Bump minimum kernel version to 2.6.30 to use EFD_SEMAPHORE
[lttng-tools.git] / src / bin / lttng-sessiond / session.cpp
1 /*
2 * Copyright (C) 2011 EfficiOS Inc.
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8 #define _LGPL_SOURCE
9 #include <limits.h>
10 #include <inttypes.h>
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <string.h>
14 #include <sys/stat.h>
15 #include <urcu.h>
16 #include <dirent.h>
17 #include <sys/types.h>
18 #include <pthread.h>
19
20 #include <common/common.hpp>
21 #include <common/utils.hpp>
22 #include <common/trace-chunk.hpp>
23 #include <common/sessiond-comm/sessiond-comm.hpp>
24 #include <lttng/location-internal.hpp>
25 #include "lttng-sessiond.hpp"
26 #include "kernel.hpp"
27
28 #include "session.hpp"
29 #include "utils.hpp"
30 #include "trace-ust.hpp"
31 #include "timer.hpp"
32 #include "cmd.hpp"
33
34 struct ltt_session_destroy_notifier_element {
35 ltt_session_destroy_notifier notifier;
36 void *user_data;
37 };
38
39 struct ltt_session_clear_notifier_element {
40 ltt_session_clear_notifier notifier;
41 void *user_data;
42 };
43
44 /*
45 * NOTES:
46 *
47 * No ltt_session.lock is taken here because those data structure are widely
48 * spread across the lttng-tools code base so before calling functions below
49 * that can read/write a session, the caller MUST acquire the session lock
50 * using session_lock() and session_unlock().
51 */
52
53 /*
54 * Init tracing session list.
55 *
56 * Please see session.h for more explanation and correct usage of the list.
57 */
58 static struct ltt_session_list ltt_session_list = {
59 .lock = PTHREAD_MUTEX_INITIALIZER,
60 .removal_cond = PTHREAD_COND_INITIALIZER,
61 .next_uuid = 0,
62 .head = CDS_LIST_HEAD_INIT(ltt_session_list.head),
63 };
64
65 /* These characters are forbidden in a session name. Used by validate_name. */
66 static const char *forbidden_name_chars = "/";
67
68 /* Global hash table to keep the sessions, indexed by id. */
69 static struct lttng_ht *ltt_sessions_ht_by_id = NULL;
70 /* Global hash table to keep the sessions, indexed by name. */
71 static struct lttng_ht *ltt_sessions_ht_by_name = NULL;
72
73 /*
74 * Validate the session name for forbidden characters.
75 *
76 * Return 0 on success else -1 meaning a forbidden char. has been found.
77 */
78 static int validate_name(const char *name)
79 {
80 int ret;
81 char *tok, *tmp_name;
82
83 LTTNG_ASSERT(name);
84
85 tmp_name = strdup(name);
86 if (!tmp_name) {
87 /* ENOMEM here. */
88 ret = -1;
89 goto error;
90 }
91
92 tok = strpbrk(tmp_name, forbidden_name_chars);
93 if (tok) {
94 DBG("Session name %s contains a forbidden character", name);
95 /* Forbidden character has been found. */
96 ret = -1;
97 goto error;
98 }
99 ret = 0;
100
101 error:
102 free(tmp_name);
103 return ret;
104 }
105
106 /*
107 * Add a ltt_session structure to the global list.
108 *
109 * The caller MUST acquire the session list lock before.
110 * Returns the unique identifier for the session.
111 */
112 static uint64_t add_session_list(struct ltt_session *ls)
113 {
114 LTTNG_ASSERT(ls);
115
116 cds_list_add(&ls->list, &ltt_session_list.head);
117 return ltt_session_list.next_uuid++;
118 }
119
120 /*
121 * Delete a ltt_session structure to the global list.
122 *
123 * The caller MUST acquire the session list lock before.
124 */
125 static void del_session_list(struct ltt_session *ls)
126 {
127 LTTNG_ASSERT(ls);
128
129 cds_list_del(&ls->list);
130 }
131
132 /*
133 * Return a pointer to the session list.
134 */
135 struct ltt_session_list *session_get_list(void)
136 {
137 return &ltt_session_list;
138 }
139
140 /*
141 * Returns once the session list is empty.
142 */
143 void session_list_wait_empty(void)
144 {
145 pthread_mutex_lock(&ltt_session_list.lock);
146 while (!cds_list_empty(&ltt_session_list.head)) {
147 pthread_cond_wait(&ltt_session_list.removal_cond,
148 &ltt_session_list.lock);
149 }
150 pthread_mutex_unlock(&ltt_session_list.lock);
151 }
152
153 /*
154 * Acquire session list lock
155 */
156 void session_lock_list(void)
157 {
158 pthread_mutex_lock(&ltt_session_list.lock);
159 }
160
161 /*
162 * Try to acquire session list lock
163 */
164 int session_trylock_list(void)
165 {
166 return pthread_mutex_trylock(&ltt_session_list.lock);
167 }
168
169 /*
170 * Release session list lock
171 */
172 void session_unlock_list(void)
173 {
174 pthread_mutex_unlock(&ltt_session_list.lock);
175 }
176
177 /*
178 * Get the session's consumer destination type.
179 *
180 * The caller must hold the session lock.
181 */
182 enum consumer_dst_type session_get_consumer_destination_type(
183 const struct ltt_session *session)
184 {
185 /*
186 * The output information is duplicated in both of those session types.
187 * Hence, it doesn't matter from which it is retrieved. However, it is
188 * possible for only one of them to be set.
189 */
190 return session->kernel_session ?
191 session->kernel_session->consumer->type :
192 session->ust_session->consumer->type;
193 }
194
195 /*
196 * Get the session's consumer network hostname.
197 * The caller must ensure that the destination is of type "net".
198 *
199 * The caller must hold the session lock.
200 */
201 const char *session_get_net_consumer_hostname(const struct ltt_session *session)
202 {
203 const char *hostname = NULL;
204 const struct consumer_output *output;
205
206 output = session->kernel_session ?
207 session->kernel_session->consumer :
208 session->ust_session->consumer;
209
210 /*
211 * hostname is assumed to be the same for both control and data
212 * connections.
213 */
214 switch (output->dst.net.control.dtype) {
215 case LTTNG_DST_IPV4:
216 hostname = output->dst.net.control.dst.ipv4;
217 break;
218 case LTTNG_DST_IPV6:
219 hostname = output->dst.net.control.dst.ipv6;
220 break;
221 default:
222 abort();
223 }
224 return hostname;
225 }
226
227 /*
228 * Get the session's consumer network control and data ports.
229 * The caller must ensure that the destination is of type "net".
230 *
231 * The caller must hold the session lock.
232 */
233 void session_get_net_consumer_ports(const struct ltt_session *session,
234 uint16_t *control_port, uint16_t *data_port)
235 {
236 const struct consumer_output *output;
237
238 output = session->kernel_session ?
239 session->kernel_session->consumer :
240 session->ust_session->consumer;
241 *control_port = output->dst.net.control.port;
242 *data_port = output->dst.net.data.port;
243 }
244
245 /*
246 * Get the location of the latest trace archive produced by a rotation.
247 *
248 * The caller must hold the session lock.
249 */
250 struct lttng_trace_archive_location *session_get_trace_archive_location(
251 const struct ltt_session *session)
252 {
253 int ret;
254 struct lttng_trace_archive_location *location = NULL;
255 char *chunk_path = NULL;
256
257 if (session->rotation_state != LTTNG_ROTATION_STATE_COMPLETED ||
258 !session->last_archived_chunk_name) {
259 goto end;
260 }
261
262 switch (session_get_consumer_destination_type(session)) {
263 case CONSUMER_DST_LOCAL:
264 ret = asprintf(&chunk_path,
265 "%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 location = lttng_trace_archive_location_local_create(
272 chunk_path);
273 break;
274 case CONSUMER_DST_NET:
275 {
276 const char *hostname;
277 uint16_t control_port, data_port;
278
279 hostname = session_get_net_consumer_hostname(session);
280 session_get_net_consumer_ports(session,
281 &control_port,
282 &data_port);
283 location = lttng_trace_archive_location_relay_create(
284 hostname,
285 LTTNG_TRACE_ARCHIVE_LOCATION_RELAY_PROTOCOL_TYPE_TCP,
286 control_port, data_port, session->last_chunk_path);
287 break;
288 }
289 default:
290 abort();
291 }
292 end:
293 free(chunk_path);
294 return location;
295 }
296
297 /*
298 * Allocate the ltt_sessions_ht_by_id and ltt_sessions_ht_by_name HT.
299 *
300 * The session list lock must be held.
301 */
302 static int ltt_sessions_ht_alloc(void)
303 {
304 int ret = 0;
305
306 DBG("Allocating ltt_sessions_ht_by_id");
307 ltt_sessions_ht_by_id = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
308 if (!ltt_sessions_ht_by_id) {
309 ret = -1;
310 ERR("Failed to allocate ltt_sessions_ht_by_id");
311 goto end;
312 }
313
314 DBG("Allocating ltt_sessions_ht_by_name");
315 ltt_sessions_ht_by_name = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
316 if (!ltt_sessions_ht_by_name) {
317 ret = -1;
318 ERR("Failed to allocate ltt_sessions_ht_by_name");
319 goto end;
320 }
321
322 end:
323 return ret;
324 }
325
326 /*
327 * Destroy the ltt_sessions_ht_by_id HT.
328 *
329 * The session list lock must be held.
330 */
331 static void ltt_sessions_ht_destroy(void)
332 {
333 if (ltt_sessions_ht_by_id) {
334 lttng_ht_destroy(ltt_sessions_ht_by_id);
335 ltt_sessions_ht_by_id = NULL;
336 }
337
338 if (ltt_sessions_ht_by_name) {
339 lttng_ht_destroy(ltt_sessions_ht_by_name);
340 ltt_sessions_ht_by_name = NULL;
341 }
342
343 return;
344 }
345
346 /*
347 * Add a ltt_session to the ltt_sessions_ht_by_id and ltt_sessions_ht_by_name.
348 * If unallocated, the ltt_sessions_ht_by_id and ltt_sessions_ht_by_name. HTs
349 * are allocated. The session list lock must be held.
350 */
351 static void add_session_ht(struct ltt_session *ls)
352 {
353 int ret;
354
355 LTTNG_ASSERT(ls);
356
357 if (!ltt_sessions_ht_by_id) {
358 ret = ltt_sessions_ht_alloc();
359 if (ret) {
360 ERR("Error allocating the sessions HT");
361 goto end;
362 }
363 }
364
365 /* Should always be present with ltt_sessions_ht_by_id. */
366 LTTNG_ASSERT(ltt_sessions_ht_by_name);
367
368 lttng_ht_node_init_u64(&ls->node, ls->id);
369 lttng_ht_add_unique_u64(ltt_sessions_ht_by_id, &ls->node);
370
371 lttng_ht_node_init_str(&ls->node_by_name, ls->name);
372 lttng_ht_add_unique_str(ltt_sessions_ht_by_name, &ls->node_by_name);
373
374 end:
375 return;
376 }
377
378 /*
379 * Test if ltt_sessions_ht_by_id/name are empty.
380 * Return `false` if hash table objects are null.
381 * The session list lock must be held.
382 */
383 static bool ltt_sessions_ht_empty(void)
384 {
385 bool empty = false;
386
387 if (!ltt_sessions_ht_by_id) {
388 /* The hash tables do not exist yet. */
389 goto end;
390 }
391
392 LTTNG_ASSERT(ltt_sessions_ht_by_name);
393
394 if (lttng_ht_get_count(ltt_sessions_ht_by_id) != 0) {
395 /* Not empty.*/
396 goto end;
397 }
398
399 /*
400 * At this point it is expected that the `ltt_sessions_ht_by_name` ht is
401 * empty.
402 *
403 * The removal from both hash tables is done in two different
404 * places:
405 * - removal from `ltt_sessions_ht_by_name` is done during
406 * `session_destroy()`
407 * - removal from `ltt_sessions_ht_by_id` is done later
408 * in `session_release()` on the last reference put.
409 *
410 * This means that it is possible for `ltt_sessions_ht_by_name` to be
411 * empty but for `ltt_sessions_ht_by_id` to still contain objects when
412 * multiple sessions exists. The reverse is false, hence this sanity
413 * check.
414 */
415 LTTNG_ASSERT(lttng_ht_get_count(ltt_sessions_ht_by_name) == 0);
416 empty = true;
417 end:
418 return empty;
419 }
420
421 /*
422 * Remove a ltt_session from the ltt_sessions_ht_by_id.
423 * If empty, the ltt_sessions_ht_by_id/name HTs are freed.
424 * The session list lock must be held.
425 */
426 static void del_session_ht(struct ltt_session *ls)
427 {
428 struct lttng_ht_iter iter;
429 int ret;
430
431 LTTNG_ASSERT(ls);
432 LTTNG_ASSERT(ltt_sessions_ht_by_id);
433 LTTNG_ASSERT(ltt_sessions_ht_by_name);
434
435 iter.iter.node = &ls->node.node;
436 ret = lttng_ht_del(ltt_sessions_ht_by_id, &iter);
437 LTTNG_ASSERT(!ret);
438
439 if (ltt_sessions_ht_empty()) {
440 DBG("Empty ltt_sessions_ht_by_id/name, destroying hast tables");
441 ltt_sessions_ht_destroy();
442 }
443 }
444
445 /*
446 * Acquire session lock
447 */
448 void session_lock(struct ltt_session *session)
449 {
450 LTTNG_ASSERT(session);
451
452 pthread_mutex_lock(&session->lock);
453 }
454
455 /*
456 * Release session lock
457 */
458 void session_unlock(struct ltt_session *session)
459 {
460 LTTNG_ASSERT(session);
461
462 pthread_mutex_unlock(&session->lock);
463 }
464
465 static
466 int _session_set_trace_chunk_no_lock_check(struct ltt_session *session,
467 struct lttng_trace_chunk *new_trace_chunk,
468 struct lttng_trace_chunk **_current_trace_chunk)
469 {
470 int ret = 0;
471 unsigned int i, refs_to_acquire = 0, refs_acquired = 0, refs_to_release = 0;
472 struct cds_lfht_iter iter;
473 struct consumer_socket *socket;
474 struct lttng_trace_chunk *current_trace_chunk;
475 uint64_t chunk_id;
476 enum lttng_trace_chunk_status chunk_status;
477
478 rcu_read_lock();
479 /*
480 * Ownership of current trace chunk is transferred to
481 * `current_trace_chunk`.
482 */
483 current_trace_chunk = session->current_trace_chunk;
484 session->current_trace_chunk = NULL;
485 if (session->ust_session) {
486 lttng_trace_chunk_put(
487 session->ust_session->current_trace_chunk);
488 session->ust_session->current_trace_chunk = NULL;
489 }
490 if (session->kernel_session) {
491 lttng_trace_chunk_put(
492 session->kernel_session->current_trace_chunk);
493 session->kernel_session->current_trace_chunk = NULL;
494 }
495 if (!new_trace_chunk) {
496 ret = 0;
497 goto end;
498 }
499 chunk_status = lttng_trace_chunk_get_id(new_trace_chunk, &chunk_id);
500 LTTNG_ASSERT(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
501
502 refs_to_acquire = 1;
503 refs_to_acquire += !!session->ust_session;
504 refs_to_acquire += !!session->kernel_session;
505
506 for (refs_acquired = 0; refs_acquired < refs_to_acquire;
507 refs_acquired++) {
508 if (!lttng_trace_chunk_get(new_trace_chunk)) {
509 ERR("Failed to acquire reference to new trace chunk of session \"%s\"",
510 session->name);
511 goto error;
512 }
513 }
514
515 if (session->ust_session) {
516 const uint64_t relayd_id =
517 session->ust_session->consumer->net_seq_index;
518 const bool is_local_trace =
519 session->ust_session->consumer->type ==
520 CONSUMER_DST_LOCAL;
521
522 session->ust_session->current_trace_chunk = new_trace_chunk;
523 if (is_local_trace) {
524 enum lttng_error_code ret_error_code;
525
526 ret_error_code = ust_app_create_channel_subdirectories(
527 session->ust_session);
528 if (ret_error_code != LTTNG_OK) {
529 goto error;
530 }
531 }
532 cds_lfht_for_each_entry(
533 session->ust_session->consumer->socks->ht,
534 &iter, socket, node.node) {
535 pthread_mutex_lock(socket->lock);
536 ret = consumer_create_trace_chunk(socket,
537 relayd_id,
538 session->id, new_trace_chunk,
539 DEFAULT_UST_TRACE_DIR);
540 pthread_mutex_unlock(socket->lock);
541 if (ret) {
542 goto error;
543 }
544 }
545 }
546 if (session->kernel_session) {
547 const uint64_t relayd_id =
548 session->kernel_session->consumer->net_seq_index;
549 const bool is_local_trace =
550 session->kernel_session->consumer->type ==
551 CONSUMER_DST_LOCAL;
552
553 session->kernel_session->current_trace_chunk = new_trace_chunk;
554 if (is_local_trace) {
555 enum lttng_error_code ret_error_code;
556
557 ret_error_code = kernel_create_channel_subdirectories(
558 session->kernel_session);
559 if (ret_error_code != LTTNG_OK) {
560 goto error;
561 }
562 }
563 cds_lfht_for_each_entry(
564 session->kernel_session->consumer->socks->ht,
565 &iter, socket, node.node) {
566 pthread_mutex_lock(socket->lock);
567 ret = consumer_create_trace_chunk(socket,
568 relayd_id,
569 session->id, new_trace_chunk,
570 DEFAULT_KERNEL_TRACE_DIR);
571 pthread_mutex_unlock(socket->lock);
572 if (ret) {
573 goto error;
574 }
575 }
576 }
577
578 /*
579 * Update local current trace chunk state last, only if all remote
580 * creations succeeded.
581 */
582 session->current_trace_chunk = new_trace_chunk;
583 LTTNG_OPTIONAL_SET(&session->most_recent_chunk_id, chunk_id);
584 end:
585 if (_current_trace_chunk) {
586 *_current_trace_chunk = current_trace_chunk;
587 current_trace_chunk = NULL;
588 }
589 end_no_move:
590 rcu_read_unlock();
591 lttng_trace_chunk_put(current_trace_chunk);
592 return ret;
593 error:
594 if (session->ust_session) {
595 session->ust_session->current_trace_chunk = NULL;
596 }
597 if (session->kernel_session) {
598 session->kernel_session->current_trace_chunk = NULL;
599 }
600 /*
601 * Release references taken in the case where all references could not
602 * be acquired.
603 */
604 refs_to_release = refs_to_acquire - refs_acquired;
605 for (i = 0; i < refs_to_release; i++) {
606 lttng_trace_chunk_put(new_trace_chunk);
607 }
608 ret = -1;
609 goto end_no_move;
610 }
611
612 struct lttng_trace_chunk *session_create_new_trace_chunk(
613 const struct ltt_session *session,
614 const struct consumer_output *consumer_output_override,
615 const char *session_base_path_override,
616 const char *chunk_name_override)
617 {
618 int ret;
619 struct lttng_trace_chunk *trace_chunk = NULL;
620 enum lttng_trace_chunk_status chunk_status;
621 const time_t chunk_creation_ts = time(NULL);
622 bool is_local_trace;
623 const char *base_path;
624 struct lttng_directory_handle *session_output_directory = NULL;
625 const struct lttng_credentials session_credentials = {
626 .uid = LTTNG_OPTIONAL_INIT_VALUE(session->uid),
627 .gid = LTTNG_OPTIONAL_INIT_VALUE(session->gid),
628 };
629 uint64_t next_chunk_id;
630 const struct consumer_output *output;
631 const char *new_path;
632
633 if (consumer_output_override) {
634 output = consumer_output_override;
635 } else {
636 LTTNG_ASSERT(session->ust_session || session->kernel_session);
637 output = session->ust_session ?
638 session->ust_session->consumer :
639 session->kernel_session->consumer;
640 }
641
642 is_local_trace = output->type == CONSUMER_DST_LOCAL;
643 base_path = session_base_path_override ? :
644 consumer_output_get_base_path(output);
645
646 if (chunk_creation_ts == (time_t) -1) {
647 PERROR("Failed to sample time while creation session \"%s\" trace chunk",
648 session->name);
649 goto error;
650 }
651
652 next_chunk_id = session->most_recent_chunk_id.is_set ?
653 session->most_recent_chunk_id.value + 1 : 0;
654
655 if (session->current_trace_chunk &&
656 !lttng_trace_chunk_get_name_overridden(session->current_trace_chunk)) {
657 chunk_status = lttng_trace_chunk_rename_path(session->current_trace_chunk,
658 DEFAULT_CHUNK_TMP_OLD_DIRECTORY);
659 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
660 goto error;
661 }
662 }
663 if (!session->current_trace_chunk) {
664 if (!session->rotated) {
665 new_path = "";
666 } else {
667 new_path = NULL;
668 }
669 } else {
670 new_path = DEFAULT_CHUNK_TMP_NEW_DIRECTORY;
671 }
672
673 trace_chunk = lttng_trace_chunk_create(next_chunk_id,
674 chunk_creation_ts, new_path);
675 if (!trace_chunk) {
676 goto error;
677 }
678
679 if (chunk_name_override) {
680 chunk_status = lttng_trace_chunk_override_name(trace_chunk,
681 chunk_name_override);
682 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
683 goto error;
684 }
685 }
686
687 if (!is_local_trace) {
688 /*
689 * No need to set crendentials and output directory
690 * for remote trace chunks.
691 */
692 goto end;
693 }
694
695 chunk_status = lttng_trace_chunk_set_credentials(trace_chunk,
696 &session_credentials);
697 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
698 goto error;
699 }
700
701 DBG("Creating base output directory of session \"%s\" at %s",
702 session->name, base_path);
703 ret = utils_mkdir_recursive(base_path, S_IRWXU | S_IRWXG,
704 session->uid, session->gid);
705 if (ret) {
706 goto error;
707 }
708 session_output_directory = lttng_directory_handle_create(base_path);
709 if (!session_output_directory) {
710 goto error;
711 }
712 chunk_status = lttng_trace_chunk_set_as_owner(trace_chunk,
713 session_output_directory);
714 lttng_directory_handle_put(session_output_directory);
715 session_output_directory = NULL;
716 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
717 goto error;
718 }
719 end:
720 return trace_chunk;
721 error:
722 lttng_directory_handle_put(session_output_directory);
723 lttng_trace_chunk_put(trace_chunk);
724 trace_chunk = NULL;
725 goto end;
726 }
727
728 int session_close_trace_chunk(struct ltt_session *session,
729 struct lttng_trace_chunk *trace_chunk,
730 enum lttng_trace_chunk_command_type close_command,
731 char *closed_trace_chunk_path)
732 {
733 int ret = 0;
734 bool error_occurred = false;
735 struct cds_lfht_iter iter;
736 struct consumer_socket *socket;
737 enum lttng_trace_chunk_status chunk_status;
738 const time_t chunk_close_timestamp = time(NULL);
739 const char *new_path;
740
741 chunk_status = lttng_trace_chunk_set_close_command(
742 trace_chunk, close_command);
743 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
744 ret = -1;
745 goto end;
746 }
747
748 if (chunk_close_timestamp == (time_t) -1) {
749 ERR("Failed to sample the close timestamp of the current trace chunk of session \"%s\"",
750 session->name);
751 ret = -1;
752 goto end;
753 }
754
755 if (close_command == LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE && !session->rotated) {
756 /* New chunk stays in session output directory. */
757 new_path = "";
758 } else {
759 /* Use chunk name for new chunk. */
760 new_path = NULL;
761 }
762 if (session->current_trace_chunk &&
763 !lttng_trace_chunk_get_name_overridden(session->current_trace_chunk)) {
764 /* Rename new chunk path. */
765 chunk_status = lttng_trace_chunk_rename_path(session->current_trace_chunk,
766 new_path);
767 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
768 ret = -1;
769 goto end;
770 }
771 }
772 if (!lttng_trace_chunk_get_name_overridden(trace_chunk) &&
773 close_command == LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION) {
774 const char *old_path;
775
776 if (!session->rotated) {
777 old_path = "";
778 } else {
779 old_path = NULL;
780 }
781 /* We need to move back the .tmp_old_chunk to its rightful place. */
782 chunk_status = lttng_trace_chunk_rename_path(trace_chunk,
783 old_path);
784 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
785 ret = -1;
786 goto end;
787 }
788 }
789 if (close_command == LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED) {
790 session->rotated = true;
791 }
792 chunk_status = lttng_trace_chunk_set_close_timestamp(trace_chunk,
793 chunk_close_timestamp);
794 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
795 ERR("Failed to set the close timestamp of the current trace chunk of session \"%s\"",
796 session->name);
797 ret = -1;
798 goto end;
799 }
800
801 if (session->ust_session) {
802 const uint64_t relayd_id =
803 session->ust_session->consumer->net_seq_index;
804
805 cds_lfht_for_each_entry(
806 session->ust_session->consumer->socks->ht,
807 &iter, socket, node.node) {
808 pthread_mutex_lock(socket->lock);
809 ret = consumer_close_trace_chunk(socket,
810 relayd_id,
811 session->id,
812 trace_chunk, closed_trace_chunk_path);
813 pthread_mutex_unlock(socket->lock);
814 if (ret) {
815 ERR("Failed to close trace chunk on user space consumer");
816 error_occurred = true;
817 }
818 }
819 }
820 if (session->kernel_session) {
821 const uint64_t relayd_id =
822 session->kernel_session->consumer->net_seq_index;
823
824 cds_lfht_for_each_entry(
825 session->kernel_session->consumer->socks->ht,
826 &iter, socket, node.node) {
827 pthread_mutex_lock(socket->lock);
828 ret = consumer_close_trace_chunk(socket,
829 relayd_id,
830 session->id,
831 trace_chunk, closed_trace_chunk_path);
832 pthread_mutex_unlock(socket->lock);
833 if (ret) {
834 ERR("Failed to close trace chunk on kernel consumer");
835 error_occurred = true;
836 }
837 }
838 }
839 ret = error_occurred ? -1 : 0;
840 end:
841 return ret;
842 }
843
844 /*
845 * This function skips the metadata channel as the begin/end timestamps of a
846 * metadata packet are useless.
847 *
848 * Moreover, opening a packet after a "clear" will cause problems for live
849 * sessions as it will introduce padding that was not part of the first trace
850 * chunk. The relay daemon expects the content of the metadata stream of
851 * successive metadata trace chunks to be strict supersets of one another.
852 *
853 * For example, flushing a packet at the beginning of the metadata stream of
854 * a trace chunk resulting from a "clear" session command will cause the
855 * size of the metadata stream of the new trace chunk to not match the size of
856 * the metadata stream of the original chunk. This will confuse the relay
857 * daemon as the same "offset" in a metadata stream will no longer point
858 * to the same content.
859 */
860 static
861 enum lttng_error_code session_kernel_open_packets(struct ltt_session *session)
862 {
863 enum lttng_error_code ret = LTTNG_OK;
864 struct consumer_socket *socket;
865 struct lttng_ht_iter iter;
866 struct cds_lfht_node *node;
867 struct ltt_kernel_channel *chan;
868
869 rcu_read_lock();
870
871 cds_lfht_first(session->kernel_session->consumer->socks->ht, &iter.iter);
872 node = cds_lfht_iter_get_node(&iter.iter);
873 socket = container_of(node, typeof(*socket), node.node);
874
875 cds_list_for_each_entry(chan,
876 &session->kernel_session->channel_list.head, list) {
877 int open_ret;
878
879 DBG("Open packet of kernel channel: channel key = %" PRIu64
880 ", session name = %s, session_id = %" PRIu64,
881 chan->key, session->name, session->id);
882
883 open_ret = consumer_open_channel_packets(socket, chan->key);
884 if (open_ret < 0) {
885 /* General error (no known error expected). */
886 ret = LTTNG_ERR_UNK;
887 goto end;
888 }
889 }
890
891 end:
892 rcu_read_unlock();
893 return ret;
894 }
895
896 enum lttng_error_code session_open_packets(struct ltt_session *session)
897 {
898 enum lttng_error_code ret = LTTNG_OK;
899
900 DBG("Opening packets of session channels: session name = %s, session id = %" PRIu64,
901 session->name, session->id);
902
903 if (session->ust_session) {
904 ret = ust_app_open_packets(session);
905 if (ret != LTTNG_OK) {
906 goto end;
907 }
908 }
909
910 if (session->kernel_session) {
911 ret = session_kernel_open_packets(session);
912 if (ret != LTTNG_OK) {
913 goto end;
914 }
915 }
916
917 end:
918 return ret;
919 }
920
921 /*
922 * Set a session's current trace chunk.
923 *
924 * Must be called with the session lock held.
925 */
926 int session_set_trace_chunk(struct ltt_session *session,
927 struct lttng_trace_chunk *new_trace_chunk,
928 struct lttng_trace_chunk **current_trace_chunk)
929 {
930 ASSERT_LOCKED(session->lock);
931 return _session_set_trace_chunk_no_lock_check(session, new_trace_chunk,
932 current_trace_chunk);
933 }
934
935 static
936 void session_notify_destruction(const struct ltt_session *session)
937 {
938 size_t i;
939 const size_t count = lttng_dynamic_array_get_count(
940 &session->destroy_notifiers);
941
942 for (i = 0; i < count; i++) {
943 const struct ltt_session_destroy_notifier_element *element =
944 (ltt_session_destroy_notifier_element *) lttng_dynamic_array_get_element(
945 &session->destroy_notifiers, i);
946
947 element->notifier(session, element->user_data);
948 }
949 }
950
951 /*
952 * Fire each clear notifier once, and remove them from the array.
953 */
954 void session_notify_clear(struct ltt_session *session)
955 {
956 size_t i;
957 const size_t count = lttng_dynamic_array_get_count(
958 &session->clear_notifiers);
959
960 for (i = 0; i < count; i++) {
961 const struct ltt_session_clear_notifier_element *element =
962 (ltt_session_clear_notifier_element *) lttng_dynamic_array_get_element(
963 &session->clear_notifiers, i);
964
965 element->notifier(session, element->user_data);
966 }
967 lttng_dynamic_array_clear(&session->clear_notifiers);
968 }
969
970 static
971 void session_release(struct urcu_ref *ref)
972 {
973 int ret;
974 struct ltt_ust_session *usess;
975 struct ltt_kernel_session *ksess;
976 struct ltt_session *session = container_of(ref, typeof(*session), ref);
977 const bool session_published = session->published;
978
979 LTTNG_ASSERT(!session->chunk_being_archived);
980
981 usess = session->ust_session;
982 ksess = session->kernel_session;
983
984 /* Clean kernel session teardown, keeping data for destroy notifier. */
985 kernel_destroy_session(ksess);
986
987 /* UST session teardown, keeping data for destroy notifier. */
988 if (usess) {
989 /* Close any relayd session */
990 consumer_output_send_destroy_relayd(usess->consumer);
991
992 /* Destroy every UST application related to this session. */
993 ret = ust_app_destroy_trace_all(usess);
994 if (ret) {
995 ERR("Error in ust_app_destroy_trace_all");
996 }
997
998 /* Clean up the rest, keeping destroy notifier data. */
999 trace_ust_destroy_session(usess);
1000 }
1001
1002 /*
1003 * Must notify the kernel thread here to update it's poll set in order to
1004 * remove the channel(s)' fd just destroyed.
1005 */
1006 ret = notify_thread_pipe(the_kernel_poll_pipe[1]);
1007 if (ret < 0) {
1008 PERROR("write kernel poll pipe");
1009 }
1010
1011 DBG("Destroying session %s (id %" PRIu64 ")", session->name, session->id);
1012
1013 snapshot_destroy(&session->snapshot);
1014
1015 pthread_mutex_destroy(&session->lock);
1016
1017 if (session_published) {
1018 ASSERT_LOCKED(ltt_session_list.lock);
1019 del_session_list(session);
1020 del_session_ht(session);
1021 }
1022 session_notify_destruction(session);
1023
1024 consumer_output_put(session->consumer);
1025 kernel_free_session(ksess);
1026 session->kernel_session = NULL;
1027 if (usess) {
1028 trace_ust_free_session(usess);
1029 session->ust_session = NULL;
1030 }
1031 lttng_dynamic_array_reset(&session->destroy_notifiers);
1032 lttng_dynamic_array_reset(&session->clear_notifiers);
1033 free(session->last_archived_chunk_name);
1034 free(session->base_path);
1035 free(session);
1036 if (session_published) {
1037 /*
1038 * Broadcast after free-ing to ensure the memory is
1039 * reclaimed before the main thread exits.
1040 */
1041 ASSERT_LOCKED(ltt_session_list.lock);
1042 pthread_cond_broadcast(&ltt_session_list.removal_cond);
1043 }
1044 }
1045
1046 /*
1047 * Acquire a reference to a session.
1048 * This function may fail (return false); its return value must be checked.
1049 */
1050 bool session_get(struct ltt_session *session)
1051 {
1052 return urcu_ref_get_unless_zero(&session->ref);
1053 }
1054
1055 /*
1056 * Release a reference to a session.
1057 */
1058 void session_put(struct ltt_session *session)
1059 {
1060 if (!session) {
1061 return;
1062 }
1063 /*
1064 * The session list lock must be held as any session_put()
1065 * may cause the removal of the session from the session_list.
1066 */
1067 ASSERT_LOCKED(ltt_session_list.lock);
1068 LTTNG_ASSERT(session->ref.refcount);
1069 urcu_ref_put(&session->ref, session_release);
1070 }
1071
1072 /*
1073 * Destroy a session.
1074 *
1075 * This method does not immediately release/free the session as other
1076 * components may still hold a reference to the session. However,
1077 * the session should no longer be presented to the user.
1078 *
1079 * Releases the session list's reference to the session
1080 * and marks it as destroyed. Iterations on the session list should be
1081 * mindful of the "destroyed" flag.
1082 */
1083 void session_destroy(struct ltt_session *session)
1084 {
1085 int ret;
1086 struct lttng_ht_iter iter;
1087
1088 LTTNG_ASSERT(!session->destroyed);
1089 session->destroyed = true;
1090
1091 /*
1092 * Remove immediately from the "session by name" hash table. Only one
1093 * session is expected to exist with a given name for at any given time.
1094 *
1095 * Even if a session still technically exists for a little while longer,
1096 * there is no point in performing action on a "destroyed" session.
1097 */
1098 iter.iter.node = &session->node_by_name.node;
1099 ret = lttng_ht_del(ltt_sessions_ht_by_name, &iter);
1100 LTTNG_ASSERT(!ret);
1101
1102 session_put(session);
1103 }
1104
1105 int session_add_destroy_notifier(struct ltt_session *session,
1106 ltt_session_destroy_notifier notifier, void *user_data)
1107 {
1108 const struct ltt_session_destroy_notifier_element element = {
1109 .notifier = notifier,
1110 .user_data = user_data
1111 };
1112
1113 return lttng_dynamic_array_add_element(&session->destroy_notifiers,
1114 &element);
1115 }
1116
1117 int session_add_clear_notifier(struct ltt_session *session,
1118 ltt_session_clear_notifier notifier, void *user_data)
1119 {
1120 const struct ltt_session_clear_notifier_element element = {
1121 .notifier = notifier,
1122 .user_data = user_data
1123 };
1124
1125 return lttng_dynamic_array_add_element(&session->clear_notifiers,
1126 &element);
1127 }
1128
1129 /*
1130 * Return a ltt_session structure ptr that matches name. If no session found,
1131 * NULL is returned. This must be called with the session list lock held using
1132 * session_lock_list and session_unlock_list.
1133 * A reference to the session is implicitly acquired by this function.
1134 */
1135 struct ltt_session *session_find_by_name(const char *name)
1136 {
1137 struct ltt_session *iter;
1138
1139 LTTNG_ASSERT(name);
1140 ASSERT_LOCKED(ltt_session_list.lock);
1141
1142 DBG2("Trying to find session by name %s", name);
1143
1144 cds_list_for_each_entry(iter, &ltt_session_list.head, list) {
1145 if (!strncmp(iter->name, name, NAME_MAX) &&
1146 !iter->destroyed) {
1147 goto found;
1148 }
1149 }
1150
1151 return NULL;
1152 found:
1153 return session_get(iter) ? iter : NULL;
1154 }
1155
1156 /*
1157 * Return an ltt_session that matches the id. If no session is found,
1158 * NULL is returned. This must be called with rcu_read_lock and
1159 * session list lock held (to guarantee the lifetime of the session).
1160 */
1161 struct ltt_session *session_find_by_id(uint64_t id)
1162 {
1163 struct lttng_ht_node_u64 *node;
1164 struct lttng_ht_iter iter;
1165 struct ltt_session *ls;
1166
1167 ASSERT_RCU_READ_LOCKED();
1168 ASSERT_LOCKED(ltt_session_list.lock);
1169
1170 if (!ltt_sessions_ht_by_id) {
1171 goto end;
1172 }
1173
1174 lttng_ht_lookup(ltt_sessions_ht_by_id, &id, &iter);
1175 node = lttng_ht_iter_get_node_u64(&iter);
1176 if (node == NULL) {
1177 goto end;
1178 }
1179 ls = caa_container_of(node, struct ltt_session, node);
1180
1181 DBG3("Session %" PRIu64 " found by id.", id);
1182 return session_get(ls) ? ls : NULL;
1183
1184 end:
1185 DBG3("Session %" PRIu64 " NOT found by id", id);
1186 return NULL;
1187 }
1188
1189 /*
1190 * Create a new session and add it to the session list.
1191 * Session list lock must be held by the caller.
1192 */
1193 enum lttng_error_code session_create(const char *name, uid_t uid, gid_t gid,
1194 struct ltt_session **out_session)
1195 {
1196 int ret;
1197 enum lttng_error_code ret_code;
1198 struct ltt_session *new_session = NULL;
1199
1200 ASSERT_LOCKED(ltt_session_list.lock);
1201 if (name) {
1202 struct ltt_session *clashing_session;
1203
1204 clashing_session = session_find_by_name(name);
1205 if (clashing_session) {
1206 session_put(clashing_session);
1207 ret_code = LTTNG_ERR_EXIST_SESS;
1208 goto error;
1209 }
1210 }
1211 new_session = zmalloc<ltt_session>();
1212 if (!new_session) {
1213 PERROR("Failed to allocate an ltt_session structure");
1214 ret_code = LTTNG_ERR_NOMEM;
1215 goto error;
1216 }
1217
1218 lttng_dynamic_array_init(&new_session->destroy_notifiers,
1219 sizeof(struct ltt_session_destroy_notifier_element),
1220 NULL);
1221 lttng_dynamic_array_init(&new_session->clear_notifiers,
1222 sizeof(struct ltt_session_clear_notifier_element),
1223 NULL);
1224 urcu_ref_init(&new_session->ref);
1225 pthread_mutex_init(&new_session->lock, NULL);
1226
1227 new_session->creation_time = time(NULL);
1228 if (new_session->creation_time == (time_t) -1) {
1229 PERROR("Failed to sample session creation time");
1230 ret_code = LTTNG_ERR_SESSION_FAIL;
1231 goto error;
1232 }
1233
1234 /* Create default consumer output. */
1235 new_session->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
1236 if (new_session->consumer == NULL) {
1237 ret_code = LTTNG_ERR_NOMEM;
1238 goto error;
1239 }
1240
1241 if (name) {
1242 ret = lttng_strncpy(new_session->name, name, sizeof(new_session->name));
1243 if (ret) {
1244 ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
1245 goto error;
1246 }
1247 ret = validate_name(name);
1248 if (ret < 0) {
1249 ret_code = LTTNG_ERR_SESSION_INVALID_CHAR;
1250 goto error;
1251 }
1252 } else {
1253 int i = 0;
1254 bool found_name = false;
1255 char datetime[16];
1256 struct tm *timeinfo;
1257
1258 timeinfo = localtime(&new_session->creation_time);
1259 if (!timeinfo) {
1260 ret_code = LTTNG_ERR_SESSION_FAIL;
1261 goto error;
1262 }
1263 strftime(datetime, sizeof(datetime), "%Y%m%d-%H%M%S", timeinfo);
1264 for (i = 0; i < INT_MAX; i++) {
1265 struct ltt_session *clashing_session;
1266
1267 if (i == 0) {
1268 ret = snprintf(new_session->name,
1269 sizeof(new_session->name),
1270 "%s-%s",
1271 DEFAULT_SESSION_NAME,
1272 datetime);
1273 } else {
1274 ret = snprintf(new_session->name,
1275 sizeof(new_session->name),
1276 "%s%d-%s",
1277 DEFAULT_SESSION_NAME, i,
1278 datetime);
1279 }
1280 new_session->name_contains_creation_time = true;
1281 if (ret == -1 || ret >= sizeof(new_session->name)) {
1282 /*
1283 * Null-terminate in case the name is used
1284 * in logging statements.
1285 */
1286 new_session->name[sizeof(new_session->name) - 1] = '\0';
1287 ret_code = LTTNG_ERR_SESSION_FAIL;
1288 goto error;
1289 }
1290
1291 clashing_session =
1292 session_find_by_name(new_session->name);
1293 session_put(clashing_session);
1294 if (!clashing_session) {
1295 found_name = true;
1296 break;
1297 }
1298 }
1299 if (found_name) {
1300 DBG("Generated session name \"%s\"", new_session->name);
1301 new_session->has_auto_generated_name = true;
1302 } else {
1303 ERR("Failed to auto-generate a session name");
1304 ret_code = LTTNG_ERR_SESSION_FAIL;
1305 goto error;
1306 }
1307 }
1308
1309 ret = gethostname(new_session->hostname, sizeof(new_session->hostname));
1310 if (ret < 0) {
1311 if (errno == ENAMETOOLONG) {
1312 new_session->hostname[sizeof(new_session->hostname) - 1] = '\0';
1313 ERR("Hostname exceeds the maximal permitted length and has been truncated to %s",
1314 new_session->hostname);
1315 } else {
1316 ret_code = LTTNG_ERR_SESSION_FAIL;
1317 goto error;
1318 }
1319 }
1320
1321 new_session->uid = uid;
1322 new_session->gid = gid;
1323
1324 ret = snapshot_init(&new_session->snapshot);
1325 if (ret < 0) {
1326 ret_code = LTTNG_ERR_NOMEM;
1327 goto error;
1328 }
1329
1330 new_session->rotation_state = LTTNG_ROTATION_STATE_NO_ROTATION;
1331
1332 /* Add new session to the session list. */
1333 new_session->id = add_session_list(new_session);
1334
1335 /*
1336 * Add the new session to the ltt_sessions_ht_by_id.
1337 * No ownership is taken by the hash table; it is merely
1338 * a wrapper around the session list used for faster access
1339 * by session id.
1340 */
1341 add_session_ht(new_session);
1342 new_session->published = true;
1343
1344 /*
1345 * Consumer is left to NULL since the create_session_uri command will
1346 * set it up and, if valid, assign it to the session.
1347 */
1348 DBG("Tracing session %s created with ID %" PRIu64 " by uid = %d, gid = %d",
1349 new_session->name, new_session->id, new_session->uid,
1350 new_session->gid);
1351 ret_code = LTTNG_OK;
1352 end:
1353 if (new_session) {
1354 (void) session_get(new_session);
1355 *out_session = new_session;
1356 }
1357 return ret_code;
1358 error:
1359 session_put(new_session);
1360 new_session = NULL;
1361 goto end;
1362 }
1363
1364 /*
1365 * Check if the UID matches the session. Root user has access to all
1366 * sessions.
1367 */
1368 bool session_access_ok(struct ltt_session *session, uid_t uid)
1369 {
1370 LTTNG_ASSERT(session);
1371 return (uid == session->uid) || uid == 0;
1372 }
1373
1374 /*
1375 * Set a session's rotation state and reset all associated state.
1376 *
1377 * This function resets the rotation state (check timers, pending
1378 * flags, etc.) and sets the result of the last rotation. The result
1379 * can be queries by a liblttng-ctl client.
1380 *
1381 * Be careful of the result passed to this function. For instance,
1382 * on failure to launch a rotation, a client will expect the rotation
1383 * state to be set to "NO_ROTATION". If an error occurred while the
1384 * rotation was "ONGOING", result should be set to "ERROR", which will
1385 * allow a client to report it.
1386 *
1387 * Must be called with the session and session_list locks held.
1388 */
1389 int session_reset_rotation_state(struct ltt_session *session,
1390 enum lttng_rotation_state result)
1391 {
1392 int ret = 0;
1393
1394 ASSERT_LOCKED(ltt_session_list.lock);
1395 ASSERT_LOCKED(session->lock);
1396
1397 session->rotation_state = result;
1398 if (session->rotation_pending_check_timer_enabled) {
1399 ret = timer_session_rotation_pending_check_stop(session);
1400 }
1401 if (session->chunk_being_archived) {
1402 uint64_t chunk_id;
1403 enum lttng_trace_chunk_status chunk_status;
1404
1405 chunk_status = lttng_trace_chunk_get_id(
1406 session->chunk_being_archived,
1407 &chunk_id);
1408 LTTNG_ASSERT(chunk_status == LTTNG_TRACE_CHUNK_STATUS_OK);
1409 LTTNG_OPTIONAL_SET(&session->last_archived_chunk_id,
1410 chunk_id);
1411 lttng_trace_chunk_put(session->chunk_being_archived);
1412 session->chunk_being_archived = NULL;
1413 /*
1414 * Fire the clear reply notifiers if we are completing a clear
1415 * rotation.
1416 */
1417 session_notify_clear(session);
1418 }
1419 return ret;
1420 }
1421
1422 /*
1423 * Sample the id of a session looked up via its name.
1424 * Here the term "sampling" hint the caller that this return the id at a given
1425 * point in time with no guarantee that the session for which the id was
1426 * sampled still exist at that point.
1427 *
1428 * Return 0 when the session is not found,
1429 * Return 1 when the session is found and set `id`.
1430 */
1431 bool sample_session_id_by_name(const char *name, uint64_t *id)
1432 {
1433 bool found = false;
1434 struct lttng_ht_node_str *node;
1435 struct lttng_ht_iter iter;
1436 struct ltt_session *ls;
1437
1438 rcu_read_lock();
1439
1440 if (!ltt_sessions_ht_by_name) {
1441 found = false;
1442 goto end;
1443 }
1444
1445 lttng_ht_lookup(ltt_sessions_ht_by_name, name, &iter);
1446 node = lttng_ht_iter_get_node_str(&iter);
1447 if (node == NULL) {
1448 found = false;
1449 goto end;
1450 }
1451
1452 ls = caa_container_of(node, struct ltt_session, node_by_name);
1453 *id = ls->id;
1454 found = true;
1455
1456 DBG3("Session id `%" PRIu64 "` sampled for session `%s", *id, name);
1457 end:
1458 rcu_read_unlock();
1459 return found;
1460 }
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