src/lib/lttng-ust/lttng-events.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Holds LTTng per-session event registry.
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <stdio.h>
  11 #include <assert.h>
  12 #include <errno.h>
  13 #include <limits.h>
  14 #include <pthread.h>
  15 #include <sys/shm.h>
  16 #include <sys/ipc.h>
  17 #include <stdint.h>
  18 #include <stddef.h>
  19 #include <inttypes.h>
  20 #include <time.h>
  21 #include <stdbool.h>
  22 #include <unistd.h>
  23 #include <dlfcn.h>
  24 #include <lttng/ust-endian.h>
  25
  26 #include <urcu/arch.h>
  27 #include <urcu/compiler.h>
  28 #include <urcu/hlist.h>
  29 #include <urcu/list.h>
  30 #include <urcu/uatomic.h>
  31
  32 #include <lttng/tracepoint.h>
  33 #include <lttng/ust-events.h>
  34
  35 #include "common/logging.h"
  36 #include "common/macros.h"
  37 #include <lttng/ust-ctl.h>
  38 #include "common/ustcomm.h"
  39 #include "common/ust-fd.h"
  40 #include "common/dynamic-type.h"
  41 #include "common/ust-context-provider.h"
  42 #include "lttng-ust-uuid.h"
  43
  44 #include "common/tracepoint.h"
  45 #include "common/strutils.h"
  46 #include "lttng-bytecode.h"
  47 #include "lttng-tracer.h"
  48 #include "lttng-tracer-core.h"
  49 #include "lttng-ust-statedump.h"
  50 #include "context-internal.h"
  51 #include "lib/lttng-ust/events.h"
  52 #include "wait.h"
  53 #include "common/ringbuffer/shm.h"
  54 #include "common/ringbuffer/frontend_types.h"
  55 #include "common/ringbuffer/frontend.h"
  56 #include "common/counter/counter.h"
  57 #include "common/jhash.h"
  58 #include <lttng/ust-abi.h>
  59 #include "context-provider-internal.h"
  60
  61 /*
  62  * All operations within this file are called by the communication
  63  * thread, under ust_lock protection.
  64  */
  65
  66 static CDS_LIST_HEAD(sessions);
  67 static CDS_LIST_HEAD(event_notifier_groups);
  68
  69 struct cds_list_head *lttng_get_sessions(void)
  70 {
  71         return &sessions;
  72 }
  73
  74 static void _lttng_event_destroy(struct lttng_ust_event_common *event);
  75 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  76
  77 static
  78 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session);
  79 static
  80 void lttng_session_sync_event_enablers(struct lttng_ust_session *session);
  81 static
  82 void lttng_event_notifier_group_sync_enablers(
  83                 struct lttng_event_notifier_group *event_notifier_group);
  84 static
  85 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  86
  87 bool lttng_ust_validate_event_name(const struct lttng_ust_event_desc *desc)
  88 {
  89         if (strlen(desc->probe_desc->provider_name) + 1 +
  90                         strlen(desc->event_name) >= LTTNG_UST_ABI_SYM_NAME_LEN)
  91                 return false;
  92         return true;
  93 }
  94
  95 void lttng_ust_format_event_name(const struct lttng_ust_event_desc *desc,
  96                 char *name)
  97 {
  98         strcpy(name, desc->probe_desc->provider_name);
  99         strcat(name, ":");
 100         strcat(name, desc->event_name);
 101 }
 102
 103 /*
 104  * Called with ust lock held.
 105  */
 106 int lttng_session_active(void)
 107 {
 108         struct lttng_ust_session_private *iter;
 109
 110         cds_list_for_each_entry(iter, &sessions, node) {
 111                 if (iter->pub->active)
 112                         return 1;
 113         }
 114         return 0;
 115 }
 116
 117 static
 118 int lttng_loglevel_match(int loglevel,
 119                 unsigned int has_loglevel,
 120                 enum lttng_ust_abi_loglevel_type req_type,
 121                 int req_loglevel)
 122 {
 123         if (!has_loglevel)
 124                 loglevel = TRACE_DEFAULT;
 125         switch (req_type) {
 126         case LTTNG_UST_ABI_LOGLEVEL_RANGE:
 127                 if (loglevel <= req_loglevel
 128                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 129                         return 1;
 130                 else
 131                         return 0;
 132         case LTTNG_UST_ABI_LOGLEVEL_SINGLE:
 133                 if (loglevel == req_loglevel
 134                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 135                         return 1;
 136                 else
 137                         return 0;
 138         case LTTNG_UST_ABI_LOGLEVEL_ALL:
 139         default:
 140                 if (loglevel <= TRACE_DEBUG)
 141                         return 1;
 142                 else
 143                         return 0;
 144         }
 145 }
 146
 147 struct lttng_ust_session *lttng_session_create(void)
 148 {
 149         struct lttng_ust_session *session;
 150         struct lttng_ust_session_private *session_priv;
 151         int i;
 152
 153         session = zmalloc(sizeof(struct lttng_ust_session));
 154         if (!session)
 155                 return NULL;
 156         session->struct_size = sizeof(struct lttng_ust_session);
 157         session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
 158         if (!session_priv) {
 159                 free(session);
 160                 return NULL;
 161         }
 162         session->priv = session_priv;
 163         session_priv->pub = session;
 164         if (lttng_context_init_all(&session->priv->ctx)) {
 165                 free(session_priv);
 166                 free(session);
 167                 return NULL;
 168         }
 169         CDS_INIT_LIST_HEAD(&session->priv->chan_head);
 170         CDS_INIT_LIST_HEAD(&session->priv->events_head);
 171         CDS_INIT_LIST_HEAD(&session->priv->enums_head);
 172         CDS_INIT_LIST_HEAD(&session->priv->enablers_head);
 173         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 174                 CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 175         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 176                 CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
 177         cds_list_add(&session->priv->node, &sessions);
 178         return session;
 179 }
 180
 181 struct lttng_counter *lttng_ust_counter_create(
 182                 const char *counter_transport_name,
 183                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 184 {
 185         struct lttng_counter_transport *counter_transport = NULL;
 186         struct lttng_counter *counter = NULL;
 187
 188         counter_transport = lttng_counter_transport_find(counter_transport_name);
 189         if (!counter_transport)
 190                 goto notransport;
 191         counter = zmalloc(sizeof(struct lttng_counter));
 192         if (!counter)
 193                 goto nomem;
 194
 195         counter->ops = &counter_transport->ops;
 196         counter->transport = counter_transport;
 197
 198         counter->counter = counter->ops->counter_create(
 199                         number_dimensions, dimensions, 0,
 200                         -1, 0, NULL, false);
 201         if (!counter->counter) {
 202                 goto create_error;
 203         }
 204
 205         return counter;
 206
 207 create_error:
 208         free(counter);
 209 nomem:
 210 notransport:
 211         return NULL;
 212 }
 213
 214 static
 215 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 216 {
 217         counter->ops->counter_destroy(counter->counter);
 218         free(counter);
 219 }
 220
 221 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 222 {
 223         struct lttng_event_notifier_group *event_notifier_group;
 224         int i;
 225
 226         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 227         if (!event_notifier_group)
 228                 return NULL;
 229
 230         /* Add all contexts. */
 231         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 232                 free(event_notifier_group);
 233                 return NULL;
 234         }
 235
 236         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 237         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 238         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 239                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 240
 241         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 242
 243         return event_notifier_group;
 244 }
 245
 246 /*
 247  * Only used internally at session destruction.
 248  */
 249 static
 250 void _lttng_channel_unmap(struct lttng_ust_channel_buffer *lttng_chan)
 251 {
 252         struct lttng_ust_lib_ring_buffer_channel *chan;
 253         struct lttng_ust_shm_handle *handle;
 254
 255         cds_list_del(&lttng_chan->priv->node);
 256         lttng_destroy_context(lttng_chan->priv->ctx);
 257         chan = lttng_chan->priv->rb_chan;
 258         handle = chan->handle;
 259         channel_destroy(chan, handle, 0);
 260         free(lttng_chan->parent);
 261         free(lttng_chan->priv);
 262         free(lttng_chan);
 263 }
 264
 265 static
 266 void register_event(struct lttng_ust_event_common *event)
 267 {
 268         int ret;
 269         const struct lttng_ust_event_desc *desc;
 270         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 271
 272         assert(event->priv->registered == 0);
 273         desc = event->priv->desc;
 274         lttng_ust_format_event_name(desc, name);
 275         ret = lttng_ust_tp_probe_register_queue_release(name,
 276                         desc->probe_callback,
 277                         event, desc->signature);
 278         WARN_ON_ONCE(ret);
 279         if (!ret)
 280                 event->priv->registered = 1;
 281 }
 282
 283 static
 284 void unregister_event(struct lttng_ust_event_common *event)
 285 {
 286         int ret;
 287         const struct lttng_ust_event_desc *desc;
 288         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 289
 290         assert(event->priv->registered == 1);
 291         desc = event->priv->desc;
 292         lttng_ust_format_event_name(desc, name);
 293         ret = lttng_ust_tp_probe_unregister_queue_release(name,
 294                         desc->probe_callback,
 295                         event);
 296         WARN_ON_ONCE(ret);
 297         if (!ret)
 298                 event->priv->registered = 0;
 299 }
 300
 301 static
 302 void _lttng_event_unregister(struct lttng_ust_event_common *event)
 303 {
 304         if (event->priv->registered)
 305                 unregister_event(event);
 306 }
 307
 308 void lttng_session_destroy(struct lttng_ust_session *session)
 309 {
 310         struct lttng_ust_channel_buffer_private *chan, *tmpchan;
 311         struct lttng_ust_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
 312         struct lttng_enum *_enum, *tmp_enum;
 313         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 314
 315         CMM_ACCESS_ONCE(session->active) = 0;
 316         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
 317                 _lttng_event_unregister(event_recorder_priv->parent.pub);
 318         }
 319         lttng_ust_urcu_synchronize_rcu();       /* Wait for in-flight events to complete */
 320         lttng_ust_tp_probe_prune_release_queue();
 321         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 322                         &session->priv->enablers_head, node)
 323                 lttng_event_enabler_destroy(event_enabler);
 324         cds_list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv,
 325                         &session->priv->events_head, node)
 326                 _lttng_event_destroy(event_recorder_priv->parent.pub);
 327         cds_list_for_each_entry_safe(_enum, tmp_enum,
 328                         &session->priv->enums_head, node)
 329                 _lttng_enum_destroy(_enum);
 330         cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 331                 _lttng_channel_unmap(chan->pub);
 332         cds_list_del(&session->priv->node);
 333         lttng_destroy_context(session->priv->ctx);
 334         free(session->priv);
 335         free(session);
 336 }
 337
 338 void lttng_event_notifier_group_destroy(
 339                 struct lttng_event_notifier_group *event_notifier_group)
 340 {
 341         int close_ret;
 342         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 343         struct lttng_ust_event_notifier_private *event_notifier_priv, *tmpevent_notifier_priv;
 344
 345         if (!event_notifier_group) {
 346                 return;
 347         }
 348
 349         cds_list_for_each_entry(event_notifier_priv,
 350                         &event_notifier_group->event_notifiers_head, node)
 351                 _lttng_event_unregister(event_notifier_priv->parent.pub);
 352
 353         lttng_ust_urcu_synchronize_rcu();
 354
 355         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 356                         &event_notifier_group->enablers_head, node)
 357                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 358
 359         cds_list_for_each_entry_safe(event_notifier_priv, tmpevent_notifier_priv,
 360                         &event_notifier_group->event_notifiers_head, node)
 361                 _lttng_event_destroy(event_notifier_priv->parent.pub);
 362
 363         if (event_notifier_group->error_counter)
 364                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 365
 366         /* Close the notification fd to the listener of event_notifiers. */
 367
 368         lttng_ust_lock_fd_tracker();
 369         close_ret = close(event_notifier_group->notification_fd);
 370         if (!close_ret) {
 371                 lttng_ust_delete_fd_from_tracker(
 372                                 event_notifier_group->notification_fd);
 373         } else {
 374                 PERROR("close");
 375                 abort();
 376         }
 377         lttng_ust_unlock_fd_tracker();
 378
 379         cds_list_del(&event_notifier_group->node);
 380         lttng_destroy_context(event_notifier_group->ctx);
 381         free(event_notifier_group);
 382 }
 383
 384 static
 385 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 386 {
 387         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 388         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 389
 390         if (!enabler) {
 391                 return;
 392         }
 393
 394         /* Destroy filter bytecode */
 395         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 396                         &enabler->filter_bytecode_head, node) {
 397                 free(filter_node);
 398         }
 399
 400         /* Destroy excluders */
 401         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 402                         &enabler->excluder_head, node) {
 403                 free(excluder_node);
 404         }
 405 }
 406
 407  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 408 {
 409         if (!event_notifier_enabler) {
 410                 return;
 411         }
 412
 413         cds_list_del(&event_notifier_enabler->node);
 414
 415         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 416
 417         free(event_notifier_enabler);
 418 }
 419
 420 static
 421 int lttng_enum_create(const struct lttng_ust_enum_desc *desc,
 422                 struct lttng_ust_session *session)
 423 {
 424         const char *enum_name = desc->name;
 425         struct lttng_enum *_enum;
 426         struct cds_hlist_head *head;
 427         int ret = 0;
 428         size_t name_len = strlen(enum_name);
 429         uint32_t hash;
 430         int notify_socket;
 431
 432         /* Check if this enum is already registered for this session. */
 433         hash = jhash(enum_name, name_len, 0);
 434         head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 435
 436         _enum = lttng_ust_enum_get_from_desc(session, desc);
 437         if (_enum) {
 438                 ret = -EEXIST;
 439                 goto exist;
 440         }
 441
 442         notify_socket = lttng_get_notify_socket(session->priv->owner);
 443         if (notify_socket < 0) {
 444                 ret = notify_socket;
 445                 goto socket_error;
 446         }
 447
 448         _enum = zmalloc(sizeof(*_enum));
 449         if (!_enum) {
 450                 ret = -ENOMEM;
 451                 goto cache_error;
 452         }
 453         _enum->session = session;
 454         _enum->desc = desc;
 455
 456         ret = ustcomm_register_enum(notify_socket,
 457                 session->priv->objd,
 458                 enum_name,
 459                 desc->nr_entries,
 460                 desc->entries,
 461                 &_enum->id);
 462         if (ret < 0) {
 463                 DBG("Error (%d) registering enumeration to sessiond", ret);
 464                 goto sessiond_register_error;
 465         }
 466         cds_list_add(&_enum->node, &session->priv->enums_head);
 467         cds_hlist_add_head(&_enum->hlist, head);
 468         return 0;
 469
 470 sessiond_register_error:
 471         free(_enum);
 472 cache_error:
 473 socket_error:
 474 exist:
 475         return ret;
 476 }
 477
 478 static
 479 int lttng_create_enum_check(const struct lttng_ust_type_common *type,
 480                 struct lttng_ust_session *session)
 481 {
 482         switch (type->type) {
 483         case lttng_ust_type_enum:
 484         {
 485                 const struct lttng_ust_enum_desc *enum_desc;
 486                 int ret;
 487
 488                 enum_desc = lttng_ust_get_type_enum(type)->desc;
 489                 ret = lttng_enum_create(enum_desc, session);
 490                 if (ret && ret != -EEXIST) {
 491                         DBG("Unable to create enum error: (%d)", ret);
 492                         return ret;
 493                 }
 494                 break;
 495         }
 496         case lttng_ust_type_dynamic:
 497         {
 498                 const struct lttng_ust_event_field *tag_field_generic;
 499                 const struct lttng_ust_enum_desc *enum_desc;
 500                 int ret;
 501
 502                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 503                 enum_desc = lttng_ust_get_type_enum(tag_field_generic->type)->desc;
 504                 ret = lttng_enum_create(enum_desc, session);
 505                 if (ret && ret != -EEXIST) {
 506                         DBG("Unable to create enum error: (%d)", ret);
 507                         return ret;
 508                 }
 509                 break;
 510         }
 511         default:
 512                 /* TODO: nested types when they become supported. */
 513                 break;
 514         }
 515         return 0;
 516 }
 517
 518 static
 519 int lttng_create_all_event_enums(size_t nr_fields,
 520                 const struct lttng_ust_event_field **event_fields,
 521                 struct lttng_ust_session *session)
 522 {
 523         size_t i;
 524         int ret;
 525
 526         /* For each field, ensure enum is part of the session. */
 527         for (i = 0; i < nr_fields; i++) {
 528                 const struct lttng_ust_type_common *type = event_fields[i]->type;
 529
 530                 ret = lttng_create_enum_check(type, session);
 531                 if (ret)
 532                         return ret;
 533         }
 534         return 0;
 535 }
 536
 537 static
 538 int lttng_create_all_ctx_enums(size_t nr_fields,
 539                 struct lttng_ust_ctx_field *ctx_fields,
 540                 struct lttng_ust_session *session)
 541 {
 542         size_t i;
 543         int ret;
 544
 545         /* For each field, ensure enum is part of the session. */
 546         for (i = 0; i < nr_fields; i++) {
 547                 const struct lttng_ust_type_common *type = ctx_fields[i].event_field->type;
 548
 549                 ret = lttng_create_enum_check(type, session);
 550                 if (ret)
 551                         return ret;
 552         }
 553         return 0;
 554 }
 555
 556 /*
 557  * Ensure that a state-dump will be performed for this session at the end
 558  * of the current handle_message().
 559  */
 560 int lttng_session_statedump(struct lttng_ust_session *session)
 561 {
 562         session->priv->statedump_pending = 1;
 563         lttng_ust_sockinfo_session_enabled(session->priv->owner);
 564         return 0;
 565 }
 566
 567 int lttng_session_enable(struct lttng_ust_session *session)
 568 {
 569         int ret = 0;
 570         struct lttng_ust_channel_buffer_private *chan;
 571         int notify_socket;
 572
 573         if (session->active) {
 574                 ret = -EBUSY;
 575                 goto end;
 576         }
 577
 578         notify_socket = lttng_get_notify_socket(session->priv->owner);
 579         if (notify_socket < 0)
 580                 return notify_socket;
 581
 582         /* Set transient enabler state to "enabled" */
 583         session->priv->tstate = 1;
 584
 585         /* We need to sync enablers with session before activation. */
 586         lttng_session_sync_event_enablers(session);
 587
 588         /*
 589          * Snapshot the number of events per channel to know the type of header
 590          * we need to use.
 591          */
 592         cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 593                 struct lttng_ust_ctx *ctx;
 594                 struct lttng_ust_ctx_field *fields = NULL;
 595                 size_t nr_fields = 0;
 596                 uint32_t chan_id;
 597
 598                 /* don't change it if session stop/restart */
 599                 if (chan->header_type)
 600                         continue;
 601                 ctx = chan->ctx;
 602                 if (ctx) {
 603                         nr_fields = ctx->nr_fields;
 604                         fields = ctx->fields;
 605                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 606                                 session);
 607                         if (ret < 0) {
 608                                 DBG("Error (%d) adding enum to session", ret);
 609                                 return ret;
 610                         }
 611                 }
 612                 ret = ustcomm_register_channel(notify_socket,
 613                         session,
 614                         session->priv->objd,
 615                         chan->parent.objd,
 616                         nr_fields,
 617                         fields,
 618                         &chan_id,
 619                         &chan->header_type);
 620                 if (ret) {
 621                         DBG("Error (%d) registering channel to sessiond", ret);
 622                         return ret;
 623                 }
 624                 if (chan_id != chan->id) {
 625                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 626                                 chan_id, chan->id);
 627                         return -EINVAL;
 628                 }
 629         }
 630
 631         /* Set atomically the state to "active" */
 632         CMM_ACCESS_ONCE(session->active) = 1;
 633         CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 634
 635         ret = lttng_session_statedump(session);
 636         if (ret)
 637                 return ret;
 638 end:
 639         return ret;
 640 }
 641
 642 int lttng_session_disable(struct lttng_ust_session *session)
 643 {
 644         int ret = 0;
 645
 646         if (!session->active) {
 647                 ret = -EBUSY;
 648                 goto end;
 649         }
 650         /* Set atomically the state to "inactive" */
 651         CMM_ACCESS_ONCE(session->active) = 0;
 652
 653         /* Set transient enabler state to "disabled" */
 654         session->priv->tstate = 0;
 655         lttng_session_sync_event_enablers(session);
 656 end:
 657         return ret;
 658 }
 659
 660 int lttng_channel_enable(struct lttng_ust_channel_common *lttng_channel)
 661 {
 662         int ret = 0;
 663
 664         if (lttng_channel->enabled) {
 665                 ret = -EBUSY;
 666                 goto end;
 667         }
 668         /* Set transient enabler state to "enabled" */
 669         lttng_channel->priv->tstate = 1;
 670         lttng_session_sync_event_enablers(lttng_channel->session);
 671         /* Set atomically the state to "enabled" */
 672         CMM_ACCESS_ONCE(lttng_channel->enabled) = 1;
 673 end:
 674         return ret;
 675 }
 676
 677 int lttng_channel_disable(struct lttng_ust_channel_common *lttng_channel)
 678 {
 679         int ret = 0;
 680
 681         if (!lttng_channel->enabled) {
 682                 ret = -EBUSY;
 683                 goto end;
 684         }
 685         /* Set atomically the state to "disabled" */
 686         CMM_ACCESS_ONCE(lttng_channel->enabled) = 0;
 687         /* Set transient enabler state to "enabled" */
 688         lttng_channel->priv->tstate = 0;
 689         lttng_session_sync_event_enablers(lttng_channel->session);
 690 end:
 691         return ret;
 692 }
 693
 694 static inline
 695 struct cds_hlist_head *borrow_hash_table_bucket(
 696                 struct cds_hlist_head *hash_table,
 697                 unsigned int hash_table_size,
 698                 const struct lttng_ust_event_desc *desc)
 699 {
 700         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 701         size_t name_len;
 702         uint32_t hash;
 703
 704         lttng_ust_format_event_name(desc, name);
 705         name_len = strlen(name);
 706
 707         hash = jhash(name, name_len, 0);
 708         return &hash_table[hash & (hash_table_size - 1)];
 709 }
 710
 711 /*
 712  * Supports event creation while tracing session is active.
 713  */
 714 static
 715 int lttng_event_recorder_create(const struct lttng_ust_event_desc *desc,
 716                 struct lttng_ust_channel_buffer *chan)
 717 {
 718         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 719         struct lttng_ust_event_recorder *event_recorder;
 720         struct lttng_ust_event_recorder_private *event_recorder_priv;
 721         struct lttng_ust_session *session = chan->parent->session;
 722         struct cds_hlist_head *head;
 723         int ret = 0;
 724         int notify_socket, loglevel;
 725         const char *uri;
 726
 727         head = borrow_hash_table_bucket(chan->parent->session->priv->events_ht.table,
 728                 LTTNG_UST_EVENT_HT_SIZE, desc);
 729
 730         notify_socket = lttng_get_notify_socket(session->priv->owner);
 731         if (notify_socket < 0) {
 732                 ret = notify_socket;
 733                 goto socket_error;
 734         }
 735
 736         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 737                         session);
 738         if (ret < 0) {
 739                 DBG("Error (%d) adding enum to session", ret);
 740                 goto create_enum_error;
 741         }
 742
 743         /*
 744          * Check if loglevel match. Refuse to connect event if not.
 745          */
 746         event_recorder = zmalloc(sizeof(struct lttng_ust_event_recorder));
 747         if (!event_recorder) {
 748                 ret = -ENOMEM;
 749                 goto cache_error;
 750         }
 751         event_recorder->struct_size = sizeof(struct lttng_ust_event_recorder);
 752
 753         event_recorder->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 754         if (!event_recorder->parent) {
 755                 ret = -ENOMEM;
 756                 goto parent_error;
 757         }
 758         event_recorder->parent->struct_size = sizeof(struct lttng_ust_event_common);
 759         event_recorder->parent->type = LTTNG_UST_EVENT_TYPE_RECORDER;
 760         event_recorder->parent->child = event_recorder;
 761
 762         event_recorder_priv = zmalloc(sizeof(struct lttng_ust_event_recorder_private));
 763         if (!event_recorder_priv) {
 764                 ret = -ENOMEM;
 765                 goto priv_error;
 766         }
 767         event_recorder->priv = event_recorder_priv;
 768         event_recorder_priv->pub = event_recorder;
 769         event_recorder->parent->priv = &event_recorder_priv->parent;
 770         event_recorder_priv->parent.pub = event_recorder->parent;
 771
 772         event_recorder->chan = chan;
 773
 774         /* Event will be enabled by enabler sync. */
 775         event_recorder->parent->run_filter = lttng_ust_interpret_event_filter;
 776         event_recorder->parent->enabled = 0;
 777         event_recorder->parent->priv->registered = 0;
 778         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->filter_bytecode_runtime_head);
 779         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 780         event_recorder->parent->priv->desc = desc;
 781
 782         if (desc->loglevel)
 783                 loglevel = *(*desc->loglevel);
 784         else
 785                 loglevel = TRACE_DEFAULT;
 786         if (desc->model_emf_uri)
 787                 uri = *(desc->model_emf_uri);
 788         else
 789                 uri = NULL;
 790
 791         lttng_ust_format_event_name(desc, name);
 792
 793         /* Fetch event ID from sessiond */
 794         ret = ustcomm_register_event(notify_socket,
 795                 session,
 796                 session->priv->objd,
 797                 chan->priv->parent.objd,
 798                 name,
 799                 loglevel,
 800                 desc->signature,
 801                 desc->nr_fields,
 802                 desc->fields,
 803                 uri,
 804                 &event_recorder->priv->id);
 805         if (ret < 0) {
 806                 DBG("Error (%d) registering event to sessiond", ret);
 807                 goto sessiond_register_error;
 808         }
 809
 810         cds_list_add(&event_recorder_priv->node, &chan->parent->session->priv->events_head);
 811         cds_hlist_add_head(&event_recorder_priv->hlist, head);
 812         return 0;
 813
 814 sessiond_register_error:
 815         free(event_recorder_priv);
 816 priv_error:
 817         free(event_recorder->parent);
 818 parent_error:
 819         free(event_recorder);
 820 cache_error:
 821 create_enum_error:
 822 socket_error:
 823         return ret;
 824 }
 825
 826 static
 827 int lttng_event_notifier_create(const struct lttng_ust_event_desc *desc,
 828                 uint64_t token, uint64_t error_counter_index,
 829                 struct lttng_event_notifier_group *event_notifier_group)
 830 {
 831         struct lttng_ust_event_notifier *event_notifier;
 832         struct lttng_ust_event_notifier_private *event_notifier_priv;
 833         struct cds_hlist_head *head;
 834         int ret = 0;
 835
 836         /*
 837          * Get the hashtable bucket the created lttng_event_notifier object
 838          * should be inserted.
 839          */
 840         head = borrow_hash_table_bucket(
 841                 event_notifier_group->event_notifiers_ht.table,
 842                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 843
 844         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 845         if (!event_notifier) {
 846                 ret = -ENOMEM;
 847                 goto error;
 848         }
 849         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 850
 851         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 852         if (!event_notifier->parent) {
 853                 ret = -ENOMEM;
 854                 goto parent_error;
 855         }
 856         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 857         event_notifier->parent->type = LTTNG_UST_EVENT_TYPE_NOTIFIER;
 858         event_notifier->parent->child = event_notifier;
 859
 860         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 861         if (!event_notifier_priv) {
 862                 ret = -ENOMEM;
 863                 goto priv_error;
 864         }
 865         event_notifier->priv = event_notifier_priv;
 866         event_notifier_priv->pub = event_notifier;
 867         event_notifier->parent->priv = &event_notifier_priv->parent;
 868         event_notifier_priv->parent.pub = event_notifier->parent;
 869
 870         event_notifier_priv->group = event_notifier_group;
 871         event_notifier_priv->parent.user_token = token;
 872         event_notifier_priv->error_counter_index = error_counter_index;
 873
 874         /* Event notifier will be enabled by enabler sync. */
 875         event_notifier->parent->run_filter = lttng_ust_interpret_event_filter;
 876         event_notifier->parent->enabled = 0;
 877         event_notifier_priv->parent.registered = 0;
 878
 879         CDS_INIT_LIST_HEAD(&event_notifier->parent->priv->filter_bytecode_runtime_head);
 880         CDS_INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
 881         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 882         event_notifier_priv->parent.desc = desc;
 883         event_notifier->notification_send = lttng_event_notifier_notification_send;
 884
 885         cds_list_add(&event_notifier_priv->node,
 886                         &event_notifier_group->event_notifiers_head);
 887         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 888
 889         return 0;
 890
 891 priv_error:
 892         free(event_notifier->parent);
 893 parent_error:
 894         free(event_notifier);
 895 error:
 896         return ret;
 897 }
 898
 899 static
 900 int lttng_desc_match_star_glob_enabler(const struct lttng_ust_event_desc *desc,
 901                 struct lttng_enabler *enabler)
 902 {
 903         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 904         int loglevel = 0;
 905         unsigned int has_loglevel = 0;
 906
 907         lttng_ust_format_event_name(desc, name);
 908         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 909         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 910                         name, SIZE_MAX))
 911                 return 0;
 912         if (desc->loglevel) {
 913                 loglevel = *(*desc->loglevel);
 914                 has_loglevel = 1;
 915         }
 916         if (!lttng_loglevel_match(loglevel,
 917                         has_loglevel,
 918                         enabler->event_param.loglevel_type,
 919                         enabler->event_param.loglevel))
 920                 return 0;
 921         return 1;
 922 }
 923
 924 static
 925 int lttng_desc_match_event_enabler(const struct lttng_ust_event_desc *desc,
 926                 struct lttng_enabler *enabler)
 927 {
 928         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 929         int loglevel = 0;
 930         unsigned int has_loglevel = 0;
 931
 932         lttng_ust_format_event_name(desc, name);
 933         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 934         if (strcmp(name, enabler->event_param.name))
 935                 return 0;
 936         if (desc->loglevel) {
 937                 loglevel = *(*desc->loglevel);
 938                 has_loglevel = 1;
 939         }
 940         if (!lttng_loglevel_match(loglevel,
 941                         has_loglevel,
 942                         enabler->event_param.loglevel_type,
 943                         enabler->event_param.loglevel))
 944                 return 0;
 945         return 1;
 946 }
 947
 948 static
 949 int lttng_desc_match_enabler(const struct lttng_ust_event_desc *desc,
 950                 struct lttng_enabler *enabler)
 951 {
 952         switch (enabler->format_type) {
 953         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 954         {
 955                 struct lttng_ust_excluder_node *excluder;
 956
 957                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 958                         return 0;
 959                 }
 960
 961                 /*
 962                  * If the matching event matches with an excluder,
 963                  * return 'does not match'
 964                  */
 965                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 966                         int count;
 967
 968                         for (count = 0; count < excluder->excluder.count; count++) {
 969                                 int len;
 970                                 char *excluder_name;
 971
 972                                 excluder_name = (char *) (excluder->excluder.names)
 973                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
 974                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 975                                 if (len > 0) {
 976                                         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 977
 978                                         lttng_ust_format_event_name(desc, name);
 979                                         if (strutils_star_glob_match(excluder_name, len, name, SIZE_MAX)) {
 980                                                 return 0;
 981                                         }
 982                                 }
 983                         }
 984                 }
 985                 return 1;
 986         }
 987         case LTTNG_ENABLER_FORMAT_EVENT:
 988                 return lttng_desc_match_event_enabler(desc, enabler);
 989         default:
 990                 return -EINVAL;
 991         }
 992 }
 993
 994 static
 995 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 996                 struct lttng_ust_event_recorder *event_recorder)
 997 {
 998         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
 999                         lttng_event_enabler_as_enabler(event_enabler))
1000                         && event_recorder->chan == event_enabler->chan)
1001                 return 1;
1002         else
1003                 return 0;
1004 }
1005
1006 static
1007 int lttng_event_notifier_enabler_match_event_notifier(
1008                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1009                 struct lttng_ust_event_notifier *event_notifier)
1010 {
1011         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
1012                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1013
1014         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
1015                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
1016                 return 1;
1017         else
1018                 return 0;
1019 }
1020
1021 static
1022 struct lttng_enabler_ref *lttng_enabler_ref(
1023                 struct cds_list_head *enabler_ref_list,
1024                 struct lttng_enabler *enabler)
1025 {
1026         struct lttng_enabler_ref *enabler_ref;
1027
1028         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1029                 if (enabler_ref->ref == enabler)
1030                         return enabler_ref;
1031         }
1032         return NULL;
1033 }
1034
1035 /*
1036  * Create struct lttng_event if it is missing and present in the list of
1037  * tracepoint probes.
1038  */
1039 static
1040 void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_enabler)
1041 {
1042         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1043         struct lttng_ust_registered_probe *reg_probe;
1044         const struct lttng_ust_event_desc *desc;
1045         struct lttng_ust_event_recorder_private *event_recorder_priv;
1046         int i;
1047         struct cds_list_head *probe_list;
1048
1049         probe_list = lttng_get_probe_list_head();
1050         /*
1051          * For each probe event, if we find that a probe event matches
1052          * our enabler, create an associated lttng_event if not
1053          * already present.
1054          */
1055         cds_list_for_each_entry(reg_probe, probe_list, head) {
1056                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1057
1058                 for (i = 0; i < probe_desc->nr_events; i++) {
1059                         int ret;
1060                         bool found = false;
1061                         struct cds_hlist_head *head;
1062                         struct cds_hlist_node *node;
1063
1064                         desc = probe_desc->event_desc[i];
1065                         if (!lttng_desc_match_enabler(desc,
1066                                         lttng_event_enabler_as_enabler(event_enabler)))
1067                                 continue;
1068
1069                         head = borrow_hash_table_bucket(
1070                                 session->priv->events_ht.table,
1071                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1072
1073                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1074                                 if (event_recorder_priv->parent.desc == desc
1075                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1076                                         found = true;
1077                                         break;
1078                                 }
1079                         }
1080                         if (found)
1081                                 continue;
1082
1083                         /*
1084                          * We need to create an event for this
1085                          * event probe.
1086                          */
1087                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1088                                         event_enabler->chan);
1089                         if (ret) {
1090                                 DBG("Unable to create event \"%s:%s\", error %d\n",
1091                                         probe_desc->provider_name,
1092                                         probe_desc->event_desc[i]->event_name, ret);
1093                         }
1094                 }
1095         }
1096 }
1097
1098 static
1099 void probe_provider_event_for_each(const struct lttng_ust_probe_desc *provider_desc,
1100                 void (*event_func)(struct lttng_ust_event_common *event))
1101 {
1102         struct cds_hlist_node *node, *tmp_node;
1103         struct cds_list_head *sessionsp;
1104         unsigned int i;
1105
1106         /* Get handle on list of sessions. */
1107         sessionsp = lttng_get_sessions();
1108
1109         /*
1110          * Iterate over all events in the probe provider descriptions and
1111          * sessions to queue the unregistration of the events.
1112          */
1113         for (i = 0; i < provider_desc->nr_events; i++) {
1114                 const struct lttng_ust_event_desc *event_desc;
1115                 struct lttng_event_notifier_group *event_notifier_group;
1116                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1117                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1118                 struct lttng_ust_session_private *session_priv;
1119                 struct cds_hlist_head *head;
1120
1121                 event_desc = provider_desc->event_desc[i];
1122
1123                 /*
1124                  * Iterate over all session to find the current event
1125                  * description.
1126                  */
1127                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1128                         /*
1129                          * Get the list of events in the hashtable bucket and
1130                          * iterate to find the event matching this descriptor.
1131                          */
1132                         head = borrow_hash_table_bucket(
1133                                 session_priv->events_ht.table,
1134                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1135
1136                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1137                                 if (event_desc == event_recorder_priv->parent.desc) {
1138                                         event_func(event_recorder_priv->parent.pub);
1139                                         break;
1140                                 }
1141                         }
1142                 }
1143
1144                 /*
1145                  * Iterate over all event_notifier groups to find the current event
1146                  * description.
1147                  */
1148                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1149                         /*
1150                          * Get the list of event_notifiers in the hashtable bucket and
1151                          * iterate to find the event_notifier matching this
1152                          * descriptor.
1153                          */
1154                         head = borrow_hash_table_bucket(
1155                                 event_notifier_group->event_notifiers_ht.table,
1156                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1157
1158                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1159                                 if (event_desc == event_notifier_priv->parent.desc) {
1160                                         event_func(event_notifier_priv->parent.pub);
1161                                         break;
1162                                 }
1163                         }
1164                 }
1165         }
1166 }
1167
1168 static
1169 void _event_enum_destroy(struct lttng_ust_event_common *event)
1170 {
1171
1172         switch (event->type) {
1173         case LTTNG_UST_EVENT_TYPE_RECORDER:
1174         {
1175                 struct lttng_ust_event_recorder *event_recorder = event->child;
1176                 struct lttng_ust_session *session = event_recorder->chan->parent->session;
1177                 unsigned int i;
1178
1179                 /* Destroy enums of the current event. */
1180                 for (i = 0; i < event_recorder->parent->priv->desc->nr_fields; i++) {
1181                         const struct lttng_ust_enum_desc *enum_desc;
1182                         const struct lttng_ust_event_field *field;
1183                         struct lttng_enum *curr_enum;
1184
1185                         field = event_recorder->parent->priv->desc->fields[i];
1186                         switch (field->type->type) {
1187                         case lttng_ust_type_enum:
1188                                 enum_desc = lttng_ust_get_type_enum(field->type)->desc;
1189                                 break;
1190                         default:
1191                                 continue;
1192                         }
1193
1194                         curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1195                         if (curr_enum) {
1196                                 _lttng_enum_destroy(curr_enum);
1197                         }
1198                 }
1199                 break;
1200         }
1201         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1202                 break;
1203         default:
1204                 abort();
1205         }
1206         /* Destroy event. */
1207         _lttng_event_destroy(event);
1208 }
1209
1210 /*
1211  * Iterate over all the UST sessions to unregister and destroy all probes from
1212  * the probe provider descriptor received as argument. Must me called with the
1213  * ust_lock held.
1214  */
1215 void lttng_probe_provider_unregister_events(
1216                 const struct lttng_ust_probe_desc *provider_desc)
1217 {
1218         /*
1219          * Iterate over all events in the probe provider descriptions and sessions
1220          * to queue the unregistration of the events.
1221          */
1222         probe_provider_event_for_each(provider_desc, _lttng_event_unregister);
1223
1224         /* Wait for grace period. */
1225         lttng_ust_urcu_synchronize_rcu();
1226         /* Prune the unregistration queue. */
1227         lttng_ust_tp_probe_prune_release_queue();
1228
1229         /*
1230          * It is now safe to destroy the events and remove them from the event list
1231          * and hashtables.
1232          */
1233         probe_provider_event_for_each(provider_desc, _event_enum_destroy);
1234 }
1235
1236 /*
1237  * Create events associated with an event enabler (if not already present),
1238  * and add backward reference from the event to the enabler.
1239  */
1240 static
1241 int lttng_event_enabler_ref_event_recorders(struct lttng_event_enabler *event_enabler)
1242 {
1243         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1244         struct lttng_ust_event_recorder_private *event_recorder_priv;
1245
1246         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1247                 goto end;
1248
1249         /* First ensure that probe events are created for this enabler. */
1250         lttng_create_event_recorder_if_missing(event_enabler);
1251
1252         /* For each event matching enabler in session event list. */
1253         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1254                 struct lttng_enabler_ref *enabler_ref;
1255
1256                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1257                         continue;
1258
1259                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1260                         lttng_event_enabler_as_enabler(event_enabler));
1261                 if (!enabler_ref) {
1262                         /*
1263                          * If no backward ref, create it.
1264                          * Add backward ref from event to enabler.
1265                          */
1266                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1267                         if (!enabler_ref)
1268                                 return -ENOMEM;
1269                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1270                                 event_enabler);
1271                         cds_list_add(&enabler_ref->node,
1272                                 &event_recorder_priv->parent.enablers_ref_head);
1273                 }
1274
1275                 /*
1276                  * Link filter bytecodes if not linked yet.
1277                  */
1278                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1279                         &session->priv->ctx,
1280                         &event_recorder_priv->parent.filter_bytecode_runtime_head,
1281                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1282
1283                 /* TODO: merge event context. */
1284         }
1285 end:
1286         return 0;
1287 }
1288
1289 /*
1290  * Called at library load: connect the probe on all enablers matching
1291  * this event.
1292  * Called with session mutex held.
1293  */
1294 int lttng_fix_pending_events(void)
1295 {
1296         struct lttng_ust_session_private *session_priv;
1297
1298         cds_list_for_each_entry(session_priv, &sessions, node) {
1299                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1300         }
1301         return 0;
1302 }
1303
1304 int lttng_fix_pending_event_notifiers(void)
1305 {
1306         struct lttng_event_notifier_group *event_notifier_group;
1307
1308         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1309                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1310         }
1311         return 0;
1312 }
1313
1314 /*
1315  * For each session of the owner thread, execute pending statedump.
1316  * Only dump state for the sessions owned by the caller thread, because
1317  * we don't keep ust_lock across the entire iteration.
1318  */
1319 void lttng_handle_pending_statedump(void *owner)
1320 {
1321         struct lttng_ust_session_private *session_priv;
1322
1323         /* Execute state dump */
1324         do_lttng_ust_statedump(owner);
1325
1326         /* Clear pending state dump */
1327         if (ust_lock()) {
1328                 goto end;
1329         }
1330         cds_list_for_each_entry(session_priv, &sessions, node) {
1331                 if (session_priv->owner != owner)
1332                         continue;
1333                 if (!session_priv->statedump_pending)
1334                         continue;
1335                 session_priv->statedump_pending = 0;
1336         }
1337 end:
1338         ust_unlock();
1339         return;
1340 }
1341
1342 static
1343 void _lttng_event_destroy(struct lttng_ust_event_common *event)
1344 {
1345         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1346
1347         lttng_free_event_filter_runtime(event);
1348         /* Free event enabler refs */
1349         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1350                         &event->priv->enablers_ref_head, node)
1351                 free(enabler_ref);
1352
1353         switch (event->type) {
1354         case LTTNG_UST_EVENT_TYPE_RECORDER:
1355         {
1356                 struct lttng_ust_event_recorder *event_recorder = event->child;
1357
1358                 /* Remove from event list. */
1359                 cds_list_del(&event_recorder->priv->node);
1360                 /* Remove from event hash table. */
1361                 cds_hlist_del(&event_recorder->priv->hlist);
1362
1363                 lttng_destroy_context(event_recorder->priv->ctx);
1364                 free(event_recorder->parent);
1365                 free(event_recorder->priv);
1366                 free(event_recorder);
1367                 break;
1368         }
1369         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1370         {
1371                 struct lttng_ust_event_notifier *event_notifier = event->child;
1372
1373                 /* Remove from event list. */
1374                 cds_list_del(&event_notifier->priv->node);
1375                 /* Remove from event hash table. */
1376                 cds_hlist_del(&event_notifier->priv->hlist);
1377
1378                 free(event_notifier->priv);
1379                 free(event_notifier->parent);
1380                 free(event_notifier);
1381                 break;
1382         }
1383         default:
1384                 abort();
1385         }
1386 }
1387
1388 static
1389 void _lttng_enum_destroy(struct lttng_enum *_enum)
1390 {
1391         cds_list_del(&_enum->node);
1392         cds_hlist_del(&_enum->hlist);
1393         free(_enum);
1394 }
1395
1396 void lttng_ust_abi_events_exit(void)
1397 {
1398         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1399
1400         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1401                 lttng_session_destroy(session_priv->pub);
1402 }
1403
1404 /*
1405  * Enabler management.
1406  */
1407 struct lttng_event_enabler *lttng_event_enabler_create(
1408                 enum lttng_enabler_format_type format_type,
1409                 struct lttng_ust_abi_event *event_param,
1410                 struct lttng_ust_channel_buffer *chan)
1411 {
1412         struct lttng_event_enabler *event_enabler;
1413
1414         event_enabler = zmalloc(sizeof(*event_enabler));
1415         if (!event_enabler)
1416                 return NULL;
1417         event_enabler->base.format_type = format_type;
1418         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1419         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1420         memcpy(&event_enabler->base.event_param, event_param,
1421                 sizeof(event_enabler->base.event_param));
1422         event_enabler->chan = chan;
1423         /* ctx left NULL */
1424         event_enabler->base.enabled = 0;
1425         cds_list_add(&event_enabler->node, &event_enabler->chan->parent->session->priv->enablers_head);
1426         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1427
1428         return event_enabler;
1429 }
1430
1431 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1432                 struct lttng_event_notifier_group *event_notifier_group,
1433                 enum lttng_enabler_format_type format_type,
1434                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1435 {
1436         struct lttng_event_notifier_enabler *event_notifier_enabler;
1437
1438         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1439         if (!event_notifier_enabler)
1440                 return NULL;
1441         event_notifier_enabler->base.format_type = format_type;
1442         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1443         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1444         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1445
1446         event_notifier_enabler->user_token = event_notifier_param->event.token;
1447         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1448         event_notifier_enabler->num_captures = 0;
1449
1450         memcpy(&event_notifier_enabler->base.event_param.name,
1451                 event_notifier_param->event.name,
1452                 sizeof(event_notifier_enabler->base.event_param.name));
1453         event_notifier_enabler->base.event_param.instrumentation =
1454                 event_notifier_param->event.instrumentation;
1455         event_notifier_enabler->base.event_param.loglevel =
1456                 event_notifier_param->event.loglevel;
1457         event_notifier_enabler->base.event_param.loglevel_type =
1458                 event_notifier_param->event.loglevel_type;
1459
1460         event_notifier_enabler->base.enabled = 0;
1461         event_notifier_enabler->group = event_notifier_group;
1462
1463         cds_list_add(&event_notifier_enabler->node,
1464                         &event_notifier_group->enablers_head);
1465
1466         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1467
1468         return event_notifier_enabler;
1469 }
1470
1471 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1472 {
1473         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1474         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1475
1476         return 0;
1477 }
1478
1479 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1480 {
1481         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1482         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1483
1484         return 0;
1485 }
1486
1487 static
1488 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1489                 struct lttng_ust_bytecode_node **bytecode)
1490 {
1491         (*bytecode)->enabler = enabler;
1492         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1493         /* Take ownership of bytecode */
1494         *bytecode = NULL;
1495 }
1496
1497 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1498                 struct lttng_ust_bytecode_node **bytecode)
1499 {
1500         _lttng_enabler_attach_filter_bytecode(
1501                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1502
1503         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1504         return 0;
1505 }
1506
1507 static
1508 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1509                 struct lttng_ust_excluder_node **excluder)
1510 {
1511         (*excluder)->enabler = enabler;
1512         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1513         /* Take ownership of excluder */
1514         *excluder = NULL;
1515 }
1516
1517 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1518                 struct lttng_ust_excluder_node **excluder)
1519 {
1520         _lttng_enabler_attach_exclusion(
1521                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1522
1523         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1524         return 0;
1525 }
1526
1527 int lttng_event_notifier_enabler_enable(
1528                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1529 {
1530         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1531         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1532
1533         return 0;
1534 }
1535
1536 int lttng_event_notifier_enabler_disable(
1537                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1538 {
1539         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1540         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1541
1542         return 0;
1543 }
1544
1545 int lttng_event_notifier_enabler_attach_filter_bytecode(
1546                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1547                 struct lttng_ust_bytecode_node **bytecode)
1548 {
1549         _lttng_enabler_attach_filter_bytecode(
1550                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1551                 bytecode);
1552
1553         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1554         return 0;
1555 }
1556
1557 int lttng_event_notifier_enabler_attach_capture_bytecode(
1558                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1559                 struct lttng_ust_bytecode_node **bytecode)
1560 {
1561         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1562                         event_notifier_enabler);
1563         cds_list_add_tail(&(*bytecode)->node,
1564                         &event_notifier_enabler->capture_bytecode_head);
1565         /* Take ownership of bytecode */
1566         *bytecode = NULL;
1567         event_notifier_enabler->num_captures++;
1568
1569         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1570         return 0;
1571 }
1572
1573 int lttng_event_notifier_enabler_attach_exclusion(
1574                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1575                 struct lttng_ust_excluder_node **excluder)
1576 {
1577         _lttng_enabler_attach_exclusion(
1578                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1579                 excluder);
1580
1581         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1582         return 0;
1583 }
1584
1585 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1586                 union lttng_ust_abi_args *uargs,
1587                 struct lttng_ust_ctx **ctx, struct lttng_ust_session *session)
1588 {
1589         /*
1590          * We cannot attach a context after trace has been started for a
1591          * session because the metadata does not allow expressing this
1592          * information outside of the original channel scope.
1593          */
1594         if (session->priv->been_active)
1595                 return -EPERM;
1596
1597         switch (context_param->ctx) {
1598         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1599                 return lttng_add_pthread_id_to_ctx(ctx);
1600         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1601         {
1602                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1603
1604                 perf_ctx_param = &context_param->u.perf_counter;
1605                 return lttng_add_perf_counter_to_ctx(
1606                         perf_ctx_param->type,
1607                         perf_ctx_param->config,
1608                         perf_ctx_param->name,
1609                         ctx);
1610         }
1611         case LTTNG_UST_ABI_CONTEXT_VTID:
1612                 return lttng_add_vtid_to_ctx(ctx);
1613         case LTTNG_UST_ABI_CONTEXT_VPID:
1614                 return lttng_add_vpid_to_ctx(ctx);
1615         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1616                 return lttng_add_procname_to_ctx(ctx);
1617         case LTTNG_UST_ABI_CONTEXT_IP:
1618                 return lttng_add_ip_to_ctx(ctx);
1619         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1620                 return lttng_add_cpu_id_to_ctx(ctx);
1621         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1622                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1623                         ctx);
1624         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1625                 return lttng_add_cgroup_ns_to_ctx(ctx);
1626         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1627                 return lttng_add_ipc_ns_to_ctx(ctx);
1628         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1629                 return lttng_add_mnt_ns_to_ctx(ctx);
1630         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1631                 return lttng_add_net_ns_to_ctx(ctx);
1632         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1633                 return lttng_add_pid_ns_to_ctx(ctx);
1634         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1635                 return lttng_add_time_ns_to_ctx(ctx);
1636         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1637                 return lttng_add_user_ns_to_ctx(ctx);
1638         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1639                 return lttng_add_uts_ns_to_ctx(ctx);
1640         case LTTNG_UST_ABI_CONTEXT_VUID:
1641                 return lttng_add_vuid_to_ctx(ctx);
1642         case LTTNG_UST_ABI_CONTEXT_VEUID:
1643                 return lttng_add_veuid_to_ctx(ctx);
1644         case LTTNG_UST_ABI_CONTEXT_VSUID:
1645                 return lttng_add_vsuid_to_ctx(ctx);
1646         case LTTNG_UST_ABI_CONTEXT_VGID:
1647                 return lttng_add_vgid_to_ctx(ctx);
1648         case LTTNG_UST_ABI_CONTEXT_VEGID:
1649                 return lttng_add_vegid_to_ctx(ctx);
1650         case LTTNG_UST_ABI_CONTEXT_VSGID:
1651                 return lttng_add_vsgid_to_ctx(ctx);
1652         default:
1653                 return -EINVAL;
1654         }
1655 }
1656
1657 int lttng_event_enabler_attach_context(
1658                 struct lttng_event_enabler *enabler __attribute__((unused)),
1659                 struct lttng_ust_abi_context *context_param __attribute__((unused)))
1660 {
1661         return -ENOSYS;
1662 }
1663
1664 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1665 {
1666         if (!event_enabler) {
1667                 return;
1668         }
1669         cds_list_del(&event_enabler->node);
1670
1671         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1672
1673         lttng_destroy_context(event_enabler->ctx);
1674         free(event_enabler);
1675 }
1676
1677 /*
1678  * lttng_session_sync_event_enablers should be called just before starting a
1679  * session.
1680  */
1681 static
1682 void lttng_session_sync_event_enablers(struct lttng_ust_session *session)
1683 {
1684         struct lttng_event_enabler *event_enabler;
1685         struct lttng_ust_event_recorder_private *event_recorder_priv;
1686
1687         cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
1688                 lttng_event_enabler_ref_event_recorders(event_enabler);
1689         /*
1690          * For each event, if at least one of its enablers is enabled,
1691          * and its channel and session transient states are enabled, we
1692          * enable the event, else we disable it.
1693          */
1694         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1695                 struct lttng_enabler_ref *enabler_ref;
1696                 struct lttng_ust_bytecode_runtime *runtime;
1697                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1698                 int nr_filters = 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->priv->parent.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(event_recorder_priv->parent.pub);
1723                 } else {
1724                         if (event_recorder_priv->parent.registered)
1725                                 unregister_event(event_recorder_priv->parent.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_filter_bytecode = 1;
1734                                 break;
1735                         }
1736                 }
1737                 event_recorder_priv->parent.has_enablers_without_filter_bytecode =
1738                         has_enablers_without_filter_bytecode;
1739
1740                 /* Enable filters */
1741                 cds_list_for_each_entry(runtime,
1742                                 &event_recorder_priv->parent.filter_bytecode_runtime_head, node) {
1743                         lttng_bytecode_sync_state(runtime);
1744                         nr_filters++;
1745                 }
1746                 CMM_STORE_SHARED(event_recorder_priv->parent.pub->eval_filter,
1747                         !(has_enablers_without_filter_bytecode || !nr_filters));
1748         }
1749         lttng_ust_tp_probe_prune_release_queue();
1750 }
1751
1752 /* Support for event notifier is introduced by probe provider major version 2. */
1753 static
1754 bool lttng_ust_probe_supports_event_notifier(const struct lttng_ust_probe_desc *probe_desc)
1755 {
1756         return probe_desc->major >= 2;
1757 }
1758
1759 static
1760 void lttng_create_event_notifier_if_missing(
1761                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1762 {
1763         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1764         struct lttng_ust_registered_probe *reg_probe;
1765         struct cds_list_head *probe_list;
1766         int i;
1767
1768         probe_list = lttng_get_probe_list_head();
1769
1770         cds_list_for_each_entry(reg_probe, probe_list, head) {
1771                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1772
1773                 for (i = 0; i < probe_desc->nr_events; i++) {
1774                         int ret;
1775                         bool found = false;
1776                         const struct lttng_ust_event_desc *desc;
1777                         struct lttng_ust_event_notifier_private *event_notifier_priv;
1778                         struct cds_hlist_head *head;
1779                         struct cds_hlist_node *node;
1780
1781                         desc = probe_desc->event_desc[i];
1782
1783                         if (!lttng_desc_match_enabler(desc,
1784                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1785                                 continue;
1786
1787                         /*
1788                          * Given the current event_notifier group, get the bucket that
1789                          * the target event_notifier would be if it was already
1790                          * created.
1791                          */
1792                         head = borrow_hash_table_bucket(
1793                                 event_notifier_group->event_notifiers_ht.table,
1794                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1795
1796                         cds_hlist_for_each_entry(event_notifier_priv, node, head, hlist) {
1797                                 /*
1798                                  * Check if event_notifier already exists by checking
1799                                  * if the event_notifier and enabler share the same
1800                                  * description and id.
1801                                  */
1802                                 if (event_notifier_priv->parent.desc == desc &&
1803                                                 event_notifier_priv->parent.user_token == event_notifier_enabler->user_token) {
1804                                         found = true;
1805                                         break;
1806                                 }
1807                         }
1808
1809                         if (found)
1810                                 continue;
1811
1812                         /* Check that the probe supports event notifiers, else report the error. */
1813                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1814                                 ERR("Probe \"%s\" contains event \"%s:%s\" which matches an enabled event notifier, "
1815                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1816                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1817                                         "this event will not generate any notification.",
1818                                         probe_desc->provider_name,
1819                                         probe_desc->provider_name, desc->event_name,
1820                                         probe_desc->major,
1821                                         probe_desc->minor);
1822                                 continue;
1823                         }
1824                         /*
1825                          * We need to create a event_notifier for this event probe.
1826                          */
1827                         ret = lttng_event_notifier_create(desc,
1828                                 event_notifier_enabler->user_token,
1829                                 event_notifier_enabler->error_counter_index,
1830                                 event_notifier_group);
1831                         if (ret) {
1832                                 DBG("Unable to create event_notifier \"%s:%s\", error %d\n",
1833                                         probe_desc->provider_name,
1834                                         probe_desc->event_desc[i]->event_name, ret);
1835                         }
1836                 }
1837         }
1838 }
1839
1840 /*
1841  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1842  */
1843 static
1844 int lttng_event_notifier_enabler_ref_event_notifiers(
1845                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1846 {
1847         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1848         struct lttng_ust_event_notifier_private *event_notifier_priv;
1849
1850          /*
1851           * Only try to create event_notifiers for enablers that are enabled, the user
1852           * might still be attaching filter or exclusion to the
1853           * event_notifier_enabler.
1854           */
1855         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1856                 goto end;
1857
1858         /* First, ensure that probe event_notifiers are created for this enabler. */
1859         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1860
1861         /* Link the created event_notifier with its associated enabler. */
1862         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1863                 struct lttng_enabler_ref *enabler_ref;
1864
1865                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier_priv->pub))
1866                         continue;
1867
1868                 enabler_ref = lttng_enabler_ref(&event_notifier_priv->parent.enablers_ref_head,
1869                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1870                 if (!enabler_ref) {
1871                         /*
1872                          * If no backward ref, create it.
1873                          * Add backward ref from event_notifier to enabler.
1874                          */
1875                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1876                         if (!enabler_ref)
1877                                 return -ENOMEM;
1878
1879                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1880                                 event_notifier_enabler);
1881                         cds_list_add(&enabler_ref->node,
1882                                 &event_notifier_priv->parent.enablers_ref_head);
1883                 }
1884
1885                 /*
1886                  * Link filter bytecodes if not linked yet.
1887                  */
1888                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1889                         &event_notifier_group->ctx,
1890                         &event_notifier_priv->parent.filter_bytecode_runtime_head,
1891                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1892
1893                 /*
1894                  * Link capture bytecodes if not linked yet.
1895                  */
1896                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1897                         &event_notifier_group->ctx, &event_notifier_priv->capture_bytecode_runtime_head,
1898                         &event_notifier_enabler->capture_bytecode_head);
1899
1900                 event_notifier_priv->num_captures = event_notifier_enabler->num_captures;
1901         }
1902 end:
1903         return 0;
1904 }
1905
1906 static
1907 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1908 {
1909         struct lttng_event_notifier_enabler *event_notifier_enabler;
1910         struct lttng_ust_event_notifier_private *event_notifier_priv;
1911
1912         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1913                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1914
1915         /*
1916          * For each event_notifier, if at least one of its enablers is enabled,
1917          * we enable the event_notifier, else we disable it.
1918          */
1919         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1920                 struct lttng_enabler_ref *enabler_ref;
1921                 struct lttng_ust_bytecode_runtime *runtime;
1922                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1923                 int nr_filters = 0, nr_captures = 0;
1924
1925                 /* Enable event_notifiers */
1926                 cds_list_for_each_entry(enabler_ref,
1927                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1928                         if (enabler_ref->ref->enabled) {
1929                                 enabled = 1;
1930                                 break;
1931                         }
1932                 }
1933
1934                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1935                 /*
1936                  * Sync tracepoint registration with event_notifier enabled
1937                  * state.
1938                  */
1939                 if (enabled) {
1940                         if (!event_notifier_priv->parent.registered)
1941                                 register_event(event_notifier_priv->parent.pub);
1942                 } else {
1943                         if (event_notifier_priv->parent.registered)
1944                                 unregister_event(event_notifier_priv->parent.pub);
1945                 }
1946
1947                 /* Check if has enablers without bytecode enabled */
1948                 cds_list_for_each_entry(enabler_ref,
1949                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1950                         if (enabler_ref->ref->enabled
1951                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1952                                 has_enablers_without_filter_bytecode = 1;
1953                                 break;
1954                         }
1955                 }
1956                 event_notifier_priv->parent.has_enablers_without_filter_bytecode =
1957                         has_enablers_without_filter_bytecode;
1958
1959                 /* Enable filters */
1960                 cds_list_for_each_entry(runtime,
1961                                 &event_notifier_priv->parent.filter_bytecode_runtime_head, node) {
1962                         lttng_bytecode_sync_state(runtime);
1963                         nr_filters++;
1964                 }
1965                 CMM_STORE_SHARED(event_notifier_priv->parent.pub->eval_filter,
1966                         !(has_enablers_without_filter_bytecode || !nr_filters));
1967
1968                 /* Enable captures. */
1969                 cds_list_for_each_entry(runtime,
1970                                 &event_notifier_priv->capture_bytecode_runtime_head, node) {
1971                         lttng_bytecode_sync_state(runtime);
1972                         nr_captures++;
1973                 }
1974                 CMM_STORE_SHARED(event_notifier_priv->pub->eval_capture,
1975                                 !!nr_captures);
1976         }
1977         lttng_ust_tp_probe_prune_release_queue();
1978 }
1979
1980 /*
1981  * Apply enablers to session events, adding events to session if need
1982  * be. It is required after each modification applied to an active
1983  * session, and right before session "start".
1984  * "lazy" sync means we only sync if required.
1985  */
1986 static
1987 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session)
1988 {
1989         /* We can skip if session is not active */
1990         if (!session->active)
1991                 return;
1992         lttng_session_sync_event_enablers(session);
1993 }
1994
1995 /*
1996  * Update all sessions 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_session_provider(const char *name,
2003                 size_t (*get_size)(void *priv, size_t offset),
2004                 void (*record)(void *priv, struct lttng_ust_lib_ring_buffer_ctx *ctx,
2005                         struct lttng_ust_channel_buffer *chan),
2006                 void (*get_value)(void *priv, struct lttng_ust_ctx_value *value),
2007                 void *priv)
2008 {
2009         struct lttng_ust_session_private *session_priv;
2010
2011         cds_list_for_each_entry(session_priv, &sessions, node) {
2012                 struct lttng_ust_channel_buffer_private *chan;
2013                 struct lttng_ust_event_recorder_private *event_recorder_priv;
2014                 int ret;
2015
2016                 ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
2017                                 name, get_size, record, get_value, priv);
2018                 if (ret)
2019                         abort();
2020                 cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
2021                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
2022                                         name, get_size, record, get_value, priv);
2023                         if (ret)
2024                                 abort();
2025                 }
2026                 cds_list_for_each_entry(event_recorder_priv, &session_priv->events_head, node) {
2027                         ret = lttng_ust_context_set_provider_rcu(&event_recorder_priv->ctx,
2028                                         name, get_size, record, get_value, priv);
2029                         if (ret)
2030                                 abort();
2031                 }
2032         }
2033 }
2034
2035 /*
2036  * Update all event_notifier groups with the given app context.
2037  * Called with ust lock held.
2038  * This is invoked when an application context gets loaded/unloaded. It
2039  * ensures the context callbacks are in sync with the application
2040  * context (either app context callbacks, or dummy callbacks).
2041  */
2042 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
2043                 size_t (*get_size)(void *priv, size_t offset),
2044                 void (*record)(void *priv, struct lttng_ust_lib_ring_buffer_ctx *ctx,
2045                         struct lttng_ust_channel_buffer *chan),
2046                 void (*get_value)(void *priv, struct lttng_ust_ctx_value *value),
2047                 void *priv)
2048 {
2049         struct lttng_event_notifier_group *event_notifier_group;
2050
2051         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2052                 int ret;
2053
2054                 ret = lttng_ust_context_set_provider_rcu(
2055                                 &event_notifier_group->ctx,
2056                                 name, get_size, record, get_value, priv);
2057                 if (ret)
2058                         abort();
2059         }
2060 }
2061
2062 int lttng_ust_session_uuid_validate(struct lttng_ust_session *session,
2063                 unsigned char *uuid)
2064 {
2065         if (!session)
2066                 return 0;
2067         /* Compare UUID with session. */
2068         if (session->priv->uuid_set) {
2069                 if (memcmp(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN)) {
2070                         return -1;
2071                 }
2072         } else {
2073                 memcpy(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
2074                 session->priv->uuid_set = true;
2075         }
2076         return 0;
2077
2078 }