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, 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                 ret = trace_ust_create_event(event, filter_expression,
 178                                 filter, exclusion, internal_event, &uevent);
 179                 /* We have passed ownership */
 180                 filter_expression = NULL;
 181                 filter = NULL;
 182                 exclusion = NULL;
 183                 if (ret != LTTNG_OK) {
 184                         goto error;
 185                 }
 186
 187                 /* Valid to set it after the goto error since uevent is still NULL */
 188                 to_create = 1;
 189         }
 190
 191         if (uevent->enabled) {
 192                 /* It's already enabled so everything is OK */
 193                 ret = LTTNG_ERR_UST_EVENT_ENABLED;
 194                 goto end;
 195         }
 196
 197         uevent->enabled = 1;
 198
 199         if (to_create) {
 200                 /* Create event on all UST registered apps for session */
 201                 ret = ust_app_create_event_glb(usess, uchan, uevent);
 202         } else {
 203                 /* Enable event on all UST registered apps for session */
 204                 ret = ust_app_enable_event_glb(usess, uchan, uevent);
 205         }
 206
 207         if (ret < 0) {
 208                 if (ret == -LTTNG_UST_ERR_EXIST) {
 209                         ret = LTTNG_ERR_UST_EVENT_EXIST;
 210                         goto end;
 211                 } else {
 212                         ret = LTTNG_ERR_UST_ENABLE_FAIL;
 213                         goto error;
 214                 }
 215         }
 216
 217         if (to_create) {
 218                 /* Add ltt ust event to channel */
 219                 add_unique_ust_event(uchan->events, uevent);
 220         }
 221
 222         DBG("Event UST %s %s in channel %s", uevent->attr.name,
 223                         to_create ? "created" : "enabled", uchan->name);
 224
 225         ret = LTTNG_OK;
 226
 227 end:
 228         rcu_read_unlock();
 229         free(filter_expression);
 230         free(filter);
 231         free(exclusion);
 232         return ret;
 233
 234 error:
 235         /*
 236          * Only destroy event on creation time (not enabling time) because if the
 237          * event is found in the channel (to_create == 0), it means that at some
 238          * point the enable_event worked and it's thus valid to keep it alive.
 239          * Destroying it also implies that we also destroy it's shadow copy to sync
 240          * everyone up.
 241          */
 242         if (to_create) {
 243                 /* In this code path, the uevent was not added to the hash table */
 244                 trace_ust_destroy_event(uevent);
 245         }
 246         rcu_read_unlock();
 247         free(filter_expression);
 248         free(filter);
 249         free(exclusion);
 250         return ret;
 251 }
 252
 253 /*
 254  * Disable UST tracepoint of a channel from a UST session.
 255  */
 256 int event_ust_disable_tracepoint(struct ltt_ust_session *usess,
 257                 struct ltt_ust_channel *uchan, char *event_name)
 258 {
 259         int ret;
 260         struct ltt_ust_event *uevent;
 261         struct lttng_ht_node_str *node;
 262         struct lttng_ht_iter iter;
 263         struct lttng_ht *ht;
 264
 265         assert(usess);
 266         assert(uchan);
 267         assert(event_name);
 268
 269         ht = uchan->events;
 270
 271         rcu_read_lock();
 272
 273         /*
 274          * We use a custom lookup since we need the iterator for the next_duplicate
 275          * call in the do while loop below.
 276          */
 277         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) event_name, lttng_ht_seed),
 278                         trace_ust_ht_match_event_by_name, event_name, &iter.iter);
 279         node = lttng_ht_iter_get_node_str(&iter);
 280         if (node == NULL) {
 281                 DBG2("Trace UST event NOT found by name %s", event_name);
 282                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 283                 goto error;
 284         }
 285
 286         do {
 287                 uevent = caa_container_of(node, struct ltt_ust_event, node);
 288                 assert(uevent);
 289
 290                 if (uevent->enabled == 0) {
 291                         /* It's already disabled so everything is OK */
 292                         goto next;
 293                 }
 294
 295                 ret = ust_app_disable_event_glb(usess, uchan, uevent);
 296                 if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 297                         ret = LTTNG_ERR_UST_DISABLE_FAIL;
 298                         goto error;
 299                 }
 300                 uevent->enabled = 0;
 301
 302                 DBG2("Event UST %s disabled in channel %s", uevent->attr.name,
 303                                 uchan->name);
 304
 305 next:
 306                 /* Get next duplicate event by name. */
 307                 cds_lfht_next_duplicate(ht->ht, trace_ust_ht_match_event_by_name,
 308                                 event_name, &iter.iter);
 309                 node = lttng_ht_iter_get_node_str(&iter);
 310         } while (node);
 311
 312         ret = LTTNG_OK;
 313
 314 error:
 315         rcu_read_unlock();
 316         return ret;
 317 }
 318
 319 /*
 320  * Disable all UST tracepoints for a channel from a UST session.
 321  */
 322 int event_ust_disable_all_tracepoints(struct ltt_ust_session *usess,
 323                 struct ltt_ust_channel *uchan)
 324 {
 325         int ret, i, size, error = 0;
 326         struct lttng_ht_iter iter;
 327         struct ltt_ust_event *uevent = NULL;
 328         struct lttng_event *events = NULL;
 329
 330         assert(usess);
 331         assert(uchan);
 332
 333         rcu_read_lock();
 334
 335         /* Disabling existing events */
 336         cds_lfht_for_each_entry(uchan->events->ht, &iter.iter, uevent,
 337                         node.node) {
 338                 if (uevent->enabled == 1) {
 339                         ret = event_ust_disable_tracepoint(usess, uchan,
 340                                         uevent->attr.name);
 341                         if (ret < 0) {
 342                                 error = LTTNG_ERR_UST_DISABLE_FAIL;
 343                                 continue;
 344                         }
 345                 }
 346         }
 347
 348         /* Get all UST available events */
 349         size = ust_app_list_events(&events);
 350         if (size < 0) {
 351                 ret = LTTNG_ERR_UST_LIST_FAIL;
 352                 goto error;
 353         }
 354
 355         for (i = 0; i < size; i++) {
 356                 ret = event_ust_disable_tracepoint(usess, uchan,
 357                                 events[i].name);
 358                 if (ret < 0) {
 359                         /* Continue to disable the rest... */
 360                         error = LTTNG_ERR_UST_DISABLE_FAIL;
 361                         continue;
 362                 }
 363         }
 364
 365         ret = error ? error : LTTNG_OK;
 366 error:
 367         rcu_read_unlock();
 368         free(events);
 369         return ret;
 370 }
 371
 372 /*
 373  * Enable all agent event for a given UST session.
 374  *
 375  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 376  */
 377 int event_agent_enable_all(struct ltt_ust_session *usess,
 378                 struct agent *agt, struct lttng_event *event,
 379                 struct lttng_filter_bytecode *filter ,char *filter_expression)
 380 {
 381         int ret;
 382         struct agent_event *aevent;
 383         struct lttng_ht_iter iter;
 384
 385         assert(usess);
 386
 387         DBG("Event agent enabling ALL events for session %" PRIu64, usess->id);
 388
 389         /* Enable event on agent application through TCP socket. */
 390         ret = event_agent_enable(usess, agt, event, filter, filter_expression);
 391         if (ret != LTTNG_OK) {
 392                 goto error;
 393         }
 394
 395         /* Flag every event that they are now enabled. */
 396         rcu_read_lock();
 397         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 398                         node.node) {
 399                 aevent->enabled = 1;
 400         }
 401         rcu_read_unlock();
 402
 403         ret = LTTNG_OK;
 404
 405 error:
 406         return ret;
 407 }
 408
 409 /*
 410  * Check if this event's filter requires the activation of application contexts
 411  * and enable them in the agent.
 412  * TODO: bytecode iterator does not support non-legacy application
 413  * contexts yet. Not an issue for now, since they are not generated by
 414  * the lttng-ctl library.
 415  */
 416 static int add_filter_app_ctx(struct lttng_filter_bytecode *bytecode,
 417                 const char *filter_expression, struct agent *agt)
 418 {
 419         int ret = LTTNG_OK;
 420         char *provider_name = NULL, *ctx_name = NULL;
 421         struct bytecode_symbol_iterator *it =
 422                         bytecode_symbol_iterator_create(bytecode);
 423
 424         if (!it) {
 425                 ret = LTTNG_ERR_NOMEM;
 426                 goto end;
 427         }
 428
 429         do {
 430                 struct lttng_event_context ctx;
 431                 const char *symbol_name =
 432                                 bytecode_symbol_iterator_get_name(it);
 433
 434                 if (parse_application_context(symbol_name, &provider_name,
 435                                 &ctx_name)) {
 436                         /* Not an application context. */
 437                         continue;
 438                 }
 439
 440                 ctx.ctx = LTTNG_EVENT_CONTEXT_APP_CONTEXT;
 441                 ctx.u.app_ctx.provider_name = provider_name;
 442                 ctx.u.app_ctx.ctx_name = ctx_name;
 443
 444                 /* Recognized an application context. */
 445                 DBG("Enabling event with filter expression \"%s\" requires enabling the %s:%s application context.",
 446                                 filter_expression, provider_name, ctx_name);
 447
 448                 ret = agent_add_context(&ctx, agt);
 449                 if (ret != LTTNG_OK) {
 450                         ERR("Failed to add application context %s:%s.",
 451                                         provider_name, ctx_name);
 452                         goto end;
 453                 }
 454
 455                 ret = agent_enable_context(&ctx, agt->domain);
 456                 if (ret != LTTNG_OK) {
 457                         ERR("Failed to enable application context %s:%s.",
 458                                         provider_name, ctx_name);
 459                         goto end;
 460                 }
 461
 462                 free(provider_name);
 463                 free(ctx_name);
 464                 provider_name = ctx_name = NULL;
 465         } while (bytecode_symbol_iterator_next(it) == 0);
 466 end:
 467         free(provider_name);
 468         free(ctx_name);
 469         bytecode_symbol_iterator_destroy(it);
 470         return ret;
 471 }
 472
 473 /*
 474  * Enable a single agent event for a given UST session.
 475  *
 476  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 477  */
 478 int event_agent_enable(struct ltt_ust_session *usess,
 479                 struct agent *agt, struct lttng_event *event,
 480                 struct lttng_filter_bytecode *filter,
 481                 char *filter_expression)
 482 {
 483         int ret, created = 0;
 484         struct agent_event *aevent;
 485
 486         assert(usess);
 487         assert(event);
 488         assert(agt);
 489
 490         DBG("Event agent enabling %s for session %" PRIu64 " with loglevel type %d "
 491                         ", loglevel %d and filter \"%s\"", event->name,
 492                         usess->id, event->loglevel_type, event->loglevel,
 493                         filter_expression ? filter_expression : "NULL");
 494
 495         aevent = agent_find_event(event->name, event->loglevel_type,
 496                         event->loglevel, filter_expression, agt);
 497         if (!aevent) {
 498                 aevent = agent_create_event(event->name, event->loglevel_type,
 499                                 event->loglevel, filter,
 500                                 filter_expression);
 501                 if (!aevent) {
 502                         ret = LTTNG_ERR_NOMEM;
 503                         goto error;
 504                 }
 505
 506                 created = 1;
 507         }
 508
 509         /* Already enabled? */
 510         if (aevent->enabled) {
 511                 goto end;
 512         }
 513
 514         if (created && filter) {
 515                 ret = add_filter_app_ctx(filter, filter_expression, agt);
 516                 if (ret != LTTNG_OK) {
 517                         goto error;
 518                 }
 519         }
 520
 521         ret = agent_enable_event(aevent, agt->domain);
 522         if (ret != LTTNG_OK) {
 523                 goto error;
 524         }
 525
 526         /* If the event was created prior to the enable, add it to the domain. */
 527         if (created) {
 528                 agent_add_event(aevent, agt);
 529         }
 530
 531 end:
 532         return LTTNG_OK;
 533
 534 error:
 535         if (created) {
 536                 agent_destroy_event(aevent);
 537         }
 538         return ret;
 539 }
 540
 541 /*
 542  * Return the default event name associated with the provided UST domain. Return
 543  * NULL on error.
 544  */
 545 const char *event_get_default_agent_ust_name(enum lttng_domain_type domain)
 546 {
 547         const char *default_event_name = NULL;
 548
 549         switch (domain) {
 550         case LTTNG_DOMAIN_LOG4J:
 551                 default_event_name = DEFAULT_LOG4J_EVENT_NAME;
 552                 break;
 553         case LTTNG_DOMAIN_JUL:
 554                 default_event_name = DEFAULT_JUL_EVENT_NAME;
 555                 break;
 556         case LTTNG_DOMAIN_PYTHON:
 557                 default_event_name = DEFAULT_PYTHON_EVENT_NAME;
 558                 break;
 559         default:
 560                 assert(0);
 561         }
 562
 563         return default_event_name;
 564 }
 565
 566 /*
 567  * Disable a given agent event for a given UST session.
 568  *
 569  * Must be called with the RCU read lock held.
 570  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 571  */
 572 static int event_agent_disable_one(struct ltt_ust_session *usess,
 573                 struct agent *agt, struct agent_event *aevent)
 574 {
 575         int ret;
 576         struct ltt_ust_event *uevent = NULL;
 577         struct ltt_ust_channel *uchan = NULL;
 578         const char *ust_event_name, *ust_channel_name;
 579
 580         assert(agt);
 581         assert(usess);
 582         assert(aevent);
 583
 584         DBG("Event agent disabling %s (loglevel type %d, loglevel value %d) for session %" PRIu64,
 585                 aevent->name, aevent->loglevel_type, aevent->loglevel_value,
 586                 usess->id);
 587
 588         /* Already disabled? */
 589         if (!aevent->enabled) {
 590                 goto end;
 591         }
 592
 593         if (agt->domain == LTTNG_DOMAIN_JUL) {
 594                 ust_channel_name = DEFAULT_JUL_CHANNEL_NAME;
 595         } else if (agt->domain == LTTNG_DOMAIN_LOG4J) {
 596                 ust_channel_name = DEFAULT_LOG4J_CHANNEL_NAME;
 597         } else if (agt->domain == LTTNG_DOMAIN_PYTHON) {
 598                 ust_channel_name = DEFAULT_PYTHON_CHANNEL_NAME;
 599         } else {
 600                 ret = LTTNG_ERR_INVALID;
 601                 goto error;
 602         }
 603
 604         /*
 605          * Disable it on the UST side. First get the channel reference then find
 606          * the event and finally disable it.
 607          */
 608         uchan = trace_ust_find_channel_by_name(usess->domain_global.channels,
 609                         (char *) ust_channel_name);
 610         if (!uchan) {
 611                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 612                 goto error;
 613         }
 614
 615         ust_event_name = event_get_default_agent_ust_name(agt->domain);
 616         if (!ust_event_name) {
 617                 ret = LTTNG_ERR_FATAL;
 618                 goto error;
 619         }
 620
 621         /*
 622          * Agent UST event has its loglevel type forced to
 623          * LTTNG_UST_LOGLEVEL_ALL. The actual loglevel type/value filtering
 624          * happens thanks to an UST filter. The following -1 is actually
 625          * ignored since the type is LTTNG_UST_LOGLEVEL_ALL.
 626          */
 627         uevent = trace_ust_find_event(uchan->events, (char *) ust_event_name,
 628                         aevent->filter, LTTNG_UST_LOGLEVEL_ALL, -1, NULL);
 629         /* If the agent event exists, it must be available on the UST side. */
 630         assert(uevent);
 631
 632         ret = ust_app_disable_event_glb(usess, uchan, uevent);
 633         if (ret < 0 && ret != -LTTNG_UST_ERR_EXIST) {
 634                 ret = LTTNG_ERR_UST_DISABLE_FAIL;
 635                 goto error;
 636         }
 637
 638         /*
 639          * Flag event that it's disabled so the shadow copy on the ust app side
 640          * will disable it if an application shows up.
 641          */
 642         uevent->enabled = 0;
 643
 644         ret = agent_disable_event(aevent, agt->domain);
 645         if (ret != LTTNG_OK) {
 646                 goto error;
 647         }
 648
 649 end:
 650         return LTTNG_OK;
 651
 652 error:
 653         return ret;
 654 }
 655
 656 /*
 657  * Disable all agent events matching a given name for a given UST session.
 658  *
 659  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 660  */
 661 int event_agent_disable(struct ltt_ust_session *usess, struct agent *agt,
 662                 char *event_name)
 663 {
 664         int ret = LTTNG_OK;
 665         struct agent_event *aevent;
 666         struct lttng_ht_iter iter;
 667         struct lttng_ht_node_str *node;
 668
 669         assert(agt);
 670         assert(usess);
 671         assert(event_name);
 672
 673         DBG("Event agent disabling %s (all loglevels) for session %" PRIu64, event_name, usess->id);
 674
 675         rcu_read_lock();
 676         agent_find_events_by_name(event_name, agt, &iter);
 677         node = lttng_ht_iter_get_node_str(&iter);
 678
 679         if (node == NULL) {
 680                 DBG2("Event agent NOT found by name %s", event_name);
 681                 ret = LTTNG_ERR_UST_EVENT_NOT_FOUND;
 682                 goto end;
 683         }
 684
 685         do {
 686                 aevent = caa_container_of(node, struct agent_event, node);
 687                 ret = event_agent_disable_one(usess, agt, aevent);
 688
 689                 if (ret != LTTNG_OK) {
 690                         goto end;
 691                 }
 692
 693                 /* Get next duplicate agent event by name. */
 694                 agent_event_next_duplicate(event_name, agt, &iter);
 695                 node = lttng_ht_iter_get_node_str(&iter);
 696         } while (node);
 697 end:
 698         rcu_read_unlock();
 699         return ret;
 700 }
 701 /*
 702  * Disable all agent event for a given UST session.
 703  *
 704  * Return LTTNG_OK on success or else a LTTNG_ERR* code.
 705  */
 706 int event_agent_disable_all(struct ltt_ust_session *usess,
 707                 struct agent *agt)
 708 {
 709         int ret;
 710         struct agent_event *aevent;
 711         struct lttng_ht_iter iter;
 712
 713         assert(agt);
 714         assert(usess);
 715
 716         /*
 717          * Disable event on agent application. Continue to disable all other events
 718          * if the * event is not found.
 719          */
 720         ret = event_agent_disable(usess, agt, "*");
 721         if (ret != LTTNG_OK && ret != LTTNG_ERR_UST_EVENT_NOT_FOUND) {
 722                 goto error;
 723         }
 724
 725         /* Disable every event. */
 726         rcu_read_lock();
 727         cds_lfht_for_each_entry(agt->events->ht, &iter.iter, aevent,
 728                         node.node) {
 729                 if (!aevent->enabled) {
 730                         continue;
 731                 }
 732
 733                 ret = event_agent_disable(usess, agt, aevent->name);
 734                 if (ret != LTTNG_OK) {
 735                         goto error_unlock;
 736                 }
 737         }
 738         ret = LTTNG_OK;
 739
 740 error_unlock:
 741         rcu_read_unlock();
 742 error:
 743         return ret;
 744 }