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->priv->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->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->run_filter = lttng_ust_interpret_event_filter;
 754         event_recorder->parent->enabled = 0;
 755         event_recorder->parent->priv->registered = 0;
 756         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->filter_bytecode_runtime_head);
 757         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 758         event_recorder->parent->priv->desc = desc;
 759
 760         if (desc->loglevel)
 761                 loglevel = *(*event_recorder->parent->priv->desc->loglevel);
 762         else
 763                 loglevel = TRACE_DEFAULT;
 764         if (desc->model_emf_uri)
 765                 uri = *(desc->model_emf_uri);
 766         else
 767                 uri = NULL;
 768
 769         /* Fetch event ID from sessiond */
 770         ret = ustcomm_register_event(notify_socket,
 771                 session,
 772                 session->priv->objd,
 773                 chan->priv->parent.objd,
 774                 desc->name,
 775                 loglevel,
 776                 desc->signature,
 777                 desc->nr_fields,
 778                 desc->fields,
 779                 uri,
 780                 &event_recorder->id);
 781         if (ret < 0) {
 782                 DBG("Error (%d) registering event to sessiond", ret);
 783                 goto sessiond_register_error;
 784         }
 785
 786         cds_list_add(&event_recorder_priv->node, &chan->parent->session->priv->events_head);
 787         cds_hlist_add_head(&event_recorder_priv->hlist, head);
 788         return 0;
 789
 790 sessiond_register_error:
 791         free(event_recorder_priv);
 792 priv_error:
 793         free(event_recorder->parent);
 794 parent_error:
 795         free(event_recorder);
 796 cache_error:
 797 create_enum_error:
 798 socket_error:
 799         return ret;
 800 }
 801
 802 static
 803 int lttng_event_notifier_create(struct lttng_ust_event_desc *desc,
 804                 uint64_t token, uint64_t error_counter_index,
 805                 struct lttng_event_notifier_group *event_notifier_group)
 806 {
 807         struct lttng_ust_event_notifier *event_notifier;
 808         struct lttng_ust_event_notifier_private *event_notifier_priv;
 809         struct cds_hlist_head *head;
 810         int ret = 0;
 811
 812         /*
 813          * Get the hashtable bucket the created lttng_event_notifier object
 814          * should be inserted.
 815          */
 816         head = borrow_hash_table_bucket(
 817                 event_notifier_group->event_notifiers_ht.table,
 818                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 819
 820         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 821         if (!event_notifier) {
 822                 ret = -ENOMEM;
 823                 goto error;
 824         }
 825         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 826
 827         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 828         if (!event_notifier->parent) {
 829                 ret = -ENOMEM;
 830                 goto parent_error;
 831         }
 832         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 833         event_notifier->parent->type = LTTNG_UST_EVENT_TYPE_NOTIFIER;
 834         event_notifier->parent->child = event_notifier;
 835
 836         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 837         if (!event_notifier_priv) {
 838                 ret = -ENOMEM;
 839                 goto priv_error;
 840         }
 841         event_notifier->priv = event_notifier_priv;
 842         event_notifier_priv->pub = event_notifier;
 843         event_notifier->parent->priv = &event_notifier_priv->parent;
 844         event_notifier_priv->parent.pub = event_notifier->parent;
 845
 846         event_notifier_priv->group = event_notifier_group;
 847         event_notifier_priv->parent.user_token = token;
 848         event_notifier_priv->error_counter_index = error_counter_index;
 849
 850         /* Event notifier will be enabled by enabler sync. */
 851         event_notifier->parent->run_filter = lttng_ust_interpret_event_filter;
 852         event_notifier->parent->enabled = 0;
 853         event_notifier_priv->parent.registered = 0;
 854
 855         CDS_INIT_LIST_HEAD(&event_notifier->parent->priv->filter_bytecode_runtime_head);
 856         CDS_INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
 857         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 858         event_notifier_priv->parent.desc = desc;
 859         event_notifier->notification_send = lttng_event_notifier_notification_send;
 860
 861         cds_list_add(&event_notifier_priv->node,
 862                         &event_notifier_group->event_notifiers_head);
 863         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 864
 865         return 0;
 866
 867 priv_error:
 868         free(event_notifier->parent);
 869 parent_error:
 870         free(event_notifier);
 871 error:
 872         return ret;
 873 }
 874
 875 static
 876 int lttng_desc_match_star_glob_enabler(struct lttng_ust_event_desc *desc,
 877                 struct lttng_enabler *enabler)
 878 {
 879         int loglevel = 0;
 880         unsigned int has_loglevel = 0;
 881
 882         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 883         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 884                         desc->name, SIZE_MAX))
 885                 return 0;
 886         if (desc->loglevel) {
 887                 loglevel = *(*desc->loglevel);
 888                 has_loglevel = 1;
 889         }
 890         if (!lttng_loglevel_match(loglevel,
 891                         has_loglevel,
 892                         enabler->event_param.loglevel_type,
 893                         enabler->event_param.loglevel))
 894                 return 0;
 895         return 1;
 896 }
 897
 898 static
 899 int lttng_desc_match_event_enabler(struct lttng_ust_event_desc *desc,
 900                 struct lttng_enabler *enabler)
 901 {
 902         int loglevel = 0;
 903         unsigned int has_loglevel = 0;
 904
 905         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 906         if (strcmp(desc->name, enabler->event_param.name))
 907                 return 0;
 908         if (desc->loglevel) {
 909                 loglevel = *(*desc->loglevel);
 910                 has_loglevel = 1;
 911         }
 912         if (!lttng_loglevel_match(loglevel,
 913                         has_loglevel,
 914                         enabler->event_param.loglevel_type,
 915                         enabler->event_param.loglevel))
 916                 return 0;
 917         return 1;
 918 }
 919
 920 static
 921 int lttng_desc_match_enabler(struct lttng_ust_event_desc *desc,
 922                 struct lttng_enabler *enabler)
 923 {
 924         switch (enabler->format_type) {
 925         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 926         {
 927                 struct lttng_ust_excluder_node *excluder;
 928
 929                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 930                         return 0;
 931                 }
 932
 933                 /*
 934                  * If the matching event matches with an excluder,
 935                  * return 'does not match'
 936                  */
 937                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 938                         int count;
 939
 940                         for (count = 0; count < excluder->excluder.count; count++) {
 941                                 int len;
 942                                 char *excluder_name;
 943
 944                                 excluder_name = (char *) (excluder->excluder.names)
 945                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
 946                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 947                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 948                                         return 0;
 949                         }
 950                 }
 951                 return 1;
 952         }
 953         case LTTNG_ENABLER_FORMAT_EVENT:
 954                 return lttng_desc_match_event_enabler(desc, enabler);
 955         default:
 956                 return -EINVAL;
 957         }
 958 }
 959
 960 static
 961 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 962                 struct lttng_ust_event_recorder *event_recorder)
 963 {
 964         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
 965                         lttng_event_enabler_as_enabler(event_enabler))
 966                         && event_recorder->chan == event_enabler->chan)
 967                 return 1;
 968         else
 969                 return 0;
 970 }
 971
 972 static
 973 int lttng_event_notifier_enabler_match_event_notifier(
 974                 struct lttng_event_notifier_enabler *event_notifier_enabler,
 975                 struct lttng_ust_event_notifier *event_notifier)
 976 {
 977         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
 978                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 979
 980         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
 981                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
 982                 return 1;
 983         else
 984                 return 0;
 985 }
 986
 987 static
 988 struct lttng_enabler_ref *lttng_enabler_ref(
 989                 struct cds_list_head *enabler_ref_list,
 990                 struct lttng_enabler *enabler)
 991 {
 992         struct lttng_enabler_ref *enabler_ref;
 993
 994         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
 995                 if (enabler_ref->ref == enabler)
 996                         return enabler_ref;
 997         }
 998         return NULL;
 999 }
1000
1001 /*
1002  * Create struct lttng_event if it is missing and present in the list of
1003  * tracepoint probes.
1004  */
1005 static
1006 void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_enabler)
1007 {
1008         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1009         struct lttng_ust_probe_desc *probe_desc;
1010         struct lttng_ust_event_desc *desc;
1011         struct lttng_ust_event_recorder_private *event_recorder_priv;
1012         int i;
1013         struct cds_list_head *probe_list;
1014
1015         probe_list = lttng_get_probe_list_head();
1016         /*
1017          * For each probe event, if we find that a probe event matches
1018          * our enabler, create an associated lttng_event if not
1019          * already present.
1020          */
1021         cds_list_for_each_entry(probe_desc, probe_list, head) {
1022                 for (i = 0; i < probe_desc->nr_events; i++) {
1023                         int ret;
1024                         bool found = false;
1025                         struct cds_hlist_head *head;
1026                         struct cds_hlist_node *node;
1027
1028                         desc = probe_desc->event_desc[i];
1029                         if (!lttng_desc_match_enabler(desc,
1030                                         lttng_event_enabler_as_enabler(event_enabler)))
1031                                 continue;
1032
1033                         head = borrow_hash_table_bucket(
1034                                 session->priv->events_ht.table,
1035                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1036
1037                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1038                                 if (event_recorder_priv->parent.desc == desc
1039                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1040                                         found = true;
1041                                         break;
1042                                 }
1043                         }
1044                         if (found)
1045                                 continue;
1046
1047                         /*
1048                          * We need to create an event for this
1049                          * event probe.
1050                          */
1051                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1052                                         event_enabler->chan);
1053                         if (ret) {
1054                                 DBG("Unable to create event %s, error %d\n",
1055                                         probe_desc->event_desc[i]->name, ret);
1056                         }
1057                 }
1058         }
1059 }
1060
1061 static
1062 void probe_provider_event_for_each(struct lttng_ust_probe_desc *provider_desc,
1063                 void (*event_func)(struct lttng_ust_event_common *event))
1064 {
1065         struct cds_hlist_node *node, *tmp_node;
1066         struct cds_list_head *sessionsp;
1067         unsigned int i;
1068
1069         /* Get handle on list of sessions. */
1070         sessionsp = lttng_get_sessions();
1071
1072         /*
1073          * Iterate over all events in the probe provider descriptions and
1074          * sessions to queue the unregistration of the events.
1075          */
1076         for (i = 0; i < provider_desc->nr_events; i++) {
1077                 struct lttng_ust_event_desc *event_desc;
1078                 struct lttng_event_notifier_group *event_notifier_group;
1079                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1080                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1081                 struct lttng_ust_session_private *session_priv;
1082                 struct cds_hlist_head *head;
1083
1084                 event_desc = provider_desc->event_desc[i];
1085
1086                 /*
1087                  * Iterate over all session to find the current event
1088                  * description.
1089                  */
1090                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1091                         /*
1092                          * Get the list of events in the hashtable bucket and
1093                          * iterate to find the event matching this descriptor.
1094                          */
1095                         head = borrow_hash_table_bucket(
1096                                 session_priv->events_ht.table,
1097                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1098
1099                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1100                                 if (event_desc == event_recorder_priv->parent.desc) {
1101                                         event_func(event_recorder_priv->parent.pub);
1102                                         break;
1103                                 }
1104                         }
1105                 }
1106
1107                 /*
1108                  * Iterate over all event_notifier groups to find the current event
1109                  * description.
1110                  */
1111                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1112                         /*
1113                          * Get the list of event_notifiers in the hashtable bucket and
1114                          * iterate to find the event_notifier matching this
1115                          * descriptor.
1116                          */
1117                         head = borrow_hash_table_bucket(
1118                                 event_notifier_group->event_notifiers_ht.table,
1119                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1120
1121                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1122                                 if (event_desc == event_notifier_priv->parent.desc) {
1123                                         event_func(event_notifier_priv->parent.pub);
1124                                         break;
1125                                 }
1126                         }
1127                 }
1128         }
1129 }
1130
1131 static
1132 void _event_enum_destroy(struct lttng_ust_event_common *event)
1133 {
1134
1135         switch (event->type) {
1136         case LTTNG_UST_EVENT_TYPE_RECORDER:
1137         {
1138                 struct lttng_ust_event_recorder *event_recorder = event->child;
1139                 struct lttng_ust_session *session = event_recorder->chan->parent->session;
1140                 unsigned int i;
1141
1142                 /* Destroy enums of the current event. */
1143                 for (i = 0; i < event_recorder->parent->priv->desc->nr_fields; i++) {
1144                         struct lttng_ust_enum_desc *enum_desc;
1145                         struct lttng_ust_event_field *field;
1146                         struct lttng_enum *curr_enum;
1147
1148                         field = event_recorder->parent->priv->desc->fields[i];
1149                         switch (field->type->type) {
1150                         case lttng_ust_type_enum:
1151                                 enum_desc = lttng_ust_get_type_enum(field->type)->desc;
1152                                 break;
1153                         default:
1154                                 continue;
1155                         }
1156
1157                         curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1158                         if (curr_enum) {
1159                                 _lttng_enum_destroy(curr_enum);
1160                         }
1161                 }
1162                 break;
1163         }
1164         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1165                 break;
1166         default:
1167                 abort();
1168         }
1169         /* Destroy event. */
1170         _lttng_event_destroy(event);
1171 }
1172
1173 /*
1174  * Iterate over all the UST sessions to unregister and destroy all probes from
1175  * the probe provider descriptor received as argument. Must me called with the
1176  * ust_lock held.
1177  */
1178 void lttng_probe_provider_unregister_events(
1179                 struct lttng_ust_probe_desc *provider_desc)
1180 {
1181         /*
1182          * Iterate over all events in the probe provider descriptions and sessions
1183          * to queue the unregistration of the events.
1184          */
1185         probe_provider_event_for_each(provider_desc, _lttng_event_unregister);
1186
1187         /* Wait for grace period. */
1188         lttng_ust_urcu_synchronize_rcu();
1189         /* Prune the unregistration queue. */
1190         lttng_ust_tp_probe_prune_release_queue();
1191
1192         /*
1193          * It is now safe to destroy the events and remove them from the event list
1194          * and hashtables.
1195          */
1196         probe_provider_event_for_each(provider_desc, _event_enum_destroy);
1197 }
1198
1199 /*
1200  * Create events associated with an event enabler (if not already present),
1201  * and add backward reference from the event to the enabler.
1202  */
1203 static
1204 int lttng_event_enabler_ref_event_recorders(struct lttng_event_enabler *event_enabler)
1205 {
1206         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1207         struct lttng_ust_event_recorder_private *event_recorder_priv;
1208
1209         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1210                 goto end;
1211
1212         /* First ensure that probe events are created for this enabler. */
1213         lttng_create_event_recorder_if_missing(event_enabler);
1214
1215         /* For each event matching enabler in session event list. */
1216         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1217                 struct lttng_enabler_ref *enabler_ref;
1218
1219                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1220                         continue;
1221
1222                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1223                         lttng_event_enabler_as_enabler(event_enabler));
1224                 if (!enabler_ref) {
1225                         /*
1226                          * If no backward ref, create it.
1227                          * Add backward ref from event to enabler.
1228                          */
1229                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1230                         if (!enabler_ref)
1231                                 return -ENOMEM;
1232                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1233                                 event_enabler);
1234                         cds_list_add(&enabler_ref->node,
1235                                 &event_recorder_priv->parent.enablers_ref_head);
1236                 }
1237
1238                 /*
1239                  * Link filter bytecodes if not linked yet.
1240                  */
1241                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1242                         &session->priv->ctx,
1243                         &event_recorder_priv->parent.filter_bytecode_runtime_head,
1244                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1245
1246                 /* TODO: merge event context. */
1247         }
1248 end:
1249         return 0;
1250 }
1251
1252 /*
1253  * Called at library load: connect the probe on all enablers matching
1254  * this event.
1255  * Called with session mutex held.
1256  */
1257 int lttng_fix_pending_events(void)
1258 {
1259         struct lttng_ust_session_private *session_priv;
1260
1261         cds_list_for_each_entry(session_priv, &sessions, node) {
1262                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1263         }
1264         return 0;
1265 }
1266
1267 int lttng_fix_pending_event_notifiers(void)
1268 {
1269         struct lttng_event_notifier_group *event_notifier_group;
1270
1271         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1272                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1273         }
1274         return 0;
1275 }
1276
1277 /*
1278  * For each session of the owner thread, execute pending statedump.
1279  * Only dump state for the sessions owned by the caller thread, because
1280  * we don't keep ust_lock across the entire iteration.
1281  */
1282 void lttng_handle_pending_statedump(void *owner)
1283 {
1284         struct lttng_ust_session_private *session_priv;
1285
1286         /* Execute state dump */
1287         do_lttng_ust_statedump(owner);
1288
1289         /* Clear pending state dump */
1290         if (ust_lock()) {
1291                 goto end;
1292         }
1293         cds_list_for_each_entry(session_priv, &sessions, node) {
1294                 if (session_priv->owner != owner)
1295                         continue;
1296                 if (!session_priv->statedump_pending)
1297                         continue;
1298                 session_priv->statedump_pending = 0;
1299         }
1300 end:
1301         ust_unlock();
1302         return;
1303 }
1304
1305 static
1306 void _lttng_event_destroy(struct lttng_ust_event_common *event)
1307 {
1308         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1309
1310         lttng_free_event_filter_runtime(event);
1311         /* Free event enabler refs */
1312         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1313                         &event->priv->enablers_ref_head, node)
1314                 free(enabler_ref);
1315
1316         switch (event->type) {
1317         case LTTNG_UST_EVENT_TYPE_RECORDER:
1318         {
1319                 struct lttng_ust_event_recorder *event_recorder = event->child;
1320
1321                 /* Remove from event list. */
1322                 cds_list_del(&event_recorder->priv->node);
1323                 /* Remove from event hash table. */
1324                 cds_hlist_del(&event_recorder->priv->hlist);
1325
1326                 lttng_destroy_context(event_recorder->priv->ctx);
1327                 free(event_recorder->parent);
1328                 free(event_recorder->priv);
1329                 free(event_recorder);
1330                 break;
1331         }
1332         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1333         {
1334                 struct lttng_ust_event_notifier *event_notifier = event->child;
1335
1336                 /* Remove from event list. */
1337                 cds_list_del(&event_notifier->priv->node);
1338                 /* Remove from event hash table. */
1339                 cds_hlist_del(&event_notifier->priv->hlist);
1340
1341                 free(event_notifier->priv);
1342                 free(event_notifier->parent);
1343                 free(event_notifier);
1344                 break;
1345         }
1346         default:
1347                 abort();
1348         }
1349 }
1350
1351 static
1352 void _lttng_enum_destroy(struct lttng_enum *_enum)
1353 {
1354         cds_list_del(&_enum->node);
1355         cds_hlist_del(&_enum->hlist);
1356         free(_enum);
1357 }
1358
1359 void lttng_ust_abi_events_exit(void)
1360 {
1361         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1362
1363         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1364                 lttng_session_destroy(session_priv->pub);
1365 }
1366
1367 /*
1368  * Enabler management.
1369  */
1370 struct lttng_event_enabler *lttng_event_enabler_create(
1371                 enum lttng_enabler_format_type format_type,
1372                 struct lttng_ust_abi_event *event_param,
1373                 struct lttng_ust_channel_buffer *chan)
1374 {
1375         struct lttng_event_enabler *event_enabler;
1376
1377         event_enabler = zmalloc(sizeof(*event_enabler));
1378         if (!event_enabler)
1379                 return NULL;
1380         event_enabler->base.format_type = format_type;
1381         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1382         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1383         memcpy(&event_enabler->base.event_param, event_param,
1384                 sizeof(event_enabler->base.event_param));
1385         event_enabler->chan = chan;
1386         /* ctx left NULL */
1387         event_enabler->base.enabled = 0;
1388         cds_list_add(&event_enabler->node, &event_enabler->chan->parent->session->priv->enablers_head);
1389         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1390
1391         return event_enabler;
1392 }
1393
1394 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1395                 struct lttng_event_notifier_group *event_notifier_group,
1396                 enum lttng_enabler_format_type format_type,
1397                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1398 {
1399         struct lttng_event_notifier_enabler *event_notifier_enabler;
1400
1401         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1402         if (!event_notifier_enabler)
1403                 return NULL;
1404         event_notifier_enabler->base.format_type = format_type;
1405         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1406         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1407         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1408
1409         event_notifier_enabler->user_token = event_notifier_param->event.token;
1410         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1411         event_notifier_enabler->num_captures = 0;
1412
1413         memcpy(&event_notifier_enabler->base.event_param.name,
1414                 event_notifier_param->event.name,
1415                 sizeof(event_notifier_enabler->base.event_param.name));
1416         event_notifier_enabler->base.event_param.instrumentation =
1417                 event_notifier_param->event.instrumentation;
1418         event_notifier_enabler->base.event_param.loglevel =
1419                 event_notifier_param->event.loglevel;
1420         event_notifier_enabler->base.event_param.loglevel_type =
1421                 event_notifier_param->event.loglevel_type;
1422
1423         event_notifier_enabler->base.enabled = 0;
1424         event_notifier_enabler->group = event_notifier_group;
1425
1426         cds_list_add(&event_notifier_enabler->node,
1427                         &event_notifier_group->enablers_head);
1428
1429         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1430
1431         return event_notifier_enabler;
1432 }
1433
1434 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1435 {
1436         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1437         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1438
1439         return 0;
1440 }
1441
1442 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1443 {
1444         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1445         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1446
1447         return 0;
1448 }
1449
1450 static
1451 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1452                 struct lttng_ust_bytecode_node **bytecode)
1453 {
1454         (*bytecode)->enabler = enabler;
1455         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1456         /* Take ownership of bytecode */
1457         *bytecode = NULL;
1458 }
1459
1460 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1461                 struct lttng_ust_bytecode_node **bytecode)
1462 {
1463         _lttng_enabler_attach_filter_bytecode(
1464                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1465
1466         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1467         return 0;
1468 }
1469
1470 static
1471 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1472                 struct lttng_ust_excluder_node **excluder)
1473 {
1474         (*excluder)->enabler = enabler;
1475         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1476         /* Take ownership of excluder */
1477         *excluder = NULL;
1478 }
1479
1480 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1481                 struct lttng_ust_excluder_node **excluder)
1482 {
1483         _lttng_enabler_attach_exclusion(
1484                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1485
1486         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1487         return 0;
1488 }
1489
1490 int lttng_event_notifier_enabler_enable(
1491                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1492 {
1493         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1494         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1495
1496         return 0;
1497 }
1498
1499 int lttng_event_notifier_enabler_disable(
1500                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1501 {
1502         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1503         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1504
1505         return 0;
1506 }
1507
1508 int lttng_event_notifier_enabler_attach_filter_bytecode(
1509                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1510                 struct lttng_ust_bytecode_node **bytecode)
1511 {
1512         _lttng_enabler_attach_filter_bytecode(
1513                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1514                 bytecode);
1515
1516         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1517         return 0;
1518 }
1519
1520 int lttng_event_notifier_enabler_attach_capture_bytecode(
1521                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1522                 struct lttng_ust_bytecode_node **bytecode)
1523 {
1524         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1525                         event_notifier_enabler);
1526         cds_list_add_tail(&(*bytecode)->node,
1527                         &event_notifier_enabler->capture_bytecode_head);
1528         /* Take ownership of bytecode */
1529         *bytecode = NULL;
1530         event_notifier_enabler->num_captures++;
1531
1532         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1533         return 0;
1534 }
1535
1536 int lttng_event_notifier_enabler_attach_exclusion(
1537                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1538                 struct lttng_ust_excluder_node **excluder)
1539 {
1540         _lttng_enabler_attach_exclusion(
1541                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1542                 excluder);
1543
1544         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1545         return 0;
1546 }
1547
1548 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1549                 union lttng_ust_abi_args *uargs,
1550                 struct lttng_ust_ctx **ctx, struct lttng_ust_session *session)
1551 {
1552         /*
1553          * We cannot attach a context after trace has been started for a
1554          * session because the metadata does not allow expressing this
1555          * information outside of the original channel scope.
1556          */
1557         if (session->priv->been_active)
1558                 return -EPERM;
1559
1560         switch (context_param->ctx) {
1561         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1562                 return lttng_add_pthread_id_to_ctx(ctx);
1563         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1564         {
1565                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1566
1567                 perf_ctx_param = &context_param->u.perf_counter;
1568                 return lttng_add_perf_counter_to_ctx(
1569                         perf_ctx_param->type,
1570                         perf_ctx_param->config,
1571                         perf_ctx_param->name,
1572                         ctx);
1573         }
1574         case LTTNG_UST_ABI_CONTEXT_VTID:
1575                 return lttng_add_vtid_to_ctx(ctx);
1576         case LTTNG_UST_ABI_CONTEXT_VPID:
1577                 return lttng_add_vpid_to_ctx(ctx);
1578         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1579                 return lttng_add_procname_to_ctx(ctx);
1580         case LTTNG_UST_ABI_CONTEXT_IP:
1581                 return lttng_add_ip_to_ctx(ctx);
1582         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1583                 return lttng_add_cpu_id_to_ctx(ctx);
1584         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1585                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1586                         ctx);
1587         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1588                 return lttng_add_cgroup_ns_to_ctx(ctx);
1589         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1590                 return lttng_add_ipc_ns_to_ctx(ctx);
1591         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1592                 return lttng_add_mnt_ns_to_ctx(ctx);
1593         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1594                 return lttng_add_net_ns_to_ctx(ctx);
1595         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1596                 return lttng_add_pid_ns_to_ctx(ctx);
1597         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1598                 return lttng_add_time_ns_to_ctx(ctx);
1599         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1600                 return lttng_add_user_ns_to_ctx(ctx);
1601         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1602                 return lttng_add_uts_ns_to_ctx(ctx);
1603         case LTTNG_UST_ABI_CONTEXT_VUID:
1604                 return lttng_add_vuid_to_ctx(ctx);
1605         case LTTNG_UST_ABI_CONTEXT_VEUID:
1606                 return lttng_add_veuid_to_ctx(ctx);
1607         case LTTNG_UST_ABI_CONTEXT_VSUID:
1608                 return lttng_add_vsuid_to_ctx(ctx);
1609         case LTTNG_UST_ABI_CONTEXT_VGID:
1610                 return lttng_add_vgid_to_ctx(ctx);
1611         case LTTNG_UST_ABI_CONTEXT_VEGID:
1612                 return lttng_add_vegid_to_ctx(ctx);
1613         case LTTNG_UST_ABI_CONTEXT_VSGID:
1614                 return lttng_add_vsgid_to_ctx(ctx);
1615         default:
1616                 return -EINVAL;
1617         }
1618 }
1619
1620 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1621                 struct lttng_ust_abi_context *context_param)
1622 {
1623         return -ENOSYS;
1624 }
1625
1626 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1627 {
1628         if (!event_enabler) {
1629                 return;
1630         }
1631         cds_list_del(&event_enabler->node);
1632
1633         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1634
1635         lttng_destroy_context(event_enabler->ctx);
1636         free(event_enabler);
1637 }
1638
1639 /*
1640  * lttng_session_sync_event_enablers should be called just before starting a
1641  * session.
1642  */
1643 static
1644 void lttng_session_sync_event_enablers(struct lttng_ust_session *session)
1645 {
1646         struct lttng_event_enabler *event_enabler;
1647         struct lttng_ust_event_recorder_private *event_recorder_priv;
1648
1649         cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
1650                 lttng_event_enabler_ref_event_recorders(event_enabler);
1651         /*
1652          * For each event, if at least one of its enablers is enabled,
1653          * and its channel and session transient states are enabled, we
1654          * enable the event, else we disable it.
1655          */
1656         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1657                 struct lttng_enabler_ref *enabler_ref;
1658                 struct lttng_ust_bytecode_runtime *runtime;
1659                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1660                 int nr_filters = 0;
1661
1662                 /* Enable events */
1663                 cds_list_for_each_entry(enabler_ref,
1664                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1665                         if (enabler_ref->ref->enabled) {
1666                                 enabled = 1;
1667                                 break;
1668                         }
1669                 }
1670                 /*
1671                  * Enabled state is based on union of enablers, with
1672                  * intesection of session and channel transient enable
1673                  * states.
1674                  */
1675                 enabled = enabled && session->priv->tstate && event_recorder_priv->pub->chan->priv->parent.tstate;
1676
1677                 CMM_STORE_SHARED(event_recorder_priv->pub->parent->enabled, enabled);
1678                 /*
1679                  * Sync tracepoint registration with event enabled
1680                  * state.
1681                  */
1682                 if (enabled) {
1683                         if (!event_recorder_priv->parent.registered)
1684                                 register_event(event_recorder_priv->parent.pub);
1685                 } else {
1686                         if (event_recorder_priv->parent.registered)
1687                                 unregister_event(event_recorder_priv->parent.pub);
1688                 }
1689
1690                 /* Check if has enablers without bytecode enabled */
1691                 cds_list_for_each_entry(enabler_ref,
1692                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1693                         if (enabler_ref->ref->enabled
1694                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1695                                 has_enablers_without_filter_bytecode = 1;
1696                                 break;
1697                         }
1698                 }
1699                 event_recorder_priv->parent.has_enablers_without_filter_bytecode =
1700                         has_enablers_without_filter_bytecode;
1701
1702                 /* Enable filters */
1703                 cds_list_for_each_entry(runtime,
1704                                 &event_recorder_priv->parent.filter_bytecode_runtime_head, node) {
1705                         lttng_bytecode_sync_state(runtime);
1706                         nr_filters++;
1707                 }
1708                 CMM_STORE_SHARED(event_recorder_priv->parent.pub->eval_filter,
1709                         !(has_enablers_without_filter_bytecode || !nr_filters));
1710         }
1711         lttng_ust_tp_probe_prune_release_queue();
1712 }
1713
1714 /* Support for event notifier is introduced by probe provider major version 2. */
1715 static
1716 bool lttng_ust_probe_supports_event_notifier(struct lttng_ust_probe_desc *probe_desc)
1717 {
1718         return probe_desc->major >= 2;
1719 }
1720
1721 static
1722 void lttng_create_event_notifier_if_missing(
1723                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1724 {
1725         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1726         struct lttng_ust_probe_desc *probe_desc;
1727         struct cds_list_head *probe_list;
1728         int i;
1729
1730         probe_list = lttng_get_probe_list_head();
1731
1732         cds_list_for_each_entry(probe_desc, probe_list, head) {
1733                 for (i = 0; i < probe_desc->nr_events; i++) {
1734                         int ret;
1735                         bool found = false;
1736                         struct lttng_ust_event_desc *desc;
1737                         struct lttng_ust_event_notifier_private *event_notifier_priv;
1738                         struct cds_hlist_head *head;
1739                         struct cds_hlist_node *node;
1740
1741                         desc = probe_desc->event_desc[i];
1742
1743                         if (!lttng_desc_match_enabler(desc,
1744                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1745                                 continue;
1746
1747                         /*
1748                          * Given the current event_notifier group, get the bucket that
1749                          * the target event_notifier would be if it was already
1750                          * created.
1751                          */
1752                         head = borrow_hash_table_bucket(
1753                                 event_notifier_group->event_notifiers_ht.table,
1754                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1755
1756                         cds_hlist_for_each_entry(event_notifier_priv, node, head, hlist) {
1757                                 /*
1758                                  * Check if event_notifier already exists by checking
1759                                  * if the event_notifier and enabler share the same
1760                                  * description and id.
1761                                  */
1762                                 if (event_notifier_priv->parent.desc == desc &&
1763                                                 event_notifier_priv->parent.user_token == event_notifier_enabler->user_token) {
1764                                         found = true;
1765                                         break;
1766                                 }
1767                         }
1768
1769                         if (found)
1770                                 continue;
1771
1772                         /* Check that the probe supports event notifiers, else report the error. */
1773                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1774                                 ERR("Probe \"%s\" contains event \"%s\" which matches an enabled event notifier, "
1775                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1776                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1777                                         "this event will not generate any notification.",
1778                                         probe_desc->provider,
1779                                         desc->name,
1780                                         probe_desc->major,
1781                                         probe_desc->minor);
1782                                 continue;
1783                         }
1784                         /*
1785                          * We need to create a event_notifier for this event probe.
1786                          */
1787                         ret = lttng_event_notifier_create(desc,
1788                                 event_notifier_enabler->user_token,
1789                                 event_notifier_enabler->error_counter_index,
1790                                 event_notifier_group);
1791                         if (ret) {
1792                                 DBG("Unable to create event_notifier %s, error %d\n",
1793                                         probe_desc->event_desc[i]->name, ret);
1794                         }
1795                 }
1796         }
1797 }
1798
1799 /*
1800  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1801  */
1802 static
1803 int lttng_event_notifier_enabler_ref_event_notifiers(
1804                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1805 {
1806         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1807         struct lttng_ust_event_notifier_private *event_notifier_priv;
1808
1809          /*
1810           * Only try to create event_notifiers for enablers that are enabled, the user
1811           * might still be attaching filter or exclusion to the
1812           * event_notifier_enabler.
1813           */
1814         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1815                 goto end;
1816
1817         /* First, ensure that probe event_notifiers are created for this enabler. */
1818         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1819
1820         /* Link the created event_notifier with its associated enabler. */
1821         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1822                 struct lttng_enabler_ref *enabler_ref;
1823
1824                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier_priv->pub))
1825                         continue;
1826
1827                 enabler_ref = lttng_enabler_ref(&event_notifier_priv->parent.enablers_ref_head,
1828                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1829                 if (!enabler_ref) {
1830                         /*
1831                          * If no backward ref, create it.
1832                          * Add backward ref from event_notifier to enabler.
1833                          */
1834                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1835                         if (!enabler_ref)
1836                                 return -ENOMEM;
1837
1838                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1839                                 event_notifier_enabler);
1840                         cds_list_add(&enabler_ref->node,
1841                                 &event_notifier_priv->parent.enablers_ref_head);
1842                 }
1843
1844                 /*
1845                  * Link filter bytecodes if not linked yet.
1846                  */
1847                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1848                         &event_notifier_group->ctx,
1849                         &event_notifier_priv->parent.filter_bytecode_runtime_head,
1850                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1851
1852                 /*
1853                  * Link capture bytecodes if not linked yet.
1854                  */
1855                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1856                         &event_notifier_group->ctx, &event_notifier_priv->capture_bytecode_runtime_head,
1857                         &event_notifier_enabler->capture_bytecode_head);
1858
1859                 event_notifier_priv->num_captures = event_notifier_enabler->num_captures;
1860         }
1861 end:
1862         return 0;
1863 }
1864
1865 static
1866 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1867 {
1868         struct lttng_event_notifier_enabler *event_notifier_enabler;
1869         struct lttng_ust_event_notifier_private *event_notifier_priv;
1870
1871         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1872                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1873
1874         /*
1875          * For each event_notifier, if at least one of its enablers is enabled,
1876          * we enable the event_notifier, else we disable it.
1877          */
1878         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1879                 struct lttng_enabler_ref *enabler_ref;
1880                 struct lttng_ust_bytecode_runtime *runtime;
1881                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1882                 int nr_filters = 0, nr_captures = 0;
1883
1884                 /* Enable event_notifiers */
1885                 cds_list_for_each_entry(enabler_ref,
1886                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1887                         if (enabler_ref->ref->enabled) {
1888                                 enabled = 1;
1889                                 break;
1890                         }
1891                 }
1892
1893                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1894                 /*
1895                  * Sync tracepoint registration with event_notifier enabled
1896                  * state.
1897                  */
1898                 if (enabled) {
1899                         if (!event_notifier_priv->parent.registered)
1900                                 register_event(event_notifier_priv->parent.pub);
1901                 } else {
1902                         if (event_notifier_priv->parent.registered)
1903                                 unregister_event(event_notifier_priv->parent.pub);
1904                 }
1905
1906                 /* Check if has enablers without bytecode enabled */
1907                 cds_list_for_each_entry(enabler_ref,
1908                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1909                         if (enabler_ref->ref->enabled
1910                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1911                                 has_enablers_without_filter_bytecode = 1;
1912                                 break;
1913                         }
1914                 }
1915                 event_notifier_priv->parent.has_enablers_without_filter_bytecode =
1916                         has_enablers_without_filter_bytecode;
1917
1918                 /* Enable filters */
1919                 cds_list_for_each_entry(runtime,
1920                                 &event_notifier_priv->parent.filter_bytecode_runtime_head, node) {
1921                         lttng_bytecode_sync_state(runtime);
1922                         nr_filters++;
1923                 }
1924                 CMM_STORE_SHARED(event_notifier_priv->parent.pub->eval_filter,
1925                         !(has_enablers_without_filter_bytecode || !nr_filters));
1926
1927                 /* Enable captures. */
1928                 cds_list_for_each_entry(runtime,
1929                                 &event_notifier_priv->capture_bytecode_runtime_head, node) {
1930                         lttng_bytecode_sync_state(runtime);
1931                         nr_captures++;
1932                 }
1933                 CMM_STORE_SHARED(event_notifier_priv->pub->eval_capture,
1934                                 !!nr_captures);
1935         }
1936         lttng_ust_tp_probe_prune_release_queue();
1937 }
1938
1939 /*
1940  * Apply enablers to session events, adding events to session if need
1941  * be. It is required after each modification applied to an active
1942  * session, and right before session "start".
1943  * "lazy" sync means we only sync if required.
1944  */
1945 static
1946 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session)
1947 {
1948         /* We can skip if session is not active */
1949         if (!session->active)
1950                 return;
1951         lttng_session_sync_event_enablers(session);
1952 }
1953
1954 /*
1955  * Update all sessions with the given app context.
1956  * Called with ust lock held.
1957  * This is invoked when an application context gets loaded/unloaded. It
1958  * ensures the context callbacks are in sync with the application
1959  * context (either app context callbacks, or dummy callbacks).
1960  */
1961 void lttng_ust_context_set_session_provider(const char *name,
1962                 size_t (*get_size)(struct lttng_ust_ctx_field *field, size_t offset),
1963                 void (*record)(struct lttng_ust_ctx_field *field,
1964                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1965                         struct lttng_ust_channel_buffer *chan),
1966                 void (*get_value)(struct lttng_ust_ctx_field *field,
1967                         struct lttng_ust_ctx_value *value))
1968 {
1969         struct lttng_ust_session_private *session_priv;
1970
1971         cds_list_for_each_entry(session_priv, &sessions, node) {
1972                 struct lttng_ust_channel_buffer_private *chan;
1973                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1974                 int ret;
1975
1976                 ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
1977                                 name, get_size, record, get_value);
1978                 if (ret)
1979                         abort();
1980                 cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
1981                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1982                                         name, get_size, record, get_value);
1983                         if (ret)
1984                                 abort();
1985                 }
1986                 cds_list_for_each_entry(event_recorder_priv, &session_priv->events_head, node) {
1987                         ret = lttng_ust_context_set_provider_rcu(&event_recorder_priv->ctx,
1988                                         name, get_size, record, get_value);
1989                         if (ret)
1990                                 abort();
1991                 }
1992         }
1993 }
1994
1995 /*
1996  * Update all event_notifier groups with the given app context.
1997  * Called with ust lock held.
1998  * This is invoked when an application context gets loaded/unloaded. It
1999  * ensures the context callbacks are in sync with the application
2000  * context (either app context callbacks, or dummy callbacks).
2001  */
2002 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
2003                 size_t (*get_size)(struct lttng_ust_ctx_field *field, size_t offset),
2004                 void (*record)(struct lttng_ust_ctx_field *field,
2005                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
2006                         struct lttng_ust_channel_buffer *chan),
2007                 void (*get_value)(struct lttng_ust_ctx_field *field,
2008                         struct lttng_ust_ctx_value *value))
2009 {
2010         struct lttng_event_notifier_group *event_notifier_group;
2011
2012         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2013                 int ret;
2014
2015                 ret = lttng_ust_context_set_provider_rcu(
2016                                 &event_notifier_group->ctx,
2017                                 name, get_size, record, get_value);
2018                 if (ret)
2019                         abort();
2020         }
2021 }