct ust_command *ust_cmd = NULL; | |
226 | struct ust_reg_wait_node *wait_node = NULL, *tmp_wait_node; | |
227 | struct ust_reg_wait_queue wait_queue = { | |
228 | .count = 0, | |
229 | }; | |
230 | struct thread_notifiers *notifiers = data; | |
231 | ||
232 | rcu_register_thread(); | |
233 | ||
234 | health_register(health_sessiond, HEALTH_SESSIOND_TYPE_APP_REG_DISPATCH); | |
235 | ||
236 | if (testpoint(sessiond_thread_app_reg_dispatch)) { | |
237 | goto error_testpoint; | |
238 | } | |
239 | ||
240 | health_code_update(); | |
241 | ||
242 | CDS_INIT_LIST_HEAD(&wait_queue.head); | |
243 | ||
244 | DBG("[thread] Dispatch UST command started"); | |
245 | ||
246 | for (;;) { | |
247 | health_code_update(); | |
248 | ||
249 | /* Atomically prepare the queue futex */ | |
250 | futex_nto1_prepare(¬ifiers->ust_cmd_queue->futex); | |
251 | ||
252 | if (CMM_LOAD_SHARED(notifiers->dispatch_thread_exit)) { | |
253 | break; | |
254 | } | |
255 | ||
256 | do { | |
257 | struct ust_app *app = NULL; | |
258 | ust_cmd = NULL; | |
259 | ||
260 | /* | |
261 | * Make sure we don't have node(s) that have hung up before receiving | |
262 | * the notify socket. This is to clean the list in order to avoid | |
263 | * memory leaks from notify socket that are never seen. | |
264 | */ | |
265 | sanitize_wait_queue(&wait_queue); | |
266 | ||
267 | health_code_update(); | |
268 | /* Dequeue command for registration */ | |
269 | node = cds_wfcq_dequeue_blocking( | |
270 | ¬ifiers->ust_cmd_queue->head, | |
271 | ¬ifiers->ust_cmd_queue->tail); | |
272 | if (node == NULL) { | |
273 | DBG("Woken up but nothing in the UST command queue"); | |
274 | /* Continue thread execution */ | |
275 | break; | |
276 | } | |
277 | ||
278 | ust_cmd = caa_container_of(node, struct ust_command, node); | |
279 | ||
280 | DBG("Dispatching UST registration pid:%d ppid:%d uid:%d" | |
281 | " gid:%d sock:%d name:%s (version %d.%d)", | |
282 | ust_cmd->reg_msg.pid, ust_cmd->reg_msg.ppid, | |
283 | ust_cmd->reg_msg.uid, ust_cmd->reg_msg.gid, | |
284 | ust_cmd->sock, ust_cmd->reg_msg.name, | |
285 | ust_cmd->reg_msg.major, ust_cmd->reg_msg.minor); | |
286 | ||
287 | if (ust_cmd->reg_msg.type == USTCTL_SOCKET_CMD) { | |
288 | wait_node = zmalloc(sizeof(*wait_node)); | |
289 | if (!wait_node) { | |
290 | PERROR("zmalloc wait_node dispatch"); | |
291 | ret = close(ust_cmd->sock); | |
292 | if (ret < 0) { | |
293 | PERROR("close ust sock dispatch %d", ust_cmd->sock); | |
294 | } | |
295 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
296 | free(ust_cmd); | |
58f835e1 | 297 | ust_cmd = NULL; |
5d1b0219 JG |
298 | goto error; |
299 | } | |
300 | CDS_INIT_LIST_HEAD(&wait_node->head); | |
301 | ||
302 | /* Create application object if socket is CMD. */ | |
303 | wait_node->app = ust_app_create(&ust_cmd->reg_msg, | |
304 | ust_cmd->sock); | |
305 | if (!wait_node->app) { | |
306 | ret = close(ust_cmd->sock); | |
307 | if (ret < 0) { | |
308 | PERROR("close ust sock dispatch %d", ust_cmd->sock); | |
309 | } | |
310 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
311 | free(wait_node); | |
58f835e1 | 312 | wait_node = NULL; |
5d1b0219 | 313 | free(ust_cmd); |
58f835e1 | 314 | ust_cmd = NULL; |
5d1b0219 JG |
315 | continue; |
316 | } | |
317 | /* | |
318 | * Add application to the wait queue so we can set the notify | |
319 | * socket before putting this object in the global ht. | |
320 | */ | |
321 | cds_list_add(&wait_node->head, &wait_queue.head); | |
322 | wait_queue.count++; | |
323 | ||
324 | free(ust_cmd); | |
58f835e1 | 325 | ust_cmd = NULL; |
5d1b0219 JG |
326 | /* |
327 | * We have to continue here since we don't have the notify | |
328 | * socket and the application MUST be added to the hash table | |
329 | * only at that moment. | |
330 | */ | |
331 | continue; | |
332 | } else { | |
333 | /* | |
334 | * Look for the application in the local wait queue and set the | |
335 | * notify socket if found. | |
336 | */ | |
337 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, | |
338 | &wait_queue.head, head) { | |
339 | health_code_update(); | |
340 | if (wait_node->app->pid == ust_cmd->reg_msg.pid) { | |
341 | wait_node->app->notify_sock = ust_cmd->sock; | |
342 | cds_list_del(&wait_node->head); | |
343 | wait_queue.count--; | |
344 | app = wait_node->app; | |
345 | free(wait_node); | |
58f835e1 | 346 | wait_node = NULL; |
5d1b0219 JG |
347 | DBG3("UST app notify socket %d is set", ust_cmd->sock); |
348 | break; | |
349 | } | |
350 | } | |
351 | ||
352 | /* | |
353 | * With no application at this stage the received socket is | |
354 | * basically useless so close it before we free the cmd data | |
355 | * structure for good. | |
356 | */ | |
357 | if (!app) { | |
358 | ret = close(ust_cmd->sock); | |
359 | if (ret < 0) { | |
360 | PERROR("close ust sock dispatch %d", ust_cmd->sock); | |
361 | } | |
362 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
363 | } | |
364 | free(ust_cmd); | |
58f835e1 | 365 | ust_cmd = NULL; |
5d1b0219 JG |
366 | } |
367 | ||
368 | if (app) { | |
369 | /* | |
370 | * @session_lock_list | |
371 | * | |
372 | * Lock the global session list so from the register up to the | |
373 | * registration done message, no thread can see the application | |
374 | * and change its state. | |
375 | */ | |
376 | session_lock_list(); | |
377 | rcu_read_lock(); | |
378 | ||
379 | /* | |
380 | * Add application to the global hash table. This needs to be | |
381 | * done before the update to the UST registry can locate the | |
382 | * application. | |
383 | */ | |
384 | ust_app_add(app); | |
385 | ||
386 | /* Set app version. This call will print an error if needed. */ | |
387 | (void) ust_app_version(app); | |
388 | ||
389 | /* Send notify socket through the notify pipe. */ | |
390 | ret = send_socket_to_thread( | |
391 | notifiers->apps_cmd_notify_pipe_write_fd, | |
392 | app->notify_sock); | |
393 | if (ret < 0) { | |
394 | rcu_read_unlock(); | |
395 | session_unlock_list(); | |
396 | /* | |
397 | * No notify thread, stop the UST tracing. However, this is | |
398 | * not an internal error of the this thread thus setting | |
399 | * the health error code to a normal exit. | |
400 | */ | |
401 | err = 0; | |
402 | goto error; | |
403 | } | |
404 | ||
405 | /* | |
406 | * Update newly registered application with the tracing | |
407 | * registry info already enabled information. | |
408 | */ | |
409 | update_ust_app(app->sock); | |
410 | ||
411 | /* | |
412 | * Don't care about return value. Let the manage apps threads | |
413 | * handle app unregistration upon socket close. | |
414 | */ | |
415 | (void) ust_app_register_done(app); | |
416 | ||
417 | /* | |
418 | * Even if the application socket has been closed, send the app | |
419 | * to the thread and unregistration will take place at that | |
420 | * place. | |
421 | */ | |
422 | ret = send_socket_to_thread( | |
423 | notifiers->apps_cmd_pipe_write_fd, | |
424 | app->sock); | |
425 | if (ret < 0) { | |
426 | rcu_read_unlock(); | |
427 | session_unlock_list(); | |
428 | /* | |
429 | * No apps. thread, stop the UST tracing. However, this is | |
430 | * not an internal error of the this thread thus setting | |
431 | * the health error code to a normal exit. | |
432 | */ | |
433 | err = 0; | |
434 | goto error; | |
435 | } | |
436 | ||
437 | rcu_read_unlock(); | |
438 | session_unlock_list(); | |
439 | } | |
440 | } while (node != NULL); | |
441 | ||
442 | health_poll_entry(); | |
443 | /* Futex wait on queue. Blocking call on futex() */ | |
444 | futex_nto1_wait(¬ifiers->ust_cmd_queue->futex); | |
445 | health_poll_exit(); | |
446 | } | |
447 | /* Normal exit, no error */ | |
448 | err = 0; | |
449 | ||
450 | error: | |
451 | /* Clean up wait queue. */ | |
452 | cds_list_for_each_entry_safe(wait_node, tmp_wait_node, | |
453 | &wait_queue.head, head) { | |
454 | cds_list_del(&wait_node->head); | |
455 | wait_queue.count--; | |
456 | free(wait_node); | |
457 | } | |
458 | ||
459 | /* Empty command queue. */ | |
460 | for (;;) { | |
461 | /* Dequeue command for registration */ | |
462 | node = cds_wfcq_dequeue_blocking( | |
463 | ¬ifiers->ust_cmd_queue->head, | |
464 | ¬ifiers->ust_cmd_queue->tail); | |
465 | if (node == NULL) { | |
466 | break; | |
467 | } | |
468 | ust_cmd = caa_container_of(node, struct ust_command, node); | |
469 | ret = close(ust_cmd->sock); | |
470 | if (ret < 0) { | |
471 | PERROR("close ust sock exit dispatch %d", ust_cmd->sock); | |
472 | } | |
473 | lttng_fd_put(LTTNG_FD_APPS, 1); | |
474 | free(ust_cmd); | |
475 | } | |
476 | ||
477 | error_testpoint: | |
478 | DBG("Dispatch thread dying"); | |
479 | if (err) { | |
480 | health_error(); | |
481 | ERR("Health error occurred in %s", __func__); | |
482 | } | |
483 | health_unregister(health_sessiond); | |
484 | rcu_unregister_thread(); | |
485 | return NULL; | |
486 | } | |
487 | ||
488 | static bool shutdown_ust_dispatch_thread(void *data) | |
489 | { | |
490 | struct thread_notifiers *notifiers = data; | |
491 | ||
492 | CMM_STORE_SHARED(notifiers->dispatch_thread_exit, 1); | |
493 | futex_nto1_wake(¬ifiers->ust_cmd_queue->futex); | |
494 | return true; | |
495 | } | |
496 | ||
497 | bool launch_ust_dispatch_thread(struct ust_cmd_queue *cmd_queue, | |
498 | int apps_cmd_pipe_write_fd, | |
499 | int apps_cmd_notify_pipe_write_fd) | |
500 | { | |
501 | struct lttng_thread *thread; | |
502 | struct thread_notifiers *notifiers; | |
503 | ||
504 | notifiers = zmalloc(sizeof(*notifiers)); | |
505 | if (!notifiers) { | |
506 | goto error; | |
507 | } | |
508 | notifiers->ust_cmd_queue = cmd_queue; | |
509 | notifiers->apps_cmd_pipe_write_fd = apps_cmd_pipe_write_fd; | |
510 | notifiers->apps_cmd_notify_pipe_write_fd = apps_cmd_notify_pipe_write_fd; | |
511 | ||
512 | thread = lttng_thread_create("UST registration dispatch", | |
513 | thread_dispatch_ust_registration, | |
514 | shutdown_ust_dispatch_thread, | |
515 | cleanup_ust_dispatch_thread, | |
516 | notifiers); | |
517 | if (!thread) { | |
518 | goto error; | |
519 | } | |
520 | lttng_thread_put(thread); | |
521 | return true; | |
522 | error: | |
523 | free(notifiers); | |
524 | return false; | |
525 | } |