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