043993a60484130450dbe3dd75818b72ea9f4b66
[lttng-tools.git] / src / bin / lttng-sessiond / rotation-thread.c
1 /*
2 * Copyright (C) 2017 - Julien Desfossez <jdesfossez@efficios.com>
3 * Copyright (C) 2018 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License, version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc., 51
16 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19 #define _LGPL_SOURCE
20 #include <lttng/trigger/trigger.h>
21 #include <common/error.h>
22 #include <common/config/session-config.h>
23 #include <common/defaults.h>
24 #include <common/utils.h>
25 #include <common/futex.h>
26 #include <common/align.h>
27 #include <common/time.h>
28 #include <common/hashtable/utils.h>
29 #include <sys/eventfd.h>
30 #include <sys/stat.h>
31 #include <time.h>
32 #include <signal.h>
33 #include <inttypes.h>
34
35 #include <common/kernel-ctl/kernel-ctl.h>
36 #include <lttng/notification/channel-internal.h>
37 #include <lttng/rotate-internal.h>
38
39 #include "rotation-thread.h"
40 #include "lttng-sessiond.h"
41 #include "health-sessiond.h"
42 #include "rotate.h"
43 #include "cmd.h"
44 #include "session.h"
45 #include "timer.h"
46 #include "notification-thread-commands.h"
47
48 #include <urcu.h>
49 #include <urcu/list.h>
50
51 struct lttng_notification_channel *rotate_notification_channel = NULL;
52
53 struct rotation_thread {
54 struct lttng_poll_event events;
55 };
56
57 struct rotation_thread_job {
58 enum rotation_thread_job_type type;
59 struct ltt_session *session;
60 /* List member in struct rotation_thread_timer_queue. */
61 struct cds_list_head head;
62 };
63
64 /*
65 * The timer thread enqueues jobs and wakes up the rotation thread.
66 * When the rotation thread wakes up, it empties the queue.
67 */
68 struct rotation_thread_timer_queue {
69 struct lttng_pipe *event_pipe;
70 struct cds_list_head list;
71 pthread_mutex_t lock;
72 };
73
74 struct rotation_thread_handle {
75 struct rotation_thread_timer_queue *rotation_timer_queue;
76 /* Access to the notification thread cmd_queue */
77 struct notification_thread_handle *notification_thread_handle;
78 };
79
80 static
81 const char *get_job_type_str(enum rotation_thread_job_type job_type)
82 {
83 switch (job_type) {
84 case ROTATION_THREAD_JOB_TYPE_CHECK_PENDING_ROTATION:
85 return "CHECK_PENDING_ROTATION";
86 case ROTATION_THREAD_JOB_TYPE_SCHEDULED_ROTATION:
87 return "SCHEDULED_ROTATION";
88 default:
89 abort();
90 }
91 }
92
93 struct rotation_thread_timer_queue *rotation_thread_timer_queue_create(void)
94 {
95 struct rotation_thread_timer_queue *queue = NULL;
96
97 queue = zmalloc(sizeof(*queue));
98 if (!queue) {
99 PERROR("Failed to allocate timer rotate queue");
100 goto end;
101 }
102
103 queue->event_pipe = lttng_pipe_open(FD_CLOEXEC | O_NONBLOCK);
104 CDS_INIT_LIST_HEAD(&queue->list);
105 pthread_mutex_init(&queue->lock, NULL);
106 end:
107 return queue;
108 }
109
110 void log_job_destruction(const struct rotation_thread_job *job)
111 {
112 enum lttng_error_level log_level;
113 const char *job_type_str = get_job_type_str(job->type);
114
115 switch (job->type) {
116 case ROTATION_THREAD_JOB_TYPE_SCHEDULED_ROTATION:
117 /*
118 * Not a problem, the scheduled rotation is racing with the teardown
119 * of the daemon. In this case, the rotation will not happen, which
120 * is not a problem (or at least, not important enough to delay
121 * the shutdown of the session daemon).
122 */
123 log_level = PRINT_DBG;
124 break;
125 case ROTATION_THREAD_JOB_TYPE_CHECK_PENDING_ROTATION:
126 /* This is not expected to happen; warn the user. */
127 log_level = PRINT_WARN;
128 break;
129 default:
130 abort();
131 }
132
133 LOG(log_level, "Rotation thread timer queue still contains job of type %s targeting session \"%s\" on destruction",
134 job_type_str, job->session->name);
135 }
136
137 void rotation_thread_timer_queue_destroy(
138 struct rotation_thread_timer_queue *queue)
139 {
140 struct rotation_thread_job *job, *tmp_job;
141
142 if (!queue) {
143 return;
144 }
145
146 lttng_pipe_destroy(queue->event_pipe);
147
148 pthread_mutex_lock(&queue->lock);
149 /* Empty wait queue. */
150 cds_list_for_each_entry_safe(job, tmp_job, &queue->list, head) {
151 log_job_destruction(job);
152 cds_list_del(&job->head);
153 free(job);
154 }
155 pthread_mutex_unlock(&queue->lock);
156 pthread_mutex_destroy(&queue->lock);
157 free(queue);
158 }
159
160 /*
161 * Destroy the thread data previously created by the init function.
162 */
163 void rotation_thread_handle_destroy(
164 struct rotation_thread_handle *handle)
165 {
166 free(handle);
167 }
168
169 struct rotation_thread_handle *rotation_thread_handle_create(
170 struct rotation_thread_timer_queue *rotation_timer_queue,
171 struct notification_thread_handle *notification_thread_handle)
172 {
173 struct rotation_thread_handle *handle;
174
175 handle = zmalloc(sizeof(*handle));
176 if (!handle) {
177 goto end;
178 }
179
180 handle->rotation_timer_queue = rotation_timer_queue;
181 handle->notification_thread_handle = notification_thread_handle;
182
183 end:
184 return handle;
185 }
186
187 /*
188 * Called with the rotation_thread_timer_queue lock held.
189 * Return true if the same timer job already exists in the queue, false if not.
190 */
191 static
192 bool timer_job_exists(const struct rotation_thread_timer_queue *queue,
193 enum rotation_thread_job_type job_type,
194 struct ltt_session *session)
195 {
196 bool exists = false;
197 struct rotation_thread_job *job;
198
199 cds_list_for_each_entry(job, &queue->list, head) {
200 if (job->session == session && job->type == job_type) {
201 exists = true;
202 goto end;
203 }
204 }
205 end:
206 return exists;
207 }
208
209 void rotation_thread_enqueue_job(struct rotation_thread_timer_queue *queue,
210 enum rotation_thread_job_type job_type,
211 struct ltt_session *session)
212 {
213 int ret;
214 const char * const dummy = "!";
215 struct rotation_thread_job *job = NULL;
216 const char *job_type_str = get_job_type_str(job_type);
217
218 pthread_mutex_lock(&queue->lock);
219 if (timer_job_exists(queue, job_type, session)) {
220 /*
221 * This timer job is already pending, we don't need to add
222 * it.
223 */
224 goto end;
225 }
226
227 job = zmalloc(sizeof(struct rotation_thread_job));
228 if (!job) {
229 PERROR("Failed to allocate rotation thread job of type \"%s\" for session \"%s\"",
230 job_type_str, session->name);
231 goto end;
232 }
233 /* No reason for this to fail as the caller must hold a reference. */
234 (void) session_get(session);
235
236 job->session = session;
237 job->type = job_type;
238 cds_list_add_tail(&job->head, &queue->list);
239
240 ret = lttng_write(lttng_pipe_get_writefd(queue->event_pipe), dummy,
241 1);
242 if (ret < 0) {
243 /*
244 * We do not want to block in the timer handler, the job has
245 * been enqueued in the list, the wakeup pipe is probably full,
246 * the job will be processed when the rotation_thread catches
247 * up.
248 */
249 if (errno == EAGAIN || errno == EWOULDBLOCK) {
250 /*
251 * Not an error, but would be surprising and indicate
252 * that the rotation thread can't keep up with the
253 * current load.
254 */
255 DBG("Wake-up pipe of rotation thread job queue is full");
256 goto end;
257 }
258 PERROR("Failed to wake-up the rotation thread after pushing a job of type \"%s\" for session \"%s\"",
259 job_type_str, session->name);
260 goto end;
261 }
262
263 end:
264 pthread_mutex_unlock(&queue->lock);
265 }
266
267 static
268 int init_poll_set(struct lttng_poll_event *poll_set,
269 struct rotation_thread_handle *handle)
270 {
271 int ret;
272
273 /*
274 * Create pollset with size 2:
275 * - quit pipe,
276 * - rotation thread timer queue pipe,
277 */
278 ret = sessiond_set_thread_pollset(poll_set, 2);
279 if (ret) {
280 goto error;
281 }
282 ret = lttng_poll_add(poll_set,
283 lttng_pipe_get_readfd(handle->rotation_timer_queue->event_pipe),
284 LPOLLIN | LPOLLERR);
285 if (ret < 0) {
286 ERR("[rotation-thread] Failed to add rotate_pending fd to pollset");
287 goto error;
288 }
289
290 return ret;
291 error:
292 lttng_poll_clean(poll_set);
293 return ret;
294 }
295
296 static
297 void fini_thread_state(struct rotation_thread *state)
298 {
299 lttng_poll_clean(&state->events);
300 if (rotate_notification_channel) {
301 lttng_notification_channel_destroy(rotate_notification_channel);
302 }
303 }
304
305 static
306 int init_thread_state(struct rotation_thread_handle *handle,
307 struct rotation_thread *state)
308 {
309 int ret;
310
311 memset(state, 0, sizeof(*state));
312 lttng_poll_init(&state->events);
313
314 ret = init_poll_set(&state->events, handle);
315 if (ret) {
316 ERR("[rotation-thread] Failed to initialize rotation thread poll set");
317 goto end;
318 }
319
320 rotate_notification_channel = lttng_notification_channel_create(
321 lttng_session_daemon_notification_endpoint);
322 if (!rotate_notification_channel) {
323 ERR("[rotation-thread] Could not create notification channel");
324 ret = -1;
325 goto end;
326 }
327 ret = lttng_poll_add(&state->events, rotate_notification_channel->socket,
328 LPOLLIN | LPOLLERR);
329 if (ret < 0) {
330 ERR("[rotation-thread] Failed to add notification fd to pollset");
331 goto end;
332 }
333
334 end:
335 return ret;
336 }
337
338 static
339 int check_session_rotation_pending_local_on_consumer(
340 const struct ltt_session *session,
341 struct consumer_socket *socket, bool *rotation_completed)
342 {
343 int ret;
344
345 pthread_mutex_lock(socket->lock);
346 DBG("[rotation-thread] Checking for locally pending rotation on the %s consumer for session %s",
347 lttng_consumer_type_str(socket->type),
348 session->name);
349 ret = consumer_check_rotation_pending_local(socket,
350 session->id,
351 session->current_archive_id - 1);
352 pthread_mutex_unlock(socket->lock);
353
354 if (ret == 0) {
355 /* Rotation was completed on this consumer. */
356 DBG("[rotation-thread] Local rotation of trace archive %" PRIu64 " of session \"%s\" was completed on the %s consumer",
357 session->current_archive_id - 1,
358 session->name,
359 lttng_consumer_type_str(socket->type));
360 *rotation_completed = true;
361 } else if (ret == 1) {
362 /* Rotation pending on this consumer. */
363 DBG("[rotation-thread] Local rotation of trace archive %" PRIu64 " of session \"%s\" is pending on the %s consumer",
364 session->current_archive_id - 1,
365 session->name,
366 lttng_consumer_type_str(socket->type));
367 *rotation_completed = false;
368 ret = 0;
369 } else {
370 /* Not a fatal error. */
371 ERR("[rotation-thread] Encountered an error when checking if local rotation of trace archive %" PRIu64 " of session \"%s\" is pending on the %s consumer",
372 session->current_archive_id - 1,
373 session->name,
374 lttng_consumer_type_str(socket->type));
375 *rotation_completed = false;
376 }
377 return ret;
378 }
379
380 static
381 int check_session_rotation_pending_local(struct ltt_session *session)
382 {
383 int ret = 0;
384 struct consumer_socket *socket;
385 struct cds_lfht_iter iter;
386 bool rotation_completed = true;
387
388 /*
389 * Check for a local pending rotation on all consumers (32-bit
390 * user space, 64-bit user space, and kernel).
391 */
392 DBG("[rotation-thread] Checking for pending local rotation on session \"%s\", trace archive %" PRIu64,
393 session->name, session->current_archive_id - 1);
394
395 rcu_read_lock();
396 if (!session->ust_session) {
397 goto skip_ust;
398 }
399 cds_lfht_for_each_entry(session->ust_session->consumer->socks->ht,
400 &iter, socket, node.node) {
401 ret = check_session_rotation_pending_local_on_consumer(session,
402 socket, &rotation_completed);
403 if (ret || !rotation_completed) {
404 goto end;
405 }
406 }
407
408 skip_ust:
409 if (!session->kernel_session) {
410 goto skip_kernel;
411 }
412 cds_lfht_for_each_entry(session->kernel_session->consumer->socks->ht,
413 &iter, socket, node.node) {
414 ret = check_session_rotation_pending_local_on_consumer(session,
415 socket, &rotation_completed);
416 if (ret || !rotation_completed) {
417 goto end;
418 }
419 }
420 skip_kernel:
421 end:
422 rcu_read_unlock();
423
424 if (rotation_completed) {
425 DBG("[rotation-thread] Local rotation of trace archive %" PRIu64 " of session \"%s\" is complete on all consumers",
426 session->current_archive_id - 1,
427 session->name);
428 session->rotation_pending_local = false;
429 }
430 if (ret) {
431 ret = session_reset_rotation_state(session,
432 LTTNG_ROTATION_STATE_ERROR);
433 if (ret) {
434 ERR("Failed to reset rotation state of session \"%s\"",
435 session->name);
436 }
437 }
438 return 0;
439 }
440
441 static
442 int check_session_rotation_pending_relay(struct ltt_session *session)
443 {
444 int ret;
445 struct consumer_socket *socket;
446 struct cds_lfht_iter iter;
447 bool rotation_completed = true;
448 const struct consumer_output *output;
449
450 /*
451 * Check for a pending rotation on any consumer as we only use
452 * it as a "tunnel" to the relayd.
453 */
454
455 rcu_read_lock();
456 if (session->ust_session) {
457 cds_lfht_first(session->ust_session->consumer->socks->ht,
458 &iter);
459 output = session->ust_session->consumer;
460 } else {
461 cds_lfht_first(session->kernel_session->consumer->socks->ht,
462 &iter);
463 output = session->kernel_session->consumer;
464 }
465 assert(cds_lfht_iter_get_node(&iter));
466
467 socket = caa_container_of(cds_lfht_iter_get_node(&iter),
468 typeof(*socket), node.node);
469
470 pthread_mutex_lock(socket->lock);
471 DBG("[rotation-thread] Checking for pending relay rotation on session \"%s\", trace archive %" PRIu64 " through the %s consumer",
472 session->name, session->current_archive_id - 1,
473 lttng_consumer_type_str(socket->type));
474 ret = consumer_check_rotation_pending_relay(socket,
475 output,
476 session->id,
477 session->current_archive_id - 1);
478 pthread_mutex_unlock(socket->lock);
479
480 if (ret == 0) {
481 /* Rotation was completed on the relay. */
482 DBG("[rotation-thread] Relay rotation of trace archive %" PRIu64 " of session \"%s\" was completed",
483 session->current_archive_id - 1,
484 session->name);
485 } else if (ret == 1) {
486 /* Rotation pending on relay. */
487 DBG("[rotation-thread] Relay rotation of trace archive %" PRIu64 " of session \"%s\" is pending",
488 session->current_archive_id - 1,
489 session->name);
490 rotation_completed = false;
491 } else {
492 /* Not a fatal error. */
493 ERR("[rotation-thread] Encountered an error when checking if rotation of trace archive %" PRIu64 " of session \"%s\" is pending on the relay",
494 session->current_archive_id - 1,
495 session->name);
496 ret = session_reset_rotation_state(session,
497 LTTNG_ROTATION_STATE_ERROR);
498 if (ret) {
499 ERR("Failed to reset rotation state of session \"%s\"",
500 session->name);
501 }
502 rotation_completed = false;
503 }
504
505 rcu_read_unlock();
506
507 if (rotation_completed) {
508 DBG("[rotation-thread] Rotation of trace archive %" PRIu64 " of session \"%s\" is complete on the relay",
509 session->current_archive_id - 1,
510 session->name);
511 session->rotation_pending_relay = false;
512 }
513 return 0;
514 }
515
516 /*
517 * Check if the last rotation was completed, called with session lock held.
518 */
519 static
520 int check_session_rotation_pending(struct ltt_session *session,
521 struct notification_thread_handle *notification_thread_handle)
522 {
523 int ret;
524 struct lttng_trace_archive_location *location;
525 time_t now;
526
527 DBG("[rotation-thread] Checking for pending rotation on session \"%s\", trace archive %" PRIu64,
528 session->name, session->current_archive_id - 1);
529
530 /*
531 * The rotation-pending check timer of a session is launched in
532 * one-shot mode. If the rotation is incomplete, the rotation
533 * thread will re-enable the pending-check timer.
534 *
535 * The timer thread can't stop the timer itself since it is involved
536 * in the check for the timer's quiescence.
537 */
538 ret = timer_session_rotation_pending_check_stop(session);
539 if (ret) {
540 goto end;
541 }
542
543 if (session->rotation_pending_local) {
544 /* Updates session->rotation_pending_local as needed. */
545 ret = check_session_rotation_pending_local(session);
546 if (ret) {
547 goto end;
548 }
549
550 /*
551 * No need to check for a pending rotation on the relay
552 * since the rotation is not even completed locally yet.
553 */
554 if (session->rotation_pending_local) {
555 goto end;
556 }
557 }
558
559 if (session->rotation_pending_relay) {
560 /* Updates session->rotation_pending_relay as needed. */
561 ret = check_session_rotation_pending_relay(session);
562 if (ret) {
563 goto end;
564 }
565
566 if (session->rotation_pending_relay) {
567 goto end;
568 }
569 }
570
571 DBG("[rotation-thread] Rotation of trace archive %" PRIu64 " completed for "
572 "session %s", session->current_archive_id - 1,
573 session->name);
574
575 /* Rename the completed trace archive's location. */
576 now = time(NULL);
577 if (now == (time_t) -1) {
578 ret = session_reset_rotation_state(session,
579 LTTNG_ROTATION_STATE_ERROR);
580 if (ret) {
581 ERR("Failed to reset rotation state of session \"%s\"",
582 session->name);
583 }
584 ret = LTTNG_ERR_UNK;
585 goto end;
586 }
587
588 ret = rename_completed_chunk(session, now);
589 if (ret < 0) {
590 ERR("Failed to rename completed rotation chunk");
591 goto end;
592 }
593 session->last_chunk_start_ts = session->current_chunk_start_ts;
594
595 /*
596 * Now we can clear the "ONGOING" state in the session. New
597 * rotations can start now.
598 */
599 session->rotation_state = LTTNG_ROTATION_STATE_COMPLETED;
600
601 /* Ownership of location is transferred. */
602 location = session_get_trace_archive_location(session);
603 ret = notification_thread_command_session_rotation_completed(
604 notification_thread_handle,
605 session->name,
606 session->uid,
607 session->gid,
608 session->current_archive_id,
609 location);
610 if (ret != LTTNG_OK) {
611 ERR("[rotation-thread] Failed to notify notification thread of completed rotation for session %s",
612 session->name);
613 }
614
615 if (!session->active) {
616 /*
617 * A stop command was issued during the rotation, it is
618 * up to the rotation completion check to perform the
619 * renaming of the last chunk that was produced.
620 */
621 ret = notification_thread_command_session_rotation_ongoing(
622 notification_thread_handle,
623 session->name,
624 session->uid,
625 session->gid,
626 session->current_archive_id);
627 if (ret != LTTNG_OK) {
628 ERR("[rotation-thread] Failed to notify notification thread of completed rotation for session %s",
629 session->name);
630 }
631
632 ret = rename_active_chunk(session);
633 if (ret < 0) {
634 ERR("[rotation-thread] Failed to rename active rotation chunk");
635 goto end;
636 }
637
638 /* Ownership of location is transferred. */
639 location = session_get_trace_archive_location(session);
640 ret = notification_thread_command_session_rotation_completed(
641 notification_thread_handle,
642 session->name,
643 session->uid,
644 session->gid,
645 session->current_archive_id,
646 location);
647 if (ret != LTTNG_OK) {
648 ERR("[rotation-thread] Failed to notify notification thread of completed rotation for session %s",
649 session->name);
650 }
651 }
652
653 ret = 0;
654 end:
655 if (session->rotation_state == LTTNG_ROTATION_STATE_ONGOING) {
656 DBG("[rotation-thread] Rotation of trace archive %" PRIu64 " is still pending for session %s",
657 session->current_archive_id - 1, session->name);
658 ret = timer_session_rotation_pending_check_start(session,
659 DEFAULT_ROTATE_PENDING_TIMER);
660 if (ret) {
661 ERR("Re-enabling rotate pending timer");
662 ret = -1;
663 goto end;
664 }
665 }
666
667 return ret;
668 }
669
670 /* Call with the session and session_list locks held. */
671 static
672 int launch_session_rotation(struct ltt_session *session)
673 {
674 int ret;
675 struct lttng_rotate_session_return rotation_return;
676
677 DBG("[rotation-thread] Launching scheduled time-based rotation on session \"%s\"",
678 session->name);
679
680 ret = cmd_rotate_session(session, &rotation_return);
681 if (ret == LTTNG_OK) {
682 DBG("[rotation-thread] Scheduled time-based rotation successfully launched on session \"%s\"",
683 session->name);
684 } else {
685 /* Don't consider errors as fatal. */
686 DBG("[rotation-thread] Scheduled time-based rotation aborted for session %s: %s",
687 session->name, lttng_strerror(ret));
688 }
689 return 0;
690 }
691
692 static
693 int run_job(struct rotation_thread_job *job, struct ltt_session *session,
694 struct notification_thread_handle *notification_thread_handle)
695 {
696 int ret;
697
698 switch (job->type) {
699 case ROTATION_THREAD_JOB_TYPE_SCHEDULED_ROTATION:
700 ret = launch_session_rotation(session);
701 break;
702 case ROTATION_THREAD_JOB_TYPE_CHECK_PENDING_ROTATION:
703 ret = check_session_rotation_pending(session,
704 notification_thread_handle);
705 break;
706 default:
707 abort();
708 }
709 return ret;
710 }
711
712 static
713 int handle_job_queue(struct rotation_thread_handle *handle,
714 struct rotation_thread *state,
715 struct rotation_thread_timer_queue *queue)
716 {
717 int ret = 0;
718
719 for (;;) {
720 struct ltt_session *session;
721 struct rotation_thread_job *job;
722
723 /* Take the queue lock only to pop an element from the list. */
724 pthread_mutex_lock(&queue->lock);
725 if (cds_list_empty(&queue->list)) {
726 pthread_mutex_unlock(&queue->lock);
727 break;
728 }
729 job = cds_list_first_entry(&queue->list,
730 typeof(*job), head);
731 cds_list_del(&job->head);
732 pthread_mutex_unlock(&queue->lock);
733
734 session_lock_list();
735 session = job->session;
736 if (!session) {
737 DBG("[rotation-thread] Session \"%s\" not found",
738 session->name);
739 /*
740 * This is a non-fatal error, and we cannot report it to
741 * the user (timer), so just print the error and
742 * continue the processing.
743 *
744 * While the timer thread will purge pending signals for
745 * a session on the session's destruction, it is
746 * possible for a job targeting that session to have
747 * already been queued before it was destroyed.
748 */
749 session_unlock_list();
750 free(job);
751 session_put(session);
752 continue;
753 }
754
755 session_lock(session);
756 ret = run_job(job, session, handle->notification_thread_handle);
757 session_unlock(session);
758 /* Release reference held by the job. */
759 session_put(session);
760 session_unlock_list();
761 free(job);
762 if (ret) {
763 goto end;
764 }
765 }
766
767 ret = 0;
768
769 end:
770 return ret;
771 }
772
773 static
774 int handle_condition(const struct lttng_condition *condition,
775 const struct lttng_evaluation *evaluation,
776 struct notification_thread_handle *notification_thread_handle)
777 {
778 int ret = 0;
779 const char *condition_session_name = NULL;
780 enum lttng_condition_type condition_type;
781 enum lttng_condition_status condition_status;
782 enum lttng_evaluation_status evaluation_status;
783 uint64_t consumed;
784 struct ltt_session *session;
785
786 condition_type = lttng_condition_get_type(condition);
787
788 if (condition_type != LTTNG_CONDITION_TYPE_SESSION_CONSUMED_SIZE) {
789 ret = -1;
790 ERR("[rotation-thread] Condition type and session usage type are not the same");
791 goto end;
792 }
793
794 /* Fetch info to test */
795 condition_status = lttng_condition_session_consumed_size_get_session_name(
796 condition, &condition_session_name);
797 if (condition_status != LTTNG_CONDITION_STATUS_OK) {
798 ERR("[rotation-thread] Session name could not be fetched");
799 ret = -1;
800 goto end;
801 }
802 evaluation_status = lttng_evaluation_session_consumed_size_get_consumed_size(evaluation,
803 &consumed);
804 if (evaluation_status != LTTNG_EVALUATION_STATUS_OK) {
805 ERR("[rotation-thread] Failed to get evaluation");
806 ret = -1;
807 goto end;
808 }
809
810 session_lock_list();
811 session = session_find_by_name(condition_session_name);
812 if (!session) {
813 ret = -1;
814 session_unlock_list();
815 ERR("[rotation-thread] Session \"%s\" not found",
816 condition_session_name);
817 goto end;
818 }
819 session_lock(session);
820 session_unlock_list();
821
822 ret = unsubscribe_session_consumed_size_rotation(session,
823 notification_thread_handle);
824 if (ret) {
825 goto end_unlock;
826 }
827
828 ret = cmd_rotate_session(session, NULL);
829 if (ret == -LTTNG_ERR_ROTATION_PENDING) {
830 DBG("Rotate already pending, subscribe to the next threshold value");
831 } else if (ret != LTTNG_OK) {
832 ERR("[rotation-thread] Failed to rotate on size notification with error: %s",
833 lttng_strerror(ret));
834 ret = -1;
835 goto end_unlock;
836 }
837 ret = subscribe_session_consumed_size_rotation(session,
838 consumed + session->rotate_size,
839 notification_thread_handle);
840 if (ret) {
841 ERR("[rotation-thread] Failed to subscribe to session consumed size condition");
842 goto end_unlock;
843 }
844 ret = 0;
845
846 end_unlock:
847 session_unlock(session);
848 session_put(session);
849 end:
850 return ret;
851 }
852
853 static
854 int handle_notification_channel(int fd,
855 struct rotation_thread_handle *handle,
856 struct rotation_thread *state)
857 {
858 int ret;
859 bool notification_pending;
860 struct lttng_notification *notification = NULL;
861 enum lttng_notification_channel_status status;
862 const struct lttng_evaluation *notification_evaluation;
863 const struct lttng_condition *notification_condition;
864
865 status = lttng_notification_channel_has_pending_notification(
866 rotate_notification_channel, &notification_pending);
867 if (status != LTTNG_NOTIFICATION_CHANNEL_STATUS_OK) {
868 ERR("[rotation-thread ]Error occurred while checking for pending notification");
869 ret = -1;
870 goto end;
871 }
872
873 if (!notification_pending) {
874 ret = 0;
875 goto end;
876 }
877
878 /* Receive the next notification. */
879 status = lttng_notification_channel_get_next_notification(
880 rotate_notification_channel,
881 &notification);
882
883 switch (status) {
884 case LTTNG_NOTIFICATION_CHANNEL_STATUS_OK:
885 break;
886 case LTTNG_NOTIFICATION_CHANNEL_STATUS_NOTIFICATIONS_DROPPED:
887 /* Not an error, we will wait for the next one */
888 ret = 0;
889 goto end;;
890 case LTTNG_NOTIFICATION_CHANNEL_STATUS_CLOSED:
891 ERR("Notification channel was closed");
892 ret = -1;
893 goto end;
894 default:
895 /* Unhandled conditions / errors. */
896 ERR("Unknown notification channel status");
897 ret = -1;
898 goto end;
899 }
900
901 notification_condition = lttng_notification_get_condition(notification);
902 notification_evaluation = lttng_notification_get_evaluation(notification);
903
904 ret = handle_condition(notification_condition, notification_evaluation,
905 handle->notification_thread_handle);
906
907 end:
908 lttng_notification_destroy(notification);
909 return ret;
910 }
911
912 void *thread_rotation(void *data)
913 {
914 int ret;
915 struct rotation_thread_handle *handle = data;
916 struct rotation_thread thread;
917
918 DBG("[rotation-thread] Started rotation thread");
919
920 if (!handle) {
921 ERR("[rotation-thread] Invalid thread context provided");
922 goto end;
923 }
924
925 rcu_register_thread();
926 rcu_thread_online();
927
928 health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ROTATION);
929 health_code_update();
930
931 ret = init_thread_state(handle, &thread);
932 if (ret) {
933 goto error;
934 }
935
936 /* Ready to handle client connections. */
937 sessiond_notify_ready();
938
939 while (true) {
940 int fd_count, i;
941
942 health_poll_entry();
943 DBG("[rotation-thread] Entering poll wait");
944 ret = lttng_poll_wait(&thread.events, -1);
945 DBG("[rotation-thread] Poll wait returned (%i)", ret);
946 health_poll_exit();
947 if (ret < 0) {
948 /*
949 * Restart interrupted system call.
950 */
951 if (errno == EINTR) {
952 continue;
953 }
954 ERR("[rotation-thread] Error encountered during lttng_poll_wait (%i)", ret);
955 goto error;
956 }
957
958 fd_count = ret;
959 for (i = 0; i < fd_count; i++) {
960 int fd = LTTNG_POLL_GETFD(&thread.events, i);
961 uint32_t revents = LTTNG_POLL_GETEV(&thread.events, i);
962
963 DBG("[rotation-thread] Handling fd (%i) activity (%u)",
964 fd, revents);
965
966 if (revents & LPOLLERR) {
967 ERR("[rotation-thread] Polling returned an error on fd %i", fd);
968 goto error;
969 }
970
971 if (fd == rotate_notification_channel->socket) {
972 ret = handle_notification_channel(fd, handle,
973 &thread);
974 if (ret) {
975 ERR("[rotation-thread] Error occurred while handling activity on notification channel socket");
976 goto error;
977 }
978 } else {
979 /* Job queue or quit pipe activity. */
980 if (fd == lttng_pipe_get_readfd(
981 handle->rotation_timer_queue->event_pipe)) {
982 char buf;
983
984 ret = lttng_read(fd, &buf, 1);
985 if (ret != 1) {
986 ERR("[rotation-thread] Failed to read from wakeup pipe (fd = %i)", fd);
987 ret = -1;
988 goto error;
989 }
990 }
991
992 /*
993 * The job queue is serviced if there is
994 * activity on the quit pipe to ensure it is
995 * flushed and all references held in the queue
996 * are released.
997 */
998 ret = handle_job_queue(handle, &thread,
999 handle->rotation_timer_queue);
1000 if (ret) {
1001 ERR("[rotation-thread] Failed to handle rotation timer pipe event");
1002 goto error;
1003 }
1004
1005 if (sessiond_check_thread_quit_pipe(fd, revents)) {
1006 DBG("[rotation-thread] Quit pipe activity");
1007 goto exit;
1008 }
1009 }
1010 }
1011 }
1012 exit:
1013 error:
1014 DBG("[rotation-thread] Exit");
1015 fini_thread_state(&thread);
1016 health_unregister(health_sessiond);
1017 rcu_thread_offline();
1018 rcu_unregister_thread();
1019 end:
1020 return NULL;
1021 }
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