src/bin/lttng-sessiond/event.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _LGPL_SOURCE
  20 #include <errno.h>
  21 #include <urcu/list.h>
  22 #include <string.h>
  23
  24 #include <lttng/lttng.h>
  25 #include <common/error.h>
  26 #include <common/sessiond-comm/sessiond-comm.h>
  27 #include <common/filter.h>
  28 #include <common/context.h>
  29
  30 #include "channel.h"
  31 #include "event.h"
  32 #include "kernel.h"
  33 #include "lttng-sessiond.h"
  34 #include "lttng-ust-ctl.h"
  35 #include "lttng-ust-error.h"
  36 #include "ust-app.h"
  37 #include "trace-kernel.h"
  38 #include "trace-ust.h"
  39 #include "agent.h"
  40
  41 /*
  42  * Add unique UST event based on the event name, filter bytecode and loglevel.
  43  */
  44 static void add_unique_ust_event(struct lttng_ht *ht,
  45                 struct ltt_ust_event *event)
  46 {
  47         struct cds_lfht_node *node_ptr;
  48         struct ltt_ust_ht_key key;
  49
  50         assert(ht);
  51         assert(ht->ht);
  52         assert(event);
  53
  54         key.name = event->attr.name;
  55         key.filter = (struct lttng_filter_bytecode *) event->filter;
  56         key.loglevel_type = event->attr.loglevel_type;
  57         key.loglevel_value = event->attr.loglevel;
  58         key.exclusion = event->exclusion;
  59
  60         node_ptr = cds_lfht_add_unique(ht->ht,
  61                         ht->hash_fct(event->node.key, lttng_ht_seed),
  62                         trace_ust_ht_match_event, &key, &event->node.node);
  63         assert(node_ptr == &event->node.node);
  64 }
  65
  66 /*
  67  * Disable kernel tracepoint events for a channel from the kernel session of
  68  * a specified event_name and event type.
  69  * On type LTTNG_EVENT_ALL all events with event_name are disabled.
  70  * If event_name is NULL all events of the specified type are disabled.
  71  */
  72 int event_kernel_disable_event(struct ltt_kernel_channel *kchan,
  73                 const char *event_name, enum lttng_event_type type)
  74 {
  75         int ret, error = 0, found = 0;
  76         struct ltt_kernel_event *kevent;
  77
  78         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 != NULL && strcmp(event_name, kevent->event->name)) {
  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, event_name ? event_name : "NULL", type);
  96
  97         if (event_name != NULL && !found) {
  98                 ret = LTTNG_ERR_NO_EVENT;
  99         } else {
 100                 ret = error ? LTTNG_ERR_KERN_DISABLE_FAIL : LTTNG_OK;
 101         }
 102
 103         return ret;
 104 }
 105
 106 /*
 107  * Enable kernel tracepoint event for a channel from the kernel session.
 108  * We own filter_expression and filter.
 109  */
 110 int event_kernel_enable_event(struct ltt_kernel_channel *kchan,
 111                 struct lttng_event *event, char *filter_expression,
 112                 struct lttng_filter_bytecode *filter)
 113 {
 114         int ret;
 115         struct ltt_kernel_event *kevent;
 116
 117         assert(kchan);
 118         assert(event);
 119
 120         kevent = trace_kernel_find_event(event->name, kchan,
 121                         event->type, filter);
 122         if (kevent == NULL) {
 123                 ret = kernel_create_event(event, kchan, filter_expression, filter);
 124                 /* We have passed ownership */
 125                 filter_expression = NULL;
 126                 filter = NULL;
 127                 if (ret) {
 128                         goto end;
 129                 }
 130         } else if (kevent->enabled == 0) {
 131                 ret = kernel_enable_event(kevent);
 132                 if (ret < 0) {
 133                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 134                         goto end;
 135                 }
 136         } else {
 137                 /* At this point, the event is considered enabled */
 138                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 139                 goto end;
 140         }
 141
 142         ret = LTTNG_OK;
 143 end:
 144         free(filter_expression);
 145         free(filter);
 146         return ret;
 147 }
 148
 149 /*
 150  * ============================
 151  * UST : The Ultimate Frontier!
 152  * ============================
 153  */
 154
 155 /*
 156  * Enable UST tracepoint event for a channel from a UST session.
 157  * We own filter_expression, filter, and exclusion.
 158  */
 159 int event_ust_enable_tracepoint(struct ltt_ust_session *usess,
 160                 struct ltt_ust_channel *uchan, struct lttng_event *event,
 161                 char *filter_expression,
 162                 struct lttng_filter_bytecode *filter,
 163                 struct lttng_event_exclusion *exclusion,
 164                 bool internal_event)
 165 {
 166         int ret = LTTNG_OK, to_create = 0;
 167         struct ltt_ust_event *uevent;
 168
 169         assert(usess);
 170         assert(uchan);
 171         assert(event);
 172
 173         rcu_read_lock();
 174
 175         uevent = trace_ust_find_event(uchan->events, event->name, filter,
 176                         (enum lttng_ust_loglevel_type) event->loglevel_type,
 177                         event->loglevel, exclusion);
 178         if (!uevent) {
 179                 ret = trace_ust_create_event(event, filter_expression,
 180                                 filter, exclusion, internal_event, &uevent);
 181                 /* We have passed ownership */
 182                 filter_expression = NULL;
 183                 filter = NULL;
 184                 exclusion = NULL;
 185                 if (ret != LTTNG_OK) {
 186                         goto end;
 187                 }
 188
 189                 /* Valid to set it after the goto error since uevent is still NULL */
 190                 to_create = 1;
 191         }
 192
 193         if (uevent->enabled) {
 194                 /* It's already enabled so everything is OK */
 195                 assert(!to_create);
 196                 ret = LTTNG_ERR_UST_EVENT_ENABLED;
 197                 goto end;
 198         }
 199
 200         uevent->enabled = 1;
 201         if (to_create) {
 202                 /* Add ltt ust event to channel */
 203                 add_unique_ust_event(uchan->events, uevent);
 204         }
 205
 206         if (!usess->active) {
 207                 goto end;
 208         }
 209
 210         if (to_create) {
 211                 /* Create event on all UST registered apps for session */
 212                 ret = ust_app_create_event_glb(usess, uchan, uevent);
 213         } else {
 214                 /* Enable event on all UST registered apps for session */
 215                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 216         }
 217
 218         if (ret < 0) {
 219                 if (ret == -LTTNG_UST_ERR_EXIST) {
 220                         ret = LTTNG_ERR_UST_EVENT_EXIST;
 221                 } else {
 222                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 223                 }
 224                 goto end;
 225         }
 226
 227         DBG("Event UST %s %s in channel %s", uevent->attr.name,
 228                         to_create ? "created" : "enabled", uchan->name);
 229
 230         ret = LTTNG_OK;
 231
 232 end:
 233         rcu_read_unlock();
 234         free(filter_expression);
 235         free(filter);
 236         free(exclusion);
 237         return ret;
 238 }
 239
 240 /*
 241  * Disable UST tracepoint of a channel from a UST session.
 242  */
 243 int event_ust_disable_tracepoint(struct ltt_ust_session *usess,
 244                 struct ltt_ust_channel *uchan, const char *event_name)
 245 {
 246         int ret;
 247         struct ltt_ust_event *uevent;
 248         struct lttng_ht_node_str *node;
 249         struct lttng_ht_iter iter;
 250         struct lttng_ht *ht;
 251
 252         assert(usess);
 253         assert(uchan);
 254         assert(event_name);
 255
 256         ht = uchan->events;
 257
 258         rcu_read_lock();
 259
 260         /*
 261          * We use a custom lookup since we need the iterator for the next_duplicate
 262          * call in the do while loop below.
 263          */
 264         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) event_name, lttng_ht_seed),
 265                         trace_ust_ht_match_event_by_name, event_name, &iter.iter);
 266         node = lttng_ht_iter_get_node_str(&iter);
 267         if (node == NULL) {
 268                 DBG2("Trace UST event NOT found by name %s", event_name);
 269                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 270                 goto error;
 271         }
 272
 273         do {
 274                 uevent = caa_container_of(node, struct ltt_ust_event, node);
 275                 assert(uevent);
 276
 277                 if (uevent->enabled == 0) {
 278                         /* It's already disabled so everything is OK */
 279                         goto next;
 280                 }
 281                 uevent->enabled = 0;
 282                 DBG2("Event UST %s disabled in channel %s", uevent->attr.name,
 283                                 uchan->name);
 284
 285                 if (!usess->active) {
 286                         goto next;
 287                 }
 288                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 289                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 290                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 291                         goto error;
 292                 }
 293 next:
 294                 /* Get next duplicate event by name. */
 295                 cds_lfht_next_duplicate(ht->ht, trace_ust_ht_match_event_by_name,
 296                                 event_name, &iter.iter);
 297                 node = lttng_ht_iter_get_node_str(&iter);
 298         } while (node);
 299
 300         ret = LTTNG_OK;
 301
 302 error:
 303         rcu_read_unlock();
 304         return ret;
 305 }
 306
 307 /*
 308  * Disable all UST tracepoints for a channel from a UST session.
 309  */
 310 int event_ust_disable_all_tracepoints(struct ltt_ust_session *usess,
 311                 struct ltt_ust_channel *uchan)
 312 {
 313         int ret, i, size, error = 0;
 314         struct lttng_ht_iter iter;
 315         struct ltt_ust_event *uevent = NULL;
 316         struct lttng_event *events = NULL;
 317
 318         assert(usess);
 319         assert(uchan);
 320
 321         rcu_read_lock();
 322
 323         /* Disabling existing events */
 324         cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 325                         node.node) {
 326                 if (uevent->enabled == 1) {
 327                         ret = event_ust_disable_tracepoint(usess, uchan,
 328                                         uevent->attr.name);
 329                         if (ret < 0) {
 330                                 error = LTTNG_ERR_UST_DISABLE_FAIL;
 331                                 continue;
 332                         }
 333                 }
 334         }
 335
 336         /* Get all UST available events */
 337         size = ust_app_list_events(&events);
 338         if (size < 0) {
 339                 ret = LTTNG_ERR_UST_LIST_FAIL;
 340                 goto error;
 341         }
 342
 343         for (i = 0; i < size; i++) {
 344                 ret = event_ust_disable_tracepoint(usess, uchan,
 345                                 events[i].name);
 346                 if (ret < 0) {
 347                         /* Continue to disable the rest... */
 348                         error = LTTNG_ERR_UST_DISABLE_FAIL;
 349                         continue;
 350                 }
 351         }
 352
 353         ret = error ? error : LTTNG_OK;
 354 error:
 355         rcu_read_unlock();
 356         free(events);
 357         return ret;
 358 }
 359
 360 /*
 361  * Enable all agent event for a given UST session.
 362  *
 363  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 364  */
 365 int event_agent_enable_all(struct ltt_ust_session *usess,
 366                 struct agent *agt, struct lttng_event *event,
 367                 struct lttng_filter_bytecode *filter ,char *filter_expression)
 368 {
 369         int ret;
 370         struct agent_event *aevent;
 371         struct lttng_ht_iter iter;
 372
 373         assert(usess);
 374
 375         DBG("Event agent enabling ALL events for session %" PRIu64, usess->id);
 376
 377         /* Enable event on agent application through TCP socket. */
 378         ret = event_agent_enable(usess, agt, event, filter, filter_expression);
 379         if (ret != LTTNG_OK) {
 380                 goto error;
 381         }
 382
 383         /* Flag every event that they are now enabled. */
 384         rcu_read_lock();
 385         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 386                         node.node) {
 387                 aevent->enabled = 1;
 388         }
 389         rcu_read_unlock();
 390
 391         ret = LTTNG_OK;
 392
 393 error:
 394         return ret;
 395 }
 396
 397 /*
 398  * Check if this event's filter requires the activation of application contexts
 399  * and enable them in the agent.
 400  * TODO: bytecode iterator does not support non-legacy application
 401  * contexts yet. Not an issue for now, since they are not generated by
 402  * the lttng-ctl library.
 403  */
 404 static int add_filter_app_ctx(struct lttng_filter_bytecode *bytecode,
 405                 const char *filter_expression, struct agent *agt)
 406 {
 407         int ret = LTTNG_OK;
 408         char *provider_name = NULL, *ctx_name = NULL;
 409         struct bytecode_symbol_iterator *it =
 410                         bytecode_symbol_iterator_create(bytecode);
 411
 412         if (!it) {
 413                 ret = LTTNG_ERR_NOMEM;
 414                 goto end;
 415         }
 416
 417         do {
 418                 struct lttng_event_context ctx;
 419                 const char *symbol_name =
 420                                 bytecode_symbol_iterator_get_name(it);
 421
 422                 if (parse_application_context(symbol_name, &provider_name,
 423                                 &ctx_name)) {
 424                         /* Not an application context. */
 425                         continue;
 426                 }
 427
 428                 ctx.ctx = LTTNG_EVENT_CONTEXT_APP_CONTEXT;
 429                 ctx.u.app_ctx.provider_name = provider_name;
 430                 ctx.u.app_ctx.ctx_name = ctx_name;
 431
 432                 /* Recognized an application context. */
 433                 DBG("Enabling event with filter expression \"%s\" requires enabling the %s:%s application context.",
 434                                 filter_expression, provider_name, ctx_name);
 435
 436                 ret = agent_add_context(&ctx, agt);
 437                 if (ret != LTTNG_OK) {
 438                         ERR("Failed to add application context %s:%s.",
 439                                         provider_name, ctx_name);
 440                         goto end;
 441                 }
 442
 443                 ret = agent_enable_context(&ctx, agt->domain);
 444                 if (ret != LTTNG_OK) {
 445                         ERR("Failed to enable application context %s:%s.",
 446                                         provider_name, ctx_name);
 447                         goto end;
 448                 }
 449
 450                 free(provider_name);
 451                 free(ctx_name);
 452                 provider_name = ctx_name = NULL;
 453         } while (bytecode_symbol_iterator_next(it) == 0);
 454 end:
 455         free(provider_name);
 456         free(ctx_name);
 457         bytecode_symbol_iterator_destroy(it);
 458         return ret;
 459 }
 460
 461 /*
 462  * Enable a single agent event for a given UST session.
 463  *
 464  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 465  */
 466 int event_agent_enable(struct ltt_ust_session *usess,
 467                 struct agent *agt, struct lttng_event *event,
 468                 struct lttng_filter_bytecode *filter,
 469                 char *filter_expression)
 470 {
 471         int ret, created = 0;
 472         struct agent_event *aevent;
 473
 474         assert(usess);
 475         assert(event);
 476         assert(agt);
 477
 478         DBG("Event agent enabling %s for session %" PRIu64 " with loglevel type %d "
 479                         ", loglevel %d and filter \"%s\"", event->name,
 480                         usess->id, event->loglevel_type, event->loglevel,
 481                         filter_expression ? filter_expression : "NULL");
 482
 483         aevent = agent_find_event(event->name, event->loglevel_type,
 484                         event->loglevel, filter_expression, agt);
 485         if (!aevent) {
 486                 aevent = agent_create_event(event->name, event->loglevel_type,
 487                                 event->loglevel, filter,
 488                                 filter_expression);
 489                 if (!aevent) {
 490                         ret = LTTNG_ERR_NOMEM;
 491                         goto error;
 492                 }
 493                 filter = NULL;
 494                 filter_expression = NULL;
 495                 created = 1;
 496                 assert(!aevent->enabled);
 497         }
 498
 499         if (created && aevent->filter) {
 500                 ret = add_filter_app_ctx(
 501                                 aevent->filter, aevent->filter_expression, agt);
 502                 if (ret != LTTNG_OK) {
 503                         goto error;
 504                 }
 505         }
 506
 507         /* Already enabled? */
 508         if (aevent->enabled) {
 509                 ret = LTTNG_OK;
 510                 goto end;
 511         }
 512
 513         ret = agent_enable_event(aevent, agt->domain);
 514         if (ret != LTTNG_OK) {
 515                 goto error;
 516         }
 517
 518         /* If the event was created prior to the enable, add it to the domain. */
 519         if (created) {
 520                 agent_add_event(aevent, agt);
 521         }
 522
 523         ret = LTTNG_OK;
 524         goto end;
 525
 526 error:
 527         if (created) {
 528                 agent_destroy_event(aevent);
 529         }
 530 end:
 531         free(filter);
 532         free(filter_expression);
 533         return ret;
 534 }
 535
 536 /*
 537  * Return the default event name associated with the provided UST domain. Return
 538  * NULL on error.
 539  */
 540 const char *event_get_default_agent_ust_name(enum lttng_domain_type domain)
 541 {
 542         const char *default_event_name = NULL;
 543
 544         switch (domain) {
 545         case LTTNG_DOMAIN_LOG4J:
 546                 default_event_name = DEFAULT_LOG4J_EVENT_NAME;
 547                 break;
 548         case LTTNG_DOMAIN_JUL:
 549                 default_event_name = DEFAULT_JUL_EVENT_NAME;
 550                 break;
 551         case LTTNG_DOMAIN_PYTHON:
 552                 default_event_name = DEFAULT_PYTHON_EVENT_NAME;
 553                 break;
 554         default:
 555                 assert(0);
 556         }
 557
 558         return default_event_name;
 559 }
 560
 561 /*
 562  * Disable a given agent event for a given UST session.
 563  *
 564  * Must be called with the RCU read lock held.
 565  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 566  */
 567 static int event_agent_disable_one(struct ltt_ust_session *usess,
 568                 struct agent *agt, struct agent_event *aevent)
 569 {
 570         int ret;
 571         struct ltt_ust_event *uevent = NULL;
 572         struct ltt_ust_channel *uchan = NULL;
 573         const char *ust_event_name, *ust_channel_name;
 574
 575         assert(agt);
 576         assert(usess);
 577         assert(aevent);
 578
 579         DBG("Event agent disabling %s (loglevel type %d, loglevel value %d) for session %" PRIu64,
 580                 aevent->name, aevent->loglevel_type, aevent->loglevel_value,
 581                 usess->id);
 582
 583         /* Already disabled? */
 584         if (!aevent->enabled) {
 585                 goto end;
 586         }
 587
 588         if (agt->domain == LTTNG_DOMAIN_JUL) {
 589                 ust_channel_name = DEFAULT_JUL_CHANNEL_NAME;
 590         } else if (agt->domain == LTTNG_DOMAIN_LOG4J) {
 591                 ust_channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
 592         } else if (agt->domain == LTTNG_DOMAIN_PYTHON) {
 593                 ust_channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
 594         } else {
 595                 ret = LTTNG_ERR_INVALID;
 596                 goto error;
 597         }
 598
 599         /*
 600          * Disable it on the UST side. First get the channel reference then find
 601          * the event and finally disable it.
 602          */
 603         uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 604                         (char *) ust_channel_name);
 605         if (!uchan) {
 606                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 607                 goto error;
 608         }
 609
 610         ust_event_name = event_get_default_agent_ust_name(agt->domain);
 611         if (!ust_event_name) {
 612                 ret = LTTNG_ERR_FATAL;
 613                 goto error;
 614         }
 615
 616         /*
 617          * Agent UST event has its loglevel type forced to
 618          * LTTNG_UST_LOGLEVEL_ALL. The actual loglevel type/value filtering
 619          * happens thanks to an UST filter. The following -1 is actually
 620          * ignored since the type is LTTNG_UST_LOGLEVEL_ALL.
 621          */
 622         uevent = trace_ust_find_event(uchan->events, (char *) ust_event_name,
 623                         aevent->filter, LTTNG_UST_LOGLEVEL_ALL, -1, NULL);
 624         /* If the agent event exists, it must be available on the UST side. */
 625         assert(uevent);
 626
 627         if (usess->active) {
 628                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 629                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 630                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 631                         goto error;
 632                 }
 633         }
 634
 635         /*
 636          * Flag event that it's disabled so the shadow copy on the ust app side
 637          * will disable it if an application shows up.
 638          */
 639         uevent->enabled = 0;
 640
 641         ret = agent_disable_event(aevent, agt->domain);
 642         if (ret != LTTNG_OK) {
 643                 goto error;
 644         }
 645
 646 end:
 647         return LTTNG_OK;
 648
 649 error:
 650         return ret;
 651 }
 652
 653 /*
 654  * Disable all agent events matching a given name for a given UST session.
 655  *
 656  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 657  */
 658 int event_agent_disable(struct ltt_ust_session *usess, struct agent *agt,
 659                 const char *event_name)
 660 {
 661         int ret = LTTNG_OK;
 662         struct agent_event *aevent;
 663         struct lttng_ht_iter iter;
 664         struct lttng_ht_node_str *node;
 665
 666         assert(agt);
 667         assert(usess);
 668         assert(event_name);
 669
 670         DBG("Event agent disabling %s (all loglevels) for session %" PRIu64, event_name, usess->id);
 671
 672         rcu_read_lock();
 673         agent_find_events_by_name(event_name, agt, &iter);
 674         node = lttng_ht_iter_get_node_str(&iter);
 675
 676         if (node == NULL) {
 677                 DBG2("Event agent NOT found by name %s", event_name);
 678                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 679                 goto end;
 680         }
 681
 682         do {
 683                 aevent = caa_container_of(node, struct agent_event, node);
 684                 ret = event_agent_disable_one(usess, agt, aevent);
 685
 686                 if (ret != LTTNG_OK) {
 687                         goto end;
 688                 }
 689
 690                 /* Get next duplicate agent event by name. */
 691                 agent_event_next_duplicate(event_name, agt, &iter);
 692                 node = lttng_ht_iter_get_node_str(&iter);
 693         } while (node);
 694 end:
 695         rcu_read_unlock();
 696         return ret;
 697 }
 698 /*
 699  * Disable all agent event for a given UST session.
 700  *
 701  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 702  */
 703 int event_agent_disable_all(struct ltt_ust_session *usess,
 704                 struct agent *agt)
 705 {
 706         int ret;
 707         struct agent_event *aevent;
 708         struct lttng_ht_iter iter;
 709
 710         assert(agt);
 711         assert(usess);
 712
 713         /*
 714          * Disable event on agent application. Continue to disable all other events
 715          * if the * event is not found.
 716          */
 717         ret = event_agent_disable(usess, agt, "*");
 718         if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_NOT_FOUND) {
 719                 goto error;
 720         }
 721
 722         /* Disable every event. */
 723         rcu_read_lock();
 724         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 725                         node.node) {
 726                 if (!aevent->enabled) {
 727                         continue;
 728                 }
 729
 730                 ret = event_agent_disable(usess, agt, aevent->name);
 731                 if (ret != LTTNG_OK) {
 732                         goto error_unlock;
 733                 }
 734         }
 735         ret = LTTNG_OK;
 736
 737 error_unlock:
 738         rcu_read_unlock();
 739 error:
 740         return ret;
 741 }