liblttng-ust/lttng-events.c

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