2 * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
4 * SPDX-License-Identifier: GPL-2.0-only
8 #include "action-executor.hpp"
10 #include "health-sessiond.hpp"
11 #include "lttng-sessiond.hpp"
12 #include "notification-thread-internal.hpp"
13 #include "session.hpp"
16 #include <common/dynamic-array.hpp>
17 #include <common/macros.hpp>
18 #include <common/optional.hpp>
19 #include <common/urcu.hpp>
21 #include <lttng/action/action-internal.hpp>
22 #include <lttng/action/list-internal.hpp>
23 #include <lttng/action/list.h>
24 #include <lttng/action/notify-internal.hpp>
25 #include <lttng/action/notify.h>
26 #include <lttng/action/rotate-session.h>
27 #include <lttng/action/snapshot-session.h>
28 #include <lttng/action/start-session.h>
29 #include <lttng/action/stop-session.h>
30 #include <lttng/condition/evaluation.h>
31 #include <lttng/condition/event-rule-matches-internal.hpp>
32 #include <lttng/lttng-error.h>
33 #include <lttng/trigger/trigger-internal.hpp>
38 #include <urcu/list.h>
40 #define THREAD_NAME "Action Executor"
41 #define MAX_QUEUED_WORK_COUNT 8192
43 struct action_executor
{
44 struct lttng_thread
*thread
;
45 struct notification_thread_handle
*notification_thread_handle
;
47 uint64_t pending_count
;
48 struct cds_list_head list
;
53 uint64_t next_work_item_id
;
58 * A work item is composed of a dynamic array of sub-items which
59 * represent a flattened, and augmented, version of a trigger's actions.
61 * We cannot rely solely on the trigger's actions since each action can have an
62 * execution context we need to comply with.
64 * The notion of execution context is required since for some actions the
65 * associated object are referenced by name and not by id. This can lead to
66 * a number of ambiguities when executing an action work item.
68 * For example, let's take a simple trigger such as:
69 * - condition: ust event a
70 * - action: start session S
72 * At time T, session S exists.
73 * At T + 1, the event A is hit.
74 * At T + 2, the tracer event notification is received and the work item is
75 * queued. Here session S have an id of 1.
76 * At T + 3, the session S is destroyed and a new session S is created, with a
77 * resulting id of 200.
78 * At T +4, the work item is popped from the queue and begin execution and will
79 * start session S with an id of 200 instead of the session S id 1 that was
80 * present at the queuing phase.
82 * The context to be respected is the one when the work item is queued. If the
83 * execution context is not the same at the moment of execution, we skip the
84 * execution of that sub-item.
86 * It is the same policy in regards to the validity of the associated
87 * trigger object at the moment of execution, if the trigger is found to be
88 * unregistered, the execution is skipped.
90 struct action_work_item
{
94 * The actions to be executed with their respective execution context.
95 * See struct `action_work_subitem`.
97 struct lttng_dynamic_array subitems
;
99 /* Execution context data */
100 struct lttng_trigger
*trigger
;
101 struct lttng_evaluation
*evaluation
;
102 struct notification_client_list
*client_list
;
103 LTTNG_OPTIONAL(struct lttng_credentials
) object_creds
;
104 struct cds_list_head list_node
;
107 struct action_work_subitem
{
108 struct lttng_action
*action
;
110 /* Used by actions targeting a session. */
111 LTTNG_OPTIONAL(uint64_t) session_id
;
117 * Only return non-zero on a fatal error that should shut down the action
120 using action_executor_handler
= int (*)(struct action_executor
*,
121 const struct action_work_item
*,
122 struct action_work_subitem
*);
124 static int action_executor_notify_handler(struct action_executor
*executor
,
125 const struct action_work_item
*,
126 struct action_work_subitem
*);
127 static int action_executor_start_session_handler(struct action_executor
*executor
,
128 const struct action_work_item
*,
129 struct action_work_subitem
*);
130 static int action_executor_stop_session_handler(struct action_executor
*executor
,
131 const struct action_work_item
*,
132 struct action_work_subitem
*);
133 static int action_executor_rotate_session_handler(struct action_executor
*executor
,
134 const struct action_work_item
*,
135 struct action_work_subitem
*);
136 static int action_executor_snapshot_session_handler(struct action_executor
*executor
,
137 const struct action_work_item
*,
138 struct action_work_subitem
*);
139 static int action_executor_list_handler(struct action_executor
*executor
,
140 const struct action_work_item
*,
141 struct action_work_subitem
*);
142 static int action_executor_generic_handler(struct action_executor
*executor
,
143 const struct action_work_item
*,
144 struct action_work_subitem
*);
146 static const action_executor_handler action_executors
[] = {
147 action_executor_notify_handler
, action_executor_start_session_handler
,
148 action_executor_stop_session_handler
, action_executor_rotate_session_handler
,
149 action_executor_snapshot_session_handler
, action_executor_list_handler
,
152 /* Forward declaration */
153 static int add_action_to_subitem_array(struct lttng_action
*action
,
154 struct lttng_dynamic_array
*subitems
);
156 static int populate_subitem_array_from_trigger(struct lttng_trigger
*trigger
,
157 struct lttng_dynamic_array
*subitems
);
159 static void action_work_subitem_destructor(void *element
)
161 struct action_work_subitem
*subitem
= (action_work_subitem
*) element
;
163 lttng_action_put(subitem
->action
);
166 static const char *get_action_name(const struct lttng_action
*action
)
168 const enum lttng_action_type action_type
= lttng_action_get_type(action
);
170 LTTNG_ASSERT(action_type
!= LTTNG_ACTION_TYPE_UNKNOWN
);
172 return lttng_action_type_string(action_type
);
175 /* Check if this trigger allowed to interect with a given session. */
176 static bool is_trigger_allowed_for_session(const struct lttng_trigger
*trigger
,
177 const ltt_session::locked_ref
& session
)
179 bool is_allowed
= false;
180 const struct lttng_credentials session_creds
= {
181 .uid
= LTTNG_OPTIONAL_INIT_VALUE(session
->uid
),
182 .gid
= LTTNG_OPTIONAL_INIT_VALUE(session
->gid
),
184 /* Can never be NULL. */
185 const struct lttng_credentials
*trigger_creds
= lttng_trigger_get_credentials(trigger
);
187 is_allowed
= (lttng_credentials_is_equal_uid(trigger_creds
, &session_creds
)) ||
188 (lttng_credentials_get_uid(trigger_creds
) == 0);
190 WARN("Trigger is not allowed to interact with session `%s`: session uid = %ld, session gid = %ld, trigger uid = %ld",
192 (long int) session
->uid
,
193 (long int) session
->gid
,
194 (long int) lttng_credentials_get_uid(trigger_creds
));
200 static const char *get_trigger_name(const struct lttng_trigger
*trigger
)
202 const char *trigger_name
;
203 enum lttng_trigger_status trigger_status
;
205 trigger_status
= lttng_trigger_get_name(trigger
, &trigger_name
);
206 switch (trigger_status
) {
207 case LTTNG_TRIGGER_STATUS_OK
:
209 case LTTNG_TRIGGER_STATUS_UNSET
:
210 trigger_name
= "(anonymous)";
213 trigger_name
= "(failed to get name)";
220 static int client_handle_transmission_status(struct notification_client
*client
,
221 enum client_transmission_status status
,
225 struct action_executor
*executor
= (action_executor
*) user_data
;
226 bool update_communication
= true;
229 case CLIENT_TRANSMISSION_STATUS_COMPLETE
:
230 DBG("Successfully sent full notification to client, client_id = %" PRIu64
,
233 * There is no need to wake the (e)poll thread. If it was waiting for
234 * "out" events on the client's socket, it will see that no payload
235 * in queued and will unsubscribe from that event.
237 * In the other cases, we have to wake the the (e)poll thread to either
238 * handle the error on the client or to get it to monitor the client "out"
241 update_communication
= false;
243 case CLIENT_TRANSMISSION_STATUS_QUEUED
:
244 DBG("Queued notification in client outgoing buffer, client_id = %" PRIu64
,
247 case CLIENT_TRANSMISSION_STATUS_FAIL
:
248 DBG("Communication error occurred while sending notification to client, client_id = %" PRIu64
,
252 ERR("Fatal error encoutered while sending notification to client, client_id = %" PRIu64
,
258 if (!update_communication
) {
262 /* Safe to read client's id without locking as it is immutable. */
263 ret
= notification_thread_client_communication_update(
264 executor
->notification_thread_handle
, client
->id
, status
);
269 static int action_executor_notify_handler(struct action_executor
*executor
,
270 const struct action_work_item
*work_item
,
271 struct action_work_subitem
*item
__attribute__((unused
)))
273 return notification_client_list_send_evaluation(
274 work_item
->client_list
,
276 work_item
->evaluation
,
277 work_item
->object_creds
.is_set
? &(work_item
->object_creds
.value
) : nullptr,
278 client_handle_transmission_status
,
282 static int action_executor_start_session_handler(struct action_executor
*executor
283 __attribute__((unused
)),
284 const struct action_work_item
*work_item
,
285 struct action_work_subitem
*item
)
287 const char *session_name
;
288 enum lttng_action_status action_status
;
289 enum lttng_error_code cmd_ret
;
290 struct lttng_action
*action
= item
->action
;
292 lttng::urcu::read_lock_guard read_lock
;
294 action_status
= lttng_action_start_session_get_session_name(action
, &session_name
);
295 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
296 ERR("Failed to get session name from `%s` action", get_action_name(action
));
301 * Validate if at the moment of the action was queued the session
302 * existed. If not skip the action altogether.
304 if (!item
->context
.session_id
.is_set
) {
305 DBG("Session `%s` was not present at the moment the work item was enqueued for `%s` action of trigger `%s`",
307 get_action_name(action
),
308 get_trigger_name(work_item
->trigger
));
309 lttng_action_increase_execution_failure_count(action
);
314 * Mind the order of the declaration of list_lock vs session:
315 * the session list lock must always be released _after_ the release of
316 * a session's reference (the destruction of a ref/locked_ref) to ensure
317 * since the reference's release may unpublish the session from the list of
320 const auto list_lock
= lttng::sessiond::lock_session_list();
322 const auto session
= ltt_session::find_locked_session(
323 LTTNG_OPTIONAL_GET(item
->context
.session_id
));
325 if (session
->destroyed
) {
326 DBG("Session `%s` with id = %" PRIu64
327 " is flagged as destroyed. Skipping: action = `%s`, trigger = `%s`",
330 get_action_name(action
),
331 get_trigger_name(work_item
->trigger
));
335 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
339 cmd_ret
= (lttng_error_code
) cmd_start_trace(session
);
342 DBG("Successfully started session `%s` on behalf of trigger `%s`",
344 get_trigger_name(work_item
->trigger
));
346 case LTTNG_ERR_TRACE_ALREADY_STARTED
:
347 DBG("Attempted to start session `%s` on behalf of trigger `%s` but it was already started",
349 get_trigger_name(work_item
->trigger
));
352 WARN("Failed to start session `%s` on behalf of trigger `%s`: %s",
354 get_trigger_name(work_item
->trigger
),
355 lttng_strerror(-cmd_ret
));
356 lttng_action_increase_execution_failure_count(action
);
359 } catch (const lttng::sessiond::exceptions::session_not_found_error
& ex
) {
360 DBG_FMT("Failed to execution trigger action: {}, action=`{}`, trigger_name=`{}`, location='{}'",
363 get_action_name(action
),
364 get_trigger_name(work_item
->trigger
),
366 lttng_action_increase_execution_failure_count(action
);
372 static int action_executor_stop_session_handler(struct action_executor
*executor
373 __attribute__((unused
)),
374 const struct action_work_item
*work_item
,
375 struct action_work_subitem
*item
)
377 const char *session_name
;
378 enum lttng_action_status action_status
;
379 enum lttng_error_code cmd_ret
;
380 struct lttng_action
*action
= item
->action
;
382 lttng::urcu::read_lock_guard read_lock
;
384 action_status
= lttng_action_stop_session_get_session_name(action
, &session_name
);
385 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
386 ERR("Failed to get session name from `%s` action", 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`",
397 get_action_name(action
),
398 get_trigger_name(work_item
->trigger
));
399 lttng_action_increase_execution_failure_count(action
);
404 * Mind the order of the declaration of list_lock vs session:
405 * the session list lock must always be released _after_ the release of
406 * a session's reference (the destruction of a ref/locked_ref) to ensure
407 * since the reference's release may unpublish the session from the list of
410 const auto list_lock
= lttng::sessiond::lock_session_list();
413 const auto session
= ltt_session::find_locked_session(
414 LTTNG_OPTIONAL_GET(item
->context
.session_id
));
416 if (session
->destroyed
) {
417 DBG("Session `%s` with id = %" PRIu64
418 " is flagged as destroyed. Skipping: action = `%s`, trigger = `%s`",
421 get_action_name(action
),
422 get_trigger_name(work_item
->trigger
));
426 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
430 cmd_ret
= (lttng_error_code
) cmd_stop_trace(session
);
433 DBG("Successfully stopped session `%s` on behalf of trigger `%s`",
435 get_trigger_name(work_item
->trigger
));
437 case LTTNG_ERR_TRACE_ALREADY_STOPPED
:
438 DBG("Attempted to stop session `%s` on behalf of trigger `%s` but it was already stopped",
440 get_trigger_name(work_item
->trigger
));
443 WARN("Failed to stop session `%s` on behalf of trigger `%s`: %s",
445 get_trigger_name(work_item
->trigger
),
446 lttng_strerror(-cmd_ret
));
447 lttng_action_increase_execution_failure_count(action
);
450 } catch (const lttng::sessiond::exceptions::session_not_found_error
& ex
) {
451 DBG_FMT("Failed to execution trigger action: {}, action=`{}`, trigger_name=`{}`, location='{}'",
454 get_action_name(action
),
455 get_trigger_name(work_item
->trigger
),
457 lttng_action_increase_execution_failure_count(action
);
463 static int action_executor_rotate_session_handler(struct action_executor
*executor
464 __attribute__((unused
)),
465 const struct action_work_item
*work_item
,
466 struct action_work_subitem
*item
)
468 const char *session_name
;
469 enum lttng_action_status action_status
;
470 enum lttng_error_code cmd_ret
;
471 struct lttng_action
*action
= item
->action
;
473 lttng::urcu::read_lock_guard read_lock
;
475 action_status
= lttng_action_rotate_session_get_session_name(action
, &session_name
);
476 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
477 ERR("Failed to get session name from `%s` action", get_action_name(action
));
482 * Validate if, at the moment the action was queued, the target session
483 * existed. If not, skip the action altogether.
485 if (!item
->context
.session_id
.is_set
) {
486 DBG("Session `%s` was not present at the moment the work item was enqueued for `%s` action of trigger `%s`",
488 get_action_name(action
),
489 get_trigger_name(work_item
->trigger
));
490 lttng_action_increase_execution_failure_count(action
);
495 * Mind the order of the declaration of list_lock vs session:
496 * the session list lock must always be released _after_ the release of
497 * a session's reference (the destruction of a ref/locked_ref) to ensure
498 * since the reference's release may unpublish the session from the list of
501 const auto list_lock
= lttng::sessiond::lock_session_list();
503 const auto session
= ltt_session::find_locked_session(
504 LTTNG_OPTIONAL_GET(item
->context
.session_id
));
506 if (session
->destroyed
) {
507 DBG("Session `%s` with id = %" PRIu64
508 " is flagged as destroyed. Skipping: action = `%s`, trigger = `%s`",
511 get_action_name(action
),
512 get_trigger_name(work_item
->trigger
));
516 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
520 cmd_ret
= (lttng_error_code
) cmd_rotate_session(
521 session
, nullptr, false, LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED
);
524 DBG("Successfully started rotation of session `%s` on behalf of trigger `%s`",
526 get_trigger_name(work_item
->trigger
));
528 case LTTNG_ERR_ROTATION_PENDING
:
529 DBG("Attempted to start a rotation of session `%s` on behalf of trigger `%s` but a rotation is already ongoing",
531 get_trigger_name(work_item
->trigger
));
532 lttng_action_increase_execution_failure_count(action
);
534 case LTTNG_ERR_ROTATION_MULTIPLE_AFTER_STOP
:
535 case LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR
:
536 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",
538 get_trigger_name(work_item
->trigger
));
541 WARN("Failed to start a rotation of session `%s` on behalf of trigger `%s`: %s",
543 get_trigger_name(work_item
->trigger
),
544 lttng_strerror(-cmd_ret
));
545 lttng_action_increase_execution_failure_count(action
);
548 } catch (const lttng::sessiond::exceptions::session_not_found_error
& ex
) {
549 DBG_FMT("Failed to execution trigger action: {}, action=`{}`, trigger_name=`{}`, location='{}'",
552 get_action_name(action
),
553 get_trigger_name(work_item
->trigger
),
555 lttng_action_increase_execution_failure_count(action
);
561 static int action_executor_snapshot_session_handler(struct action_executor
*executor
562 __attribute__((unused
)),
563 const struct action_work_item
*work_item
,
564 struct action_work_subitem
*item
)
566 const char *session_name
;
567 enum lttng_action_status action_status
;
568 lttng_snapshot_output default_snapshot_output
;
569 const struct lttng_snapshot_output
*snapshot_output
= &default_snapshot_output
;
570 enum lttng_error_code cmd_ret
;
571 struct lttng_action
*action
= item
->action
;
573 default_snapshot_output
.max_size
= UINT64_MAX
;
575 lttng::urcu::read_lock_guard read_lock
;
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
);
589 action_status
= lttng_action_snapshot_session_get_session_name(action
, &session_name
);
590 if (action_status
!= LTTNG_ACTION_STATUS_OK
) {
591 ERR("Failed to get session name from `%s` action", get_action_name(action
));
595 action_status
= lttng_action_snapshot_session_get_output(action
, &snapshot_output
);
596 if (action_status
!= LTTNG_ACTION_STATUS_OK
&& action_status
!= LTTNG_ACTION_STATUS_UNSET
) {
597 ERR("Failed to get output from `%s` action", get_action_name(action
));
602 * Mind the order of the declaration of list_lock vs session:
603 * the session list lock must always be released _after_ the release of
604 * a session's reference (the destruction of a ref/locked_ref) to ensure
605 * since the reference's release may unpublish the session from the list of
608 const auto list_lock
= lttng::sessiond::lock_session_list();
610 const auto session
= ltt_session::find_locked_session(
611 LTTNG_OPTIONAL_GET(item
->context
.session_id
));
613 if (session
->destroyed
) {
614 DBG("Session `%s` with id = %" PRIu64
615 " is flagged as destroyed. Skipping: action = `%s`, trigger = `%s`",
618 get_action_name(action
),
619 get_trigger_name(work_item
->trigger
));
623 if (!is_trigger_allowed_for_session(work_item
->trigger
, session
)) {
627 cmd_ret
= (lttng_error_code
) cmd_snapshot_record(session
, snapshot_output
, 0);
630 DBG("Successfully recorded snapshot of session `%s` on behalf of trigger `%s`",
632 get_trigger_name(work_item
->trigger
));
635 WARN("Failed to record snapshot of session `%s` on behalf of trigger `%s`: %s",
637 get_trigger_name(work_item
->trigger
),
638 lttng_strerror(-cmd_ret
));
639 lttng_action_increase_execution_failure_count(action
);
643 } catch (const lttng::sessiond::exceptions::session_not_found_error
& ex
) {
644 DBG_FMT("Failed to execution trigger action: {}, action=`{}`, trigger_name=`{}`, location='{}'",
647 get_action_name(action
),
648 get_trigger_name(work_item
->trigger
),
650 lttng_action_increase_execution_failure_count(action
);
656 static int action_executor_list_handler(struct action_executor
*executor
__attribute__((unused
)),
657 const struct action_work_item
*work_item
658 __attribute__((unused
)),
659 struct action_work_subitem
*item
__attribute__((unused
)))
661 ERR("Execution of a list action by the action executor should never occur");
665 static int action_executor_generic_handler(struct action_executor
*executor
,
666 const struct action_work_item
*work_item
,
667 struct action_work_subitem
*item
)
670 struct lttng_action
*action
= item
->action
;
671 const enum lttng_action_type action_type
= lttng_action_get_type(action
);
673 LTTNG_ASSERT(action_type
!= LTTNG_ACTION_TYPE_UNKNOWN
);
675 lttng_action_increase_execution_request_count(action
);
676 if (!lttng_action_should_execute(action
)) {
677 DBG("Policy prevented execution of action `%s` of trigger `%s` action work item %" PRIu64
,
678 get_action_name(action
),
679 get_trigger_name(work_item
->trigger
),
685 lttng_action_increase_execution_count(action
);
686 DBG("Executing action `%s` of trigger `%s` action work item %" PRIu64
,
687 get_action_name(action
),
688 get_trigger_name(work_item
->trigger
),
690 ret
= action_executors
[action_type
](executor
, work_item
, item
);
695 static int action_work_item_execute(struct action_executor
*executor
,
696 struct action_work_item
*work_item
)
701 DBG("Starting execution of action work item %" PRIu64
" of trigger `%s`",
703 get_trigger_name(work_item
->trigger
));
705 count
= lttng_dynamic_array_get_count(&work_item
->subitems
);
706 for (i
= 0; i
< count
; i
++) {
707 struct action_work_subitem
*item
;
709 item
= (action_work_subitem
*) lttng_dynamic_array_get_element(&work_item
->subitems
,
711 ret
= action_executor_generic_handler(executor
, work_item
, item
);
717 DBG("Completed execution of action work item %" PRIu64
" of trigger `%s`",
719 get_trigger_name(work_item
->trigger
));
723 static void action_work_item_destroy(struct action_work_item
*work_item
)
725 lttng_trigger_put(work_item
->trigger
);
726 lttng_evaluation_destroy(work_item
->evaluation
);
727 notification_client_list_put(work_item
->client_list
);
728 lttng_dynamic_array_reset(&work_item
->subitems
);
732 static void *action_executor_thread(void *_data
)
734 struct action_executor
*executor
= (action_executor
*) _data
;
736 LTTNG_ASSERT(executor
);
738 health_register(the_health_sessiond
, HEALTH_SESSIOND_TYPE_ACTION_EXECUTOR
);
740 rcu_register_thread();
743 DBG("Entering work execution loop");
744 pthread_mutex_lock(&executor
->work
.lock
);
745 while (!executor
->should_quit
) {
747 struct action_work_item
*work_item
;
749 health_code_update();
750 if (executor
->work
.pending_count
== 0) {
752 DBG("No work items enqueued, entering wait");
753 pthread_cond_wait(&executor
->work
.cond
, &executor
->work
.lock
);
754 DBG("Woke-up from wait");
759 /* Pop item from front of the list with work lock held. */
760 work_item
= cds_list_first_entry(
761 &executor
->work
.list
, struct action_work_item
, list_node
);
762 cds_list_del(&work_item
->list_node
);
763 executor
->work
.pending_count
--;
766 * Work can be performed without holding the work lock,
767 * allowing new items to be queued.
769 pthread_mutex_unlock(&executor
->work
.lock
);
771 /* Execute item only if a trigger is registered. */
772 lttng_trigger_lock(work_item
->trigger
);
773 if (!lttng_trigger_is_registered(work_item
->trigger
)) {
774 const char *trigger_name
= nullptr;
775 uid_t trigger_owner_uid
;
776 enum lttng_trigger_status trigger_status
;
778 trigger_name
= get_trigger_name(work_item
->trigger
);
781 lttng_trigger_get_owner_uid(work_item
->trigger
, &trigger_owner_uid
);
782 LTTNG_ASSERT(trigger_status
== LTTNG_TRIGGER_STATUS_OK
);
784 DBG("Work item skipped since the associated trigger is no longer registered: work item id = %" PRIu64
785 ", trigger name = `%s`, trigger owner uid = %d",
788 (int) trigger_owner_uid
);
793 ret
= action_work_item_execute(executor
, work_item
);
796 lttng_trigger_unlock(work_item
->trigger
);
797 action_work_item_destroy(work_item
);
803 health_code_update();
804 pthread_mutex_lock(&executor
->work
.lock
);
807 if (executor
->should_quit
) {
808 pthread_mutex_unlock(&executor
->work
.lock
);
810 DBG("Left work execution loop");
812 health_code_update();
814 rcu_thread_offline();
815 rcu_unregister_thread();
816 health_unregister(the_health_sessiond
);
821 static bool shutdown_action_executor_thread(void *_data
)
823 struct action_executor
*executor
= (action_executor
*) _data
;
825 pthread_mutex_lock(&executor
->work
.lock
);
826 executor
->should_quit
= true;
827 pthread_cond_signal(&executor
->work
.cond
);
828 pthread_mutex_unlock(&executor
->work
.lock
);
832 static void clean_up_action_executor_thread(void *_data
)
834 struct action_executor
*executor
= (action_executor
*) _data
;
836 LTTNG_ASSERT(cds_list_empty(&executor
->work
.list
));
838 pthread_mutex_destroy(&executor
->work
.lock
);
839 pthread_cond_destroy(&executor
->work
.cond
);
843 struct action_executor
*action_executor_create(struct notification_thread_handle
*handle
)
845 struct action_executor
*executor
= zmalloc
<action_executor
>();
851 CDS_INIT_LIST_HEAD(&executor
->work
.list
);
852 pthread_cond_init(&executor
->work
.cond
, nullptr);
853 pthread_mutex_init(&executor
->work
.lock
, nullptr);
854 executor
->notification_thread_handle
= handle
;
856 executor
->thread
= lttng_thread_create(THREAD_NAME
,
857 action_executor_thread
,
858 shutdown_action_executor_thread
,
859 clean_up_action_executor_thread
,
865 void action_executor_destroy(struct action_executor
*executor
)
867 struct action_work_item
*work_item
, *tmp
;
869 /* TODO Wait for work list to drain? */
870 lttng_thread_shutdown(executor
->thread
);
871 pthread_mutex_lock(&executor
->work
.lock
);
872 if (executor
->work
.pending_count
!= 0) {
874 " trigger action%s still queued for execution and will be discarded",
875 executor
->work
.pending_count
,
876 executor
->work
.pending_count
== 1 ? " is" : "s are");
879 cds_list_for_each_entry_safe (work_item
, tmp
, &executor
->work
.list
, list_node
) {
880 WARN("Discarding action work item %" PRIu64
" associated to trigger `%s`",
882 get_trigger_name(work_item
->trigger
));
883 cds_list_del(&work_item
->list_node
);
884 action_work_item_destroy(work_item
);
886 pthread_mutex_unlock(&executor
->work
.lock
);
887 lttng_thread_put(executor
->thread
);
890 /* RCU read-lock must be held by the caller. */
891 enum action_executor_status
892 action_executor_enqueue_trigger(struct action_executor
*executor
,
893 struct lttng_trigger
*trigger
,
894 struct lttng_evaluation
*evaluation
,
895 const struct lttng_credentials
*object_creds
,
896 struct notification_client_list
*client_list
)
899 enum action_executor_status executor_status
= ACTION_EXECUTOR_STATUS_OK
;
900 const uint64_t work_item_id
= executor
->next_work_item_id
++;
901 struct action_work_item
*work_item
;
904 LTTNG_ASSERT(trigger
);
905 ASSERT_RCU_READ_LOCKED();
907 pthread_mutex_lock(&executor
->work
.lock
);
908 /* Check for queue overflow. */
909 if (executor
->work
.pending_count
>= MAX_QUEUED_WORK_COUNT
) {
910 /* Most likely spammy, remove if it is the case. */
911 DBG("Refusing to enqueue action for trigger (overflow): trigger name = `%s`, work item id = %" PRIu64
,
912 get_trigger_name(trigger
),
914 executor_status
= ACTION_EXECUTOR_STATUS_OVERFLOW
;
918 work_item
= zmalloc
<action_work_item
>();
920 PERROR("Failed to allocate action executor work item: trigger name = `%s`",
921 get_trigger_name(trigger
));
922 executor_status
= ACTION_EXECUTOR_STATUS_ERROR
;
926 lttng_trigger_get(trigger
);
928 const bool reference_acquired
= notification_client_list_get(client_list
);
930 LTTNG_ASSERT(reference_acquired
);
933 work_item
->id
= work_item_id
;
934 work_item
->trigger
= trigger
;
936 /* Ownership transferred to the work item. */
937 work_item
->evaluation
= evaluation
;
938 evaluation
= nullptr;
940 work_item
->client_list
= client_list
;
941 work_item
->object_creds
.is_set
= !!object_creds
;
943 work_item
->object_creds
.value
= *object_creds
;
946 CDS_INIT_LIST_HEAD(&work_item
->list_node
);
948 /* Build the array of action work subitems for the passed trigger. */
949 lttng_dynamic_array_init(&work_item
->subitems
,
950 sizeof(struct action_work_subitem
),
951 action_work_subitem_destructor
);
953 ret
= populate_subitem_array_from_trigger(trigger
, &work_item
->subitems
);
955 ERR("Failed to populate work item sub items on behalf of trigger: trigger name = `%s`",
956 get_trigger_name(trigger
));
957 executor_status
= ACTION_EXECUTOR_STATUS_ERROR
;
961 cds_list_add_tail(&work_item
->list_node
, &executor
->work
.list
);
962 executor
->work
.pending_count
++;
963 DBG("Enqueued action for trigger: trigger name = `%s`, work item id = %" PRIu64
,
964 get_trigger_name(trigger
),
970 pthread_cond_signal(&executor
->work
.cond
);
973 pthread_mutex_unlock(&executor
->work
.lock
);
974 lttng_evaluation_destroy(evaluation
);
975 return executor_status
;
978 static int add_action_to_subitem_array(struct lttng_action
*action
,
979 struct lttng_dynamic_array
*subitems
)
982 enum lttng_action_type type
= lttng_action_get_type(action
);
983 const char *session_name
= nullptr;
984 enum lttng_action_status status
;
985 struct action_work_subitem subitem
= {
988 .session_id
= LTTNG_OPTIONAL_INIT_UNSET
,
992 LTTNG_ASSERT(action
);
993 LTTNG_ASSERT(subitems
);
995 if (type
== LTTNG_ACTION_TYPE_LIST
) {
996 for (auto inner_action
: lttng::ctl::action_list_view(action
)) {
997 LTTNG_ASSERT(inner_action
);
999 ret
= add_action_to_subitem_array(inner_action
, subitems
);
1006 * Go directly to the end since there is no need to add the
1007 * list action by itself to the subitems array.
1012 /* Gather execution context. */
1014 case LTTNG_ACTION_TYPE_NOTIFY
:
1016 case LTTNG_ACTION_TYPE_START_SESSION
:
1017 status
= lttng_action_start_session_get_session_name(action
, &session_name
);
1018 LTTNG_ASSERT(status
== LTTNG_ACTION_STATUS_OK
);
1020 case LTTNG_ACTION_TYPE_STOP_SESSION
:
1021 status
= lttng_action_stop_session_get_session_name(action
, &session_name
);
1022 LTTNG_ASSERT(status
== LTTNG_ACTION_STATUS_OK
);
1024 case LTTNG_ACTION_TYPE_ROTATE_SESSION
:
1025 status
= lttng_action_rotate_session_get_session_name(action
, &session_name
);
1026 LTTNG_ASSERT(status
== LTTNG_ACTION_STATUS_OK
);
1028 case LTTNG_ACTION_TYPE_SNAPSHOT_SESSION
:
1029 status
= lttng_action_snapshot_session_get_session_name(action
, &session_name
);
1030 LTTNG_ASSERT(status
== LTTNG_ACTION_STATUS_OK
);
1032 case LTTNG_ACTION_TYPE_LIST
:
1033 case LTTNG_ACTION_TYPE_UNKNOWN
:
1041 * Fetch the session execution context info as needed.
1042 * Note that we could decide to not add an action for which we know the
1043 * execution will not happen (i.e no session exists for that name). For
1044 * now we leave the decision to skip to the action executor for sake of
1045 * simplicity and consistency.
1047 if (session_name
!= nullptr) {
1048 uint64_t session_id
;
1051 * Instantaneous sampling of the session id if present.
1053 * This method is preferred over `sessiond_find_by_name` then
1054 * fetching the session'd id since `sessiond_find_by_name`
1055 * requires the session list lock to be taken.
1057 * Taking the session list lock can lead to a deadlock
1058 * between the action executor and the notification thread
1059 * (caller of add_action_to_subitem_array). It is okay if the
1060 * session state changes between the enqueuing time and the
1061 * execution time. The execution context is validated at
1064 if (sample_session_id_by_name(session_name
, &session_id
)) {
1065 LTTNG_OPTIONAL_SET(&subitem
.context
.session_id
, session_id
);
1069 /* Get a reference to the action. */
1070 lttng_action_get(action
);
1071 subitem
.action
= action
;
1073 ret
= lttng_dynamic_array_add_element(subitems
, &subitem
);
1075 ERR("Failed to add work subitem to the subitem array");
1076 lttng_action_put(action
);
1085 static int populate_subitem_array_from_trigger(struct lttng_trigger
*trigger
,
1086 struct lttng_dynamic_array
*subitems
)
1088 struct lttng_action
*action
;
1090 action
= lttng_trigger_get_action(trigger
);
1091 LTTNG_ASSERT(action
);
1093 return add_action_to_subitem_array(action
, subitems
);