src/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 "../libringbuffer/frontend_types.h"
  57 #include "../libringbuffer/frontend.h"
  58 #include "../libcounter/counter.h"
  59 #include "jhash.h"
  60 #include <lttng/ust-abi.h>
  61 #include "context-provider-internal.h"
  62
  63 /*
  64  * All operations within this file are called by the communication
  65  * thread, under ust_lock protection.
  66  */
  67
  68 static CDS_LIST_HEAD(sessions);
  69 static CDS_LIST_HEAD(event_notifier_groups);
  70
  71 struct cds_list_head *lttng_get_sessions(void)
  72 {
  73         return &sessions;
  74 }
  75
  76 static void _lttng_event_destroy(struct lttng_ust_event_common *event);
  77 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  78
  79 static
  80 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session);
  81 static
  82 void lttng_session_sync_event_enablers(struct lttng_ust_session *session);
  83 static
  84 void lttng_event_notifier_group_sync_enablers(
  85                 struct lttng_event_notifier_group *event_notifier_group);
  86 static
  87 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  88
  89 bool lttng_ust_validate_event_name(const struct lttng_ust_event_desc *desc)
  90 {
  91         if (strlen(desc->probe_desc->provider_name) + 1 +
  92                         strlen(desc->event_name) >= LTTNG_UST_ABI_SYM_NAME_LEN)
  93                 return false;
  94         return true;
  95 }
  96
  97 void lttng_ust_format_event_name(const struct lttng_ust_event_desc *desc,
  98                 char *name)
  99 {
 100         strcpy(name, desc->probe_desc->provider_name);
 101         strcat(name, ":");
 102         strcat(name, desc->event_name);
 103 }
 104
 105 /*
 106  * Called with ust lock held.
 107  */
 108 int lttng_session_active(void)
 109 {
 110         struct lttng_ust_session_private *iter;
 111
 112         cds_list_for_each_entry(iter, &sessions, node) {
 113                 if (iter->pub->active)
 114                         return 1;
 115         }
 116         return 0;
 117 }
 118
 119 static
 120 int lttng_loglevel_match(int loglevel,
 121                 unsigned int has_loglevel,
 122                 enum lttng_ust_abi_loglevel_type req_type,
 123                 int req_loglevel)
 124 {
 125         if (!has_loglevel)
 126                 loglevel = TRACE_DEFAULT;
 127         switch (req_type) {
 128         case LTTNG_UST_ABI_LOGLEVEL_RANGE:
 129                 if (loglevel <= req_loglevel
 130                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 131                         return 1;
 132                 else
 133                         return 0;
 134         case LTTNG_UST_ABI_LOGLEVEL_SINGLE:
 135                 if (loglevel == req_loglevel
 136                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 137                         return 1;
 138                 else
 139                         return 0;
 140         case LTTNG_UST_ABI_LOGLEVEL_ALL:
 141         default:
 142                 if (loglevel <= TRACE_DEBUG)
 143                         return 1;
 144                 else
 145                         return 0;
 146         }
 147 }
 148
 149 struct lttng_ust_session *lttng_session_create(void)
 150 {
 151         struct lttng_ust_session *session;
 152         struct lttng_ust_session_private *session_priv;
 153         int i;
 154
 155         session = zmalloc(sizeof(struct lttng_ust_session));
 156         if (!session)
 157                 return NULL;
 158         session->struct_size = sizeof(struct lttng_ust_session);
 159         session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
 160         if (!session_priv) {
 161                 free(session);
 162                 return NULL;
 163         }
 164         session->priv = session_priv;
 165         session_priv->pub = session;
 166         if (lttng_context_init_all(&session->priv->ctx)) {
 167                 free(session_priv);
 168                 free(session);
 169                 return NULL;
 170         }
 171         CDS_INIT_LIST_HEAD(&session->priv->chan_head);
 172         CDS_INIT_LIST_HEAD(&session->priv->events_head);
 173         CDS_INIT_LIST_HEAD(&session->priv->enums_head);
 174         CDS_INIT_LIST_HEAD(&session->priv->enablers_head);
 175         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 176                 CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 177         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 178                 CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
 179         cds_list_add(&session->priv->node, &sessions);
 180         return session;
 181 }
 182
 183 struct lttng_counter *lttng_ust_counter_create(
 184                 const char *counter_transport_name,
 185                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 186 {
 187         struct lttng_counter_transport *counter_transport = NULL;
 188         struct lttng_counter *counter = NULL;
 189
 190         counter_transport = lttng_counter_transport_find(counter_transport_name);
 191         if (!counter_transport)
 192                 goto notransport;
 193         counter = zmalloc(sizeof(struct lttng_counter));
 194         if (!counter)
 195                 goto nomem;
 196
 197         counter->ops = &counter_transport->ops;
 198         counter->transport = counter_transport;
 199
 200         counter->counter = counter->ops->counter_create(
 201                         number_dimensions, dimensions, 0,
 202                         -1, 0, NULL, false);
 203         if (!counter->counter) {
 204                 goto create_error;
 205         }
 206
 207         return counter;
 208
 209 create_error:
 210         free(counter);
 211 nomem:
 212 notransport:
 213         return NULL;
 214 }
 215
 216 static
 217 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 218 {
 219         counter->ops->counter_destroy(counter->counter);
 220         free(counter);
 221 }
 222
 223 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 224 {
 225         struct lttng_event_notifier_group *event_notifier_group;
 226         int i;
 227
 228         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 229         if (!event_notifier_group)
 230                 return NULL;
 231
 232         /* Add all contexts. */
 233         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 234                 free(event_notifier_group);
 235                 return NULL;
 236         }
 237
 238         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 239         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 240         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 241                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 242
 243         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 244
 245         return event_notifier_group;
 246 }
 247
 248 /*
 249  * Only used internally at session destruction.
 250  */
 251 static
 252 void _lttng_channel_unmap(struct lttng_ust_channel_buffer *lttng_chan)
 253 {
 254         struct lttng_ust_lib_ring_buffer_channel *chan;
 255         struct lttng_ust_shm_handle *handle;
 256
 257         cds_list_del(&lttng_chan->priv->node);
 258         lttng_destroy_context(lttng_chan->priv->ctx);
 259         chan = lttng_chan->priv->rb_chan;
 260         handle = chan->handle;
 261         channel_destroy(chan, handle, 0);
 262         free(lttng_chan->parent);
 263         free(lttng_chan->priv);
 264         free(lttng_chan);
 265 }
 266
 267 static
 268 void register_event(struct lttng_ust_event_common *event)
 269 {
 270         int ret;
 271         const struct lttng_ust_event_desc *desc;
 272         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 273
 274         assert(event->priv->registered == 0);
 275         desc = event->priv->desc;
 276         lttng_ust_format_event_name(desc, name);
 277         ret = lttng_ust_tp_probe_register_queue_release(name,
 278                         desc->probe_callback,
 279                         event, desc->signature);
 280         WARN_ON_ONCE(ret);
 281         if (!ret)
 282                 event->priv->registered = 1;
 283 }
 284
 285 static
 286 void unregister_event(struct lttng_ust_event_common *event)
 287 {
 288         int ret;
 289         const struct lttng_ust_event_desc *desc;
 290         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 291
 292         assert(event->priv->registered == 1);
 293         desc = event->priv->desc;
 294         lttng_ust_format_event_name(desc, name);
 295         ret = lttng_ust_tp_probe_unregister_queue_release(name,
 296                         desc->probe_callback,
 297                         event);
 298         WARN_ON_ONCE(ret);
 299         if (!ret)
 300                 event->priv->registered = 0;
 301 }
 302
 303 static
 304 void _lttng_event_unregister(struct lttng_ust_event_common *event)
 305 {
 306         if (event->priv->registered)
 307                 unregister_event(event);
 308 }
 309
 310 void lttng_session_destroy(struct lttng_ust_session *session)
 311 {
 312         struct lttng_ust_channel_buffer_private *chan, *tmpchan;
 313         struct lttng_ust_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
 314         struct lttng_enum *_enum, *tmp_enum;
 315         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 316
 317         CMM_ACCESS_ONCE(session->active) = 0;
 318         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
 319                 _lttng_event_unregister(event_recorder_priv->parent.pub);
 320         }
 321         lttng_ust_urcu_synchronize_rcu();       /* Wait for in-flight events to complete */
 322         lttng_ust_tp_probe_prune_release_queue();
 323         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 324                         &session->priv->enablers_head, node)
 325                 lttng_event_enabler_destroy(event_enabler);
 326         cds_list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv,
 327                         &session->priv->events_head, node)
 328                 _lttng_event_destroy(event_recorder_priv->parent.pub);
 329         cds_list_for_each_entry_safe(_enum, tmp_enum,
 330                         &session->priv->enums_head, node)
 331                 _lttng_enum_destroy(_enum);
 332         cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 333                 _lttng_channel_unmap(chan->pub);
 334         cds_list_del(&session->priv->node);
 335         lttng_destroy_context(session->priv->ctx);
 336         free(session->priv);
 337         free(session);
 338 }
 339
 340 void lttng_event_notifier_group_destroy(
 341                 struct lttng_event_notifier_group *event_notifier_group)
 342 {
 343         int close_ret;
 344         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 345         struct lttng_ust_event_notifier_private *event_notifier_priv, *tmpevent_notifier_priv;
 346
 347         if (!event_notifier_group) {
 348                 return;
 349         }
 350
 351         cds_list_for_each_entry(event_notifier_priv,
 352                         &event_notifier_group->event_notifiers_head, node)
 353                 _lttng_event_unregister(event_notifier_priv->parent.pub);
 354
 355         lttng_ust_urcu_synchronize_rcu();
 356
 357         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 358                         &event_notifier_group->enablers_head, node)
 359                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 360
 361         cds_list_for_each_entry_safe(event_notifier_priv, tmpevent_notifier_priv,
 362                         &event_notifier_group->event_notifiers_head, node)
 363                 _lttng_event_destroy(event_notifier_priv->parent.pub);
 364
 365         if (event_notifier_group->error_counter)
 366                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 367
 368         /* Close the notification fd to the listener of event_notifiers. */
 369
 370         lttng_ust_lock_fd_tracker();
 371         close_ret = close(event_notifier_group->notification_fd);
 372         if (!close_ret) {
 373                 lttng_ust_delete_fd_from_tracker(
 374                                 event_notifier_group->notification_fd);
 375         } else {
 376                 PERROR("close");
 377                 abort();
 378         }
 379         lttng_ust_unlock_fd_tracker();
 380
 381         cds_list_del(&event_notifier_group->node);
 382
 383         free(event_notifier_group);
 384 }
 385
 386 static
 387 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 388 {
 389         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 390         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 391
 392         if (!enabler) {
 393                 return;
 394         }
 395
 396         /* Destroy filter bytecode */
 397         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 398                         &enabler->filter_bytecode_head, node) {
 399                 free(filter_node);
 400         }
 401
 402         /* Destroy excluders */
 403         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 404                         &enabler->excluder_head, node) {
 405                 free(excluder_node);
 406         }
 407 }
 408
 409  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 410 {
 411         if (!event_notifier_enabler) {
 412                 return;
 413         }
 414
 415         cds_list_del(&event_notifier_enabler->node);
 416
 417         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 418
 419         free(event_notifier_enabler);
 420 }
 421
 422 static
 423 int lttng_enum_create(const struct lttng_ust_enum_desc *desc,
 424                 struct lttng_ust_session *session)
 425 {
 426         const char *enum_name = desc->name;
 427         struct lttng_enum *_enum;
 428         struct cds_hlist_head *head;
 429         int ret = 0;
 430         size_t name_len = strlen(enum_name);
 431         uint32_t hash;
 432         int notify_socket;
 433
 434         /* Check if this enum is already registered for this session. */
 435         hash = jhash(enum_name, name_len, 0);
 436         head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 437
 438         _enum = lttng_ust_enum_get_from_desc(session, desc);
 439         if (_enum) {
 440                 ret = -EEXIST;
 441                 goto exist;
 442         }
 443
 444         notify_socket = lttng_get_notify_socket(session->priv->owner);
 445         if (notify_socket < 0) {
 446                 ret = notify_socket;
 447                 goto socket_error;
 448         }
 449
 450         _enum = zmalloc(sizeof(*_enum));
 451         if (!_enum) {
 452                 ret = -ENOMEM;
 453                 goto cache_error;
 454         }
 455         _enum->session = session;
 456         _enum->desc = desc;
 457
 458         ret = ustcomm_register_enum(notify_socket,
 459                 session->priv->objd,
 460                 enum_name,
 461                 desc->nr_entries,
 462                 desc->entries,
 463                 &_enum->id);
 464         if (ret < 0) {
 465                 DBG("Error (%d) registering enumeration to sessiond", ret);
 466                 goto sessiond_register_error;
 467         }
 468         cds_list_add(&_enum->node, &session->priv->enums_head);
 469         cds_hlist_add_head(&_enum->hlist, head);
 470         return 0;
 471
 472 sessiond_register_error:
 473         free(_enum);
 474 cache_error:
 475 socket_error:
 476 exist:
 477         return ret;
 478 }
 479
 480 static
 481 int lttng_create_enum_check(const struct lttng_ust_type_common *type,
 482                 struct lttng_ust_session *session)
 483 {
 484         switch (type->type) {
 485         case lttng_ust_type_enum:
 486         {
 487                 const struct lttng_ust_enum_desc *enum_desc;
 488                 int ret;
 489
 490                 enum_desc = lttng_ust_get_type_enum(type)->desc;
 491                 ret = lttng_enum_create(enum_desc, session);
 492                 if (ret && ret != -EEXIST) {
 493                         DBG("Unable to create enum error: (%d)", ret);
 494                         return ret;
 495                 }
 496                 break;
 497         }
 498         case lttng_ust_type_dynamic:
 499         {
 500                 const struct lttng_ust_event_field *tag_field_generic;
 501                 const struct lttng_ust_enum_desc *enum_desc;
 502                 int ret;
 503
 504                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 505                 enum_desc = lttng_ust_get_type_enum(tag_field_generic->type)->desc;
 506                 ret = lttng_enum_create(enum_desc, session);
 507                 if (ret && ret != -EEXIST) {
 508                         DBG("Unable to create enum error: (%d)", ret);
 509                         return ret;
 510                 }
 511                 break;
 512         }
 513         default:
 514                 /* TODO: nested types when they become supported. */
 515                 break;
 516         }
 517         return 0;
 518 }
 519
 520 static
 521 int lttng_create_all_event_enums(size_t nr_fields,
 522                 const struct lttng_ust_event_field **event_fields,
 523                 struct lttng_ust_session *session)
 524 {
 525         size_t i;
 526         int ret;
 527
 528         /* For each field, ensure enum is part of the session. */
 529         for (i = 0; i < nr_fields; i++) {
 530                 const struct lttng_ust_type_common *type = event_fields[i]->type;
 531
 532                 ret = lttng_create_enum_check(type, session);
 533                 if (ret)
 534                         return ret;
 535         }
 536         return 0;
 537 }
 538
 539 static
 540 int lttng_create_all_ctx_enums(size_t nr_fields,
 541                 struct lttng_ust_ctx_field *ctx_fields,
 542                 struct lttng_ust_session *session)
 543 {
 544         size_t i;
 545         int ret;
 546
 547         /* For each field, ensure enum is part of the session. */
 548         for (i = 0; i < nr_fields; i++) {
 549                 const struct lttng_ust_type_common *type = ctx_fields[i].event_field->type;
 550
 551                 ret = lttng_create_enum_check(type, session);
 552                 if (ret)
 553                         return ret;
 554         }
 555         return 0;
 556 }
 557
 558 /*
 559  * Ensure that a state-dump will be performed for this session at the end
 560  * of the current handle_message().
 561  */
 562 int lttng_session_statedump(struct lttng_ust_session *session)
 563 {
 564         session->priv->statedump_pending = 1;
 565         lttng_ust_sockinfo_session_enabled(session->priv->owner);
 566         return 0;
 567 }
 568
 569 int lttng_session_enable(struct lttng_ust_session *session)
 570 {
 571         int ret = 0;
 572         struct lttng_ust_channel_buffer_private *chan;
 573         int notify_socket;
 574
 575         if (session->active) {
 576                 ret = -EBUSY;
 577                 goto end;
 578         }
 579
 580         notify_socket = lttng_get_notify_socket(session->priv->owner);
 581         if (notify_socket < 0)
 582                 return notify_socket;
 583
 584         /* Set transient enabler state to "enabled" */
 585         session->priv->tstate = 1;
 586
 587         /* We need to sync enablers with session before activation. */
 588         lttng_session_sync_event_enablers(session);
 589
 590         /*
 591          * Snapshot the number of events per channel to know the type of header
 592          * we need to use.
 593          */
 594         cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 595                 struct lttng_ust_ctx *ctx;
 596                 struct lttng_ust_ctx_field *fields = NULL;
 597                 size_t nr_fields = 0;
 598                 uint32_t chan_id;
 599
 600                 /* don't change it if session stop/restart */
 601                 if (chan->header_type)
 602                         continue;
 603                 ctx = chan->ctx;
 604                 if (ctx) {
 605                         nr_fields = ctx->nr_fields;
 606                         fields = ctx->fields;
 607                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 608                                 session);
 609                         if (ret < 0) {
 610                                 DBG("Error (%d) adding enum to session", ret);
 611                                 return ret;
 612                         }
 613                 }
 614                 ret = ustcomm_register_channel(notify_socket,
 615                         session,
 616                         session->priv->objd,
 617                         chan->parent.objd,
 618                         nr_fields,
 619                         fields,
 620                         &chan_id,
 621                         &chan->header_type);
 622                 if (ret) {
 623                         DBG("Error (%d) registering channel to sessiond", ret);
 624                         return ret;
 625                 }
 626                 if (chan_id != chan->id) {
 627                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 628                                 chan_id, chan->id);
 629                         return -EINVAL;
 630                 }
 631         }
 632
 633         /* Set atomically the state to "active" */
 634         CMM_ACCESS_ONCE(session->active) = 1;
 635         CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 636
 637         ret = lttng_session_statedump(session);
 638         if (ret)
 639                 return ret;
 640 end:
 641         return ret;
 642 }
 643
 644 int lttng_session_disable(struct lttng_ust_session *session)
 645 {
 646         int ret = 0;
 647
 648         if (!session->active) {
 649                 ret = -EBUSY;
 650                 goto end;
 651         }
 652         /* Set atomically the state to "inactive" */
 653         CMM_ACCESS_ONCE(session->active) = 0;
 654
 655         /* Set transient enabler state to "disabled" */
 656         session->priv->tstate = 0;
 657         lttng_session_sync_event_enablers(session);
 658 end:
 659         return ret;
 660 }
 661
 662 int lttng_channel_enable(struct lttng_ust_channel_common *lttng_channel)
 663 {
 664         int ret = 0;
 665
 666         if (lttng_channel->enabled) {
 667                 ret = -EBUSY;
 668                 goto end;
 669         }
 670         /* Set transient enabler state to "enabled" */
 671         lttng_channel->priv->tstate = 1;
 672         lttng_session_sync_event_enablers(lttng_channel->session);
 673         /* Set atomically the state to "enabled" */
 674         CMM_ACCESS_ONCE(lttng_channel->enabled) = 1;
 675 end:
 676         return ret;
 677 }
 678
 679 int lttng_channel_disable(struct lttng_ust_channel_common *lttng_channel)
 680 {
 681         int ret = 0;
 682
 683         if (!lttng_channel->enabled) {
 684                 ret = -EBUSY;
 685                 goto end;
 686         }
 687         /* Set atomically the state to "disabled" */
 688         CMM_ACCESS_ONCE(lttng_channel->enabled) = 0;
 689         /* Set transient enabler state to "enabled" */
 690         lttng_channel->priv->tstate = 0;
 691         lttng_session_sync_event_enablers(lttng_channel->session);
 692 end:
 693         return ret;
 694 }
 695
 696 static inline
 697 struct cds_hlist_head *borrow_hash_table_bucket(
 698                 struct cds_hlist_head *hash_table,
 699                 unsigned int hash_table_size,
 700                 const struct lttng_ust_event_desc *desc)
 701 {
 702         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 703         size_t name_len;
 704         uint32_t hash;
 705
 706         lttng_ust_format_event_name(desc, name);
 707         name_len = strlen(name);
 708
 709         hash = jhash(name, name_len, 0);
 710         return &hash_table[hash & (hash_table_size - 1)];
 711 }
 712
 713 /*
 714  * Supports event creation while tracing session is active.
 715  */
 716 static
 717 int lttng_event_recorder_create(const struct lttng_ust_event_desc *desc,
 718                 struct lttng_ust_channel_buffer *chan)
 719 {
 720         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 721         struct lttng_ust_event_recorder *event_recorder;
 722         struct lttng_ust_event_recorder_private *event_recorder_priv;
 723         struct lttng_ust_session *session = chan->parent->session;
 724         struct cds_hlist_head *head;
 725         int ret = 0;
 726         int notify_socket, loglevel;
 727         const char *uri;
 728
 729         head = borrow_hash_table_bucket(chan->parent->session->priv->events_ht.table,
 730                 LTTNG_UST_EVENT_HT_SIZE, desc);
 731
 732         notify_socket = lttng_get_notify_socket(session->priv->owner);
 733         if (notify_socket < 0) {
 734                 ret = notify_socket;
 735                 goto socket_error;
 736         }
 737
 738         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 739                         session);
 740         if (ret < 0) {
 741                 DBG("Error (%d) adding enum to session", ret);
 742                 goto create_enum_error;
 743         }
 744
 745         /*
 746          * Check if loglevel match. Refuse to connect event if not.
 747          */
 748         event_recorder = zmalloc(sizeof(struct lttng_ust_event_recorder));
 749         if (!event_recorder) {
 750                 ret = -ENOMEM;
 751                 goto cache_error;
 752         }
 753         event_recorder->struct_size = sizeof(struct lttng_ust_event_recorder);
 754
 755         event_recorder->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 756         if (!event_recorder->parent) {
 757                 ret = -ENOMEM;
 758                 goto parent_error;
 759         }
 760         event_recorder->parent->struct_size = sizeof(struct lttng_ust_event_common);
 761         event_recorder->parent->type = LTTNG_UST_EVENT_TYPE_RECORDER;
 762         event_recorder->parent->child = event_recorder;
 763
 764         event_recorder_priv = zmalloc(sizeof(struct lttng_ust_event_recorder_private));
 765         if (!event_recorder_priv) {
 766                 ret = -ENOMEM;
 767                 goto priv_error;
 768         }
 769         event_recorder->priv = event_recorder_priv;
 770         event_recorder_priv->pub = event_recorder;
 771         event_recorder->parent->priv = &event_recorder_priv->parent;
 772         event_recorder_priv->parent.pub = event_recorder->parent;
 773
 774         event_recorder->chan = chan;
 775
 776         /* Event will be enabled by enabler sync. */
 777         event_recorder->parent->run_filter = lttng_ust_interpret_event_filter;
 778         event_recorder->parent->enabled = 0;
 779         event_recorder->parent->priv->registered = 0;
 780         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->filter_bytecode_runtime_head);
 781         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 782         event_recorder->parent->priv->desc = desc;
 783
 784         if (desc->loglevel)
 785                 loglevel = *(*event_recorder->parent->priv->desc->loglevel);
 786         else
 787                 loglevel = TRACE_DEFAULT;
 788         if (desc->model_emf_uri)
 789                 uri = *(desc->model_emf_uri);
 790         else
 791                 uri = NULL;
 792
 793         lttng_ust_format_event_name(desc, name);
 794
 795         /* Fetch event ID from sessiond */
 796         ret = ustcomm_register_event(notify_socket,
 797                 session,
 798                 session->priv->objd,
 799                 chan->priv->parent.objd,
 800                 name,
 801                 loglevel,
 802                 desc->signature,
 803                 desc->nr_fields,
 804                 desc->fields,
 805                 uri,
 806                 &event_recorder->priv->id);
 807         if (ret < 0) {
 808                 DBG("Error (%d) registering event to sessiond", ret);
 809                 goto sessiond_register_error;
 810         }
 811
 812         cds_list_add(&event_recorder_priv->node, &chan->parent->session->priv->events_head);
 813         cds_hlist_add_head(&event_recorder_priv->hlist, head);
 814         return 0;
 815
 816 sessiond_register_error:
 817         free(event_recorder_priv);
 818 priv_error:
 819         free(event_recorder->parent);
 820 parent_error:
 821         free(event_recorder);
 822 cache_error:
 823 create_enum_error:
 824 socket_error:
 825         return ret;
 826 }
 827
 828 static
 829 int lttng_event_notifier_create(const struct lttng_ust_event_desc *desc,
 830                 uint64_t token, uint64_t error_counter_index,
 831                 struct lttng_event_notifier_group *event_notifier_group)
 832 {
 833         struct lttng_ust_event_notifier *event_notifier;
 834         struct lttng_ust_event_notifier_private *event_notifier_priv;
 835         struct cds_hlist_head *head;
 836         int ret = 0;
 837
 838         /*
 839          * Get the hashtable bucket the created lttng_event_notifier object
 840          * should be inserted.
 841          */
 842         head = borrow_hash_table_bucket(
 843                 event_notifier_group->event_notifiers_ht.table,
 844                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 845
 846         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 847         if (!event_notifier) {
 848                 ret = -ENOMEM;
 849                 goto error;
 850         }
 851         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 852
 853         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 854         if (!event_notifier->parent) {
 855                 ret = -ENOMEM;
 856                 goto parent_error;
 857         }
 858         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 859         event_notifier->parent->type = LTTNG_UST_EVENT_TYPE_NOTIFIER;
 860         event_notifier->parent->child = event_notifier;
 861
 862         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 863         if (!event_notifier_priv) {
 864                 ret = -ENOMEM;
 865                 goto priv_error;
 866         }
 867         event_notifier->priv = event_notifier_priv;
 868         event_notifier_priv->pub = event_notifier;
 869         event_notifier->parent->priv = &event_notifier_priv->parent;
 870         event_notifier_priv->parent.pub = event_notifier->parent;
 871
 872         event_notifier_priv->group = event_notifier_group;
 873         event_notifier_priv->parent.user_token = token;
 874         event_notifier_priv->error_counter_index = error_counter_index;
 875
 876         /* Event notifier will be enabled by enabler sync. */
 877         event_notifier->parent->run_filter = lttng_ust_interpret_event_filter;
 878         event_notifier->parent->enabled = 0;
 879         event_notifier_priv->parent.registered = 0;
 880
 881         CDS_INIT_LIST_HEAD(&event_notifier->parent->priv->filter_bytecode_runtime_head);
 882         CDS_INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
 883         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 884         event_notifier_priv->parent.desc = desc;
 885         event_notifier->notification_send = lttng_event_notifier_notification_send;
 886
 887         cds_list_add(&event_notifier_priv->node,
 888                         &event_notifier_group->event_notifiers_head);
 889         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 890
 891         return 0;
 892
 893 priv_error:
 894         free(event_notifier->parent);
 895 parent_error:
 896         free(event_notifier);
 897 error:
 898         return ret;
 899 }
 900
 901 static
 902 int lttng_desc_match_star_glob_enabler(const struct lttng_ust_event_desc *desc,
 903                 struct lttng_enabler *enabler)
 904 {
 905         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 906         int loglevel = 0;
 907         unsigned int has_loglevel = 0;
 908
 909         lttng_ust_format_event_name(desc, name);
 910         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 911         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 912                         name, SIZE_MAX))
 913                 return 0;
 914         if (desc->loglevel) {
 915                 loglevel = *(*desc->loglevel);
 916                 has_loglevel = 1;
 917         }
 918         if (!lttng_loglevel_match(loglevel,
 919                         has_loglevel,
 920                         enabler->event_param.loglevel_type,
 921                         enabler->event_param.loglevel))
 922                 return 0;
 923         return 1;
 924 }
 925
 926 static
 927 int lttng_desc_match_event_enabler(const struct lttng_ust_event_desc *desc,
 928                 struct lttng_enabler *enabler)
 929 {
 930         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 931         int loglevel = 0;
 932         unsigned int has_loglevel = 0;
 933
 934         lttng_ust_format_event_name(desc, name);
 935         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 936         if (strcmp(name, enabler->event_param.name))
 937                 return 0;
 938         if (desc->loglevel) {
 939                 loglevel = *(*desc->loglevel);
 940                 has_loglevel = 1;
 941         }
 942         if (!lttng_loglevel_match(loglevel,
 943                         has_loglevel,
 944                         enabler->event_param.loglevel_type,
 945                         enabler->event_param.loglevel))
 946                 return 0;
 947         return 1;
 948 }
 949
 950 static
 951 int lttng_desc_match_enabler(const struct lttng_ust_event_desc *desc,
 952                 struct lttng_enabler *enabler)
 953 {
 954         switch (enabler->format_type) {
 955         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 956         {
 957                 struct lttng_ust_excluder_node *excluder;
 958
 959                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 960                         return 0;
 961                 }
 962
 963                 /*
 964                  * If the matching event matches with an excluder,
 965                  * return 'does not match'
 966                  */
 967                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 968                         int count;
 969
 970                         for (count = 0; count < excluder->excluder.count; count++) {
 971                                 int len;
 972                                 char *excluder_name;
 973
 974                                 excluder_name = (char *) (excluder->excluder.names)
 975                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
 976                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 977                                 if (len > 0) {
 978                                         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 979
 980                                         lttng_ust_format_event_name(desc, name);
 981                                         if (strutils_star_glob_match(excluder_name, len, name, SIZE_MAX)) {
 982                                                 return 0;
 983                                         }
 984                                 }
 985                         }
 986                 }
 987                 return 1;
 988         }
 989         case LTTNG_ENABLER_FORMAT_EVENT:
 990                 return lttng_desc_match_event_enabler(desc, enabler);
 991         default:
 992                 return -EINVAL;
 993         }
 994 }
 995
 996 static
 997 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 998                 struct lttng_ust_event_recorder *event_recorder)
 999 {
1000         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
1001                         lttng_event_enabler_as_enabler(event_enabler))
1002                         && event_recorder->chan == event_enabler->chan)
1003                 return 1;
1004         else
1005                 return 0;
1006 }
1007
1008 static
1009 int lttng_event_notifier_enabler_match_event_notifier(
1010                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1011                 struct lttng_ust_event_notifier *event_notifier)
1012 {
1013         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
1014                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1015
1016         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
1017                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
1018                 return 1;
1019         else
1020                 return 0;
1021 }
1022
1023 static
1024 struct lttng_enabler_ref *lttng_enabler_ref(
1025                 struct cds_list_head *enabler_ref_list,
1026                 struct lttng_enabler *enabler)
1027 {
1028         struct lttng_enabler_ref *enabler_ref;
1029
1030         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1031                 if (enabler_ref->ref == enabler)
1032                         return enabler_ref;
1033         }
1034         return NULL;
1035 }
1036
1037 /*
1038  * Create struct lttng_event if it is missing and present in the list of
1039  * tracepoint probes.
1040  */
1041 static
1042 void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_enabler)
1043 {
1044         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1045         struct lttng_ust_registered_probe *reg_probe;
1046         const struct lttng_ust_event_desc *desc;
1047         struct lttng_ust_event_recorder_private *event_recorder_priv;
1048         int i;
1049         struct cds_list_head *probe_list;
1050
1051         probe_list = lttng_get_probe_list_head();
1052         /*
1053          * For each probe event, if we find that a probe event matches
1054          * our enabler, create an associated lttng_event if not
1055          * already present.
1056          */
1057         cds_list_for_each_entry(reg_probe, probe_list, head) {
1058                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1059
1060                 for (i = 0; i < probe_desc->nr_events; i++) {
1061                         int ret;
1062                         bool found = false;
1063                         struct cds_hlist_head *head;
1064                         struct cds_hlist_node *node;
1065
1066                         desc = probe_desc->event_desc[i];
1067                         if (!lttng_desc_match_enabler(desc,
1068                                         lttng_event_enabler_as_enabler(event_enabler)))
1069                                 continue;
1070
1071                         head = borrow_hash_table_bucket(
1072                                 session->priv->events_ht.table,
1073                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1074
1075                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1076                                 if (event_recorder_priv->parent.desc == desc
1077                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1078                                         found = true;
1079                                         break;
1080                                 }
1081                         }
1082                         if (found)
1083                                 continue;
1084
1085                         /*
1086                          * We need to create an event for this
1087                          * event probe.
1088                          */
1089                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1090                                         event_enabler->chan);
1091                         if (ret) {
1092                                 DBG("Unable to create event \"%s:%s\", error %d\n",
1093                                         probe_desc->provider_name,
1094                                         probe_desc->event_desc[i]->event_name, ret);
1095                         }
1096                 }
1097         }
1098 }
1099
1100 static
1101 void probe_provider_event_for_each(const struct lttng_ust_probe_desc *provider_desc,
1102                 void (*event_func)(struct lttng_ust_event_common *event))
1103 {
1104         struct cds_hlist_node *node, *tmp_node;
1105         struct cds_list_head *sessionsp;
1106         unsigned int i;
1107
1108         /* Get handle on list of sessions. */
1109         sessionsp = lttng_get_sessions();
1110
1111         /*
1112          * Iterate over all events in the probe provider descriptions and
1113          * sessions to queue the unregistration of the events.
1114          */
1115         for (i = 0; i < provider_desc->nr_events; i++) {
1116                 const struct lttng_ust_event_desc *event_desc;
1117                 struct lttng_event_notifier_group *event_notifier_group;
1118                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1119                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1120                 struct lttng_ust_session_private *session_priv;
1121                 struct cds_hlist_head *head;
1122
1123                 event_desc = provider_desc->event_desc[i];
1124
1125                 /*
1126                  * Iterate over all session to find the current event
1127                  * description.
1128                  */
1129                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1130                         /*
1131                          * Get the list of events in the hashtable bucket and
1132                          * iterate to find the event matching this descriptor.
1133                          */
1134                         head = borrow_hash_table_bucket(
1135                                 session_priv->events_ht.table,
1136                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1137
1138                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1139                                 if (event_desc == event_recorder_priv->parent.desc) {
1140                                         event_func(event_recorder_priv->parent.pub);
1141                                         break;
1142                                 }
1143                         }
1144                 }
1145
1146                 /*
1147                  * Iterate over all event_notifier groups to find the current event
1148                  * description.
1149                  */
1150                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1151                         /*
1152                          * Get the list of event_notifiers in the hashtable bucket and
1153                          * iterate to find the event_notifier matching this
1154                          * descriptor.
1155                          */
1156                         head = borrow_hash_table_bucket(
1157                                 event_notifier_group->event_notifiers_ht.table,
1158                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1159
1160                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1161                                 if (event_desc == event_notifier_priv->parent.desc) {
1162                                         event_func(event_notifier_priv->parent.pub);
1163                                         break;
1164                                 }
1165                         }
1166                 }
1167         }
1168 }
1169
1170 static
1171 void _event_enum_destroy(struct lttng_ust_event_common *event)
1172 {
1173
1174         switch (event->type) {
1175         case LTTNG_UST_EVENT_TYPE_RECORDER:
1176         {
1177                 struct lttng_ust_event_recorder *event_recorder = event->child;
1178                 struct lttng_ust_session *session = event_recorder->chan->parent->session;
1179                 unsigned int i;
1180
1181                 /* Destroy enums of the current event. */
1182                 for (i = 0; i < event_recorder->parent->priv->desc->nr_fields; i++) {
1183                         const struct lttng_ust_enum_desc *enum_desc;
1184                         const struct lttng_ust_event_field *field;
1185                         struct lttng_enum *curr_enum;
1186
1187                         field = event_recorder->parent->priv->desc->fields[i];
1188                         switch (field->type->type) {
1189                         case lttng_ust_type_enum:
1190                                 enum_desc = lttng_ust_get_type_enum(field->type)->desc;
1191                                 break;
1192                         default:
1193                                 continue;
1194                         }
1195
1196                         curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1197                         if (curr_enum) {
1198                                 _lttng_enum_destroy(curr_enum);
1199                         }
1200                 }
1201                 break;
1202         }
1203         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1204                 break;
1205         default:
1206                 abort();
1207         }
1208         /* Destroy event. */
1209         _lttng_event_destroy(event);
1210 }
1211
1212 /*
1213  * Iterate over all the UST sessions to unregister and destroy all probes from
1214  * the probe provider descriptor received as argument. Must me called with the
1215  * ust_lock held.
1216  */
1217 void lttng_probe_provider_unregister_events(
1218                 const struct lttng_ust_probe_desc *provider_desc)
1219 {
1220         /*
1221          * Iterate over all events in the probe provider descriptions and sessions
1222          * to queue the unregistration of the events.
1223          */
1224         probe_provider_event_for_each(provider_desc, _lttng_event_unregister);
1225
1226         /* Wait for grace period. */
1227         lttng_ust_urcu_synchronize_rcu();
1228         /* Prune the unregistration queue. */
1229         lttng_ust_tp_probe_prune_release_queue();
1230
1231         /*
1232          * It is now safe to destroy the events and remove them from the event list
1233          * and hashtables.
1234          */
1235         probe_provider_event_for_each(provider_desc, _event_enum_destroy);
1236 }
1237
1238 /*
1239  * Create events associated with an event enabler (if not already present),
1240  * and add backward reference from the event to the enabler.
1241  */
1242 static
1243 int lttng_event_enabler_ref_event_recorders(struct lttng_event_enabler *event_enabler)
1244 {
1245         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1246         struct lttng_ust_event_recorder_private *event_recorder_priv;
1247
1248         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1249                 goto end;
1250
1251         /* First ensure that probe events are created for this enabler. */
1252         lttng_create_event_recorder_if_missing(event_enabler);
1253
1254         /* For each event matching enabler in session event list. */
1255         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1256                 struct lttng_enabler_ref *enabler_ref;
1257
1258                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1259                         continue;
1260
1261                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1262                         lttng_event_enabler_as_enabler(event_enabler));
1263                 if (!enabler_ref) {
1264                         /*
1265                          * If no backward ref, create it.
1266                          * Add backward ref from event to enabler.
1267                          */
1268                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1269                         if (!enabler_ref)
1270                                 return -ENOMEM;
1271                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1272                                 event_enabler);
1273                         cds_list_add(&enabler_ref->node,
1274                                 &event_recorder_priv->parent.enablers_ref_head);
1275                 }
1276
1277                 /*
1278                  * Link filter bytecodes if not linked yet.
1279                  */
1280                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1281                         &session->priv->ctx,
1282                         &event_recorder_priv->parent.filter_bytecode_runtime_head,
1283                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1284
1285                 /* TODO: merge event context. */
1286         }
1287 end:
1288         return 0;
1289 }
1290
1291 /*
1292  * Called at library load: connect the probe on all enablers matching
1293  * this event.
1294  * Called with session mutex held.
1295  */
1296 int lttng_fix_pending_events(void)
1297 {
1298         struct lttng_ust_session_private *session_priv;
1299
1300         cds_list_for_each_entry(session_priv, &sessions, node) {
1301                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1302         }
1303         return 0;
1304 }
1305
1306 int lttng_fix_pending_event_notifiers(void)
1307 {
1308         struct lttng_event_notifier_group *event_notifier_group;
1309
1310         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1311                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1312         }
1313         return 0;
1314 }
1315
1316 /*
1317  * For each session of the owner thread, execute pending statedump.
1318  * Only dump state for the sessions owned by the caller thread, because
1319  * we don't keep ust_lock across the entire iteration.
1320  */
1321 void lttng_handle_pending_statedump(void *owner)
1322 {
1323         struct lttng_ust_session_private *session_priv;
1324
1325         /* Execute state dump */
1326         do_lttng_ust_statedump(owner);
1327
1328         /* Clear pending state dump */
1329         if (ust_lock()) {
1330                 goto end;
1331         }
1332         cds_list_for_each_entry(session_priv, &sessions, node) {
1333                 if (session_priv->owner != owner)
1334                         continue;
1335                 if (!session_priv->statedump_pending)
1336                         continue;
1337                 session_priv->statedump_pending = 0;
1338         }
1339 end:
1340         ust_unlock();
1341         return;
1342 }
1343
1344 static
1345 void _lttng_event_destroy(struct lttng_ust_event_common *event)
1346 {
1347         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1348
1349         lttng_free_event_filter_runtime(event);
1350         /* Free event enabler refs */
1351         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1352                         &event->priv->enablers_ref_head, node)
1353                 free(enabler_ref);
1354
1355         switch (event->type) {
1356         case LTTNG_UST_EVENT_TYPE_RECORDER:
1357         {
1358                 struct lttng_ust_event_recorder *event_recorder = event->child;
1359
1360                 /* Remove from event list. */
1361                 cds_list_del(&event_recorder->priv->node);
1362                 /* Remove from event hash table. */
1363                 cds_hlist_del(&event_recorder->priv->hlist);
1364
1365                 lttng_destroy_context(event_recorder->priv->ctx);
1366                 free(event_recorder->parent);
1367                 free(event_recorder->priv);
1368                 free(event_recorder);
1369                 break;
1370         }
1371         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1372         {
1373                 struct lttng_ust_event_notifier *event_notifier = event->child;
1374
1375                 /* Remove from event list. */
1376                 cds_list_del(&event_notifier->priv->node);
1377                 /* Remove from event hash table. */
1378                 cds_hlist_del(&event_notifier->priv->hlist);
1379
1380                 free(event_notifier->priv);
1381                 free(event_notifier->parent);
1382                 free(event_notifier);
1383                 break;
1384         }
1385         default:
1386                 abort();
1387         }
1388 }
1389
1390 static
1391 void _lttng_enum_destroy(struct lttng_enum *_enum)
1392 {
1393         cds_list_del(&_enum->node);
1394         cds_hlist_del(&_enum->hlist);
1395         free(_enum);
1396 }
1397
1398 void lttng_ust_abi_events_exit(void)
1399 {
1400         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1401
1402         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1403                 lttng_session_destroy(session_priv->pub);
1404 }
1405
1406 /*
1407  * Enabler management.
1408  */
1409 struct lttng_event_enabler *lttng_event_enabler_create(
1410                 enum lttng_enabler_format_type format_type,
1411                 struct lttng_ust_abi_event *event_param,
1412                 struct lttng_ust_channel_buffer *chan)
1413 {
1414         struct lttng_event_enabler *event_enabler;
1415
1416         event_enabler = zmalloc(sizeof(*event_enabler));
1417         if (!event_enabler)
1418                 return NULL;
1419         event_enabler->base.format_type = format_type;
1420         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1421         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1422         memcpy(&event_enabler->base.event_param, event_param,
1423                 sizeof(event_enabler->base.event_param));
1424         event_enabler->chan = chan;
1425         /* ctx left NULL */
1426         event_enabler->base.enabled = 0;
1427         cds_list_add(&event_enabler->node, &event_enabler->chan->parent->session->priv->enablers_head);
1428         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1429
1430         return event_enabler;
1431 }
1432
1433 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1434                 struct lttng_event_notifier_group *event_notifier_group,
1435                 enum lttng_enabler_format_type format_type,
1436                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1437 {
1438         struct lttng_event_notifier_enabler *event_notifier_enabler;
1439
1440         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1441         if (!event_notifier_enabler)
1442                 return NULL;
1443         event_notifier_enabler->base.format_type = format_type;
1444         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1445         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1446         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1447
1448         event_notifier_enabler->user_token = event_notifier_param->event.token;
1449         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1450         event_notifier_enabler->num_captures = 0;
1451
1452         memcpy(&event_notifier_enabler->base.event_param.name,
1453                 event_notifier_param->event.name,
1454                 sizeof(event_notifier_enabler->base.event_param.name));
1455         event_notifier_enabler->base.event_param.instrumentation =
1456                 event_notifier_param->event.instrumentation;
1457         event_notifier_enabler->base.event_param.loglevel =
1458                 event_notifier_param->event.loglevel;
1459         event_notifier_enabler->base.event_param.loglevel_type =
1460                 event_notifier_param->event.loglevel_type;
1461
1462         event_notifier_enabler->base.enabled = 0;
1463         event_notifier_enabler->group = event_notifier_group;
1464
1465         cds_list_add(&event_notifier_enabler->node,
1466                         &event_notifier_group->enablers_head);
1467
1468         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1469
1470         return event_notifier_enabler;
1471 }
1472
1473 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1474 {
1475         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1476         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1477
1478         return 0;
1479 }
1480
1481 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1482 {
1483         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1484         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1485
1486         return 0;
1487 }
1488
1489 static
1490 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1491                 struct lttng_ust_bytecode_node **bytecode)
1492 {
1493         (*bytecode)->enabler = enabler;
1494         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1495         /* Take ownership of bytecode */
1496         *bytecode = NULL;
1497 }
1498
1499 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1500                 struct lttng_ust_bytecode_node **bytecode)
1501 {
1502         _lttng_enabler_attach_filter_bytecode(
1503                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1504
1505         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1506         return 0;
1507 }
1508
1509 static
1510 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1511                 struct lttng_ust_excluder_node **excluder)
1512 {
1513         (*excluder)->enabler = enabler;
1514         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1515         /* Take ownership of excluder */
1516         *excluder = NULL;
1517 }
1518
1519 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1520                 struct lttng_ust_excluder_node **excluder)
1521 {
1522         _lttng_enabler_attach_exclusion(
1523                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1524
1525         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1526         return 0;
1527 }
1528
1529 int lttng_event_notifier_enabler_enable(
1530                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1531 {
1532         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1533         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1534
1535         return 0;
1536 }
1537
1538 int lttng_event_notifier_enabler_disable(
1539                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1540 {
1541         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1542         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1543
1544         return 0;
1545 }
1546
1547 int lttng_event_notifier_enabler_attach_filter_bytecode(
1548                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1549                 struct lttng_ust_bytecode_node **bytecode)
1550 {
1551         _lttng_enabler_attach_filter_bytecode(
1552                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1553                 bytecode);
1554
1555         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1556         return 0;
1557 }
1558
1559 int lttng_event_notifier_enabler_attach_capture_bytecode(
1560                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1561                 struct lttng_ust_bytecode_node **bytecode)
1562 {
1563         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1564                         event_notifier_enabler);
1565         cds_list_add_tail(&(*bytecode)->node,
1566                         &event_notifier_enabler->capture_bytecode_head);
1567         /* Take ownership of bytecode */
1568         *bytecode = NULL;
1569         event_notifier_enabler->num_captures++;
1570
1571         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1572         return 0;
1573 }
1574
1575 int lttng_event_notifier_enabler_attach_exclusion(
1576                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1577                 struct lttng_ust_excluder_node **excluder)
1578 {
1579         _lttng_enabler_attach_exclusion(
1580                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1581                 excluder);
1582
1583         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1584         return 0;
1585 }
1586
1587 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1588                 union lttng_ust_abi_args *uargs,
1589                 struct lttng_ust_ctx **ctx, struct lttng_ust_session *session)
1590 {
1591         /*
1592          * We cannot attach a context after trace has been started for a
1593          * session because the metadata does not allow expressing this
1594          * information outside of the original channel scope.
1595          */
1596         if (session->priv->been_active)
1597                 return -EPERM;
1598
1599         switch (context_param->ctx) {
1600         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1601                 return lttng_add_pthread_id_to_ctx(ctx);
1602         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1603         {
1604                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1605
1606                 perf_ctx_param = &context_param->u.perf_counter;
1607                 return lttng_add_perf_counter_to_ctx(
1608                         perf_ctx_param->type,
1609                         perf_ctx_param->config,
1610                         perf_ctx_param->name,
1611                         ctx);
1612         }
1613         case LTTNG_UST_ABI_CONTEXT_VTID:
1614                 return lttng_add_vtid_to_ctx(ctx);
1615         case LTTNG_UST_ABI_CONTEXT_VPID:
1616                 return lttng_add_vpid_to_ctx(ctx);
1617         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1618                 return lttng_add_procname_to_ctx(ctx);
1619         case LTTNG_UST_ABI_CONTEXT_IP:
1620                 return lttng_add_ip_to_ctx(ctx);
1621         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1622                 return lttng_add_cpu_id_to_ctx(ctx);
1623         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1624                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1625                         ctx);
1626         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1627                 return lttng_add_cgroup_ns_to_ctx(ctx);
1628         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1629                 return lttng_add_ipc_ns_to_ctx(ctx);
1630         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1631                 return lttng_add_mnt_ns_to_ctx(ctx);
1632         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1633                 return lttng_add_net_ns_to_ctx(ctx);
1634         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1635                 return lttng_add_pid_ns_to_ctx(ctx);
1636         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1637                 return lttng_add_time_ns_to_ctx(ctx);
1638         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1639                 return lttng_add_user_ns_to_ctx(ctx);
1640         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1641                 return lttng_add_uts_ns_to_ctx(ctx);
1642         case LTTNG_UST_ABI_CONTEXT_VUID:
1643                 return lttng_add_vuid_to_ctx(ctx);
1644         case LTTNG_UST_ABI_CONTEXT_VEUID:
1645                 return lttng_add_veuid_to_ctx(ctx);
1646         case LTTNG_UST_ABI_CONTEXT_VSUID:
1647                 return lttng_add_vsuid_to_ctx(ctx);
1648         case LTTNG_UST_ABI_CONTEXT_VGID:
1649                 return lttng_add_vgid_to_ctx(ctx);
1650         case LTTNG_UST_ABI_CONTEXT_VEGID:
1651                 return lttng_add_vegid_to_ctx(ctx);
1652         case LTTNG_UST_ABI_CONTEXT_VSGID:
1653                 return lttng_add_vsgid_to_ctx(ctx);
1654         default:
1655                 return -EINVAL;
1656         }
1657 }
1658
1659 int lttng_event_enabler_attach_context(
1660                 struct lttng_event_enabler *enabler __attribute__((unused)),
1661                 struct lttng_ust_abi_context *context_param __attribute__((unused)))
1662 {
1663         return -ENOSYS;
1664 }
1665
1666 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1667 {
1668         if (!event_enabler) {
1669                 return;
1670         }
1671         cds_list_del(&event_enabler->node);
1672
1673         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1674
1675         lttng_destroy_context(event_enabler->ctx);
1676         free(event_enabler);
1677 }
1678
1679 /*
1680  * lttng_session_sync_event_enablers should be called just before starting a
1681  * session.
1682  */
1683 static
1684 void lttng_session_sync_event_enablers(struct lttng_ust_session *session)
1685 {
1686         struct lttng_event_enabler *event_enabler;
1687         struct lttng_ust_event_recorder_private *event_recorder_priv;
1688
1689         cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
1690                 lttng_event_enabler_ref_event_recorders(event_enabler);
1691         /*
1692          * For each event, if at least one of its enablers is enabled,
1693          * and its channel and session transient states are enabled, we
1694          * enable the event, else we disable it.
1695          */
1696         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1697                 struct lttng_enabler_ref *enabler_ref;
1698                 struct lttng_ust_bytecode_runtime *runtime;
1699                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1700                 int nr_filters = 0;
1701
1702                 /* Enable events */
1703                 cds_list_for_each_entry(enabler_ref,
1704                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1705                         if (enabler_ref->ref->enabled) {
1706                                 enabled = 1;
1707                                 break;
1708                         }
1709                 }
1710                 /*
1711                  * Enabled state is based on union of enablers, with
1712                  * intesection of session and channel transient enable
1713                  * states.
1714                  */
1715                 enabled = enabled && session->priv->tstate && event_recorder_priv->pub->chan->priv->parent.tstate;
1716
1717                 CMM_STORE_SHARED(event_recorder_priv->pub->parent->enabled, enabled);
1718                 /*
1719                  * Sync tracepoint registration with event enabled
1720                  * state.
1721                  */
1722                 if (enabled) {
1723                         if (!event_recorder_priv->parent.registered)
1724                                 register_event(event_recorder_priv->parent.pub);
1725                 } else {
1726                         if (event_recorder_priv->parent.registered)
1727                                 unregister_event(event_recorder_priv->parent.pub);
1728                 }
1729
1730                 /* Check if has enablers without bytecode enabled */
1731                 cds_list_for_each_entry(enabler_ref,
1732                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1733                         if (enabler_ref->ref->enabled
1734                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1735                                 has_enablers_without_filter_bytecode = 1;
1736                                 break;
1737                         }
1738                 }
1739                 event_recorder_priv->parent.has_enablers_without_filter_bytecode =
1740                         has_enablers_without_filter_bytecode;
1741
1742                 /* Enable filters */
1743                 cds_list_for_each_entry(runtime,
1744                                 &event_recorder_priv->parent.filter_bytecode_runtime_head, node) {
1745                         lttng_bytecode_sync_state(runtime);
1746                         nr_filters++;
1747                 }
1748                 CMM_STORE_SHARED(event_recorder_priv->parent.pub->eval_filter,
1749                         !(has_enablers_without_filter_bytecode || !nr_filters));
1750         }
1751         lttng_ust_tp_probe_prune_release_queue();
1752 }
1753
1754 /* Support for event notifier is introduced by probe provider major version 2. */
1755 static
1756 bool lttng_ust_probe_supports_event_notifier(const struct lttng_ust_probe_desc *probe_desc)
1757 {
1758         return probe_desc->major >= 2;
1759 }
1760
1761 static
1762 void lttng_create_event_notifier_if_missing(
1763                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1764 {
1765         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1766         struct lttng_ust_registered_probe *reg_probe;
1767         struct cds_list_head *probe_list;
1768         int i;
1769
1770         probe_list = lttng_get_probe_list_head();
1771
1772         cds_list_for_each_entry(reg_probe, probe_list, head) {
1773                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1774
1775                 for (i = 0; i < probe_desc->nr_events; i++) {
1776                         int ret;
1777                         bool found = false;
1778                         const struct lttng_ust_event_desc *desc;
1779                         struct lttng_ust_event_notifier_private *event_notifier_priv;
1780                         struct cds_hlist_head *head;
1781                         struct cds_hlist_node *node;
1782
1783                         desc = probe_desc->event_desc[i];
1784
1785                         if (!lttng_desc_match_enabler(desc,
1786                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1787                                 continue;
1788
1789                         /*
1790                          * Given the current event_notifier group, get the bucket that
1791                          * the target event_notifier would be if it was already
1792                          * created.
1793                          */
1794                         head = borrow_hash_table_bucket(
1795                                 event_notifier_group->event_notifiers_ht.table,
1796                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1797
1798                         cds_hlist_for_each_entry(event_notifier_priv, node, head, hlist) {
1799                                 /*
1800                                  * Check if event_notifier already exists by checking
1801                                  * if the event_notifier and enabler share the same
1802                                  * description and id.
1803                                  */
1804                                 if (event_notifier_priv->parent.desc == desc &&
1805                                                 event_notifier_priv->parent.user_token == event_notifier_enabler->user_token) {
1806                                         found = true;
1807                                         break;
1808                                 }
1809                         }
1810
1811                         if (found)
1812                                 continue;
1813
1814                         /* Check that the probe supports event notifiers, else report the error. */
1815                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1816                                 ERR("Probe \"%s\" contains event \"%s:%s\" which matches an enabled event notifier, "
1817                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1818                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1819                                         "this event will not generate any notification.",
1820                                         probe_desc->provider_name,
1821                                         probe_desc->provider_name, desc->event_name,
1822                                         probe_desc->major,
1823                                         probe_desc->minor);
1824                                 continue;
1825                         }
1826                         /*
1827                          * We need to create a event_notifier for this event probe.
1828                          */
1829                         ret = lttng_event_notifier_create(desc,
1830                                 event_notifier_enabler->user_token,
1831                                 event_notifier_enabler->error_counter_index,
1832                                 event_notifier_group);
1833                         if (ret) {
1834                                 DBG("Unable to create event_notifier \"%s:%s\", error %d\n",
1835                                         probe_desc->provider_name,
1836                                         probe_desc->event_desc[i]->event_name, ret);
1837                         }
1838                 }
1839         }
1840 }
1841
1842 /*
1843  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1844  */
1845 static
1846 int lttng_event_notifier_enabler_ref_event_notifiers(
1847                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1848 {
1849         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1850         struct lttng_ust_event_notifier_private *event_notifier_priv;
1851
1852          /*
1853           * Only try to create event_notifiers for enablers that are enabled, the user
1854           * might still be attaching filter or exclusion to the
1855           * event_notifier_enabler.
1856           */
1857         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1858                 goto end;
1859
1860         /* First, ensure that probe event_notifiers are created for this enabler. */
1861         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1862
1863         /* Link the created event_notifier with its associated enabler. */
1864         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1865                 struct lttng_enabler_ref *enabler_ref;
1866
1867                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier_priv->pub))
1868                         continue;
1869
1870                 enabler_ref = lttng_enabler_ref(&event_notifier_priv->parent.enablers_ref_head,
1871                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1872                 if (!enabler_ref) {
1873                         /*
1874                          * If no backward ref, create it.
1875                          * Add backward ref from event_notifier to enabler.
1876                          */
1877                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1878                         if (!enabler_ref)
1879                                 return -ENOMEM;
1880
1881                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1882                                 event_notifier_enabler);
1883                         cds_list_add(&enabler_ref->node,
1884                                 &event_notifier_priv->parent.enablers_ref_head);
1885                 }
1886
1887                 /*
1888                  * Link filter bytecodes if not linked yet.
1889                  */
1890                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1891                         &event_notifier_group->ctx,
1892                         &event_notifier_priv->parent.filter_bytecode_runtime_head,
1893                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1894
1895                 /*
1896                  * Link capture bytecodes if not linked yet.
1897                  */
1898                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1899                         &event_notifier_group->ctx, &event_notifier_priv->capture_bytecode_runtime_head,
1900                         &event_notifier_enabler->capture_bytecode_head);
1901
1902                 event_notifier_priv->num_captures = event_notifier_enabler->num_captures;
1903         }
1904 end:
1905         return 0;
1906 }
1907
1908 static
1909 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1910 {
1911         struct lttng_event_notifier_enabler *event_notifier_enabler;
1912         struct lttng_ust_event_notifier_private *event_notifier_priv;
1913
1914         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1915                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1916
1917         /*
1918          * For each event_notifier, if at least one of its enablers is enabled,
1919          * we enable the event_notifier, else we disable it.
1920          */
1921         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1922                 struct lttng_enabler_ref *enabler_ref;
1923                 struct lttng_ust_bytecode_runtime *runtime;
1924                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1925                 int nr_filters = 0, nr_captures = 0;
1926
1927                 /* Enable event_notifiers */
1928                 cds_list_for_each_entry(enabler_ref,
1929                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1930                         if (enabler_ref->ref->enabled) {
1931                                 enabled = 1;
1932                                 break;
1933                         }
1934                 }
1935
1936                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1937                 /*
1938                  * Sync tracepoint registration with event_notifier enabled
1939                  * state.
1940                  */
1941                 if (enabled) {
1942                         if (!event_notifier_priv->parent.registered)
1943                                 register_event(event_notifier_priv->parent.pub);
1944                 } else {
1945                         if (event_notifier_priv->parent.registered)
1946                                 unregister_event(event_notifier_priv->parent.pub);
1947                 }
1948
1949                 /* Check if has enablers without bytecode enabled */
1950                 cds_list_for_each_entry(enabler_ref,
1951                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1952                         if (enabler_ref->ref->enabled
1953                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1954                                 has_enablers_without_filter_bytecode = 1;
1955                                 break;
1956                         }
1957                 }
1958                 event_notifier_priv->parent.has_enablers_without_filter_bytecode =
1959                         has_enablers_without_filter_bytecode;
1960
1961                 /* Enable filters */
1962                 cds_list_for_each_entry(runtime,
1963                                 &event_notifier_priv->parent.filter_bytecode_runtime_head, node) {
1964                         lttng_bytecode_sync_state(runtime);
1965                         nr_filters++;
1966                 }
1967                 CMM_STORE_SHARED(event_notifier_priv->parent.pub->eval_filter,
1968                         !(has_enablers_without_filter_bytecode || !nr_filters));
1969
1970                 /* Enable captures. */
1971                 cds_list_for_each_entry(runtime,
1972                                 &event_notifier_priv->capture_bytecode_runtime_head, node) {
1973                         lttng_bytecode_sync_state(runtime);
1974                         nr_captures++;
1975                 }
1976                 CMM_STORE_SHARED(event_notifier_priv->pub->eval_capture,
1977                                 !!nr_captures);
1978         }
1979         lttng_ust_tp_probe_prune_release_queue();
1980 }
1981
1982 /*
1983  * Apply enablers to session events, adding events to session if need
1984  * be. It is required after each modification applied to an active
1985  * session, and right before session "start".
1986  * "lazy" sync means we only sync if required.
1987  */
1988 static
1989 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session)
1990 {
1991         /* We can skip if session is not active */
1992         if (!session->active)
1993                 return;
1994         lttng_session_sync_event_enablers(session);
1995 }
1996
1997 /*
1998  * Update all sessions with the given app context.
1999  * Called with ust lock held.
2000  * This is invoked when an application context gets loaded/unloaded. It
2001  * ensures the context callbacks are in sync with the application
2002  * context (either app context callbacks, or dummy callbacks).
2003  */
2004 void lttng_ust_context_set_session_provider(const char *name,
2005                 size_t (*get_size)(void *priv, size_t offset),
2006                 void (*record)(void *priv, struct lttng_ust_lib_ring_buffer_ctx *ctx,
2007                         struct lttng_ust_channel_buffer *chan),
2008                 void (*get_value)(void *priv, struct lttng_ust_ctx_value *value),
2009                 void *priv)
2010 {
2011         struct lttng_ust_session_private *session_priv;
2012
2013         cds_list_for_each_entry(session_priv, &sessions, node) {
2014                 struct lttng_ust_channel_buffer_private *chan;
2015                 struct lttng_ust_event_recorder_private *event_recorder_priv;
2016                 int ret;
2017
2018                 ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
2019                                 name, get_size, record, get_value, priv);
2020                 if (ret)
2021                         abort();
2022                 cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
2023                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
2024                                         name, get_size, record, get_value, priv);
2025                         if (ret)
2026                                 abort();
2027                 }
2028                 cds_list_for_each_entry(event_recorder_priv, &session_priv->events_head, node) {
2029                         ret = lttng_ust_context_set_provider_rcu(&event_recorder_priv->ctx,
2030                                         name, get_size, record, get_value, priv);
2031                         if (ret)
2032                                 abort();
2033                 }
2034         }
2035 }
2036
2037 /*
2038  * Update all event_notifier groups with the given app context.
2039  * Called with ust lock held.
2040  * This is invoked when an application context gets loaded/unloaded. It
2041  * ensures the context callbacks are in sync with the application
2042  * context (either app context callbacks, or dummy callbacks).
2043  */
2044 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
2045                 size_t (*get_size)(void *priv, size_t offset),
2046                 void (*record)(void *priv, struct lttng_ust_lib_ring_buffer_ctx *ctx,
2047                         struct lttng_ust_channel_buffer *chan),
2048                 void (*get_value)(void *priv, struct lttng_ust_ctx_value *value),
2049                 void *priv)
2050 {
2051         struct lttng_event_notifier_group *event_notifier_group;
2052
2053         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2054                 int ret;
2055
2056                 ret = lttng_ust_context_set_provider_rcu(
2057                                 &event_notifier_group->ctx,
2058                                 name, get_size, record, get_value, priv);
2059                 if (ret)
2060                         abort();
2061         }
2062 }
2063
2064 int lttng_ust_session_uuid_validate(struct lttng_ust_session *session,
2065                 unsigned char *uuid)
2066 {
2067         if (!session)
2068                 return 0;
2069         /* Compare UUID with session. */
2070         if (session->priv->uuid_set) {
2071                 if (memcmp(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN)) {
2072                         return -1;
2073                 }
2074         } else {
2075                 memcpy(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
2076                 session->priv->uuid_set = true;
2077         }
2078         return 0;
2079
2080 }