src/lib/lttng-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 "common/logging.h"
  36 #include "common/macros.h"
  37 #include <lttng/ust-ctl.h>
  38 #include "common/ustcomm.h"
  39 #include "common/ust-fd.h"
  40 #include "common/dynamic-type.h"
  41 #include "common/ust-context-provider.h"
  42
  43 #include "common/tracepoint.h"
  44 #include "common/strutils.h"
  45 #include "lttng-bytecode.h"
  46 #include "common/tracer.h"
  47 #include "lttng-tracer-core.h"
  48 #include "lttng-ust-statedump.h"
  49 #include "context-internal.h"
  50 #include "lib/lttng-ust/events.h"
  51 #include "common/ringbuffer/shm.h"
  52 #include "common/ringbuffer/frontend_types.h"
  53 #include "common/ringbuffer/frontend.h"
  54 #include "common/counter/counter.h"
  55 #include "common/jhash.h"
  56 #include <lttng/ust-abi.h>
  57 #include "context-provider-internal.h"
  58
  59 /*
  60  * All operations within this file are called by the communication
  61  * thread, under ust_lock protection.
  62  */
  63
  64 static CDS_LIST_HEAD(sessions);
  65 static CDS_LIST_HEAD(event_notifier_groups);
  66
  67 struct cds_list_head *lttng_get_sessions(void)
  68 {
  69         return &sessions;
  70 }
  71
  72 static void _lttng_event_destroy(struct lttng_ust_event_common *event);
  73 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  74
  75 static
  76 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session);
  77 static
  78 void lttng_session_sync_event_enablers(struct lttng_ust_session *session);
  79 static
  80 void lttng_event_notifier_group_sync_enablers(
  81                 struct lttng_event_notifier_group *event_notifier_group);
  82 static
  83 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  84
  85 bool lttng_ust_validate_event_name(const struct lttng_ust_event_desc *desc)
  86 {
  87         if (strlen(desc->probe_desc->provider_name) + 1 +
  88                         strlen(desc->event_name) >= LTTNG_UST_ABI_SYM_NAME_LEN)
  89                 return false;
  90         return true;
  91 }
  92
  93 void lttng_ust_format_event_name(const struct lttng_ust_event_desc *desc,
  94                 char *name)
  95 {
  96         strcpy(name, desc->probe_desc->provider_name);
  97         strcat(name, ":");
  98         strcat(name, desc->event_name);
  99 }
 100
 101 static
 102 void lttng_event_enabler_unsync(struct lttng_event_enabler *event_enabler)
 103 {
 104         cds_list_move(&event_enabler->node,
 105                       &event_enabler->chan->parent->session->priv->unsync_enablers_head);
 106 }
 107
 108 static
 109 void lttng_session_unsync_enablers(struct lttng_ust_session *session)
 110 {
 111         cds_list_splice(&session->priv->sync_enablers_head,
 112                         &session->priv->unsync_enablers_head);
 113         CDS_INIT_LIST_HEAD(&session->priv->sync_enablers_head);
 114 }
 115
 116 static
 117 void lttng_event_notifier_enabler_unsync(struct lttng_event_notifier_enabler *event_notifier_enabler)
 118 {
 119         cds_list_move(&event_notifier_enabler->node,
 120                       &event_notifier_enabler->group->unsync_enablers_head);
 121 }
 122
 123 static
 124 void lttng_event_notifier_group_unsync_enablers(struct lttng_event_notifier_group *event_notifier_group)
 125 {
 126         cds_list_splice(&event_notifier_group->sync_enablers_head,
 127                         &event_notifier_group->unsync_enablers_head);
 128         CDS_INIT_LIST_HEAD(&event_notifier_group->sync_enablers_head);
 129 }
 130
 131 /*
 132  * Called with ust lock held.
 133  */
 134 int lttng_session_active(void)
 135 {
 136         struct lttng_ust_session_private *iter;
 137
 138         cds_list_for_each_entry(iter, &sessions, node) {
 139                 if (iter->pub->active)
 140                         return 1;
 141         }
 142         return 0;
 143 }
 144
 145 static
 146 int lttng_loglevel_match(int loglevel,
 147                 unsigned int has_loglevel,
 148                 enum lttng_ust_abi_loglevel_type req_type,
 149                 int req_loglevel)
 150 {
 151         if (!has_loglevel)
 152                 loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
 153         switch (req_type) {
 154         case LTTNG_UST_ABI_LOGLEVEL_RANGE:
 155                 if (loglevel <= req_loglevel
 156                                 || (req_loglevel == -1 && loglevel <= LTTNG_UST_TRACEPOINT_LOGLEVEL_DEBUG))
 157                         return 1;
 158                 else
 159                         return 0;
 160         case LTTNG_UST_ABI_LOGLEVEL_SINGLE:
 161                 if (loglevel == req_loglevel
 162                                 || (req_loglevel == -1 && loglevel <= LTTNG_UST_TRACEPOINT_LOGLEVEL_DEBUG))
 163                         return 1;
 164                 else
 165                         return 0;
 166         case LTTNG_UST_ABI_LOGLEVEL_ALL:
 167         default:
 168                 if (loglevel <= LTTNG_UST_TRACEPOINT_LOGLEVEL_DEBUG)
 169                         return 1;
 170                 else
 171                         return 0;
 172         }
 173 }
 174
 175 struct lttng_ust_session *lttng_session_create(void)
 176 {
 177         struct lttng_ust_session *session;
 178         struct lttng_ust_session_private *session_priv;
 179         int i;
 180
 181         session = zmalloc(sizeof(struct lttng_ust_session));
 182         if (!session)
 183                 return NULL;
 184         session->struct_size = sizeof(struct lttng_ust_session);
 185         session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
 186         if (!session_priv) {
 187                 free(session);
 188                 return NULL;
 189         }
 190         session->priv = session_priv;
 191         session_priv->pub = session;
 192         if (lttng_context_init_all(&session->priv->ctx)) {
 193                 free(session_priv);
 194                 free(session);
 195                 return NULL;
 196         }
 197         CDS_INIT_LIST_HEAD(&session->priv->chan_head);
 198         CDS_INIT_LIST_HEAD(&session->priv->events_head);
 199         CDS_INIT_LIST_HEAD(&session->priv->enums_head);
 200         CDS_INIT_LIST_HEAD(&session->priv->unsync_enablers_head);
 201         CDS_INIT_LIST_HEAD(&session->priv->sync_enablers_head);
 202         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 203                 CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 204         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 205                 CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
 206         cds_list_add(&session->priv->node, &sessions);
 207         return session;
 208 }
 209
 210 struct lttng_counter *lttng_ust_counter_create(
 211                 const char *counter_transport_name,
 212                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 213 {
 214         struct lttng_counter_transport *counter_transport = NULL;
 215         struct lttng_counter *counter = NULL;
 216
 217         counter_transport = lttng_counter_transport_find(counter_transport_name);
 218         if (!counter_transport)
 219                 goto notransport;
 220         counter = zmalloc(sizeof(struct lttng_counter));
 221         if (!counter)
 222                 goto nomem;
 223
 224         counter->ops = &counter_transport->ops;
 225         counter->transport = counter_transport;
 226
 227         counter->counter = counter->ops->counter_create(
 228                         number_dimensions, dimensions, 0,
 229                         -1, 0, NULL, false);
 230         if (!counter->counter) {
 231                 goto create_error;
 232         }
 233
 234         return counter;
 235
 236 create_error:
 237         free(counter);
 238 nomem:
 239 notransport:
 240         return NULL;
 241 }
 242
 243 static
 244 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 245 {
 246         counter->ops->counter_destroy(counter->counter);
 247         free(counter);
 248 }
 249
 250 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 251 {
 252         struct lttng_event_notifier_group *event_notifier_group;
 253         int i;
 254
 255         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 256         if (!event_notifier_group)
 257                 return NULL;
 258
 259         /* Add all contexts. */
 260         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 261                 free(event_notifier_group);
 262                 return NULL;
 263         }
 264
 265         CDS_INIT_LIST_HEAD(&event_notifier_group->sync_enablers_head);
 266         CDS_INIT_LIST_HEAD(&event_notifier_group->unsync_enablers_head);
 267         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 268         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 269                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 270
 271         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 272
 273         return event_notifier_group;
 274 }
 275
 276 /*
 277  * Only used internally at session destruction.
 278  */
 279 static
 280 void _lttng_channel_unmap(struct lttng_ust_channel_buffer *lttng_chan)
 281 {
 282         struct lttng_ust_ring_buffer_channel *chan;
 283         struct lttng_ust_shm_handle *handle;
 284
 285         cds_list_del(&lttng_chan->priv->node);
 286         lttng_destroy_context(lttng_chan->priv->ctx);
 287         chan = lttng_chan->priv->rb_chan;
 288         handle = chan->handle;
 289         channel_destroy(chan, handle, 0);
 290         free(lttng_chan->parent);
 291         free(lttng_chan->priv);
 292         free(lttng_chan);
 293 }
 294
 295 static
 296 void register_event(struct lttng_ust_event_common *event)
 297 {
 298         int ret;
 299         const struct lttng_ust_event_desc *desc;
 300
 301         assert(event->priv->registered == 0);
 302         desc = event->priv->desc;
 303         ret = lttng_ust_tp_probe_register_queue_release(desc->probe_desc->provider_name,
 304                         desc->event_name,
 305                         desc->tp_class->probe_callback,
 306                         event, desc->tp_class->signature);
 307         WARN_ON_ONCE(ret);
 308         if (!ret)
 309                 event->priv->registered = 1;
 310 }
 311
 312 static
 313 void unregister_event(struct lttng_ust_event_common *event)
 314 {
 315         int ret;
 316         const struct lttng_ust_event_desc *desc;
 317
 318         assert(event->priv->registered == 1);
 319         desc = event->priv->desc;
 320         ret = lttng_ust_tp_probe_unregister_queue_release(desc->probe_desc->provider_name,
 321                         desc->event_name,
 322                         desc->tp_class->probe_callback,
 323                         event);
 324         WARN_ON_ONCE(ret);
 325         if (!ret)
 326                 event->priv->registered = 0;
 327 }
 328
 329 static
 330 void _lttng_event_unregister(struct lttng_ust_event_common *event)
 331 {
 332         if (event->priv->registered)
 333                 unregister_event(event);
 334 }
 335
 336 void lttng_session_destroy(struct lttng_ust_session *session)
 337 {
 338         struct lttng_ust_channel_buffer_private *chan, *tmpchan;
 339         struct lttng_ust_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
 340         struct lttng_enum *_enum, *tmp_enum;
 341         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 342
 343         CMM_ACCESS_ONCE(session->active) = 0;
 344         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
 345                 _lttng_event_unregister(event_recorder_priv->parent.pub);
 346         }
 347         lttng_ust_urcu_synchronize_rcu();       /* Wait for in-flight events to complete */
 348         lttng_ust_tp_probe_prune_release_queue();
 349         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 350                         &session->priv->unsync_enablers_head, node)
 351                 lttng_event_enabler_destroy(event_enabler);
 352         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 353                         &session->priv->sync_enablers_head, node)
 354                 lttng_event_enabler_destroy(event_enabler);
 355         cds_list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv,
 356                         &session->priv->events_head, node)
 357                 _lttng_event_destroy(event_recorder_priv->parent.pub);
 358         cds_list_for_each_entry_safe(_enum, tmp_enum,
 359                         &session->priv->enums_head, node)
 360                 _lttng_enum_destroy(_enum);
 361         cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 362                 _lttng_channel_unmap(chan->pub);
 363         cds_list_del(&session->priv->node);
 364         lttng_destroy_context(session->priv->ctx);
 365         free(session->priv);
 366         free(session);
 367 }
 368
 369 void lttng_event_notifier_group_destroy(
 370                 struct lttng_event_notifier_group *event_notifier_group)
 371 {
 372         int close_ret;
 373         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 374         struct lttng_ust_event_notifier_private *event_notifier_priv, *tmpevent_notifier_priv;
 375
 376         if (!event_notifier_group) {
 377                 return;
 378         }
 379
 380         cds_list_for_each_entry(event_notifier_priv,
 381                         &event_notifier_group->event_notifiers_head, node)
 382                 _lttng_event_unregister(event_notifier_priv->parent.pub);
 383
 384         lttng_ust_urcu_synchronize_rcu();
 385
 386         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 387                         &event_notifier_group->sync_enablers_head, node)
 388                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 389         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 390                         &event_notifier_group->unsync_enablers_head, node)
 391                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 392
 393         cds_list_for_each_entry_safe(event_notifier_priv, tmpevent_notifier_priv,
 394                         &event_notifier_group->event_notifiers_head, node)
 395                 _lttng_event_destroy(event_notifier_priv->parent.pub);
 396
 397         if (event_notifier_group->error_counter)
 398                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 399
 400         /* Close the notification fd to the listener of event_notifiers. */
 401
 402         lttng_ust_lock_fd_tracker();
 403         close_ret = close(event_notifier_group->notification_fd);
 404         if (!close_ret) {
 405                 lttng_ust_delete_fd_from_tracker(
 406                                 event_notifier_group->notification_fd);
 407         } else {
 408                 PERROR("close");
 409                 abort();
 410         }
 411         lttng_ust_unlock_fd_tracker();
 412
 413         cds_list_del(&event_notifier_group->node);
 414         lttng_destroy_context(event_notifier_group->ctx);
 415         free(event_notifier_group);
 416 }
 417
 418 static
 419 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 420 {
 421         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 422         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 423
 424         if (!enabler) {
 425                 return;
 426         }
 427
 428         /* Destroy filter bytecode */
 429         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 430                         &enabler->filter_bytecode_head, node) {
 431                 free(filter_node);
 432         }
 433
 434         /* Destroy excluders */
 435         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 436                         &enabler->excluder_head, node) {
 437                 free(excluder_node);
 438         }
 439 }
 440
 441  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 442 {
 443         if (!event_notifier_enabler) {
 444                 return;
 445         }
 446
 447         cds_list_del(&event_notifier_enabler->node);
 448
 449         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 450
 451         free(event_notifier_enabler);
 452 }
 453
 454 static
 455 int lttng_enum_create(const struct lttng_ust_enum_desc *desc,
 456                 struct lttng_ust_session *session)
 457 {
 458         const char *enum_name = desc->name;
 459         struct lttng_enum *_enum;
 460         struct cds_hlist_head *head;
 461         int ret = 0;
 462         size_t name_len = strlen(enum_name);
 463         uint32_t hash;
 464         int notify_socket;
 465
 466         /* Check if this enum is already registered for this session. */
 467         hash = jhash(enum_name, name_len, 0);
 468         head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 469
 470         _enum = lttng_ust_enum_get_from_desc(session, desc);
 471         if (_enum) {
 472                 ret = -EEXIST;
 473                 goto exist;
 474         }
 475
 476         notify_socket = lttng_get_notify_socket(session->priv->owner);
 477         if (notify_socket < 0) {
 478                 ret = notify_socket;
 479                 goto socket_error;
 480         }
 481
 482         _enum = zmalloc(sizeof(*_enum));
 483         if (!_enum) {
 484                 ret = -ENOMEM;
 485                 goto cache_error;
 486         }
 487         _enum->session = session;
 488         _enum->desc = desc;
 489
 490         ret = ustcomm_register_enum(notify_socket,
 491                 session->priv->objd,
 492                 enum_name,
 493                 desc->nr_entries,
 494                 desc->entries,
 495                 &_enum->id);
 496         if (ret < 0) {
 497                 DBG("Error (%d) registering enumeration to sessiond", ret);
 498                 goto sessiond_register_error;
 499         }
 500         cds_list_add(&_enum->node, &session->priv->enums_head);
 501         cds_hlist_add_head(&_enum->hlist, head);
 502         return 0;
 503
 504 sessiond_register_error:
 505         free(_enum);
 506 cache_error:
 507 socket_error:
 508 exist:
 509         return ret;
 510 }
 511
 512 static
 513 int lttng_create_enum_check(const struct lttng_ust_type_common *type,
 514                 struct lttng_ust_session *session)
 515 {
 516         switch (type->type) {
 517         case lttng_ust_type_enum:
 518         {
 519                 const struct lttng_ust_enum_desc *enum_desc;
 520                 int ret;
 521
 522                 enum_desc = lttng_ust_get_type_enum(type)->desc;
 523                 ret = lttng_enum_create(enum_desc, session);
 524                 if (ret && ret != -EEXIST) {
 525                         DBG("Unable to create enum error: (%d)", ret);
 526                         return ret;
 527                 }
 528                 break;
 529         }
 530         case lttng_ust_type_dynamic:
 531         {
 532                 const struct lttng_ust_event_field *tag_field_generic;
 533                 const struct lttng_ust_enum_desc *enum_desc;
 534                 int ret;
 535
 536                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 537                 enum_desc = lttng_ust_get_type_enum(tag_field_generic->type)->desc;
 538                 ret = lttng_enum_create(enum_desc, session);
 539                 if (ret && ret != -EEXIST) {
 540                         DBG("Unable to create enum error: (%d)", ret);
 541                         return ret;
 542                 }
 543                 break;
 544         }
 545         default:
 546                 /* TODO: nested types when they become supported. */
 547                 break;
 548         }
 549         return 0;
 550 }
 551
 552 static
 553 int lttng_create_all_event_enums(size_t nr_fields,
 554                 const struct lttng_ust_event_field * const *event_fields,
 555                 struct lttng_ust_session *session)
 556 {
 557         size_t i;
 558         int ret;
 559
 560         /* For each field, ensure enum is part of the session. */
 561         for (i = 0; i < nr_fields; i++) {
 562                 const struct lttng_ust_type_common *type = event_fields[i]->type;
 563
 564                 ret = lttng_create_enum_check(type, session);
 565                 if (ret)
 566                         return ret;
 567         }
 568         return 0;
 569 }
 570
 571 static
 572 int lttng_create_all_ctx_enums(size_t nr_fields,
 573                 struct lttng_ust_ctx_field *ctx_fields,
 574                 struct lttng_ust_session *session)
 575 {
 576         size_t i;
 577         int ret;
 578
 579         /* For each field, ensure enum is part of the session. */
 580         for (i = 0; i < nr_fields; i++) {
 581                 const struct lttng_ust_type_common *type = ctx_fields[i].event_field->type;
 582
 583                 ret = lttng_create_enum_check(type, session);
 584                 if (ret)
 585                         return ret;
 586         }
 587         return 0;
 588 }
 589
 590 /*
 591  * Ensure that a state-dump will be performed for this session at the end
 592  * of the current handle_message().
 593  */
 594 int lttng_session_statedump(struct lttng_ust_session *session)
 595 {
 596         session->priv->statedump_pending = 1;
 597         lttng_ust_sockinfo_session_enabled(session->priv->owner);
 598         return 0;
 599 }
 600
 601 int lttng_session_enable(struct lttng_ust_session *session)
 602 {
 603         int ret = 0;
 604         struct lttng_ust_channel_buffer_private *chan;
 605         int notify_socket;
 606
 607         if (session->active) {
 608                 ret = -EBUSY;
 609                 goto end;
 610         }
 611
 612         notify_socket = lttng_get_notify_socket(session->priv->owner);
 613         if (notify_socket < 0)
 614                 return notify_socket;
 615
 616         /* Set transient enabler state to "enabled" */
 617         session->priv->tstate = 1;
 618
 619         /* We need to sync enablers with session before activation. */
 620         lttng_session_sync_event_enablers(session);
 621
 622         /*
 623          * Snapshot the number of events per channel to know the type of header
 624          * we need to use.
 625          */
 626         cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 627                 struct lttng_ust_ctx *ctx;
 628                 struct lttng_ust_ctx_field *fields = NULL;
 629                 size_t nr_fields = 0;
 630                 uint32_t chan_id;
 631
 632                 /* don't change it if session stop/restart */
 633                 if (chan->header_type)
 634                         continue;
 635                 ctx = chan->ctx;
 636                 if (ctx) {
 637                         nr_fields = ctx->nr_fields;
 638                         fields = ctx->fields;
 639                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 640                                 session);
 641                         if (ret < 0) {
 642                                 DBG("Error (%d) adding enum to session", ret);
 643                                 return ret;
 644                         }
 645                 }
 646                 ret = ustcomm_register_channel(notify_socket,
 647                         session,
 648                         session->priv->objd,
 649                         chan->parent.objd,
 650                         nr_fields,
 651                         fields,
 652                         &chan_id,
 653                         &chan->header_type);
 654                 if (ret) {
 655                         DBG("Error (%d) registering channel to sessiond", ret);
 656                         return ret;
 657                 }
 658                 if (chan_id != chan->id) {
 659                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 660                                 chan_id, chan->id);
 661                         return -EINVAL;
 662                 }
 663         }
 664
 665         /* Set atomically the state to "active" */
 666         CMM_ACCESS_ONCE(session->active) = 1;
 667         CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 668
 669         ret = lttng_session_statedump(session);
 670         if (ret)
 671                 return ret;
 672 end:
 673         return ret;
 674 }
 675
 676 int lttng_session_disable(struct lttng_ust_session *session)
 677 {
 678         int ret = 0;
 679
 680         if (!session->active) {
 681                 ret = -EBUSY;
 682                 goto end;
 683         }
 684         /* Set atomically the state to "inactive" */
 685         CMM_ACCESS_ONCE(session->active) = 0;
 686
 687         /* Set transient enabler state to "disabled" */
 688         session->priv->tstate = 0;
 689         lttng_session_sync_event_enablers(session);
 690 end:
 691         return ret;
 692 }
 693
 694 int lttng_channel_enable(struct lttng_ust_channel_common *lttng_channel)
 695 {
 696         int ret = 0;
 697
 698         if (lttng_channel->enabled) {
 699                 ret = -EBUSY;
 700                 goto end;
 701         }
 702         /* Set transient enabler state to "enabled" */
 703         lttng_channel->priv->tstate = 1;
 704         lttng_session_sync_event_enablers(lttng_channel->session);
 705         /* Set atomically the state to "enabled" */
 706         CMM_ACCESS_ONCE(lttng_channel->enabled) = 1;
 707 end:
 708         return ret;
 709 }
 710
 711 int lttng_channel_disable(struct lttng_ust_channel_common *lttng_channel)
 712 {
 713         int ret = 0;
 714
 715         if (!lttng_channel->enabled) {
 716                 ret = -EBUSY;
 717                 goto end;
 718         }
 719         /* Set atomically the state to "disabled" */
 720         CMM_ACCESS_ONCE(lttng_channel->enabled) = 0;
 721         /* Set transient enabler state to "enabled" */
 722         lttng_channel->priv->tstate = 0;
 723         lttng_session_sync_event_enablers(lttng_channel->session);
 724 end:
 725         return ret;
 726 }
 727
 728 static inline
 729 struct cds_hlist_head *borrow_hash_table_bucket(
 730                 struct cds_hlist_head *hash_table,
 731                 unsigned int hash_table_size,
 732                 const struct lttng_ust_event_desc *desc)
 733 {
 734         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 735         size_t name_len;
 736         uint32_t hash;
 737
 738         lttng_ust_format_event_name(desc, name);
 739         name_len = strlen(name);
 740
 741         hash = jhash(name, name_len, 0);
 742         return &hash_table[hash & (hash_table_size - 1)];
 743 }
 744
 745 /*
 746  * Supports event creation while tracing session is active.
 747  */
 748 static
 749 int lttng_event_recorder_create(const struct lttng_ust_event_desc *desc,
 750                 struct lttng_ust_channel_buffer *chan)
 751 {
 752         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 753         struct lttng_ust_event_recorder *event_recorder;
 754         struct lttng_ust_event_recorder_private *event_recorder_priv;
 755         struct lttng_ust_session *session = chan->parent->session;
 756         struct cds_hlist_head *head;
 757         int ret = 0;
 758         int notify_socket, loglevel;
 759         const char *uri;
 760
 761         head = borrow_hash_table_bucket(chan->parent->session->priv->events_ht.table,
 762                 LTTNG_UST_EVENT_HT_SIZE, desc);
 763
 764         notify_socket = lttng_get_notify_socket(session->priv->owner);
 765         if (notify_socket < 0) {
 766                 ret = notify_socket;
 767                 goto socket_error;
 768         }
 769
 770         ret = lttng_create_all_event_enums(desc->tp_class->nr_fields, desc->tp_class->fields,
 771                         session);
 772         if (ret < 0) {
 773                 DBG("Error (%d) adding enum to session", ret);
 774                 goto create_enum_error;
 775         }
 776
 777         /*
 778          * Check if loglevel match. Refuse to connect event if not.
 779          */
 780         event_recorder = zmalloc(sizeof(struct lttng_ust_event_recorder));
 781         if (!event_recorder) {
 782                 ret = -ENOMEM;
 783                 goto cache_error;
 784         }
 785         event_recorder->struct_size = sizeof(struct lttng_ust_event_recorder);
 786
 787         event_recorder->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 788         if (!event_recorder->parent) {
 789                 ret = -ENOMEM;
 790                 goto parent_error;
 791         }
 792         event_recorder->parent->struct_size = sizeof(struct lttng_ust_event_common);
 793         event_recorder->parent->type = LTTNG_UST_EVENT_TYPE_RECORDER;
 794         event_recorder->parent->child = event_recorder;
 795
 796         event_recorder_priv = zmalloc(sizeof(struct lttng_ust_event_recorder_private));
 797         if (!event_recorder_priv) {
 798                 ret = -ENOMEM;
 799                 goto priv_error;
 800         }
 801         event_recorder->priv = event_recorder_priv;
 802         event_recorder_priv->pub = event_recorder;
 803         event_recorder->parent->priv = &event_recorder_priv->parent;
 804         event_recorder_priv->parent.pub = event_recorder->parent;
 805
 806         event_recorder->chan = chan;
 807
 808         /* Event will be enabled by enabler sync. */
 809         event_recorder->parent->run_filter = lttng_ust_interpret_event_filter;
 810         event_recorder->parent->enabled = 0;
 811         event_recorder->parent->priv->registered = 0;
 812         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->filter_bytecode_runtime_head);
 813         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 814         event_recorder->parent->priv->desc = desc;
 815
 816         if (desc->loglevel)
 817                 loglevel = *(*desc->loglevel);
 818         else
 819                 loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
 820         if (desc->model_emf_uri)
 821                 uri = *(desc->model_emf_uri);
 822         else
 823                 uri = NULL;
 824
 825         lttng_ust_format_event_name(desc, name);
 826
 827         /* Fetch event ID from sessiond */
 828         ret = ustcomm_register_event(notify_socket,
 829                 session,
 830                 session->priv->objd,
 831                 chan->priv->parent.objd,
 832                 name,
 833                 loglevel,
 834                 desc->tp_class->signature,
 835                 desc->tp_class->nr_fields,
 836                 desc->tp_class->fields,
 837                 uri,
 838                 &event_recorder->priv->id);
 839         if (ret < 0) {
 840                 DBG("Error (%d) registering event to sessiond", ret);
 841                 goto sessiond_register_error;
 842         }
 843
 844         cds_list_add(&event_recorder_priv->node, &chan->parent->session->priv->events_head);
 845         cds_hlist_add_head(&event_recorder_priv->hlist, head);
 846         return 0;
 847
 848 sessiond_register_error:
 849         free(event_recorder_priv);
 850 priv_error:
 851         free(event_recorder->parent);
 852 parent_error:
 853         free(event_recorder);
 854 cache_error:
 855 create_enum_error:
 856 socket_error:
 857         return ret;
 858 }
 859
 860 static
 861 int lttng_event_notifier_create(const struct lttng_ust_event_desc *desc,
 862                 uint64_t token, uint64_t error_counter_index,
 863                 struct lttng_event_notifier_group *event_notifier_group)
 864 {
 865         struct lttng_ust_event_notifier *event_notifier;
 866         struct lttng_ust_event_notifier_private *event_notifier_priv;
 867         struct cds_hlist_head *head;
 868         int ret = 0;
 869
 870         /*
 871          * Get the hashtable bucket the created lttng_event_notifier object
 872          * should be inserted.
 873          */
 874         head = borrow_hash_table_bucket(
 875                 event_notifier_group->event_notifiers_ht.table,
 876                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 877
 878         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 879         if (!event_notifier) {
 880                 ret = -ENOMEM;
 881                 goto error;
 882         }
 883         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 884
 885         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 886         if (!event_notifier->parent) {
 887                 ret = -ENOMEM;
 888                 goto parent_error;
 889         }
 890         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 891         event_notifier->parent->type = LTTNG_UST_EVENT_TYPE_NOTIFIER;
 892         event_notifier->parent->child = event_notifier;
 893
 894         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 895         if (!event_notifier_priv) {
 896                 ret = -ENOMEM;
 897                 goto priv_error;
 898         }
 899         event_notifier->priv = event_notifier_priv;
 900         event_notifier_priv->pub = event_notifier;
 901         event_notifier->parent->priv = &event_notifier_priv->parent;
 902         event_notifier_priv->parent.pub = event_notifier->parent;
 903
 904         event_notifier_priv->group = event_notifier_group;
 905         event_notifier_priv->parent.user_token = token;
 906         event_notifier_priv->error_counter_index = error_counter_index;
 907
 908         /* Event notifier will be enabled by enabler sync. */
 909         event_notifier->parent->run_filter = lttng_ust_interpret_event_filter;
 910         event_notifier->parent->enabled = 0;
 911         event_notifier_priv->parent.registered = 0;
 912
 913         CDS_INIT_LIST_HEAD(&event_notifier->parent->priv->filter_bytecode_runtime_head);
 914         CDS_INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
 915         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 916         event_notifier_priv->parent.desc = desc;
 917         event_notifier->notification_send = lttng_event_notifier_notification_send;
 918
 919         cds_list_add(&event_notifier_priv->node,
 920                         &event_notifier_group->event_notifiers_head);
 921         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 922
 923         return 0;
 924
 925 priv_error:
 926         free(event_notifier->parent);
 927 parent_error:
 928         free(event_notifier);
 929 error:
 930         return ret;
 931 }
 932
 933 static
 934 int lttng_desc_match_star_glob_enabler(const struct lttng_ust_event_desc *desc,
 935                 struct lttng_enabler *enabler)
 936 {
 937         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 938         int loglevel = 0;
 939         unsigned int has_loglevel = 0;
 940
 941         lttng_ust_format_event_name(desc, name);
 942         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 943         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 944                         name, SIZE_MAX))
 945                 return 0;
 946         if (desc->loglevel) {
 947                 loglevel = *(*desc->loglevel);
 948                 has_loglevel = 1;
 949         }
 950         if (!lttng_loglevel_match(loglevel,
 951                         has_loglevel,
 952                         enabler->event_param.loglevel_type,
 953                         enabler->event_param.loglevel))
 954                 return 0;
 955         return 1;
 956 }
 957
 958 static
 959 int lttng_desc_match_event_enabler(const struct lttng_ust_event_desc *desc,
 960                 struct lttng_enabler *enabler)
 961 {
 962         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 963         int loglevel = 0;
 964         unsigned int has_loglevel = 0;
 965
 966         lttng_ust_format_event_name(desc, name);
 967         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 968         if (strcmp(name, enabler->event_param.name))
 969                 return 0;
 970         if (desc->loglevel) {
 971                 loglevel = *(*desc->loglevel);
 972                 has_loglevel = 1;
 973         }
 974         if (!lttng_loglevel_match(loglevel,
 975                         has_loglevel,
 976                         enabler->event_param.loglevel_type,
 977                         enabler->event_param.loglevel))
 978                 return 0;
 979         return 1;
 980 }
 981
 982 static
 983 int lttng_desc_match_enabler(const struct lttng_ust_event_desc *desc,
 984                 struct lttng_enabler *enabler)
 985 {
 986         switch (enabler->format_type) {
 987         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 988         {
 989                 struct lttng_ust_excluder_node *excluder;
 990
 991                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 992                         return 0;
 993                 }
 994
 995                 /*
 996                  * If the matching event matches with an excluder,
 997                  * return 'does not match'
 998                  */
 999                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
1000                         int count;
1001
1002                         for (count = 0; count < excluder->excluder.count; count++) {
1003                                 int len;
1004                                 char *excluder_name;
1005
1006                                 excluder_name = (char *) (excluder->excluder.names)
1007                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
1008                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1009                                 if (len > 0) {
1010                                         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
1011
1012                                         lttng_ust_format_event_name(desc, name);
1013                                         if (strutils_star_glob_match(excluder_name, len, name, SIZE_MAX)) {
1014                                                 return 0;
1015                                         }
1016                                 }
1017                         }
1018                 }
1019                 return 1;
1020         }
1021         case LTTNG_ENABLER_FORMAT_EVENT:
1022                 return lttng_desc_match_event_enabler(desc, enabler);
1023         default:
1024                 return -EINVAL;
1025         }
1026 }
1027
1028 static
1029 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
1030                 struct lttng_ust_event_recorder *event_recorder)
1031 {
1032         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
1033                         lttng_event_enabler_as_enabler(event_enabler))
1034                         && event_recorder->chan == event_enabler->chan)
1035                 return 1;
1036         else
1037                 return 0;
1038 }
1039
1040 static
1041 int lttng_event_notifier_enabler_match_event_notifier(
1042                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1043                 struct lttng_ust_event_notifier *event_notifier)
1044 {
1045         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
1046                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1047
1048         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
1049                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
1050                 return 1;
1051         else
1052                 return 0;
1053 }
1054
1055 static
1056 struct lttng_enabler_ref *lttng_enabler_ref(
1057                 struct cds_list_head *enabler_ref_list,
1058                 struct lttng_enabler *enabler)
1059 {
1060         struct lttng_enabler_ref *enabler_ref;
1061
1062         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1063                 if (enabler_ref->ref == enabler)
1064                         return enabler_ref;
1065         }
1066         return NULL;
1067 }
1068
1069 /*
1070  * Create struct lttng_event if it is missing and present in the list of
1071  * tracepoint probes.
1072  */
1073 static
1074 void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_enabler)
1075 {
1076         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1077         struct lttng_ust_registered_probe *reg_probe;
1078         const struct lttng_ust_event_desc *desc;
1079         struct lttng_ust_event_recorder_private *event_recorder_priv;
1080         int i;
1081         struct cds_list_head *probe_list;
1082
1083         probe_list = lttng_get_probe_list_head();
1084         /*
1085          * For each probe event, if we find that a probe event matches
1086          * our enabler, create an associated lttng_event if not
1087          * already present.
1088          */
1089         cds_list_for_each_entry(reg_probe, probe_list, head) {
1090                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1091
1092                 for (i = 0; i < probe_desc->nr_events; i++) {
1093                         int ret;
1094                         bool found = false;
1095                         struct cds_hlist_head *head;
1096                         struct cds_hlist_node *node;
1097
1098                         desc = probe_desc->event_desc[i];
1099                         if (!lttng_desc_match_enabler(desc,
1100                                         lttng_event_enabler_as_enabler(event_enabler)))
1101                                 continue;
1102
1103                         head = borrow_hash_table_bucket(
1104                                 session->priv->events_ht.table,
1105                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1106
1107                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1108                                 if (event_recorder_priv->parent.desc == desc
1109                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1110                                         found = true;
1111                                         break;
1112                                 }
1113                         }
1114                         if (found)
1115                                 continue;
1116
1117                         /*
1118                          * We need to create an event for this
1119                          * event probe.
1120                          */
1121                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1122                                         event_enabler->chan);
1123                         if (ret) {
1124                                 DBG("Unable to create event \"%s:%s\", error %d\n",
1125                                         probe_desc->provider_name,
1126                                         probe_desc->event_desc[i]->event_name, ret);
1127                         }
1128                 }
1129         }
1130 }
1131
1132 static
1133 void probe_provider_event_for_each(const struct lttng_ust_probe_desc *provider_desc,
1134                 void (*event_func)(struct lttng_ust_event_common *event))
1135 {
1136         struct cds_hlist_node *node, *tmp_node;
1137         struct cds_list_head *sessionsp;
1138         unsigned int i;
1139
1140         /* Get handle on list of sessions. */
1141         sessionsp = lttng_get_sessions();
1142
1143         /*
1144          * Iterate over all events in the probe provider descriptions and
1145          * sessions to queue the unregistration of the events.
1146          */
1147         for (i = 0; i < provider_desc->nr_events; i++) {
1148                 const struct lttng_ust_event_desc *event_desc;
1149                 struct lttng_event_notifier_group *event_notifier_group;
1150                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1151                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1152                 struct lttng_ust_session_private *session_priv;
1153                 struct cds_hlist_head *head;
1154
1155                 event_desc = provider_desc->event_desc[i];
1156
1157                 /*
1158                  * Iterate over all session to find the current event
1159                  * description.
1160                  */
1161                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1162                         /*
1163                          * Get the list of events in the hashtable bucket and
1164                          * iterate to find the event matching this descriptor.
1165                          */
1166                         head = borrow_hash_table_bucket(
1167                                 session_priv->events_ht.table,
1168                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1169
1170                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1171                                 if (event_desc == event_recorder_priv->parent.desc) {
1172                                         event_func(event_recorder_priv->parent.pub);
1173                                         break;
1174                                 }
1175                         }
1176                 }
1177
1178                 /*
1179                  * Iterate over all event_notifier groups to find the current event
1180                  * description.
1181                  */
1182                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1183                         /*
1184                          * Get the list of event_notifiers in the hashtable bucket and
1185                          * iterate to find the event_notifier matching this
1186                          * descriptor.
1187                          */
1188                         head = borrow_hash_table_bucket(
1189                                 event_notifier_group->event_notifiers_ht.table,
1190                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1191
1192                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1193                                 if (event_desc == event_notifier_priv->parent.desc) {
1194                                         event_func(event_notifier_priv->parent.pub);
1195                                         break;
1196                                 }
1197                         }
1198                 }
1199         }
1200 }
1201
1202 static
1203 void _event_enum_destroy(struct lttng_ust_event_common *event)
1204 {
1205
1206         switch (event->type) {
1207         case LTTNG_UST_EVENT_TYPE_RECORDER:
1208         {
1209                 struct lttng_ust_event_recorder *event_recorder = event->child;
1210                 struct lttng_ust_session *session = event_recorder->chan->parent->session;
1211                 unsigned int i;
1212
1213                 /* Destroy enums of the current event. */
1214                 for (i = 0; i < event_recorder->parent->priv->desc->tp_class->nr_fields; i++) {
1215                         const struct lttng_ust_enum_desc *enum_desc;
1216                         const struct lttng_ust_event_field *field;
1217                         struct lttng_enum *curr_enum;
1218
1219                         field = event_recorder->parent->priv->desc->tp_class->fields[i];
1220                         switch (field->type->type) {
1221                         case lttng_ust_type_enum:
1222                                 enum_desc = lttng_ust_get_type_enum(field->type)->desc;
1223                                 break;
1224                         default:
1225                                 continue;
1226                         }
1227
1228                         curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1229                         if (curr_enum) {
1230                                 _lttng_enum_destroy(curr_enum);
1231                         }
1232                 }
1233                 break;
1234         }
1235         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1236                 break;
1237         default:
1238                 abort();
1239         }
1240         /* Destroy event. */
1241         _lttng_event_destroy(event);
1242 }
1243
1244 /*
1245  * Iterate over all the UST sessions to unregister and destroy all probes from
1246  * the probe provider descriptor received as argument. Must me called with the
1247  * ust_lock held.
1248  */
1249 void lttng_probe_provider_unregister_events(
1250                 const struct lttng_ust_probe_desc *provider_desc)
1251 {
1252         /*
1253          * Iterate over all events in the probe provider descriptions and sessions
1254          * to queue the unregistration of the events.
1255          */
1256         probe_provider_event_for_each(provider_desc, _lttng_event_unregister);
1257
1258         /* Wait for grace period. */
1259         lttng_ust_urcu_synchronize_rcu();
1260         /* Prune the unregistration queue. */
1261         lttng_ust_tp_probe_prune_release_queue();
1262
1263         /*
1264          * It is now safe to destroy the events and remove them from the event list
1265          * and hashtables.
1266          */
1267         probe_provider_event_for_each(provider_desc, _event_enum_destroy);
1268 }
1269
1270 /*
1271  * Create events associated with an event enabler (if not already present),
1272  * and add backward reference from the event to the enabler.
1273  */
1274 static
1275 int lttng_event_enabler_ref_event_recorders(struct lttng_event_enabler *event_enabler)
1276 {
1277         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1278         struct lttng_ust_event_recorder_private *event_recorder_priv;
1279
1280         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1281                 goto end;
1282
1283         /* First ensure that probe events are created for this enabler. */
1284         lttng_create_event_recorder_if_missing(event_enabler);
1285
1286         /* For each event matching enabler in session event list. */
1287         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1288                 struct lttng_enabler_ref *enabler_ref;
1289
1290                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1291                         continue;
1292
1293                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1294                         lttng_event_enabler_as_enabler(event_enabler));
1295                 if (!enabler_ref) {
1296                         /*
1297                          * If no backward ref, create it.
1298                          * Add backward ref from event to enabler.
1299                          */
1300                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1301                         if (!enabler_ref)
1302                                 return -ENOMEM;
1303                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1304                                 event_enabler);
1305                         cds_list_add(&enabler_ref->node,
1306                                 &event_recorder_priv->parent.enablers_ref_head);
1307                 }
1308
1309                 /*
1310                  * Link filter bytecodes if not linked yet.
1311                  */
1312                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1313                         &session->priv->ctx,
1314                         &event_recorder_priv->parent.filter_bytecode_runtime_head,
1315                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1316
1317                 /* TODO: merge event context. */
1318         }
1319 end:
1320         return 0;
1321 }
1322
1323 /*
1324  * Called at library load: connect the probe on all enablers matching
1325  * this event.
1326  * Called with session mutex held.
1327  */
1328 int lttng_fix_pending_events(void)
1329 {
1330         struct lttng_ust_session_private *session_priv;
1331
1332         cds_list_for_each_entry(session_priv, &sessions, node) {
1333                 /*
1334                  * New probes have appeared, we need to re-sync all
1335                  * enablers.
1336                  */
1337                 lttng_session_unsync_enablers(session_priv->pub);
1338                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1339         }
1340         return 0;
1341 }
1342
1343 int lttng_fix_pending_event_notifiers(void)
1344 {
1345         struct lttng_event_notifier_group *event_notifier_group;
1346
1347         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1348                 /*
1349                  * New probes have appeared, we need to re-sync all
1350                  * enablers.
1351                  */
1352                 lttng_event_notifier_group_unsync_enablers(event_notifier_group);
1353                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1354         }
1355         return 0;
1356 }
1357
1358 /*
1359  * For each session of the owner thread, execute pending statedump.
1360  * Only dump state for the sessions owned by the caller thread, because
1361  * we don't keep ust_lock across the entire iteration.
1362  */
1363 void lttng_handle_pending_statedump(void *owner)
1364 {
1365         struct lttng_ust_session_private *session_priv;
1366
1367         /* Execute state dump */
1368         do_lttng_ust_statedump(owner);
1369
1370         /* Clear pending state dump */
1371         if (ust_lock()) {
1372                 goto end;
1373         }
1374         cds_list_for_each_entry(session_priv, &sessions, node) {
1375                 if (session_priv->owner != owner)
1376                         continue;
1377                 if (!session_priv->statedump_pending)
1378                         continue;
1379                 session_priv->statedump_pending = 0;
1380         }
1381 end:
1382         ust_unlock();
1383         return;
1384 }
1385
1386 static
1387 void _lttng_event_destroy(struct lttng_ust_event_common *event)
1388 {
1389         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1390
1391         lttng_free_event_filter_runtime(event);
1392         /* Free event enabler refs */
1393         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1394                         &event->priv->enablers_ref_head, node)
1395                 free(enabler_ref);
1396
1397         switch (event->type) {
1398         case LTTNG_UST_EVENT_TYPE_RECORDER:
1399         {
1400                 struct lttng_ust_event_recorder *event_recorder = event->child;
1401
1402                 /* Remove from event list. */
1403                 cds_list_del(&event_recorder->priv->node);
1404                 /* Remove from event hash table. */
1405                 cds_hlist_del(&event_recorder->priv->hlist);
1406
1407                 lttng_destroy_context(event_recorder->priv->ctx);
1408                 free(event_recorder->parent);
1409                 free(event_recorder->priv);
1410                 free(event_recorder);
1411                 break;
1412         }
1413         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1414         {
1415                 struct lttng_ust_event_notifier *event_notifier = event->child;
1416
1417                 /* Remove from event list. */
1418                 cds_list_del(&event_notifier->priv->node);
1419                 /* Remove from event hash table. */
1420                 cds_hlist_del(&event_notifier->priv->hlist);
1421
1422                 free(event_notifier->priv);
1423                 free(event_notifier->parent);
1424                 free(event_notifier);
1425                 break;
1426         }
1427         default:
1428                 abort();
1429         }
1430 }
1431
1432 static
1433 void _lttng_enum_destroy(struct lttng_enum *_enum)
1434 {
1435         cds_list_del(&_enum->node);
1436         cds_hlist_del(&_enum->hlist);
1437         free(_enum);
1438 }
1439
1440 void lttng_ust_abi_events_exit(void)
1441 {
1442         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1443
1444         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1445                 lttng_session_destroy(session_priv->pub);
1446 }
1447
1448 /*
1449  * Enabler management.
1450  */
1451 struct lttng_event_enabler *lttng_event_enabler_create(
1452                 enum lttng_enabler_format_type format_type,
1453                 struct lttng_ust_abi_event *event_param,
1454                 struct lttng_ust_channel_buffer *chan)
1455 {
1456         struct lttng_event_enabler *event_enabler;
1457
1458         event_enabler = zmalloc(sizeof(*event_enabler));
1459         if (!event_enabler)
1460                 return NULL;
1461         event_enabler->base.format_type = format_type;
1462         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1463         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1464         memcpy(&event_enabler->base.event_param, event_param,
1465                 sizeof(event_enabler->base.event_param));
1466         event_enabler->chan = chan;
1467         /* ctx left NULL */
1468         event_enabler->base.enabled = 0;
1469         cds_list_add(&event_enabler->node, &event_enabler->chan->parent->session->priv->unsync_enablers_head);
1470         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1471
1472         return event_enabler;
1473 }
1474
1475 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1476                 struct lttng_event_notifier_group *event_notifier_group,
1477                 enum lttng_enabler_format_type format_type,
1478                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1479 {
1480         struct lttng_event_notifier_enabler *event_notifier_enabler;
1481
1482         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1483         if (!event_notifier_enabler)
1484                 return NULL;
1485         event_notifier_enabler->base.format_type = format_type;
1486         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1487         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1488         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1489
1490         event_notifier_enabler->user_token = event_notifier_param->event.token;
1491         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1492         event_notifier_enabler->num_captures = 0;
1493
1494         memcpy(&event_notifier_enabler->base.event_param.name,
1495                 event_notifier_param->event.name,
1496                 sizeof(event_notifier_enabler->base.event_param.name));
1497         event_notifier_enabler->base.event_param.instrumentation =
1498                 event_notifier_param->event.instrumentation;
1499         event_notifier_enabler->base.event_param.loglevel =
1500                 event_notifier_param->event.loglevel;
1501         event_notifier_enabler->base.event_param.loglevel_type =
1502                 event_notifier_param->event.loglevel_type;
1503
1504         event_notifier_enabler->base.enabled = 0;
1505         event_notifier_enabler->group = event_notifier_group;
1506
1507         cds_list_add(&event_notifier_enabler->node,
1508                         &event_notifier_group->unsync_enablers_head);
1509
1510         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1511
1512         return event_notifier_enabler;
1513 }
1514
1515 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1516 {
1517         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1518         lttng_event_enabler_unsync(event_enabler);
1519         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1520
1521         return 0;
1522 }
1523
1524 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1525 {
1526         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1527         lttng_event_enabler_unsync(event_enabler);
1528         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1529
1530         return 0;
1531 }
1532
1533 static
1534 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1535                 struct lttng_ust_bytecode_node **bytecode)
1536 {
1537         (*bytecode)->enabler = enabler;
1538         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1539         /* Take ownership of bytecode */
1540         *bytecode = NULL;
1541 }
1542
1543 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1544                 struct lttng_ust_bytecode_node **bytecode)
1545 {
1546         _lttng_enabler_attach_filter_bytecode(
1547                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1548         lttng_event_enabler_unsync(event_enabler);
1549         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1550         return 0;
1551 }
1552
1553 static
1554 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1555                 struct lttng_ust_excluder_node **excluder)
1556 {
1557         (*excluder)->enabler = enabler;
1558         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1559         /* Take ownership of excluder */
1560         *excluder = NULL;
1561 }
1562
1563 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1564                 struct lttng_ust_excluder_node **excluder)
1565 {
1566         _lttng_enabler_attach_exclusion(
1567                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1568         lttng_event_enabler_unsync(event_enabler);
1569         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1570         return 0;
1571 }
1572
1573 int lttng_event_notifier_enabler_enable(
1574                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1575 {
1576         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1577         lttng_event_notifier_enabler_unsync(event_notifier_enabler);
1578         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1579
1580         return 0;
1581 }
1582
1583 int lttng_event_notifier_enabler_disable(
1584                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1585 {
1586         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1587         lttng_event_notifier_enabler_unsync(event_notifier_enabler);
1588         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1589
1590         return 0;
1591 }
1592
1593 int lttng_event_notifier_enabler_attach_filter_bytecode(
1594                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1595                 struct lttng_ust_bytecode_node **bytecode)
1596 {
1597         _lttng_enabler_attach_filter_bytecode(
1598                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1599                 bytecode);
1600         lttng_event_notifier_enabler_unsync(event_notifier_enabler);
1601         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1602         return 0;
1603 }
1604
1605 int lttng_event_notifier_enabler_attach_capture_bytecode(
1606                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1607                 struct lttng_ust_bytecode_node **bytecode)
1608 {
1609         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1610                         event_notifier_enabler);
1611         cds_list_add_tail(&(*bytecode)->node,
1612                         &event_notifier_enabler->capture_bytecode_head);
1613         /* Take ownership of bytecode */
1614         *bytecode = NULL;
1615         event_notifier_enabler->num_captures++;
1616         lttng_event_notifier_enabler_unsync(event_notifier_enabler);
1617         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1618         return 0;
1619 }
1620
1621 int lttng_event_notifier_enabler_attach_exclusion(
1622                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1623                 struct lttng_ust_excluder_node **excluder)
1624 {
1625         _lttng_enabler_attach_exclusion(
1626                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1627                 excluder);
1628         lttng_event_notifier_enabler_unsync(event_notifier_enabler);
1629         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1630         return 0;
1631 }
1632
1633 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1634                 union lttng_ust_abi_args *uargs,
1635                 struct lttng_ust_ctx **ctx, struct lttng_ust_session *session)
1636 {
1637         /*
1638          * We cannot attach a context after trace has been started for a
1639          * session because the metadata does not allow expressing this
1640          * information outside of the original channel scope.
1641          */
1642         if (session->priv->been_active)
1643                 return -EPERM;
1644
1645         switch (context_param->ctx) {
1646         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1647                 return lttng_add_pthread_id_to_ctx(ctx);
1648         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1649         {
1650                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1651
1652                 perf_ctx_param = &context_param->u.perf_counter;
1653                 return lttng_add_perf_counter_to_ctx(
1654                         perf_ctx_param->type,
1655                         perf_ctx_param->config,
1656                         perf_ctx_param->name,
1657                         ctx);
1658         }
1659         case LTTNG_UST_ABI_CONTEXT_VTID:
1660                 return lttng_add_vtid_to_ctx(ctx);
1661         case LTTNG_UST_ABI_CONTEXT_VPID:
1662                 return lttng_add_vpid_to_ctx(ctx);
1663         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1664                 return lttng_add_procname_to_ctx(ctx);
1665         case LTTNG_UST_ABI_CONTEXT_IP:
1666                 return lttng_add_ip_to_ctx(ctx);
1667         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1668                 return lttng_add_cpu_id_to_ctx(ctx);
1669         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1670                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1671                         ctx);
1672         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1673                 return lttng_add_cgroup_ns_to_ctx(ctx);
1674         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1675                 return lttng_add_ipc_ns_to_ctx(ctx);
1676         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1677                 return lttng_add_mnt_ns_to_ctx(ctx);
1678         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1679                 return lttng_add_net_ns_to_ctx(ctx);
1680         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1681                 return lttng_add_pid_ns_to_ctx(ctx);
1682         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1683                 return lttng_add_time_ns_to_ctx(ctx);
1684         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1685                 return lttng_add_user_ns_to_ctx(ctx);
1686         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1687                 return lttng_add_uts_ns_to_ctx(ctx);
1688         case LTTNG_UST_ABI_CONTEXT_VUID:
1689                 return lttng_add_vuid_to_ctx(ctx);
1690         case LTTNG_UST_ABI_CONTEXT_VEUID:
1691                 return lttng_add_veuid_to_ctx(ctx);
1692         case LTTNG_UST_ABI_CONTEXT_VSUID:
1693                 return lttng_add_vsuid_to_ctx(ctx);
1694         case LTTNG_UST_ABI_CONTEXT_VGID:
1695                 return lttng_add_vgid_to_ctx(ctx);
1696         case LTTNG_UST_ABI_CONTEXT_VEGID:
1697                 return lttng_add_vegid_to_ctx(ctx);
1698         case LTTNG_UST_ABI_CONTEXT_VSGID:
1699                 return lttng_add_vsgid_to_ctx(ctx);
1700         default:
1701                 return -EINVAL;
1702         }
1703 }
1704
1705 int lttng_event_enabler_attach_context(
1706                 struct lttng_event_enabler *enabler __attribute__((unused)),
1707                 struct lttng_ust_abi_context *context_param __attribute__((unused)))
1708 {
1709         return -ENOSYS;
1710 }
1711
1712 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1713 {
1714         if (!event_enabler) {
1715                 return;
1716         }
1717         cds_list_del(&event_enabler->node);
1718
1719         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1720
1721         lttng_destroy_context(event_enabler->ctx);
1722         free(event_enabler);
1723 }
1724
1725 /*
1726  * lttng_session_sync_event_enablers should be called just before starting a
1727  * session.
1728  */
1729 static
1730 void lttng_session_sync_event_enablers(struct lttng_ust_session *session)
1731 {
1732         struct lttng_event_enabler *event_enabler;
1733         struct lttng_ust_event_recorder_private *event_recorder_priv;
1734         struct cds_list_head iter_list;
1735
1736         /*
1737          * lttng_event_enabler_ref_event_recorders can cause lazy probes
1738          * to add items to the unsync_enablers_head list. Iterate on a
1739          * local copy of that list until it is stable (empty).
1740          */
1741         do {
1742                 CDS_INIT_LIST_HEAD(&iter_list);
1743                 cds_list_splice(&session->priv->unsync_enablers_head, &iter_list);
1744                 CDS_INIT_LIST_HEAD(&session->priv->unsync_enablers_head);
1745                 cds_list_for_each_entry(event_enabler, &iter_list, node)
1746                         lttng_event_enabler_ref_event_recorders(event_enabler);
1747                 cds_list_splice(&iter_list, &session->priv->sync_enablers_head);
1748         } while (!cds_list_empty(&session->priv->unsync_enablers_head));
1749
1750         /*
1751          * For each event, if at least one of its enablers is enabled,
1752          * and its channel and session transient states are enabled, we
1753          * enable the event, else we disable it.
1754          */
1755         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1756                 struct lttng_enabler_ref *enabler_ref;
1757                 struct lttng_ust_bytecode_runtime *runtime;
1758                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1759                 int nr_filters = 0;
1760
1761                 /* Enable events */
1762                 cds_list_for_each_entry(enabler_ref,
1763                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1764                         if (enabler_ref->ref->enabled) {
1765                                 enabled = 1;
1766                                 break;
1767                         }
1768                 }
1769                 /*
1770                  * Enabled state is based on union of enablers, with
1771                  * intesection of session and channel transient enable
1772                  * states.
1773                  */
1774                 enabled = enabled && session->priv->tstate && event_recorder_priv->pub->chan->priv->parent.tstate;
1775
1776                 CMM_STORE_SHARED(event_recorder_priv->pub->parent->enabled, enabled);
1777                 /*
1778                  * Sync tracepoint registration with event enabled
1779                  * state.
1780                  */
1781                 if (enabled) {
1782                         if (!event_recorder_priv->parent.registered)
1783                                 register_event(event_recorder_priv->parent.pub);
1784                 } else {
1785                         if (event_recorder_priv->parent.registered)
1786                                 unregister_event(event_recorder_priv->parent.pub);
1787                 }
1788
1789                 /* Check if has enablers without bytecode enabled */
1790                 cds_list_for_each_entry(enabler_ref,
1791                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1792                         if (enabler_ref->ref->enabled
1793                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1794                                 has_enablers_without_filter_bytecode = 1;
1795                                 break;
1796                         }
1797                 }
1798                 event_recorder_priv->parent.has_enablers_without_filter_bytecode =
1799                         has_enablers_without_filter_bytecode;
1800
1801                 /* Enable filters */
1802                 cds_list_for_each_entry(runtime,
1803                                 &event_recorder_priv->parent.filter_bytecode_runtime_head, node) {
1804                         lttng_bytecode_sync_state(runtime);
1805                         nr_filters++;
1806                 }
1807                 CMM_STORE_SHARED(event_recorder_priv->parent.pub->eval_filter,
1808                         !(has_enablers_without_filter_bytecode || !nr_filters));
1809         }
1810         lttng_ust_tp_probe_prune_release_queue();
1811 }
1812
1813 static
1814 void lttng_create_event_notifier_if_missing(
1815                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1816 {
1817         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1818         struct lttng_ust_registered_probe *reg_probe;
1819         struct cds_list_head *probe_list;
1820         int i;
1821
1822         probe_list = lttng_get_probe_list_head();
1823
1824         cds_list_for_each_entry(reg_probe, probe_list, head) {
1825                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1826
1827                 for (i = 0; i < probe_desc->nr_events; i++) {
1828                         int ret;
1829                         bool found = false;
1830                         const struct lttng_ust_event_desc *desc;
1831                         struct lttng_ust_event_notifier_private *event_notifier_priv;
1832                         struct cds_hlist_head *head;
1833                         struct cds_hlist_node *node;
1834
1835                         desc = probe_desc->event_desc[i];
1836
1837                         if (!lttng_desc_match_enabler(desc,
1838                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1839                                 continue;
1840
1841                         /*
1842                          * Given the current event_notifier group, get the bucket that
1843                          * the target event_notifier would be if it was already
1844                          * created.
1845                          */
1846                         head = borrow_hash_table_bucket(
1847                                 event_notifier_group->event_notifiers_ht.table,
1848                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1849
1850                         cds_hlist_for_each_entry(event_notifier_priv, node, head, hlist) {
1851                                 /*
1852                                  * Check if event_notifier already exists by checking
1853                                  * if the event_notifier and enabler share the same
1854                                  * description and id.
1855                                  */
1856                                 if (event_notifier_priv->parent.desc == desc &&
1857                                                 event_notifier_priv->parent.user_token == event_notifier_enabler->user_token) {
1858                                         found = true;
1859                                         break;
1860                                 }
1861                         }
1862
1863                         if (found)
1864                                 continue;
1865
1866                         /*
1867                          * We need to create a event_notifier for this event probe.
1868                          */
1869                         ret = lttng_event_notifier_create(desc,
1870                                 event_notifier_enabler->user_token,
1871                                 event_notifier_enabler->error_counter_index,
1872                                 event_notifier_group);
1873                         if (ret) {
1874                                 DBG("Unable to create event_notifier \"%s:%s\", error %d\n",
1875                                         probe_desc->provider_name,
1876                                         probe_desc->event_desc[i]->event_name, ret);
1877                         }
1878                 }
1879         }
1880 }
1881
1882 /*
1883  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1884  */
1885 static
1886 int lttng_event_notifier_enabler_ref_event_notifiers(
1887                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1888 {
1889         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1890         struct lttng_ust_event_notifier_private *event_notifier_priv;
1891
1892          /*
1893           * Only try to create event_notifiers for enablers that are enabled, the user
1894           * might still be attaching filter or exclusion to the
1895           * event_notifier_enabler.
1896           */
1897         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1898                 goto end;
1899
1900         /* First, ensure that probe event_notifiers are created for this enabler. */
1901         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1902
1903         /* Link the created event_notifier with its associated enabler. */
1904         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1905                 struct lttng_enabler_ref *enabler_ref;
1906
1907                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier_priv->pub))
1908                         continue;
1909
1910                 enabler_ref = lttng_enabler_ref(&event_notifier_priv->parent.enablers_ref_head,
1911                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1912                 if (!enabler_ref) {
1913                         /*
1914                          * If no backward ref, create it.
1915                          * Add backward ref from event_notifier to enabler.
1916                          */
1917                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1918                         if (!enabler_ref)
1919                                 return -ENOMEM;
1920
1921                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1922                                 event_notifier_enabler);
1923                         cds_list_add(&enabler_ref->node,
1924                                 &event_notifier_priv->parent.enablers_ref_head);
1925                 }
1926
1927                 /*
1928                  * Link filter bytecodes if not linked yet.
1929                  */
1930                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1931                         &event_notifier_group->ctx,
1932                         &event_notifier_priv->parent.filter_bytecode_runtime_head,
1933                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1934
1935                 /*
1936                  * Link capture bytecodes if not linked yet.
1937                  */
1938                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1939                         &event_notifier_group->ctx, &event_notifier_priv->capture_bytecode_runtime_head,
1940                         &event_notifier_enabler->capture_bytecode_head);
1941
1942                 event_notifier_priv->num_captures = event_notifier_enabler->num_captures;
1943         }
1944 end:
1945         return 0;
1946 }
1947
1948 static
1949 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1950 {
1951         struct lttng_event_notifier_enabler *event_notifier_enabler;
1952         struct lttng_ust_event_notifier_private *event_notifier_priv;
1953         struct cds_list_head iter_list;
1954
1955         /*
1956          * lttng_event_notifier_enabler_ref_event_notifiers can cause
1957          * lazy probes to add items to the unsync_enablers_head list.
1958          * Iterate on a local copy of that list until it is stable
1959          * (empty).
1960          */
1961         do {
1962                 CDS_INIT_LIST_HEAD(&iter_list);
1963                 cds_list_splice(&event_notifier_group->unsync_enablers_head, &iter_list);
1964                 CDS_INIT_LIST_HEAD(&event_notifier_group->unsync_enablers_head);
1965                 cds_list_for_each_entry(event_notifier_enabler, &iter_list, node)
1966                         lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1967                 cds_list_splice(&iter_list, &event_notifier_group->sync_enablers_head);
1968         } while (!cds_list_empty(&event_notifier_group->unsync_enablers_head));
1969
1970         /*
1971          * For each event_notifier, if at least one of its enablers is enabled,
1972          * we enable the event_notifier, else we disable it.
1973          */
1974         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1975                 struct lttng_enabler_ref *enabler_ref;
1976                 struct lttng_ust_bytecode_runtime *runtime;
1977                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1978                 int nr_filters = 0, nr_captures = 0;
1979
1980                 /* Enable event_notifiers */
1981                 cds_list_for_each_entry(enabler_ref,
1982                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1983                         if (enabler_ref->ref->enabled) {
1984                                 enabled = 1;
1985                                 break;
1986                         }
1987                 }
1988
1989                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1990                 /*
1991                  * Sync tracepoint registration with event_notifier enabled
1992                  * state.
1993                  */
1994                 if (enabled) {
1995                         if (!event_notifier_priv->parent.registered)
1996                                 register_event(event_notifier_priv->parent.pub);
1997                 } else {
1998                         if (event_notifier_priv->parent.registered)
1999                                 unregister_event(event_notifier_priv->parent.pub);
2000                 }
2001
2002                 /* Check if has enablers without bytecode enabled */
2003                 cds_list_for_each_entry(enabler_ref,
2004                                 &event_notifier_priv->parent.enablers_ref_head, node) {
2005                         if (enabler_ref->ref->enabled
2006                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
2007                                 has_enablers_without_filter_bytecode = 1;
2008                                 break;
2009                         }
2010                 }
2011                 event_notifier_priv->parent.has_enablers_without_filter_bytecode =
2012                         has_enablers_without_filter_bytecode;
2013
2014                 /* Enable filters */
2015                 cds_list_for_each_entry(runtime,
2016                                 &event_notifier_priv->parent.filter_bytecode_runtime_head, node) {
2017                         lttng_bytecode_sync_state(runtime);
2018                         nr_filters++;
2019                 }
2020                 CMM_STORE_SHARED(event_notifier_priv->parent.pub->eval_filter,
2021                         !(has_enablers_without_filter_bytecode || !nr_filters));
2022
2023                 /* Enable captures. */
2024                 cds_list_for_each_entry(runtime,
2025                                 &event_notifier_priv->capture_bytecode_runtime_head, node) {
2026                         lttng_bytecode_sync_state(runtime);
2027                         nr_captures++;
2028                 }
2029                 CMM_STORE_SHARED(event_notifier_priv->pub->eval_capture,
2030                                 !!nr_captures);
2031         }
2032         lttng_ust_tp_probe_prune_release_queue();
2033 }
2034
2035 /*
2036  * Apply enablers to session events, adding events to session if need
2037  * be. It is required after each modification applied to an active
2038  * session, and right before session "start".
2039  * "lazy" sync means we only sync if required.
2040  */
2041 static
2042 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session)
2043 {
2044         /* We can skip if session is not active */
2045         if (!session->active)
2046                 return;
2047         lttng_session_sync_event_enablers(session);
2048 }
2049
2050 /*
2051  * Update all sessions with the given app context.
2052  * Called with ust lock held.
2053  * This is invoked when an application context gets loaded/unloaded. It
2054  * ensures the context callbacks are in sync with the application
2055  * context (either app context callbacks, or dummy callbacks).
2056  */
2057 void lttng_ust_context_set_session_provider(const char *name,
2058                 size_t (*get_size)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2059                         size_t offset),
2060                 void (*record)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2061                         struct lttng_ust_ring_buffer_ctx *ctx,
2062                         struct lttng_ust_channel_buffer *chan),
2063                 void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2064                         struct lttng_ust_ctx_value *value))
2065 {
2066         struct lttng_ust_session_private *session_priv;
2067
2068         cds_list_for_each_entry(session_priv, &sessions, node) {
2069                 struct lttng_ust_channel_buffer_private *chan;
2070                 struct lttng_ust_event_recorder_private *event_recorder_priv;
2071                 int ret;
2072
2073                 ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
2074                                 name, get_size, record, get_value);
2075                 if (ret)
2076                         abort();
2077                 cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
2078                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
2079                                         name, get_size, record, get_value);
2080                         if (ret)
2081                                 abort();
2082                 }
2083                 cds_list_for_each_entry(event_recorder_priv, &session_priv->events_head, node) {
2084                         ret = lttng_ust_context_set_provider_rcu(&event_recorder_priv->ctx,
2085                                         name, get_size, record, get_value);
2086                         if (ret)
2087                                 abort();
2088                 }
2089         }
2090 }
2091
2092 /*
2093  * Update all event_notifier groups with the given app context.
2094  * Called with ust lock held.
2095  * This is invoked when an application context gets loaded/unloaded. It
2096  * ensures the context callbacks are in sync with the application
2097  * context (either app context callbacks, or dummy callbacks).
2098  */
2099 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
2100                 size_t (*get_size)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2101                         size_t offset),
2102                 void (*record)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2103                         struct lttng_ust_ring_buffer_ctx *ctx,
2104                         struct lttng_ust_channel_buffer *chan),
2105                 void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2106                         struct lttng_ust_ctx_value *value))
2107 {
2108         struct lttng_event_notifier_group *event_notifier_group;
2109
2110         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2111                 int ret;
2112
2113                 ret = lttng_ust_context_set_provider_rcu(
2114                                 &event_notifier_group->ctx,
2115                                 name, get_size, record, get_value);
2116                 if (ret)
2117                         abort();
2118         }
2119 }
2120
2121 int lttng_ust_session_uuid_validate(struct lttng_ust_session *session,
2122                 unsigned char *uuid)
2123 {
2124         if (!session)
2125                 return 0;
2126         /* Compare UUID with session. */
2127         if (session->priv->uuid_set) {
2128                 if (memcmp(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN)) {
2129                         return -1;
2130                 }
2131         } else {
2132                 memcpy(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
2133                 session->priv->uuid_set = true;
2134         }
2135         return 0;
2136
2137 }