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         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         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_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_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_ht_iter iter;
 323         struct ltt_ust_event *uevent = nullptr;
 324         struct lttng_event *events = nullptr;
 325
 326         LTTNG_ASSERT(usess);
 327         LTTNG_ASSERT(uchan);
 328
 329
 330         /* Disabling existing events */
 331         {
 332                 lttng::urcu::read_lock_guard read_lock;
 333
 334                 cds_lfht_for_each_entry (uchan->events->ht, &iter.iter, uevent, node.node) {
 335                         if (uevent->enabled) {
 336                                 ret = event_ust_disable_tracepoint(usess, uchan, uevent->attr.name);
 337                                 if (ret < 0) {
 338                                         error = LTTNG_ERR_UST_DISABLE_FAIL;
 339                                         continue;
 340                                 }
 341                         }
 342                 }
 343         }
 344
 345         /* Get all UST available events */
 346         size = ust_app_list_events(&events);
 347         if (size < 0) {
 348                 ret = LTTNG_ERR_UST_LIST_FAIL;
 349                 goto error;
 350         }
 351
 352         for (i = 0; i < size; i++) {
 353                 ret = event_ust_disable_tracepoint(usess, uchan, events[i].name);
 354                 if (ret < 0) {
 355                         /* Continue to disable the rest... */
 356                         error = LTTNG_ERR_UST_DISABLE_FAIL;
 357                         continue;
 358                 }
 359         }
 360
 361         ret = error ? error : LTTNG_OK;
 362 error:
 363         free(events);
 364         return ret;
 365 }
 366
 367 static void agent_enable_all(struct agent *agt)
 368 {
 369         struct agent_event *aevent;
 370         struct lttng_ht_iter iter;
 371
 372         {
 373                 /* Flag every event as enabled. */
 374                 lttng::urcu::read_lock_guard read_lock;
 375
 376                 cds_lfht_for_each_entry (agt->events->ht, &iter.iter, aevent, node.node) {
 377                         aevent->enabled_count++;
 378                 }
 379         }
 380 }
 381
 382 /*
 383  * Enable all agent event for a given UST session.
 384  *
 385  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 386  */
 387 int event_agent_enable_all(struct ltt_ust_session *usess,
 388                            struct agent *agt,
 389                            struct lttng_event *event,
 390                            struct lttng_bytecode *filter,
 391                            char *filter_expression)
 392 {
 393         int ret;
 394
 395         LTTNG_ASSERT(usess);
 396
 397         DBG("Event agent enabling ALL events for session %" PRIu64, usess->id);
 398
 399         /* Enable event on agent application through TCP socket. */
 400         ret = event_agent_enable(usess, agt, event, filter, filter_expression);
 401         if (ret != LTTNG_OK) {
 402                 goto error;
 403         }
 404
 405         agent_enable_all(agt);
 406
 407         ret = LTTNG_OK;
 408
 409 error:
 410         return ret;
 411 }
 412
 413 /*
 414  * Check if this event's filter requires the activation of application contexts
 415  * and enable them in the agent.
 416  * TODO: bytecode iterator does not support non-legacy application
 417  * contexts yet. Not an issue for now, since they are not generated by
 418  * the lttng-ctl library.
 419  */
 420 static int add_filter_app_ctx(struct lttng_bytecode *bytecode,
 421                               const char *filter_expression,
 422                               struct agent *agt)
 423 {
 424         int ret = LTTNG_OK;
 425         char *provider_name = nullptr, *ctx_name = nullptr;
 426         struct bytecode_symbol_iterator *it = bytecode_symbol_iterator_create(bytecode);
 427
 428         if (!it) {
 429                 ret = LTTNG_ERR_NOMEM;
 430                 goto end;
 431         }
 432
 433         do {
 434                 struct lttng_event_context ctx;
 435                 const char *symbol_name = bytecode_symbol_iterator_get_name(it);
 436
 437                 if (parse_application_context(symbol_name, &provider_name, &ctx_name)) {
 438                         /* Not an application context. */
 439                         continue;
 440                 }
 441
 442                 ctx.ctx = LTTNG_EVENT_CONTEXT_APP_CONTEXT;
 443                 ctx.u.app_ctx.provider_name = provider_name;
 444                 ctx.u.app_ctx.ctx_name = ctx_name;
 445
 446                 /* Recognized an application context. */
 447                 DBG("Enabling event with filter expression \"%s\" requires enabling the %s:%s application context.",
 448                     filter_expression,
 449                     provider_name,
 450                     ctx_name);
 451
 452                 ret = agent_add_context(&ctx, agt);
 453                 if (ret != LTTNG_OK) {
 454                         ERR("Failed to add application context %s:%s.", provider_name, ctx_name);
 455                         goto end;
 456                 }
 457
 458                 ret = agent_enable_context(&ctx, agt->domain);
 459                 if (ret != LTTNG_OK) {
 460                         ERR("Failed to enable application context %s:%s.", provider_name, ctx_name);
 461                         goto end;
 462                 }
 463
 464                 free(provider_name);
 465                 free(ctx_name);
 466                 provider_name = ctx_name = nullptr;
 467         } while (bytecode_symbol_iterator_next(it) == 0);
 468 end:
 469         free(provider_name);
 470         free(ctx_name);
 471         bytecode_symbol_iterator_destroy(it);
 472         return ret;
 473 }
 474
 475 static int agent_enable(struct agent *agt,
 476                         struct lttng_event *event,
 477                         struct lttng_bytecode *filter,
 478                         char *filter_expression)
 479 {
 480         int ret, created = 0;
 481         struct agent_event *aevent;
 482
 483         LTTNG_ASSERT(event);
 484         LTTNG_ASSERT(agt);
 485
 486         lttng::urcu::read_lock_guard read_lock;
 487         aevent = agent_find_event(
 488                 event->name, event->loglevel_type, event->loglevel, filter_expression, agt);
 489         if (!aevent) {
 490                 aevent = agent_create_event(event->name,
 491                                             event->loglevel_type,
 492                                             event->loglevel,
 493                                             filter,
 494                                             filter_expression);
 495                 if (!aevent) {
 496                         ret = LTTNG_ERR_NOMEM;
 497                         goto error;
 498                 }
 499                 filter = nullptr;
 500                 filter_expression = nullptr;
 501                 created = 1;
 502                 LTTNG_ASSERT(!AGENT_EVENT_IS_ENABLED(aevent));
 503         }
 504
 505         if (created && aevent->filter) {
 506                 ret = add_filter_app_ctx(aevent->filter, aevent->filter_expression, agt);
 507                 if (ret != LTTNG_OK) {
 508                         goto error;
 509                 }
 510         }
 511
 512         /* Already enabled? */
 513         if (AGENT_EVENT_IS_ENABLED(aevent)) {
 514                 ret = LTTNG_OK;
 515                 goto end;
 516         }
 517
 518         ret = agent_enable_event(aevent, agt->domain);
 519         if (ret != LTTNG_OK) {
 520                 goto error;
 521         }
 522
 523         /* If the event was created prior to the enable, add it to the domain. */
 524         if (created) {
 525                 agent_add_event(aevent, agt);
 526         }
 527
 528         ret = LTTNG_OK;
 529         goto end;
 530
 531 error:
 532         if (created) {
 533                 agent_destroy_event(aevent);
 534         }
 535 end:
 536         free(filter);
 537         free(filter_expression);
 538         return ret;
 539 }
 540
 541 /*
 542  * Enable a single agent event for a given UST session.
 543  *
 544  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 545  */
 546 int event_agent_enable(struct ltt_ust_session *usess,
 547                        struct agent *agt,
 548                        struct lttng_event *event,
 549                        struct lttng_bytecode *filter,
 550                        char *filter_expression)
 551 {
 552         LTTNG_ASSERT(usess);
 553         LTTNG_ASSERT(event);
 554         LTTNG_ASSERT(agt);
 555
 556         DBG("Enabling agent event: event pattern = '%s', session id = %" PRIu64
 557             ", loglevel type = %d, loglevel = %d, filter expression = '%s'",
 558             event->name,
 559             usess->id,
 560             event->loglevel_type,
 561             event->loglevel,
 562             filter_expression ? filter_expression : "(none)");
 563
 564         return agent_enable(agt, event, filter, filter_expression);
 565 }
 566
 567 /*
 568  * Enable a single agent event for a trigger.
 569  *
 570  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 571  */
 572 int trigger_agent_enable(const struct lttng_trigger *trigger, struct agent *agt)
 573 {
 574         int ret;
 575         enum lttng_condition_status c_status;
 576         enum lttng_trigger_status t_status;
 577         enum lttng_domain_type d_type;
 578         const struct lttng_condition *condition;
 579         const struct lttng_event_rule *rule;
 580         const char *filter_expression;
 581         char *filter_expression_copy = nullptr;
 582         const struct lttng_bytecode *filter_bytecode;
 583         struct lttng_bytecode *filter_bytecode_copy = nullptr;
 584         struct lttng_event *event = nullptr;
 585         uid_t trigger_owner_uid = 0;
 586         const char *trigger_name;
 587
 588         LTTNG_ASSERT(trigger);
 589         LTTNG_ASSERT(agt);
 590
 591         t_status = lttng_trigger_get_name(trigger, &trigger_name);
 592         if (t_status != LTTNG_TRIGGER_STATUS_OK) {
 593                 trigger_name = "(anonymous)";
 594         }
 595
 596         t_status = lttng_trigger_get_owner_uid(trigger, &trigger_owner_uid);
 597         LTTNG_ASSERT(t_status == LTTNG_TRIGGER_STATUS_OK);
 598
 599         condition = lttng_trigger_get_const_condition(trigger);
 600
 601         LTTNG_ASSERT(lttng_condition_get_type(condition) ==
 602                      LTTNG_CONDITION_TYPE_EVENT_RULE_MATCHES);
 603
 604         c_status = lttng_condition_event_rule_matches_get_rule(condition, &rule);
 605         LTTNG_ASSERT(c_status == LTTNG_CONDITION_STATUS_OK);
 606
 607         switch (lttng_event_rule_get_type(rule)) {
 608         case LTTNG_EVENT_RULE_TYPE_JUL_LOGGING:
 609         case LTTNG_EVENT_RULE_TYPE_LOG4J_LOGGING:
 610         case LTTNG_EVENT_RULE_TYPE_PYTHON_LOGGING:
 611                 break;
 612         default:
 613                 abort();
 614                 break;
 615         }
 616
 617         d_type = lttng_event_rule_get_domain_type(rule);
 618         LTTNG_ASSERT(d_type == agt->domain);
 619
 620         event = lttng_event_rule_generate_lttng_event(rule);
 621         if (!event) {
 622                 ret = LTTNG_ERR_NOMEM;
 623                 goto end;
 624         }
 625
 626         /* Get the internal filter expression and bytecode. */
 627         filter_expression = lttng_event_rule_get_filter(rule);
 628         if (filter_expression) {
 629                 filter_expression_copy = strdup(filter_expression);
 630                 if (!filter_expression_copy) {
 631                         ret = LTTNG_ERR_NOMEM;
 632                         goto end;
 633                 }
 634
 635                 /* Get the filter bytecode */
 636                 filter_bytecode = lttng_event_rule_get_filter_bytecode(rule);
 637                 if (filter_bytecode) {
 638                         filter_bytecode_copy = lttng_bytecode_copy(filter_bytecode);
 639                         if (!filter_bytecode_copy) {
 640                                 ret = LTTNG_ERR_NOMEM;
 641                                 goto end;
 642                         }
 643                 }
 644         }
 645
 646         DBG("Enabling agent event from trigger: trigger name = '%s', trigger owner uid = %d, token = %" PRIu64,
 647             trigger_name,
 648             trigger_owner_uid,
 649             lttng_trigger_get_tracer_token(trigger));
 650
 651         ret = agent_enable(agt, event, filter_bytecode_copy, filter_expression_copy);
 652         /* Ownership was passed even in case of error. */
 653         filter_expression_copy = nullptr;
 654         filter_bytecode_copy = nullptr;
 655
 656 end:
 657         free(filter_expression_copy);
 658         free(filter_bytecode_copy);
 659         free(event);
 660         return ret;
 661 }
 662
 663 /*
 664  * Return the default event name associated with the provided UST domain. Return
 665  * NULL on error.
 666  */
 667 const char *event_get_default_agent_ust_name(enum lttng_domain_type domain)
 668 {
 669         const char *default_event_name = nullptr;
 670
 671         switch (domain) {
 672         case LTTNG_DOMAIN_LOG4J:
 673                 default_event_name = DEFAULT_LOG4J_EVENT_NAME;
 674                 break;
 675         case LTTNG_DOMAIN_JUL:
 676                 default_event_name = DEFAULT_JUL_EVENT_NAME;
 677                 break;
 678         case LTTNG_DOMAIN_PYTHON:
 679                 default_event_name = DEFAULT_PYTHON_EVENT_NAME;
 680                 break;
 681         default:
 682                 abort();
 683         }
 684
 685         return default_event_name;
 686 }
 687
 688 static int trigger_agent_disable_one(const struct lttng_trigger *trigger,
 689                                      struct agent *agt,
 690                                      struct agent_event *aevent)
 691
 692 {
 693         int ret;
 694
 695         LTTNG_ASSERT(agt);
 696         LTTNG_ASSERT(trigger);
 697         LTTNG_ASSERT(aevent);
 698
 699         /*
 700          * Actual ust event un-registration happens on the trigger
 701          * un-registration at that point.
 702          */
 703
 704         DBG("Event agent disabling %s (loglevel type %d, loglevel value %d) for trigger %" PRIu64,
 705             aevent->name,
 706             aevent->loglevel_type,
 707             aevent->loglevel_value,
 708             lttng_trigger_get_tracer_token(trigger));
 709
 710         /* Already disabled? */
 711         if (!AGENT_EVENT_IS_ENABLED(aevent)) {
 712                 goto end;
 713         }
 714
 715         ret = agent_disable_event(aevent, agt->domain);
 716         if (ret != LTTNG_OK) {
 717                 goto error;
 718         }
 719
 720 end:
 721         return LTTNG_OK;
 722
 723 error:
 724         return ret;
 725 }
 726
 727 /*
 728  * Disable a given agent event for a given UST session.
 729  *
 730  * Must be called with the RCU read lock held.
 731  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 732  */
 733 static int event_agent_disable_one(struct ltt_ust_session *usess,
 734                                    struct agent *agt,
 735                                    struct agent_event *aevent)
 736 {
 737         int ret;
 738         struct ltt_ust_event *uevent = nullptr;
 739         struct ltt_ust_channel *uchan = nullptr;
 740         const char *ust_event_name, *ust_channel_name;
 741
 742         LTTNG_ASSERT(agt);
 743         LTTNG_ASSERT(usess);
 744         LTTNG_ASSERT(aevent);
 745
 746         DBG("Event agent disabling %s (loglevel type %d, loglevel value %d) for session %" PRIu64,
 747             aevent->name,
 748             aevent->loglevel_type,
 749             aevent->loglevel_value,
 750             usess->id);
 751
 752         /* Already disabled? */
 753         if (!AGENT_EVENT_IS_ENABLED(aevent)) {
 754                 goto end;
 755         }
 756
 757         if (agt->domain == LTTNG_DOMAIN_JUL) {
 758                 ust_channel_name = DEFAULT_JUL_CHANNEL_NAME;
 759         } else if (agt->domain == LTTNG_DOMAIN_LOG4J) {
 760                 ust_channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
 761         } else if (agt->domain == LTTNG_DOMAIN_PYTHON) {
 762                 ust_channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
 763         } else {
 764                 ret = LTTNG_ERR_INVALID;
 765                 goto error;
 766         }
 767
 768         /*
 769          * Disable it on the UST side. First get the channel reference then find
 770          * the event and finally disable it.
 771          */
 772         uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 773                                                (char *) ust_channel_name);
 774         if (!uchan) {
 775                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 776                 goto error;
 777         }
 778
 779         ust_event_name = event_get_default_agent_ust_name(agt->domain);
 780         if (!ust_event_name) {
 781                 ret = LTTNG_ERR_FATAL;
 782                 goto error;
 783         }
 784
 785         /*
 786          * Agent UST event has its loglevel type forced to
 787          * LTTNG_UST_LOGLEVEL_ALL. The actual loglevel type/value filtering
 788          * happens thanks to an UST filter. The following -1 is actually
 789          * ignored since the type is LTTNG_UST_LOGLEVEL_ALL.
 790          */
 791         uevent = trace_ust_find_event(uchan->events,
 792                                       (char *) ust_event_name,
 793                                       aevent->filter,
 794                                       LTTNG_UST_ABI_LOGLEVEL_ALL,
 795                                       -1,
 796                                       nullptr);
 797         /* If the agent event exists, it must be available on the UST side. */
 798         LTTNG_ASSERT(uevent);
 799
 800         if (usess->active) {
 801                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 802                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 803                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 804                         goto error;
 805                 }
 806         }
 807
 808         /*
 809          * Flag event that it's disabled so the shadow copy on the ust app side
 810          * will disable it if an application shows up.
 811          */
 812         uevent->enabled = false;
 813
 814         ret = agent_disable_event(aevent, agt->domain);
 815         if (ret != LTTNG_OK) {
 816                 goto error;
 817         }
 818
 819 end:
 820         return LTTNG_OK;
 821
 822 error:
 823         return ret;
 824 }
 825
 826 /*
 827  * Disable agent event matching a given trigger.
 828  *
 829  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 830  */
 831 int trigger_agent_disable(const struct lttng_trigger *trigger, struct agent *agt)
 832 {
 833         int ret = LTTNG_OK;
 834         struct agent_event *aevent;
 835
 836         LTTNG_ASSERT(trigger);
 837         LTTNG_ASSERT(agt);
 838
 839         DBG("Event agent disabling for trigger %" PRIu64, lttng_trigger_get_tracer_token(trigger));
 840
 841         lttng::urcu::read_lock_guard read_lock;
 842         aevent = agent_find_event_by_trigger(trigger, agt);
 843
 844         if (aevent == nullptr) {
 845                 DBG2("Event agent NOT found by trigger %" PRIu64,
 846                      lttng_trigger_get_tracer_token(trigger));
 847                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 848                 goto end;
 849         }
 850
 851         ret = trigger_agent_disable_one(trigger, agt, aevent);
 852
 853         if (ret != LTTNG_OK) {
 854                 goto end;
 855         }
 856
 857 end:
 858         return ret;
 859 }
 860
 861 /*
 862  * Disable all agent events matching a given name for a given UST session.
 863  *
 864  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 865  */
 866 int event_agent_disable(struct ltt_ust_session *usess, struct agent *agt, const char *event_name)
 867 {
 868         int ret = LTTNG_OK;
 869         struct agent_event *aevent;
 870         struct lttng_ht_iter iter;
 871         struct lttng_ht_node_str *node;
 872
 873         LTTNG_ASSERT(agt);
 874         LTTNG_ASSERT(usess);
 875         LTTNG_ASSERT(event_name);
 876
 877         DBG("Event agent disabling %s (all loglevels) for session %" PRIu64, event_name, usess->id);
 878
 879         lttng::urcu::read_lock_guard read_lock;
 880         agent_find_events_by_name(event_name, agt, &iter);
 881         node = lttng_ht_iter_get_node_str(&iter);
 882
 883         if (node == nullptr) {
 884                 DBG2("Event agent NOT found by name %s", event_name);
 885                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 886                 goto end;
 887         }
 888
 889         do {
 890                 aevent = lttng::utils::container_of(node, &agent_event::node);
 891                 ret = event_agent_disable_one(usess, agt, aevent);
 892
 893                 if (ret != LTTNG_OK) {
 894                         goto end;
 895                 }
 896
 897                 /* Get next duplicate agent event by name. */
 898                 agent_event_next_duplicate(event_name, agt, &iter);
 899                 node = lttng_ht_iter_get_node_str(&iter);
 900         } while (node);
 901 end:
 902         return ret;
 903 }
 904 /*
 905  * Disable all agent event for a given UST session.
 906  *
 907  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 908  */
 909 int event_agent_disable_all(struct ltt_ust_session *usess, struct agent *agt)
 910 {
 911         int ret;
 912         struct agent_event *aevent;
 913         struct lttng_ht_iter iter;
 914
 915         LTTNG_ASSERT(agt);
 916         LTTNG_ASSERT(usess);
 917
 918         /*
 919          * Disable event on agent application. Continue to disable all other events
 920          * if the * event is not found.
 921          */
 922         ret = event_agent_disable(usess, agt, "*");
 923         if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_NOT_FOUND) {
 924                 goto error;
 925         }
 926
 927         /* Disable every event. */
 928         {
 929                 lttng::urcu::read_lock_guard read_lock;
 930
 931                 cds_lfht_for_each_entry (agt->events->ht, &iter.iter, aevent, node.node) {
 932                         if (!AGENT_EVENT_IS_ENABLED(aevent)) {
 933                                 continue;
 934                         }
 935
 936                         ret = event_agent_disable(usess, agt, aevent->name);
 937                         if (ret != LTTNG_OK) {
 938                                 goto error_unlock;
 939                         }
 940                 }
 941         }
 942
 943         ret = LTTNG_OK;
 944
 945 error_unlock:
 946 error:
 947         return ret;
 948 }