Fix: streaming and snapshot backward compat for relayd < 2.11
[lttng-tools.git] / src / bin / lttng-sessiond / session.c
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2 only,
6 * as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 */
17
18 #define _LGPL_SOURCE
19 #include <limits.h>
20 #include <inttypes.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <sys/stat.h>
25 #include <urcu.h>
26 #include <dirent.h>
27 #include <sys/types.h>
28 #include <pthread.h>
29
30 #include <common/common.h>
31 #include <common/utils.h>
32 #include <common/trace-chunk.h>
33 #include <common/sessiond-comm/sessiond-comm.h>
34 #include <lttng/location-internal.h>
35 #include "lttng-sessiond.h"
36 #include "kernel.h"
37
38 #include "session.h"
39 #include "utils.h"
40 #include "trace-ust.h"
41 #include "timer.h"
42 #include "cmd.h"
43
44 struct ltt_session_destroy_notifier_element {
45 ltt_session_destroy_notifier notifier;
46 void *user_data;
47 };
48
49 /*
50 * NOTES:
51 *
52 * No ltt_session.lock is taken here because those data structure are widely
53 * spread across the lttng-tools code base so before caling functions below
54 * that can read/write a session, the caller MUST acquire the session lock
55 * using session_lock() and session_unlock().
56 */
57
58 /*
59 * Init tracing session list.
60 *
61 * Please see session.h for more explanation and correct usage of the list.
62 */
63 static struct ltt_session_list ltt_session_list = {
64 .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
65 .lock = PTHREAD_MUTEX_INITIALIZER,
66 .removal_cond = PTHREAD_COND_INITIALIZER,
67 .next_uuid = 0,
68 };
69
70 /* These characters are forbidden in a session name. Used by validate_name. */
71 static const char *forbidden_name_chars = "/";
72
73 /* Global hash table to keep the sessions, indexed by id. */
74 static struct lttng_ht *ltt_sessions_ht_by_id = NULL;
75
76 /*
77 * Validate the session name for forbidden characters.
78 *
79 * Return 0 on success else -1 meaning a forbidden char. has been found.
80 */
81 static int validate_name(const char *name)
82 {
83 int ret;
84 char *tok, *tmp_name;
85
86 assert(name);
87
88 tmp_name = strdup(name);
89 if (!tmp_name) {
90 /* ENOMEM here. */
91 ret = -1;
92 goto error;
93 }
94
95 tok = strpbrk(tmp_name, forbidden_name_chars);
96 if (tok) {
97 DBG("Session name %s contains a forbidden character", name);
98 /* Forbidden character has been found. */
99 ret = -1;
100 goto error;
101 }
102 ret = 0;
103
104 error:
105 free(tmp_name);
106 return ret;
107 }
108
109 /*
110 * Add a ltt_session structure to the global list.
111 *
112 * The caller MUST acquire the session list lock before.
113 * Returns the unique identifier for the session.
114 */
115 static uint64_t add_session_list(struct ltt_session *ls)
116 {
117 assert(ls);
118
119 cds_list_add(&ls->list, &ltt_session_list.head);
120 return ltt_session_list.next_uuid++;
121 }
122
123 /*
124 * Delete a ltt_session structure to the global list.
125 *
126 * The caller MUST acquire the session list lock before.
127 */
128 static void del_session_list(struct ltt_session *ls)
129 {
130 assert(ls);
131
132 cds_list_del(&ls->list);
133 }
134
135 /*
136 * Return a pointer to the session list.
137 */
138 struct ltt_session_list *session_get_list(void)
139 {
140 return &ltt_session_list;
141 }
142
143 /*
144 * Returns once the session list is empty.
145 */
146 void session_list_wait_empty(void)
147 {
148 pthread_mutex_lock(&ltt_session_list.lock);
149 while (!cds_list_empty(&ltt_session_list.head)) {
150 pthread_cond_wait(&ltt_session_list.removal_cond,
151 &ltt_session_list.lock);
152 }
153 pthread_mutex_unlock(&ltt_session_list.lock);
154 }
155
156 /*
157 * Acquire session list lock
158 */
159 void session_lock_list(void)
160 {
161 pthread_mutex_lock(&ltt_session_list.lock);
162 }
163
164 /*
165 * Try to acquire session list lock
166 */
167 int session_trylock_list(void)
168 {
169 return pthread_mutex_trylock(&ltt_session_list.lock);
170 }
171
172 /*
173 * Release session list lock
174 */
175 void session_unlock_list(void)
176 {
177 pthread_mutex_unlock(&ltt_session_list.lock);
178 }
179
180 /*
181 * Get the session's consumer destination type.
182 *
183 * The caller must hold the session lock.
184 */
185 enum consumer_dst_type session_get_consumer_destination_type(
186 const struct ltt_session *session)
187 {
188 /*
189 * The output information is duplicated in both of those session types.
190 * Hence, it doesn't matter from which it is retrieved. However, it is
191 * possible for only one of them to be set.
192 */
193 return session->kernel_session ?
194 session->kernel_session->consumer->type :
195 session->ust_session->consumer->type;
196 }
197
198 /*
199 * Get the session's consumer network hostname.
200 * The caller must ensure that the destination is of type "net".
201 *
202 * The caller must hold the session lock.
203 */
204 const char *session_get_net_consumer_hostname(const struct ltt_session *session)
205 {
206 const char *hostname = NULL;
207 const struct consumer_output *output;
208
209 output = session->kernel_session ?
210 session->kernel_session->consumer :
211 session->ust_session->consumer;
212
213 /*
214 * hostname is assumed to be the same for both control and data
215 * connections.
216 */
217 switch (output->dst.net.control.dtype) {
218 case LTTNG_DST_IPV4:
219 hostname = output->dst.net.control.dst.ipv4;
220 break;
221 case LTTNG_DST_IPV6:
222 hostname = output->dst.net.control.dst.ipv6;
223 break;
224 default:
225 abort();
226 }
227 return hostname;
228 }
229
230 /*
231 * Get the session's consumer network control and data ports.
232 * The caller must ensure that the destination is of type "net".
233 *
234 * The caller must hold the session lock.
235 */
236 void session_get_net_consumer_ports(const struct ltt_session *session,
237 uint16_t *control_port, uint16_t *data_port)
238 {
239 const struct consumer_output *output;
240
241 output = session->kernel_session ?
242 session->kernel_session->consumer :
243 session->ust_session->consumer;
244 *control_port = output->dst.net.control.port;
245 *data_port = output->dst.net.data.port;
246 }
247
248 /*
249 * Get the location of the latest trace archive produced by a rotation.
250 *
251 * The caller must hold the session lock.
252 */
253 struct lttng_trace_archive_location *session_get_trace_archive_location(
254 const struct ltt_session *session)
255 {
256 int ret;
257 struct lttng_trace_archive_location *location = NULL;
258 char *chunk_path = NULL;
259
260 if (session->rotation_state != LTTNG_ROTATION_STATE_COMPLETED ||
261 !session->last_archived_chunk_name) {
262 goto end;
263 }
264
265 ret = asprintf(&chunk_path, "%s/" DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY "/%s",
266 session_get_base_path(session),
267 session->last_archived_chunk_name);
268 if (ret == -1) {
269 goto end;
270 }
271
272 switch (session_get_consumer_destination_type(session)) {
273 case CONSUMER_DST_LOCAL:
274 location = lttng_trace_archive_location_local_create(
275 chunk_path);
276 break;
277 case CONSUMER_DST_NET:
278 {
279 const char *hostname;
280 uint16_t control_port, data_port;
281
282 hostname = session_get_net_consumer_hostname(session);
283 session_get_net_consumer_ports(session,
284 &control_port,
285 &data_port);
286 location = lttng_trace_archive_location_relay_create(
287 hostname,
288 LTTNG_TRACE_ARCHIVE_LOCATION_RELAY_PROTOCOL_TYPE_TCP,
289 control_port, data_port, chunk_path);
290 break;
291 }
292 default:
293 abort();
294 }
295 end:
296 free(chunk_path);
297 return location;
298 }
299
300 /*
301 * Allocate the ltt_sessions_ht_by_id HT.
302 *
303 * The session list lock must be held.
304 */
305 int ltt_sessions_ht_alloc(void)
306 {
307 int ret = 0;
308
309 DBG("Allocating ltt_sessions_ht_by_id");
310 ltt_sessions_ht_by_id = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
311 if (!ltt_sessions_ht_by_id) {
312 ret = -1;
313 ERR("Failed to allocate ltt_sessions_ht_by_id");
314 goto end;
315 }
316 end:
317 return ret;
318 }
319
320 /*
321 * Destroy the ltt_sessions_ht_by_id HT.
322 *
323 * The session list lock must be held.
324 */
325 static void ltt_sessions_ht_destroy(void)
326 {
327 if (!ltt_sessions_ht_by_id) {
328 return;
329 }
330 ht_cleanup_push(ltt_sessions_ht_by_id);
331 ltt_sessions_ht_by_id = NULL;
332 }
333
334 /*
335 * Add a ltt_session to the ltt_sessions_ht_by_id.
336 * If unallocated, the ltt_sessions_ht_by_id HT is allocated.
337 * The session list lock must be held.
338 */
339 static void add_session_ht(struct ltt_session *ls)
340 {
341 int ret;
342
343 assert(ls);
344
345 if (!ltt_sessions_ht_by_id) {
346 ret = ltt_sessions_ht_alloc();
347 if (ret) {
348 ERR("Error allocating the sessions HT");
349 goto end;
350 }
351 }
352 lttng_ht_node_init_u64(&ls->node, ls->id);
353 lttng_ht_add_unique_u64(ltt_sessions_ht_by_id, &ls->node);
354
355 end:
356 return;
357 }
358
359 /*
360 * Test if ltt_sessions_ht_by_id is empty.
361 * Return 1 if empty, 0 if not empty.
362 * The session list lock must be held.
363 */
364 static int ltt_sessions_ht_empty(void)
365 {
366 int ret;
367
368 if (!ltt_sessions_ht_by_id) {
369 ret = 1;
370 goto end;
371 }
372
373 ret = lttng_ht_get_count(ltt_sessions_ht_by_id) ? 0 : 1;
374 end:
375 return ret;
376 }
377
378 /*
379 * Remove a ltt_session from the ltt_sessions_ht_by_id.
380 * If empty, the ltt_sessions_ht_by_id HT is freed.
381 * The session list lock must be held.
382 */
383 static void del_session_ht(struct ltt_session *ls)
384 {
385 struct lttng_ht_iter iter;
386 int ret;
387
388 assert(ls);
389 assert(ltt_sessions_ht_by_id);
390
391 iter.iter.node = &ls->node.node;
392 ret = lttng_ht_del(ltt_sessions_ht_by_id, &iter);
393 assert(!ret);
394
395 if (ltt_sessions_ht_empty()) {
396 DBG("Empty ltt_sessions_ht_by_id, destroying it");
397 ltt_sessions_ht_destroy();
398 }
399 }
400
401 /*
402 * Acquire session lock
403 */
404 void session_lock(struct ltt_session *session)
405 {
406 assert(session);
407
408 pthread_mutex_lock(&session->lock);
409 }
410
411 /*
412 * Release session lock
413 */
414 void session_unlock(struct ltt_session *session)
415 {
416 assert(session);
417
418 pthread_mutex_unlock(&session->lock);
419 }
420
421 static
422 int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
423 struct lttng_trace_chunk *new_trace_chunk,
424 struct lttng_trace_chunk **_current_trace_chunk)
425 {
426 int ret;
427 unsigned int i, refs_to_acquire = 0, refs_acquired = 0, refs_to_release = 0;
428 struct cds_lfht_iter iter;
429 struct consumer_socket *socket;
430 struct lttng_trace_chunk *current_trace_chunk;
431 uint64_t chunk_id;
432 enum lttng_trace_chunk_status chunk_status;
433
434 rcu_read_lock();
435 /*
436 * Ownership of current trace chunk is transferred to
437 * `current_trace_chunk`.
438 */
439 current_trace_chunk = session->current_trace_chunk;
440 session->current_trace_chunk = NULL;
441 if (session->ust_session) {
442 lttng_trace_chunk_put(
443 session->ust_session->current_trace_chunk);
444 session->ust_session->current_trace_chunk = NULL;
445 }
446 if (session->kernel_session) {
447 lttng_trace_chunk_put(
448 session->kernel_session->current_trace_chunk);
449 session->kernel_session->current_trace_chunk = NULL;
450 }
451 if (!new_trace_chunk) {
452 ret = 0;
453 goto end;
454 }
455 chunk_status = lttng_trace_chunk_get_id(new_trace_chunk, &chunk_id);
456 assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
457
458 refs_to_acquire = 1;
459 refs_to_acquire += !!session->ust_session;
460 refs_to_acquire += !!session->kernel_session;
461
462 for (refs_acquired = 0; refs_acquired < refs_to_acquire;
463 refs_acquired++) {
464 if (!lttng_trace_chunk_get(new_trace_chunk)) {
465 ERR("Failed to acquire reference to new trace chunk of session \"%s\"",
466 session->name);
467 goto error;
468 }
469 }
470
471 if (session->ust_session) {
472 const uint64_t relayd_id =
473 session->ust_session->consumer->net_seq_index;
474 const bool is_local_trace =
475 session->ust_session->consumer->type ==
476 CONSUMER_DST_LOCAL;
477
478 session->ust_session->current_trace_chunk = new_trace_chunk;
479 if (is_local_trace) {
480 enum lttng_error_code ret_error_code;
481
482 ret_error_code = ust_app_create_channel_subdirectories(
483 session->ust_session);
484 if (ret_error_code != LTTNG_OK) {
485 ret = -ret_error_code;
486 goto error;
487 }
488 }
489 cds_lfht_for_each_entry(
490 session->ust_session->consumer->socks->ht,
491 &iter, socket, node.node) {
492 pthread_mutex_lock(socket->lock);
493 ret = consumer_create_trace_chunk(socket,
494 relayd_id,
495 session->id, new_trace_chunk);
496 pthread_mutex_unlock(socket->lock);
497 if (ret) {
498 goto error;
499 }
500 }
501 }
502 if (session->kernel_session) {
503 const uint64_t relayd_id =
504 session->kernel_session->consumer->net_seq_index;
505 const bool is_local_trace =
506 session->kernel_session->consumer->type ==
507 CONSUMER_DST_LOCAL;
508
509 session->kernel_session->current_trace_chunk = new_trace_chunk;
510 if (is_local_trace) {
511 enum lttng_error_code ret_error_code;
512
513 ret_error_code = kernel_create_channel_subdirectories(
514 session->kernel_session);
515 if (ret_error_code != LTTNG_OK) {
516 ret = -ret_error_code;
517 goto error;
518 }
519 }
520 cds_lfht_for_each_entry(
521 session->kernel_session->consumer->socks->ht,
522 &iter, socket, node.node) {
523 pthread_mutex_lock(socket->lock);
524 ret = consumer_create_trace_chunk(socket,
525 relayd_id,
526 session->id, new_trace_chunk);
527 pthread_mutex_unlock(socket->lock);
528 if (ret) {
529 goto error;
530 }
531 }
532 }
533
534 /*
535 * Update local current trace chunk state last, only if all remote
536 * creations succeeded.
537 */
538 session->current_trace_chunk = new_trace_chunk;
539 LTTNG_OPTIONAL_SET(&session->most_recent_chunk_id, chunk_id);
540 end:
541 if (_current_trace_chunk) {
542 *_current_trace_chunk = current_trace_chunk;
543 current_trace_chunk = NULL;
544 }
545 end_no_move:
546 rcu_read_unlock();
547 lttng_trace_chunk_put(current_trace_chunk);
548 return ret;
549 error:
550 if (session->ust_session) {
551 session->ust_session->current_trace_chunk = NULL;
552 }
553 if (session->kernel_session) {
554 session->kernel_session->current_trace_chunk = NULL;
555 }
556 /*
557 * Release references taken in the case where all references could not
558 * be acquired.
559 */
560 refs_to_release = refs_to_acquire - refs_acquired;
561 for (i = 0; i < refs_to_release; i++) {
562 lttng_trace_chunk_put(new_trace_chunk);
563 }
564 ret = -1;
565 goto end_no_move;
566 }
567
568 struct lttng_trace_chunk *session_create_new_trace_chunk(
569 const struct ltt_session *session,
570 const struct consumer_output *consumer_output_override,
571 const char *session_base_path_override,
572 const char *chunk_name_override)
573 {
574 int ret;
575 struct lttng_trace_chunk *trace_chunk = NULL;
576 enum lttng_trace_chunk_status chunk_status;
577 const time_t chunk_creation_ts = time(NULL);
578 bool is_local_trace;
579 const char *base_path;
580 struct lttng_directory_handle session_output_directory;
581 const struct lttng_credentials session_credentials = {
582 .uid = session->uid,
583 .gid = session->gid,
584 };
585 uint64_t next_chunk_id;
586 const struct consumer_output *output;
587
588 if (consumer_output_override) {
589 output = consumer_output_override;
590 } else {
591 assert(session->ust_session || session->kernel_session);
592 output = session->ust_session ?
593 session->ust_session->consumer :
594 session->kernel_session->consumer;
595 }
596
597 is_local_trace = output->type == CONSUMER_DST_LOCAL;
598 base_path = session_base_path_override ? :
599 consumer_output_get_base_path(output);
600
601 if (chunk_creation_ts == (time_t) -1) {
602 PERROR("Failed to sample time while creation session \"%s\" trace chunk",
603 session->name);
604 goto error;
605 }
606
607 next_chunk_id = session->most_recent_chunk_id.is_set ?
608 session->most_recent_chunk_id.value + 1 : 0;
609
610 trace_chunk = lttng_trace_chunk_create(next_chunk_id,
611 chunk_creation_ts);
612 if (!trace_chunk) {
613 goto error;
614 }
615
616 if (chunk_name_override) {
617 chunk_status = lttng_trace_chunk_override_name(trace_chunk,
618 chunk_name_override);
619 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
620 goto error;
621 }
622 }
623
624 if (!is_local_trace) {
625 /*
626 * No need to set crendentials and output directory
627 * for remote trace chunks.
628 */
629 goto end;
630 }
631
632 chunk_status = lttng_trace_chunk_set_credentials(trace_chunk,
633 &session_credentials);
634 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
635 goto error;
636 }
637
638 DBG("Creating base output directory of session \"%s\" at %s",
639 session->name, base_path);
640 ret = utils_mkdir_recursive(base_path, S_IRWXU | S_IRWXG,
641 session->uid, session->gid);
642 if (ret) {
643 goto error;
644 }
645 ret = lttng_directory_handle_init(&session_output_directory,
646 base_path);
647 if (ret) {
648 goto error;
649 }
650 chunk_status = lttng_trace_chunk_set_as_owner(trace_chunk,
651 &session_output_directory);
652 lttng_directory_handle_fini(&session_output_directory);
653 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
654 goto error;
655 }
656 end:
657 return trace_chunk;
658 error:
659 lttng_trace_chunk_put(trace_chunk);
660 trace_chunk = NULL;
661 goto end;
662 }
663
664 int session_close_trace_chunk(const struct ltt_session *session,
665 struct lttng_trace_chunk *trace_chunk,
666 const enum lttng_trace_chunk_command_type *close_command)
667 {
668 int ret = 0;
669 bool error_occurred = false;
670 struct cds_lfht_iter iter;
671 struct consumer_socket *socket;
672 enum lttng_trace_chunk_status chunk_status;
673 const time_t chunk_close_timestamp = time(NULL);
674
675 if (close_command) {
676 chunk_status = lttng_trace_chunk_set_close_command(
677 trace_chunk, *close_command);
678 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
679 ret = -1;
680 goto end;
681 }
682 }
683
684 if (chunk_close_timestamp == (time_t) -1) {
685 ERR("Failed to sample the close timestamp of the current trace chunk of session \"%s\"",
686 session->name);
687 ret = -1;
688 goto end;
689 }
690 chunk_status = lttng_trace_chunk_set_close_timestamp(trace_chunk,
691 chunk_close_timestamp);
692 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
693 ERR("Failed to set the close timestamp of the current trace chunk of session \"%s\"",
694 session->name);
695 ret = -1;
696 goto end;
697 }
698
699 if (session->ust_session) {
700 const uint64_t relayd_id =
701 session->ust_session->consumer->net_seq_index;
702
703 cds_lfht_for_each_entry(
704 session->ust_session->consumer->socks->ht,
705 &iter, socket, node.node) {
706 pthread_mutex_lock(socket->lock);
707 ret = consumer_close_trace_chunk(socket,
708 relayd_id,
709 session->id,
710 trace_chunk);
711 pthread_mutex_unlock(socket->lock);
712 if (ret) {
713 ERR("Failed to close trace chunk on user space consumer");
714 error_occurred = true;
715 }
716 }
717 }
718 if (session->kernel_session) {
719 const uint64_t relayd_id =
720 session->kernel_session->consumer->net_seq_index;
721
722 cds_lfht_for_each_entry(
723 session->kernel_session->consumer->socks->ht,
724 &iter, socket, node.node) {
725 pthread_mutex_lock(socket->lock);
726 ret = consumer_close_trace_chunk(socket,
727 relayd_id,
728 session->id,
729 trace_chunk);
730 pthread_mutex_unlock(socket->lock);
731 if (ret) {
732 ERR("Failed to close trace chunk on kernel consumer");
733 error_occurred = true;
734 }
735 }
736 }
737 ret = error_occurred ? -1 : 0;
738 end:
739 return ret;
740 }
741
742 /*
743 * Set a session's current trace chunk.
744 *
745 * Must be called with the session lock held.
746 */
747 int session_set_trace_chunk(struct ltt_session *session,
748 struct lttng_trace_chunk *new_trace_chunk,
749 struct lttng_trace_chunk **current_trace_chunk)
750 {
751 ASSERT_LOCKED(session->lock);
752 return _session_set_trace_chunk_no_lock_check(session, new_trace_chunk,
753 current_trace_chunk);
754 }
755
756 static
757 void session_notify_destruction(const struct ltt_session *session)
758 {
759 size_t i;
760 const size_t count = lttng_dynamic_array_get_count(
761 &session->destroy_notifiers);
762
763 for (i = 0; i < count; i++) {
764 const struct ltt_session_destroy_notifier_element *element =
765 lttng_dynamic_array_get_element(
766 &session->destroy_notifiers, i);
767
768 element->notifier(session, element->user_data);
769 }
770 }
771
772 static
773 void session_release(struct urcu_ref *ref)
774 {
775 int ret;
776 struct ltt_ust_session *usess;
777 struct ltt_kernel_session *ksess;
778 struct ltt_session *session = container_of(ref, typeof(*session), ref);
779 const bool session_published = session->published;
780
781 assert(!session->chunk_being_archived);
782
783 usess = session->ust_session;
784 ksess = session->kernel_session;
785
786 /* Clean kernel session teardown, keeping data for destroy notifier. */
787 kernel_destroy_session(ksess);
788
789 /* UST session teardown, keeping data for destroy notifier. */
790 if (usess) {
791 /* Close any relayd session */
792 consumer_output_send_destroy_relayd(usess->consumer);
793
794 /* Destroy every UST application related to this session. */
795 ret = ust_app_destroy_trace_all(usess);
796 if (ret) {
797 ERR("Error in ust_app_destroy_trace_all");
798 }
799
800 /* Clean up the rest, keeping destroy notifier data. */
801 trace_ust_destroy_session(usess);
802 }
803
804 /*
805 * Must notify the kernel thread here to update it's poll set in order to
806 * remove the channel(s)' fd just destroyed.
807 */
808 ret = notify_thread_pipe(kernel_poll_pipe[1]);
809 if (ret < 0) {
810 PERROR("write kernel poll pipe");
811 }
812
813 DBG("Destroying session %s (id %" PRIu64 ")", session->name, session->id);
814
815 consumer_output_put(session->consumer);
816 snapshot_destroy(&session->snapshot);
817
818 pthread_mutex_destroy(&session->lock);
819
820 if (session_published) {
821 ASSERT_LOCKED(ltt_session_list.lock);
822 del_session_list(session);
823 del_session_ht(session);
824 }
825 session_notify_destruction(session);
826
827 kernel_free_session(ksess);
828 session->kernel_session = NULL;
829 if (usess) {
830 trace_ust_free_session(usess);
831 session->ust_session = NULL;
832 }
833 lttng_dynamic_array_reset(&session->destroy_notifiers);
834 free(session->last_archived_chunk_name);
835 free(session->base_path);
836 free(session);
837 if (session_published) {
838 /*
839 * Broadcast after free-ing to ensure the memory is
840 * reclaimed before the main thread exits.
841 */
842 pthread_cond_broadcast(&ltt_session_list.removal_cond);
843 }
844 }
845
846 /*
847 * Acquire a reference to a session.
848 * This function may fail (return false); its return value must be checked.
849 */
850 bool session_get(struct ltt_session *session)
851 {
852 return urcu_ref_get_unless_zero(&session->ref);
853 }
854
855 /*
856 * Release a reference to a session.
857 */
858 void session_put(struct ltt_session *session)
859 {
860 if (!session) {
861 return;
862 }
863 /*
864 * The session list lock must be held as any session_put()
865 * may cause the removal of the session from the session_list.
866 */
867 ASSERT_LOCKED(ltt_session_list.lock);
868 assert(session->ref.refcount);
869 urcu_ref_put(&session->ref, session_release);
870 }
871
872 /*
873 * Destroy a session.
874 *
875 * This method does not immediately release/free the session as other
876 * components may still hold a reference to the session. However,
877 * the session should no longer be presented to the user.
878 *
879 * Releases the session list's reference to the session
880 * and marks it as destroyed. Iterations on the session list should be
881 * mindful of the "destroyed" flag.
882 */
883 void session_destroy(struct ltt_session *session)
884 {
885 assert(!session->destroyed);
886 session->destroyed = true;
887 session_put(session);
888 }
889
890 int session_add_destroy_notifier(struct ltt_session *session,
891 ltt_session_destroy_notifier notifier, void *user_data)
892 {
893 const struct ltt_session_destroy_notifier_element element = {
894 .notifier = notifier,
895 .user_data = user_data
896 };
897
898 return lttng_dynamic_array_add_element(&session->destroy_notifiers,
899 &element);
900 }
901
902 /*
903 * Return a ltt_session structure ptr that matches name. If no session found,
904 * NULL is returned. This must be called with the session list lock held using
905 * session_lock_list and session_unlock_list.
906 * A reference to the session is implicitly acquired by this function.
907 */
908 struct ltt_session *session_find_by_name(const char *name)
909 {
910 struct ltt_session *iter;
911
912 assert(name);
913 ASSERT_LOCKED(ltt_session_list.lock);
914
915 DBG2("Trying to find session by name %s", name);
916
917 cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
918 if (!strncmp(iter->name, name, NAME_MAX) &&
919 !iter->destroyed) {
920 goto found;
921 }
922 }
923
924 return NULL;
925 found:
926 return session_get(iter) ? iter : NULL;
927 }
928
929 /*
930 * Return an ltt_session that matches the id. If no session is found,
931 * NULL is returned. This must be called with rcu_read_lock and
932 * session list lock held (to guarantee the lifetime of the session).
933 */
934 struct ltt_session *session_find_by_id(uint64_t id)
935 {
936 struct lttng_ht_node_u64 *node;
937 struct lttng_ht_iter iter;
938 struct ltt_session *ls;
939
940 ASSERT_LOCKED(ltt_session_list.lock);
941
942 if (!ltt_sessions_ht_by_id) {
943 goto end;
944 }
945
946 lttng_ht_lookup(ltt_sessions_ht_by_id, &id, &iter);
947 node = lttng_ht_iter_get_node_u64(&iter);
948 if (node == NULL) {
949 goto end;
950 }
951 ls = caa_container_of(node, struct ltt_session, node);
952
953 DBG3("Session %" PRIu64 " found by id.", id);
954 return session_get(ls) ? ls : NULL;
955
956 end:
957 DBG3("Session %" PRIu64 " NOT found by id", id);
958 return NULL;
959 }
960
961 /*
962 * Create a new session and add it to the session list.
963 * Session list lock must be held by the caller.
964 */
965 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
966 const char *base_path, struct ltt_session **out_session)
967 {
968 int ret;
969 enum lttng_error_code ret_code;
970 struct ltt_session *new_session = NULL;
971
972 ASSERT_LOCKED(ltt_session_list.lock);
973 if (name) {
974 struct ltt_session *clashing_session;
975
976 clashing_session = session_find_by_name(name);
977 if (clashing_session) {
978 session_put(clashing_session);
979 ret_code = LTTNG_ERR_EXIST_SESS;
980 goto error;
981 }
982 }
983 new_session = zmalloc(sizeof(struct ltt_session));
984 if (!new_session) {
985 PERROR("Failed to allocate an ltt_session structure");
986 ret_code = LTTNG_ERR_NOMEM;
987 goto error;
988 }
989
990 lttng_dynamic_array_init(&new_session->destroy_notifiers,
991 sizeof(struct ltt_session_destroy_notifier_element),
992 NULL);
993 urcu_ref_init(&new_session->ref);
994 pthread_mutex_init(&new_session->lock, NULL);
995
996 new_session->creation_time = time(NULL);
997 if (new_session->creation_time == (time_t) -1) {
998 PERROR("Failed to sample session creation time");
999 ret_code = LTTNG_ERR_SESSION_FAIL;
1000 goto error;
1001 }
1002
1003 /* Create default consumer output. */
1004 new_session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
1005 if (new_session->consumer == NULL) {
1006 ret_code = LTTNG_ERR_NOMEM;
1007 goto error;
1008 }
1009
1010 if (name) {
1011 ret = lttng_strncpy(new_session->name, name, sizeof(new_session->name));
1012 if (ret) {
1013 ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
1014 goto error;
1015 }
1016 ret = validate_name(name);
1017 if (ret < 0) {
1018 ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
1019 goto error;
1020 }
1021 } else {
1022 int i = 0;
1023 bool found_name = false;
1024 char datetime[16];
1025 struct tm *timeinfo;
1026
1027 timeinfo = localtime(&new_session->creation_time);
1028 if (!timeinfo) {
1029 ret_code = LTTNG_ERR_SESSION_FAIL;
1030 goto error;
1031 }
1032 strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
1033 for (i = 0; i < INT_MAX; i++) {
1034 struct ltt_session *clashing_session;
1035
1036 if (i == 0) {
1037 ret = snprintf(new_session->name,
1038 sizeof(new_session->name),
1039 "%s-%s",
1040 DEFAULT_SESSION_NAME,
1041 datetime);
1042 } else {
1043 ret = snprintf(new_session->name,
1044 sizeof(new_session->name),
1045 "%s%d-%s",
1046 DEFAULT_SESSION_NAME, i,
1047 datetime);
1048 }
1049 new_session->name_contains_creation_time = true;
1050 if (ret == -1 || ret >= sizeof(new_session->name)) {
1051 /*
1052 * Null-terminate in case the name is used
1053 * in logging statements.
1054 */
1055 new_session->name[sizeof(new_session->name) - 1] = '\0';
1056 ret_code = LTTNG_ERR_SESSION_FAIL;
1057 goto error;
1058 }
1059
1060 clashing_session =
1061 session_find_by_name(new_session->name);
1062 session_put(clashing_session);
1063 if (!clashing_session) {
1064 found_name = true;
1065 break;
1066 }
1067 }
1068 if (found_name) {
1069 DBG("Generated session name \"%s\"", new_session->name);
1070 new_session->has_auto_generated_name = true;
1071 } else {
1072 ERR("Failed to auto-generate a session name");
1073 ret_code = LTTNG_ERR_SESSION_FAIL;
1074 goto error;
1075 }
1076 }
1077
1078 ret = gethostname(new_session->hostname, sizeof(new_session->hostname));
1079 if (ret < 0) {
1080 if (errno == ENAMETOOLONG) {
1081 new_session->hostname[sizeof(new_session->hostname) - 1] = '\0';
1082 ERR("Hostname exceeds the maximal permitted length and has been truncated to %s",
1083 new_session->hostname);
1084 } else {
1085 ret_code = LTTNG_ERR_SESSION_FAIL;
1086 goto error;
1087 }
1088 }
1089
1090 if (base_path) {
1091 new_session->base_path = strdup(base_path);
1092 if (!new_session->base_path) {
1093 ERR("Failed to allocate base path of session \"%s\"",
1094 name);
1095 ret_code = LTTNG_ERR_SESSION_FAIL;
1096 goto error;
1097 }
1098 }
1099
1100 new_session->uid = uid;
1101 new_session->gid = gid;
1102
1103 ret = snapshot_init(&new_session->snapshot);
1104 if (ret < 0) {
1105 ret_code = LTTNG_ERR_NOMEM;
1106 goto error;
1107 }
1108
1109 new_session->rotation_state = LTTNG_ROTATION_STATE_NO_ROTATION;
1110
1111 /* Add new session to the session list. */
1112 new_session->id = add_session_list(new_session);
1113
1114 /*
1115 * Add the new session to the ltt_sessions_ht_by_id.
1116 * No ownership is taken by the hash table; it is merely
1117 * a wrapper around the session list used for faster access
1118 * by session id.
1119 */
1120 add_session_ht(new_session);
1121 new_session->published = true;
1122
1123 /*
1124 * Consumer is left to NULL since the create_session_uri command will
1125 * set it up and, if valid, assign it to the session.
1126 */
1127 DBG("Tracing session %s created with ID %" PRIu64 " by uid = %d, gid = %d",
1128 new_session->name, new_session->id, new_session->uid,
1129 new_session->gid);
1130 ret_code = LTTNG_OK;
1131 end:
1132 if (new_session) {
1133 (void) session_get(new_session);
1134 *out_session = new_session;
1135 }
1136 return ret_code;
1137 error:
1138 session_put(new_session);
1139 new_session = NULL;
1140 goto end;
1141 }
1142
1143 /*
1144 * Check if the UID or GID match the session. Root user has access to all
1145 * sessions.
1146 */
1147 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid)
1148 {
1149 assert(session);
1150
1151 if (uid != session->uid && gid != session->gid && uid != 0) {
1152 return 0;
1153 } else {
1154 return 1;
1155 }
1156 }
1157
1158 /*
1159 * Set a session's rotation state and reset all associated state.
1160 *
1161 * This function resets the rotation state (check timers, pending
1162 * flags, etc.) and sets the result of the last rotation. The result
1163 * can be queries by a liblttng-ctl client.
1164 *
1165 * Be careful of the result passed to this function. For instance,
1166 * on failure to launch a rotation, a client will expect the rotation
1167 * state to be set to "NO_ROTATION". If an error occured while the
1168 * rotation was "ONGOING", result should be set to "ERROR", which will
1169 * allow a client to report it.
1170 *
1171 * Must be called with the session and session_list locks held.
1172 */
1173 int session_reset_rotation_state(struct ltt_session *session,
1174 enum lttng_rotation_state result)
1175 {
1176 int ret = 0;
1177
1178 ASSERT_LOCKED(ltt_session_list.lock);
1179 ASSERT_LOCKED(session->lock);
1180
1181 session->rotation_state = result;
1182 if (session->rotation_pending_check_timer_enabled) {
1183 ret = timer_session_rotation_pending_check_stop(session);
1184 }
1185 if (session->chunk_being_archived) {
1186 uint64_t chunk_id;
1187 enum lttng_trace_chunk_status chunk_status;
1188
1189 chunk_status = lttng_trace_chunk_get_id(
1190 session->chunk_being_archived,
1191 &chunk_id);
1192 assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
1193 LTTNG_OPTIONAL_SET(&session->last_archived_chunk_id,
1194 chunk_id);
1195 lttng_trace_chunk_put(session->chunk_being_archived);
1196 session->chunk_being_archived = NULL;
1197 }
1198 return ret;
1199 }
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