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 "ust-ctl.h"
  35 #include "ust-app.h"
  36 #include "trace-kernel.h"
  37 #include "trace-ust.h"
  38 #include "agent.h"
  39
  40 /*
  41  * Add unique UST event based on the event name, filter bytecode and loglevel.
  42  */
  43 static void add_unique_ust_event(struct lttng_ht *ht,
  44                 struct ltt_ust_event *event)
  45 {
  46         struct cds_lfht_node *node_ptr;
  47         struct ltt_ust_ht_key key;
  48
  49         assert(ht);
  50         assert(ht->ht);
  51         assert(event);
  52
  53         key.name = event->attr.name;
  54         key.filter = (struct lttng_filter_bytecode *) event->filter;
  55         key.loglevel_type = event->attr.loglevel_type;
  56         key.loglevel_value = event->attr.loglevel;
  57         key.exclusion = event->exclusion;
  58
  59         node_ptr = cds_lfht_add_unique(ht->ht,
  60                         ht->hash_fct(event->node.key, lttng_ht_seed),
  61                         trace_ust_ht_match_event, &key, &event->node.node);
  62         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                 char *event_name, enum lttng_event_type type)
  73 {
  74         int ret, error = 0, found = 0;
  75         struct ltt_kernel_event *kevent;
  76
  77         assert(kchan);
  78
  79         /* For each event in the kernel session */
  80         cds_list_for_each_entry(kevent, &kchan->events_list.head, list) {
  81                 if (type != LTTNG_EVENT_ALL && kevent->type != type)
  82                         continue;
  83                 if (event_name != NULL && strcmp(event_name, kevent->event->name)) {
  84                         continue;
  85                 }
  86                 found++;
  87                 ret = kernel_disable_event(kevent);
  88                 if (ret < 0) {
  89                         error = 1;
  90                         continue;
  91                 }
  92         }
  93         DBG("Disable kernel event: found %d events with name: %s and type: %d",
  94                         found, event_name ? event_name : "NULL", type);
  95
  96         if (event_name != NULL && !found) {
  97                 ret = LTTNG_ERR_NO_EVENT;
  98         } else {
  99                 ret = error ? LTTNG_ERR_KERN_DISABLE_FAIL : LTTNG_OK;
 100         }
 101
 102         return ret;
 103 }
 104
 105 /*
 106  * Enable kernel tracepoint event for a channel from the kernel session.
 107  * We own filter_expression and filter.
 108  */
 109 int event_kernel_enable_event(struct ltt_kernel_channel *kchan,
 110                 struct lttng_event *event, char *filter_expression,
 111                 struct lttng_filter_bytecode *filter)
 112 {
 113         int ret;
 114         struct ltt_kernel_event *kevent;
 115
 116         assert(kchan);
 117         assert(event);
 118
 119         kevent = trace_kernel_find_event(event->name, kchan,
 120                         event->type, filter);
 121         if (kevent == NULL) {
 122                 ret = kernel_create_event(event, kchan, filter_expression, filter);
 123                 /* We have passed ownership */
 124                 filter_expression = NULL;
 125                 filter = NULL;
 126                 if (ret) {
 127                         goto end;
 128                 }
 129         } else if (kevent->enabled == 0) {
 130                 ret = kernel_enable_event(kevent);
 131                 if (ret < 0) {
 132                         ret = LTTNG_ERR_KERN_ENABLE_FAIL;
 133                         goto end;
 134                 }
 135         } else {
 136                 /* At this point, the event is considered enabled */
 137                 ret = LTTNG_ERR_KERN_EVENT_EXIST;
 138                 goto end;
 139         }
 140
 141         ret = LTTNG_OK;
 142 end:
 143         free(filter_expression);
 144         free(filter);
 145         return ret;
 146 }
 147
 148 /*
 149  * ============================
 150  * UST : The Ultimate Frontier!
 151  * ============================
 152  */
 153
 154 /*
 155  * Enable UST tracepoint event for a channel from a UST session.
 156  * We own filter_expression, filter, and exclusion.
 157  */
 158 int event_ust_enable_tracepoint(struct ltt_ust_session *usess,
 159                 struct ltt_ust_channel *uchan, struct lttng_event *event,
 160                 char *filter_expression,
 161                 struct lttng_filter_bytecode *filter,
 162                 struct lttng_event_exclusion *exclusion,
 163                 bool internal_event)
 164 {
 165         int ret = LTTNG_OK, to_create = 0;
 166         struct ltt_ust_event *uevent;
 167
 168         assert(usess);
 169         assert(uchan);
 170         assert(event);
 171
 172         rcu_read_lock();
 173
 174         uevent = trace_ust_find_event(uchan->events, event->name, filter,
 175                         event->loglevel_type, event->loglevel, exclusion);
 176         if (!uevent) {
 177                 uevent = trace_ust_create_event(event, filter_expression,
 178                                 filter, exclusion, internal_event);
 179                 /* We have passed ownership */
 180                 filter_expression = NULL;
 181                 filter = NULL;
 182                 exclusion = NULL;
 183                 if (uevent == NULL) {
 184                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 185                         goto error;
 186                 }
 187
 188                 /* Valid to set it after the goto error since uevent is still NULL */
 189                 to_create = 1;
 190         }
 191
 192         if (uevent->enabled) {
 193                 /* It's already enabled so everything is OK */
 194                 ret = LTTNG_ERR_UST_EVENT_ENABLED;
 195                 goto end;
 196         }
 197
 198         uevent->enabled = 1;
 199
 200         if (to_create) {
 201                 /* Create event on all UST registered apps for session */
 202                 ret = ust_app_create_event_glb(usess, uchan, uevent);
 203         } else {
 204                 /* Enable event on all UST registered apps for session */
 205                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 206         }
 207
 208         if (ret < 0) {
 209                 if (ret == -LTTNG_UST_ERR_EXIST) {
 210                         ret = LTTNG_ERR_UST_EVENT_EXIST;
 211                         goto end;
 212                 } else {
 213                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 214                         goto error;
 215                 }
 216         }
 217
 218         if (to_create) {
 219                 /* Add ltt ust event to channel */
 220                 add_unique_ust_event(uchan->events, uevent);
 221         }
 222
 223         DBG("Event UST %s %s in channel %s", uevent->attr.name,
 224                         to_create ? "created" : "enabled", uchan->name);
 225
 226         ret = LTTNG_OK;
 227
 228 end:
 229         rcu_read_unlock();
 230         free(filter_expression);
 231         free(filter);
 232         free(exclusion);
 233         return ret;
 234
 235 error:
 236         /*
 237          * Only destroy event on creation time (not enabling time) because if the
 238          * event is found in the channel (to_create == 0), it means that at some
 239          * point the enable_event worked and it's thus valid to keep it alive.
 240          * Destroying it also implies that we also destroy it's shadow copy to sync
 241          * everyone up.
 242          */
 243         if (to_create) {
 244                 /* In this code path, the uevent was not added to the hash table */
 245                 trace_ust_destroy_event(uevent);
 246         }
 247         rcu_read_unlock();
 248         free(filter_expression);
 249         free(filter);
 250         free(exclusion);
 251         return ret;
 252 }
 253
 254 /*
 255  * Disable UST tracepoint of a channel from a UST session.
 256  */
 257 int event_ust_disable_tracepoint(struct ltt_ust_session *usess,
 258                 struct ltt_ust_channel *uchan, char *event_name)
 259 {
 260         int ret;
 261         struct ltt_ust_event *uevent;
 262         struct lttng_ht_node_str *node;
 263         struct lttng_ht_iter iter;
 264         struct lttng_ht *ht;
 265
 266         assert(usess);
 267         assert(uchan);
 268         assert(event_name);
 269
 270         ht = uchan->events;
 271
 272         rcu_read_lock();
 273
 274         /*
 275          * We use a custom lookup since we need the iterator for the next_duplicate
 276          * call in the do while loop below.
 277          */
 278         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) event_name, lttng_ht_seed),
 279                         trace_ust_ht_match_event_by_name, event_name, &iter.iter);
 280         node = lttng_ht_iter_get_node_str(&iter);
 281         if (node == NULL) {
 282                 DBG2("Trace UST event NOT found by name %s", event_name);
 283                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 284                 goto error;
 285         }
 286
 287         do {
 288                 uevent = caa_container_of(node, struct ltt_ust_event, node);
 289                 assert(uevent);
 290
 291                 if (uevent->enabled == 0) {
 292                         /* It's already disabled so everything is OK */
 293                         goto next;
 294                 }
 295
 296                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 297                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 298                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 299                         goto error;
 300                 }
 301                 uevent->enabled = 0;
 302
 303                 DBG2("Event UST %s disabled in channel %s", uevent->attr.name,
 304                                 uchan->name);
 305
 306 next:
 307                 /* Get next duplicate event by name. */
 308                 cds_lfht_next_duplicate(ht->ht, trace_ust_ht_match_event_by_name,
 309                                 event_name, &iter.iter);
 310                 node = lttng_ht_iter_get_node_str(&iter);
 311         } while (node);
 312
 313         ret = LTTNG_OK;
 314
 315 error:
 316         rcu_read_unlock();
 317         return ret;
 318 }
 319
 320 /*
 321  * Disable all UST tracepoints for a channel from a UST session.
 322  */
 323 int event_ust_disable_all_tracepoints(struct ltt_ust_session *usess,
 324                 struct ltt_ust_channel *uchan)
 325 {
 326         int ret, i, size, error = 0;
 327         struct lttng_ht_iter iter;
 328         struct ltt_ust_event *uevent = NULL;
 329         struct lttng_event *events = NULL;
 330
 331         assert(usess);
 332         assert(uchan);
 333
 334         rcu_read_lock();
 335
 336         /* Disabling existing events */
 337         cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 338                         node.node) {
 339                 if (uevent->enabled == 1) {
 340                         ret = event_ust_disable_tracepoint(usess, uchan,
 341                                         uevent->attr.name);
 342                         if (ret < 0) {
 343                                 error = LTTNG_ERR_UST_DISABLE_FAIL;
 344                                 continue;
 345                         }
 346                 }
 347         }
 348
 349         /* Get all UST available events */
 350         size = ust_app_list_events(&events);
 351         if (size < 0) {
 352                 ret = LTTNG_ERR_UST_LIST_FAIL;
 353                 goto error;
 354         }
 355
 356         for (i = 0; i < size; i++) {
 357                 ret = event_ust_disable_tracepoint(usess, uchan,
 358                                 events[i].name);
 359                 if (ret < 0) {
 360                         /* Continue to disable the rest... */
 361                         error = LTTNG_ERR_UST_DISABLE_FAIL;
 362                         continue;
 363                 }
 364         }
 365
 366         ret = error ? error : LTTNG_OK;
 367 error:
 368         rcu_read_unlock();
 369         free(events);
 370         return ret;
 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, struct lttng_event *event,
 380                 struct lttng_filter_bytecode *filter ,char *filter_expression)
 381 {
 382         int ret;
 383         struct agent_event *aevent;
 384         struct lttng_ht_iter iter;
 385
 386         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         /* Flag every event that they are now enabled. */
 397         rcu_read_lock();
 398         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 399                         node.node) {
 400                 aevent->enabled = 1;
 401         }
 402         rcu_read_unlock();
 403
 404         ret = LTTNG_OK;
 405
 406 error:
 407         return ret;
 408 }
 409
 410 /*
 411  * Check if this event's filter requires the activation of application contexts
 412  * and enable them in the agent.
 413  * TODO: bytecode iterator does not support non-legacy application
 414  * contexts yet. Not an issue for now, since they are not generated by
 415  * the lttng-ctl library.
 416  */
 417 static int add_filter_app_ctx(struct lttng_filter_bytecode *bytecode,
 418                 const char *filter_expression, struct agent *agt)
 419 {
 420         int ret = LTTNG_OK;
 421         char *provider_name = NULL, *ctx_name = NULL;
 422         struct bytecode_symbol_iterator *it =
 423                         bytecode_symbol_iterator_create(bytecode);
 424
 425         if (!it) {
 426                 ret = LTTNG_ERR_NOMEM;
 427                 goto end;
 428         }
 429
 430         do {
 431                 struct lttng_event_context ctx;
 432                 const char *symbol_name =
 433                                 bytecode_symbol_iterator_get_name(it);
 434
 435                 if (parse_application_context(symbol_name, &provider_name,
 436                                 &ctx_name)) {
 437                         /* Not an application context. */
 438                         continue;
 439                 }
 440
 441                 ctx.ctx = LTTNG_EVENT_CONTEXT_APP_CONTEXT;
 442                 ctx.u.app_ctx.provider_name = provider_name;
 443                 ctx.u.app_ctx.ctx_name = ctx_name;
 444
 445                 /* Recognized an application context. */
 446                 DBG("Enabling event with filter expression \"%s\" requires enabling the %s:%s application context.",
 447                                 filter_expression, provider_name, ctx_name);
 448
 449                 ret = agent_add_context(&ctx, agt);
 450                 if (ret != LTTNG_OK) {
 451                         ERR("Failed to add application context %s:%s.",
 452                                         provider_name, ctx_name);
 453                         goto end;
 454                 }
 455
 456                 ret = agent_enable_context(&ctx, agt->domain);
 457                 if (ret != LTTNG_OK) {
 458                         ERR("Failed to enable application context %s:%s.",
 459                                         provider_name, ctx_name);
 460                         goto end;
 461                 }
 462
 463                 free(provider_name);
 464                 free(ctx_name);
 465                 provider_name = ctx_name = NULL;
 466         } while (bytecode_symbol_iterator_next(it) == 0);
 467 end:
 468         free(provider_name);
 469         free(ctx_name);
 470         bytecode_symbol_iterator_destroy(it);
 471         return ret;
 472 }
 473
 474 /*
 475  * Enable a single agent event for a given UST session.
 476  *
 477  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 478  */
 479 int event_agent_enable(struct ltt_ust_session *usess,
 480                 struct agent *agt, struct lttng_event *event,
 481                 struct lttng_filter_bytecode *filter,
 482                 char *filter_expression)
 483 {
 484         int ret, created = 0;
 485         struct agent_event *aevent;
 486
 487         assert(usess);
 488         assert(event);
 489         assert(agt);
 490
 491         DBG("Event agent enabling %s for session %" PRIu64 " with loglevel type %d "
 492                         ", loglevel %d and filter \"%s\"", event->name,
 493                         usess->id, event->loglevel_type, event->loglevel,
 494                         filter_expression ? filter_expression : "NULL");
 495
 496         aevent = agent_find_event(event->name, event->loglevel_type,
 497                         event->loglevel, filter_expression, agt);
 498         if (!aevent) {
 499                 aevent = agent_create_event(event->name, event->loglevel_type,
 500                                 event->loglevel, filter,
 501                                 filter_expression);
 502                 if (!aevent) {
 503                         ret = LTTNG_ERR_NOMEM;
 504                         goto error;
 505                 }
 506
 507                 created = 1;
 508         }
 509
 510         /* Already enabled? */
 511         if (aevent->enabled) {
 512                 goto end;
 513         }
 514
 515         if (created && filter) {
 516                 ret = add_filter_app_ctx(filter, filter_expression, agt);
 517                 if (ret != LTTNG_OK) {
 518                         goto error;
 519                 }
 520         }
 521
 522         ret = agent_enable_event(aevent, agt->domain);
 523         if (ret != LTTNG_OK) {
 524                 goto error;
 525         }
 526
 527         /* If the event was created prior to the enable, add it to the domain. */
 528         if (created) {
 529                 agent_add_event(aevent, agt);
 530         }
 531
 532 end:
 533         return LTTNG_OK;
 534
 535 error:
 536         if (created) {
 537                 agent_destroy_event(aevent);
 538         }
 539         return ret;
 540 }
 541
 542 /*
 543  * Return the default event name associated with the provided UST domain. Return
 544  * NULL on error.
 545  */
 546 const char *event_get_default_agent_ust_name(enum lttng_domain_type domain)
 547 {
 548         const char *default_event_name = NULL;
 549
 550         switch (domain) {
 551         case LTTNG_DOMAIN_LOG4J:
 552                 default_event_name = DEFAULT_LOG4J_EVENT_NAME;
 553                 break;
 554         case LTTNG_DOMAIN_JUL:
 555                 default_event_name = DEFAULT_JUL_EVENT_NAME;
 556                 break;
 557         case LTTNG_DOMAIN_PYTHON:
 558                 default_event_name = DEFAULT_PYTHON_EVENT_NAME;
 559                 break;
 560         default:
 561                 assert(0);
 562         }
 563
 564         return default_event_name;
 565 }
 566
 567 /*
 568  * Disable a given agent event for a given UST session.
 569  *
 570  * Must be called with the RCU read lock held.
 571  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 572  */
 573 static int event_agent_disable_one(struct ltt_ust_session *usess,
 574                 struct agent *agt, struct agent_event *aevent)
 575 {
 576         int ret;
 577         struct ltt_ust_event *uevent = NULL;
 578         struct ltt_ust_channel *uchan = NULL;
 579         const char *ust_event_name, *ust_channel_name;
 580
 581         assert(agt);
 582         assert(usess);
 583         assert(aevent);
 584
 585         DBG("Event agent disabling %s (loglevel type %d, loglevel value %d) for session %" PRIu64,
 586                 aevent->name, aevent->loglevel_type, aevent->loglevel_value,
 587                 usess->id);
 588
 589         /* Already disabled? */
 590         if (!aevent->enabled) {
 591                 goto end;
 592         }
 593
 594         if (agt->domain == LTTNG_DOMAIN_JUL) {
 595                 ust_channel_name = DEFAULT_JUL_CHANNEL_NAME;
 596         } else if (agt->domain == LTTNG_DOMAIN_LOG4J) {
 597                 ust_channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
 598         } else if (agt->domain == LTTNG_DOMAIN_PYTHON) {
 599                 ust_channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
 600         } else {
 601                 ret = LTTNG_ERR_INVALID;
 602                 goto error;
 603         }
 604
 605         /*
 606          * Disable it on the UST side. First get the channel reference then find
 607          * the event and finally disable it.
 608          */
 609         uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 610                         (char *) ust_channel_name);
 611         if (!uchan) {
 612                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 613                 goto error;
 614         }
 615
 616         ust_event_name = event_get_default_agent_ust_name(agt->domain);
 617         if (!ust_event_name) {
 618                 ret = LTTNG_ERR_FATAL;
 619                 goto error;
 620         }
 621
 622         /*
 623          * Agent UST event has its loglevel type forced to
 624          * LTTNG_UST_LOGLEVEL_ALL. The actual loglevel type/value filtering
 625          * happens thanks to an UST filter. The following -1 is actually
 626          * ignored since the type is LTTNG_UST_LOGLEVEL_ALL.
 627          */
 628         uevent = trace_ust_find_event(uchan->events, (char *) ust_event_name,
 629                         aevent->filter, LTTNG_UST_LOGLEVEL_ALL, -1, NULL);
 630         /* If the agent event exists, it must be available on the UST side. */
 631         assert(uevent);
 632
 633         ret = ust_app_disable_event_glb(usess, uchan, uevent);
 634         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 635                 ret = LTTNG_ERR_UST_DISABLE_FAIL;
 636                 goto error;
 637         }
 638
 639         /*
 640          * Flag event that it's disabled so the shadow copy on the ust app side
 641          * will disable it if an application shows up.
 642          */
 643         uevent->enabled = 0;
 644
 645         ret = agent_disable_event(aevent, agt->domain);
 646         if (ret != LTTNG_OK) {
 647                 goto error;
 648         }
 649
 650 end:
 651         return LTTNG_OK;
 652
 653 error:
 654         return ret;
 655 }
 656
 657 /*
 658  * Disable all agent events matching a given name for a given UST session.
 659  *
 660  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 661  */
 662 int event_agent_disable(struct ltt_ust_session *usess, struct agent *agt,
 663                 char *event_name)
 664 {
 665         int ret = LTTNG_OK;
 666         struct agent_event *aevent;
 667         struct lttng_ht_iter iter;
 668         struct lttng_ht_node_str *node;
 669
 670         assert(agt);
 671         assert(usess);
 672         assert(event_name);
 673
 674         DBG("Event agent disabling %s (all loglevels) for session %" PRIu64, event_name, usess->id);
 675
 676         rcu_read_lock();
 677         agent_find_events_by_name(event_name, agt, &iter);
 678         node = lttng_ht_iter_get_node_str(&iter);
 679
 680         if (node == NULL) {
 681                 DBG2("Event agent NOT found by name %s", event_name);
 682                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 683                 goto end;
 684         }
 685
 686         do {
 687                 aevent = caa_container_of(node, struct agent_event, node);
 688                 ret = event_agent_disable_one(usess, agt, aevent);
 689
 690                 if (ret != LTTNG_OK) {
 691                         goto end;
 692                 }
 693
 694                 /* Get next duplicate agent event by name. */
 695                 agent_event_next_duplicate(event_name, agt, &iter);
 696                 node = lttng_ht_iter_get_node_str(&iter);
 697         } while (node);
 698 end:
 699         rcu_read_unlock();
 700         return ret;
 701 }
 702 /*
 703  * Disable all agent event for a given UST session.
 704  *
 705  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 706  */
 707 int event_agent_disable_all(struct ltt_ust_session *usess,
 708                 struct agent *agt)
 709 {
 710         int ret;
 711         struct agent_event *aevent;
 712         struct lttng_ht_iter iter;
 713
 714         assert(agt);
 715         assert(usess);
 716
 717         /*
 718          * Disable event on agent application. Continue to disable all other events
 719          * if the * event is not found.
 720          */
 721         ret = event_agent_disable(usess, agt, "*");
 722         if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_NOT_FOUND) {
 723                 goto error;
 724         }
 725
 726         /* Disable every event. */
 727         rcu_read_lock();
 728         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 729                         node.node) {
 730                 if (!aevent->enabled) {
 731                         continue;
 732                 }
 733
 734                 ret = event_agent_disable(usess, agt, aevent->name);
 735                 if (ret != LTTNG_OK) {
 736                         goto error_unlock;
 737                 }
 738         }
 739         ret = LTTNG_OK;
 740
 741 error_unlock:
 742         rcu_read_unlock();
 743 error:
 744         return ret;
 745 }