src/bin/lttng-sessiond/event.cpp

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   3  * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include "agent.hpp"
  11 #include "channel.hpp"
  12 #include "event.hpp"
  13 #include "kernel.hpp"
  14 #include "lttng-sessiond.hpp"
  15 #include "lttng-ust-ctl.hpp"
  16 #include "lttng-ust-error.hpp"
  17 #include "trace-kernel.hpp"
  18 #include "trace-ust.hpp"
  19 #include "ust-app.hpp"
  20 #include "utils.hpp"
  21
  22 #include <common/bytecode/bytecode.hpp>
  23 #include <common/compat/errno.hpp>
  24 #include <common/context.hpp>
  25 #include <common/error.hpp>
  26 #include <common/filter.hpp>
  27 #include <common/sessiond-comm/sessiond-comm.hpp>
  28 #include <common/urcu.hpp>
  29
  30 #include <lttng/condition/condition.h>
  31 #include <lttng/condition/event-rule-matches.h>
  32 #include <lttng/event-rule/event-rule-internal.hpp>
  33 #include <lttng/event-rule/event-rule.h>
  34 #include <lttng/lttng.h>
  35
  36 #include <string.h>
  37 #include <urcu/list.h>
  38
  39 /*
  40  * Add unique UST event based on the event name, filter bytecode and loglevel.
  41  */
  42 static void add_unique_ust_event(struct lttng_ht *ht, struct ltt_ust_event *event)
  43 {
  44         struct cds_lfht_node *node_ptr;
  45         struct ltt_ust_ht_key key;
  46
  47         LTTNG_ASSERT(ht);
  48         LTTNG_ASSERT(ht->ht);
  49         LTTNG_ASSERT(event);
  50
  51         key.name = event->attr.name;
  52         key.filter = (struct lttng_bytecode *) event->filter;
  53         key.loglevel_type = (lttng_ust_abi_loglevel_type) event->attr.loglevel_type;
  54         key.loglevel_value = event->attr.loglevel;
  55         key.exclusion = event->exclusion;
  56
  57         node_ptr = cds_lfht_add_unique(ht->ht,
  58                                        ht->hash_fct(event->node.key, lttng_ht_seed),
  59                                        trace_ust_ht_match_event,
  60                                        &key,
  61                                        &event->node.node);
  62         LTTNG_ASSERT(node_ptr == &event->node.node);
  63 }
  64
  65 /*
  66  * Disable kernel tracepoint events for a channel from the kernel session of
  67  * a specified event_name and event type.
  68  * On type LTTNG_EVENT_ALL all events with event_name are disabled.
  69  * If event_name is NULL all events of the specified type are disabled.
  70  */
  71 int event_kernel_disable_event(struct ltt_kernel_channel *kchan,
  72                                const char *event_name,
  73                                enum lttng_event_type type)
  74 {
  75         int ret, error = 0, found = 0;
  76         struct ltt_kernel_event *kevent;
  77
  78         LTTNG_ASSERT(kchan);
  79
  80         /* For each event in the kernel session */
  81         cds_list_for_each_entry (kevent, &kchan->events_list.head, list) {
  82                 if (type != LTTNG_EVENT_ALL && kevent->type != type)
  83                         continue;
  84                 if (event_name != nullptr && strcmp(event_name, kevent->event->name) != 0) {
  85                         continue;
  86                 }
  87                 found++;
  88                 ret = kernel_disable_event(kevent);
  89                 if (ret < 0) {
  90                         error = 1;
  91                         continue;
  92                 }
  93         }
  94         DBG("Disable kernel event: found %d events with name: %s and type: %d",
  95             found,
  96             event_name ? event_name : "NULL",
  97             type);
  98
  99         if (event_name != nullptr && !found) {
 100                 ret = LTTNG_ERR_NO_EVENT;
 101         } else {
 102                 ret = error ? LTTNG_ERR_KERN_DISABLE_FAIL : LTTNG_OK;
 103         }
 104
 105         return ret;
 106 }
 107
 108 /*
 109  * Enable kernel tracepoint event for a channel from the kernel session.
 110  * We own filter_expression and filter.
 111  */
 112 int event_kernel_enable_event(struct ltt_kernel_channel *kchan,
 113                               struct lttng_event *event,
 114                               char *filter_expression,
 115                               struct lttng_bytecode *filter)
 116 {
 117         int ret;
 118         struct ltt_kernel_event *kevent;
 119
 120         LTTNG_ASSERT(kchan);
 121         LTTNG_ASSERT(event);
 122
 123         kevent = trace_kernel_find_event(event->name, kchan, event->type, filter);
 124         if (kevent == nullptr) {
 125                 ret = kernel_create_event(event, kchan, filter_expression, filter);
 126                 /* We have passed ownership */
 127                 filter_expression = nullptr;
 128                 filter = nullptr;
 129                 if (ret) {
 130                         goto end;
 131                 }
 132         } else if (!kevent->enabled) {
 133                 ret = kernel_enable_event(kevent);
 134                 if (ret < 0) {
 135                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 136                         goto end;
 137                 }
 138         } else {
 139                 /* At this point, the event is considered enabled */
 140                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 141                 goto end;
 142         }
 143
 144         ret = LTTNG_OK;
 145 end:
 146         free(filter_expression);
 147         free(filter);
 148         return ret;
 149 }
 150
 151 /*
 152  * ============================
 153  * UST : The Ultimate Frontier!
 154  * ============================
 155  */
 156
 157 /*
 158  * Enable UST tracepoint event for a channel from a UST session.
 159  * We own filter_expression, filter, and exclusion.
 160  */
 161 int event_ust_enable_tracepoint(struct ltt_ust_session *usess,
 162                                 struct ltt_ust_channel *uchan,
 163                                 struct lttng_event *event,
 164                                 char *filter_expression,
 165                                 struct lttng_bytecode *filter,
 166                                 struct lttng_event_exclusion *exclusion,
 167                                 bool internal_event)
 168 {
 169         int ret = LTTNG_OK, to_create = 0;
 170         struct ltt_ust_event *uevent;
 171
 172         LTTNG_ASSERT(usess);
 173         LTTNG_ASSERT(uchan);
 174         LTTNG_ASSERT(event);
 175
 176         const lttng::urcu::read_lock_guard read_lock;
 177
 178         uevent = trace_ust_find_event(uchan->events,
 179                                       event->name,
 180                                       filter,
 181                                       (enum lttng_ust_abi_loglevel_type) event->loglevel_type,
 182                                       event->loglevel,
 183                                       exclusion);
 184         if (!uevent) {
 185                 ret = trace_ust_create_event(
 186                         event, filter_expression, filter, exclusion, internal_event, &uevent);
 187                 /* We have passed ownership */
 188                 filter_expression = nullptr;
 189                 filter = nullptr;
 190                 exclusion = nullptr;
 191                 if (ret != LTTNG_OK) {
 192                         goto end;
 193                 }
 194
 195                 /* Valid to set it after the goto error since uevent is still NULL */
 196                 to_create = 1;
 197         }
 198
 199         if (uevent->enabled) {
 200                 /* It's already enabled so everything is OK */
 201                 LTTNG_ASSERT(!to_create);
 202                 ret = LTTNG_ERR_UST_EVENT_ENABLED;
 203                 goto end;
 204         }
 205
 206         uevent->enabled = true;
 207         if (to_create) {
 208                 /* Add ltt ust event to channel */
 209                 add_unique_ust_event(uchan->events, uevent);
 210         }
 211
 212         if (!usess->active) {
 213                 goto end;
 214         }
 215
 216         if (to_create) {
 217                 /* Create event on all UST registered apps for session */
 218                 ret = ust_app_create_event_glb(usess, uchan, uevent);
 219         } else {
 220                 /* Enable event on all UST registered apps for session */
 221                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 222         }
 223
 224         if (ret < 0) {
 225                 if (ret == -LTTNG_UST_ERR_EXIST) {
 226                         ret = LTTNG_ERR_UST_EVENT_EXIST;
 227                 } else {
 228                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 229                 }
 230                 goto end;
 231         }
 232
 233         DBG("Event UST %s %s in channel %s",
 234             uevent->attr.name,
 235             to_create ? "created" : "enabled",
 236             uchan->name);
 237
 238         ret = LTTNG_OK;
 239
 240 end:
 241         free(filter_expression);
 242         free(filter);
 243         free(exclusion);
 244         return ret;
 245 }
 246
 247 /*
 248  * Disable UST tracepoint of a channel from a UST session.
 249  */
 250 int event_ust_disable_tracepoint(struct ltt_ust_session *usess,
 251                                  struct ltt_ust_channel *uchan,
 252                                  const char *event_name)
 253 {
 254         int ret;
 255         struct ltt_ust_event *uevent;
 256         struct lttng_ht_node_str *node;
 257         struct lttng_ht_iter iter;
 258         struct lttng_ht *ht;
 259
 260         LTTNG_ASSERT(usess);
 261         LTTNG_ASSERT(uchan);
 262         LTTNG_ASSERT(event_name);
 263
 264         ht = uchan->events;
 265
 266         const lttng::urcu::read_lock_guard read_lock;
 267
 268         /*
 269          * We use a custom lookup since we need the iterator for the next_duplicate
 270          * call in the do while loop below.
 271          */
 272         cds_lfht_lookup(ht->ht,
 273                         ht->hash_fct((void *) event_name, lttng_ht_seed),
 274                         trace_ust_ht_match_event_by_name,
 275                         event_name,
 276                         &iter.iter);
 277         node = lttng_ht_iter_get_node<lttng_ht_node_str>(&iter);
 278         if (node == nullptr) {
 279                 DBG2("Trace UST event NOT found by name %s", event_name);
 280                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 281                 goto error;
 282         }
 283
 284         do {
 285                 uevent = lttng::utils::container_of(node, &ltt_ust_event::node);
 286                 LTTNG_ASSERT(uevent);
 287
 288                 if (!uevent->enabled) {
 289                         /* It's already disabled so everything is OK */
 290                         goto next;
 291                 }
 292                 uevent->enabled = false;
 293                 DBG2("Event UST %s disabled in channel %s", uevent->attr.name, uchan->name);
 294
 295                 if (!usess->active) {
 296                         goto next;
 297                 }
 298                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 299                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 300                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 301                         goto error;
 302                 }
 303         next:
 304                 /* Get next duplicate event by name. */
 305                 cds_lfht_next_duplicate(
 306                         ht->ht, trace_ust_ht_match_event_by_name, event_name, &iter.iter);
 307                 node = lttng_ht_iter_get_node<lttng_ht_node_str>(&iter);
 308         } while (node);
 309
 310         ret = LTTNG_OK;
 311
 312 error:
 313         return ret;
 314 }
 315
 316 /*
 317  * Disable all UST tracepoints for a channel from a UST session.
 318  */
 319 int event_ust_disable_all_tracepoints(struct ltt_ust_session *usess, struct ltt_ust_channel *uchan)
 320 {
 321         int ret, i, size, error = 0;
 322         struct lttng_event *events = nullptr;
 323
 324         LTTNG_ASSERT(usess);
 325         LTTNG_ASSERT(uchan);
 326
 327         /* Disabling existing events */
 328         for (auto *uevent :
 329              lttng::urcu::lfht_iteration_adapter<ltt_ust_event,
 330                                                  decltype(ltt_ust_event::node),
 331                                                  &ltt_ust_event::node>(*uchan->events->ht)) {
 332                 if (uevent->enabled) {
 333                         ret = event_ust_disable_tracepoint(usess, uchan, uevent->attr.name);
 334                         if (ret < 0) {
 335                                 error = LTTNG_ERR_UST_DISABLE_FAIL;
 336                                 continue;
 337                         }
 338                 }
 339         }
 340
 341         /* Get all UST available events */
 342         size = ust_app_list_events(&events);
 343         if (size < 0) {
 344                 ret = LTTNG_ERR_UST_LIST_FAIL;
 345                 goto error;
 346         }
 347
 348         for (i = 0; i < size; i++) {
 349                 ret = event_ust_disable_tracepoint(usess, uchan, events[i].name);
 350                 if (ret < 0) {
 351                         /* Continue to disable the rest... */
 352                         error = LTTNG_ERR_UST_DISABLE_FAIL;
 353                         continue;
 354                 }
 355         }
 356
 357         ret = error ? error : LTTNG_OK;
 358 error:
 359         free(events);
 360         return ret;
 361 }
 362
 363 static void agent_enable_all(struct agent *agt)
 364 {
 365         for (auto *aevent :
 366              lttng::urcu::lfht_iteration_adapter<agent_event,
 367                                                  decltype(agent_event::node),
 368                                                  &agent_event::node>(*agt->events->ht)) {
 369                 aevent->enabled_count++;
 370         }
 371 }
 372
 373 /*
 374  * Enable all agent event for a given UST session.
 375  *
 376  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 377  */
 378 int event_agent_enable_all(struct ltt_ust_session *usess,
 379                            struct agent *agt,
 380                            struct lttng_event *event,
 381                            struct lttng_bytecode *filter,
 382                            char *filter_expression)
 383 {
 384         int ret;
 385
 386         LTTNG_ASSERT(usess);
 387
 388         DBG("Event agent enabling ALL events for session %" PRIu64, usess->id);
 389
 390         /* Enable event on agent application through TCP socket. */
 391         ret = event_agent_enable(usess, agt, event, filter, filter_expression);
 392         if (ret != LTTNG_OK) {
 393                 goto error;
 394         }
 395
 396         agent_enable_all(agt);
 397
 398         ret = LTTNG_OK;
 399
 400 error:
 401         return ret;
 402 }
 403
 404 /*
 405  * Check if this event's filter requires the activation of application contexts
 406  * and enable them in the agent.
 407  * TODO: bytecode iterator does not support non-legacy application
 408  * contexts yet. Not an issue for now, since they are not generated by
 409  * the lttng-ctl library.
 410  */
 411 static int add_filter_app_ctx(struct lttng_bytecode *bytecode,
 412                               const char *filter_expression,
 413                               struct agent *agt)
 414 {
 415         int ret = LTTNG_OK;
 416         char *provider_name = nullptr, *ctx_name = nullptr;
 417         struct bytecode_symbol_iterator *it = bytecode_symbol_iterator_create(bytecode);
 418
 419         if (!it) {
 420                 ret = LTTNG_ERR_NOMEM;
 421                 goto end;
 422         }
 423
 424         do {
 425                 struct lttng_event_context ctx;
 426                 const char *symbol_name = bytecode_symbol_iterator_get_name(it);
 427
 428                 if (parse_application_context(symbol_name, &provider_name, &ctx_name)) {
 429                         /* Not an application context. */
 430                         continue;
 431                 }
 432
 433                 ctx.ctx = LTTNG_EVENT_CONTEXT_APP_CONTEXT;
 434                 ctx.u.app_ctx.provider_name = provider_name;
 435                 ctx.u.app_ctx.ctx_name = ctx_name;
 436
 437                 /* Recognized an application context. */
 438                 DBG("Enabling event with filter expression \"%s\" requires enabling the %s:%s application context.",
 439                     filter_expression,
 440                     provider_name,
 441                     ctx_name);
 442
 443                 ret = agent_add_context(&ctx, agt);
 444                 if (ret != LTTNG_OK) {
 445                         ERR("Failed to add application context %s:%s.", provider_name, ctx_name);
 446                         goto end;
 447                 }
 448
 449                 ret = agent_enable_context(&ctx, agt->domain);
 450                 if (ret != LTTNG_OK) {
 451                         ERR("Failed to enable application context %s:%s.", provider_name, ctx_name);
 452                         goto end;
 453                 }
 454
 455                 free(provider_name);
 456                 free(ctx_name);
 457                 provider_name = ctx_name = nullptr;
 458         } while (bytecode_symbol_iterator_next(it) == 0);
 459 end:
 460         free(provider_name);
 461         free(ctx_name);
 462         bytecode_symbol_iterator_destroy(it);
 463         return ret;
 464 }
 465
 466 static int agent_enable(struct agent *agt,
 467                         struct lttng_event *event,
 468                         struct lttng_bytecode *filter,
 469                         char *filter_expression)
 470 {
 471         int ret, created = 0;
 472         struct agent_event *aevent;
 473
 474         LTTNG_ASSERT(event);
 475         LTTNG_ASSERT(agt);
 476
 477         const lttng::urcu::read_lock_guard read_lock;
 478         aevent = agent_find_event(
 479                 event->name, event->loglevel_type, event->loglevel, filter_expression, agt);
 480         if (!aevent) {
 481                 aevent = agent_create_event(event->name,
 482                                             event->loglevel_type,
 483                                             event->loglevel,
 484                                             filter,
 485                                             filter_expression);
 486                 if (!aevent) {
 487                         ret = LTTNG_ERR_NOMEM;
 488                         goto error;
 489                 }
 490                 filter = nullptr;
 491                 filter_expression = nullptr;
 492                 created = 1;
 493                 LTTNG_ASSERT(!AGENT_EVENT_IS_ENABLED(aevent));
 494         }
 495
 496         if (created && aevent->filter) {
 497                 ret = add_filter_app_ctx(aevent->filter, aevent->filter_expression, agt);
 498                 if (ret != LTTNG_OK) {
 499                         goto error;
 500                 }
 501         }
 502
 503         /* Already enabled? */
 504         if (AGENT_EVENT_IS_ENABLED(aevent)) {
 505                 ret = LTTNG_OK;
 506                 goto end;
 507         }
 508
 509         ret = agent_enable_event(aevent, agt->domain);
 510         if (ret != LTTNG_OK) {
 511                 goto error;
 512         }
 513
 514         /* If the event was created prior to the enable, add it to the domain. */
 515         if (created) {
 516                 agent_add_event(aevent, agt);
 517         }
 518
 519         ret = LTTNG_OK;
 520         goto end;
 521
 522 error:
 523         if (created) {
 524                 agent_destroy_event(aevent);
 525         }
 526 end:
 527         free(filter);
 528         free(filter_expression);
 529         return ret;
 530 }
 531
 532 /*
 533  * Enable a single agent event for a given UST session.
 534  *
 535  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 536  */
 537 int event_agent_enable(struct ltt_ust_session *usess,
 538                        struct agent *agt,
 539                        struct lttng_event *event,
 540                        struct lttng_bytecode *filter,
 541                        char *filter_expression)
 542 {
 543         LTTNG_ASSERT(usess);
 544         LTTNG_ASSERT(event);
 545         LTTNG_ASSERT(agt);
 546
 547         DBG("Enabling agent event: event pattern = '%s', session id = %" PRIu64
 548             ", loglevel type = %d, loglevel = %d, filter expression = '%s'",
 549             event->name,
 550             usess->id,
 551             event->loglevel_type,
 552             event->loglevel,
 553             filter_expression ? filter_expression : "(none)");
 554
 555         return agent_enable(agt, event, filter, filter_expression);
 556 }
 557
 558 /*
 559  * Enable a single agent event for a trigger.
 560  *
 561  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 562  */
 563 int trigger_agent_enable(const struct lttng_trigger *trigger, struct agent *agt)
 564 {
 565         int ret;
 566         enum lttng_condition_status c_status;
 567         enum lttng_trigger_status t_status;
 568         enum lttng_domain_type d_type;
 569         const struct lttng_condition *condition;
 570         const struct lttng_event_rule *rule;
 571         const char *filter_expression;
 572         char *filter_expression_copy = nullptr;
 573         const struct lttng_bytecode *filter_bytecode;
 574         struct lttng_bytecode *filter_bytecode_copy = nullptr;
 575         struct lttng_event *event = nullptr;
 576         uid_t trigger_owner_uid = 0;
 577         const char *trigger_name;
 578
 579         LTTNG_ASSERT(trigger);
 580         LTTNG_ASSERT(agt);
 581
 582         t_status = lttng_trigger_get_name(trigger, &trigger_name);
 583         if (t_status != LTTNG_TRIGGER_STATUS_OK) {
 584                 trigger_name = "(anonymous)";
 585         }
 586
 587         t_status = lttng_trigger_get_owner_uid(trigger, &trigger_owner_uid);
 588         LTTNG_ASSERT(t_status == LTTNG_TRIGGER_STATUS_OK);
 589
 590         condition = lttng_trigger_get_const_condition(trigger);
 591
 592         LTTNG_ASSERT(lttng_condition_get_type(condition) ==
 593                      LTTNG_CONDITION_TYPE_EVENT_RULE_MATCHES);
 594
 595         c_status = lttng_condition_event_rule_matches_get_rule(condition, &rule);
 596         LTTNG_ASSERT(c_status == LTTNG_CONDITION_STATUS_OK);
 597
 598         switch (lttng_event_rule_get_type(rule)) {
 599         case LTTNG_EVENT_RULE_TYPE_JUL_LOGGING:
 600         case LTTNG_EVENT_RULE_TYPE_LOG4J_LOGGING:
 601         case LTTNG_EVENT_RULE_TYPE_LOG4J2_LOGGING:
 602         case LTTNG_EVENT_RULE_TYPE_PYTHON_LOGGING:
 603                 break;
 604         default:
 605                 abort();
 606                 break;
 607         }
 608
 609         d_type = lttng_event_rule_get_domain_type(rule);
 610         LTTNG_ASSERT(d_type == agt->domain);
 611
 612         event = lttng_event_rule_generate_lttng_event(rule);
 613         if (!event) {
 614                 ret = LTTNG_ERR_NOMEM;
 615                 goto end;
 616         }
 617
 618         /* Get the internal filter expression and bytecode. */
 619         filter_expression = lttng_event_rule_get_filter(rule);
 620         if (filter_expression) {
 621                 filter_expression_copy = strdup(filter_expression);
 622                 if (!filter_expression_copy) {
 623                         ret = LTTNG_ERR_NOMEM;
 624                         goto end;
 625                 }
 626
 627                 /* Get the filter bytecode */
 628                 filter_bytecode = lttng_event_rule_get_filter_bytecode(rule);
 629                 if (filter_bytecode) {
 630                         filter_bytecode_copy = lttng_bytecode_copy(filter_bytecode);
 631                         if (!filter_bytecode_copy) {
 632                                 ret = LTTNG_ERR_NOMEM;
 633                                 goto end;
 634                         }
 635                 }
 636         }
 637
 638         DBG("Enabling agent event from trigger: trigger name = '%s', trigger owner uid = %d, token = %" PRIu64,
 639             trigger_name,
 640             trigger_owner_uid,
 641             lttng_trigger_get_tracer_token(trigger));
 642
 643         ret = agent_enable(agt, event, filter_bytecode_copy, filter_expression_copy);
 644         /* Ownership was passed even in case of error. */
 645         filter_expression_copy = nullptr;
 646         filter_bytecode_copy = nullptr;
 647
 648 end:
 649         free(filter_expression_copy);
 650         free(filter_bytecode_copy);
 651         free(event);
 652         return ret;
 653 }
 654
 655 /*
 656  * Return the default event name associated with the provided UST domain. Return
 657  * NULL on error.
 658  */
 659 const char *event_get_default_agent_ust_name(enum lttng_domain_type domain)
 660 {
 661         const char *default_event_name = nullptr;
 662
 663         switch (domain) {
 664         case LTTNG_DOMAIN_LOG4J:
 665                 default_event_name = DEFAULT_LOG4J_EVENT_NAME;
 666                 break;
 667         case LTTNG_DOMAIN_LOG4J2:
 668                 default_event_name = DEFAULT_LOG4J2_EVENT_NAME;
 669                 break;
 670         case LTTNG_DOMAIN_JUL:
 671                 default_event_name = DEFAULT_JUL_EVENT_NAME;
 672                 break;
 673         case LTTNG_DOMAIN_PYTHON:
 674                 default_event_name = DEFAULT_PYTHON_EVENT_NAME;
 675                 break;
 676         default:
 677                 abort();
 678         }
 679
 680         return default_event_name;
 681 }
 682
 683 static int trigger_agent_disable_one(const struct lttng_trigger *trigger,
 684                                      struct agent *agt,
 685                                      struct agent_event *aevent)
 686
 687 {
 688         int ret;
 689
 690         LTTNG_ASSERT(agt);
 691         LTTNG_ASSERT(trigger);
 692         LTTNG_ASSERT(aevent);
 693
 694         /*
 695          * Actual ust event un-registration happens on the trigger
 696          * un-registration at that point.
 697          */
 698
 699         DBG("Event agent disabling %s (loglevel type %d, loglevel value %d) for trigger %" PRIu64,
 700             aevent->name,
 701             aevent->loglevel_type,
 702             aevent->loglevel_value,
 703             lttng_trigger_get_tracer_token(trigger));
 704
 705         /* Already disabled? */
 706         if (!AGENT_EVENT_IS_ENABLED(aevent)) {
 707                 goto end;
 708         }
 709
 710         ret = agent_disable_event(aevent, agt->domain);
 711         if (ret != LTTNG_OK) {
 712                 goto error;
 713         }
 714
 715 end:
 716         return LTTNG_OK;
 717
 718 error:
 719         return ret;
 720 }
 721
 722 /*
 723  * Disable a given agent event for a given UST session.
 724  *
 725  * Must be called with the RCU read lock held.
 726  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 727  */
 728 static int event_agent_disable_one(struct ltt_ust_session *usess,
 729                                    struct agent *agt,
 730                                    struct agent_event *aevent)
 731 {
 732         int ret;
 733         struct ltt_ust_event *uevent = nullptr;
 734         struct ltt_ust_channel *uchan = nullptr;
 735         const char *ust_event_name, *ust_channel_name;
 736
 737         LTTNG_ASSERT(agt);
 738         LTTNG_ASSERT(usess);
 739         LTTNG_ASSERT(aevent);
 740
 741         DBG("Event agent disabling %s (loglevel type %d, loglevel value %d) for session %" PRIu64,
 742             aevent->name,
 743             aevent->loglevel_type,
 744             aevent->loglevel_value,
 745             usess->id);
 746
 747         /* Already disabled? */
 748         if (!AGENT_EVENT_IS_ENABLED(aevent)) {
 749                 goto end;
 750         }
 751
 752         if (agt->domain == LTTNG_DOMAIN_JUL) {
 753                 ust_channel_name = DEFAULT_JUL_CHANNEL_NAME;
 754         } else if (agt->domain == LTTNG_DOMAIN_LOG4J) {
 755                 ust_channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
 756         } else if (agt->domain == LTTNG_DOMAIN_LOG4J2) {
 757                 ust_channel_name = DEFAULT_LOG4J2_CHANNEL_NAME;
 758         } else if (agt->domain == LTTNG_DOMAIN_PYTHON) {
 759                 ust_channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
 760         } else {
 761                 ret = LTTNG_ERR_INVALID;
 762                 goto error;
 763         }
 764
 765         /*
 766          * Disable it on the UST side. First get the channel reference then find
 767          * the event and finally disable it.
 768          */
 769         uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 770                                                (char *) ust_channel_name);
 771         if (!uchan) {
 772                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 773                 goto error;
 774         }
 775
 776         ust_event_name = event_get_default_agent_ust_name(agt->domain);
 777         if (!ust_event_name) {
 778                 ret = LTTNG_ERR_FATAL;
 779                 goto error;
 780         }
 781
 782         /*
 783          * Agent UST event has its loglevel type forced to
 784          * LTTNG_UST_LOGLEVEL_ALL. The actual loglevel type/value filtering
 785          * happens thanks to an UST filter. The following -1 is actually
 786          * ignored since the type is LTTNG_UST_LOGLEVEL_ALL.
 787          */
 788         uevent = trace_ust_find_event(uchan->events,
 789                                       (char *) ust_event_name,
 790                                       aevent->filter,
 791                                       LTTNG_UST_ABI_LOGLEVEL_ALL,
 792                                       -1,
 793                                       nullptr);
 794         /* If the agent event exists, it must be available on the UST side. */
 795         LTTNG_ASSERT(uevent);
 796
 797         if (usess->active) {
 798                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 799                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 800                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 801                         goto error;
 802                 }
 803         }
 804
 805         /*
 806          * Flag event that it's disabled so the shadow copy on the ust app side
 807          * will disable it if an application shows up.
 808          */
 809         uevent->enabled = false;
 810
 811         ret = agent_disable_event(aevent, agt->domain);
 812         if (ret != LTTNG_OK) {
 813                 goto error;
 814         }
 815
 816 end:
 817         return LTTNG_OK;
 818
 819 error:
 820         return ret;
 821 }
 822
 823 /*
 824  * Disable agent event matching a given trigger.
 825  *
 826  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 827  */
 828 int trigger_agent_disable(const struct lttng_trigger *trigger, struct agent *agt)
 829 {
 830         int ret = LTTNG_OK;
 831         struct agent_event *aevent;
 832
 833         LTTNG_ASSERT(trigger);
 834         LTTNG_ASSERT(agt);
 835
 836         DBG("Event agent disabling for trigger %" PRIu64, lttng_trigger_get_tracer_token(trigger));
 837
 838         const lttng::urcu::read_lock_guard read_lock;
 839         aevent = agent_find_event_by_trigger(trigger, agt);
 840
 841         if (aevent == nullptr) {
 842                 DBG2("Event agent NOT found by trigger %" PRIu64,
 843                      lttng_trigger_get_tracer_token(trigger));
 844                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 845                 goto end;
 846         }
 847
 848         ret = trigger_agent_disable_one(trigger, agt, aevent);
 849
 850         if (ret != LTTNG_OK) {
 851                 goto end;
 852         }
 853
 854 end:
 855         return ret;
 856 }
 857
 858 /*
 859  * Disable all agent events matching a given name for a given UST session.
 860  *
 861  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 862  */
 863 int event_agent_disable(struct ltt_ust_session *usess, struct agent *agt, const char *event_name)
 864 {
 865         int ret = LTTNG_OK;
 866         struct agent_event *aevent;
 867         struct lttng_ht_iter iter;
 868         struct lttng_ht_node_str *node;
 869
 870         LTTNG_ASSERT(agt);
 871         LTTNG_ASSERT(usess);
 872         LTTNG_ASSERT(event_name);
 873
 874         DBG("Event agent disabling %s (all loglevels) for session %" PRIu64, event_name, usess->id);
 875
 876         const lttng::urcu::read_lock_guard read_lock;
 877         agent_find_events_by_name(event_name, agt, &iter);
 878         node = lttng_ht_iter_get_node<lttng_ht_node_str>(&iter);
 879
 880         if (node == nullptr) {
 881                 DBG2("Event agent NOT found by name %s", event_name);
 882                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 883                 goto end;
 884         }
 885
 886         do {
 887                 aevent = lttng::utils::container_of(node, &agent_event::node);
 888                 ret = event_agent_disable_one(usess, agt, aevent);
 889
 890                 if (ret != LTTNG_OK) {
 891                         goto end;
 892                 }
 893
 894                 /* Get next duplicate agent event by name. */
 895                 agent_event_next_duplicate(event_name, agt, &iter);
 896                 node = lttng_ht_iter_get_node<lttng_ht_node_str>(&iter);
 897         } while (node);
 898 end:
 899         return ret;
 900 }
 901 /*
 902  * Disable all agent event for a given UST session.
 903  *
 904  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 905  */
 906 int event_agent_disable_all(struct ltt_ust_session *usess, struct agent *agt)
 907 {
 908         int ret;
 909
 910         LTTNG_ASSERT(agt);
 911         LTTNG_ASSERT(usess);
 912
 913         /*
 914          * Disable event on agent application. Continue to disable all other events
 915          * if the * event is not found.
 916          */
 917         ret = event_agent_disable(usess, agt, "*");
 918         if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_NOT_FOUND) {
 919                 goto error;
 920         }
 921
 922         /* Disable every event. */
 923         for (auto *aevent :
 924              lttng::urcu::lfht_iteration_adapter<agent_event,
 925                                                  decltype(agent_event::node),
 926                                                  &agent_event::node>(*agt->events->ht)) {
 927                 if (!AGENT_EVENT_IS_ENABLED(aevent)) {
 928                         continue;
 929                 }
 930
 931                 ret = event_agent_disable(usess, agt, aevent->name);
 932                 if (ret != LTTNG_OK) {
 933                         goto error_unlock;
 934                 }
 935         }
 936
 937         ret = LTTNG_OK;
 938
 939 error_unlock:
 940 error:
 941         return ret;
 942 }