602059424fd0d9fc8f54044111c5b2f02668e88c
[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 bool session_output_supports_trace_chunks(const struct ltt_session *session)
569 {
570 const struct consumer_output *output = session->kernel_session ?
571 session->kernel_session->consumer :
572 session->ust_session->consumer;
573
574 if (output->type == CONSUMER_DST_LOCAL) {
575 return true;
576 } else {
577 if (output->relay_major_version > 2) {
578 return true;
579 } else if (output->relay_major_version == 2 &&
580 output->relay_minor_version >= 11) {
581 return true;
582 }
583 }
584 return false;
585 }
586
587 struct lttng_trace_chunk *session_create_new_trace_chunk(
588 const struct ltt_session *session,
589 const struct consumer_output *consumer_output_override,
590 const char *session_base_path_override,
591 const char *chunk_name_override)
592 {
593 int ret;
594 struct lttng_trace_chunk *trace_chunk = NULL;
595 enum lttng_trace_chunk_status chunk_status;
596 const time_t chunk_creation_ts = time(NULL);
597 bool is_local_trace;
598 const char *base_path;
599 struct lttng_directory_handle session_output_directory;
600 const struct lttng_credentials session_credentials = {
601 .uid = session->uid,
602 .gid = session->gid,
603 };
604 uint64_t next_chunk_id;
605 const struct consumer_output *output;
606
607 if (consumer_output_override) {
608 output = consumer_output_override;
609 } else {
610 assert(session->ust_session || session->kernel_session);
611 output = session->ust_session ?
612 session->ust_session->consumer :
613 session->kernel_session->consumer;
614 }
615
616 is_local_trace = output->type == CONSUMER_DST_LOCAL;
617 base_path = session_base_path_override ? :
618 consumer_output_get_base_path(output);
619
620 if (chunk_creation_ts == (time_t) -1) {
621 PERROR("Failed to sample time while creation session \"%s\" trace chunk",
622 session->name);
623 goto error;
624 }
625
626 next_chunk_id = session->most_recent_chunk_id.is_set ?
627 session->most_recent_chunk_id.value + 1 : 0;
628
629 trace_chunk = lttng_trace_chunk_create(next_chunk_id,
630 chunk_creation_ts);
631 if (!trace_chunk) {
632 goto error;
633 }
634
635 if (chunk_name_override) {
636 chunk_status = lttng_trace_chunk_override_name(trace_chunk,
637 chunk_name_override);
638 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
639 goto error;
640 }
641 }
642
643 if (!is_local_trace) {
644 /*
645 * No need to set crendentials and output directory
646 * for remote trace chunks.
647 */
648 goto end;
649 }
650
651 chunk_status = lttng_trace_chunk_set_credentials(trace_chunk,
652 &session_credentials);
653 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
654 goto error;
655 }
656
657 DBG("Creating base output directory of session \"%s\" at %s",
658 session->name, base_path);
659 ret = utils_mkdir_recursive(base_path, S_IRWXU | S_IRWXG,
660 session->uid, session->gid);
661 if (ret) {
662 goto error;
663 }
664 ret = lttng_directory_handle_init(&session_output_directory,
665 base_path);
666 if (ret) {
667 goto error;
668 }
669 chunk_status = lttng_trace_chunk_set_as_owner(trace_chunk,
670 &session_output_directory);
671 lttng_directory_handle_fini(&session_output_directory);
672 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
673 goto error;
674 }
675 end:
676 return trace_chunk;
677 error:
678 lttng_trace_chunk_put(trace_chunk);
679 trace_chunk = NULL;
680 goto end;
681 }
682
683 int session_close_trace_chunk(const struct ltt_session *session,
684 struct lttng_trace_chunk *trace_chunk,
685 const enum lttng_trace_chunk_command_type *close_command)
686 {
687 int ret = 0;
688 bool error_occurred = false;
689 struct cds_lfht_iter iter;
690 struct consumer_socket *socket;
691 enum lttng_trace_chunk_status chunk_status;
692 const time_t chunk_close_timestamp = time(NULL);
693
694 if (close_command) {
695 chunk_status = lttng_trace_chunk_set_close_command(
696 trace_chunk, *close_command);
697 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
698 ret = -1;
699 goto end;
700 }
701 }
702
703 if (chunk_close_timestamp == (time_t) -1) {
704 ERR("Failed to sample the close timestamp of the current trace chunk of session \"%s\"",
705 session->name);
706 ret = -1;
707 goto end;
708 }
709 chunk_status = lttng_trace_chunk_set_close_timestamp(trace_chunk,
710 chunk_close_timestamp);
711 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
712 ERR("Failed to set the close timestamp of the current trace chunk of session \"%s\"",
713 session->name);
714 ret = -1;
715 goto end;
716 }
717
718 if (session->ust_session) {
719 const uint64_t relayd_id =
720 session->ust_session->consumer->net_seq_index;
721
722 cds_lfht_for_each_entry(
723 session->ust_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 user space consumer");
733 error_occurred = true;
734 }
735 }
736 }
737 if (session->kernel_session) {
738 const uint64_t relayd_id =
739 session->kernel_session->consumer->net_seq_index;
740
741 cds_lfht_for_each_entry(
742 session->kernel_session->consumer->socks->ht,
743 &iter, socket, node.node) {
744 pthread_mutex_lock(socket->lock);
745 ret = consumer_close_trace_chunk(socket,
746 relayd_id,
747 session->id,
748 trace_chunk);
749 pthread_mutex_unlock(socket->lock);
750 if (ret) {
751 ERR("Failed to close trace chunk on kernel consumer");
752 error_occurred = true;
753 }
754 }
755 }
756 ret = error_occurred ? -1 : 0;
757 end:
758 return ret;
759 }
760
761 /*
762 * Set a session's current trace chunk.
763 *
764 * Must be called with the session lock held.
765 */
766 int session_set_trace_chunk(struct ltt_session *session,
767 struct lttng_trace_chunk *new_trace_chunk,
768 struct lttng_trace_chunk **current_trace_chunk)
769 {
770 ASSERT_LOCKED(session->lock);
771 return _session_set_trace_chunk_no_lock_check(session, new_trace_chunk,
772 current_trace_chunk);
773 }
774
775 static
776 void session_notify_destruction(const struct ltt_session *session)
777 {
778 size_t i;
779 const size_t count = lttng_dynamic_array_get_count(
780 &session->destroy_notifiers);
781
782 for (i = 0; i < count; i++) {
783 const struct ltt_session_destroy_notifier_element *element =
784 lttng_dynamic_array_get_element(
785 &session->destroy_notifiers, i);
786
787 element->notifier(session, element->user_data);
788 }
789 }
790
791 static
792 void session_release(struct urcu_ref *ref)
793 {
794 int ret;
795 struct ltt_ust_session *usess;
796 struct ltt_kernel_session *ksess;
797 struct ltt_session *session = container_of(ref, typeof(*session), ref);
798 const bool session_published = session->published;
799
800 assert(!session->chunk_being_archived);
801
802 usess = session->ust_session;
803 ksess = session->kernel_session;
804
805 /* Clean kernel session teardown, keeping data for destroy notifier. */
806 kernel_destroy_session(ksess);
807
808 /* UST session teardown, keeping data for destroy notifier. */
809 if (usess) {
810 /* Close any relayd session */
811 consumer_output_send_destroy_relayd(usess->consumer);
812
813 /* Destroy every UST application related to this session. */
814 ret = ust_app_destroy_trace_all(usess);
815 if (ret) {
816 ERR("Error in ust_app_destroy_trace_all");
817 }
818
819 /* Clean up the rest, keeping destroy notifier data. */
820 trace_ust_destroy_session(usess);
821 }
822
823 /*
824 * Must notify the kernel thread here to update it's poll set in order to
825 * remove the channel(s)' fd just destroyed.
826 */
827 ret = notify_thread_pipe(kernel_poll_pipe[1]);
828 if (ret < 0) {
829 PERROR("write kernel poll pipe");
830 }
831
832 DBG("Destroying session %s (id %" PRIu64 ")", session->name, session->id);
833
834 consumer_output_put(session->consumer);
835 snapshot_destroy(&session->snapshot);
836
837 pthread_mutex_destroy(&session->lock);
838
839 if (session_published) {
840 ASSERT_LOCKED(ltt_session_list.lock);
841 del_session_list(session);
842 del_session_ht(session);
843 }
844 session_notify_destruction(session);
845
846 kernel_free_session(ksess);
847 session->kernel_session = NULL;
848 if (usess) {
849 trace_ust_free_session(usess);
850 session->ust_session = NULL;
851 }
852 lttng_dynamic_array_reset(&session->destroy_notifiers);
853 free(session->last_archived_chunk_name);
854 free(session->base_path);
855 free(session);
856 if (session_published) {
857 /*
858 * Broadcast after free-ing to ensure the memory is
859 * reclaimed before the main thread exits.
860 */
861 pthread_cond_broadcast(&ltt_session_list.removal_cond);
862 }
863 }
864
865 /*
866 * Acquire a reference to a session.
867 * This function may fail (return false); its return value must be checked.
868 */
869 bool session_get(struct ltt_session *session)
870 {
871 return urcu_ref_get_unless_zero(&session->ref);
872 }
873
874 /*
875 * Release a reference to a session.
876 */
877 void session_put(struct ltt_session *session)
878 {
879 if (!session) {
880 return;
881 }
882 /*
883 * The session list lock must be held as any session_put()
884 * may cause the removal of the session from the session_list.
885 */
886 ASSERT_LOCKED(ltt_session_list.lock);
887 assert(session->ref.refcount);
888 urcu_ref_put(&session->ref, session_release);
889 }
890
891 /*
892 * Destroy a session.
893 *
894 * This method does not immediately release/free the session as other
895 * components may still hold a reference to the session. However,
896 * the session should no longer be presented to the user.
897 *
898 * Releases the session list's reference to the session
899 * and marks it as destroyed. Iterations on the session list should be
900 * mindful of the "destroyed" flag.
901 */
902 void session_destroy(struct ltt_session *session)
903 {
904 assert(!session->destroyed);
905 session->destroyed = true;
906 session_put(session);
907 }
908
909 int session_add_destroy_notifier(struct ltt_session *session,
910 ltt_session_destroy_notifier notifier, void *user_data)
911 {
912 const struct ltt_session_destroy_notifier_element element = {
913 .notifier = notifier,
914 .user_data = user_data
915 };
916
917 return lttng_dynamic_array_add_element(&session->destroy_notifiers,
918 &element);
919 }
920
921 /*
922 * Return a ltt_session structure ptr that matches name. If no session found,
923 * NULL is returned. This must be called with the session list lock held using
924 * session_lock_list and session_unlock_list.
925 * A reference to the session is implicitly acquired by this function.
926 */
927 struct ltt_session *session_find_by_name(const char *name)
928 {
929 struct ltt_session *iter;
930
931 assert(name);
932 ASSERT_LOCKED(ltt_session_list.lock);
933
934 DBG2("Trying to find session by name %s", name);
935
936 cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
937 if (!strncmp(iter->name, name, NAME_MAX) &&
938 !iter->destroyed) {
939 goto found;
940 }
941 }
942
943 return NULL;
944 found:
945 return session_get(iter) ? iter : NULL;
946 }
947
948 /*
949 * Return an ltt_session that matches the id. If no session is found,
950 * NULL is returned. This must be called with rcu_read_lock and
951 * session list lock held (to guarantee the lifetime of the session).
952 */
953 struct ltt_session *session_find_by_id(uint64_t id)
954 {
955 struct lttng_ht_node_u64 *node;
956 struct lttng_ht_iter iter;
957 struct ltt_session *ls;
958
959 ASSERT_LOCKED(ltt_session_list.lock);
960
961 if (!ltt_sessions_ht_by_id) {
962 goto end;
963 }
964
965 lttng_ht_lookup(ltt_sessions_ht_by_id, &id, &iter);
966 node = lttng_ht_iter_get_node_u64(&iter);
967 if (node == NULL) {
968 goto end;
969 }
970 ls = caa_container_of(node, struct ltt_session, node);
971
972 DBG3("Session %" PRIu64 " found by id.", id);
973 return session_get(ls) ? ls : NULL;
974
975 end:
976 DBG3("Session %" PRIu64 " NOT found by id", id);
977 return NULL;
978 }
979
980 /*
981 * Create a new session and add it to the session list.
982 * Session list lock must be held by the caller.
983 */
984 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
985 const char *base_path, struct ltt_session **out_session)
986 {
987 int ret;
988 enum lttng_error_code ret_code;
989 struct ltt_session *new_session = NULL;
990
991 ASSERT_LOCKED(ltt_session_list.lock);
992 if (name) {
993 struct ltt_session *clashing_session;
994
995 clashing_session = session_find_by_name(name);
996 if (clashing_session) {
997 session_put(clashing_session);
998 ret_code = LTTNG_ERR_EXIST_SESS;
999 goto error;
1000 }
1001 }
1002 new_session = zmalloc(sizeof(struct ltt_session));
1003 if (!new_session) {
1004 PERROR("Failed to allocate an ltt_session structure");
1005 ret_code = LTTNG_ERR_NOMEM;
1006 goto error;
1007 }
1008
1009 lttng_dynamic_array_init(&new_session->destroy_notifiers,
1010 sizeof(struct ltt_session_destroy_notifier_element),
1011 NULL);
1012 urcu_ref_init(&new_session->ref);
1013 pthread_mutex_init(&new_session->lock, NULL);
1014
1015 new_session->creation_time = time(NULL);
1016 if (new_session->creation_time == (time_t) -1) {
1017 PERROR("Failed to sample session creation time");
1018 ret_code = LTTNG_ERR_SESSION_FAIL;
1019 goto error;
1020 }
1021
1022 /* Create default consumer output. */
1023 new_session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
1024 if (new_session->consumer == NULL) {
1025 ret_code = LTTNG_ERR_NOMEM;
1026 goto error;
1027 }
1028
1029 if (name) {
1030 ret = lttng_strncpy(new_session->name, name, sizeof(new_session->name));
1031 if (ret) {
1032 ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
1033 goto error;
1034 }
1035 ret = validate_name(name);
1036 if (ret < 0) {
1037 ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
1038 goto error;
1039 }
1040 } else {
1041 int i = 0;
1042 bool found_name = false;
1043 char datetime[16];
1044 struct tm *timeinfo;
1045
1046 timeinfo = localtime(&new_session->creation_time);
1047 if (!timeinfo) {
1048 ret_code = LTTNG_ERR_SESSION_FAIL;
1049 goto error;
1050 }
1051 strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
1052 for (i = 0; i < INT_MAX; i++) {
1053 struct ltt_session *clashing_session;
1054
1055 if (i == 0) {
1056 ret = snprintf(new_session->name,
1057 sizeof(new_session->name),
1058 "%s-%s",
1059 DEFAULT_SESSION_NAME,
1060 datetime);
1061 } else {
1062 ret = snprintf(new_session->name,
1063 sizeof(new_session->name),
1064 "%s%d-%s",
1065 DEFAULT_SESSION_NAME, i,
1066 datetime);
1067 }
1068 new_session->name_contains_creation_time = true;
1069 if (ret == -1 || ret >= sizeof(new_session->name)) {
1070 /*
1071 * Null-terminate in case the name is used
1072 * in logging statements.
1073 */
1074 new_session->name[sizeof(new_session->name) - 1] = '\0';
1075 ret_code = LTTNG_ERR_SESSION_FAIL;
1076 goto error;
1077 }
1078
1079 clashing_session =
1080 session_find_by_name(new_session->name);
1081 session_put(clashing_session);
1082 if (!clashing_session) {
1083 found_name = true;
1084 break;
1085 }
1086 }
1087 if (found_name) {
1088 DBG("Generated session name \"%s\"", new_session->name);
1089 new_session->has_auto_generated_name = true;
1090 } else {
1091 ERR("Failed to auto-generate a session name");
1092 ret_code = LTTNG_ERR_SESSION_FAIL;
1093 goto error;
1094 }
1095 }
1096
1097 ret = gethostname(new_session->hostname, sizeof(new_session->hostname));
1098 if (ret < 0) {
1099 if (errno == ENAMETOOLONG) {
1100 new_session->hostname[sizeof(new_session->hostname) - 1] = '\0';
1101 ERR("Hostname exceeds the maximal permitted length and has been truncated to %s",
1102 new_session->hostname);
1103 } else {
1104 ret_code = LTTNG_ERR_SESSION_FAIL;
1105 goto error;
1106 }
1107 }
1108
1109 if (base_path) {
1110 new_session->base_path = strdup(base_path);
1111 if (!new_session->base_path) {
1112 ERR("Failed to allocate base path of session \"%s\"",
1113 name);
1114 ret_code = LTTNG_ERR_SESSION_FAIL;
1115 goto error;
1116 }
1117 }
1118
1119 new_session->uid = uid;
1120 new_session->gid = gid;
1121
1122 ret = snapshot_init(&new_session->snapshot);
1123 if (ret < 0) {
1124 ret_code = LTTNG_ERR_NOMEM;
1125 goto error;
1126 }
1127
1128 new_session->rotation_state = LTTNG_ROTATION_STATE_NO_ROTATION;
1129
1130 /* Add new session to the session list. */
1131 new_session->id = add_session_list(new_session);
1132
1133 /*
1134 * Add the new session to the ltt_sessions_ht_by_id.
1135 * No ownership is taken by the hash table; it is merely
1136 * a wrapper around the session list used for faster access
1137 * by session id.
1138 */
1139 add_session_ht(new_session);
1140 new_session->published = true;
1141
1142 /*
1143 * Consumer is left to NULL since the create_session_uri command will
1144 * set it up and, if valid, assign it to the session.
1145 */
1146 DBG("Tracing session %s created with ID %" PRIu64 " by uid = %d, gid = %d",
1147 new_session->name, new_session->id, new_session->uid,
1148 new_session->gid);
1149 ret_code = LTTNG_OK;
1150 end:
1151 if (new_session) {
1152 (void) session_get(new_session);
1153 *out_session = new_session;
1154 }
1155 return ret_code;
1156 error:
1157 session_put(new_session);
1158 new_session = NULL;
1159 goto end;
1160 }
1161
1162 /*
1163 * Check if the UID or GID match the session. Root user has access to all
1164 * sessions.
1165 */
1166 int session_access_ok(struct ltt_session *session, uid_t uid, gid_t gid)
1167 {
1168 assert(session);
1169
1170 if (uid != session->uid && gid != session->gid && uid != 0) {
1171 return 0;
1172 } else {
1173 return 1;
1174 }
1175 }
1176
1177 /*
1178 * Set a session's rotation state and reset all associated state.
1179 *
1180 * This function resets the rotation state (check timers, pending
1181 * flags, etc.) and sets the result of the last rotation. The result
1182 * can be queries by a liblttng-ctl client.
1183 *
1184 * Be careful of the result passed to this function. For instance,
1185 * on failure to launch a rotation, a client will expect the rotation
1186 * state to be set to "NO_ROTATION". If an error occured while the
1187 * rotation was "ONGOING", result should be set to "ERROR", which will
1188 * allow a client to report it.
1189 *
1190 * Must be called with the session and session_list locks held.
1191 */
1192 int session_reset_rotation_state(struct ltt_session *session,
1193 enum lttng_rotation_state result)
1194 {
1195 int ret = 0;
1196
1197 ASSERT_LOCKED(ltt_session_list.lock);
1198 ASSERT_LOCKED(session->lock);
1199
1200 session->rotation_state = result;
1201 if (session->rotation_pending_check_timer_enabled) {
1202 ret = timer_session_rotation_pending_check_stop(session);
1203 }
1204 if (session->chunk_being_archived) {
1205 uint64_t chunk_id;
1206 enum lttng_trace_chunk_status chunk_status;
1207
1208 chunk_status = lttng_trace_chunk_get_id(
1209 session->chunk_being_archived,
1210 &chunk_id);
1211 assert(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
1212 LTTNG_OPTIONAL_SET(&session->last_archived_chunk_id,
1213 chunk_id);
1214 lttng_trace_chunk_put(session->chunk_being_archived);
1215 session->chunk_being_archived = NULL;
1216 }
1217 return ret;
1218 }
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