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_recorder_destroy(struct lttng_ust_event_recorder *event_recorder);
  74 static void _lttng_event_notifier_destroy(
  75                 struct lttng_ust_event_notifier *event_notifier);
  76 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  77
  78 static
  79 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  80 static
  81 void lttng_session_sync_event_enablers(struct lttng_session *session);
  82 static
  83 void lttng_event_notifier_group_sync_enablers(
  84                 struct lttng_event_notifier_group *event_notifier_group);
  85 static
  86 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  87
  88 /*
  89  * Called with ust lock held.
  90  */
  91 int lttng_session_active(void)
  92 {
  93         struct lttng_ust_session_private *iter;
  94
  95         cds_list_for_each_entry(iter, &sessions, node) {
  96                 if (iter->pub->active)
  97                         return 1;
  98         }
  99         return 0;
 100 }
 101
 102 static
 103 int lttng_loglevel_match(int loglevel,
 104                 unsigned int has_loglevel,
 105                 enum lttng_ust_abi_loglevel_type req_type,
 106                 int req_loglevel)
 107 {
 108         if (!has_loglevel)
 109                 loglevel = TRACE_DEFAULT;
 110         switch (req_type) {
 111         case LTTNG_UST_ABI_LOGLEVEL_RANGE:
 112                 if (loglevel <= req_loglevel
 113                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 114                         return 1;
 115                 else
 116                         return 0;
 117         case LTTNG_UST_ABI_LOGLEVEL_SINGLE:
 118                 if (loglevel == req_loglevel
 119                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 120                         return 1;
 121                 else
 122                         return 0;
 123         case LTTNG_UST_ABI_LOGLEVEL_ALL:
 124         default:
 125                 if (loglevel <= TRACE_DEBUG)
 126                         return 1;
 127                 else
 128                         return 0;
 129         }
 130 }
 131
 132 struct lttng_session *lttng_session_create(void)
 133 {
 134         struct lttng_session *session;
 135         struct lttng_ust_session_private *session_priv;
 136         int i;
 137
 138         session = zmalloc(sizeof(struct lttng_session));
 139         if (!session)
 140                 return NULL;
 141         session->struct_size = sizeof(struct lttng_session);
 142         session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
 143         if (!session_priv) {
 144                 free(session);
 145                 return NULL;
 146         }
 147         session->priv = session_priv;
 148         session_priv->pub = session;
 149         if (lttng_context_init_all(&session->priv->ctx)) {
 150                 free(session_priv);
 151                 free(session);
 152                 return NULL;
 153         }
 154         CDS_INIT_LIST_HEAD(&session->priv->chan_head);
 155         CDS_INIT_LIST_HEAD(&session->priv->events_head);
 156         CDS_INIT_LIST_HEAD(&session->priv->enums_head);
 157         CDS_INIT_LIST_HEAD(&session->priv->enablers_head);
 158         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 159                 CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 160         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 161                 CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
 162         cds_list_add(&session->priv->node, &sessions);
 163         return session;
 164 }
 165
 166 struct lttng_counter *lttng_ust_counter_create(
 167                 const char *counter_transport_name,
 168                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 169 {
 170         struct lttng_counter_transport *counter_transport = NULL;
 171         struct lttng_counter *counter = NULL;
 172
 173         counter_transport = lttng_counter_transport_find(counter_transport_name);
 174         if (!counter_transport)
 175                 goto notransport;
 176         counter = zmalloc(sizeof(struct lttng_counter));
 177         if (!counter)
 178                 goto nomem;
 179
 180         counter->ops = &counter_transport->ops;
 181         counter->transport = counter_transport;
 182
 183         counter->counter = counter->ops->counter_create(
 184                         number_dimensions, dimensions, 0,
 185                         -1, 0, NULL, false);
 186         if (!counter->counter) {
 187                 goto create_error;
 188         }
 189
 190         return counter;
 191
 192 create_error:
 193         free(counter);
 194 nomem:
 195 notransport:
 196         return NULL;
 197 }
 198
 199 static
 200 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 201 {
 202         counter->ops->counter_destroy(counter->counter);
 203         free(counter);
 204 }
 205
 206 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 207 {
 208         struct lttng_event_notifier_group *event_notifier_group;
 209         int i;
 210
 211         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 212         if (!event_notifier_group)
 213                 return NULL;
 214
 215         /* Add all contexts. */
 216         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 217                 free(event_notifier_group);
 218                 return NULL;
 219         }
 220
 221         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 222         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 223         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 224                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 225
 226         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 227
 228         return event_notifier_group;
 229 }
 230
 231 /*
 232  * Only used internally at session destruction.
 233  */
 234 static
 235 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 236 {
 237         struct channel *chan;
 238         struct lttng_ust_shm_handle *handle;
 239
 240         cds_list_del(&lttng_chan->node);
 241         lttng_destroy_context(lttng_chan->ctx);
 242         chan = lttng_chan->chan;
 243         handle = lttng_chan->handle;
 244         /*
 245          * note: lttng_chan is private data contained within handle. It
 246          * will be freed along with the handle.
 247          */
 248         channel_destroy(chan, handle, 0);
 249 }
 250
 251 static
 252 void register_event_recorder(struct lttng_ust_event_recorder *event_recorder)
 253 {
 254         int ret;
 255         const struct lttng_event_desc *desc;
 256
 257         assert(event_recorder->parent->priv->registered == 0);
 258         desc = event_recorder->parent->priv->desc;
 259         ret = __tracepoint_probe_register_queue_release(desc->name,
 260                         desc->probe_callback,
 261                         event_recorder, desc->signature);
 262         WARN_ON_ONCE(ret);
 263         if (!ret)
 264                 event_recorder->parent->priv->registered = 1;
 265 }
 266
 267 static
 268 void register_event_notifier(struct lttng_ust_event_notifier *event_notifier)
 269 {
 270         int ret;
 271         const struct lttng_event_desc *desc;
 272
 273         assert(event_notifier->parent->priv->registered == 0);
 274         desc = event_notifier->parent->priv->desc;
 275         ret = __tracepoint_probe_register_queue_release(desc->name,
 276                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 277         WARN_ON_ONCE(ret);
 278         if (!ret)
 279                 event_notifier->parent->priv->registered = 1;
 280 }
 281
 282 static
 283 void unregister_event_recorder(struct lttng_ust_event_recorder *event_recorder)
 284 {
 285         int ret;
 286         const struct lttng_event_desc *desc;
 287
 288         assert(event_recorder->parent->priv->registered == 1);
 289         desc = event_recorder->parent->priv->desc;
 290         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 291                         desc->probe_callback,
 292                         event_recorder);
 293         WARN_ON_ONCE(ret);
 294         if (!ret)
 295                 event_recorder->parent->priv->registered = 0;
 296 }
 297
 298 static
 299 void unregister_event_notifier(struct lttng_ust_event_notifier *event_notifier)
 300 {
 301         int ret;
 302         const struct lttng_event_desc *desc;
 303
 304         assert(event_notifier->parent->priv->registered == 1);
 305         desc = event_notifier->parent->priv->desc;
 306         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 307                 desc->u.ext.event_notifier_callback, event_notifier);
 308         WARN_ON_ONCE(ret);
 309         if (!ret)
 310                 event_notifier->parent->priv->registered = 0;
 311 }
 312
 313 /*
 314  * Only used internally at session destruction.
 315  */
 316 static
 317 void _lttng_event_recorder_unregister(struct lttng_ust_event_recorder *event_recorder)
 318 {
 319         if (event_recorder->parent->priv->registered)
 320                 unregister_event_recorder(event_recorder);
 321 }
 322
 323 /*
 324  * Only used internally at session destruction.
 325  */
 326 static
 327 void _lttng_event_notifier_unregister(struct lttng_ust_event_notifier *event_notifier)
 328 {
 329         if (event_notifier->parent->priv->registered)
 330                 unregister_event_notifier(event_notifier);
 331 }
 332
 333 void lttng_session_destroy(struct lttng_session *session)
 334 {
 335         struct lttng_channel *chan, *tmpchan;
 336         struct lttng_ust_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
 337         struct lttng_enum *_enum, *tmp_enum;
 338         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 339
 340         CMM_ACCESS_ONCE(session->active) = 0;
 341         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
 342                 _lttng_event_recorder_unregister(event_recorder_priv->pub);
 343         }
 344         lttng_ust_urcu_synchronize_rcu();       /* Wait for in-flight events to complete */
 345         __tracepoint_probe_prune_release_queue();
 346         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 347                         &session->priv->enablers_head, node)
 348                 lttng_event_enabler_destroy(event_enabler);
 349         cds_list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv,
 350                         &session->priv->events_head, node)
 351                 _lttng_event_recorder_destroy(event_recorder_priv->pub);
 352         cds_list_for_each_entry_safe(_enum, tmp_enum,
 353                         &session->priv->enums_head, node)
 354                 _lttng_enum_destroy(_enum);
 355         cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 356                 _lttng_channel_unmap(chan);
 357         cds_list_del(&session->priv->node);
 358         lttng_destroy_context(session->priv->ctx);
 359         free(session->priv);
 360         free(session);
 361 }
 362
 363 void lttng_event_notifier_group_destroy(
 364                 struct lttng_event_notifier_group *event_notifier_group)
 365 {
 366         int close_ret;
 367         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 368         struct lttng_ust_event_notifier_private *notifier_priv, *tmpnotifier_priv;
 369
 370         if (!event_notifier_group) {
 371                 return;
 372         }
 373
 374         cds_list_for_each_entry(notifier_priv,
 375                         &event_notifier_group->event_notifiers_head, node)
 376                 _lttng_event_notifier_unregister(notifier_priv->pub);
 377
 378         lttng_ust_urcu_synchronize_rcu();
 379
 380         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 381                         &event_notifier_group->enablers_head, node)
 382                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 383
 384         cds_list_for_each_entry_safe(notifier_priv, tmpnotifier_priv,
 385                         &event_notifier_group->event_notifiers_head, node)
 386                 _lttng_event_notifier_destroy(notifier_priv->pub);
 387
 388         if (event_notifier_group->error_counter)
 389                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 390
 391         /* Close the notification fd to the listener of event_notifiers. */
 392
 393         lttng_ust_lock_fd_tracker();
 394         close_ret = close(event_notifier_group->notification_fd);
 395         if (!close_ret) {
 396                 lttng_ust_delete_fd_from_tracker(
 397                                 event_notifier_group->notification_fd);
 398         } else {
 399                 PERROR("close");
 400                 abort();
 401         }
 402         lttng_ust_unlock_fd_tracker();
 403
 404         cds_list_del(&event_notifier_group->node);
 405
 406         free(event_notifier_group);
 407 }
 408
 409 static
 410 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 411 {
 412         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 413         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 414
 415         if (!enabler) {
 416                 return;
 417         }
 418
 419         /* Destroy filter bytecode */
 420         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 421                         &enabler->filter_bytecode_head, node) {
 422                 free(filter_node);
 423         }
 424
 425         /* Destroy excluders */
 426         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 427                         &enabler->excluder_head, node) {
 428                 free(excluder_node);
 429         }
 430 }
 431
 432  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 433 {
 434         if (!event_notifier_enabler) {
 435                 return;
 436         }
 437
 438         cds_list_del(&event_notifier_enabler->node);
 439
 440         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 441
 442         free(event_notifier_enabler);
 443 }
 444
 445 static
 446 int lttng_enum_create(const struct lttng_enum_desc *desc,
 447                 struct lttng_session *session)
 448 {
 449         const char *enum_name = desc->name;
 450         struct lttng_enum *_enum;
 451         struct cds_hlist_head *head;
 452         int ret = 0;
 453         size_t name_len = strlen(enum_name);
 454         uint32_t hash;
 455         int notify_socket;
 456
 457         /* Check if this enum is already registered for this session. */
 458         hash = jhash(enum_name, name_len, 0);
 459         head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 460
 461         _enum = lttng_ust_enum_get_from_desc(session, desc);
 462         if (_enum) {
 463                 ret = -EEXIST;
 464                 goto exist;
 465         }
 466
 467         notify_socket = lttng_get_notify_socket(session->priv->owner);
 468         if (notify_socket < 0) {
 469                 ret = notify_socket;
 470                 goto socket_error;
 471         }
 472
 473         _enum = zmalloc(sizeof(*_enum));
 474         if (!_enum) {
 475                 ret = -ENOMEM;
 476                 goto cache_error;
 477         }
 478         _enum->session = session;
 479         _enum->desc = desc;
 480
 481         ret = ustcomm_register_enum(notify_socket,
 482                 session->priv->objd,
 483                 enum_name,
 484                 desc->nr_entries,
 485                 desc->entries,
 486                 &_enum->id);
 487         if (ret < 0) {
 488                 DBG("Error (%d) registering enumeration to sessiond", ret);
 489                 goto sessiond_register_error;
 490         }
 491         cds_list_add(&_enum->node, &session->priv->enums_head);
 492         cds_hlist_add_head(&_enum->hlist, head);
 493         return 0;
 494
 495 sessiond_register_error:
 496         free(_enum);
 497 cache_error:
 498 socket_error:
 499 exist:
 500         return ret;
 501 }
 502
 503 static
 504 int lttng_create_enum_check(const struct lttng_type *type,
 505                 struct lttng_session *session)
 506 {
 507         switch (type->atype) {
 508         case atype_enum_nestable:
 509         {
 510                 const struct lttng_enum_desc *enum_desc;
 511                 int ret;
 512
 513                 enum_desc = type->u.enum_nestable.desc;
 514                 ret = lttng_enum_create(enum_desc, session);
 515                 if (ret && ret != -EEXIST) {
 516                         DBG("Unable to create enum error: (%d)", ret);
 517                         return ret;
 518                 }
 519                 break;
 520         }
 521         case atype_dynamic:
 522         {
 523                 const struct lttng_event_field *tag_field_generic;
 524                 const struct lttng_enum_desc *enum_desc;
 525                 int ret;
 526
 527                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 528                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 529                 ret = lttng_enum_create(enum_desc, session);
 530                 if (ret && ret != -EEXIST) {
 531                         DBG("Unable to create enum error: (%d)", ret);
 532                         return ret;
 533                 }
 534                 break;
 535         }
 536         default:
 537                 /* TODO: nested types when they become supported. */
 538                 break;
 539         }
 540         return 0;
 541 }
 542
 543 static
 544 int lttng_create_all_event_enums(size_t nr_fields,
 545                 const struct lttng_event_field *event_fields,
 546                 struct lttng_session *session)
 547 {
 548         size_t i;
 549         int ret;
 550
 551         /* For each field, ensure enum is part of the session. */
 552         for (i = 0; i < nr_fields; i++) {
 553                 const struct lttng_type *type = &event_fields[i].type;
 554
 555                 ret = lttng_create_enum_check(type, session);
 556                 if (ret)
 557                         return ret;
 558         }
 559         return 0;
 560 }
 561
 562 static
 563 int lttng_create_all_ctx_enums(size_t nr_fields,
 564                 const struct lttng_ctx_field *ctx_fields,
 565                 struct lttng_session *session)
 566 {
 567         size_t i;
 568         int ret;
 569
 570         /* For each field, ensure enum is part of the session. */
 571         for (i = 0; i < nr_fields; i++) {
 572                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 573
 574                 ret = lttng_create_enum_check(type, session);
 575                 if (ret)
 576                         return ret;
 577         }
 578         return 0;
 579 }
 580
 581 /*
 582  * Ensure that a state-dump will be performed for this session at the end
 583  * of the current handle_message().
 584  */
 585 int lttng_session_statedump(struct lttng_session *session)
 586 {
 587         session->priv->statedump_pending = 1;
 588         lttng_ust_sockinfo_session_enabled(session->priv->owner);
 589         return 0;
 590 }
 591
 592 int lttng_session_enable(struct lttng_session *session)
 593 {
 594         int ret = 0;
 595         struct lttng_channel *chan;
 596         int notify_socket;
 597
 598         if (session->active) {
 599                 ret = -EBUSY;
 600                 goto end;
 601         }
 602
 603         notify_socket = lttng_get_notify_socket(session->priv->owner);
 604         if (notify_socket < 0)
 605                 return notify_socket;
 606
 607         /* Set transient enabler state to "enabled" */
 608         session->priv->tstate = 1;
 609
 610         /* We need to sync enablers with session before activation. */
 611         lttng_session_sync_event_enablers(session);
 612
 613         /*
 614          * Snapshot the number of events per channel to know the type of header
 615          * we need to use.
 616          */
 617         cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 618                 const struct lttng_ctx *ctx;
 619                 const struct lttng_ctx_field *fields = NULL;
 620                 size_t nr_fields = 0;
 621                 uint32_t chan_id;
 622
 623                 /* don't change it if session stop/restart */
 624                 if (chan->header_type)
 625                         continue;
 626                 ctx = chan->ctx;
 627                 if (ctx) {
 628                         nr_fields = ctx->nr_fields;
 629                         fields = ctx->fields;
 630                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 631                                 session);
 632                         if (ret < 0) {
 633                                 DBG("Error (%d) adding enum to session", ret);
 634                                 return ret;
 635                         }
 636                 }
 637                 ret = ustcomm_register_channel(notify_socket,
 638                         session,
 639                         session->priv->objd,
 640                         chan->objd,
 641                         nr_fields,
 642                         fields,
 643                         &chan_id,
 644                         &chan->header_type);
 645                 if (ret) {
 646                         DBG("Error (%d) registering channel to sessiond", ret);
 647                         return ret;
 648                 }
 649                 if (chan_id != chan->id) {
 650                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 651                                 chan_id, chan->id);
 652                         return -EINVAL;
 653                 }
 654         }
 655
 656         /* Set atomically the state to "active" */
 657         CMM_ACCESS_ONCE(session->active) = 1;
 658         CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 659
 660         ret = lttng_session_statedump(session);
 661         if (ret)
 662                 return ret;
 663 end:
 664         return ret;
 665 }
 666
 667 int lttng_session_disable(struct lttng_session *session)
 668 {
 669         int ret = 0;
 670
 671         if (!session->active) {
 672                 ret = -EBUSY;
 673                 goto end;
 674         }
 675         /* Set atomically the state to "inactive" */
 676         CMM_ACCESS_ONCE(session->active) = 0;
 677
 678         /* Set transient enabler state to "disabled" */
 679         session->priv->tstate = 0;
 680         lttng_session_sync_event_enablers(session);
 681 end:
 682         return ret;
 683 }
 684
 685 int lttng_channel_enable(struct lttng_channel *channel)
 686 {
 687         int ret = 0;
 688
 689         if (channel->enabled) {
 690                 ret = -EBUSY;
 691                 goto end;
 692         }
 693         /* Set transient enabler state to "enabled" */
 694         channel->tstate = 1;
 695         lttng_session_sync_event_enablers(channel->session);
 696         /* Set atomically the state to "enabled" */
 697         CMM_ACCESS_ONCE(channel->enabled) = 1;
 698 end:
 699         return ret;
 700 }
 701
 702 int lttng_channel_disable(struct lttng_channel *channel)
 703 {
 704         int ret = 0;
 705
 706         if (!channel->enabled) {
 707                 ret = -EBUSY;
 708                 goto end;
 709         }
 710         /* Set atomically the state to "disabled" */
 711         CMM_ACCESS_ONCE(channel->enabled) = 0;
 712         /* Set transient enabler state to "enabled" */
 713         channel->tstate = 0;
 714         lttng_session_sync_event_enablers(channel->session);
 715 end:
 716         return ret;
 717 }
 718
 719 static inline
 720 struct cds_hlist_head *borrow_hash_table_bucket(
 721                 struct cds_hlist_head *hash_table,
 722                 unsigned int hash_table_size,
 723                 const struct lttng_event_desc *desc)
 724 {
 725         const char *event_name;
 726         size_t name_len;
 727         uint32_t hash;
 728
 729         event_name = desc->name;
 730         name_len = strlen(event_name);
 731
 732         hash = jhash(event_name, name_len, 0);
 733         return &hash_table[hash & (hash_table_size - 1)];
 734 }
 735
 736 /*
 737  * Supports event creation while tracing session is active.
 738  */
 739 static
 740 int lttng_event_recorder_create(const struct lttng_event_desc *desc,
 741                 struct lttng_channel *chan)
 742 {
 743         struct lttng_ust_event_recorder *event_recorder;
 744         struct lttng_ust_event_recorder_private *event_recorder_priv;
 745         struct lttng_session *session = chan->session;
 746         struct cds_hlist_head *head;
 747         int ret = 0;
 748         int notify_socket, loglevel;
 749         const char *uri;
 750
 751         head = borrow_hash_table_bucket(chan->session->priv->events_ht.table,
 752                 LTTNG_UST_EVENT_HT_SIZE, desc);
 753
 754         notify_socket = lttng_get_notify_socket(session->priv->owner);
 755         if (notify_socket < 0) {
 756                 ret = notify_socket;
 757                 goto socket_error;
 758         }
 759
 760         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 761                         session);
 762         if (ret < 0) {
 763                 DBG("Error (%d) adding enum to session", ret);
 764                 goto create_enum_error;
 765         }
 766
 767         /*
 768          * Check if loglevel match. Refuse to connect event if not.
 769          */
 770         event_recorder = zmalloc(sizeof(struct lttng_ust_event_recorder));
 771         if (!event_recorder) {
 772                 ret = -ENOMEM;
 773                 goto cache_error;
 774         }
 775         event_recorder->struct_size = sizeof(struct lttng_ust_event_recorder);
 776
 777         event_recorder->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 778         if (!event_recorder->parent) {
 779                 ret = -ENOMEM;
 780                 goto parent_error;
 781         }
 782         event_recorder->parent->struct_size = sizeof(struct lttng_ust_event_common);
 783
 784         event_recorder_priv = zmalloc(sizeof(struct lttng_ust_event_recorder_private));
 785         if (!event_recorder_priv) {
 786                 ret = -ENOMEM;
 787                 goto priv_error;
 788         }
 789         event_recorder->priv = event_recorder_priv;
 790         event_recorder_priv->pub = event_recorder;
 791         event_recorder->parent->priv = &event_recorder_priv->parent;
 792         event_recorder_priv->parent.pub = event_recorder->parent;
 793
 794         event_recorder->chan = chan;
 795
 796         /* Event will be enabled by enabler sync. */
 797         event_recorder->parent->enabled = 0;
 798         event_recorder->parent->priv->registered = 0;
 799         CDS_INIT_LIST_HEAD(&event_recorder->parent->filter_bytecode_runtime_head);
 800         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 801         event_recorder->parent->priv->desc = desc;
 802
 803         if (desc->loglevel)
 804                 loglevel = *(*event_recorder->parent->priv->desc->loglevel);
 805         else
 806                 loglevel = TRACE_DEFAULT;
 807         if (desc->u.ext.model_emf_uri)
 808                 uri = *(desc->u.ext.model_emf_uri);
 809         else
 810                 uri = NULL;
 811
 812         /* Fetch event ID from sessiond */
 813         ret = ustcomm_register_event(notify_socket,
 814                 session,
 815                 session->priv->objd,
 816                 chan->objd,
 817                 desc->name,
 818                 loglevel,
 819                 desc->signature,
 820                 desc->nr_fields,
 821                 desc->fields,
 822                 uri,
 823                 &event_recorder->id);
 824         if (ret < 0) {
 825                 DBG("Error (%d) registering event to sessiond", ret);
 826                 goto sessiond_register_error;
 827         }
 828
 829         cds_list_add(&event_recorder->priv->node, &chan->session->priv->events_head);
 830         cds_hlist_add_head(&event_recorder->priv->hlist, head);
 831         return 0;
 832
 833 sessiond_register_error:
 834         free(event_recorder_priv);
 835 priv_error:
 836         free(event_recorder->parent);
 837 parent_error:
 838         free(event_recorder);
 839 cache_error:
 840 create_enum_error:
 841 socket_error:
 842         return ret;
 843 }
 844
 845 static
 846 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 847                 uint64_t token, uint64_t error_counter_index,
 848                 struct lttng_event_notifier_group *event_notifier_group)
 849 {
 850         struct lttng_ust_event_notifier *event_notifier;
 851         struct lttng_ust_event_notifier_private *event_notifier_priv;
 852         struct cds_hlist_head *head;
 853         int ret = 0;
 854
 855         /*
 856          * Get the hashtable bucket the created lttng_event_notifier object
 857          * should be inserted.
 858          */
 859         head = borrow_hash_table_bucket(
 860                 event_notifier_group->event_notifiers_ht.table,
 861                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 862
 863         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 864         if (!event_notifier) {
 865                 ret = -ENOMEM;
 866                 goto error;
 867         }
 868         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 869
 870         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 871         if (!event_notifier->parent) {
 872                 ret = -ENOMEM;
 873                 goto parent_error;
 874         }
 875         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 876
 877         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 878         if (!event_notifier_priv) {
 879                 ret = -ENOMEM;
 880                 goto priv_error;
 881         }
 882         event_notifier->priv = event_notifier_priv;
 883         event_notifier_priv->pub = event_notifier;
 884         event_notifier->parent->priv = &event_notifier_priv->parent;
 885         event_notifier_priv->parent.pub = event_notifier->parent;
 886
 887         event_notifier_priv->group = event_notifier_group;
 888         event_notifier_priv->parent.user_token = token;
 889         event_notifier_priv->error_counter_index = error_counter_index;
 890
 891         /* Event notifier will be enabled by enabler sync. */
 892         event_notifier->parent->enabled = 0;
 893         event_notifier_priv->parent.registered = 0;
 894
 895         CDS_INIT_LIST_HEAD(&event_notifier->parent->filter_bytecode_runtime_head);
 896         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 897         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 898         event_notifier_priv->parent.desc = desc;
 899         event_notifier->notification_send = lttng_event_notifier_notification_send;
 900
 901         cds_list_add(&event_notifier_priv->node,
 902                         &event_notifier_group->event_notifiers_head);
 903         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 904
 905         return 0;
 906
 907 priv_error:
 908         free(event_notifier->parent);
 909 parent_error:
 910         free(event_notifier);
 911 error:
 912         return ret;
 913 }
 914
 915 static
 916 void _lttng_event_notifier_destroy(struct lttng_ust_event_notifier *event_notifier)
 917 {
 918         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 919
 920         /* Remove from event_notifier list. */
 921         cds_list_del(&event_notifier->priv->node);
 922         /* Remove from event_notifier hash table. */
 923         cds_hlist_del(&event_notifier->priv->hlist);
 924
 925         lttng_free_event_filter_runtime(event_notifier->parent);
 926
 927         /* Free event_notifier enabler refs */
 928         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 929                         &event_notifier->priv->parent.enablers_ref_head, node)
 930                 free(enabler_ref);
 931         free(event_notifier->priv);
 932         free(event_notifier->parent);
 933         free(event_notifier);
 934 }
 935
 936 static
 937 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 938                 struct lttng_enabler *enabler)
 939 {
 940         int loglevel = 0;
 941         unsigned int has_loglevel = 0;
 942
 943         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 944         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 945                         desc->name, SIZE_MAX))
 946                 return 0;
 947         if (desc->loglevel) {
 948                 loglevel = *(*desc->loglevel);
 949                 has_loglevel = 1;
 950         }
 951         if (!lttng_loglevel_match(loglevel,
 952                         has_loglevel,
 953                         enabler->event_param.loglevel_type,
 954                         enabler->event_param.loglevel))
 955                 return 0;
 956         return 1;
 957 }
 958
 959 static
 960 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 961                 struct lttng_enabler *enabler)
 962 {
 963         int loglevel = 0;
 964         unsigned int has_loglevel = 0;
 965
 966         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 967         if (strcmp(desc->name, enabler->event_param.name))
 968                 return 0;
 969         if (desc->loglevel) {
 970                 loglevel = *(*desc->loglevel);
 971                 has_loglevel = 1;
 972         }
 973         if (!lttng_loglevel_match(loglevel,
 974                         has_loglevel,
 975                         enabler->event_param.loglevel_type,
 976                         enabler->event_param.loglevel))
 977                 return 0;
 978         return 1;
 979 }
 980
 981 static
 982 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 983                 struct lttng_enabler *enabler)
 984 {
 985         switch (enabler->format_type) {
 986         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 987         {
 988                 struct lttng_ust_excluder_node *excluder;
 989
 990                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 991                         return 0;
 992                 }
 993
 994                 /*
 995                  * If the matching event matches with an excluder,
 996                  * return 'does not match'
 997                  */
 998                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 999                         int count;
1000
1001                         for (count = 0; count < excluder->excluder.count; count++) {
1002                                 int len;
1003                                 char *excluder_name;
1004
1005                                 excluder_name = (char *) (excluder->excluder.names)
1006                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
1007                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1008                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
1009                                         return 0;
1010                         }
1011                 }
1012                 return 1;
1013         }
1014         case LTTNG_ENABLER_FORMAT_EVENT:
1015                 return lttng_desc_match_event_enabler(desc, enabler);
1016         default:
1017                 return -EINVAL;
1018         }
1019 }
1020
1021 static
1022 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
1023                 struct lttng_ust_event_recorder *event_recorder)
1024 {
1025         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
1026                         lttng_event_enabler_as_enabler(event_enabler))
1027                         && event_recorder->chan == event_enabler->chan)
1028                 return 1;
1029         else
1030                 return 0;
1031 }
1032
1033 static
1034 int lttng_event_notifier_enabler_match_event_notifier(
1035                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1036                 struct lttng_ust_event_notifier *event_notifier)
1037 {
1038         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
1039                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1040
1041         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
1042                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
1043                 return 1;
1044         else
1045                 return 0;
1046 }
1047
1048 static
1049 struct lttng_enabler_ref *lttng_enabler_ref(
1050                 struct cds_list_head *enabler_ref_list,
1051                 struct lttng_enabler *enabler)
1052 {
1053         struct lttng_enabler_ref *enabler_ref;
1054
1055         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1056                 if (enabler_ref->ref == enabler)
1057                         return enabler_ref;
1058         }
1059         return NULL;
1060 }
1061
1062 /*
1063  * Create struct lttng_event if it is missing and present in the list of
1064  * tracepoint probes.
1065  */
1066 static
1067 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1068 {
1069         struct lttng_session *session = event_enabler->chan->session;
1070         struct lttng_probe_desc *probe_desc;
1071         const struct lttng_event_desc *desc;
1072         struct lttng_ust_event_recorder_private *event_recorder_priv;
1073         int i;
1074         struct cds_list_head *probe_list;
1075
1076         probe_list = lttng_get_probe_list_head();
1077         /*
1078          * For each probe event, if we find that a probe event matches
1079          * our enabler, create an associated lttng_event if not
1080          * already present.
1081          */
1082         cds_list_for_each_entry(probe_desc, probe_list, head) {
1083                 for (i = 0; i < probe_desc->nr_events; i++) {
1084                         int ret;
1085                         bool found = false;
1086                         struct cds_hlist_head *head;
1087                         struct cds_hlist_node *node;
1088
1089                         desc = probe_desc->event_desc[i];
1090                         if (!lttng_desc_match_enabler(desc,
1091                                         lttng_event_enabler_as_enabler(event_enabler)))
1092                                 continue;
1093
1094                         head = borrow_hash_table_bucket(
1095                                 session->priv->events_ht.table,
1096                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1097
1098                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1099                                 if (event_recorder_priv->parent.desc == desc
1100                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1101                                         found = true;
1102                                         break;
1103                                 }
1104                         }
1105                         if (found)
1106                                 continue;
1107
1108                         /*
1109                          * We need to create an event for this
1110                          * event probe.
1111                          */
1112                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1113                                         event_enabler->chan);
1114                         if (ret) {
1115                                 DBG("Unable to create event %s, error %d\n",
1116                                         probe_desc->event_desc[i]->name, ret);
1117                         }
1118                 }
1119         }
1120 }
1121
1122 static
1123 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1124                 void (*event_func)(struct lttng_session *session,
1125                         struct lttng_ust_event_recorder *event_recorder),
1126                 void (*event_notifier_func)(struct lttng_ust_event_notifier *event_notifier))
1127 {
1128         struct cds_hlist_node *node, *tmp_node;
1129         struct cds_list_head *sessionsp;
1130         unsigned int i;
1131
1132         /* Get handle on list of sessions. */
1133         sessionsp = lttng_get_sessions();
1134
1135         /*
1136          * Iterate over all events in the probe provider descriptions and
1137          * sessions to queue the unregistration of the events.
1138          */
1139         for (i = 0; i < provider_desc->nr_events; i++) {
1140                 const struct lttng_event_desc *event_desc;
1141                 struct lttng_event_notifier_group *event_notifier_group;
1142                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1143                 struct lttng_ust_session_private *session_priv;
1144                 struct cds_hlist_head *head;
1145                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1146
1147                 event_desc = provider_desc->event_desc[i];
1148
1149                 /*
1150                  * Iterate over all session to find the current event
1151                  * description.
1152                  */
1153                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1154                         /*
1155                          * Get the list of events in the hashtable bucket and
1156                          * iterate to find the event matching this descriptor.
1157                          */
1158                         head = borrow_hash_table_bucket(
1159                                 session_priv->events_ht.table,
1160                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1161
1162                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1163                                 if (event_desc == event_recorder_priv->parent.desc) {
1164                                         event_func(session_priv->pub, event_recorder_priv->pub);
1165                                         break;
1166                                 }
1167                         }
1168                 }
1169
1170                 /*
1171                  * Iterate over all event_notifier groups to find the current event
1172                  * description.
1173                  */
1174                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1175                         /*
1176                          * Get the list of event_notifiers in the hashtable bucket and
1177                          * iterate to find the event_notifier matching this
1178                          * descriptor.
1179                          */
1180                         head = borrow_hash_table_bucket(
1181                                 event_notifier_group->event_notifiers_ht.table,
1182                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1183
1184                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1185                                 if (event_desc == event_notifier_priv->parent.desc) {
1186                                         event_notifier_func(event_notifier_priv->pub);
1187                                         break;
1188                                 }
1189                         }
1190                 }
1191         }
1192 }
1193
1194 static
1195 void _unregister_event_recorder(struct lttng_session *session,
1196                 struct lttng_ust_event_recorder *event_recorder)
1197 {
1198         _lttng_event_recorder_unregister(event_recorder);
1199 }
1200
1201 static
1202 void _event_enum_destroy(struct lttng_session *session,
1203                 struct lttng_ust_event_recorder *event_recorder)
1204 {
1205         unsigned int i;
1206
1207         /* Destroy enums of the current event. */
1208         for (i = 0; i < event_recorder->parent->priv->desc->nr_fields; i++) {
1209                 const struct lttng_enum_desc *enum_desc;
1210                 const struct lttng_event_field *field;
1211                 struct lttng_enum *curr_enum;
1212
1213                 field = &(event_recorder->parent->priv->desc->fields[i]);
1214                 switch (field->type.atype) {
1215                 case atype_enum_nestable:
1216                         enum_desc = field->type.u.enum_nestable.desc;
1217                         break;
1218                 default:
1219                         continue;
1220                 }
1221
1222                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1223                 if (curr_enum) {
1224                         _lttng_enum_destroy(curr_enum);
1225                 }
1226         }
1227
1228         /* Destroy event. */
1229         _lttng_event_recorder_destroy(event_recorder);
1230 }
1231
1232 /*
1233  * Iterate over all the UST sessions to unregister and destroy all probes from
1234  * the probe provider descriptor received as argument. Must me called with the
1235  * ust_lock held.
1236  */
1237 void lttng_probe_provider_unregister_events(
1238                 struct lttng_probe_desc *provider_desc)
1239 {
1240         /*
1241          * Iterate over all events in the probe provider descriptions and sessions
1242          * to queue the unregistration of the events.
1243          */
1244         probe_provider_event_for_each(provider_desc, _unregister_event_recorder,
1245                 _lttng_event_notifier_unregister);
1246
1247         /* Wait for grace period. */
1248         lttng_ust_urcu_synchronize_rcu();
1249         /* Prune the unregistration queue. */
1250         __tracepoint_probe_prune_release_queue();
1251
1252         /*
1253          * It is now safe to destroy the events and remove them from the event list
1254          * and hashtables.
1255          */
1256         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1257                 _lttng_event_notifier_destroy);
1258 }
1259
1260 /*
1261  * Create events associated with an event enabler (if not already present),
1262  * and add backward reference from the event to the enabler.
1263  */
1264 static
1265 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1266 {
1267         struct lttng_session *session = event_enabler->chan->session;
1268         struct lttng_ust_event_recorder_private *event_recorder_priv;
1269
1270         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1271                 goto end;
1272
1273         /* First ensure that probe events are created for this enabler. */
1274         lttng_create_event_if_missing(event_enabler);
1275
1276         /* For each event matching enabler in session event list. */
1277         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1278                 struct lttng_enabler_ref *enabler_ref;
1279
1280                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1281                         continue;
1282
1283                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1284                         lttng_event_enabler_as_enabler(event_enabler));
1285                 if (!enabler_ref) {
1286                         /*
1287                          * If no backward ref, create it.
1288                          * Add backward ref from event to enabler.
1289                          */
1290                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1291                         if (!enabler_ref)
1292                                 return -ENOMEM;
1293                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1294                                 event_enabler);
1295                         cds_list_add(&enabler_ref->node,
1296                                 &event_recorder_priv->parent.enablers_ref_head);
1297                 }
1298
1299                 /*
1300                  * Link filter bytecodes if not linked yet.
1301                  */
1302                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1303                         &session->priv->ctx,
1304                         &event_recorder_priv->pub->parent->filter_bytecode_runtime_head,
1305                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1306
1307                 /* TODO: merge event context. */
1308         }
1309 end:
1310         return 0;
1311 }
1312
1313 /*
1314  * Called at library load: connect the probe on all enablers matching
1315  * this event.
1316  * Called with session mutex held.
1317  */
1318 int lttng_fix_pending_events(void)
1319 {
1320         struct lttng_ust_session_private *session_priv;
1321
1322         cds_list_for_each_entry(session_priv, &sessions, node) {
1323                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1324         }
1325         return 0;
1326 }
1327
1328 int lttng_fix_pending_event_notifiers(void)
1329 {
1330         struct lttng_event_notifier_group *event_notifier_group;
1331
1332         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1333                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1334         }
1335         return 0;
1336 }
1337
1338 /*
1339  * For each session of the owner thread, execute pending statedump.
1340  * Only dump state for the sessions owned by the caller thread, because
1341  * we don't keep ust_lock across the entire iteration.
1342  */
1343 void lttng_handle_pending_statedump(void *owner)
1344 {
1345         struct lttng_ust_session_private *session_priv;
1346
1347         /* Execute state dump */
1348         do_lttng_ust_statedump(owner);
1349
1350         /* Clear pending state dump */
1351         if (ust_lock()) {
1352                 goto end;
1353         }
1354         cds_list_for_each_entry(session_priv, &sessions, node) {
1355                 if (session_priv->owner != owner)
1356                         continue;
1357                 if (!session_priv->statedump_pending)
1358                         continue;
1359                 session_priv->statedump_pending = 0;
1360         }
1361 end:
1362         ust_unlock();
1363         return;
1364 }
1365
1366 /*
1367  * Only used internally at session destruction.
1368  */
1369 static
1370 void _lttng_event_recorder_destroy(struct lttng_ust_event_recorder *event_recorder)
1371 {
1372         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1373
1374         /* Remove from event list. */
1375         cds_list_del(&event_recorder->priv->node);
1376         /* Remove from event hash table. */
1377         cds_hlist_del(&event_recorder->priv->hlist);
1378
1379         lttng_destroy_context(event_recorder->ctx);
1380         lttng_free_event_filter_runtime(event_recorder->parent);
1381         /* Free event enabler refs */
1382         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1383                         &event_recorder->parent->priv->enablers_ref_head, node)
1384                 free(enabler_ref);
1385         free(event_recorder->priv);
1386         free(event_recorder->parent);
1387         free(event_recorder);
1388 }
1389
1390 static
1391 void _lttng_enum_destroy(struct lttng_enum *_enum)
1392 {
1393         cds_list_del(&_enum->node);
1394         cds_hlist_del(&_enum->hlist);
1395         free(_enum);
1396 }
1397
1398 void lttng_ust_abi_events_exit(void)
1399 {
1400         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1401
1402         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1403                 lttng_session_destroy(session_priv->pub);
1404 }
1405
1406 /*
1407  * Enabler management.
1408  */
1409 struct lttng_event_enabler *lttng_event_enabler_create(
1410                 enum lttng_enabler_format_type format_type,
1411                 struct lttng_ust_abi_event *event_param,
1412                 struct lttng_channel *chan)
1413 {
1414         struct lttng_event_enabler *event_enabler;
1415
1416         event_enabler = zmalloc(sizeof(*event_enabler));
1417         if (!event_enabler)
1418                 return NULL;
1419         event_enabler->base.format_type = format_type;
1420         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1421         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1422         memcpy(&event_enabler->base.event_param, event_param,
1423                 sizeof(event_enabler->base.event_param));
1424         event_enabler->chan = chan;
1425         /* ctx left NULL */
1426         event_enabler->base.enabled = 0;
1427         cds_list_add(&event_enabler->node, &event_enabler->chan->session->priv->enablers_head);
1428         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1429
1430         return event_enabler;
1431 }
1432
1433 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1434                 struct lttng_event_notifier_group *event_notifier_group,
1435                 enum lttng_enabler_format_type format_type,
1436                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1437 {
1438         struct lttng_event_notifier_enabler *event_notifier_enabler;
1439
1440         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1441         if (!event_notifier_enabler)
1442                 return NULL;
1443         event_notifier_enabler->base.format_type = format_type;
1444         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1445         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1446         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1447
1448         event_notifier_enabler->user_token = event_notifier_param->event.token;
1449         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1450         event_notifier_enabler->num_captures = 0;
1451
1452         memcpy(&event_notifier_enabler->base.event_param.name,
1453                 event_notifier_param->event.name,
1454                 sizeof(event_notifier_enabler->base.event_param.name));
1455         event_notifier_enabler->base.event_param.instrumentation =
1456                 event_notifier_param->event.instrumentation;
1457         event_notifier_enabler->base.event_param.loglevel =
1458                 event_notifier_param->event.loglevel;
1459         event_notifier_enabler->base.event_param.loglevel_type =
1460                 event_notifier_param->event.loglevel_type;
1461
1462         event_notifier_enabler->base.enabled = 0;
1463         event_notifier_enabler->group = event_notifier_group;
1464
1465         cds_list_add(&event_notifier_enabler->node,
1466                         &event_notifier_group->enablers_head);
1467
1468         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1469
1470         return event_notifier_enabler;
1471 }
1472
1473 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1474 {
1475         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1476         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1477
1478         return 0;
1479 }
1480
1481 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1482 {
1483         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1484         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1485
1486         return 0;
1487 }
1488
1489 static
1490 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1491                 struct lttng_ust_bytecode_node **bytecode)
1492 {
1493         (*bytecode)->enabler = enabler;
1494         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1495         /* Take ownership of bytecode */
1496         *bytecode = NULL;
1497 }
1498
1499 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1500                 struct lttng_ust_bytecode_node **bytecode)
1501 {
1502         _lttng_enabler_attach_filter_bytecode(
1503                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1504
1505         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1506         return 0;
1507 }
1508
1509 static
1510 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1511                 struct lttng_ust_excluder_node **excluder)
1512 {
1513         (*excluder)->enabler = enabler;
1514         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1515         /* Take ownership of excluder */
1516         *excluder = NULL;
1517 }
1518
1519 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1520                 struct lttng_ust_excluder_node **excluder)
1521 {
1522         _lttng_enabler_attach_exclusion(
1523                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1524
1525         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1526         return 0;
1527 }
1528
1529 int lttng_event_notifier_enabler_enable(
1530                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1531 {
1532         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1533         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1534
1535         return 0;
1536 }
1537
1538 int lttng_event_notifier_enabler_disable(
1539                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1540 {
1541         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1542         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1543
1544         return 0;
1545 }
1546
1547 int lttng_event_notifier_enabler_attach_filter_bytecode(
1548                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1549                 struct lttng_ust_bytecode_node **bytecode)
1550 {
1551         _lttng_enabler_attach_filter_bytecode(
1552                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1553                 bytecode);
1554
1555         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1556         return 0;
1557 }
1558
1559 int lttng_event_notifier_enabler_attach_capture_bytecode(
1560                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1561                 struct lttng_ust_bytecode_node **bytecode)
1562 {
1563         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1564                         event_notifier_enabler);
1565         cds_list_add_tail(&(*bytecode)->node,
1566                         &event_notifier_enabler->capture_bytecode_head);
1567         /* Take ownership of bytecode */
1568         *bytecode = NULL;
1569         event_notifier_enabler->num_captures++;
1570
1571         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1572         return 0;
1573 }
1574
1575 int lttng_event_notifier_enabler_attach_exclusion(
1576                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1577                 struct lttng_ust_excluder_node **excluder)
1578 {
1579         _lttng_enabler_attach_exclusion(
1580                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1581                 excluder);
1582
1583         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1584         return 0;
1585 }
1586
1587 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1588                 union lttng_ust_abi_args *uargs,
1589                 struct lttng_ctx **ctx, struct lttng_session *session)
1590 {
1591         /*
1592          * We cannot attach a context after trace has been started for a
1593          * session because the metadata does not allow expressing this
1594          * information outside of the original channel scope.
1595          */
1596         if (session->priv->been_active)
1597                 return -EPERM;
1598
1599         switch (context_param->ctx) {
1600         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1601                 return lttng_add_pthread_id_to_ctx(ctx);
1602         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1603         {
1604                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1605
1606                 perf_ctx_param = &context_param->u.perf_counter;
1607                 return lttng_add_perf_counter_to_ctx(
1608                         perf_ctx_param->type,
1609                         perf_ctx_param->config,
1610                         perf_ctx_param->name,
1611                         ctx);
1612         }
1613         case LTTNG_UST_ABI_CONTEXT_VTID:
1614                 return lttng_add_vtid_to_ctx(ctx);
1615         case LTTNG_UST_ABI_CONTEXT_VPID:
1616                 return lttng_add_vpid_to_ctx(ctx);
1617         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1618                 return lttng_add_procname_to_ctx(ctx);
1619         case LTTNG_UST_ABI_CONTEXT_IP:
1620                 return lttng_add_ip_to_ctx(ctx);
1621         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1622                 return lttng_add_cpu_id_to_ctx(ctx);
1623         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1624                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1625                         ctx);
1626         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1627                 return lttng_add_cgroup_ns_to_ctx(ctx);
1628         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1629                 return lttng_add_ipc_ns_to_ctx(ctx);
1630         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1631                 return lttng_add_mnt_ns_to_ctx(ctx);
1632         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1633                 return lttng_add_net_ns_to_ctx(ctx);
1634         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1635                 return lttng_add_pid_ns_to_ctx(ctx);
1636         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1637                 return lttng_add_time_ns_to_ctx(ctx);
1638         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1639                 return lttng_add_user_ns_to_ctx(ctx);
1640         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1641                 return lttng_add_uts_ns_to_ctx(ctx);
1642         case LTTNG_UST_ABI_CONTEXT_VUID:
1643                 return lttng_add_vuid_to_ctx(ctx);
1644         case LTTNG_UST_ABI_CONTEXT_VEUID:
1645                 return lttng_add_veuid_to_ctx(ctx);
1646         case LTTNG_UST_ABI_CONTEXT_VSUID:
1647                 return lttng_add_vsuid_to_ctx(ctx);
1648         case LTTNG_UST_ABI_CONTEXT_VGID:
1649                 return lttng_add_vgid_to_ctx(ctx);
1650         case LTTNG_UST_ABI_CONTEXT_VEGID:
1651                 return lttng_add_vegid_to_ctx(ctx);
1652         case LTTNG_UST_ABI_CONTEXT_VSGID:
1653                 return lttng_add_vsgid_to_ctx(ctx);
1654         default:
1655                 return -EINVAL;
1656         }
1657 }
1658
1659 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1660                 struct lttng_ust_abi_context *context_param)
1661 {
1662         return -ENOSYS;
1663 }
1664
1665 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1666 {
1667         if (!event_enabler) {
1668                 return;
1669         }
1670         cds_list_del(&event_enabler->node);
1671
1672         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1673
1674         lttng_destroy_context(event_enabler->ctx);
1675         free(event_enabler);
1676 }
1677
1678 /*
1679  * lttng_session_sync_event_enablers should be called just before starting a
1680  * session.
1681  */
1682 static
1683 void lttng_session_sync_event_enablers(struct lttng_session *session)
1684 {
1685         struct lttng_event_enabler *event_enabler;
1686         struct lttng_ust_event_recorder_private *event_recorder_priv;
1687
1688         cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
1689                 lttng_event_enabler_ref_events(event_enabler);
1690         /*
1691          * For each event, if at least one of its enablers is enabled,
1692          * and its channel and session transient states are enabled, we
1693          * enable the event, else we disable it.
1694          */
1695         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1696                 struct lttng_enabler_ref *enabler_ref;
1697                 struct lttng_bytecode_runtime *runtime;
1698                 int enabled = 0, has_enablers_without_bytecode = 0;
1699
1700                 /* Enable events */
1701                 cds_list_for_each_entry(enabler_ref,
1702                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1703                         if (enabler_ref->ref->enabled) {
1704                                 enabled = 1;
1705                                 break;
1706                         }
1707                 }
1708                 /*
1709                  * Enabled state is based on union of enablers, with
1710                  * intesection of session and channel transient enable
1711                  * states.
1712                  */
1713                 enabled = enabled && session->priv->tstate && event_recorder_priv->pub->chan->tstate;
1714
1715                 CMM_STORE_SHARED(event_recorder_priv->pub->parent->enabled, enabled);
1716                 /*
1717                  * Sync tracepoint registration with event enabled
1718                  * state.
1719                  */
1720                 if (enabled) {
1721                         if (!event_recorder_priv->parent.registered)
1722                                 register_event_recorder(event_recorder_priv->pub);
1723                 } else {
1724                         if (event_recorder_priv->parent.registered)
1725                                 unregister_event_recorder(event_recorder_priv->pub);
1726                 }
1727
1728                 /* Check if has enablers without bytecode enabled */
1729                 cds_list_for_each_entry(enabler_ref,
1730                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1731                         if (enabler_ref->ref->enabled
1732                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1733                                 has_enablers_without_bytecode = 1;
1734                                 break;
1735                         }
1736                 }
1737                 event_recorder_priv->pub->parent->has_enablers_without_bytecode =
1738                         has_enablers_without_bytecode;
1739
1740                 /* Enable filters */
1741                 cds_list_for_each_entry(runtime,
1742                                 &event_recorder_priv->pub->parent->filter_bytecode_runtime_head, node) {
1743                         lttng_bytecode_filter_sync_state(runtime);
1744                 }
1745         }
1746         __tracepoint_probe_prune_release_queue();
1747 }
1748
1749 /* Support for event notifier is introduced by probe provider major version 2. */
1750 static
1751 bool lttng_ust_probe_supports_event_notifier(struct lttng_probe_desc *probe_desc)
1752 {
1753         return probe_desc->major >= 2;
1754 }
1755
1756 static
1757 void lttng_create_event_notifier_if_missing(
1758                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1759 {
1760         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1761         struct lttng_probe_desc *probe_desc;
1762         struct cds_list_head *probe_list;
1763         int i;
1764
1765         probe_list = lttng_get_probe_list_head();
1766
1767         cds_list_for_each_entry(probe_desc, probe_list, head) {
1768                 for (i = 0; i < probe_desc->nr_events; i++) {
1769                         int ret;
1770                         bool found = false;
1771                         const struct lttng_event_desc *desc;
1772                         struct lttng_ust_event_notifier_private *event_notifier_priv;
1773                         struct cds_hlist_head *head;
1774                         struct cds_hlist_node *node;
1775
1776                         desc = probe_desc->event_desc[i];
1777
1778                         if (!lttng_desc_match_enabler(desc,
1779                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1780                                 continue;
1781
1782                         /*
1783                          * Given the current event_notifier group, get the bucket that
1784                          * the target event_notifier would be if it was already
1785                          * created.
1786                          */
1787                         head = borrow_hash_table_bucket(
1788                                 event_notifier_group->event_notifiers_ht.table,
1789                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1790
1791                         cds_hlist_for_each_entry(event_notifier_priv, node, head, hlist) {
1792                                 /*
1793                                  * Check if event_notifier already exists by checking
1794                                  * if the event_notifier and enabler share the same
1795                                  * description and id.
1796                                  */
1797                                 if (event_notifier_priv->parent.desc == desc &&
1798                                                 event_notifier_priv->parent.user_token == event_notifier_enabler->user_token) {
1799                                         found = true;
1800                                         break;
1801                                 }
1802                         }
1803
1804                         if (found)
1805                                 continue;
1806
1807                         /* Check that the probe supports event notifiers, else report the error. */
1808                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1809                                 ERR("Probe \"%s\" contains event \"%s\" which matches an enabled event notifier, "
1810                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1811                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1812                                         "this event will not generate any notification.",
1813                                         probe_desc->provider,
1814                                         desc->name,
1815                                         probe_desc->major,
1816                                         probe_desc->minor);
1817                                 continue;
1818                         }
1819                         /*
1820                          * We need to create a event_notifier for this event probe.
1821                          */
1822                         ret = lttng_event_notifier_create(desc,
1823                                 event_notifier_enabler->user_token,
1824                                 event_notifier_enabler->error_counter_index,
1825                                 event_notifier_group);
1826                         if (ret) {
1827                                 DBG("Unable to create event_notifier %s, error %d\n",
1828                                         probe_desc->event_desc[i]->name, ret);
1829                         }
1830                 }
1831         }
1832 }
1833
1834 /*
1835  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1836  */
1837 static
1838 int lttng_event_notifier_enabler_ref_event_notifiers(
1839                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1840 {
1841         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1842         struct lttng_ust_event_notifier_private *event_notifier_priv;
1843
1844          /*
1845           * Only try to create event_notifiers for enablers that are enabled, the user
1846           * might still be attaching filter or exclusion to the
1847           * event_notifier_enabler.
1848           */
1849         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1850                 goto end;
1851
1852         /* First, ensure that probe event_notifiers are created for this enabler. */
1853         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1854
1855         /* Link the created event_notifier with its associated enabler. */
1856         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1857                 struct lttng_enabler_ref *enabler_ref;
1858
1859                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier_priv->pub))
1860                         continue;
1861
1862                 enabler_ref = lttng_enabler_ref(&event_notifier_priv->parent.enablers_ref_head,
1863                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1864                 if (!enabler_ref) {
1865                         /*
1866                          * If no backward ref, create it.
1867                          * Add backward ref from event_notifier to enabler.
1868                          */
1869                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1870                         if (!enabler_ref)
1871                                 return -ENOMEM;
1872
1873                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1874                                 event_notifier_enabler);
1875                         cds_list_add(&enabler_ref->node,
1876                                 &event_notifier_priv->parent.enablers_ref_head);
1877                 }
1878
1879                 /*
1880                  * Link filter bytecodes if not linked yet.
1881                  */
1882                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1883                         &event_notifier_group->ctx,
1884                         &event_notifier_priv->pub->parent->filter_bytecode_runtime_head,
1885                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1886
1887                 /*
1888                  * Link capture bytecodes if not linked yet.
1889                  */
1890                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1891                         &event_notifier_group->ctx, &event_notifier_priv->pub->capture_bytecode_runtime_head,
1892                         &event_notifier_enabler->capture_bytecode_head);
1893
1894                 event_notifier_priv->num_captures = event_notifier_enabler->num_captures;
1895         }
1896 end:
1897         return 0;
1898 }
1899
1900 static
1901 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1902 {
1903         struct lttng_event_notifier_enabler *event_notifier_enabler;
1904         struct lttng_ust_event_notifier_private *event_notifier_priv;
1905
1906         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1907                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1908
1909         /*
1910          * For each event_notifier, if at least one of its enablers is enabled,
1911          * we enable the event_notifier, else we disable it.
1912          */
1913         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1914                 struct lttng_enabler_ref *enabler_ref;
1915                 struct lttng_bytecode_runtime *runtime;
1916                 int enabled = 0, has_enablers_without_bytecode = 0;
1917
1918                 /* Enable event_notifiers */
1919                 cds_list_for_each_entry(enabler_ref,
1920                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1921                         if (enabler_ref->ref->enabled) {
1922                                 enabled = 1;
1923                                 break;
1924                         }
1925                 }
1926
1927                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1928                 /*
1929                  * Sync tracepoint registration with event_notifier enabled
1930                  * state.
1931                  */
1932                 if (enabled) {
1933                         if (!event_notifier_priv->parent.registered)
1934                                 register_event_notifier(event_notifier_priv->pub);
1935                 } else {
1936                         if (event_notifier_priv->parent.registered)
1937                                 unregister_event_notifier(event_notifier_priv->pub);
1938                 }
1939
1940                 /* Check if has enablers without bytecode enabled */
1941                 cds_list_for_each_entry(enabler_ref,
1942                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1943                         if (enabler_ref->ref->enabled
1944                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1945                                 has_enablers_without_bytecode = 1;
1946                                 break;
1947                         }
1948                 }
1949                 event_notifier_priv->pub->parent->has_enablers_without_bytecode =
1950                         has_enablers_without_bytecode;
1951
1952                 /* Enable filters */
1953                 cds_list_for_each_entry(runtime,
1954                                 &event_notifier_priv->pub->parent->filter_bytecode_runtime_head, node) {
1955                         lttng_bytecode_filter_sync_state(runtime);
1956                 }
1957
1958                 /* Enable captures. */
1959                 cds_list_for_each_entry(runtime,
1960                                 &event_notifier_priv->pub->capture_bytecode_runtime_head, node) {
1961                         lttng_bytecode_capture_sync_state(runtime);
1962                 }
1963         }
1964         __tracepoint_probe_prune_release_queue();
1965 }
1966
1967 /*
1968  * Apply enablers to session events, adding events to session if need
1969  * be. It is required after each modification applied to an active
1970  * session, and right before session "start".
1971  * "lazy" sync means we only sync if required.
1972  */
1973 static
1974 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1975 {
1976         /* We can skip if session is not active */
1977         if (!session->active)
1978                 return;
1979         lttng_session_sync_event_enablers(session);
1980 }
1981
1982 /*
1983  * Update all sessions 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_session_provider(const char *name,
1990                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1991                 void (*record)(struct lttng_ctx_field *field,
1992                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1993                         struct lttng_channel *chan),
1994                 void (*get_value)(struct lttng_ctx_field *field,
1995                         struct lttng_ctx_value *value))
1996 {
1997         struct lttng_ust_session_private *session_priv;
1998
1999         cds_list_for_each_entry(session_priv, &sessions, node) {
2000                 struct lttng_channel *chan;
2001                 struct lttng_ust_event_recorder_private *event_recorder_priv;
2002                 int ret;
2003
2004                 ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
2005                                 name, get_size, record, get_value);
2006                 if (ret)
2007                         abort();
2008                 cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
2009                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
2010                                         name, get_size, record, get_value);
2011                         if (ret)
2012                                 abort();
2013                 }
2014                 cds_list_for_each_entry(event_recorder_priv, &session_priv->events_head, node) {
2015                         ret = lttng_ust_context_set_provider_rcu(&event_recorder_priv->pub->ctx,
2016                                         name, get_size, record, get_value);
2017                         if (ret)
2018                                 abort();
2019                 }
2020         }
2021 }
2022
2023 /*
2024  * Update all event_notifier groups with the given app context.
2025  * Called with ust lock held.
2026  * This is invoked when an application context gets loaded/unloaded. It
2027  * ensures the context callbacks are in sync with the application
2028  * context (either app context callbacks, or dummy callbacks).
2029  */
2030 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
2031                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
2032                 void (*record)(struct lttng_ctx_field *field,
2033                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
2034                         struct lttng_channel *chan),
2035                 void (*get_value)(struct lttng_ctx_field *field,
2036                         struct lttng_ctx_value *value))
2037 {
2038         struct lttng_event_notifier_group *event_notifier_group;
2039
2040         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2041                 int ret;
2042
2043                 ret = lttng_ust_context_set_provider_rcu(
2044                                 &event_notifier_group->ctx,
2045                                 name, get_size, record, get_value);
2046                 if (ret)
2047                         abort();
2048         }
2049 }