liblttng-ust/lttng-events.c

   1 /*
   2  * lttng-events.c
   3  *
   4  * Holds LTTng per-session event registry.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _LGPL_SOURCE
  24 #include <stdio.h>
  25 #include <assert.h>
  26 #include <errno.h>
  27 #include <limits.h>
  28 #include <pthread.h>
  29 #include <sys/shm.h>
  30 #include <sys/ipc.h>
  31 #include <stdint.h>
  32 #include <stddef.h>
  33 #include <inttypes.h>
  34 #include <time.h>
  35 #include <stdbool.h>
  36 #include <unistd.h>
  37 #include <dlfcn.h>
  38 #include <lttng/ust-endian.h>
  39
  40 #include <urcu/arch.h>
  41 #include <urcu/compiler.h>
  42 #include <urcu/hlist.h>
  43 #include <urcu/list.h>
  44 #include <urcu/uatomic.h>
  45
  46 #include <lttng/tracepoint.h>
  47 #include <lttng/ust-events.h>
  48
  49 #include <usterr-signal-safe.h>
  50 #include <helper.h>
  51 #include <lttng/ust-ctl.h>
  52 #include <ust-comm.h>
  53 #include <ust-fd.h>
  54 #include <lttng/ust-dynamic-type.h>
  55 #include <lttng/ust-context-provider.h>
  56 #include "error.h"
  57 #include "compat.h"
  58 #include "lttng-ust-uuid.h"
  59
  60 #include "tracepoint-internal.h"
  61 #include "string-utils.h"
  62 #include "lttng-bytecode.h"
  63 #include "lttng-tracer.h"
  64 #include "lttng-tracer-core.h"
  65 #include "lttng-ust-statedump.h"
  66 #include "context-internal.h"
  67 #include "ust-events-internal.h"
  68 #include "wait.h"
  69 #include "../libringbuffer/shm.h"
  70 #include "../libcounter/counter.h"
  71 #include "jhash.h"
  72 #include <lttng/ust-abi.h>
  73
  74 /*
  75  * All operations within this file are called by the communication
  76  * thread, under ust_lock protection.
  77  */
  78
  79 static CDS_LIST_HEAD(sessions);
  80 static CDS_LIST_HEAD(event_notifier_groups);
  81
  82 struct cds_list_head *_lttng_get_sessions(void)
  83 {
  84         return &sessions;
  85 }
  86
  87 static void _lttng_event_destroy(struct lttng_event *event);
  88 static void _lttng_event_notifier_destroy(
  89                 struct lttng_event_notifier *event_notifier);
  90 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  91
  92 static
  93 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  94 static
  95 void lttng_session_sync_event_enablers(struct lttng_session *session);
  96 static
  97 void lttng_event_notifier_group_sync_enablers(
  98                 struct lttng_event_notifier_group *event_notifier_group);
  99 static
 100 void lttng_enabler_destroy(struct lttng_enabler *enabler);
 101
 102 /*
 103  * Called with ust lock held.
 104  */
 105 int lttng_session_active(void)
 106 {
 107         struct lttng_session *iter;
 108
 109         cds_list_for_each_entry(iter, &sessions, node) {
 110                 if (iter->active)
 111                         return 1;
 112         }
 113         return 0;
 114 }
 115
 116 static
 117 int lttng_loglevel_match(int loglevel,
 118                 unsigned int has_loglevel,
 119                 enum lttng_ust_loglevel_type req_type,
 120                 int req_loglevel)
 121 {
 122         if (!has_loglevel)
 123                 loglevel = TRACE_DEFAULT;
 124         switch (req_type) {
 125         case LTTNG_UST_LOGLEVEL_RANGE:
 126                 if (loglevel <= req_loglevel
 127                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 128                         return 1;
 129                 else
 130                         return 0;
 131         case LTTNG_UST_LOGLEVEL_SINGLE:
 132                 if (loglevel == req_loglevel
 133                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 134                         return 1;
 135                 else
 136                         return 0;
 137         case LTTNG_UST_LOGLEVEL_ALL:
 138         default:
 139                 if (loglevel <= TRACE_DEBUG)
 140                         return 1;
 141                 else
 142                         return 0;
 143         }
 144 }
 145
 146 struct lttng_session *lttng_session_create(void)
 147 {
 148         struct lttng_session *session;
 149         int i;
 150
 151         session = zmalloc(sizeof(struct lttng_session));
 152         if (!session)
 153                 return NULL;
 154         if (lttng_context_init_all(&session->ctx)) {
 155                 free(session);
 156                 return NULL;
 157         }
 158         CDS_INIT_LIST_HEAD(&session->chan_head);
 159         CDS_INIT_LIST_HEAD(&session->events_head);
 160         CDS_INIT_LIST_HEAD(&session->enums_head);
 161         CDS_INIT_LIST_HEAD(&session->enablers_head);
 162         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 163                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 164         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 165                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 166         cds_list_add(&session->node, &sessions);
 167         return session;
 168 }
 169
 170 struct lttng_counter *lttng_ust_counter_create(
 171                 const char *counter_transport_name,
 172                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 173 {
 174         struct lttng_counter_transport *counter_transport = NULL;
 175         struct lttng_counter *counter = NULL;
 176
 177         counter_transport = lttng_counter_transport_find(counter_transport_name);
 178         if (!counter_transport)
 179                 goto notransport;
 180         counter = zmalloc(sizeof(struct lttng_counter));
 181         if (!counter)
 182                 goto nomem;
 183
 184         counter->ops = &counter_transport->ops;
 185         counter->transport = counter_transport;
 186
 187         counter->counter = counter->ops->counter_create(
 188                         number_dimensions, dimensions, 0,
 189                         -1, 0, NULL, false);
 190         if (!counter->counter) {
 191                 goto create_error;
 192         }
 193
 194         return counter;
 195
 196 create_error:
 197         free(counter);
 198 nomem:
 199 notransport:
 200         return NULL;
 201 }
 202
 203 static
 204 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 205 {
 206         counter->ops->counter_destroy(counter->counter);
 207         free(counter);
 208 }
 209
 210 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 211 {
 212         struct lttng_event_notifier_group *event_notifier_group;
 213         int i;
 214
 215         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 216         if (!event_notifier_group)
 217                 return NULL;
 218
 219         /* Add all contexts. */
 220         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 221                 free(event_notifier_group);
 222                 return NULL;
 223         }
 224
 225         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 226         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 227         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 228                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 229
 230         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 231
 232         return event_notifier_group;
 233 }
 234
 235 /*
 236  * Only used internally at session destruction.
 237  */
 238 static
 239 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 240 {
 241         struct channel *chan;
 242         struct lttng_ust_shm_handle *handle;
 243
 244         cds_list_del(&lttng_chan->node);
 245         lttng_destroy_context(lttng_chan->ctx);
 246         chan = lttng_chan->chan;
 247         handle = lttng_chan->handle;
 248         /*
 249          * note: lttng_chan is private data contained within handle. It
 250          * will be freed along with the handle.
 251          */
 252         channel_destroy(chan, handle, 0);
 253 }
 254
 255 static
 256 void register_event(struct lttng_event *event)
 257 {
 258         int ret;
 259         const struct lttng_event_desc *desc;
 260
 261         assert(event->registered == 0);
 262         desc = event->desc;
 263         ret = __tracepoint_probe_register_queue_release(desc->name,
 264                         desc->probe_callback,
 265                         event, desc->signature);
 266         WARN_ON_ONCE(ret);
 267         if (!ret)
 268                 event->registered = 1;
 269 }
 270
 271 static
 272 void register_event_notifier(struct lttng_event_notifier *event_notifier)
 273 {
 274         int ret;
 275         const struct lttng_event_desc *desc;
 276
 277         assert(event_notifier->registered == 0);
 278         desc = event_notifier->desc;
 279         ret = __tracepoint_probe_register_queue_release(desc->name,
 280                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 281         WARN_ON_ONCE(ret);
 282         if (!ret)
 283                 event_notifier->registered = 1;
 284 }
 285
 286 static
 287 void unregister_event(struct lttng_event *event)
 288 {
 289         int ret;
 290         const struct lttng_event_desc *desc;
 291
 292         assert(event->registered == 1);
 293         desc = event->desc;
 294         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 295                         desc->probe_callback,
 296                         event);
 297         WARN_ON_ONCE(ret);
 298         if (!ret)
 299                 event->registered = 0;
 300 }
 301
 302 static
 303 void unregister_event_notifier(struct lttng_event_notifier *event_notifier)
 304 {
 305         int ret;
 306         const struct lttng_event_desc *desc;
 307
 308         assert(event_notifier->registered == 1);
 309         desc = event_notifier->desc;
 310         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 311                 desc->u.ext.event_notifier_callback, event_notifier);
 312         WARN_ON_ONCE(ret);
 313         if (!ret)
 314                 event_notifier->registered = 0;
 315 }
 316
 317 /*
 318  * Only used internally at session destruction.
 319  */
 320 static
 321 void _lttng_event_unregister(struct lttng_event *event)
 322 {
 323         if (event->registered)
 324                 unregister_event(event);
 325 }
 326
 327 /*
 328  * Only used internally at session destruction.
 329  */
 330 static
 331 void _lttng_event_notifier_unregister(struct lttng_event_notifier *event_notifier)
 332 {
 333         if (event_notifier->registered)
 334                 unregister_event_notifier(event_notifier);
 335 }
 336
 337 void lttng_session_destroy(struct lttng_session *session)
 338 {
 339         struct lttng_channel *chan, *tmpchan;
 340         struct lttng_event *event, *tmpevent;
 341         struct lttng_enum *_enum, *tmp_enum;
 342         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 343
 344         CMM_ACCESS_ONCE(session->active) = 0;
 345         cds_list_for_each_entry(event, &session->events_head, node) {
 346                 _lttng_event_unregister(event);
 347         }
 348         lttng_ust_synchronize_trace();  /* Wait for in-flight events to complete */
 349         __tracepoint_probe_prune_release_queue();
 350         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 351                         &session->enablers_head, node)
 352                 lttng_event_enabler_destroy(event_enabler);
 353         cds_list_for_each_entry_safe(event, tmpevent,
 354                         &session->events_head, node)
 355                 _lttng_event_destroy(event);
 356         cds_list_for_each_entry_safe(_enum, tmp_enum,
 357                         &session->enums_head, node)
 358                 _lttng_enum_destroy(_enum);
 359         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 360                 _lttng_channel_unmap(chan);
 361         cds_list_del(&session->node);
 362         lttng_destroy_context(session->ctx);
 363         free(session);
 364 }
 365
 366 void lttng_event_notifier_group_destroy(
 367                 struct lttng_event_notifier_group *event_notifier_group)
 368 {
 369         int close_ret;
 370         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 371         struct lttng_event_notifier *notifier, *tmpnotifier;
 372
 373         if (!event_notifier_group) {
 374                 return;
 375         }
 376
 377         cds_list_for_each_entry(notifier,
 378                         &event_notifier_group->event_notifiers_head, node)
 379                 _lttng_event_notifier_unregister(notifier);
 380
 381         lttng_ust_synchronize_trace();
 382
 383         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 384                         &event_notifier_group->enablers_head, node)
 385                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 386
 387         cds_list_for_each_entry_safe(notifier, tmpnotifier,
 388                         &event_notifier_group->event_notifiers_head, node)
 389                 _lttng_event_notifier_destroy(notifier);
 390
 391         if (event_notifier_group->error_counter)
 392                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 393
 394         /* Close the notification fd to the listener of event_notifiers. */
 395
 396         lttng_ust_lock_fd_tracker();
 397         close_ret = close(event_notifier_group->notification_fd);
 398         if (!close_ret) {
 399                 lttng_ust_delete_fd_from_tracker(
 400                                 event_notifier_group->notification_fd);
 401         } else {
 402                 PERROR("close");
 403                 abort();
 404         }
 405         lttng_ust_unlock_fd_tracker();
 406
 407         cds_list_del(&event_notifier_group->node);
 408
 409         free(event_notifier_group);
 410 }
 411
 412 static
 413 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 414 {
 415         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 416         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 417
 418         if (!enabler) {
 419                 return;
 420         }
 421
 422         /* Destroy filter bytecode */
 423         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 424                         &enabler->filter_bytecode_head, node) {
 425                 free(filter_node);
 426         }
 427
 428         /* Destroy excluders */
 429         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 430                         &enabler->excluder_head, node) {
 431                 free(excluder_node);
 432         }
 433 }
 434
 435  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 436 {
 437         if (!event_notifier_enabler) {
 438                 return;
 439         }
 440
 441         cds_list_del(&event_notifier_enabler->node);
 442
 443         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 444
 445         free(event_notifier_enabler);
 446 }
 447
 448 static
 449 int lttng_enum_create(const struct lttng_enum_desc *desc,
 450                 struct lttng_session *session)
 451 {
 452         const char *enum_name = desc->name;
 453         struct lttng_enum *_enum;
 454         struct cds_hlist_head *head;
 455         int ret = 0;
 456         size_t name_len = strlen(enum_name);
 457         uint32_t hash;
 458         int notify_socket;
 459
 460         /* Check if this enum is already registered for this session. */
 461         hash = jhash(enum_name, name_len, 0);
 462         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 463
 464         _enum = lttng_ust_enum_get_from_desc(session, desc);
 465         if (_enum) {
 466                 ret = -EEXIST;
 467                 goto exist;
 468         }
 469
 470         notify_socket = lttng_get_notify_socket(session->owner);
 471         if (notify_socket < 0) {
 472                 ret = notify_socket;
 473                 goto socket_error;
 474         }
 475
 476         _enum = zmalloc(sizeof(*_enum));
 477         if (!_enum) {
 478                 ret = -ENOMEM;
 479                 goto cache_error;
 480         }
 481         _enum->session = session;
 482         _enum->desc = desc;
 483
 484         ret = ustcomm_register_enum(notify_socket,
 485                 session->objd,
 486                 enum_name,
 487                 desc->nr_entries,
 488                 desc->entries,
 489                 &_enum->id);
 490         if (ret < 0) {
 491                 DBG("Error (%d) registering enumeration to sessiond", ret);
 492                 goto sessiond_register_error;
 493         }
 494         cds_list_add(&_enum->node, &session->enums_head);
 495         cds_hlist_add_head(&_enum->hlist, head);
 496         return 0;
 497
 498 sessiond_register_error:
 499         free(_enum);
 500 cache_error:
 501 socket_error:
 502 exist:
 503         return ret;
 504 }
 505
 506 static
 507 int lttng_create_enum_check(const struct lttng_type *type,
 508                 struct lttng_session *session)
 509 {
 510         switch (type->atype) {
 511         case atype_enum:
 512         {
 513                 const struct lttng_enum_desc *enum_desc;
 514                 int ret;
 515
 516                 enum_desc = type->u.legacy.basic.enumeration.desc;
 517                 ret = lttng_enum_create(enum_desc, session);
 518                 if (ret && ret != -EEXIST) {
 519                         DBG("Unable to create enum error: (%d)", ret);
 520                         return ret;
 521                 }
 522                 break;
 523         }
 524         case atype_enum_nestable:
 525         {
 526                 const struct lttng_enum_desc *enum_desc;
 527                 int ret;
 528
 529                 enum_desc = type->u.enum_nestable.desc;
 530                 ret = lttng_enum_create(enum_desc, session);
 531                 if (ret && ret != -EEXIST) {
 532                         DBG("Unable to create enum error: (%d)", ret);
 533                         return ret;
 534                 }
 535                 break;
 536         }
 537         case atype_dynamic:
 538         {
 539                 const struct lttng_event_field *tag_field_generic;
 540                 const struct lttng_enum_desc *enum_desc;
 541                 int ret;
 542
 543                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 544                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 545                 ret = lttng_enum_create(enum_desc, session);
 546                 if (ret && ret != -EEXIST) {
 547                         DBG("Unable to create enum error: (%d)", ret);
 548                         return ret;
 549                 }
 550                 break;
 551         }
 552         default:
 553                 /* TODO: nested types when they become supported. */
 554                 break;
 555         }
 556         return 0;
 557 }
 558
 559 static
 560 int lttng_create_all_event_enums(size_t nr_fields,
 561                 const struct lttng_event_field *event_fields,
 562                 struct lttng_session *session)
 563 {
 564         size_t i;
 565         int ret;
 566
 567         /* For each field, ensure enum is part of the session. */
 568         for (i = 0; i < nr_fields; i++) {
 569                 const struct lttng_type *type = &event_fields[i].type;
 570
 571                 ret = lttng_create_enum_check(type, session);
 572                 if (ret)
 573                         return ret;
 574         }
 575         return 0;
 576 }
 577
 578 static
 579 int lttng_create_all_ctx_enums(size_t nr_fields,
 580                 const struct lttng_ctx_field *ctx_fields,
 581                 struct lttng_session *session)
 582 {
 583         size_t i;
 584         int ret;
 585
 586         /* For each field, ensure enum is part of the session. */
 587         for (i = 0; i < nr_fields; i++) {
 588                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 589
 590                 ret = lttng_create_enum_check(type, session);
 591                 if (ret)
 592                         return ret;
 593         }
 594         return 0;
 595 }
 596
 597 /*
 598  * Ensure that a state-dump will be performed for this session at the end
 599  * of the current handle_message().
 600  */
 601 int lttng_session_statedump(struct lttng_session *session)
 602 {
 603         session->statedump_pending = 1;
 604         lttng_ust_sockinfo_session_enabled(session->owner);
 605         return 0;
 606 }
 607
 608 int lttng_session_enable(struct lttng_session *session)
 609 {
 610         int ret = 0;
 611         struct lttng_channel *chan;
 612         int notify_socket;
 613
 614         if (session->active) {
 615                 ret = -EBUSY;
 616                 goto end;
 617         }
 618
 619         notify_socket = lttng_get_notify_socket(session->owner);
 620         if (notify_socket < 0)
 621                 return notify_socket;
 622
 623         /* Set transient enabler state to "enabled" */
 624         session->tstate = 1;
 625
 626         /* We need to sync enablers with session before activation. */
 627         lttng_session_sync_event_enablers(session);
 628
 629         /*
 630          * Snapshot the number of events per channel to know the type of header
 631          * we need to use.
 632          */
 633         cds_list_for_each_entry(chan, &session->chan_head, node) {
 634                 const struct lttng_ctx *ctx;
 635                 const struct lttng_ctx_field *fields = NULL;
 636                 size_t nr_fields = 0;
 637                 uint32_t chan_id;
 638
 639                 /* don't change it if session stop/restart */
 640                 if (chan->header_type)
 641                         continue;
 642                 ctx = chan->ctx;
 643                 if (ctx) {
 644                         nr_fields = ctx->nr_fields;
 645                         fields = ctx->fields;
 646                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 647                                 session);
 648                         if (ret < 0) {
 649                                 DBG("Error (%d) adding enum to session", ret);
 650                                 return ret;
 651                         }
 652                 }
 653                 ret = ustcomm_register_channel(notify_socket,
 654                         session,
 655                         session->objd,
 656                         chan->objd,
 657                         nr_fields,
 658                         fields,
 659                         &chan_id,
 660                         &chan->header_type);
 661                 if (ret) {
 662                         DBG("Error (%d) registering channel to sessiond", ret);
 663                         return ret;
 664                 }
 665                 if (chan_id != chan->id) {
 666                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 667                                 chan_id, chan->id);
 668                         return -EINVAL;
 669                 }
 670         }
 671
 672         /* Set atomically the state to "active" */
 673         CMM_ACCESS_ONCE(session->active) = 1;
 674         CMM_ACCESS_ONCE(session->been_active) = 1;
 675
 676         ret = lttng_session_statedump(session);
 677         if (ret)
 678                 return ret;
 679 end:
 680         return ret;
 681 }
 682
 683 int lttng_session_disable(struct lttng_session *session)
 684 {
 685         int ret = 0;
 686
 687         if (!session->active) {
 688                 ret = -EBUSY;
 689                 goto end;
 690         }
 691         /* Set atomically the state to "inactive" */
 692         CMM_ACCESS_ONCE(session->active) = 0;
 693
 694         /* Set transient enabler state to "disabled" */
 695         session->tstate = 0;
 696         lttng_session_sync_event_enablers(session);
 697 end:
 698         return ret;
 699 }
 700
 701 int lttng_channel_enable(struct lttng_channel *channel)
 702 {
 703         int ret = 0;
 704
 705         if (channel->enabled) {
 706                 ret = -EBUSY;
 707                 goto end;
 708         }
 709         /* Set transient enabler state to "enabled" */
 710         channel->tstate = 1;
 711         lttng_session_sync_event_enablers(channel->session);
 712         /* Set atomically the state to "enabled" */
 713         CMM_ACCESS_ONCE(channel->enabled) = 1;
 714 end:
 715         return ret;
 716 }
 717
 718 int lttng_channel_disable(struct lttng_channel *channel)
 719 {
 720         int ret = 0;
 721
 722         if (!channel->enabled) {
 723                 ret = -EBUSY;
 724                 goto end;
 725         }
 726         /* Set atomically the state to "disabled" */
 727         CMM_ACCESS_ONCE(channel->enabled) = 0;
 728         /* Set transient enabler state to "enabled" */
 729         channel->tstate = 0;
 730         lttng_session_sync_event_enablers(channel->session);
 731 end:
 732         return ret;
 733 }
 734
 735 static inline
 736 struct cds_hlist_head *borrow_hash_table_bucket(
 737                 struct cds_hlist_head *hash_table,
 738                 unsigned int hash_table_size,
 739                 const struct lttng_event_desc *desc)
 740 {
 741         const char *event_name;
 742         size_t name_len;
 743         uint32_t hash;
 744
 745         event_name = desc->name;
 746         name_len = strlen(event_name);
 747
 748         hash = jhash(event_name, name_len, 0);
 749         return &hash_table[hash & (hash_table_size - 1)];
 750 }
 751
 752 /*
 753  * Supports event creation while tracing session is active.
 754  */
 755 static
 756 int lttng_event_create(const struct lttng_event_desc *desc,
 757                 struct lttng_channel *chan)
 758 {
 759         struct lttng_event *event;
 760         struct lttng_session *session = chan->session;
 761         struct cds_hlist_head *head;
 762         int ret = 0;
 763         int notify_socket, loglevel;
 764         const char *uri;
 765
 766         head = borrow_hash_table_bucket(chan->session->events_ht.table,
 767                 LTTNG_UST_EVENT_HT_SIZE, desc);
 768
 769         notify_socket = lttng_get_notify_socket(session->owner);
 770         if (notify_socket < 0) {
 771                 ret = notify_socket;
 772                 goto socket_error;
 773         }
 774
 775         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 776                         session);
 777         if (ret < 0) {
 778                 DBG("Error (%d) adding enum to session", ret);
 779                 goto create_enum_error;
 780         }
 781
 782         /*
 783          * Check if loglevel match. Refuse to connect event if not.
 784          */
 785         event = zmalloc(sizeof(struct lttng_event));
 786         if (!event) {
 787                 ret = -ENOMEM;
 788                 goto cache_error;
 789         }
 790         event->chan = chan;
 791
 792         /* Event will be enabled by enabler sync. */
 793         event->enabled = 0;
 794         event->registered = 0;
 795         CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
 796         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 797         event->desc = desc;
 798
 799         if (desc->loglevel)
 800                 loglevel = *(*event->desc->loglevel);
 801         else
 802                 loglevel = TRACE_DEFAULT;
 803         if (desc->u.ext.model_emf_uri)
 804                 uri = *(desc->u.ext.model_emf_uri);
 805         else
 806                 uri = NULL;
 807
 808         /* Fetch event ID from sessiond */
 809         ret = ustcomm_register_event(notify_socket,
 810                 session,
 811                 session->objd,
 812                 chan->objd,
 813                 desc->name,
 814                 loglevel,
 815                 desc->signature,
 816                 desc->nr_fields,
 817                 desc->fields,
 818                 uri,
 819                 &event->id);
 820         if (ret < 0) {
 821                 DBG("Error (%d) registering event to sessiond", ret);
 822                 goto sessiond_register_error;
 823         }
 824
 825         cds_list_add(&event->node, &chan->session->events_head);
 826         cds_hlist_add_head(&event->hlist, head);
 827         return 0;
 828
 829 sessiond_register_error:
 830         free(event);
 831 cache_error:
 832 create_enum_error:
 833 socket_error:
 834         return ret;
 835 }
 836
 837 static
 838 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 839                 uint64_t token, uint64_t error_counter_index,
 840                 struct lttng_event_notifier_group *event_notifier_group)
 841 {
 842         struct lttng_event_notifier *event_notifier;
 843         struct cds_hlist_head *head;
 844         int ret = 0;
 845
 846         /*
 847          * Get the hashtable bucket the created lttng_event_notifier object
 848          * should be inserted.
 849          */
 850         head = borrow_hash_table_bucket(
 851                 event_notifier_group->event_notifiers_ht.table,
 852                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 853
 854         event_notifier = zmalloc(sizeof(struct lttng_event_notifier));
 855         if (!event_notifier) {
 856                 ret = -ENOMEM;
 857                 goto error;
 858         }
 859
 860         event_notifier->group = event_notifier_group;
 861         event_notifier->user_token = token;
 862         event_notifier->error_counter_index = error_counter_index;
 863
 864         /* Event notifier will be enabled by enabler sync. */
 865         event_notifier->enabled = 0;
 866         event_notifier->registered = 0;
 867
 868         CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
 869         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 870         CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
 871         event_notifier->desc = desc;
 872         event_notifier->notification_send = lttng_event_notifier_notification_send;
 873
 874         cds_list_add(&event_notifier->node,
 875                         &event_notifier_group->event_notifiers_head);
 876         cds_hlist_add_head(&event_notifier->hlist, head);
 877
 878         return 0;
 879
 880 error:
 881         return ret;
 882 }
 883
 884 static
 885 void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
 886 {
 887         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 888
 889         /* Remove from event_notifier list. */
 890         cds_list_del(&event_notifier->node);
 891         /* Remove from event_notifier hash table. */
 892         cds_hlist_del(&event_notifier->hlist);
 893
 894         lttng_free_event_notifier_filter_runtime(event_notifier);
 895
 896         /* Free event_notifier enabler refs */
 897         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 898                         &event_notifier->enablers_ref_head, node)
 899                 free(enabler_ref);
 900         free(event_notifier);
 901 }
 902
 903 static
 904 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 905                 struct lttng_enabler *enabler)
 906 {
 907         int loglevel = 0;
 908         unsigned int has_loglevel = 0;
 909
 910         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 911         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 912                         desc->name, SIZE_MAX))
 913                 return 0;
 914         if (desc->loglevel) {
 915                 loglevel = *(*desc->loglevel);
 916                 has_loglevel = 1;
 917         }
 918         if (!lttng_loglevel_match(loglevel,
 919                         has_loglevel,
 920                         enabler->event_param.loglevel_type,
 921                         enabler->event_param.loglevel))
 922                 return 0;
 923         return 1;
 924 }
 925
 926 static
 927 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 928                 struct lttng_enabler *enabler)
 929 {
 930         int loglevel = 0;
 931         unsigned int has_loglevel = 0;
 932
 933         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 934         if (strcmp(desc->name, enabler->event_param.name))
 935                 return 0;
 936         if (desc->loglevel) {
 937                 loglevel = *(*desc->loglevel);
 938                 has_loglevel = 1;
 939         }
 940         if (!lttng_loglevel_match(loglevel,
 941                         has_loglevel,
 942                         enabler->event_param.loglevel_type,
 943                         enabler->event_param.loglevel))
 944                 return 0;
 945         return 1;
 946 }
 947
 948 static
 949 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 950                 struct lttng_enabler *enabler)
 951 {
 952         switch (enabler->format_type) {
 953         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 954         {
 955                 struct lttng_ust_excluder_node *excluder;
 956
 957                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 958                         return 0;
 959                 }
 960
 961                 /*
 962                  * If the matching event matches with an excluder,
 963                  * return 'does not match'
 964                  */
 965                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 966                         int count;
 967
 968                         for (count = 0; count < excluder->excluder.count; count++) {
 969                                 int len;
 970                                 char *excluder_name;
 971
 972                                 excluder_name = (char *) (excluder->excluder.names)
 973                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 974                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 975                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 976                                         return 0;
 977                         }
 978                 }
 979                 return 1;
 980         }
 981         case LTTNG_ENABLER_FORMAT_EVENT:
 982                 return lttng_desc_match_event_enabler(desc, enabler);
 983         default:
 984                 return -EINVAL;
 985         }
 986 }
 987
 988 static
 989 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 990                 struct lttng_event *event)
 991 {
 992         if (lttng_desc_match_enabler(event->desc,
 993                         lttng_event_enabler_as_enabler(event_enabler))
 994                         && event->chan == event_enabler->chan)
 995                 return 1;
 996         else
 997                 return 0;
 998 }
 999
1000 static
1001 int lttng_event_notifier_enabler_match_event_notifier(
1002                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1003                 struct lttng_event_notifier *event_notifier)
1004 {
1005         int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
1006                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1007
1008         if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
1009                         event_notifier->user_token == event_notifier_enabler->user_token)
1010                 return 1;
1011         else
1012                 return 0;
1013 }
1014
1015 static
1016 struct lttng_enabler_ref *lttng_enabler_ref(
1017                 struct cds_list_head *enabler_ref_list,
1018                 struct lttng_enabler *enabler)
1019 {
1020         struct lttng_enabler_ref *enabler_ref;
1021
1022         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1023                 if (enabler_ref->ref == enabler)
1024                         return enabler_ref;
1025         }
1026         return NULL;
1027 }
1028
1029 /*
1030  * Create struct lttng_event if it is missing and present in the list of
1031  * tracepoint probes.
1032  */
1033 static
1034 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1035 {
1036         struct lttng_session *session = event_enabler->chan->session;
1037         struct lttng_probe_desc *probe_desc;
1038         const struct lttng_event_desc *desc;
1039         struct lttng_event *event;
1040         int i;
1041         struct cds_list_head *probe_list;
1042
1043         probe_list = lttng_get_probe_list_head();
1044         /*
1045          * For each probe event, if we find that a probe event matches
1046          * our enabler, create an associated lttng_event if not
1047          * already present.
1048          */
1049         cds_list_for_each_entry(probe_desc, probe_list, head) {
1050                 for (i = 0; i < probe_desc->nr_events; i++) {
1051                         int ret;
1052                         bool found = false;
1053                         struct cds_hlist_head *head;
1054                         struct cds_hlist_node *node;
1055
1056                         desc = probe_desc->event_desc[i];
1057                         if (!lttng_desc_match_enabler(desc,
1058                                         lttng_event_enabler_as_enabler(event_enabler)))
1059                                 continue;
1060
1061                         head = borrow_hash_table_bucket(
1062                                 session->events_ht.table,
1063                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1064
1065                         cds_hlist_for_each_entry(event, node, head, hlist) {
1066                                 if (event->desc == desc
1067                                                 && event->chan == event_enabler->chan) {
1068                                         found = true;
1069                                         break;
1070                                 }
1071                         }
1072                         if (found)
1073                                 continue;
1074
1075                         /*
1076                          * We need to create an event for this
1077                          * event probe.
1078                          */
1079                         ret = lttng_event_create(probe_desc->event_desc[i],
1080                                         event_enabler->chan);
1081                         if (ret) {
1082                                 DBG("Unable to create event %s, error %d\n",
1083                                         probe_desc->event_desc[i]->name, ret);
1084                         }
1085                 }
1086         }
1087 }
1088
1089 static
1090 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1091                 void (*event_func)(struct lttng_session *session,
1092                         struct lttng_event *event),
1093                 void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
1094 {
1095         struct cds_hlist_node *node, *tmp_node;
1096         struct cds_list_head *sessionsp;
1097         unsigned int i;
1098
1099         /* Get handle on list of sessions. */
1100         sessionsp = _lttng_get_sessions();
1101
1102         /*
1103          * Iterate over all events in the probe provider descriptions and
1104          * sessions to queue the unregistration of the events.
1105          */
1106         for (i = 0; i < provider_desc->nr_events; i++) {
1107                 const struct lttng_event_desc *event_desc;
1108                 struct lttng_event_notifier_group *event_notifier_group;
1109                 struct lttng_event_notifier *event_notifier;
1110                 struct lttng_session *session;
1111                 struct cds_hlist_head *head;
1112                 struct lttng_event *event;
1113
1114                 event_desc = provider_desc->event_desc[i];
1115
1116                 /*
1117                  * Iterate over all session to find the current event
1118                  * description.
1119                  */
1120                 cds_list_for_each_entry(session, sessionsp, node) {
1121                         /*
1122                          * Get the list of events in the hashtable bucket and
1123                          * iterate to find the event matching this descriptor.
1124                          */
1125                         head = borrow_hash_table_bucket(
1126                                 session->events_ht.table,
1127                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1128
1129                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1130                                 if (event_desc == event->desc) {
1131                                         event_func(session, event);
1132                                         break;
1133                                 }
1134                         }
1135                 }
1136
1137                 /*
1138                  * Iterate over all event_notifier groups to find the current event
1139                  * description.
1140                  */
1141                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1142                         /*
1143                          * Get the list of event_notifiers in the hashtable bucket and
1144                          * iterate to find the event_notifier matching this
1145                          * descriptor.
1146                          */
1147                         head = borrow_hash_table_bucket(
1148                                 event_notifier_group->event_notifiers_ht.table,
1149                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1150
1151                         cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
1152                                 if (event_desc == event_notifier->desc) {
1153                                         event_notifier_func(event_notifier);
1154                                         break;
1155                                 }
1156                         }
1157                 }
1158         }
1159 }
1160
1161 static
1162 void _unregister_event(struct lttng_session *session,
1163                 struct lttng_event *event)
1164 {
1165         _lttng_event_unregister(event);
1166 }
1167
1168 static
1169 void _event_enum_destroy(struct lttng_session *session,
1170                 struct lttng_event *event)
1171 {
1172         unsigned int i;
1173
1174         /* Destroy enums of the current event. */
1175         for (i = 0; i < event->desc->nr_fields; i++) {
1176                 const struct lttng_enum_desc *enum_desc;
1177                 const struct lttng_event_field *field;
1178                 struct lttng_enum *curr_enum;
1179
1180                 field = &(event->desc->fields[i]);
1181                 switch (field->type.atype) {
1182                 case atype_enum:
1183                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1184                         break;
1185                 case atype_enum_nestable:
1186                         enum_desc = field->type.u.enum_nestable.desc;
1187                         break;
1188                 default:
1189                         continue;
1190                 }
1191
1192                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1193                 if (curr_enum) {
1194                         _lttng_enum_destroy(curr_enum);
1195                 }
1196         }
1197
1198         /* Destroy event. */
1199         _lttng_event_destroy(event);
1200 }
1201
1202 /*
1203  * Iterate over all the UST sessions to unregister and destroy all probes from
1204  * the probe provider descriptor received as argument. Must me called with the
1205  * ust_lock held.
1206  */
1207 void lttng_probe_provider_unregister_events(
1208                 struct lttng_probe_desc *provider_desc)
1209 {
1210         /*
1211          * Iterate over all events in the probe provider descriptions and sessions
1212          * to queue the unregistration of the events.
1213          */
1214         probe_provider_event_for_each(provider_desc, _unregister_event,
1215                 _lttng_event_notifier_unregister);
1216
1217         /* Wait for grace period. */
1218         lttng_ust_synchronize_trace();
1219         /* Prune the unregistration queue. */
1220         __tracepoint_probe_prune_release_queue();
1221
1222         /*
1223          * It is now safe to destroy the events and remove them from the event list
1224          * and hashtables.
1225          */
1226         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1227                 _lttng_event_notifier_destroy);
1228 }
1229
1230 /*
1231  * Create events associated with an event enabler (if not already present),
1232  * and add backward reference from the event to the enabler.
1233  */
1234 static
1235 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1236 {
1237         struct lttng_session *session = event_enabler->chan->session;
1238         struct lttng_event *event;
1239
1240         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1241                 goto end;
1242
1243         /* First ensure that probe events are created for this enabler. */
1244         lttng_create_event_if_missing(event_enabler);
1245
1246         /* For each event matching enabler in session event list. */
1247         cds_list_for_each_entry(event, &session->events_head, node) {
1248                 struct lttng_enabler_ref *enabler_ref;
1249
1250                 if (!lttng_event_enabler_match_event(event_enabler, event))
1251                         continue;
1252
1253                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1254                         lttng_event_enabler_as_enabler(event_enabler));
1255                 if (!enabler_ref) {
1256                         /*
1257                          * If no backward ref, create it.
1258                          * Add backward ref from event to enabler.
1259                          */
1260                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1261                         if (!enabler_ref)
1262                                 return -ENOMEM;
1263                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1264                                 event_enabler);
1265                         cds_list_add(&enabler_ref->node,
1266                                 &event->enablers_ref_head);
1267                 }
1268
1269                 /*
1270                  * Link filter bytecodes if not linked yet.
1271                  */
1272                 lttng_enabler_link_bytecode(event->desc,
1273                         &session->ctx,
1274                         &event->filter_bytecode_runtime_head,
1275                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1276
1277                 /* TODO: merge event context. */
1278         }
1279 end:
1280         return 0;
1281 }
1282
1283 /*
1284  * Called at library load: connect the probe on all enablers matching
1285  * this event.
1286  * Called with session mutex held.
1287  */
1288 int lttng_fix_pending_events(void)
1289 {
1290         struct lttng_session *session;
1291
1292         cds_list_for_each_entry(session, &sessions, node) {
1293                 lttng_session_lazy_sync_event_enablers(session);
1294         }
1295         return 0;
1296 }
1297
1298 int lttng_fix_pending_event_notifiers(void)
1299 {
1300         struct lttng_event_notifier_group *event_notifier_group;
1301
1302         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1303                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1304         }
1305         return 0;
1306 }
1307
1308 /*
1309  * For each session of the owner thread, execute pending statedump.
1310  * Only dump state for the sessions owned by the caller thread, because
1311  * we don't keep ust_lock across the entire iteration.
1312  */
1313 void lttng_handle_pending_statedump(void *owner)
1314 {
1315         struct lttng_session *session;
1316
1317         /* Execute state dump */
1318         do_lttng_ust_statedump(owner);
1319
1320         /* Clear pending state dump */
1321         if (ust_lock()) {
1322                 goto end;
1323         }
1324         cds_list_for_each_entry(session, &sessions, node) {
1325                 if (session->owner != owner)
1326                         continue;
1327                 if (!session->statedump_pending)
1328                         continue;
1329                 session->statedump_pending = 0;
1330         }
1331 end:
1332         ust_unlock();
1333         return;
1334 }
1335
1336 /*
1337  * Only used internally at session destruction.
1338  */
1339 static
1340 void _lttng_event_destroy(struct lttng_event *event)
1341 {
1342         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1343
1344         /* Remove from event list. */
1345         cds_list_del(&event->node);
1346         /* Remove from event hash table. */
1347         cds_hlist_del(&event->hlist);
1348
1349         lttng_destroy_context(event->ctx);
1350         lttng_free_event_filter_runtime(event);
1351         /* Free event enabler refs */
1352         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1353                         &event->enablers_ref_head, node)
1354                 free(enabler_ref);
1355         free(event);
1356 }
1357
1358 static
1359 void _lttng_enum_destroy(struct lttng_enum *_enum)
1360 {
1361         cds_list_del(&_enum->node);
1362         cds_hlist_del(&_enum->hlist);
1363         free(_enum);
1364 }
1365
1366 void lttng_ust_events_exit(void)
1367 {
1368         struct lttng_session *session, *tmpsession;
1369
1370         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1371                 lttng_session_destroy(session);
1372 }
1373
1374 /*
1375  * Enabler management.
1376  */
1377 struct lttng_event_enabler *lttng_event_enabler_create(
1378                 enum lttng_enabler_format_type format_type,
1379                 struct lttng_ust_event *event_param,
1380                 struct lttng_channel *chan)
1381 {
1382         struct lttng_event_enabler *event_enabler;
1383
1384         event_enabler = zmalloc(sizeof(*event_enabler));
1385         if (!event_enabler)
1386                 return NULL;
1387         event_enabler->base.format_type = format_type;
1388         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1389         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1390         memcpy(&event_enabler->base.event_param, event_param,
1391                 sizeof(event_enabler->base.event_param));
1392         event_enabler->chan = chan;
1393         /* ctx left NULL */
1394         event_enabler->base.enabled = 0;
1395         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1396         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1397
1398         return event_enabler;
1399 }
1400
1401 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1402                 struct lttng_event_notifier_group *event_notifier_group,
1403                 enum lttng_enabler_format_type format_type,
1404                 struct lttng_ust_event_notifier *event_notifier_param)
1405 {
1406         struct lttng_event_notifier_enabler *event_notifier_enabler;
1407
1408         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1409         if (!event_notifier_enabler)
1410                 return NULL;
1411         event_notifier_enabler->base.format_type = format_type;
1412         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1413         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1414         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1415
1416         event_notifier_enabler->user_token = event_notifier_param->event.token;
1417         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1418         event_notifier_enabler->num_captures = 0;
1419
1420         memcpy(&event_notifier_enabler->base.event_param.name,
1421                 event_notifier_param->event.name,
1422                 sizeof(event_notifier_enabler->base.event_param.name));
1423         event_notifier_enabler->base.event_param.instrumentation =
1424                 event_notifier_param->event.instrumentation;
1425         event_notifier_enabler->base.event_param.loglevel =
1426                 event_notifier_param->event.loglevel;
1427         event_notifier_enabler->base.event_param.loglevel_type =
1428                 event_notifier_param->event.loglevel_type;
1429
1430         event_notifier_enabler->base.enabled = 0;
1431         event_notifier_enabler->group = event_notifier_group;
1432
1433         cds_list_add(&event_notifier_enabler->node,
1434                         &event_notifier_group->enablers_head);
1435
1436         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1437
1438         return event_notifier_enabler;
1439 }
1440
1441 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1442 {
1443         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1444         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1445
1446         return 0;
1447 }
1448
1449 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1450 {
1451         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1452         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1453
1454         return 0;
1455 }
1456
1457 static
1458 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1459                 struct lttng_ust_bytecode_node **bytecode)
1460 {
1461         (*bytecode)->enabler = enabler;
1462         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1463         /* Take ownership of bytecode */
1464         *bytecode = NULL;
1465 }
1466
1467 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1468                 struct lttng_ust_bytecode_node **bytecode)
1469 {
1470         _lttng_enabler_attach_filter_bytecode(
1471                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1472
1473         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1474         return 0;
1475 }
1476
1477 static
1478 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1479                 struct lttng_ust_excluder_node **excluder)
1480 {
1481         (*excluder)->enabler = enabler;
1482         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1483         /* Take ownership of excluder */
1484         *excluder = NULL;
1485 }
1486
1487 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1488                 struct lttng_ust_excluder_node **excluder)
1489 {
1490         _lttng_enabler_attach_exclusion(
1491                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1492
1493         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1494         return 0;
1495 }
1496
1497 int lttng_event_notifier_enabler_enable(
1498                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1499 {
1500         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1501         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1502
1503         return 0;
1504 }
1505
1506 int lttng_event_notifier_enabler_disable(
1507                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1508 {
1509         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1510         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1511
1512         return 0;
1513 }
1514
1515 int lttng_event_notifier_enabler_attach_filter_bytecode(
1516                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1517                 struct lttng_ust_bytecode_node **bytecode)
1518 {
1519         _lttng_enabler_attach_filter_bytecode(
1520                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1521                 bytecode);
1522
1523         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1524         return 0;
1525 }
1526
1527 int lttng_event_notifier_enabler_attach_capture_bytecode(
1528                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1529                 struct lttng_ust_bytecode_node **bytecode)
1530 {
1531         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1532                         event_notifier_enabler);
1533         cds_list_add_tail(&(*bytecode)->node,
1534                         &event_notifier_enabler->capture_bytecode_head);
1535         /* Take ownership of bytecode */
1536         *bytecode = NULL;
1537         event_notifier_enabler->num_captures++;
1538
1539         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1540         return 0;
1541 }
1542
1543 int lttng_event_notifier_enabler_attach_exclusion(
1544                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1545                 struct lttng_ust_excluder_node **excluder)
1546 {
1547         _lttng_enabler_attach_exclusion(
1548                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1549                 excluder);
1550
1551         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1552         return 0;
1553 }
1554
1555 int lttng_attach_context(struct lttng_ust_context *context_param,
1556                 union ust_args *uargs,
1557                 struct lttng_ctx **ctx, struct lttng_session *session)
1558 {
1559         /*
1560          * We cannot attach a context after trace has been started for a
1561          * session because the metadata does not allow expressing this
1562          * information outside of the original channel scope.
1563          */
1564         if (session->been_active)
1565                 return -EPERM;
1566
1567         switch (context_param->ctx) {
1568         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1569                 return lttng_add_pthread_id_to_ctx(ctx);
1570         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1571         {
1572                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1573
1574                 perf_ctx_param = &context_param->u.perf_counter;
1575                 return lttng_add_perf_counter_to_ctx(
1576                         perf_ctx_param->type,
1577                         perf_ctx_param->config,
1578                         perf_ctx_param->name,
1579                         ctx);
1580         }
1581         case LTTNG_UST_CONTEXT_VTID:
1582                 return lttng_add_vtid_to_ctx(ctx);
1583         case LTTNG_UST_CONTEXT_VPID:
1584                 return lttng_add_vpid_to_ctx(ctx);
1585         case LTTNG_UST_CONTEXT_PROCNAME:
1586                 return lttng_add_procname_to_ctx(ctx);
1587         case LTTNG_UST_CONTEXT_IP:
1588                 return lttng_add_ip_to_ctx(ctx);
1589         case LTTNG_UST_CONTEXT_CPU_ID:
1590                 return lttng_add_cpu_id_to_ctx(ctx);
1591         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1592                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1593                         ctx);
1594         case LTTNG_UST_CONTEXT_CGROUP_NS:
1595                 return lttng_add_cgroup_ns_to_ctx(ctx);
1596         case LTTNG_UST_CONTEXT_IPC_NS:
1597                 return lttng_add_ipc_ns_to_ctx(ctx);
1598         case LTTNG_UST_CONTEXT_MNT_NS:
1599                 return lttng_add_mnt_ns_to_ctx(ctx);
1600         case LTTNG_UST_CONTEXT_NET_NS:
1601                 return lttng_add_net_ns_to_ctx(ctx);
1602         case LTTNG_UST_CONTEXT_PID_NS:
1603                 return lttng_add_pid_ns_to_ctx(ctx);
1604         case LTTNG_UST_CONTEXT_TIME_NS:
1605                 return lttng_add_time_ns_to_ctx(ctx);
1606         case LTTNG_UST_CONTEXT_USER_NS:
1607                 return lttng_add_user_ns_to_ctx(ctx);
1608         case LTTNG_UST_CONTEXT_UTS_NS:
1609                 return lttng_add_uts_ns_to_ctx(ctx);
1610         case LTTNG_UST_CONTEXT_VUID:
1611                 return lttng_add_vuid_to_ctx(ctx);
1612         case LTTNG_UST_CONTEXT_VEUID:
1613                 return lttng_add_veuid_to_ctx(ctx);
1614         case LTTNG_UST_CONTEXT_VSUID:
1615                 return lttng_add_vsuid_to_ctx(ctx);
1616         case LTTNG_UST_CONTEXT_VGID:
1617                 return lttng_add_vgid_to_ctx(ctx);
1618         case LTTNG_UST_CONTEXT_VEGID:
1619                 return lttng_add_vegid_to_ctx(ctx);
1620         case LTTNG_UST_CONTEXT_VSGID:
1621                 return lttng_add_vsgid_to_ctx(ctx);
1622         default:
1623                 return -EINVAL;
1624         }
1625 }
1626
1627 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1628                 struct lttng_ust_context *context_param)
1629 {
1630         return -ENOSYS;
1631 }
1632
1633 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1634 {
1635         if (!event_enabler) {
1636                 return;
1637         }
1638         cds_list_del(&event_enabler->node);
1639
1640         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1641
1642         lttng_destroy_context(event_enabler->ctx);
1643         free(event_enabler);
1644 }
1645
1646 /*
1647  * lttng_session_sync_event_enablers should be called just before starting a
1648  * session.
1649  */
1650 static
1651 void lttng_session_sync_event_enablers(struct lttng_session *session)
1652 {
1653         struct lttng_event_enabler *event_enabler;
1654         struct lttng_event *event;
1655
1656         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1657                 lttng_event_enabler_ref_events(event_enabler);
1658         /*
1659          * For each event, if at least one of its enablers is enabled,
1660          * and its channel and session transient states are enabled, we
1661          * enable the event, else we disable it.
1662          */
1663         cds_list_for_each_entry(event, &session->events_head, node) {
1664                 struct lttng_enabler_ref *enabler_ref;
1665                 struct lttng_bytecode_runtime *runtime;
1666                 int enabled = 0, has_enablers_without_bytecode = 0;
1667
1668                 /* Enable events */
1669                 cds_list_for_each_entry(enabler_ref,
1670                                 &event->enablers_ref_head, node) {
1671                         if (enabler_ref->ref->enabled) {
1672                                 enabled = 1;
1673                                 break;
1674                         }
1675                 }
1676                 /*
1677                  * Enabled state is based on union of enablers, with
1678                  * intesection of session and channel transient enable
1679                  * states.
1680                  */
1681                 enabled = enabled && session->tstate && event->chan->tstate;
1682
1683                 CMM_STORE_SHARED(event->enabled, enabled);
1684                 /*
1685                  * Sync tracepoint registration with event enabled
1686                  * state.
1687                  */
1688                 if (enabled) {
1689                         if (!event->registered)
1690                                 register_event(event);
1691                 } else {
1692                         if (event->registered)
1693                                 unregister_event(event);
1694                 }
1695
1696                 /* Check if has enablers without bytecode enabled */
1697                 cds_list_for_each_entry(enabler_ref,
1698                                 &event->enablers_ref_head, node) {
1699                         if (enabler_ref->ref->enabled
1700                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1701                                 has_enablers_without_bytecode = 1;
1702                                 break;
1703                         }
1704                 }
1705                 event->has_enablers_without_bytecode =
1706                         has_enablers_without_bytecode;
1707
1708                 /* Enable filters */
1709                 cds_list_for_each_entry(runtime,
1710                                 &event->filter_bytecode_runtime_head, node) {
1711                         lttng_bytecode_filter_sync_state(runtime);
1712                 }
1713         }
1714         __tracepoint_probe_prune_release_queue();
1715 }
1716
1717 /* Support for event notifier is introduced by probe provider major version 2. */
1718 static
1719 bool lttng_ust_probe_supports_event_notifier(struct lttng_probe_desc *probe_desc)
1720 {
1721         return probe_desc->major >= 2;
1722 }
1723
1724 static
1725 void lttng_create_event_notifier_if_missing(
1726                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1727 {
1728         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1729         struct lttng_probe_desc *probe_desc;
1730         struct cds_list_head *probe_list;
1731         int i;
1732
1733         probe_list = lttng_get_probe_list_head();
1734
1735         cds_list_for_each_entry(probe_desc, probe_list, head) {
1736                 for (i = 0; i < probe_desc->nr_events; i++) {
1737                         int ret;
1738                         bool found = false;
1739                         const struct lttng_event_desc *desc;
1740                         struct lttng_event_notifier *event_notifier;
1741                         struct cds_hlist_head *head;
1742                         struct cds_hlist_node *node;
1743
1744                         desc = probe_desc->event_desc[i];
1745
1746                         if (!lttng_desc_match_enabler(desc,
1747                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1748                                 continue;
1749
1750                         /*
1751                          * Given the current event_notifier group, get the bucket that
1752                          * the target event_notifier would be if it was already
1753                          * created.
1754                          */
1755                         head = borrow_hash_table_bucket(
1756                                 event_notifier_group->event_notifiers_ht.table,
1757                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1758
1759                         cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
1760                                 /*
1761                                  * Check if event_notifier already exists by checking
1762                                  * if the event_notifier and enabler share the same
1763                                  * description and id.
1764                                  */
1765                                 if (event_notifier->desc == desc &&
1766                                                 event_notifier->user_token == event_notifier_enabler->user_token) {
1767                                         found = true;
1768                                         break;
1769                                 }
1770                         }
1771
1772                         if (found)
1773                                 continue;
1774
1775                         /* Check that the probe supports event notifiers, else report the error. */
1776                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1777                                 ERR("Probe \"%s\" contains event \"%s\" which matches an enabled event notifier, "
1778                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1779                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1780                                         "this event will not generate any notification.",
1781                                         probe_desc->provider,
1782                                         desc->name,
1783                                         probe_desc->major,
1784                                         probe_desc->minor);
1785                                 continue;
1786                         }
1787                         /*
1788                          * We need to create a event_notifier for this event probe.
1789                          */
1790                         ret = lttng_event_notifier_create(desc,
1791                                 event_notifier_enabler->user_token,
1792                                 event_notifier_enabler->error_counter_index,
1793                                 event_notifier_group);
1794                         if (ret) {
1795                                 DBG("Unable to create event_notifier %s, error %d\n",
1796                                         probe_desc->event_desc[i]->name, ret);
1797                         }
1798                 }
1799         }
1800 }
1801
1802 /*
1803  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1804  */
1805 static
1806 int lttng_event_notifier_enabler_ref_event_notifiers(
1807                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1808 {
1809         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1810         struct lttng_event_notifier *event_notifier;
1811
1812          /*
1813           * Only try to create event_notifiers for enablers that are enabled, the user
1814           * might still be attaching filter or exclusion to the
1815           * event_notifier_enabler.
1816           */
1817         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1818                 goto end;
1819
1820         /* First, ensure that probe event_notifiers are created for this enabler. */
1821         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1822
1823         /* Link the created event_notifier with its associated enabler. */
1824         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1825                 struct lttng_enabler_ref *enabler_ref;
1826
1827                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
1828                         continue;
1829
1830                 enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
1831                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1832                 if (!enabler_ref) {
1833                         /*
1834                          * If no backward ref, create it.
1835                          * Add backward ref from event_notifier to enabler.
1836                          */
1837                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1838                         if (!enabler_ref)
1839                                 return -ENOMEM;
1840
1841                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1842                                 event_notifier_enabler);
1843                         cds_list_add(&enabler_ref->node,
1844                                 &event_notifier->enablers_ref_head);
1845                 }
1846
1847                 /*
1848                  * Link filter bytecodes if not linked yet.
1849                  */
1850                 lttng_enabler_link_bytecode(event_notifier->desc,
1851                         &event_notifier_group->ctx,
1852                         &event_notifier->filter_bytecode_runtime_head,
1853                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1854
1855                 /*
1856                  * Link capture bytecodes if not linked yet.
1857                  */
1858                 lttng_enabler_link_bytecode(event_notifier->desc,
1859                         &event_notifier_group->ctx, &event_notifier->capture_bytecode_runtime_head,
1860                         &event_notifier_enabler->capture_bytecode_head);
1861
1862                 event_notifier->num_captures = event_notifier_enabler->num_captures;
1863         }
1864 end:
1865         return 0;
1866 }
1867
1868 static
1869 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1870 {
1871         struct lttng_event_notifier_enabler *event_notifier_enabler;
1872         struct lttng_event_notifier *event_notifier;
1873
1874         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1875                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1876
1877         /*
1878          * For each event_notifier, if at least one of its enablers is enabled,
1879          * we enable the event_notifier, else we disable it.
1880          */
1881         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1882                 struct lttng_enabler_ref *enabler_ref;
1883                 struct lttng_bytecode_runtime *runtime;
1884                 int enabled = 0, has_enablers_without_bytecode = 0;
1885
1886                 /* Enable event_notifiers */
1887                 cds_list_for_each_entry(enabler_ref,
1888                                 &event_notifier->enablers_ref_head, node) {
1889                         if (enabler_ref->ref->enabled) {
1890                                 enabled = 1;
1891                                 break;
1892                         }
1893                 }
1894
1895                 CMM_STORE_SHARED(event_notifier->enabled, enabled);
1896                 /*
1897                  * Sync tracepoint registration with event_notifier enabled
1898                  * state.
1899                  */
1900                 if (enabled) {
1901                         if (!event_notifier->registered)
1902                                 register_event_notifier(event_notifier);
1903                 } else {
1904                         if (event_notifier->registered)
1905                                 unregister_event_notifier(event_notifier);
1906                 }
1907
1908                 /* Check if has enablers without bytecode enabled */
1909                 cds_list_for_each_entry(enabler_ref,
1910                                 &event_notifier->enablers_ref_head, node) {
1911                         if (enabler_ref->ref->enabled
1912                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1913                                 has_enablers_without_bytecode = 1;
1914                                 break;
1915                         }
1916                 }
1917                 event_notifier->has_enablers_without_bytecode =
1918                         has_enablers_without_bytecode;
1919
1920                 /* Enable filters */
1921                 cds_list_for_each_entry(runtime,
1922                                 &event_notifier->filter_bytecode_runtime_head, node) {
1923                         lttng_bytecode_filter_sync_state(runtime);
1924                 }
1925
1926                 /* Enable captures. */
1927                 cds_list_for_each_entry(runtime,
1928                                 &event_notifier->capture_bytecode_runtime_head, node) {
1929                         lttng_bytecode_capture_sync_state(runtime);
1930                 }
1931         }
1932         __tracepoint_probe_prune_release_queue();
1933 }
1934
1935 /*
1936  * Apply enablers to session events, adding events to session if need
1937  * be. It is required after each modification applied to an active
1938  * session, and right before session "start".
1939  * "lazy" sync means we only sync if required.
1940  */
1941 static
1942 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1943 {
1944         /* We can skip if session is not active */
1945         if (!session->active)
1946                 return;
1947         lttng_session_sync_event_enablers(session);
1948 }
1949
1950 /*
1951  * Update all sessions with the given app context.
1952  * Called with ust lock held.
1953  * This is invoked when an application context gets loaded/unloaded. It
1954  * ensures the context callbacks are in sync with the application
1955  * context (either app context callbacks, or dummy callbacks).
1956  */
1957 void lttng_ust_context_set_session_provider(const char *name,
1958                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1959                 void (*record)(struct lttng_ctx_field *field,
1960                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1961                         struct lttng_channel *chan),
1962                 void (*get_value)(struct lttng_ctx_field *field,
1963                         struct lttng_ctx_value *value))
1964 {
1965         struct lttng_session *session;
1966
1967         cds_list_for_each_entry(session, &sessions, node) {
1968                 struct lttng_channel *chan;
1969                 struct lttng_event *event;
1970                 int ret;
1971
1972                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1973                                 name, get_size, record, get_value);
1974                 if (ret)
1975                         abort();
1976                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1977                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1978                                         name, get_size, record, get_value);
1979                         if (ret)
1980                                 abort();
1981                 }
1982                 cds_list_for_each_entry(event, &session->events_head, node) {
1983                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1984                                         name, get_size, record, get_value);
1985                         if (ret)
1986                                 abort();
1987                 }
1988         }
1989 }
1990
1991 /*
1992  * Update all event_notifier groups with the given app context.
1993  * Called with ust lock held.
1994  * This is invoked when an application context gets loaded/unloaded. It
1995  * ensures the context callbacks are in sync with the application
1996  * context (either app context callbacks, or dummy callbacks).
1997  */
1998 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
1999                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
2000                 void (*record)(struct lttng_ctx_field *field,
2001                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
2002                         struct lttng_channel *chan),
2003                 void (*get_value)(struct lttng_ctx_field *field,
2004                         struct lttng_ctx_value *value))
2005 {
2006         struct lttng_event_notifier_group *event_notifier_group;
2007
2008         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2009                 int ret;
2010
2011                 ret = lttng_ust_context_set_provider_rcu(
2012                                 &event_notifier_group->ctx,
2013                                 name, get_size, record, get_value);
2014                 if (ret)
2015                         abort();
2016         }
2017 }