2 * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
8 #include "action-executor.h"
10 #include "health-sessiond.h"
11 #include "lttng-sessiond.h"
12 #include "notification-thread-internal.h"
15 #include <common/dynamic-array.h>
16 #include <common/macros.h>
17 #include <common/optional.h>
18 #include <lttng/action/action-internal.h>
19 #include <lttng/action/list-internal.h>
20 #include <lttng/action/list.h>
21 #include <lttng/action/notify-internal.h>
22 #include <lttng/action/notify.h>
23 #include <lttng/action/rotate-session.h>
24 #include <lttng/action/snapshot-session.h>
25 #include <lttng/action/start-session.h>
26 #include <lttng/action/stop-session.h>
27 #include <lttng/condition/evaluation.h>
28 #include <lttng/condition/event-rule-matches-internal.h>
29 #include <lttng/lttng-error.h>
30 #include <lttng/trigger/trigger-internal.h>
34 #include <urcu/list.h>
36 #define THREAD_NAME "Action Executor"
37 #define MAX_QUEUED_WORK_COUNT 8192
40 * A work item is composed of a dynamic array of sub-items which
41 * represent a flattened, and augmented, version of a trigger's actions.
43 * We cannot rely solely on the trigger's actions since each action can have an
44 * execution context we need to comply with.
46 * The notion of execution context is required since for some actions the
47 * associated object are referenced by name and not by id. This can lead to
48 * a number of ambiguities when executing an action work item.
50 * For example, let's take a simple trigger such as:
51 * - condition: ust event a
52 * - action: start session S
54 * At time T, session S exists.
55 * At T + 1, the event A is hit.
56 * At T + 2, the tracer event notification is received and the work item is
57 * queued. Here session S have an id of 1.
58 * At T + 3, the session S is destroyed and a new session S is created, with a
59 * resulting id of 200.
60 * At T +4, the work item is popped from the queue and begin execution and will
61 * start session S with an id of 200 instead of the session S id 1 that was
62 * present at the queuing phase.
64 * The context to be respected is the one when the work item is queued. If the
65 * execution context is not the same at the moment of execution, we skip the
66 * execution of that sub-item.
68 * It is the same policy in regards to the validity of the associated
69 * trigger object at the moment of execution, if the trigger is found to be
70 * unregistered, the execution is skipped.
73 struct action_work_item
{
77 * The actions to be executed with their respective execution context.
78 * See struct `action_work_subitem`.
80 struct lttng_dynamic_array subitems
;
82 /* Execution context data */
83 struct lttng_trigger
*trigger
;
84 struct lttng_evaluation
*evaluation
;
85 struct notification_client_list
*client_list
;
86 LTTNG_OPTIONAL(struct lttng_credentials
) object_creds
;
87 struct cds_list_head list_node
;
90 struct action_work_subitem
{
91 struct lttng_action
*action
;
93 /* Used by actions targeting a session. */
94 LTTNG_OPTIONAL(uint64_t) session_id
;
98 struct action_executor
{
99 struct lttng_thread
*thread
;
100 struct notification_thread_handle
*notification_thread_handle
;
102 uint64_t pending_count
;
103 struct cds_list_head list
;
105 pthread_mutex_t lock
;
108 uint64_t next_work_item_id
;
112 * Only return non-zero on a fatal error that should shut down the action
115 typedef int (*action_executor_handler
)(struct action_executor
*executor
,
116 const struct action_work_item
*,
117 struct action_work_subitem
*item
);
119 static int action_executor_notify_handler(struct action_executor
*executor
,
120 const struct action_work_item
*,
121 struct action_work_subitem
*);
122 static int action_executor_start_session_handler(
123 struct action_executor
*executor
,
124 const struct action_work_item
*,
125 struct action_work_subitem
*);
126 static int action_executor_stop_session_handler(
127 struct action_executor
*executor
,
128 const struct action_work_item
*,
129 struct action_work_subitem
*);
130 static int action_executor_rotate_session_handler(
131 struct action_executor
*executor
,
132 const struct action_work_item
*,
133 struct action_work_subitem
*);
134 static int action_executor_snapshot_session_handler(
135 struct action_executor
*executor
,
136 const struct action_work_item
*,
137 struct action_work_subitem
*);
138 static int action_executor_list_handler(struct action_executor
*executor
,
139 const struct action_work_item
*,
140 struct action_work_subitem
*);
141 static int action_executor_generic_handler(struct action_executor
*executor
,
142 const struct action_work_item
*,
143 struct action_work_subitem
*);
145 static const action_executor_handler action_executors
[] = {
146 [LTTNG_ACTION_TYPE_NOTIFY
] = action_executor_notify_handler
,
147 [LTTNG_ACTION_TYPE_START_SESSION
] = action_executor_start_session_handler
,
148 [LTTNG_ACTION_TYPE_STOP_SESSION
] = action_executor_stop_session_handler
,
149 [LTTNG_ACTION_TYPE_ROTATE_SESSION
] = action_executor_rotate_session_handler
,
150 [LTTNG_ACTION_TYPE_SNAPSHOT_SESSION
] = action_executor_snapshot_session_handler
,
151 [LTTNG_ACTION_TYPE_LIST
] = action_executor_list_handler
,
154 /* Forward declaration */
155 static int add_action_to_subitem_array(struct lttng_action
*action
,
156 struct lttng_dynamic_array
*subitems
);
158 static int populate_subitem_array_from_trigger(struct lttng_trigger
*trigger
,
159 struct lttng_dynamic_array
*subitems
);
161 static void action_work_subitem_destructor(void *element
)
163 struct action_work_subitem
*subitem
= element
;
165 lttng_action_put(subitem
->action
);
168 static const char *get_action_name(const struct lttng_action
*action
)
170 const enum lttng_action_type action_type
= lttng_action_get_type(action
);
172 assert(action_type
!= LTTNG_ACTION_TYPE_UNKNOWN
);
174 return lttng_action_type_string(action_type
);
177 /* Check if this trigger allowed to interect with a given session. */
178 static bool is_trigger_allowed_for_session(const struct lttng_trigger
*trigger
,
179 struct ltt_session
*session
)
181 bool is_allowed
= false;
182 const struct lttng_credentials session_creds
= {
183 .uid
= LTTNG_OPTIONAL_INIT_VALUE(session
->uid
),
184 .gid
= LTTNG_OPTIONAL_INIT_VALUE(session
->gid
),
186 /* Can never be NULL. */
187 const struct lttng_credentials
*trigger_creds
=
188 lttng_trigger_get_credentials(trigger
);
190 is_allowed
= (lttng_credentials_is_equal_uid(trigger_creds
, &session_creds
)) ||
191 (lttng_credentials_get_uid(trigger_creds
) == 0);
193 WARN("Trigger is not allowed to interact with session `%s`: session uid = %ld, session gid = %ld, trigger uid = %ld",
195 (long int) session
->uid
,
196 (long int) session
->gid
,
197 (long int) lttng_credentials_get_uid(trigger_creds
));
203 static const char *get_trigger_name(const struct lttng_trigger
*trigger
)
205 const char *trigger_name
;
206 enum lttng_trigger_status trigger_status
;
208 trigger_status
= lttng_trigger_get_name(trigger
, &trigger_name
);
209 switch (trigger_status
) {
210 case LTTNG_TRIGGER_STATUS_OK
:
212 case LTTNG_TRIGGER_STATUS_UNSET
:
213 trigger_name
= "(anonymous)";
216 trigger_name
= "(failed to get name)";
223 static int client_handle_transmission_status(
224 struct notification_client
*client
,
225 enum client_transmission_status status
,
229 struct action_executor
*executor
= user_data
;
230 bool update_communication
= true;
233 case CLIENT_TRANSMISSION_STATUS_COMPLETE
:
234 DBG("Successfully sent full notification to client, client_id = %" PRIu64
,
236 update_communication
= false;
238 case CLIENT_TRANSMISSION_STATUS_QUEUED
:
239 DBG("Queued notification in client outgoing buffer, client_id = %" PRIu64
,
242 case CLIENT_TRANSMISSION_STATUS_FAIL
:
243 DBG("Communication error occurred while sending notification to client, client_id = %" PRIu64
,
247 ERR("Fatal error encoutered while sending notification to client, client_id = %" PRIu64
,
253 if (!update_communication
) {
257 /* Safe to read client's id without locking as it is immutable. */
258 ret
= notification_thread_client_communication_update(
259 executor
->notification_thread_handle
, client
->id
,
265 static int action_executor_notify_handler(struct action_executor
*executor
,
266 const struct action_work_item
*work_item
,
267 struct action_work_subitem
*item
)
269 return notification_client_list_send_evaluation(work_item
->client_list
,
271 work_item
->evaluation
,
272 work_item
->object_creds
.is_set
?
273 &(work_item
->object_creds
.value
) :
275 client_handle_transmission_status
, executor
);
278 static int action_executor_start_session_handler(
279 struct action_executor
*executor
,
280 const struct action_work_item
*work_item
,
281 struct action_work_subitem
*item
)
284 const char *session_name
;
285 enum lttng_action_status action_status
;
286 struct ltt_session
*session
;
287 enum lttng_error_code cmd_ret
;
288 struct lttng_action
*action
= item
->action
;
290 action_status
= lttng_action_start_session_get_session_name(
291 action
, &session_name
);
292 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
293 ERR("Failed to get session name from `%s` action",
294 get_action_name(action
));
300 * Validate if at the moment of the action was queued the session
301 * existed. If not skip the action altogether.
303 if (!item
->context
.session_id
.is_set
) {
304 DBG("Session `%s` was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
305 session_name
, get_action_name(action
),
306 get_trigger_name(work_item
->trigger
));
307 lttng_action_increase_execution_failure_count(action
);
313 session
= session_find_by_name(session_name
);
315 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%s`",
316 session_name
, get_action_name(action
),
317 get_trigger_name(work_item
->trigger
));
318 goto error_unlock_list
;
322 * Check if the session id is the same as when the work item was
325 if (session
->id
!= LTTNG_OPTIONAL_GET(item
->context
.session_id
)) {
326 DBG("Session id for session `%s` (id: %" PRIu64
327 " is not the same that was sampled (id: %" PRIu64
328 " at the moment the work item was enqueued for %s` action of trigger `%s`",
329 session_name
, session
->id
,
330 LTTNG_OPTIONAL_GET(item
->context
.session_id
),
331 get_action_name(action
),
332 get_trigger_name(work_item
->trigger
));
334 goto error_unlock_list
;
337 session_lock(session
);
338 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
339 goto error_dispose_session
;
342 cmd_ret
= cmd_start_trace(session
);
345 DBG("Successfully started session `%s` on behalf of trigger `%s`",
346 session_name
, get_trigger_name(work_item
->trigger
));
348 case LTTNG_ERR_TRACE_ALREADY_STARTED
:
349 DBG("Attempted to start session `%s` on behalf of trigger `%s` but it was already started",
350 session_name
, get_trigger_name(work_item
->trigger
));
353 WARN("Failed to start session `%s` on behalf of trigger `%s`: %s",
354 session_name
, get_trigger_name(work_item
->trigger
),
355 lttng_strerror(-cmd_ret
));
356 lttng_action_increase_execution_failure_count(action
);
360 error_dispose_session
:
361 session_unlock(session
);
362 session_put(session
);
364 session_unlock_list();
369 static int action_executor_stop_session_handler(
370 struct action_executor
*executor
,
371 const struct action_work_item
*work_item
,
372 struct action_work_subitem
*item
)
375 const char *session_name
;
376 enum lttng_action_status action_status
;
377 struct ltt_session
*session
;
378 enum lttng_error_code cmd_ret
;
379 struct lttng_action
*action
= item
->action
;
381 action_status
= lttng_action_stop_session_get_session_name(
382 action
, &session_name
);
383 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
384 ERR("Failed to get session name from `%s` action",
385 get_action_name(action
));
391 * Validate if, at the moment the action was queued, the target session
392 * existed. If not, skip the action altogether.
394 if (!item
->context
.session_id
.is_set
) {
395 DBG("Session `%s` was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
396 session_name
, get_action_name(action
),
397 get_trigger_name(work_item
->trigger
));
398 lttng_action_increase_execution_failure_count(action
);
404 session
= session_find_by_name(session_name
);
406 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%s`",
407 session_name
, get_action_name(action
),
408 get_trigger_name(work_item
->trigger
));
409 lttng_action_increase_execution_failure_count(action
);
410 goto error_unlock_list
;
414 * Check if the session id is the same as when the work item was
417 if (session
->id
!= LTTNG_OPTIONAL_GET(item
->context
.session_id
)) {
418 DBG("Session id for session `%s` (id: %" PRIu64
419 " is not the same that was sampled (id: %" PRIu64
420 " at the moment the work item was enqueued for %s` action of trigger `%s`",
421 session_name
, session
->id
,
422 LTTNG_OPTIONAL_GET(item
->context
.session_id
),
423 get_action_name(action
),
424 get_trigger_name(work_item
->trigger
));
426 goto error_unlock_list
;
429 session_lock(session
);
430 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
431 goto error_dispose_session
;
434 cmd_ret
= cmd_stop_trace(session
);
437 DBG("Successfully stopped session `%s` on behalf of trigger `%s`",
438 session_name
, get_trigger_name(work_item
->trigger
));
440 case LTTNG_ERR_TRACE_ALREADY_STOPPED
:
441 DBG("Attempted to stop session `%s` on behalf of trigger `%s` but it was already stopped",
442 session_name
, get_trigger_name(work_item
->trigger
));
445 WARN("Failed to stop session `%s` on behalf of trigger `%s`: %s",
446 session_name
, get_trigger_name(work_item
->trigger
),
447 lttng_strerror(-cmd_ret
));
448 lttng_action_increase_execution_failure_count(action
);
452 error_dispose_session
:
453 session_unlock(session
);
454 session_put(session
);
456 session_unlock_list();
461 static int action_executor_rotate_session_handler(
462 struct action_executor
*executor
,
463 const struct action_work_item
*work_item
,
464 struct action_work_subitem
*item
)
467 const char *session_name
;
468 enum lttng_action_status action_status
;
469 struct ltt_session
*session
;
470 enum lttng_error_code cmd_ret
;
471 struct lttng_action
*action
= item
->action
;
473 action_status
= lttng_action_rotate_session_get_session_name(
474 action
, &session_name
);
475 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
476 ERR("Failed to get session name from `%s` action",
477 get_action_name(action
));
483 * Validate if, at the moment the action was queued, the target session
484 * existed. If not, skip the action altogether.
486 if (!item
->context
.session_id
.is_set
) {
487 DBG("Session `%s` was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
488 session_name
, get_action_name(action
),
489 get_trigger_name(work_item
->trigger
));
490 lttng_action_increase_execution_failure_count(action
);
496 session
= session_find_by_name(session_name
);
498 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%s`",
499 session_name
, get_action_name(action
),
500 get_trigger_name(work_item
->trigger
));
501 lttng_action_increase_execution_failure_count(action
);
502 goto error_unlock_list
;
506 * Check if the session id is the same as when the work item was
509 if (session
->id
!= LTTNG_OPTIONAL_GET(item
->context
.session_id
)) {
510 DBG("Session id for session `%s` (id: %" PRIu64
511 " is not the same that was sampled (id: %" PRIu64
512 " at the moment the work item was enqueued for %s` action of trigger `%s`",
513 session_name
, session
->id
,
514 LTTNG_OPTIONAL_GET(item
->context
.session_id
),
515 get_action_name(action
),
516 get_trigger_name(work_item
->trigger
));
518 goto error_unlock_list
;
521 session_lock(session
);
522 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
523 goto error_dispose_session
;
526 cmd_ret
= cmd_rotate_session(session
, NULL
, false,
527 LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED
);
530 DBG("Successfully started rotation of session `%s` on behalf of trigger `%s`",
531 session_name
, get_trigger_name(work_item
->trigger
));
533 case LTTNG_ERR_ROTATION_PENDING
:
534 DBG("Attempted to start a rotation of session `%s` on behalf of trigger `%s` but a rotation is already ongoing",
535 session_name
, get_trigger_name(work_item
->trigger
));
536 lttng_action_increase_execution_failure_count(action
);
538 case LTTNG_ERR_ROTATION_MULTIPLE_AFTER_STOP
:
539 case LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR
:
540 DBG("Attempted to start a rotation of session `%s` on behalf of trigger `%s` but a rotation has already been completed since the last stop or clear",
541 session_name
, get_trigger_name(work_item
->trigger
));
544 WARN("Failed to start a rotation of session `%s` on behalf of trigger `%s`: %s",
545 session_name
, get_trigger_name(work_item
->trigger
),
546 lttng_strerror(-cmd_ret
));
547 lttng_action_increase_execution_failure_count(action
);
551 error_dispose_session
:
552 session_unlock(session
);
553 session_put(session
);
555 session_unlock_list();
560 static int action_executor_snapshot_session_handler(
561 struct action_executor
*executor
,
562 const struct action_work_item
*work_item
,
563 struct action_work_subitem
*item
)
566 const char *session_name
;
567 enum lttng_action_status action_status
;
568 struct ltt_session
*session
;
569 const struct lttng_snapshot_output default_snapshot_output
= {
570 .max_size
= UINT64_MAX
,
572 const struct lttng_snapshot_output
*snapshot_output
=
573 &default_snapshot_output
;
574 enum lttng_error_code cmd_ret
;
575 struct lttng_action
*action
= item
->action
;
578 * Validate if, at the moment the action was queued, the target session
579 * existed. If not, skip the action altogether.
581 if (!item
->context
.session_id
.is_set
) {
582 DBG("Session was not present at the moment the work item was enqueued for %s` action of trigger `%s`",
583 get_action_name(action
),
584 get_trigger_name(work_item
->trigger
));
585 lttng_action_increase_execution_failure_count(action
);
590 action_status
= lttng_action_snapshot_session_get_session_name(
591 action
, &session_name
);
592 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
593 ERR("Failed to get session name from `%s` action",
594 get_action_name(action
));
599 action_status
= lttng_action_snapshot_session_get_output(
600 action
, &snapshot_output
);
601 if (action_status
!= LTTNG_ACTION_STATUS_OK
&&
602 action_status
!= LTTNG_ACTION_STATUS_UNSET
) {
603 ERR("Failed to get output from `%s` action",
604 get_action_name(action
));
610 session
= session_find_by_name(session_name
);
612 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%s`",
613 session_name
, get_action_name(action
),
614 get_trigger_name(work_item
->trigger
));
615 lttng_action_increase_execution_failure_count(action
);
616 goto error_unlock_list
;
620 * Check if the session id is the same as when the work item was
623 if (session
->id
!= LTTNG_OPTIONAL_GET(item
->context
.session_id
)) {
624 DBG("Session id for session `%s` (id: %" PRIu64
625 " is not the same that was sampled (id: %" PRIu64
626 " at the moment the work item was enqueued for %s` action of trigger `%s`",
627 session_name
, session
->id
,
628 LTTNG_OPTIONAL_GET(item
->context
.session_id
),
629 get_action_name(action
),
630 get_trigger_name(work_item
->trigger
));
632 goto error_unlock_list
;
635 session_lock(session
);
636 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
637 goto error_dispose_session
;
640 cmd_ret
= cmd_snapshot_record(session
, snapshot_output
, 0);
643 DBG("Successfully recorded snapshot of session `%s` on behalf of trigger `%s`",
644 session_name
, get_trigger_name(work_item
->trigger
));
647 WARN("Failed to record snapshot of session `%s` on behalf of trigger `%s`: %s",
648 session_name
, get_trigger_name(work_item
->trigger
),
649 lttng_strerror(-cmd_ret
));
650 lttng_action_increase_execution_failure_count(action
);
654 error_dispose_session
:
655 session_unlock(session
);
656 session_put(session
);
658 session_unlock_list();
663 static int action_executor_list_handler(struct action_executor
*executor
,
664 const struct action_work_item
*work_item
,
665 struct action_work_subitem
*item
)
667 ERR("Execution of a list action by the action executor should never occur");
671 static int action_executor_generic_handler(struct action_executor
*executor
,
672 const struct action_work_item
*work_item
,
673 struct action_work_subitem
*item
)
676 struct lttng_action
*action
= item
->action
;
677 const enum lttng_action_type action_type
= lttng_action_get_type(action
);
679 assert(action_type
!= LTTNG_ACTION_TYPE_UNKNOWN
);
681 lttng_action_increase_execution_request_count(action
);
682 if (!lttng_action_should_execute(action
)) {
683 DBG("Policy prevented execution of action `%s` of trigger `%s` action work item %" PRIu64
,
684 get_action_name(action
),
685 get_trigger_name(work_item
->trigger
),
691 lttng_action_increase_execution_count(action
);
692 DBG("Executing action `%s` of trigger `%s` action work item %" PRIu64
,
693 get_action_name(action
),
694 get_trigger_name(work_item
->trigger
),
696 ret
= action_executors
[action_type
](executor
, work_item
, item
);
701 static int action_work_item_execute(struct action_executor
*executor
,
702 struct action_work_item
*work_item
)
707 DBG("Starting execution of action work item %" PRIu64
" of trigger `%s`",
708 work_item
->id
, get_trigger_name(work_item
->trigger
));
710 count
= lttng_dynamic_array_get_count(&work_item
->subitems
);
711 for (i
= 0; i
< count
; i
++) {
712 struct action_work_subitem
*item
;
714 item
= lttng_dynamic_array_get_element(&work_item
->subitems
, i
);
715 ret
= action_executor_generic_handler(
716 executor
, work_item
, item
);
722 DBG("Completed execution of action work item %" PRIu64
" of trigger `%s`",
723 work_item
->id
, get_trigger_name(work_item
->trigger
));
727 static void action_work_item_destroy(struct action_work_item
*work_item
)
729 lttng_trigger_put(work_item
->trigger
);
730 lttng_evaluation_destroy(work_item
->evaluation
);
731 notification_client_list_put(work_item
->client_list
);
732 lttng_dynamic_array_reset(&work_item
->subitems
);
736 static void *action_executor_thread(void *_data
)
738 struct action_executor
*executor
= _data
;
742 health_register(the_health_sessiond
,
743 HEALTH_SESSIOND_TYPE_ACTION_EXECUTOR
);
745 rcu_register_thread();
748 DBG("Entering work execution loop");
749 pthread_mutex_lock(&executor
->work
.lock
);
750 while (!executor
->should_quit
) {
752 struct action_work_item
*work_item
;
754 health_code_update();
755 if (executor
->work
.pending_count
== 0) {
757 DBG("No work items enqueued, entering wait");
758 pthread_cond_wait(&executor
->work
.cond
,
759 &executor
->work
.lock
);
760 DBG("Woke-up from wait");
765 /* Pop item from front of the list with work lock held. */
766 work_item
= cds_list_first_entry(&executor
->work
.list
,
767 struct action_work_item
, list_node
);
768 cds_list_del(&work_item
->list_node
);
769 executor
->work
.pending_count
--;
772 * Work can be performed without holding the work lock,
773 * allowing new items to be queued.
775 pthread_mutex_unlock(&executor
->work
.lock
);
777 /* Execute item only if a trigger is registered. */
778 lttng_trigger_lock(work_item
->trigger
);
779 if (!lttng_trigger_is_registered(work_item
->trigger
)) {
780 const char *trigger_name
= NULL
;
781 uid_t trigger_owner_uid
;
782 enum lttng_trigger_status trigger_status
;
784 trigger_name
= get_trigger_name(work_item
->trigger
);
786 trigger_status
= lttng_trigger_get_owner_uid(
787 work_item
->trigger
, &trigger_owner_uid
);
788 assert(trigger_status
== LTTNG_TRIGGER_STATUS_OK
);
790 DBG("Work item skipped since the associated trigger is no longer registered: work item id = %" PRIu64
", trigger name = '%s', trigger owner uid = %d",
791 work_item
->id
, trigger_name
,
792 (int) trigger_owner_uid
);
797 ret
= action_work_item_execute(executor
, work_item
);
800 lttng_trigger_unlock(work_item
->trigger
);
801 action_work_item_destroy(work_item
);
807 health_code_update();
808 pthread_mutex_lock(&executor
->work
.lock
);
811 if (executor
->should_quit
) {
812 pthread_mutex_unlock(&executor
->work
.lock
);
814 DBG("Left work execution loop");
816 health_code_update();
818 rcu_thread_offline();
819 rcu_unregister_thread();
820 health_unregister(the_health_sessiond
);
825 static bool shutdown_action_executor_thread(void *_data
)
827 struct action_executor
*executor
= _data
;
829 pthread_mutex_lock(&executor
->work
.lock
);
830 executor
->should_quit
= true;
831 pthread_cond_signal(&executor
->work
.cond
);
832 pthread_mutex_unlock(&executor
->work
.lock
);
836 static void clean_up_action_executor_thread(void *_data
)
838 struct action_executor
*executor
= _data
;
840 assert(cds_list_empty(&executor
->work
.list
));
842 pthread_mutex_destroy(&executor
->work
.lock
);
843 pthread_cond_destroy(&executor
->work
.cond
);
847 struct action_executor
*action_executor_create(
848 struct notification_thread_handle
*handle
)
850 struct action_executor
*executor
= zmalloc(sizeof(*executor
));
856 CDS_INIT_LIST_HEAD(&executor
->work
.list
);
857 pthread_cond_init(&executor
->work
.cond
, NULL
);
858 pthread_mutex_init(&executor
->work
.lock
, NULL
);
859 executor
->notification_thread_handle
= handle
;
861 executor
->thread
= lttng_thread_create(THREAD_NAME
,
862 action_executor_thread
, shutdown_action_executor_thread
,
863 clean_up_action_executor_thread
, executor
);
868 void action_executor_destroy(struct action_executor
*executor
)
870 struct action_work_item
*work_item
, *tmp
;
872 /* TODO Wait for work list to drain? */
873 lttng_thread_shutdown(executor
->thread
);
874 pthread_mutex_lock(&executor
->work
.lock
);
875 if (executor
->work
.pending_count
!= 0) {
877 " trigger action%s still queued for execution and will be discarded",
878 executor
->work
.pending_count
,
879 executor
->work
.pending_count
== 1 ? " is" :
883 cds_list_for_each_entry_safe (
884 work_item
, tmp
, &executor
->work
.list
, list_node
) {
885 WARN("Discarding action work item %" PRIu64
886 " associated to trigger `%s`",
887 work_item
->id
, get_trigger_name(work_item
->trigger
));
888 cds_list_del(&work_item
->list_node
);
889 action_work_item_destroy(work_item
);
891 pthread_mutex_unlock(&executor
->work
.lock
);
892 lttng_thread_put(executor
->thread
);
895 /* RCU read-lock must be held by the caller. */
896 enum action_executor_status
action_executor_enqueue_trigger(
897 struct action_executor
*executor
,
898 struct lttng_trigger
*trigger
,
899 struct lttng_evaluation
*evaluation
,
900 const struct lttng_credentials
*object_creds
,
901 struct notification_client_list
*client_list
)
904 enum action_executor_status executor_status
= ACTION_EXECUTOR_STATUS_OK
;
905 const uint64_t work_item_id
= executor
->next_work_item_id
++;
906 struct action_work_item
*work_item
;
911 pthread_mutex_lock(&executor
->work
.lock
);
912 /* Check for queue overflow. */
913 if (executor
->work
.pending_count
>= MAX_QUEUED_WORK_COUNT
) {
914 /* Most likely spammy, remove if it is the case. */
915 DBG("Refusing to enqueue action for trigger (overflow): trigger name = `%s`, work item id = %" PRIu64
,
916 get_trigger_name(trigger
), work_item_id
);
917 executor_status
= ACTION_EXECUTOR_STATUS_OVERFLOW
;
921 work_item
= zmalloc(sizeof(*work_item
));
923 PERROR("Failed to allocate action executor work item: trigger name = '%s'",
924 get_trigger_name(trigger
));
925 executor_status
= ACTION_EXECUTOR_STATUS_ERROR
;
929 lttng_trigger_get(trigger
);
931 const bool reference_acquired
=
932 notification_client_list_get(client_list
);
934 assert(reference_acquired
);
937 *work_item
= (typeof(*work_item
)){
940 /* Ownership transferred to the work item. */
941 .evaluation
= evaluation
,
943 .is_set
= !!object_creds
,
944 .value
= object_creds
? *object_creds
:
945 (typeof(work_item
->object_creds
.value
)) {},
947 .client_list
= client_list
,
948 .list_node
= CDS_LIST_HEAD_INIT(work_item
->list_node
),
953 /* Build the array of action work subitems for the passed trigger. */
954 lttng_dynamic_array_init(&work_item
->subitems
,
955 sizeof(struct action_work_subitem
),
956 action_work_subitem_destructor
);
958 ret
= populate_subitem_array_from_trigger(
959 trigger
, &work_item
->subitems
);
961 ERR("Failed to populate work item sub items on behalf of trigger: trigger name = `%s`",
962 get_trigger_name(trigger
));
963 executor_status
= ACTION_EXECUTOR_STATUS_ERROR
;
967 cds_list_add_tail(&work_item
->list_node
, &executor
->work
.list
);
968 executor
->work
.pending_count
++;
969 DBG("Enqueued action for trigger: trigger name = `%s`, work item id = %" PRIu64
,
970 get_trigger_name(trigger
), work_item_id
);
975 pthread_cond_signal(&executor
->work
.cond
);
978 pthread_mutex_unlock(&executor
->work
.lock
);
979 lttng_evaluation_destroy(evaluation
);
980 return executor_status
;
983 static int add_action_to_subitem_array(struct lttng_action
*action
,
984 struct lttng_dynamic_array
*subitems
)
987 enum lttng_action_type type
= lttng_action_get_type(action
);
988 const char *session_name
= NULL
;
989 enum lttng_action_status status
;
990 struct action_work_subitem subitem
= {
993 .session_id
= LTTNG_OPTIONAL_INIT_UNSET
,
1000 if (type
== LTTNG_ACTION_TYPE_LIST
) {
1001 unsigned int count
, i
;
1003 status
= lttng_action_list_get_count(action
, &count
);
1004 assert(status
== LTTNG_ACTION_STATUS_OK
);
1006 for (i
= 0; i
< count
; i
++) {
1007 struct lttng_action
*inner_action
= NULL
;
1009 inner_action
= lttng_action_list_borrow_mutable_at_index(
1011 assert(inner_action
);
1012 ret
= add_action_to_subitem_array(
1013 inner_action
, subitems
);
1020 * Go directly to the end since there is no need to add the
1021 * list action by itself to the subitems array.
1026 /* Gather execution context. */
1028 case LTTNG_ACTION_TYPE_NOTIFY
:
1030 case LTTNG_ACTION_TYPE_START_SESSION
:
1031 status
= lttng_action_start_session_get_session_name(
1032 action
, &session_name
);
1033 assert(status
== LTTNG_ACTION_STATUS_OK
);
1035 case LTTNG_ACTION_TYPE_STOP_SESSION
:
1036 status
= lttng_action_stop_session_get_session_name(
1037 action
, &session_name
);
1038 assert(status
== LTTNG_ACTION_STATUS_OK
);
1040 case LTTNG_ACTION_TYPE_ROTATE_SESSION
:
1041 status
= lttng_action_rotate_session_get_session_name(
1042 action
, &session_name
);
1043 assert(status
== LTTNG_ACTION_STATUS_OK
);
1045 case LTTNG_ACTION_TYPE_SNAPSHOT_SESSION
:
1046 status
= lttng_action_snapshot_session_get_session_name(
1047 action
, &session_name
);
1048 assert(status
== LTTNG_ACTION_STATUS_OK
);
1050 case LTTNG_ACTION_TYPE_LIST
:
1051 case LTTNG_ACTION_TYPE_UNKNOWN
:
1059 * Fetch the session execution context info as needed.
1060 * Note that we could decide to not add an action for which we know the
1061 * execution will not happen (i.e no session exists for that name). For
1062 * now we leave the decision to skip to the action executor for sake of
1063 * simplicity and consistency.
1065 if (session_name
!= NULL
) {
1066 uint64_t session_id
;
1069 * Instantaneous sampling of the session id if present.
1071 * This method is preferred over `sessiond_find_by_name` then
1072 * fetching the session'd id since `sessiond_find_by_name`
1073 * requires the session list lock to be taken.
1075 * Taking the session list lock can lead to a deadlock
1076 * between the action executor and the notification thread
1077 * (caller of add_action_to_subitem_array). It is okay if the
1078 * session state changes between the enqueuing time and the
1079 * execution time. The execution context is validated at
1082 if (sample_session_id_by_name(session_name
, &session_id
)) {
1083 LTTNG_OPTIONAL_SET(&subitem
.context
.session_id
,
1088 /* Get a reference to the action. */
1089 lttng_action_get(action
);
1090 subitem
.action
= action
;
1092 ret
= lttng_dynamic_array_add_element(subitems
, &subitem
);
1094 ERR("Failed to add work subitem to the subitem array");
1095 lttng_action_put(action
);
1104 static int populate_subitem_array_from_trigger(struct lttng_trigger
*trigger
,
1105 struct lttng_dynamic_array
*subitems
)
1107 struct lttng_action
*action
;
1109 action
= lttng_trigger_get_action(trigger
);
1112 return add_action_to_subitem_array(action
, subitems
);