src/bin/lttng-sessiond/action-executor.c

   1 /*
   2  * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #include "action-executor.h"
   9 #include "cmd.h"
  10 #include "health-sessiond.h"
  11 #include "lttng-sessiond.h"
  12 #include "notification-thread-internal.h"
  13 #include "session.h"
  14 #include "thread.h"
  15 #include <common/macros.h>
  16 #include <lttng/action/group.h>
  17 #include <lttng/action/notify-internal.h>
  18 #include <lttng/action/notify.h>
  19 #include <lttng/action/rotate-session.h>
  20 #include <lttng/action/snapshot-session.h>
  21 #include <lttng/action/start-session.h>
  22 #include <lttng/action/stop-session.h>
  23 #include <lttng/condition/evaluation.h>
  24 #include <lttng/condition/event-rule-internal.h>
  25 #include <lttng/lttng-error.h>
  26 #include <lttng/trigger/trigger-internal.h>
  27 #include <pthread.h>
  28 #include <stdbool.h>
  29 #include <stddef.h>
  30 #include <urcu/list.h>
  31
  32 #define THREAD_NAME "Action Executor"
  33 #define MAX_QUEUED_WORK_COUNT 8192
  34
  35 struct action_work_item {
  36         uint64_t id;
  37         struct lttng_trigger *trigger;
  38         struct notification_client_list *client_list;
  39         struct cds_list_head list_node;
  40         struct lttng_trigger_notification *trigger_notification;
  41 };
  42
  43 struct action_executor {
  44         struct lttng_thread *thread;
  45         struct notification_thread_handle *notification_thread_handle;
  46         struct {
  47                 uint64_t pending_count;
  48                 struct cds_list_head list;
  49                 pthread_cond_t cond;
  50                 pthread_mutex_t lock;
  51         } work;
  52         bool should_quit;
  53         uint64_t next_work_item_id;
  54 };
  55
  56 typedef int (*action_executor_handler)(struct action_executor *executor,
  57                 const struct action_work_item *,
  58                 const struct lttng_action *action);
  59
  60 static int action_executor_notify_handler(struct action_executor *executor,
  61                 const struct action_work_item *,
  62                 const struct lttng_action *);
  63 static int action_executor_start_session_handler(struct action_executor *executor,
  64                 const struct action_work_item *,
  65                 const struct lttng_action *);
  66 static int action_executor_stop_session_handler(struct action_executor *executor,
  67                 const struct action_work_item *,
  68                 const struct lttng_action *);
  69 static int action_executor_rotate_session_handler(struct action_executor *executor,
  70                 const struct action_work_item *,
  71                 const struct lttng_action *);
  72 static int action_executor_snapshot_session_handler(struct action_executor *executor,
  73                 const struct action_work_item *,
  74                 const struct lttng_action *);
  75 static int action_executor_group_handler(struct action_executor *executor,
  76                 const struct action_work_item *,
  77                 const struct lttng_action *);
  78 static int action_executor_generic_handler(struct action_executor *executor,
  79                 const struct action_work_item *,
  80                 const struct lttng_action *);
  81
  82 static const action_executor_handler action_executors[] = {
  83         [LTTNG_ACTION_TYPE_NOTIFY] = action_executor_notify_handler,
  84         [LTTNG_ACTION_TYPE_START_SESSION] = action_executor_start_session_handler,
  85         [LTTNG_ACTION_TYPE_STOP_SESSION] = action_executor_stop_session_handler,
  86         [LTTNG_ACTION_TYPE_ROTATE_SESSION] = action_executor_rotate_session_handler,
  87         [LTTNG_ACTION_TYPE_SNAPSHOT_SESSION] = action_executor_snapshot_session_handler,
  88         [LTTNG_ACTION_TYPE_GROUP] = action_executor_group_handler,
  89 };
  90
  91 static const char *get_action_name(const struct lttng_action *action)
  92 {
  93         const char *action_type_names[] = {
  94                 [LTTNG_ACTION_TYPE_NOTIFY] = "Notify",
  95                 [LTTNG_ACTION_TYPE_START_SESSION] = "Start session",
  96                 [LTTNG_ACTION_TYPE_STOP_SESSION] = "Stop session",
  97                 [LTTNG_ACTION_TYPE_ROTATE_SESSION] = "Rotate session",
  98                 [LTTNG_ACTION_TYPE_SNAPSHOT_SESSION] = "Snapshot session",
  99                 [LTTNG_ACTION_TYPE_GROUP] = "Group",
 100         };
 101
 102         return action_type_names[lttng_action_get_type(action)];
 103 }
 104
 105 static const char *get_trigger_name(const struct lttng_trigger *trigger)
 106 {
 107         const char *trigger_name;
 108         enum lttng_trigger_status trigger_status;
 109
 110         trigger_status = lttng_trigger_get_name(trigger, &trigger_name);
 111         assert(trigger_status == LTTNG_TRIGGER_STATUS_OK);
 112
 113         return trigger_name;
 114 }
 115
 116 static int client_handle_transmission_status(
 117                 struct notification_client *client,
 118                 enum client_transmission_status status,
 119                 void *user_data)
 120 {
 121         int ret = 0;
 122         struct action_executor *executor = user_data;
 123         bool update_communication = true;
 124
 125         ASSERT_LOCKED(client->lock);
 126
 127         switch (status) {
 128         case CLIENT_TRANSMISSION_STATUS_COMPLETE:
 129                 DBG("Successfully sent full notification to client, client_id = %" PRIu64,
 130                                 client->id);
 131                 update_communication = false;
 132                 break;
 133         case CLIENT_TRANSMISSION_STATUS_QUEUED:
 134                 DBG("Queued notification in client outgoing buffer, client_id = %" PRIu64,
 135                                 client->id);
 136                 break;
 137         case CLIENT_TRANSMISSION_STATUS_FAIL:
 138                 DBG("Communication error occurred while sending notification to client, client_id = %" PRIu64,
 139                                 client->id);
 140                 client->communication.active = false;
 141                 break;
 142         default:
 143                 ERR("Fatal error encoutered while sending notification to client, client_id = %" PRIu64,
 144                                 client->id);
 145                 client->communication.active = false;
 146                 ret = -1;
 147                 goto end;
 148         }
 149
 150         if (!update_communication) {
 151                 goto end;
 152         }
 153
 154         ret = notification_thread_client_communication_update(
 155                         executor->notification_thread_handle, client->id,
 156                         status);
 157 end:
 158         return ret;
 159 }
 160
 161 static int action_executor_notify_handler(struct action_executor *executor,
 162                 const struct action_work_item *work_item,
 163                 const struct lttng_action *action)
 164 {
 165         int ret = 0;
 166         struct lttng_evaluation *evaluation = NULL;
 167         struct lttng_trigger_notification *notification = work_item->trigger_notification;
 168         unsigned int capture_count = 0;
 169
 170         assert(work_item->client_list);
 171
 172         if (LTTNG_CONDITION_STATUS_OK !=
 173                         lttng_condition_event_rule_get_capture_descriptor_count(
 174                                 lttng_trigger_get_const_condition(work_item->trigger),
 175                                 &capture_count)) {
 176                 ERR("Get capture count");
 177                 ret = -1;
 178                 goto end;
 179         }
 180
 181         if (!notification->capture_buffer && capture_count != 0) {
 182                 ERR("Expected capture but capture buffer is null");
 183                 ret = -1;
 184                 goto end;
 185         }
 186
 187         evaluation = lttng_evaluation_event_rule_create(
 188                         container_of(lttng_trigger_get_const_condition(work_item->trigger),
 189                                         struct lttng_condition_event_rule,
 190                                         parent),
 191                         get_trigger_name(work_item->trigger),
 192                         notification->capture_buffer,
 193                         notification->capture_buf_size, false);
 194         if (!evaluation) {
 195                 ERR("Failed to create event rule hit evaluation");
 196                 ret = -1;
 197                 goto end;
 198         }
 199
 200         ret = notification_client_list_send_evaluation(work_item->client_list,
 201                         lttng_trigger_get_const_condition(work_item->trigger),
 202                         evaluation,
 203                         lttng_trigger_get_credentials(work_item->trigger), NULL,
 204                         client_handle_transmission_status, executor);
 205 end:
 206         lttng_evaluation_destroy(evaluation);
 207         return ret;
 208 }
 209
 210 static int action_executor_start_session_handler(struct action_executor *executor,
 211                 const struct action_work_item *work_item,
 212                 const struct lttng_action *action)
 213 {
 214         int ret = 0;
 215         const char *session_name;
 216         enum lttng_action_status action_status;
 217         struct ltt_session *session;
 218
 219         action_status = lttng_action_start_session_get_session_name(
 220                         action, &session_name);
 221         if (action_status != LTTNG_ACTION_STATUS_OK) {
 222                 ERR("Failed to get session name from \"%s\" action",
 223                                 get_action_name(action));
 224                 ret = -1;
 225                 goto end;
 226         }
 227
 228         session_lock_list();
 229         session = session_find_by_name(session_name);
 230         if (session) {
 231                 enum lttng_error_code cmd_ret;
 232
 233                 session_lock(session);
 234                 cmd_ret = cmd_start_trace(session);
 235                 session_unlock(session);
 236
 237                 switch (cmd_ret) {
 238                 case LTTNG_OK:
 239                         DBG("Successfully started session \"%s\" on behalf of trigger \"%s\"",
 240                                         session_name,
 241                                         get_trigger_name(work_item->trigger));
 242                         break;
 243                 case LTTNG_ERR_TRACE_ALREADY_STARTED:
 244                         DBG("Attempted to start session \"%s\" on behalf of trigger \"%s\" but it was already started",
 245                                         session_name,
 246                                         get_trigger_name(work_item->trigger));
 247                         break;
 248                 default:
 249                         WARN("Failed to start session \"%s\" on behalf of trigger \"%s\": %s",
 250                                         session_name,
 251                                         get_trigger_name(work_item->trigger),
 252                                         lttng_strerror(-cmd_ret));
 253                         break;
 254                 }
 255                 session_put(session);
 256         } else {
 257                 DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
 258                                 session_name, get_action_name(action),
 259                                 get_trigger_name(work_item->trigger));
 260         }
 261         session_unlock_list();
 262 end:
 263         return ret;
 264 }
 265
 266 static int action_executor_stop_session_handler(struct action_executor *executor,
 267                 const struct action_work_item *work_item,
 268                 const struct lttng_action *action)
 269 {
 270         int ret = 0;
 271         const char *session_name;
 272         enum lttng_action_status action_status;
 273         struct ltt_session *session;
 274
 275         action_status = lttng_action_stop_session_get_session_name(
 276                         action, &session_name);
 277         if (action_status != LTTNG_ACTION_STATUS_OK) {
 278                 ERR("Failed to get session name from \"%s\" action",
 279                                 get_action_name(action));
 280                 ret = -1;
 281                 goto end;
 282         }
 283
 284         session_lock_list();
 285         session = session_find_by_name(session_name);
 286         if (session) {
 287                 enum lttng_error_code cmd_ret;
 288
 289                 session_lock(session);
 290                 cmd_ret = cmd_stop_trace(session);
 291                 session_unlock(session);
 292
 293                 switch (cmd_ret) {
 294                 case LTTNG_OK:
 295                         DBG("Successfully stopped session \"%s\" on behalf of trigger \"%s\"",
 296                                         session_name,
 297                                         get_trigger_name(work_item->trigger));
 298                         break;
 299                 case LTTNG_ERR_TRACE_ALREADY_STOPPED:
 300                         DBG("Attempted to stop session \"%s\" on behalf of trigger \"%s\" but it was already stopped",
 301                                         session_name,
 302                                         get_trigger_name(work_item->trigger));
 303                         break;
 304                 default:
 305                         WARN("Failed to stop session \"%s\" on behalf of trigger \"%s\": %s",
 306                                         session_name,
 307                                         get_trigger_name(work_item->trigger),
 308                                         lttng_strerror(-cmd_ret));
 309                         break;
 310                 }
 311                 session_put(session);
 312         } else {
 313                 DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
 314                                 session_name, get_action_name(action),
 315                                 get_trigger_name(work_item->trigger));
 316         }
 317         session_unlock_list();
 318 end:
 319         return ret;
 320 }
 321
 322 static int action_executor_rotate_session_handler(struct action_executor *executor,
 323                 const struct action_work_item *work_item,
 324                 const struct lttng_action *action)
 325 {
 326         int ret = 0;
 327         const char *session_name;
 328         enum lttng_action_status action_status;
 329         struct ltt_session *session;
 330
 331         action_status = lttng_action_rotate_session_get_session_name(
 332                         action, &session_name);
 333         if (action_status != LTTNG_ACTION_STATUS_OK) {
 334                 ERR("Failed to get session name from \"%s\" action",
 335                                 get_action_name(action));
 336                 ret = -1;
 337                 goto end;
 338         }
 339
 340         session_lock_list();
 341         session = session_find_by_name(session_name);
 342         if (session) {
 343                 enum lttng_error_code cmd_ret;
 344
 345                 session_lock(session);
 346                 cmd_ret = cmd_rotate_session(session, NULL, false,
 347                                 LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED);
 348                 session_unlock(session);
 349
 350                 switch (cmd_ret) {
 351                 case LTTNG_OK:
 352                         DBG("Successfully started rotation of session \"%s\" on behalf of trigger \"%s\"",
 353                                         session_name,
 354                                         get_trigger_name(work_item->trigger));
 355                         break;
 356                 case LTTNG_ERR_ROTATION_PENDING:
 357                         DBG("Attempted to start a rotation of session \"%s\" on behalf of trigger \"%s\" but a rotation is already ongoing",
 358                                         session_name,
 359                                         get_trigger_name(work_item->trigger));
 360                         break;
 361                 case LTTNG_ERR_ROTATION_MULTIPLE_AFTER_STOP:
 362                 case LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR:
 363                         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",
 364                                         session_name,
 365                                         get_trigger_name(work_item->trigger));
 366                         break;
 367                 default:
 368                         WARN("Failed to start a rotation of session \"%s\" on behalf of trigger \"%s\": %s",
 369                                         session_name,
 370                                         get_trigger_name(work_item->trigger),
 371                                         lttng_strerror(-cmd_ret));
 372                         break;
 373                 }
 374                 session_put(session);
 375         } else {
 376                 DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
 377                                 session_name, get_action_name(action),
 378                                 get_trigger_name(work_item->trigger));
 379         }
 380         session_unlock_list();
 381 end:
 382         return ret;
 383 }
 384
 385 static int action_executor_snapshot_session_handler(struct action_executor *executor,
 386                 const struct action_work_item *work_item,
 387                 const struct lttng_action *action)
 388 {
 389         int ret = 0;
 390         const char *session_name;
 391         enum lttng_action_status action_status;
 392         struct ltt_session *session;
 393         const struct lttng_snapshot_output default_snapshot_output = {
 394                 .max_size = UINT64_MAX,
 395         };
 396         const struct lttng_snapshot_output *snapshot_output =
 397                         &default_snapshot_output;
 398
 399         action_status = lttng_action_snapshot_session_get_session_name(
 400                         action, &session_name);
 401         if (action_status != LTTNG_ACTION_STATUS_OK) {
 402                 ERR("Failed to get session name from \"%s\" action",
 403                                 get_action_name(action));
 404                 ret = -1;
 405                 goto end;
 406         }
 407
 408         action_status = lttng_action_snapshot_session_get_output_const(
 409                         action, &snapshot_output);
 410         if (action_status != LTTNG_ACTION_STATUS_OK &&
 411                         action_status != LTTNG_ACTION_STATUS_UNSET) {
 412                 ERR("Failed to get output from \"%s\" action",
 413                                 get_action_name(action));
 414                 ret = -1;
 415                 goto end;
 416         }
 417
 418         session_lock_list();
 419         session = session_find_by_name(session_name);
 420         if (session) {
 421                 enum lttng_error_code cmd_ret;
 422
 423                 session_lock(session);
 424                 cmd_ret = cmd_snapshot_record(session, snapshot_output, 0);
 425                 session_unlock(session);
 426
 427                 switch (cmd_ret) {
 428                 case LTTNG_OK:
 429                         DBG("Successfully recorded snapshot of session \"%s\" on behalf of trigger \"%s\"",
 430                                         session_name,
 431                                         get_trigger_name(work_item->trigger));
 432                         break;
 433                 default:
 434                         WARN("Failed to record snapshot of session \"%s\" on behalf of trigger \"%s\": %s",
 435                                         session_name,
 436                                         get_trigger_name(work_item->trigger),
 437                                         lttng_strerror(-cmd_ret));
 438                         break;
 439                 }
 440                 session_put(session);
 441         } else {
 442                 DBG("Failed to find session \"%s\" by name while executing \"%s\" action of trigger \"%s\"",
 443                                 session_name, get_action_name(action),
 444                                 get_trigger_name(work_item->trigger));
 445         }
 446         session_unlock_list();
 447 end:
 448         return ret;
 449 }
 450
 451 static int action_executor_group_handler(struct action_executor *executor,
 452                 const struct action_work_item *work_item,
 453                 const struct lttng_action *action_group)
 454 {
 455         int ret = 0;
 456         unsigned int i, count;
 457         enum lttng_action_status action_status;
 458
 459         action_status = lttng_action_group_get_count(action_group, &count);
 460         if (action_status != LTTNG_ACTION_STATUS_OK) {
 461                 /* Fatal error. */
 462                 ERR("Failed to get count of action in action group");
 463                 ret = -1;
 464                 goto end;
 465         }
 466
 467         DBG("Action group has %u action%s", count, count != 1 ? "s" : "");
 468         for (i = 0; i < count; i++) {
 469                 const struct lttng_action *action =
 470                                 lttng_action_group_get_at_index_const(
 471                                                 action_group, i);
 472
 473                 ret = action_executor_generic_handler(
 474                                 executor, work_item, action);
 475                 if (ret) {
 476                         ERR("Stopping the execution of the action group of trigger \"%s\" following a fatal error",
 477                                         get_trigger_name(work_item->trigger));
 478                         goto end;
 479                 }
 480         }
 481 end:
 482         return ret;
 483 }
 484
 485 static int action_executor_generic_handler(struct action_executor *executor,
 486                 const struct action_work_item *work_item,
 487                 const struct lttng_action *action)
 488 {
 489         DBG("Executing action \"%s\" of trigger \"%s\" action work item %" PRIu64,
 490                         get_action_name(action),
 491                         get_trigger_name(work_item->trigger),
 492                         work_item->id);
 493
 494         return action_executors[lttng_action_get_type(action)](
 495                         executor, work_item, action);
 496 }
 497
 498 static int action_work_item_execute(struct action_executor *executor,
 499                 struct action_work_item *work_item)
 500 {
 501         int ret;
 502         const struct lttng_action *action =
 503                         lttng_trigger_get_const_action(work_item->trigger);
 504
 505         DBG("Starting execution of action work item %" PRIu64 " of trigger \"%s\"",
 506                         work_item->id, get_trigger_name(work_item->trigger));
 507         ret = action_executor_generic_handler(executor, work_item, action);
 508         DBG("Completed execution of action work item %" PRIu64 " of trigger \"%s\"",
 509                         work_item->id, get_trigger_name(work_item->trigger));
 510         return ret;
 511 }
 512
 513 static void action_work_item_destroy(struct action_work_item *work_item)
 514 {
 515         lttng_trigger_put(work_item->trigger);
 516         notification_client_list_put(work_item->client_list);
 517         lttng_trigger_notification_destroy(work_item->trigger_notification);
 518         free(work_item);
 519 }
 520
 521 static void *action_executor_thread(void *_data)
 522 {
 523         struct action_executor *executor = _data;
 524
 525         assert(executor);
 526
 527         health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ACTION_EXECUTOR);
 528
 529         rcu_register_thread();
 530         rcu_thread_online();
 531
 532         DBG("Entering work execution loop");
 533         pthread_mutex_lock(&executor->work.lock);
 534         while (!executor->should_quit) {
 535                 int ret;
 536                 struct action_work_item *work_item;
 537
 538                 health_code_update();
 539                 if (executor->work.pending_count == 0) {
 540                         health_poll_entry();
 541                         DBG("No work items enqueued, entering wait");
 542                         pthread_cond_wait(&executor->work.cond,
 543                                         &executor->work.lock);
 544                         DBG("Woke-up from wait");
 545                         health_poll_exit();
 546                         continue;
 547                 }
 548
 549                 /* Pop item from front of the list with work lock held. */
 550                 work_item = cds_list_first_entry(&executor->work.list,
 551                                 struct action_work_item, list_node);
 552                 cds_list_del(&work_item->list_node);
 553                 executor->work.pending_count--;
 554
 555                 /*
 556                  * Work can be performed without holding the work lock,
 557                  * allowing new items to be queued.
 558                  */
 559                 pthread_mutex_unlock(&executor->work.lock);
 560                 ret = action_work_item_execute(executor, work_item);
 561                 action_work_item_destroy(work_item);
 562                 if (ret) {
 563                         /* Fatal error. */
 564                         break;
 565                 }
 566                 health_code_update();
 567                 pthread_mutex_lock(&executor->work.lock);
 568         }
 569         pthread_mutex_unlock(&executor->work.lock);
 570         DBG("Left work execution loop");
 571
 572         health_code_update();
 573
 574         rcu_thread_offline();
 575         rcu_unregister_thread();
 576         health_unregister(health_sessiond);
 577
 578         return NULL;
 579 }
 580
 581 static bool shutdown_action_executor_thread(void *_data)
 582 {
 583         struct action_executor *executor = _data;
 584
 585         /* TODO. */
 586         executor->should_quit = true;
 587         pthread_cond_signal(&executor->work.cond);
 588         return true;
 589 }
 590
 591 static void clean_up_action_executor_thread(void *_data)
 592 {
 593         struct action_executor *executor = _data;
 594
 595         assert(cds_list_empty(&executor->work.list));
 596
 597         pthread_mutex_destroy(&executor->work.lock);
 598         pthread_cond_destroy(&executor->work.cond);
 599         free(executor);
 600 }
 601
 602 struct action_executor *action_executor_create(
 603                 struct notification_thread_handle *handle)
 604 {
 605         struct action_executor *executor = zmalloc(sizeof(*executor));
 606
 607         if (!executor) {
 608                 goto end;
 609         }
 610
 611         CDS_INIT_LIST_HEAD(&executor->work.list);
 612         pthread_cond_init(&executor->work.cond, NULL);
 613         pthread_mutex_init(&executor->work.lock, NULL);
 614         executor->notification_thread_handle = handle;
 615
 616         executor->thread = lttng_thread_create(THREAD_NAME,
 617                         action_executor_thread, shutdown_action_executor_thread,
 618                         clean_up_action_executor_thread, executor);
 619 end:
 620         return executor;
 621 }
 622
 623 void action_executor_destroy(struct action_executor *executor)
 624 {
 625         struct action_work_item *work_item, *tmp;
 626
 627         /* TODO Wait for work list to drain? */
 628         lttng_thread_shutdown(executor->thread);
 629         pthread_mutex_lock(&executor->work.lock);
 630         if (executor->work.pending_count != 0) {
 631                 WARN("%" PRIu64
 632                         " trigger action%s still queued for execution and will be discarded",
 633                                 executor->work.pending_count,
 634                                 executor->work.pending_count == 1 ? " is" :
 635                                                                     "s are");
 636         }
 637
 638         cds_list_for_each_entry_safe (
 639                         work_item, tmp, &executor->work.list, list_node) {
 640                 WARN("Discarding action work item %" PRIu64
 641                                 " associated to trigger \"%s\"",
 642                                 work_item->id, get_trigger_name(work_item->trigger));
 643                 cds_list_del(&work_item->list_node);
 644                 action_work_item_destroy(work_item);
 645         }
 646         pthread_mutex_unlock(&executor->work.lock);
 647         lttng_thread_put(executor->thread);
 648 }
 649
 650 /* RCU read-lock must be held by the caller. */
 651 enum action_executor_status action_executor_enqueue(
 652                 struct action_executor *executor,
 653                 struct lttng_trigger *trigger,
 654                 struct notification_client_list *client_list,
 655                 struct lttng_trigger_notification *trigger_notification)
 656 {
 657         enum action_executor_status executor_status = ACTION_EXECUTOR_STATUS_OK;
 658         const uint64_t work_item_id = executor->next_work_item_id++;
 659         struct action_work_item *work_item;
 660         bool signal = false;
 661
 662         pthread_mutex_lock(&executor->work.lock);
 663         /* Check for queue overflow. */
 664         if (executor->work.pending_count >= MAX_QUEUED_WORK_COUNT) {
 665                 /* Most likely spammy, remove if it is the case. */
 666                 DBG("Refusing to enqueue action for trigger \"%s\" as work item %" PRIu64
 667                         " (overflow)",
 668                                 get_trigger_name(trigger), work_item_id);
 669                 executor_status = ACTION_EXECUTOR_STATUS_OVERFLOW;
 670                 goto error_unlock;
 671         }
 672
 673         work_item = zmalloc(sizeof(*work_item));
 674         if (!work_item) {
 675                 PERROR("Failed to allocate action executor work item on behalf of trigger \"%s\"",
 676                                 get_trigger_name(trigger));
 677                 executor_status = ACTION_EXECUTOR_STATUS_ERROR;
 678                 goto error_unlock;
 679         }
 680
 681         lttng_trigger_get(trigger);
 682         if (client_list) {
 683                 const bool reference_acquired =
 684                                 notification_client_list_get(client_list);
 685
 686                 assert(reference_acquired);
 687         }
 688
 689         *work_item = (typeof(*work_item)){
 690                         .id = work_item_id,
 691                         .trigger = trigger,
 692                         .client_list = client_list,
 693                         .list_node = CDS_LIST_HEAD_INIT(work_item->list_node),
 694                         .trigger_notification = trigger_notification,
 695         };
 696         cds_list_add_tail(&work_item->list_node, &executor->work.list);
 697         executor->work.pending_count++;
 698         DBG("Enqueued action for trigger \"%s\" as work item %" PRIu64,
 699                         get_trigger_name(trigger), work_item_id);
 700         signal = true;
 701
 702         /*
 703          * Note:
 704          * Ownership of the lttng_trigger_notification object passed to the work
 705          * item object incidentally to the executor list.
 706          * Caller is responsible for freeing in case of error.
 707          */
 708
 709 error_unlock:
 710         pthread_mutex_unlock(&executor->work.lock);
 711         if (signal) {
 712                 pthread_cond_signal(&executor->work.cond);
 713         }
 714         return executor_status;
 715 }