2 * Copyright (C) 2011 EfficiOS Inc.
4 * SPDX-License-Identifier: GPL-2.0-only
11 #include "lttng-sessiond.hpp"
12 #include "session.hpp"
14 #include "trace-ust.hpp"
17 #include <common/common.hpp>
18 #include <common/sessiond-comm/sessiond-comm.hpp>
19 #include <common/trace-chunk.hpp>
20 #include <common/urcu.hpp>
21 #include <common/utils.hpp>
23 #include <lttng/location-internal.hpp>
33 #include <sys/types.h>
37 struct ltt_session_destroy_notifier_element
{
38 ltt_session_destroy_notifier notifier
;
42 struct ltt_session_clear_notifier_element
{
43 ltt_session_clear_notifier notifier
;
47 namespace ls
= lttng::sessiond
;
52 * No ltt_session.lock is taken here because those data structure are widely
53 * spread across the lttng-tools code base so before calling functions below
54 * that can read/write a session, the caller MUST acquire the session lock
55 * using session_lock() and session_unlock().
58 /* These characters are forbidden in a session name. Used by validate_name. */
59 const char *forbidden_name_chars
= "/";
61 /* Global hash table to keep the sessions, indexed by id. */
62 struct lttng_ht
*ltt_sessions_ht_by_id
= nullptr;
63 /* Global hash table to keep the sessions, indexed by name. */
64 struct lttng_ht
*ltt_sessions_ht_by_name
= nullptr;
67 * Init tracing session list.
69 * Please see session.h for more explanation and correct usage of the list.
71 struct ltt_session_list the_session_list
= {
72 .lock
= PTHREAD_MUTEX_INITIALIZER
,
73 .removal_cond
= PTHREAD_COND_INITIALIZER
,
75 .head
= CDS_LIST_HEAD_INIT(the_session_list
.head
),
80 * Validate the session name for forbidden characters.
82 * Return 0 on success else -1 meaning a forbidden char. has been found.
84 static int validate_name(const char *name
)
91 tmp_name
= strdup(name
);
98 tok
= strpbrk(tmp_name
, forbidden_name_chars
);
100 DBG("Session name %s contains a forbidden character", name
);
101 /* Forbidden character has been found. */
113 * Add a ltt_session structure to the global list.
115 * The caller MUST acquire the session list lock before.
116 * Returns the unique identifier for the session.
118 static uint64_t add_session_list(struct ltt_session
*ls
)
122 cds_list_add(&ls
->list
, &the_session_list
.head
);
123 return the_session_list
.next_uuid
++;
127 * Delete a ltt_session structure to the global list.
129 * The caller MUST acquire the session list lock before.
131 static void del_session_list(struct ltt_session
*ls
)
135 cds_list_del(&ls
->list
);
139 * Return a pointer to the session list.
141 struct ltt_session_list
*session_get_list()
143 return &the_session_list
;
147 * Returns once the session list is empty.
149 void session_list_wait_empty()
151 pthread_mutex_lock(&the_session_list
.lock
);
152 while (!cds_list_empty(&the_session_list
.head
)) {
153 pthread_cond_wait(&the_session_list
.removal_cond
, &the_session_list
.lock
);
155 pthread_mutex_unlock(&the_session_list
.lock
);
159 * Acquire session list lock
161 void session_lock_list()
163 pthread_mutex_lock(&the_session_list
.lock
);
167 * Try to acquire session list lock
169 int session_trylock_list()
171 return pthread_mutex_trylock(&the_session_list
.lock
);
175 * Release session list lock
177 void session_unlock_list()
179 pthread_mutex_unlock(&the_session_list
.lock
);
183 * Get the session's consumer destination type.
185 * The caller must hold the session lock.
187 enum consumer_dst_type
session_get_consumer_destination_type(const struct ltt_session
*session
)
190 * The output information is duplicated in both of those session types.
191 * Hence, it doesn't matter from which it is retrieved. However, it is
192 * possible for only one of them to be set.
194 return session
->kernel_session
? session
->kernel_session
->consumer
->type
:
195 session
->ust_session
->consumer
->type
;
199 * Get the session's consumer network hostname.
200 * The caller must ensure that the destination is of type "net".
202 * The caller must hold the session lock.
204 const char *session_get_net_consumer_hostname(const struct ltt_session
*session
)
206 const char *hostname
= nullptr;
207 const struct consumer_output
*output
;
209 output
= session
->kernel_session
? session
->kernel_session
->consumer
:
210 session
->ust_session
->consumer
;
213 * hostname is assumed to be the same for both control and data
216 switch (output
->dst
.net
.control
.dtype
) {
218 hostname
= output
->dst
.net
.control
.dst
.ipv4
;
221 hostname
= output
->dst
.net
.control
.dst
.ipv6
;
230 * Get the session's consumer network control and data ports.
231 * The caller must ensure that the destination is of type "net".
233 * The caller must hold the session lock.
235 void session_get_net_consumer_ports(const struct ltt_session
*session
,
236 uint16_t *control_port
,
239 const struct consumer_output
*output
;
241 output
= session
->kernel_session
? session
->kernel_session
->consumer
:
242 session
->ust_session
->consumer
;
243 *control_port
= output
->dst
.net
.control
.port
;
244 *data_port
= output
->dst
.net
.data
.port
;
248 * Get the location of the latest trace archive produced by a rotation.
250 * The caller must hold the session lock.
252 struct lttng_trace_archive_location
*
253 session_get_trace_archive_location(const struct ltt_session
*session
)
256 struct lttng_trace_archive_location
*location
= nullptr;
257 char *chunk_path
= nullptr;
259 if (session
->rotation_state
!= LTTNG_ROTATION_STATE_COMPLETED
||
260 !session
->last_archived_chunk_name
) {
264 switch (session_get_consumer_destination_type(session
)) {
265 case CONSUMER_DST_LOCAL
:
266 ret
= asprintf(&chunk_path
,
267 "%s/" DEFAULT_ARCHIVED_TRACE_CHUNKS_DIRECTORY
"/%s",
268 session_get_base_path(session
),
269 session
->last_archived_chunk_name
);
273 location
= lttng_trace_archive_location_local_create(chunk_path
);
275 case CONSUMER_DST_NET
:
277 const char *hostname
;
278 uint16_t control_port
, data_port
;
280 hostname
= session_get_net_consumer_hostname(session
);
281 session_get_net_consumer_ports(session
, &control_port
, &data_port
);
282 location
= lttng_trace_archive_location_relay_create(
284 LTTNG_TRACE_ARCHIVE_LOCATION_RELAY_PROTOCOL_TYPE_TCP
,
287 session
->last_chunk_path
);
299 * Allocate the ltt_sessions_ht_by_id and ltt_sessions_ht_by_name HT.
301 * The session list lock must be held.
303 static int ltt_sessions_ht_alloc()
307 DBG("Allocating ltt_sessions_ht_by_id");
308 ltt_sessions_ht_by_id
= lttng_ht_new(0, LTTNG_HT_TYPE_U64
);
309 if (!ltt_sessions_ht_by_id
) {
311 ERR("Failed to allocate ltt_sessions_ht_by_id");
315 DBG("Allocating ltt_sessions_ht_by_name");
316 ltt_sessions_ht_by_name
= lttng_ht_new(0, LTTNG_HT_TYPE_STRING
);
317 if (!ltt_sessions_ht_by_name
) {
319 ERR("Failed to allocate ltt_sessions_ht_by_name");
328 * Destroy the ltt_sessions_ht_by_id HT.
330 * The session list lock must be held.
332 static void ltt_sessions_ht_destroy()
334 if (ltt_sessions_ht_by_id
) {
335 lttng_ht_destroy(ltt_sessions_ht_by_id
);
336 ltt_sessions_ht_by_id
= nullptr;
339 if (ltt_sessions_ht_by_name
) {
340 lttng_ht_destroy(ltt_sessions_ht_by_name
);
341 ltt_sessions_ht_by_name
= nullptr;
348 * Add a ltt_session to the ltt_sessions_ht_by_id and ltt_sessions_ht_by_name.
349 * If unallocated, the ltt_sessions_ht_by_id and ltt_sessions_ht_by_name. HTs
350 * are allocated. The session list lock must be held.
352 static void add_session_ht(struct ltt_session
*ls
)
358 if (!ltt_sessions_ht_by_id
) {
359 ret
= ltt_sessions_ht_alloc();
361 ERR("Error allocating the sessions HT");
366 /* Should always be present with ltt_sessions_ht_by_id. */
367 LTTNG_ASSERT(ltt_sessions_ht_by_name
);
369 lttng_ht_node_init_u64(&ls
->node
, ls
->id
);
370 lttng_ht_add_unique_u64(ltt_sessions_ht_by_id
, &ls
->node
);
372 lttng_ht_node_init_str(&ls
->node_by_name
, ls
->name
);
373 lttng_ht_add_unique_str(ltt_sessions_ht_by_name
, &ls
->node_by_name
);
380 * Test if ltt_sessions_ht_by_id/name are empty.
381 * Return `false` if hash table objects are null.
382 * The session list lock must be held.
384 static bool ltt_sessions_ht_empty()
388 if (!ltt_sessions_ht_by_id
) {
389 /* The hash tables do not exist yet. */
393 LTTNG_ASSERT(ltt_sessions_ht_by_name
);
395 if (lttng_ht_get_count(ltt_sessions_ht_by_id
) != 0) {
401 * At this point it is expected that the `ltt_sessions_ht_by_name` ht is
404 * The removal from both hash tables is done in two different
406 * - removal from `ltt_sessions_ht_by_name` is done during
407 * `session_destroy()`
408 * - removal from `ltt_sessions_ht_by_id` is done later
409 * in `session_release()` on the last reference put.
411 * This means that it is possible for `ltt_sessions_ht_by_name` to be
412 * empty but for `ltt_sessions_ht_by_id` to still contain objects when
413 * multiple sessions exists. The reverse is false, hence this sanity
416 LTTNG_ASSERT(lttng_ht_get_count(ltt_sessions_ht_by_name
) == 0);
423 * Remove a ltt_session from the ltt_sessions_ht_by_id.
424 * If empty, the ltt_sessions_ht_by_id/name HTs are freed.
425 * The session list lock must be held.
427 static void del_session_ht(struct ltt_session
*ls
)
429 struct lttng_ht_iter iter
;
433 LTTNG_ASSERT(ltt_sessions_ht_by_id
);
434 LTTNG_ASSERT(ltt_sessions_ht_by_name
);
436 iter
.iter
.node
= &ls
->node
.node
;
437 ret
= lttng_ht_del(ltt_sessions_ht_by_id
, &iter
);
440 if (ltt_sessions_ht_empty()) {
441 DBG("Empty ltt_sessions_ht_by_id/name, destroying hast tables");
442 ltt_sessions_ht_destroy();
447 * Acquire session lock
449 void session_lock(struct ltt_session
*session
)
451 LTTNG_ASSERT(session
);
453 pthread_mutex_lock(&session
->lock
);
457 * Release session lock
459 void session_unlock(struct ltt_session
*session
)
461 LTTNG_ASSERT(session
);
463 pthread_mutex_unlock(&session
->lock
);
466 static 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
)
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
;
476 enum lttng_trace_chunk_status chunk_status
;
480 * Ownership of current trace chunk is transferred to
481 * `current_trace_chunk`.
483 current_trace_chunk
= session
->current_trace_chunk
;
484 session
->current_trace_chunk
= nullptr;
485 if (session
->ust_session
) {
486 lttng_trace_chunk_put(session
->ust_session
->current_trace_chunk
);
487 session
->ust_session
->current_trace_chunk
= nullptr;
489 if (session
->kernel_session
) {
490 lttng_trace_chunk_put(session
->kernel_session
->current_trace_chunk
);
491 session
->kernel_session
->current_trace_chunk
= nullptr;
493 if (!new_trace_chunk
) {
497 chunk_status
= lttng_trace_chunk_get_id(new_trace_chunk
, &chunk_id
);
498 LTTNG_ASSERT(chunk_status
== LTTNG_TRACE_CHUNK_STATUS_OK
);
501 refs_to_acquire
+= !!session
->ust_session
;
502 refs_to_acquire
+= !!session
->kernel_session
;
504 for (refs_acquired
= 0; refs_acquired
< refs_to_acquire
; refs_acquired
++) {
505 if (!lttng_trace_chunk_get(new_trace_chunk
)) {
506 ERR("Failed to acquire reference to new trace chunk of session \"%s\"",
512 if (session
->ust_session
) {
513 const uint64_t relayd_id
= session
->ust_session
->consumer
->net_seq_index
;
514 const bool is_local_trace
= session
->ust_session
->consumer
->type
==
517 session
->ust_session
->current_trace_chunk
= new_trace_chunk
;
518 if (is_local_trace
) {
519 enum lttng_error_code ret_error_code
;
522 ust_app_create_channel_subdirectories(session
->ust_session
);
523 if (ret_error_code
!= LTTNG_OK
) {
527 cds_lfht_for_each_entry (
528 session
->ust_session
->consumer
->socks
->ht
, &iter
, socket
, node
.node
) {
529 pthread_mutex_lock(socket
->lock
);
530 ret
= consumer_create_trace_chunk(socket
,
534 DEFAULT_UST_TRACE_DIR
);
535 pthread_mutex_unlock(socket
->lock
);
541 if (session
->kernel_session
) {
542 const uint64_t relayd_id
= session
->kernel_session
->consumer
->net_seq_index
;
543 const bool is_local_trace
= session
->kernel_session
->consumer
->type
==
546 session
->kernel_session
->current_trace_chunk
= new_trace_chunk
;
547 if (is_local_trace
) {
548 enum lttng_error_code ret_error_code
;
551 kernel_create_channel_subdirectories(session
->kernel_session
);
552 if (ret_error_code
!= LTTNG_OK
) {
556 cds_lfht_for_each_entry (
557 session
->kernel_session
->consumer
->socks
->ht
, &iter
, socket
, node
.node
) {
558 pthread_mutex_lock(socket
->lock
);
559 ret
= consumer_create_trace_chunk(socket
,
563 DEFAULT_KERNEL_TRACE_DIR
);
564 pthread_mutex_unlock(socket
->lock
);
572 * Update local current trace chunk state last, only if all remote
573 * creations succeeded.
575 session
->current_trace_chunk
= new_trace_chunk
;
576 LTTNG_OPTIONAL_SET(&session
->most_recent_chunk_id
, chunk_id
);
578 if (_current_trace_chunk
) {
579 *_current_trace_chunk
= current_trace_chunk
;
580 current_trace_chunk
= nullptr;
584 lttng_trace_chunk_put(current_trace_chunk
);
587 if (session
->ust_session
) {
588 session
->ust_session
->current_trace_chunk
= nullptr;
590 if (session
->kernel_session
) {
591 session
->kernel_session
->current_trace_chunk
= nullptr;
594 * Release references taken in the case where all references could not
597 refs_to_release
= refs_to_acquire
- refs_acquired
;
598 for (i
= 0; i
< refs_to_release
; i
++) {
599 lttng_trace_chunk_put(new_trace_chunk
);
605 struct lttng_trace_chunk
*
606 session_create_new_trace_chunk(const struct ltt_session
*session
,
607 const struct consumer_output
*consumer_output_override
,
608 const char *session_base_path_override
,
609 const char *chunk_name_override
)
612 struct lttng_trace_chunk
*trace_chunk
= nullptr;
613 enum lttng_trace_chunk_status chunk_status
;
614 const time_t chunk_creation_ts
= time(nullptr);
616 const char *base_path
;
617 struct lttng_directory_handle
*session_output_directory
= nullptr;
618 const struct lttng_credentials session_credentials
= {
619 .uid
= LTTNG_OPTIONAL_INIT_VALUE(session
->uid
),
620 .gid
= LTTNG_OPTIONAL_INIT_VALUE(session
->gid
),
622 uint64_t next_chunk_id
;
623 const struct consumer_output
*output
;
624 const char *new_path
;
626 if (consumer_output_override
) {
627 output
= consumer_output_override
;
629 LTTNG_ASSERT(session
->ust_session
|| session
->kernel_session
);
630 output
= session
->ust_session
? session
->ust_session
->consumer
:
631 session
->kernel_session
->consumer
;
634 is_local_trace
= output
->type
== CONSUMER_DST_LOCAL
;
635 base_path
= session_base_path_override
?: consumer_output_get_base_path(output
);
637 if (chunk_creation_ts
== (time_t) -1) {
638 PERROR("Failed to sample time while creation session \"%s\" trace chunk",
644 session
->most_recent_chunk_id
.is_set
? session
->most_recent_chunk_id
.value
+ 1 : 0;
646 if (session
->current_trace_chunk
&&
647 !lttng_trace_chunk_get_name_overridden(session
->current_trace_chunk
)) {
648 chunk_status
= lttng_trace_chunk_rename_path(session
->current_trace_chunk
,
649 DEFAULT_CHUNK_TMP_OLD_DIRECTORY
);
650 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
654 if (!session
->current_trace_chunk
) {
655 if (!session
->rotated
) {
661 new_path
= DEFAULT_CHUNK_TMP_NEW_DIRECTORY
;
664 trace_chunk
= lttng_trace_chunk_create(next_chunk_id
, chunk_creation_ts
, new_path
);
669 if (chunk_name_override
) {
670 chunk_status
= lttng_trace_chunk_override_name(trace_chunk
, chunk_name_override
);
671 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
676 if (!is_local_trace
) {
678 * No need to set crendentials and output directory
679 * for remote trace chunks.
684 chunk_status
= lttng_trace_chunk_set_credentials(trace_chunk
, &session_credentials
);
685 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
689 DBG("Creating base output directory of session \"%s\" at %s", session
->name
, base_path
);
690 ret
= utils_mkdir_recursive(base_path
, S_IRWXU
| S_IRWXG
, session
->uid
, session
->gid
);
694 session_output_directory
= lttng_directory_handle_create(base_path
);
695 if (!session_output_directory
) {
698 chunk_status
= lttng_trace_chunk_set_as_owner(trace_chunk
, session_output_directory
);
699 lttng_directory_handle_put(session_output_directory
);
700 session_output_directory
= nullptr;
701 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
707 lttng_directory_handle_put(session_output_directory
);
708 lttng_trace_chunk_put(trace_chunk
);
709 trace_chunk
= nullptr;
713 int session_close_trace_chunk(struct ltt_session
*session
,
714 struct lttng_trace_chunk
*trace_chunk
,
715 enum lttng_trace_chunk_command_type close_command
,
716 char *closed_trace_chunk_path
)
719 bool error_occurred
= false;
720 struct cds_lfht_iter iter
;
721 struct consumer_socket
*socket
;
722 enum lttng_trace_chunk_status chunk_status
;
723 const time_t chunk_close_timestamp
= time(nullptr);
724 const char *new_path
;
726 chunk_status
= lttng_trace_chunk_set_close_command(trace_chunk
, close_command
);
727 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
732 if (chunk_close_timestamp
== (time_t) -1) {
733 ERR("Failed to sample the close timestamp of the current trace chunk of session \"%s\"",
739 if (close_command
== LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE
&& !session
->rotated
) {
740 /* New chunk stays in session output directory. */
743 /* Use chunk name for new chunk. */
746 if (session
->current_trace_chunk
&&
747 !lttng_trace_chunk_get_name_overridden(session
->current_trace_chunk
)) {
748 /* Rename new chunk path. */
750 lttng_trace_chunk_rename_path(session
->current_trace_chunk
, new_path
);
751 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
756 if (!lttng_trace_chunk_get_name_overridden(trace_chunk
) &&
757 close_command
== LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION
) {
758 const char *old_path
;
760 if (!session
->rotated
) {
765 /* We need to move back the .tmp_old_chunk to its rightful place. */
766 chunk_status
= lttng_trace_chunk_rename_path(trace_chunk
, old_path
);
767 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
772 if (close_command
== LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED
) {
773 session
->rotated
= true;
775 chunk_status
= lttng_trace_chunk_set_close_timestamp(trace_chunk
, chunk_close_timestamp
);
776 if (chunk_status
!= LTTNG_TRACE_CHUNK_STATUS_OK
) {
777 ERR("Failed to set the close timestamp of the current trace chunk of session \"%s\"",
783 if (session
->ust_session
) {
784 const uint64_t relayd_id
= session
->ust_session
->consumer
->net_seq_index
;
786 cds_lfht_for_each_entry (
787 session
->ust_session
->consumer
->socks
->ht
, &iter
, socket
, node
.node
) {
788 pthread_mutex_lock(socket
->lock
);
789 ret
= consumer_close_trace_chunk(socket
,
793 closed_trace_chunk_path
);
794 pthread_mutex_unlock(socket
->lock
);
796 ERR("Failed to close trace chunk on user space consumer");
797 error_occurred
= true;
801 if (session
->kernel_session
) {
802 const uint64_t relayd_id
= session
->kernel_session
->consumer
->net_seq_index
;
804 cds_lfht_for_each_entry (
805 session
->kernel_session
->consumer
->socks
->ht
, &iter
, socket
, node
.node
) {
806 pthread_mutex_lock(socket
->lock
);
807 ret
= consumer_close_trace_chunk(socket
,
811 closed_trace_chunk_path
);
812 pthread_mutex_unlock(socket
->lock
);
814 ERR("Failed to close trace chunk on kernel consumer");
815 error_occurred
= true;
819 ret
= error_occurred
? -1 : 0;
825 * This function skips the metadata channel as the begin/end timestamps of a
826 * metadata packet are useless.
828 * Moreover, opening a packet after a "clear" will cause problems for live
829 * sessions as it will introduce padding that was not part of the first trace
830 * chunk. The relay daemon expects the content of the metadata stream of
831 * successive metadata trace chunks to be strict supersets of one another.
833 * For example, flushing a packet at the beginning of the metadata stream of
834 * a trace chunk resulting from a "clear" session command will cause the
835 * size of the metadata stream of the new trace chunk to not match the size of
836 * the metadata stream of the original chunk. This will confuse the relay
837 * daemon as the same "offset" in a metadata stream will no longer point
838 * to the same content.
840 static enum lttng_error_code
session_kernel_open_packets(struct ltt_session
*session
)
842 enum lttng_error_code ret
= LTTNG_OK
;
843 struct consumer_socket
*socket
;
844 struct lttng_ht_iter iter
;
845 struct cds_lfht_node
*node
;
846 struct ltt_kernel_channel
*chan
;
850 cds_lfht_first(session
->kernel_session
->consumer
->socks
->ht
, &iter
.iter
);
851 node
= cds_lfht_iter_get_node(&iter
.iter
);
852 socket
= caa_container_of(node
, typeof(*socket
), node
.node
);
854 cds_list_for_each_entry (chan
, &session
->kernel_session
->channel_list
.head
, list
) {
857 DBG("Open packet of kernel channel: channel key = %" PRIu64
858 ", session name = %s, session_id = %" PRIu64
,
863 open_ret
= consumer_open_channel_packets(socket
, chan
->key
);
865 /* General error (no known error expected). */
876 enum lttng_error_code
session_open_packets(struct ltt_session
*session
)
878 enum lttng_error_code ret
= LTTNG_OK
;
880 DBG("Opening packets of session channels: session name = %s, session id = %" PRIu64
,
884 if (session
->ust_session
) {
885 ret
= ust_app_open_packets(session
);
886 if (ret
!= LTTNG_OK
) {
891 if (session
->kernel_session
) {
892 ret
= session_kernel_open_packets(session
);
893 if (ret
!= LTTNG_OK
) {
903 * Set a session's current trace chunk.
905 * Must be called with the session lock held.
907 int session_set_trace_chunk(struct ltt_session
*session
,
908 struct lttng_trace_chunk
*new_trace_chunk
,
909 struct lttng_trace_chunk
**current_trace_chunk
)
911 ASSERT_LOCKED(session
->lock
);
912 return _session_set_trace_chunk_no_lock_check(
913 session
, new_trace_chunk
, current_trace_chunk
);
916 static void session_notify_destruction(const struct ltt_session
*session
)
919 const size_t count
= lttng_dynamic_array_get_count(&session
->destroy_notifiers
);
921 for (i
= 0; i
< count
; i
++) {
922 const struct ltt_session_destroy_notifier_element
*element
=
923 (ltt_session_destroy_notifier_element
*) lttng_dynamic_array_get_element(
924 &session
->destroy_notifiers
, i
);
926 element
->notifier(session
, element
->user_data
);
931 * Fire each clear notifier once, and remove them from the array.
933 void session_notify_clear(struct ltt_session
*session
)
936 const size_t count
= lttng_dynamic_array_get_count(&session
->clear_notifiers
);
938 for (i
= 0; i
< count
; i
++) {
939 const struct ltt_session_clear_notifier_element
*element
=
940 (ltt_session_clear_notifier_element
*) lttng_dynamic_array_get_element(
941 &session
->clear_notifiers
, i
);
943 element
->notifier(session
, element
->user_data
);
945 lttng_dynamic_array_clear(&session
->clear_notifiers
);
948 static void session_release(struct urcu_ref
*ref
)
951 struct ltt_ust_session
*usess
;
952 struct ltt_kernel_session
*ksess
;
953 struct ltt_session
*session
= lttng::utils::container_of(ref
, <t_session::ref
);
954 const bool session_published
= session
->published
;
956 LTTNG_ASSERT(!session
->chunk_being_archived
);
958 usess
= session
->ust_session
;
959 ksess
= session
->kernel_session
;
961 /* Clean kernel session teardown, keeping data for destroy notifier. */
962 kernel_destroy_session(ksess
);
964 /* UST session teardown, keeping data for destroy notifier. */
966 /* Close any relayd session */
967 consumer_output_send_destroy_relayd(usess
->consumer
);
969 /* Destroy every UST application related to this session. */
970 ret
= ust_app_destroy_trace_all(usess
);
972 ERR("Error in ust_app_destroy_trace_all");
975 /* Clean up the rest, keeping destroy notifier data. */
976 trace_ust_destroy_session(usess
);
980 * Must notify the kernel thread here to update it's poll set in order to
981 * remove the channel(s)' fd just destroyed.
983 ret
= notify_thread_pipe(the_kernel_poll_pipe
[1]);
985 PERROR("write kernel poll pipe");
988 DBG("Destroying session %s (id %" PRIu64
")", session
->name
, session
->id
);
990 snapshot_destroy(&session
->snapshot
);
992 pthread_mutex_destroy(&session
->lock
);
994 if (session_published
) {
995 ASSERT_LOCKED(the_session_list
.lock
);
996 del_session_list(session
);
997 del_session_ht(session
);
999 session_notify_destruction(session
);
1001 consumer_output_put(session
->consumer
);
1002 kernel_free_session(ksess
);
1003 session
->kernel_session
= nullptr;
1005 trace_ust_free_session(usess
);
1006 session
->ust_session
= nullptr;
1008 lttng_dynamic_array_reset(&session
->destroy_notifiers
);
1009 lttng_dynamic_array_reset(&session
->clear_notifiers
);
1010 free(session
->last_archived_chunk_name
);
1011 free(session
->base_path
);
1012 lttng_trigger_put(session
->rotate_trigger
);
1014 if (session_published
) {
1016 * Broadcast after free-ing to ensure the memory is
1017 * reclaimed before the main thread exits.
1019 ASSERT_LOCKED(the_session_list
.lock
);
1020 pthread_cond_broadcast(&the_session_list
.removal_cond
);
1025 * Acquire a reference to a session.
1026 * This function may fail (return false); its return value must be checked.
1028 bool session_get(struct ltt_session
*session
)
1030 return urcu_ref_get_unless_zero(&session
->ref
);
1034 * Release a reference to a session.
1036 void session_put(struct ltt_session
*session
)
1042 * The session list lock must be held as any session_put()
1043 * may cause the removal of the session from the session_list.
1045 ASSERT_LOCKED(the_session_list
.lock
);
1046 LTTNG_ASSERT(session
->ref
.refcount
);
1047 urcu_ref_put(&session
->ref
, session_release
);
1051 * Destroy a session.
1053 * This method does not immediately release/free the session as other
1054 * components may still hold a reference to the session. However,
1055 * the session should no longer be presented to the user.
1057 * Releases the session list's reference to the session
1058 * and marks it as destroyed. Iterations on the session list should be
1059 * mindful of the "destroyed" flag.
1061 void session_destroy(struct ltt_session
*session
)
1064 struct lttng_ht_iter iter
;
1066 LTTNG_ASSERT(!session
->destroyed
);
1067 session
->destroyed
= true;
1070 * Remove immediately from the "session by name" hash table. Only one
1071 * session is expected to exist with a given name for at any given time.
1073 * Even if a session still technically exists for a little while longer,
1074 * there is no point in performing action on a "destroyed" session.
1076 iter
.iter
.node
= &session
->node_by_name
.node
;
1077 ret
= lttng_ht_del(ltt_sessions_ht_by_name
, &iter
);
1080 session_put(session
);
1083 int session_add_destroy_notifier(struct ltt_session
*session
,
1084 ltt_session_destroy_notifier notifier
,
1087 const struct ltt_session_destroy_notifier_element element
= { .notifier
= notifier
,
1088 .user_data
= user_data
};
1090 return lttng_dynamic_array_add_element(&session
->destroy_notifiers
, &element
);
1093 int session_add_clear_notifier(struct ltt_session
*session
,
1094 ltt_session_clear_notifier notifier
,
1097 const struct ltt_session_clear_notifier_element element
= { .notifier
= notifier
,
1098 .user_data
= user_data
};
1100 return lttng_dynamic_array_add_element(&session
->clear_notifiers
, &element
);
1104 * Return a ltt_session structure ptr that matches name. If no session found,
1105 * NULL is returned. This must be called with the session list lock held using
1106 * session_lock_list and session_unlock_list.
1107 * A reference to the session is implicitly acquired by this function.
1109 struct ltt_session
*session_find_by_name(const char *name
)
1111 struct ltt_session
*iter
;
1114 ASSERT_LOCKED(the_session_list
.lock
);
1116 DBG2("Trying to find session by name %s", name
);
1118 cds_list_for_each_entry (iter
, &the_session_list
.head
, list
) {
1119 if (!strncmp(iter
->name
, name
, NAME_MAX
) && !iter
->destroyed
) {
1126 return session_get(iter
) ? iter
: nullptr;
1130 * Return an ltt_session that matches the id. If no session is found,
1131 * NULL is returned. This must be called with rcu_read_lock and
1132 * session list lock held (to guarantee the lifetime of the session).
1134 struct ltt_session
*session_find_by_id(uint64_t id
)
1136 struct lttng_ht_node_u64
*node
;
1137 struct lttng_ht_iter iter
;
1138 struct ltt_session
*ls
;
1140 ASSERT_RCU_READ_LOCKED();
1141 ASSERT_LOCKED(the_session_list
.lock
);
1143 if (!ltt_sessions_ht_by_id
) {
1147 lttng_ht_lookup(ltt_sessions_ht_by_id
, &id
, &iter
);
1148 node
= lttng_ht_iter_get_node_u64(&iter
);
1149 if (node
== nullptr) {
1152 ls
= lttng::utils::container_of(node
, <t_session::node
);
1154 DBG3("Session %" PRIu64
" found by id.", id
);
1155 return session_get(ls
) ? ls
: nullptr;
1158 DBG3("Session %" PRIu64
" NOT found by id", id
);
1163 * Create a new session and add it to the session list.
1164 * Session list lock must be held by the caller.
1166 enum lttng_error_code
1167 session_create(const char *name
, uid_t uid
, gid_t gid
, struct ltt_session
**out_session
)
1170 enum lttng_error_code ret_code
;
1171 struct ltt_session
*new_session
= nullptr;
1173 ASSERT_LOCKED(the_session_list
.lock
);
1175 struct ltt_session
*clashing_session
;
1177 clashing_session
= session_find_by_name(name
);
1178 if (clashing_session
) {
1179 session_put(clashing_session
);
1180 ret_code
= LTTNG_ERR_EXIST_SESS
;
1184 new_session
= zmalloc
<ltt_session
>();
1186 PERROR("Failed to allocate an ltt_session structure");
1187 ret_code
= LTTNG_ERR_NOMEM
;
1191 lttng_dynamic_array_init(&new_session
->destroy_notifiers
,
1192 sizeof(struct ltt_session_destroy_notifier_element
),
1194 lttng_dynamic_array_init(&new_session
->clear_notifiers
,
1195 sizeof(struct ltt_session_clear_notifier_element
),
1197 urcu_ref_init(&new_session
->ref
);
1198 pthread_mutex_init(&new_session
->lock
, nullptr);
1200 new_session
->creation_time
= time(nullptr);
1201 if (new_session
->creation_time
== (time_t) -1) {
1202 PERROR("Failed to sample session creation time");
1203 ret_code
= LTTNG_ERR_SESSION_FAIL
;
1207 /* Create default consumer output. */
1208 new_session
->consumer
= consumer_create_output(CONSUMER_DST_LOCAL
);
1209 if (new_session
->consumer
== nullptr) {
1210 ret_code
= LTTNG_ERR_NOMEM
;
1215 ret
= lttng_strncpy(new_session
->name
, name
, sizeof(new_session
->name
));
1217 ret_code
= LTTNG_ERR_SESSION_INVALID_CHAR
;
1220 ret
= validate_name(name
);
1222 ret_code
= LTTNG_ERR_SESSION_INVALID_CHAR
;
1227 bool found_name
= false;
1229 struct tm
*timeinfo
;
1231 timeinfo
= localtime(&new_session
->creation_time
);
1233 ret_code
= LTTNG_ERR_SESSION_FAIL
;
1236 strftime(datetime
, sizeof(datetime
), "%Y%m%d-%H%M%S", timeinfo
);
1237 for (i
= 0; i
< INT_MAX
; i
++) {
1238 struct ltt_session
*clashing_session
;
1241 ret
= snprintf(new_session
->name
,
1242 sizeof(new_session
->name
),
1244 DEFAULT_SESSION_NAME
,
1247 ret
= snprintf(new_session
->name
,
1248 sizeof(new_session
->name
),
1250 DEFAULT_SESSION_NAME
,
1254 new_session
->name_contains_creation_time
= true;
1255 if (ret
== -1 || ret
>= sizeof(new_session
->name
)) {
1257 * Null-terminate in case the name is used
1258 * in logging statements.
1260 new_session
->name
[sizeof(new_session
->name
) - 1] = '\0';
1261 ret_code
= LTTNG_ERR_SESSION_FAIL
;
1265 clashing_session
= session_find_by_name(new_session
->name
);
1266 session_put(clashing_session
);
1267 if (!clashing_session
) {
1273 DBG("Generated session name \"%s\"", new_session
->name
);
1274 new_session
->has_auto_generated_name
= true;
1276 ERR("Failed to auto-generate a session name");
1277 ret_code
= LTTNG_ERR_SESSION_FAIL
;
1282 ret
= gethostname(new_session
->hostname
, sizeof(new_session
->hostname
));
1284 if (errno
== ENAMETOOLONG
) {
1285 new_session
->hostname
[sizeof(new_session
->hostname
) - 1] = '\0';
1286 ERR("Hostname exceeds the maximal permitted length and has been truncated to %s",
1287 new_session
->hostname
);
1289 ret_code
= LTTNG_ERR_SESSION_FAIL
;
1294 new_session
->uid
= uid
;
1295 new_session
->gid
= gid
;
1297 ret
= snapshot_init(&new_session
->snapshot
);
1299 ret_code
= LTTNG_ERR_NOMEM
;
1303 new_session
->rotation_state
= LTTNG_ROTATION_STATE_NO_ROTATION
;
1305 /* Add new session to the session list. */
1306 new_session
->id
= add_session_list(new_session
);
1309 * Add the new session to the ltt_sessions_ht_by_id.
1310 * No ownership is taken by the hash table; it is merely
1311 * a wrapper around the session list used for faster access
1314 add_session_ht(new_session
);
1315 new_session
->published
= true;
1318 * Consumer is left to NULL since the create_session_uri command will
1319 * set it up and, if valid, assign it to the session.
1321 DBG("Tracing session %s created with ID %" PRIu64
" by uid = %d, gid = %d",
1326 ret_code
= LTTNG_OK
;
1329 (void) session_get(new_session
);
1330 *out_session
= new_session
;
1334 session_put(new_session
);
1335 new_session
= nullptr;
1340 * Check if the UID matches the session. Root user has access to all
1343 bool session_access_ok(struct ltt_session
*session
, uid_t uid
)
1345 LTTNG_ASSERT(session
);
1346 return (uid
== session
->uid
) || uid
== 0;
1350 * Set a session's rotation state and reset all associated state.
1352 * This function resets the rotation state (check timers, pending
1353 * flags, etc.) and sets the result of the last rotation. The result
1354 * can be queries by a liblttng-ctl client.
1356 * Be careful of the result passed to this function. For instance,
1357 * on failure to launch a rotation, a client will expect the rotation
1358 * state to be set to "NO_ROTATION". If an error occurred while the
1359 * rotation was "ONGOING", result should be set to "ERROR", which will
1360 * allow a client to report it.
1362 * Must be called with the session and session_list locks held.
1364 int session_reset_rotation_state(struct ltt_session
*session
, enum lttng_rotation_state result
)
1368 ASSERT_LOCKED(the_session_list
.lock
);
1369 ASSERT_LOCKED(session
->lock
);
1371 session
->rotation_state
= result
;
1372 if (session
->rotation_pending_check_timer_enabled
) {
1373 ret
= timer_session_rotation_pending_check_stop(session
);
1375 if (session
->chunk_being_archived
) {
1377 enum lttng_trace_chunk_status chunk_status
;
1379 chunk_status
= lttng_trace_chunk_get_id(session
->chunk_being_archived
, &chunk_id
);
1380 LTTNG_ASSERT(chunk_status
== LTTNG_TRACE_CHUNK_STATUS_OK
);
1381 LTTNG_OPTIONAL_SET(&session
->last_archived_chunk_id
, chunk_id
);
1382 lttng_trace_chunk_put(session
->chunk_being_archived
);
1383 session
->chunk_being_archived
= nullptr;
1385 * Fire the clear reply notifiers if we are completing a clear
1388 session_notify_clear(session
);
1394 * Sample the id of a session looked up via its name.
1395 * Here the term "sampling" hint the caller that this return the id at a given
1396 * point in time with no guarantee that the session for which the id was
1397 * sampled still exist at that point.
1399 * Return 0 when the session is not found,
1400 * Return 1 when the session is found and set `id`.
1402 bool sample_session_id_by_name(const char *name
, uint64_t *id
)
1405 struct lttng_ht_node_str
*node
;
1406 struct lttng_ht_iter iter
;
1407 struct ltt_session
*ls
;
1411 if (!ltt_sessions_ht_by_name
) {
1416 lttng_ht_lookup(ltt_sessions_ht_by_name
, name
, &iter
);
1417 node
= lttng_ht_iter_get_node_str(&iter
);
1418 if (node
== nullptr) {
1423 ls
= lttng::utils::container_of(node
, <t_session::node_by_name
);
1427 DBG3("Session id `%" PRIu64
"` sampled for session `%s", *id
, name
);
1433 void ls::details::locked_session_release(ltt_session
*session
)
1435 session_unlock(session
);
1436 session_put(session
);
1439 ltt_session::locked_ptr
ls::find_locked_session_by_id(ltt_session::id_t id
)
1441 lttng::urcu::read_lock_guard rcu_lock
;
1442 auto session
= session_find_by_id(id
);
1449 * The pointer falling out of scope will unlock and release the reference to the
1452 session_lock(session
);
1453 return ltt_session::locked_ptr(session
);
1456 ltt_session::sptr
ls::find_session_by_id(ltt_session::id_t id
)
1458 lttng::urcu::read_lock_guard rcu_lock
;
1459 auto session
= session_find_by_id(id
);
1465 return { session
, session_put
};