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 <common/optional.h>
  17 #include <lttng/action/action-internal.h>
  18 #include <lttng/action/group.h>
  19 #include <lttng/action/notify.h>
  20 #include <lttng/action/rotate-session.h>
  21 #include <lttng/action/snapshot-session.h>
  22 #include <lttng/action/start-session.h>
  23 #include <lttng/action/stop-session.h>
  24 #include <lttng/condition/evaluation.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 lttng_evaluation *evaluation;
  39         struct notification_client_list *client_list;
  40         LTTNG_OPTIONAL(struct lttng_credentials) object_creds;
  41         struct cds_list_head list_node;
  42 };
  43
  44 struct action_executor {
  45         struct lttng_thread *thread;
  46         struct notification_thread_handle *notification_thread_handle;
  47         struct {
  48                 uint64_t pending_count;
  49                 struct cds_list_head list;
  50                 pthread_cond_t cond;
  51                 pthread_mutex_t lock;
  52         } work;
  53         bool should_quit;
  54         uint64_t next_work_item_id;
  55 };
  56
  57 /*
  58  * Only return non-zero on a fatal error that should shut down the action
  59  * executor.
  60  */
  61 typedef int (*action_executor_handler)(struct action_executor *executor,
  62                 const struct action_work_item *,
  63                 const struct lttng_action *action);
  64
  65 static int action_executor_notify_handler(struct action_executor *executor,
  66                 const struct action_work_item *,
  67                 const struct lttng_action *);
  68 static int action_executor_start_session_handler(struct action_executor *executor,
  69                 const struct action_work_item *,
  70                 const struct lttng_action *);
  71 static int action_executor_stop_session_handler(struct action_executor *executor,
  72                 const struct action_work_item *,
  73                 const struct lttng_action *);
  74 static int action_executor_rotate_session_handler(struct action_executor *executor,
  75                 const struct action_work_item *,
  76                 const struct lttng_action *);
  77 static int action_executor_snapshot_session_handler(struct action_executor *executor,
  78                 const struct action_work_item *,
  79                 const struct lttng_action *);
  80 static int action_executor_group_handler(struct action_executor *executor,
  81                 const struct action_work_item *,
  82                 const struct lttng_action *);
  83 static int action_executor_generic_handler(struct action_executor *executor,
  84                 const struct action_work_item *,
  85                 const struct lttng_action *);
  86
  87 static const action_executor_handler action_executors[] = {
  88         [LTTNG_ACTION_TYPE_NOTIFY] = action_executor_notify_handler,
  89         [LTTNG_ACTION_TYPE_START_SESSION] = action_executor_start_session_handler,
  90         [LTTNG_ACTION_TYPE_STOP_SESSION] = action_executor_stop_session_handler,
  91         [LTTNG_ACTION_TYPE_ROTATE_SESSION] = action_executor_rotate_session_handler,
  92         [LTTNG_ACTION_TYPE_SNAPSHOT_SESSION] = action_executor_snapshot_session_handler,
  93         [LTTNG_ACTION_TYPE_GROUP] = action_executor_group_handler,
  94 };
  95
  96 static const char *action_type_names[] = {
  97         [LTTNG_ACTION_TYPE_NOTIFY] = "Notify",
  98         [LTTNG_ACTION_TYPE_START_SESSION] = "Start session",
  99         [LTTNG_ACTION_TYPE_STOP_SESSION] = "Stop session",
 100         [LTTNG_ACTION_TYPE_ROTATE_SESSION] = "Rotate session",
 101         [LTTNG_ACTION_TYPE_SNAPSHOT_SESSION] = "Snapshot session",
 102         [LTTNG_ACTION_TYPE_GROUP] = "Group",
 103 };
 104
 105 static const char *get_action_name(const struct lttng_action *action)
 106 {
 107         return action_type_names[lttng_action_get_type_const(action)];
 108 }
 109
 110 /* Check if this trigger allowed to interect with a given session. */
 111 static bool is_trigger_allowed_for_session(const struct lttng_trigger *trigger,
 112                 struct ltt_session *session)
 113 {
 114         bool is_allowed = false;
 115         const struct lttng_credentials session_creds = {
 116                 .uid = session->uid,
 117                 .gid = session->gid,
 118         };
 119         /* Can never be NULL. */
 120         const struct lttng_credentials *trigger_creds =
 121                         lttng_trigger_get_credentials(trigger);
 122
 123         is_allowed = (trigger_creds->uid == session_creds.uid) ||
 124                         (trigger_creds->uid == 0);
 125         if (!is_allowed) {
 126                 WARN("Trigger is not allowed to interact with session `%s`: session uid = %ld, session gid = %ld, trigger uid = %ld, trigger gid = %ld",
 127                                 session->name,
 128                                 (long int) session->uid,
 129                                 (long int) session->gid,
 130                                 (long int) trigger_creds->uid,
 131                                 (long int) trigger_creds->gid);
 132         }
 133
 134         return is_allowed;
 135 }
 136
 137 static int client_handle_transmission_status(
 138                 struct notification_client *client,
 139                 enum client_transmission_status status,
 140                 void *user_data)
 141 {
 142         int ret = 0;
 143         struct action_executor *executor = user_data;
 144         bool update_communication = true;
 145
 146         ASSERT_LOCKED(client->lock);
 147
 148         switch (status) {
 149         case CLIENT_TRANSMISSION_STATUS_COMPLETE:
 150                 DBG("Successfully sent full notification to client, client_id = %" PRIu64,
 151                                 client->id);
 152                 update_communication = false;
 153                 break;
 154         case CLIENT_TRANSMISSION_STATUS_QUEUED:
 155                 DBG("Queued notification in client outgoing buffer, client_id = %" PRIu64,
 156                                 client->id);
 157                 break;
 158         case CLIENT_TRANSMISSION_STATUS_FAIL:
 159                 DBG("Communication error occurred while sending notification to client, client_id = %" PRIu64,
 160                                 client->id);
 161                 client->communication.active = false;
 162                 break;
 163         default:
 164                 ERR("Fatal error encoutered while sending notification to client, client_id = %" PRIu64,
 165                                 client->id);
 166                 client->communication.active = false;
 167                 ret = -1;
 168                 goto end;
 169         }
 170
 171         if (!update_communication) {
 172                 goto end;
 173         }
 174
 175         ret = notification_thread_client_communication_update(
 176                         executor->notification_thread_handle, client->id,
 177                         status);
 178 end:
 179         return ret;
 180 }
 181
 182 static int action_executor_notify_handler(struct action_executor *executor,
 183                 const struct action_work_item *work_item,
 184                 const struct lttng_action *action)
 185 {
 186         return notification_client_list_send_evaluation(work_item->client_list,
 187                         lttng_trigger_get_const_condition(work_item->trigger),
 188                         work_item->evaluation,
 189                         lttng_trigger_get_credentials(work_item->trigger),
 190                         LTTNG_OPTIONAL_GET_PTR(work_item->object_creds),
 191                         client_handle_transmission_status,
 192                         executor);
 193 }
 194
 195 static int action_executor_start_session_handler(struct action_executor *executor,
 196                 const struct action_work_item *work_item,
 197                 const struct lttng_action *action)
 198 {
 199         int ret = 0;
 200         const char *session_name;
 201         enum lttng_action_status action_status;
 202         struct ltt_session *session;
 203         enum lttng_error_code cmd_ret;
 204
 205         action_status = lttng_action_start_session_get_session_name(
 206                         action, &session_name);
 207         if (action_status != LTTNG_ACTION_STATUS_OK) {
 208                 ERR("Failed to get session name from `%s` action",
 209                                 get_action_name(action));
 210                 ret = -1;
 211                 goto end;
 212         }
 213
 214         session_lock_list();
 215         session = session_find_by_name(session_name);
 216         if (!session) {
 217                 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
 218                                 session_name, get_action_name(action),
 219                     work_item->trigger);
 220                 goto error_unlock_list;
 221         }
 222
 223         session_lock(session);
 224         if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
 225                 goto error_dispose_session;
 226         }
 227
 228         cmd_ret = cmd_start_trace(session);
 229         switch (cmd_ret) {
 230         case LTTNG_OK:
 231                 DBG("Successfully started session `%s` on behalf of trigger `%p`",
 232                                 session_name, work_item->trigger);
 233                 break;
 234         case LTTNG_ERR_TRACE_ALREADY_STARTED:
 235                 DBG("Attempted to start session `%s` on behalf of trigger `%p` but it was already started",
 236                                 session_name, work_item->trigger);
 237                 break;
 238         default:
 239                 WARN("Failed to start session `%s` on behalf of trigger `%p`: %s",
 240                                 session_name, work_item->trigger,
 241                                 lttng_strerror(-cmd_ret));
 242                 break;
 243         }
 244
 245 error_dispose_session:
 246         session_unlock(session);
 247         session_put(session);
 248 error_unlock_list:
 249         session_unlock_list();
 250 end:
 251         return ret;
 252 }
 253
 254 static int action_executor_stop_session_handler(struct action_executor *executor,
 255                 const struct action_work_item *work_item,
 256                 const struct lttng_action *action)
 257 {
 258         int ret = 0;
 259         const char *session_name;
 260         enum lttng_action_status action_status;
 261         struct ltt_session *session;
 262         enum lttng_error_code cmd_ret;
 263
 264         action_status = lttng_action_stop_session_get_session_name(
 265                         action, &session_name);
 266         if (action_status != LTTNG_ACTION_STATUS_OK) {
 267                 ERR("Failed to get session name from `%s` action",
 268                                 get_action_name(action));
 269                 ret = -1;
 270                 goto end;
 271         }
 272
 273         session_lock_list();
 274         session = session_find_by_name(session_name);
 275         if (!session) {
 276                 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
 277                                 session_name, get_action_name(action),
 278                     work_item->trigger);
 279                 goto error_unlock_list;
 280         }
 281
 282         session_lock(session);
 283         if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
 284                 goto error_dispose_session;
 285         }
 286
 287         cmd_ret = cmd_stop_trace(session);
 288         switch (cmd_ret) {
 289         case LTTNG_OK:
 290                 DBG("Successfully stopped session `%s` on behalf of trigger `%p`",
 291                                 session_name, work_item->trigger);
 292                 break;
 293         case LTTNG_ERR_TRACE_ALREADY_STOPPED:
 294                 DBG("Attempted to stop session `%s` on behalf of trigger `%p` but it was already stopped",
 295                                 session_name, work_item->trigger);
 296                 break;
 297         default:
 298                 WARN("Failed to stop session `%s` on behalf of trigger `%p`: %s",
 299                                 session_name, work_item->trigger,
 300                                 lttng_strerror(-cmd_ret));
 301                 break;
 302         }
 303
 304 error_dispose_session:
 305         session_unlock(session);
 306         session_put(session);
 307 error_unlock_list:
 308         session_unlock_list();
 309 end:
 310         return ret;
 311 }
 312
 313 static int action_executor_rotate_session_handler(struct action_executor *executor,
 314                 const struct action_work_item *work_item,
 315                 const struct lttng_action *action)
 316 {
 317         int ret = 0;
 318         const char *session_name;
 319         enum lttng_action_status action_status;
 320         struct ltt_session *session;
 321         enum lttng_error_code cmd_ret;
 322
 323         action_status = lttng_action_rotate_session_get_session_name(
 324                         action, &session_name);
 325         if (action_status != LTTNG_ACTION_STATUS_OK) {
 326                 ERR("Failed to get session name from `%s` action",
 327                                 get_action_name(action));
 328                 ret = -1;
 329                 goto end;
 330         }
 331
 332         session_lock_list();
 333         session = session_find_by_name(session_name);
 334         if (!session) {
 335                 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
 336                                 session_name, get_action_name(action),
 337                     work_item->trigger);
 338                 goto error_unlock_list;
 339         }
 340
 341         session_lock(session);
 342         if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
 343                 goto error_dispose_session;
 344         }
 345
 346         cmd_ret = cmd_rotate_session(session, NULL, false,
 347                         LTTNG_TRACE_CHUNK_COMMAND_TYPE_MOVE_TO_COMPLETED);
 348         switch (cmd_ret) {
 349         case LTTNG_OK:
 350                 DBG("Successfully started rotation of session `%s` on behalf of trigger `%p`",
 351                                 session_name, work_item->trigger);
 352                 break;
 353         case LTTNG_ERR_ROTATION_PENDING:
 354                 DBG("Attempted to start a rotation of session `%s` on behalf of trigger `%p` but a rotation is already ongoing",
 355                                 session_name, work_item->trigger);
 356                 break;
 357         case LTTNG_ERR_ROTATION_MULTIPLE_AFTER_STOP:
 358         case LTTNG_ERR_ROTATION_AFTER_STOP_CLEAR:
 359                 DBG("Attempted to start a rotation of session `%s` on behalf of trigger `%p` but a rotation has already been completed since the last stop or clear",
 360                                 session_name, work_item->trigger);
 361                 break;
 362         default:
 363                 WARN("Failed to start a rotation of session `%s` on behalf of trigger `%p`: %s",
 364                                 session_name, work_item->trigger,
 365                                 lttng_strerror(-cmd_ret));
 366                 break;
 367         }
 368
 369 error_dispose_session:
 370         session_unlock(session);
 371         session_put(session);
 372 error_unlock_list:
 373         session_unlock_list();
 374 end:
 375         return ret;
 376 }
 377
 378 static int action_executor_snapshot_session_handler(struct action_executor *executor,
 379                 const struct action_work_item *work_item,
 380                 const struct lttng_action *action)
 381 {
 382         int ret = 0;
 383         const char *session_name;
 384         enum lttng_action_status action_status;
 385         struct ltt_session *session;
 386         const struct lttng_snapshot_output default_snapshot_output = {
 387                 .max_size = UINT64_MAX,
 388         };
 389         const struct lttng_snapshot_output *snapshot_output =
 390                         &default_snapshot_output;
 391         enum lttng_error_code cmd_ret;
 392
 393         action_status = lttng_action_snapshot_session_get_session_name(
 394                         action, &session_name);
 395         if (action_status != LTTNG_ACTION_STATUS_OK) {
 396                 ERR("Failed to get session name from `%s` action",
 397                                 get_action_name(action));
 398                 ret = -1;
 399                 goto end;
 400         }
 401
 402         action_status = lttng_action_snapshot_session_get_output(
 403                         action, &snapshot_output);
 404         if (action_status != LTTNG_ACTION_STATUS_OK &&
 405                         action_status != LTTNG_ACTION_STATUS_UNSET) {
 406                 ERR("Failed to get output from `%s` action",
 407                                 get_action_name(action));
 408                 ret = -1;
 409                 goto end;
 410         }
 411
 412         session_lock_list();
 413         session = session_find_by_name(session_name);
 414         if (!session) {
 415                 DBG("Failed to find session `%s` by name while executing `%s` action of trigger `%p`",
 416                                 session_name, get_action_name(action),
 417                     work_item->trigger);
 418                 goto error_unlock_list;
 419         }
 420
 421
 422         session_lock(session);
 423         if (!is_trigger_allowed_for_session(work_item->trigger, session)) {
 424                 goto error_dispose_session;
 425         }
 426
 427         cmd_ret = cmd_snapshot_record(session, snapshot_output, 0);
 428         switch (cmd_ret) {
 429         case LTTNG_OK:
 430                 DBG("Successfully recorded snapshot of session `%s` on behalf of trigger `%p`",
 431                                 session_name, work_item->trigger);
 432                 break;
 433         default:
 434                 WARN("Failed to record snapshot of session `%s` on behalf of trigger `%p`: %s",
 435                                 session_name, work_item->trigger,
 436                                 lttng_strerror(-cmd_ret));
 437                 break;
 438         }
 439
 440 error_dispose_session:
 441         session_unlock(session);
 442         session_put(session);
 443 error_unlock_list:
 444         session_unlock_list();
 445 end:
 446         return ret;
 447 }
 448
 449 static int action_executor_group_handler(struct action_executor *executor,
 450                 const struct action_work_item *work_item,
 451                 const struct lttng_action *action_group)
 452 {
 453         int ret = 0;
 454         unsigned int i, count;
 455         enum lttng_action_status action_status;
 456
 457         action_status = lttng_action_group_get_count(action_group, &count);
 458         if (action_status != LTTNG_ACTION_STATUS_OK) {
 459                 /* Fatal error. */
 460                 ERR("Failed to get count of action in action group");
 461                 ret = -1;
 462                 goto end;
 463         }
 464
 465         DBG("Action group has %u action%s", count, count != 1 ? "s" : "");
 466         for (i = 0; i < count; i++) {
 467                 const struct lttng_action *action =
 468                                 lttng_action_group_get_at_index(
 469                                                 action_group, i);
 470
 471                 ret = action_executor_generic_handler(
 472                                 executor, work_item, action);
 473                 if (ret) {
 474                         ERR("Stopping the execution of the action group of trigger `%p` following a fatal error",
 475                                         work_item->trigger);
 476                         goto end;
 477                 }
 478         }
 479 end:
 480         return ret;
 481 }
 482
 483 static int action_executor_generic_handler(struct action_executor *executor,
 484                 const struct action_work_item *work_item,
 485                 const struct lttng_action *action)
 486 {
 487         DBG("Executing action `%s` of trigger `%p` action work item %" PRIu64,
 488                         get_action_name(action),
 489                         work_item->trigger,
 490                         work_item->id);
 491
 492         return action_executors[lttng_action_get_type_const(action)](
 493                         executor, work_item, action);
 494 }
 495
 496 static int action_work_item_execute(struct action_executor *executor,
 497                 struct action_work_item *work_item)
 498 {
 499         int ret;
 500         const struct lttng_action *action =
 501                         lttng_trigger_get_const_action(work_item->trigger);
 502
 503         DBG("Starting execution of action work item %" PRIu64 " of trigger `%p`",
 504                         work_item->id, work_item->trigger);
 505         ret = action_executor_generic_handler(executor, work_item, action);
 506         DBG("Completed execution of action work item %" PRIu64 " of trigger `%p`",
 507                         work_item->id, work_item->trigger);
 508         return ret;
 509 }
 510
 511 static void action_work_item_destroy(struct action_work_item *work_item)
 512 {
 513         lttng_trigger_put(work_item->trigger);
 514         lttng_evaluation_destroy(work_item->evaluation);
 515         notification_client_list_put(work_item->client_list);
 516         free(work_item);
 517 }
 518
 519 static void *action_executor_thread(void *_data)
 520 {
 521         struct action_executor *executor = _data;
 522
 523         assert(executor);
 524
 525         health_register(health_sessiond, HEALTH_SESSIOND_TYPE_ACTION_EXECUTOR);
 526
 527         rcu_register_thread();
 528         rcu_thread_online();
 529
 530         DBG("Entering work execution loop");
 531         pthread_mutex_lock(&executor->work.lock);
 532         while (!executor->should_quit) {
 533                 int ret;
 534                 struct action_work_item *work_item;
 535
 536                 health_code_update();
 537                 if (executor->work.pending_count == 0) {
 538                         health_poll_entry();
 539                         DBG("No work items enqueued, entering wait");
 540                         pthread_cond_wait(&executor->work.cond,
 541                                         &executor->work.lock);
 542                         DBG("Woke-up from wait");
 543                         health_poll_exit();
 544                         continue;
 545                 }
 546
 547                 /* Pop item from front of the listwith work lock held. */
 548                 work_item = cds_list_first_entry(&executor->work.list,
 549                                 struct action_work_item, list_node);
 550                 cds_list_del(&work_item->list_node);
 551                 executor->work.pending_count--;
 552
 553                 /*
 554                  * Work can be performed without holding the work lock,
 555                  * allowing new items to be queued.
 556                  */
 557                 pthread_mutex_unlock(&executor->work.lock);
 558                 ret = action_work_item_execute(executor, work_item);
 559                 action_work_item_destroy(work_item);
 560                 if (ret) {
 561                         /* Fatal error. */
 562                         break;
 563                 }
 564
 565                 health_code_update();
 566                 pthread_mutex_lock(&executor->work.lock);
 567         }
 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         executor->should_quit = true;
 586         pthread_cond_signal(&executor->work.cond);
 587         return true;
 588 }
 589
 590 static void clean_up_action_executor_thread(void *_data)
 591 {
 592         struct action_executor *executor = _data;
 593
 594         assert(cds_list_empty(&executor->work.list));
 595
 596         pthread_mutex_destroy(&executor->work.lock);
 597         pthread_cond_destroy(&executor->work.cond);
 598         free(executor);
 599 }
 600
 601 struct action_executor *action_executor_create(
 602                 struct notification_thread_handle *handle)
 603 {
 604         struct action_executor *executor = zmalloc(sizeof(*executor));
 605
 606         if (!executor) {
 607                 goto end;
 608         }
 609
 610         CDS_INIT_LIST_HEAD(&executor->work.list);
 611         pthread_cond_init(&executor->work.cond, NULL);
 612         pthread_mutex_init(&executor->work.lock, NULL);
 613         executor->notification_thread_handle = handle;
 614
 615         executor->thread = lttng_thread_create(THREAD_NAME,
 616                         action_executor_thread, shutdown_action_executor_thread,
 617                         clean_up_action_executor_thread, executor);
 618 end:
 619         return executor;
 620 }
 621
 622 void action_executor_destroy(struct action_executor *executor)
 623 {
 624         struct action_work_item *work_item, *tmp;
 625
 626         /* TODO Wait for work list to drain? */
 627         lttng_thread_shutdown(executor->thread);
 628         pthread_mutex_lock(&executor->work.lock);
 629         if (executor->work.pending_count != 0) {
 630                 WARN("%" PRIu64
 631                         " trigger action%s still queued for execution and will be discarded",
 632                                 executor->work.pending_count,
 633                                 executor->work.pending_count == 1 ? " is" :
 634                                                                     "s are");
 635         }
 636
 637         cds_list_for_each_entry_safe (
 638                         work_item, tmp, &executor->work.list, list_node) {
 639                 WARN("Discarding action work item %" PRIu64
 640                                 " associated to trigger `%p`",
 641                                 work_item->id, work_item->trigger);
 642                 cds_list_del(&work_item->list_node);
 643                 action_work_item_destroy(work_item);
 644         }
 645         pthread_mutex_unlock(&executor->work.lock);
 646         lttng_thread_put(executor->thread);
 647 }
 648
 649 /* RCU read-lock must be held by the caller. */
 650 enum action_executor_status action_executor_enqueue(
 651                 struct action_executor *executor,
 652                 struct lttng_trigger *trigger,
 653                 struct lttng_evaluation *evaluation,
 654                 const struct lttng_credentials *object_creds,
 655                 struct notification_client_list *client_list)
 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 `%p` as work item %" PRIu64
 667                     " (overflow)",
 668                                 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 `%p`",
 676                                 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                         /* Ownership transferred to the work item. */
 693                         .evaluation = evaluation,
 694                         .object_creds = {
 695                                 .is_set = !!object_creds,
 696                                 .value = object_creds ? *object_creds :
 697                                         (typeof(work_item->object_creds.value)) {},
 698                         },
 699                         .client_list = client_list,
 700                         .list_node = CDS_LIST_HEAD_INIT(work_item->list_node),
 701         };
 702
 703         evaluation = NULL;
 704         cds_list_add_tail(&work_item->list_node, &executor->work.list);
 705         executor->work.pending_count++;
 706         DBG("Enqueued action for trigger `%p` as work item %" PRIu64,
 707                         trigger, work_item_id);
 708         signal = true;
 709
 710 error_unlock:
 711         pthread_mutex_unlock(&executor->work.lock);
 712         if (signal) {
 713                 pthread_cond_signal(&executor->work.cond);
 714         }
 715
 716         lttng_evaluation_destroy(evaluation);
 717         return executor_status;
 718 }