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 "common/ringbuffer/shm.h"
  53 #include "common/ringbuffer/frontend_types.h"
  54 #include "common/ringbuffer/frontend.h"
  55 #include "common/counter/counter.h"
  56 #include "common/jhash.h"
  57 #include <lttng/ust-abi.h>
  58 #include "context-provider-internal.h"
  59
  60 /*
  61  * All operations within this file are called by the communication
  62  * thread, under ust_lock protection.
  63  */
  64
  65 static CDS_LIST_HEAD(sessions);
  66 static CDS_LIST_HEAD(event_notifier_groups);
  67
  68 struct cds_list_head *lttng_get_sessions(void)
  69 {
  70         return &sessions;
  71 }
  72
  73 static void _lttng_event_destroy(struct lttng_ust_event_common *event);
  74 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  75
  76 static
  77 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session);
  78 static
  79 void lttng_session_sync_event_enablers(struct lttng_ust_session *session);
  80 static
  81 void lttng_event_notifier_group_sync_enablers(
  82                 struct lttng_event_notifier_group *event_notifier_group);
  83 static
  84 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  85
  86 bool lttng_ust_validate_event_name(const struct lttng_ust_event_desc *desc)
  87 {
  88         if (strlen(desc->probe_desc->provider_name) + 1 +
  89                         strlen(desc->event_name) >= LTTNG_UST_ABI_SYM_NAME_LEN)
  90                 return false;
  91         return true;
  92 }
  93
  94 void lttng_ust_format_event_name(const struct lttng_ust_event_desc *desc,
  95                 char *name)
  96 {
  97         strcpy(name, desc->probe_desc->provider_name);
  98         strcat(name, ":");
  99         strcat(name, desc->event_name);
 100 }
 101
 102 /*
 103  * Called with ust lock held.
 104  */
 105 int lttng_session_active(void)
 106 {
 107         struct lttng_ust_session_private *iter;
 108
 109         cds_list_for_each_entry(iter, &sessions, node) {
 110                 if (iter->pub->active)
 111                         return 1;
 112         }
 113         return 0;
 114 }
 115
 116 static
 117 int lttng_loglevel_match(int loglevel,
 118                 unsigned int has_loglevel,
 119                 enum lttng_ust_abi_loglevel_type req_type,
 120                 int req_loglevel)
 121 {
 122         if (!has_loglevel)
 123                 loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
 124         switch (req_type) {
 125         case LTTNG_UST_ABI_LOGLEVEL_RANGE:
 126                 if (loglevel <= req_loglevel
 127                                 || (req_loglevel == -1 && loglevel <= LTTNG_UST_TRACEPOINT_LOGLEVEL_DEBUG))
 128                         return 1;
 129                 else
 130                         return 0;
 131         case LTTNG_UST_ABI_LOGLEVEL_SINGLE:
 132                 if (loglevel == req_loglevel
 133                                 || (req_loglevel == -1 && loglevel <= LTTNG_UST_TRACEPOINT_LOGLEVEL_DEBUG))
 134                         return 1;
 135                 else
 136                         return 0;
 137         case LTTNG_UST_ABI_LOGLEVEL_ALL:
 138         default:
 139                 if (loglevel <= LTTNG_UST_TRACEPOINT_LOGLEVEL_DEBUG)
 140                         return 1;
 141                 else
 142                         return 0;
 143         }
 144 }
 145
 146 struct lttng_ust_session *lttng_session_create(void)
 147 {
 148         struct lttng_ust_session *session;
 149         struct lttng_ust_session_private *session_priv;
 150         int i;
 151
 152         session = zmalloc(sizeof(struct lttng_ust_session));
 153         if (!session)
 154                 return NULL;
 155         session->struct_size = sizeof(struct lttng_ust_session);
 156         session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
 157         if (!session_priv) {
 158                 free(session);
 159                 return NULL;
 160         }
 161         session->priv = session_priv;
 162         session_priv->pub = session;
 163         if (lttng_context_init_all(&session->priv->ctx)) {
 164                 free(session_priv);
 165                 free(session);
 166                 return NULL;
 167         }
 168         CDS_INIT_LIST_HEAD(&session->priv->chan_head);
 169         CDS_INIT_LIST_HEAD(&session->priv->events_head);
 170         CDS_INIT_LIST_HEAD(&session->priv->enums_head);
 171         CDS_INIT_LIST_HEAD(&session->priv->enablers_head);
 172         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 173                 CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 174         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 175                 CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
 176         cds_list_add(&session->priv->node, &sessions);
 177         return session;
 178 }
 179
 180 struct lttng_counter *lttng_ust_counter_create(
 181                 const char *counter_transport_name,
 182                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 183 {
 184         struct lttng_counter_transport *counter_transport = NULL;
 185         struct lttng_counter *counter = NULL;
 186
 187         counter_transport = lttng_counter_transport_find(counter_transport_name);
 188         if (!counter_transport)
 189                 goto notransport;
 190         counter = zmalloc(sizeof(struct lttng_counter));
 191         if (!counter)
 192                 goto nomem;
 193
 194         counter->ops = &counter_transport->ops;
 195         counter->transport = counter_transport;
 196
 197         counter->counter = counter->ops->counter_create(
 198                         number_dimensions, dimensions, 0,
 199                         -1, 0, NULL, false);
 200         if (!counter->counter) {
 201                 goto create_error;
 202         }
 203
 204         return counter;
 205
 206 create_error:
 207         free(counter);
 208 nomem:
 209 notransport:
 210         return NULL;
 211 }
 212
 213 static
 214 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 215 {
 216         counter->ops->counter_destroy(counter->counter);
 217         free(counter);
 218 }
 219
 220 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 221 {
 222         struct lttng_event_notifier_group *event_notifier_group;
 223         int i;
 224
 225         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 226         if (!event_notifier_group)
 227                 return NULL;
 228
 229         /* Add all contexts. */
 230         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 231                 free(event_notifier_group);
 232                 return NULL;
 233         }
 234
 235         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 236         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 237         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 238                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 239
 240         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 241
 242         return event_notifier_group;
 243 }
 244
 245 /*
 246  * Only used internally at session destruction.
 247  */
 248 static
 249 void _lttng_channel_unmap(struct lttng_ust_channel_buffer *lttng_chan)
 250 {
 251         struct lttng_ust_ring_buffer_channel *chan;
 252         struct lttng_ust_shm_handle *handle;
 253
 254         cds_list_del(&lttng_chan->priv->node);
 255         lttng_destroy_context(lttng_chan->priv->ctx);
 256         chan = lttng_chan->priv->rb_chan;
 257         handle = chan->handle;
 258         channel_destroy(chan, handle, 0);
 259         free(lttng_chan->parent);
 260         free(lttng_chan->priv);
 261         free(lttng_chan);
 262 }
 263
 264 static
 265 void register_event(struct lttng_ust_event_common *event)
 266 {
 267         int ret;
 268         const struct lttng_ust_event_desc *desc;
 269
 270         assert(event->priv->registered == 0);
 271         desc = event->priv->desc;
 272         ret = lttng_ust_tp_probe_register_queue_release(desc->probe_desc->provider_name,
 273                         desc->event_name,
 274                         desc->probe_callback,
 275                         event, desc->signature);
 276         WARN_ON_ONCE(ret);
 277         if (!ret)
 278                 event->priv->registered = 1;
 279 }
 280
 281 static
 282 void unregister_event(struct lttng_ust_event_common *event)
 283 {
 284         int ret;
 285         const struct lttng_ust_event_desc *desc;
 286
 287         assert(event->priv->registered == 1);
 288         desc = event->priv->desc;
 289         ret = lttng_ust_tp_probe_unregister_queue_release(desc->probe_desc->provider_name,
 290                         desc->event_name,
 291                         desc->probe_callback,
 292                         event);
 293         WARN_ON_ONCE(ret);
 294         if (!ret)
 295                 event->priv->registered = 0;
 296 }
 297
 298 static
 299 void _lttng_event_unregister(struct lttng_ust_event_common *event)
 300 {
 301         if (event->priv->registered)
 302                 unregister_event(event);
 303 }
 304
 305 void lttng_session_destroy(struct lttng_ust_session *session)
 306 {
 307         struct lttng_ust_channel_buffer_private *chan, *tmpchan;
 308         struct lttng_ust_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
 309         struct lttng_enum *_enum, *tmp_enum;
 310         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 311
 312         CMM_ACCESS_ONCE(session->active) = 0;
 313         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
 314                 _lttng_event_unregister(event_recorder_priv->parent.pub);
 315         }
 316         lttng_ust_urcu_synchronize_rcu();       /* Wait for in-flight events to complete */
 317         lttng_ust_tp_probe_prune_release_queue();
 318         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 319                         &session->priv->enablers_head, node)
 320                 lttng_event_enabler_destroy(event_enabler);
 321         cds_list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv,
 322                         &session->priv->events_head, node)
 323                 _lttng_event_destroy(event_recorder_priv->parent.pub);
 324         cds_list_for_each_entry_safe(_enum, tmp_enum,
 325                         &session->priv->enums_head, node)
 326                 _lttng_enum_destroy(_enum);
 327         cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 328                 _lttng_channel_unmap(chan->pub);
 329         cds_list_del(&session->priv->node);
 330         lttng_destroy_context(session->priv->ctx);
 331         free(session->priv);
 332         free(session);
 333 }
 334
 335 void lttng_event_notifier_group_destroy(
 336                 struct lttng_event_notifier_group *event_notifier_group)
 337 {
 338         int close_ret;
 339         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 340         struct lttng_ust_event_notifier_private *event_notifier_priv, *tmpevent_notifier_priv;
 341
 342         if (!event_notifier_group) {
 343                 return;
 344         }
 345
 346         cds_list_for_each_entry(event_notifier_priv,
 347                         &event_notifier_group->event_notifiers_head, node)
 348                 _lttng_event_unregister(event_notifier_priv->parent.pub);
 349
 350         lttng_ust_urcu_synchronize_rcu();
 351
 352         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 353                         &event_notifier_group->enablers_head, node)
 354                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 355
 356         cds_list_for_each_entry_safe(event_notifier_priv, tmpevent_notifier_priv,
 357                         &event_notifier_group->event_notifiers_head, node)
 358                 _lttng_event_destroy(event_notifier_priv->parent.pub);
 359
 360         if (event_notifier_group->error_counter)
 361                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 362
 363         /* Close the notification fd to the listener of event_notifiers. */
 364
 365         lttng_ust_lock_fd_tracker();
 366         close_ret = close(event_notifier_group->notification_fd);
 367         if (!close_ret) {
 368                 lttng_ust_delete_fd_from_tracker(
 369                                 event_notifier_group->notification_fd);
 370         } else {
 371                 PERROR("close");
 372                 abort();
 373         }
 374         lttng_ust_unlock_fd_tracker();
 375
 376         cds_list_del(&event_notifier_group->node);
 377         lttng_destroy_context(event_notifier_group->ctx);
 378         free(event_notifier_group);
 379 }
 380
 381 static
 382 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 383 {
 384         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 385         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 386
 387         if (!enabler) {
 388                 return;
 389         }
 390
 391         /* Destroy filter bytecode */
 392         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 393                         &enabler->filter_bytecode_head, node) {
 394                 free(filter_node);
 395         }
 396
 397         /* Destroy excluders */
 398         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 399                         &enabler->excluder_head, node) {
 400                 free(excluder_node);
 401         }
 402 }
 403
 404  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 405 {
 406         if (!event_notifier_enabler) {
 407                 return;
 408         }
 409
 410         cds_list_del(&event_notifier_enabler->node);
 411
 412         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 413
 414         free(event_notifier_enabler);
 415 }
 416
 417 static
 418 int lttng_enum_create(const struct lttng_ust_enum_desc *desc,
 419                 struct lttng_ust_session *session)
 420 {
 421         const char *enum_name = desc->name;
 422         struct lttng_enum *_enum;
 423         struct cds_hlist_head *head;
 424         int ret = 0;
 425         size_t name_len = strlen(enum_name);
 426         uint32_t hash;
 427         int notify_socket;
 428
 429         /* Check if this enum is already registered for this session. */
 430         hash = jhash(enum_name, name_len, 0);
 431         head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 432
 433         _enum = lttng_ust_enum_get_from_desc(session, desc);
 434         if (_enum) {
 435                 ret = -EEXIST;
 436                 goto exist;
 437         }
 438
 439         notify_socket = lttng_get_notify_socket(session->priv->owner);
 440         if (notify_socket < 0) {
 441                 ret = notify_socket;
 442                 goto socket_error;
 443         }
 444
 445         _enum = zmalloc(sizeof(*_enum));
 446         if (!_enum) {
 447                 ret = -ENOMEM;
 448                 goto cache_error;
 449         }
 450         _enum->session = session;
 451         _enum->desc = desc;
 452
 453         ret = ustcomm_register_enum(notify_socket,
 454                 session->priv->objd,
 455                 enum_name,
 456                 desc->nr_entries,
 457                 desc->entries,
 458                 &_enum->id);
 459         if (ret < 0) {
 460                 DBG("Error (%d) registering enumeration to sessiond", ret);
 461                 goto sessiond_register_error;
 462         }
 463         cds_list_add(&_enum->node, &session->priv->enums_head);
 464         cds_hlist_add_head(&_enum->hlist, head);
 465         return 0;
 466
 467 sessiond_register_error:
 468         free(_enum);
 469 cache_error:
 470 socket_error:
 471 exist:
 472         return ret;
 473 }
 474
 475 static
 476 int lttng_create_enum_check(const struct lttng_ust_type_common *type,
 477                 struct lttng_ust_session *session)
 478 {
 479         switch (type->type) {
 480         case lttng_ust_type_enum:
 481         {
 482                 const struct lttng_ust_enum_desc *enum_desc;
 483                 int ret;
 484
 485                 enum_desc = lttng_ust_get_type_enum(type)->desc;
 486                 ret = lttng_enum_create(enum_desc, session);
 487                 if (ret && ret != -EEXIST) {
 488                         DBG("Unable to create enum error: (%d)", ret);
 489                         return ret;
 490                 }
 491                 break;
 492         }
 493         case lttng_ust_type_dynamic:
 494         {
 495                 const struct lttng_ust_event_field *tag_field_generic;
 496                 const struct lttng_ust_enum_desc *enum_desc;
 497                 int ret;
 498
 499                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 500                 enum_desc = lttng_ust_get_type_enum(tag_field_generic->type)->desc;
 501                 ret = lttng_enum_create(enum_desc, session);
 502                 if (ret && ret != -EEXIST) {
 503                         DBG("Unable to create enum error: (%d)", ret);
 504                         return ret;
 505                 }
 506                 break;
 507         }
 508         default:
 509                 /* TODO: nested types when they become supported. */
 510                 break;
 511         }
 512         return 0;
 513 }
 514
 515 static
 516 int lttng_create_all_event_enums(size_t nr_fields,
 517                 const struct lttng_ust_event_field * const *event_fields,
 518                 struct lttng_ust_session *session)
 519 {
 520         size_t i;
 521         int ret;
 522
 523         /* For each field, ensure enum is part of the session. */
 524         for (i = 0; i < nr_fields; i++) {
 525                 const struct lttng_ust_type_common *type = event_fields[i]->type;
 526
 527                 ret = lttng_create_enum_check(type, session);
 528                 if (ret)
 529                         return ret;
 530         }
 531         return 0;
 532 }
 533
 534 static
 535 int lttng_create_all_ctx_enums(size_t nr_fields,
 536                 struct lttng_ust_ctx_field *ctx_fields,
 537                 struct lttng_ust_session *session)
 538 {
 539         size_t i;
 540         int ret;
 541
 542         /* For each field, ensure enum is part of the session. */
 543         for (i = 0; i < nr_fields; i++) {
 544                 const struct lttng_ust_type_common *type = ctx_fields[i].event_field->type;
 545
 546                 ret = lttng_create_enum_check(type, session);
 547                 if (ret)
 548                         return ret;
 549         }
 550         return 0;
 551 }
 552
 553 /*
 554  * Ensure that a state-dump will be performed for this session at the end
 555  * of the current handle_message().
 556  */
 557 int lttng_session_statedump(struct lttng_ust_session *session)
 558 {
 559         session->priv->statedump_pending = 1;
 560         lttng_ust_sockinfo_session_enabled(session->priv->owner);
 561         return 0;
 562 }
 563
 564 int lttng_session_enable(struct lttng_ust_session *session)
 565 {
 566         int ret = 0;
 567         struct lttng_ust_channel_buffer_private *chan;
 568         int notify_socket;
 569
 570         if (session->active) {
 571                 ret = -EBUSY;
 572                 goto end;
 573         }
 574
 575         notify_socket = lttng_get_notify_socket(session->priv->owner);
 576         if (notify_socket < 0)
 577                 return notify_socket;
 578
 579         /* Set transient enabler state to "enabled" */
 580         session->priv->tstate = 1;
 581
 582         /* We need to sync enablers with session before activation. */
 583         lttng_session_sync_event_enablers(session);
 584
 585         /*
 586          * Snapshot the number of events per channel to know the type of header
 587          * we need to use.
 588          */
 589         cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 590                 struct lttng_ust_ctx *ctx;
 591                 struct lttng_ust_ctx_field *fields = NULL;
 592                 size_t nr_fields = 0;
 593                 uint32_t chan_id;
 594
 595                 /* don't change it if session stop/restart */
 596                 if (chan->header_type)
 597                         continue;
 598                 ctx = chan->ctx;
 599                 if (ctx) {
 600                         nr_fields = ctx->nr_fields;
 601                         fields = ctx->fields;
 602                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 603                                 session);
 604                         if (ret < 0) {
 605                                 DBG("Error (%d) adding enum to session", ret);
 606                                 return ret;
 607                         }
 608                 }
 609                 ret = ustcomm_register_channel(notify_socket,
 610                         session,
 611                         session->priv->objd,
 612                         chan->parent.objd,
 613                         nr_fields,
 614                         fields,
 615                         &chan_id,
 616                         &chan->header_type);
 617                 if (ret) {
 618                         DBG("Error (%d) registering channel to sessiond", ret);
 619                         return ret;
 620                 }
 621                 if (chan_id != chan->id) {
 622                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 623                                 chan_id, chan->id);
 624                         return -EINVAL;
 625                 }
 626         }
 627
 628         /* Set atomically the state to "active" */
 629         CMM_ACCESS_ONCE(session->active) = 1;
 630         CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 631
 632         ret = lttng_session_statedump(session);
 633         if (ret)
 634                 return ret;
 635 end:
 636         return ret;
 637 }
 638
 639 int lttng_session_disable(struct lttng_ust_session *session)
 640 {
 641         int ret = 0;
 642
 643         if (!session->active) {
 644                 ret = -EBUSY;
 645                 goto end;
 646         }
 647         /* Set atomically the state to "inactive" */
 648         CMM_ACCESS_ONCE(session->active) = 0;
 649
 650         /* Set transient enabler state to "disabled" */
 651         session->priv->tstate = 0;
 652         lttng_session_sync_event_enablers(session);
 653 end:
 654         return ret;
 655 }
 656
 657 int lttng_channel_enable(struct lttng_ust_channel_common *lttng_channel)
 658 {
 659         int ret = 0;
 660
 661         if (lttng_channel->enabled) {
 662                 ret = -EBUSY;
 663                 goto end;
 664         }
 665         /* Set transient enabler state to "enabled" */
 666         lttng_channel->priv->tstate = 1;
 667         lttng_session_sync_event_enablers(lttng_channel->session);
 668         /* Set atomically the state to "enabled" */
 669         CMM_ACCESS_ONCE(lttng_channel->enabled) = 1;
 670 end:
 671         return ret;
 672 }
 673
 674 int lttng_channel_disable(struct lttng_ust_channel_common *lttng_channel)
 675 {
 676         int ret = 0;
 677
 678         if (!lttng_channel->enabled) {
 679                 ret = -EBUSY;
 680                 goto end;
 681         }
 682         /* Set atomically the state to "disabled" */
 683         CMM_ACCESS_ONCE(lttng_channel->enabled) = 0;
 684         /* Set transient enabler state to "enabled" */
 685         lttng_channel->priv->tstate = 0;
 686         lttng_session_sync_event_enablers(lttng_channel->session);
 687 end:
 688         return ret;
 689 }
 690
 691 static inline
 692 struct cds_hlist_head *borrow_hash_table_bucket(
 693                 struct cds_hlist_head *hash_table,
 694                 unsigned int hash_table_size,
 695                 const struct lttng_ust_event_desc *desc)
 696 {
 697         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 698         size_t name_len;
 699         uint32_t hash;
 700
 701         lttng_ust_format_event_name(desc, name);
 702         name_len = strlen(name);
 703
 704         hash = jhash(name, name_len, 0);
 705         return &hash_table[hash & (hash_table_size - 1)];
 706 }
 707
 708 /*
 709  * Supports event creation while tracing session is active.
 710  */
 711 static
 712 int lttng_event_recorder_create(const struct lttng_ust_event_desc *desc,
 713                 struct lttng_ust_channel_buffer *chan)
 714 {
 715         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 716         struct lttng_ust_event_recorder *event_recorder;
 717         struct lttng_ust_event_recorder_private *event_recorder_priv;
 718         struct lttng_ust_session *session = chan->parent->session;
 719         struct cds_hlist_head *head;
 720         int ret = 0;
 721         int notify_socket, loglevel;
 722         const char *uri;
 723
 724         head = borrow_hash_table_bucket(chan->parent->session->priv->events_ht.table,
 725                 LTTNG_UST_EVENT_HT_SIZE, desc);
 726
 727         notify_socket = lttng_get_notify_socket(session->priv->owner);
 728         if (notify_socket < 0) {
 729                 ret = notify_socket;
 730                 goto socket_error;
 731         }
 732
 733         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 734                         session);
 735         if (ret < 0) {
 736                 DBG("Error (%d) adding enum to session", ret);
 737                 goto create_enum_error;
 738         }
 739
 740         /*
 741          * Check if loglevel match. Refuse to connect event if not.
 742          */
 743         event_recorder = zmalloc(sizeof(struct lttng_ust_event_recorder));
 744         if (!event_recorder) {
 745                 ret = -ENOMEM;
 746                 goto cache_error;
 747         }
 748         event_recorder->struct_size = sizeof(struct lttng_ust_event_recorder);
 749
 750         event_recorder->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 751         if (!event_recorder->parent) {
 752                 ret = -ENOMEM;
 753                 goto parent_error;
 754         }
 755         event_recorder->parent->struct_size = sizeof(struct lttng_ust_event_common);
 756         event_recorder->parent->type = LTTNG_UST_EVENT_TYPE_RECORDER;
 757         event_recorder->parent->child = event_recorder;
 758
 759         event_recorder_priv = zmalloc(sizeof(struct lttng_ust_event_recorder_private));
 760         if (!event_recorder_priv) {
 761                 ret = -ENOMEM;
 762                 goto priv_error;
 763         }
 764         event_recorder->priv = event_recorder_priv;
 765         event_recorder_priv->pub = event_recorder;
 766         event_recorder->parent->priv = &event_recorder_priv->parent;
 767         event_recorder_priv->parent.pub = event_recorder->parent;
 768
 769         event_recorder->chan = chan;
 770
 771         /* Event will be enabled by enabler sync. */
 772         event_recorder->parent->run_filter = lttng_ust_interpret_event_filter;
 773         event_recorder->parent->enabled = 0;
 774         event_recorder->parent->priv->registered = 0;
 775         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->filter_bytecode_runtime_head);
 776         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 777         event_recorder->parent->priv->desc = desc;
 778
 779         if (desc->loglevel)
 780                 loglevel = *(*desc->loglevel);
 781         else
 782                 loglevel = LTTNG_UST_TRACEPOINT_LOGLEVEL_DEFAULT;
 783         if (desc->model_emf_uri)
 784                 uri = *(desc->model_emf_uri);
 785         else
 786                 uri = NULL;
 787
 788         lttng_ust_format_event_name(desc, name);
 789
 790         /* Fetch event ID from sessiond */
 791         ret = ustcomm_register_event(notify_socket,
 792                 session,
 793                 session->priv->objd,
 794                 chan->priv->parent.objd,
 795                 name,
 796                 loglevel,
 797                 desc->signature,
 798                 desc->nr_fields,
 799                 desc->fields,
 800                 uri,
 801                 &event_recorder->priv->id);
 802         if (ret < 0) {
 803                 DBG("Error (%d) registering event to sessiond", ret);
 804                 goto sessiond_register_error;
 805         }
 806
 807         cds_list_add(&event_recorder_priv->node, &chan->parent->session->priv->events_head);
 808         cds_hlist_add_head(&event_recorder_priv->hlist, head);
 809         return 0;
 810
 811 sessiond_register_error:
 812         free(event_recorder_priv);
 813 priv_error:
 814         free(event_recorder->parent);
 815 parent_error:
 816         free(event_recorder);
 817 cache_error:
 818 create_enum_error:
 819 socket_error:
 820         return ret;
 821 }
 822
 823 static
 824 int lttng_event_notifier_create(const struct lttng_ust_event_desc *desc,
 825                 uint64_t token, uint64_t error_counter_index,
 826                 struct lttng_event_notifier_group *event_notifier_group)
 827 {
 828         struct lttng_ust_event_notifier *event_notifier;
 829         struct lttng_ust_event_notifier_private *event_notifier_priv;
 830         struct cds_hlist_head *head;
 831         int ret = 0;
 832
 833         /*
 834          * Get the hashtable bucket the created lttng_event_notifier object
 835          * should be inserted.
 836          */
 837         head = borrow_hash_table_bucket(
 838                 event_notifier_group->event_notifiers_ht.table,
 839                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 840
 841         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 842         if (!event_notifier) {
 843                 ret = -ENOMEM;
 844                 goto error;
 845         }
 846         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 847
 848         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 849         if (!event_notifier->parent) {
 850                 ret = -ENOMEM;
 851                 goto parent_error;
 852         }
 853         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 854         event_notifier->parent->type = LTTNG_UST_EVENT_TYPE_NOTIFIER;
 855         event_notifier->parent->child = event_notifier;
 856
 857         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 858         if (!event_notifier_priv) {
 859                 ret = -ENOMEM;
 860                 goto priv_error;
 861         }
 862         event_notifier->priv = event_notifier_priv;
 863         event_notifier_priv->pub = event_notifier;
 864         event_notifier->parent->priv = &event_notifier_priv->parent;
 865         event_notifier_priv->parent.pub = event_notifier->parent;
 866
 867         event_notifier_priv->group = event_notifier_group;
 868         event_notifier_priv->parent.user_token = token;
 869         event_notifier_priv->error_counter_index = error_counter_index;
 870
 871         /* Event notifier will be enabled by enabler sync. */
 872         event_notifier->parent->run_filter = lttng_ust_interpret_event_filter;
 873         event_notifier->parent->enabled = 0;
 874         event_notifier_priv->parent.registered = 0;
 875
 876         CDS_INIT_LIST_HEAD(&event_notifier->parent->priv->filter_bytecode_runtime_head);
 877         CDS_INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
 878         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 879         event_notifier_priv->parent.desc = desc;
 880         event_notifier->notification_send = lttng_event_notifier_notification_send;
 881
 882         cds_list_add(&event_notifier_priv->node,
 883                         &event_notifier_group->event_notifiers_head);
 884         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 885
 886         return 0;
 887
 888 priv_error:
 889         free(event_notifier->parent);
 890 parent_error:
 891         free(event_notifier);
 892 error:
 893         return ret;
 894 }
 895
 896 static
 897 int lttng_desc_match_star_glob_enabler(const struct lttng_ust_event_desc *desc,
 898                 struct lttng_enabler *enabler)
 899 {
 900         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 901         int loglevel = 0;
 902         unsigned int has_loglevel = 0;
 903
 904         lttng_ust_format_event_name(desc, name);
 905         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 906         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 907                         name, SIZE_MAX))
 908                 return 0;
 909         if (desc->loglevel) {
 910                 loglevel = *(*desc->loglevel);
 911                 has_loglevel = 1;
 912         }
 913         if (!lttng_loglevel_match(loglevel,
 914                         has_loglevel,
 915                         enabler->event_param.loglevel_type,
 916                         enabler->event_param.loglevel))
 917                 return 0;
 918         return 1;
 919 }
 920
 921 static
 922 int lttng_desc_match_event_enabler(const struct lttng_ust_event_desc *desc,
 923                 struct lttng_enabler *enabler)
 924 {
 925         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 926         int loglevel = 0;
 927         unsigned int has_loglevel = 0;
 928
 929         lttng_ust_format_event_name(desc, name);
 930         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 931         if (strcmp(name, enabler->event_param.name))
 932                 return 0;
 933         if (desc->loglevel) {
 934                 loglevel = *(*desc->loglevel);
 935                 has_loglevel = 1;
 936         }
 937         if (!lttng_loglevel_match(loglevel,
 938                         has_loglevel,
 939                         enabler->event_param.loglevel_type,
 940                         enabler->event_param.loglevel))
 941                 return 0;
 942         return 1;
 943 }
 944
 945 static
 946 int lttng_desc_match_enabler(const struct lttng_ust_event_desc *desc,
 947                 struct lttng_enabler *enabler)
 948 {
 949         switch (enabler->format_type) {
 950         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 951         {
 952                 struct lttng_ust_excluder_node *excluder;
 953
 954                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 955                         return 0;
 956                 }
 957
 958                 /*
 959                  * If the matching event matches with an excluder,
 960                  * return 'does not match'
 961                  */
 962                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 963                         int count;
 964
 965                         for (count = 0; count < excluder->excluder.count; count++) {
 966                                 int len;
 967                                 char *excluder_name;
 968
 969                                 excluder_name = (char *) (excluder->excluder.names)
 970                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
 971                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 972                                 if (len > 0) {
 973                                         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 974
 975                                         lttng_ust_format_event_name(desc, name);
 976                                         if (strutils_star_glob_match(excluder_name, len, name, SIZE_MAX)) {
 977                                                 return 0;
 978                                         }
 979                                 }
 980                         }
 981                 }
 982                 return 1;
 983         }
 984         case LTTNG_ENABLER_FORMAT_EVENT:
 985                 return lttng_desc_match_event_enabler(desc, enabler);
 986         default:
 987                 return -EINVAL;
 988         }
 989 }
 990
 991 static
 992 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 993                 struct lttng_ust_event_recorder *event_recorder)
 994 {
 995         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
 996                         lttng_event_enabler_as_enabler(event_enabler))
 997                         && event_recorder->chan == event_enabler->chan)
 998                 return 1;
 999         else
1000                 return 0;
1001 }
1002
1003 static
1004 int lttng_event_notifier_enabler_match_event_notifier(
1005                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1006                 struct lttng_ust_event_notifier *event_notifier)
1007 {
1008         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
1009                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1010
1011         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
1012                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
1013                 return 1;
1014         else
1015                 return 0;
1016 }
1017
1018 static
1019 struct lttng_enabler_ref *lttng_enabler_ref(
1020                 struct cds_list_head *enabler_ref_list,
1021                 struct lttng_enabler *enabler)
1022 {
1023         struct lttng_enabler_ref *enabler_ref;
1024
1025         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1026                 if (enabler_ref->ref == enabler)
1027                         return enabler_ref;
1028         }
1029         return NULL;
1030 }
1031
1032 /*
1033  * Create struct lttng_event if it is missing and present in the list of
1034  * tracepoint probes.
1035  */
1036 static
1037 void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_enabler)
1038 {
1039         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1040         struct lttng_ust_registered_probe *reg_probe;
1041         const struct lttng_ust_event_desc *desc;
1042         struct lttng_ust_event_recorder_private *event_recorder_priv;
1043         int i;
1044         struct cds_list_head *probe_list;
1045
1046         probe_list = lttng_get_probe_list_head();
1047         /*
1048          * For each probe event, if we find that a probe event matches
1049          * our enabler, create an associated lttng_event if not
1050          * already present.
1051          */
1052         cds_list_for_each_entry(reg_probe, probe_list, head) {
1053                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1054
1055                 for (i = 0; i < probe_desc->nr_events; i++) {
1056                         int ret;
1057                         bool found = false;
1058                         struct cds_hlist_head *head;
1059                         struct cds_hlist_node *node;
1060
1061                         desc = probe_desc->event_desc[i];
1062                         if (!lttng_desc_match_enabler(desc,
1063                                         lttng_event_enabler_as_enabler(event_enabler)))
1064                                 continue;
1065
1066                         head = borrow_hash_table_bucket(
1067                                 session->priv->events_ht.table,
1068                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1069
1070                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1071                                 if (event_recorder_priv->parent.desc == desc
1072                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1073                                         found = true;
1074                                         break;
1075                                 }
1076                         }
1077                         if (found)
1078                                 continue;
1079
1080                         /*
1081                          * We need to create an event for this
1082                          * event probe.
1083                          */
1084                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1085                                         event_enabler->chan);
1086                         if (ret) {
1087                                 DBG("Unable to create event \"%s:%s\", error %d\n",
1088                                         probe_desc->provider_name,
1089                                         probe_desc->event_desc[i]->event_name, ret);
1090                         }
1091                 }
1092         }
1093 }
1094
1095 static
1096 void probe_provider_event_for_each(const struct lttng_ust_probe_desc *provider_desc,
1097                 void (*event_func)(struct lttng_ust_event_common *event))
1098 {
1099         struct cds_hlist_node *node, *tmp_node;
1100         struct cds_list_head *sessionsp;
1101         unsigned int i;
1102
1103         /* Get handle on list of sessions. */
1104         sessionsp = lttng_get_sessions();
1105
1106         /*
1107          * Iterate over all events in the probe provider descriptions and
1108          * sessions to queue the unregistration of the events.
1109          */
1110         for (i = 0; i < provider_desc->nr_events; i++) {
1111                 const struct lttng_ust_event_desc *event_desc;
1112                 struct lttng_event_notifier_group *event_notifier_group;
1113                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1114                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1115                 struct lttng_ust_session_private *session_priv;
1116                 struct cds_hlist_head *head;
1117
1118                 event_desc = provider_desc->event_desc[i];
1119
1120                 /*
1121                  * Iterate over all session to find the current event
1122                  * description.
1123                  */
1124                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1125                         /*
1126                          * Get the list of events in the hashtable bucket and
1127                          * iterate to find the event matching this descriptor.
1128                          */
1129                         head = borrow_hash_table_bucket(
1130                                 session_priv->events_ht.table,
1131                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1132
1133                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1134                                 if (event_desc == event_recorder_priv->parent.desc) {
1135                                         event_func(event_recorder_priv->parent.pub);
1136                                         break;
1137                                 }
1138                         }
1139                 }
1140
1141                 /*
1142                  * Iterate over all event_notifier groups to find the current event
1143                  * description.
1144                  */
1145                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1146                         /*
1147                          * Get the list of event_notifiers in the hashtable bucket and
1148                          * iterate to find the event_notifier matching this
1149                          * descriptor.
1150                          */
1151                         head = borrow_hash_table_bucket(
1152                                 event_notifier_group->event_notifiers_ht.table,
1153                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1154
1155                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1156                                 if (event_desc == event_notifier_priv->parent.desc) {
1157                                         event_func(event_notifier_priv->parent.pub);
1158                                         break;
1159                                 }
1160                         }
1161                 }
1162         }
1163 }
1164
1165 static
1166 void _event_enum_destroy(struct lttng_ust_event_common *event)
1167 {
1168
1169         switch (event->type) {
1170         case LTTNG_UST_EVENT_TYPE_RECORDER:
1171         {
1172                 struct lttng_ust_event_recorder *event_recorder = event->child;
1173                 struct lttng_ust_session *session = event_recorder->chan->parent->session;
1174                 unsigned int i;
1175
1176                 /* Destroy enums of the current event. */
1177                 for (i = 0; i < event_recorder->parent->priv->desc->nr_fields; i++) {
1178                         const struct lttng_ust_enum_desc *enum_desc;
1179                         const struct lttng_ust_event_field *field;
1180                         struct lttng_enum *curr_enum;
1181
1182                         field = event_recorder->parent->priv->desc->fields[i];
1183                         switch (field->type->type) {
1184                         case lttng_ust_type_enum:
1185                                 enum_desc = lttng_ust_get_type_enum(field->type)->desc;
1186                                 break;
1187                         default:
1188                                 continue;
1189                         }
1190
1191                         curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1192                         if (curr_enum) {
1193                                 _lttng_enum_destroy(curr_enum);
1194                         }
1195                 }
1196                 break;
1197         }
1198         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1199                 break;
1200         default:
1201                 abort();
1202         }
1203         /* Destroy event. */
1204         _lttng_event_destroy(event);
1205 }
1206
1207 /*
1208  * Iterate over all the UST sessions to unregister and destroy all probes from
1209  * the probe provider descriptor received as argument. Must me called with the
1210  * ust_lock held.
1211  */
1212 void lttng_probe_provider_unregister_events(
1213                 const struct lttng_ust_probe_desc *provider_desc)
1214 {
1215         /*
1216          * Iterate over all events in the probe provider descriptions and sessions
1217          * to queue the unregistration of the events.
1218          */
1219         probe_provider_event_for_each(provider_desc, _lttng_event_unregister);
1220
1221         /* Wait for grace period. */
1222         lttng_ust_urcu_synchronize_rcu();
1223         /* Prune the unregistration queue. */
1224         lttng_ust_tp_probe_prune_release_queue();
1225
1226         /*
1227          * It is now safe to destroy the events and remove them from the event list
1228          * and hashtables.
1229          */
1230         probe_provider_event_for_each(provider_desc, _event_enum_destroy);
1231 }
1232
1233 /*
1234  * Create events associated with an event enabler (if not already present),
1235  * and add backward reference from the event to the enabler.
1236  */
1237 static
1238 int lttng_event_enabler_ref_event_recorders(struct lttng_event_enabler *event_enabler)
1239 {
1240         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1241         struct lttng_ust_event_recorder_private *event_recorder_priv;
1242
1243         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1244                 goto end;
1245
1246         /* First ensure that probe events are created for this enabler. */
1247         lttng_create_event_recorder_if_missing(event_enabler);
1248
1249         /* For each event matching enabler in session event list. */
1250         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1251                 struct lttng_enabler_ref *enabler_ref;
1252
1253                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1254                         continue;
1255
1256                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1257                         lttng_event_enabler_as_enabler(event_enabler));
1258                 if (!enabler_ref) {
1259                         /*
1260                          * If no backward ref, create it.
1261                          * Add backward ref from event to enabler.
1262                          */
1263                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1264                         if (!enabler_ref)
1265                                 return -ENOMEM;
1266                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1267                                 event_enabler);
1268                         cds_list_add(&enabler_ref->node,
1269                                 &event_recorder_priv->parent.enablers_ref_head);
1270                 }
1271
1272                 /*
1273                  * Link filter bytecodes if not linked yet.
1274                  */
1275                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1276                         &session->priv->ctx,
1277                         &event_recorder_priv->parent.filter_bytecode_runtime_head,
1278                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1279
1280                 /* TODO: merge event context. */
1281         }
1282 end:
1283         return 0;
1284 }
1285
1286 /*
1287  * Called at library load: connect the probe on all enablers matching
1288  * this event.
1289  * Called with session mutex held.
1290  */
1291 int lttng_fix_pending_events(void)
1292 {
1293         struct lttng_ust_session_private *session_priv;
1294
1295         cds_list_for_each_entry(session_priv, &sessions, node) {
1296                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1297         }
1298         return 0;
1299 }
1300
1301 int lttng_fix_pending_event_notifiers(void)
1302 {
1303         struct lttng_event_notifier_group *event_notifier_group;
1304
1305         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1306                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1307         }
1308         return 0;
1309 }
1310
1311 /*
1312  * For each session of the owner thread, execute pending statedump.
1313  * Only dump state for the sessions owned by the caller thread, because
1314  * we don't keep ust_lock across the entire iteration.
1315  */
1316 void lttng_handle_pending_statedump(void *owner)
1317 {
1318         struct lttng_ust_session_private *session_priv;
1319
1320         /* Execute state dump */
1321         do_lttng_ust_statedump(owner);
1322
1323         /* Clear pending state dump */
1324         if (ust_lock()) {
1325                 goto end;
1326         }
1327         cds_list_for_each_entry(session_priv, &sessions, node) {
1328                 if (session_priv->owner != owner)
1329                         continue;
1330                 if (!session_priv->statedump_pending)
1331                         continue;
1332                 session_priv->statedump_pending = 0;
1333         }
1334 end:
1335         ust_unlock();
1336         return;
1337 }
1338
1339 static
1340 void _lttng_event_destroy(struct lttng_ust_event_common *event)
1341 {
1342         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1343
1344         lttng_free_event_filter_runtime(event);
1345         /* Free event enabler refs */
1346         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1347                         &event->priv->enablers_ref_head, node)
1348                 free(enabler_ref);
1349
1350         switch (event->type) {
1351         case LTTNG_UST_EVENT_TYPE_RECORDER:
1352         {
1353                 struct lttng_ust_event_recorder *event_recorder = event->child;
1354
1355                 /* Remove from event list. */
1356                 cds_list_del(&event_recorder->priv->node);
1357                 /* Remove from event hash table. */
1358                 cds_hlist_del(&event_recorder->priv->hlist);
1359
1360                 lttng_destroy_context(event_recorder->priv->ctx);
1361                 free(event_recorder->parent);
1362                 free(event_recorder->priv);
1363                 free(event_recorder);
1364                 break;
1365         }
1366         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1367         {
1368                 struct lttng_ust_event_notifier *event_notifier = event->child;
1369
1370                 /* Remove from event list. */
1371                 cds_list_del(&event_notifier->priv->node);
1372                 /* Remove from event hash table. */
1373                 cds_hlist_del(&event_notifier->priv->hlist);
1374
1375                 free(event_notifier->priv);
1376                 free(event_notifier->parent);
1377                 free(event_notifier);
1378                 break;
1379         }
1380         default:
1381                 abort();
1382         }
1383 }
1384
1385 static
1386 void _lttng_enum_destroy(struct lttng_enum *_enum)
1387 {
1388         cds_list_del(&_enum->node);
1389         cds_hlist_del(&_enum->hlist);
1390         free(_enum);
1391 }
1392
1393 void lttng_ust_abi_events_exit(void)
1394 {
1395         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1396
1397         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1398                 lttng_session_destroy(session_priv->pub);
1399 }
1400
1401 /*
1402  * Enabler management.
1403  */
1404 struct lttng_event_enabler *lttng_event_enabler_create(
1405                 enum lttng_enabler_format_type format_type,
1406                 struct lttng_ust_abi_event *event_param,
1407                 struct lttng_ust_channel_buffer *chan)
1408 {
1409         struct lttng_event_enabler *event_enabler;
1410
1411         event_enabler = zmalloc(sizeof(*event_enabler));
1412         if (!event_enabler)
1413                 return NULL;
1414         event_enabler->base.format_type = format_type;
1415         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1416         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1417         memcpy(&event_enabler->base.event_param, event_param,
1418                 sizeof(event_enabler->base.event_param));
1419         event_enabler->chan = chan;
1420         /* ctx left NULL */
1421         event_enabler->base.enabled = 0;
1422         cds_list_add(&event_enabler->node, &event_enabler->chan->parent->session->priv->enablers_head);
1423         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1424
1425         return event_enabler;
1426 }
1427
1428 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1429                 struct lttng_event_notifier_group *event_notifier_group,
1430                 enum lttng_enabler_format_type format_type,
1431                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1432 {
1433         struct lttng_event_notifier_enabler *event_notifier_enabler;
1434
1435         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1436         if (!event_notifier_enabler)
1437                 return NULL;
1438         event_notifier_enabler->base.format_type = format_type;
1439         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1440         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1441         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1442
1443         event_notifier_enabler->user_token = event_notifier_param->event.token;
1444         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1445         event_notifier_enabler->num_captures = 0;
1446
1447         memcpy(&event_notifier_enabler->base.event_param.name,
1448                 event_notifier_param->event.name,
1449                 sizeof(event_notifier_enabler->base.event_param.name));
1450         event_notifier_enabler->base.event_param.instrumentation =
1451                 event_notifier_param->event.instrumentation;
1452         event_notifier_enabler->base.event_param.loglevel =
1453                 event_notifier_param->event.loglevel;
1454         event_notifier_enabler->base.event_param.loglevel_type =
1455                 event_notifier_param->event.loglevel_type;
1456
1457         event_notifier_enabler->base.enabled = 0;
1458         event_notifier_enabler->group = event_notifier_group;
1459
1460         cds_list_add(&event_notifier_enabler->node,
1461                         &event_notifier_group->enablers_head);
1462
1463         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1464
1465         return event_notifier_enabler;
1466 }
1467
1468 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1469 {
1470         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1471         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1472
1473         return 0;
1474 }
1475
1476 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1477 {
1478         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1479         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1480
1481         return 0;
1482 }
1483
1484 static
1485 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1486                 struct lttng_ust_bytecode_node **bytecode)
1487 {
1488         (*bytecode)->enabler = enabler;
1489         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1490         /* Take ownership of bytecode */
1491         *bytecode = NULL;
1492 }
1493
1494 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1495                 struct lttng_ust_bytecode_node **bytecode)
1496 {
1497         _lttng_enabler_attach_filter_bytecode(
1498                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1499
1500         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1501         return 0;
1502 }
1503
1504 static
1505 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1506                 struct lttng_ust_excluder_node **excluder)
1507 {
1508         (*excluder)->enabler = enabler;
1509         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1510         /* Take ownership of excluder */
1511         *excluder = NULL;
1512 }
1513
1514 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1515                 struct lttng_ust_excluder_node **excluder)
1516 {
1517         _lttng_enabler_attach_exclusion(
1518                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1519
1520         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1521         return 0;
1522 }
1523
1524 int lttng_event_notifier_enabler_enable(
1525                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1526 {
1527         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1528         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1529
1530         return 0;
1531 }
1532
1533 int lttng_event_notifier_enabler_disable(
1534                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1535 {
1536         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1537         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1538
1539         return 0;
1540 }
1541
1542 int lttng_event_notifier_enabler_attach_filter_bytecode(
1543                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1544                 struct lttng_ust_bytecode_node **bytecode)
1545 {
1546         _lttng_enabler_attach_filter_bytecode(
1547                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1548                 bytecode);
1549
1550         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1551         return 0;
1552 }
1553
1554 int lttng_event_notifier_enabler_attach_capture_bytecode(
1555                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1556                 struct lttng_ust_bytecode_node **bytecode)
1557 {
1558         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1559                         event_notifier_enabler);
1560         cds_list_add_tail(&(*bytecode)->node,
1561                         &event_notifier_enabler->capture_bytecode_head);
1562         /* Take ownership of bytecode */
1563         *bytecode = NULL;
1564         event_notifier_enabler->num_captures++;
1565
1566         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1567         return 0;
1568 }
1569
1570 int lttng_event_notifier_enabler_attach_exclusion(
1571                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1572                 struct lttng_ust_excluder_node **excluder)
1573 {
1574         _lttng_enabler_attach_exclusion(
1575                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1576                 excluder);
1577
1578         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1579         return 0;
1580 }
1581
1582 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1583                 union lttng_ust_abi_args *uargs,
1584                 struct lttng_ust_ctx **ctx, struct lttng_ust_session *session)
1585 {
1586         /*
1587          * We cannot attach a context after trace has been started for a
1588          * session because the metadata does not allow expressing this
1589          * information outside of the original channel scope.
1590          */
1591         if (session->priv->been_active)
1592                 return -EPERM;
1593
1594         switch (context_param->ctx) {
1595         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1596                 return lttng_add_pthread_id_to_ctx(ctx);
1597         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1598         {
1599                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1600
1601                 perf_ctx_param = &context_param->u.perf_counter;
1602                 return lttng_add_perf_counter_to_ctx(
1603                         perf_ctx_param->type,
1604                         perf_ctx_param->config,
1605                         perf_ctx_param->name,
1606                         ctx);
1607         }
1608         case LTTNG_UST_ABI_CONTEXT_VTID:
1609                 return lttng_add_vtid_to_ctx(ctx);
1610         case LTTNG_UST_ABI_CONTEXT_VPID:
1611                 return lttng_add_vpid_to_ctx(ctx);
1612         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1613                 return lttng_add_procname_to_ctx(ctx);
1614         case LTTNG_UST_ABI_CONTEXT_IP:
1615                 return lttng_add_ip_to_ctx(ctx);
1616         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1617                 return lttng_add_cpu_id_to_ctx(ctx);
1618         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1619                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1620                         ctx);
1621         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1622                 return lttng_add_cgroup_ns_to_ctx(ctx);
1623         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1624                 return lttng_add_ipc_ns_to_ctx(ctx);
1625         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1626                 return lttng_add_mnt_ns_to_ctx(ctx);
1627         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1628                 return lttng_add_net_ns_to_ctx(ctx);
1629         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1630                 return lttng_add_pid_ns_to_ctx(ctx);
1631         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1632                 return lttng_add_time_ns_to_ctx(ctx);
1633         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1634                 return lttng_add_user_ns_to_ctx(ctx);
1635         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1636                 return lttng_add_uts_ns_to_ctx(ctx);
1637         case LTTNG_UST_ABI_CONTEXT_VUID:
1638                 return lttng_add_vuid_to_ctx(ctx);
1639         case LTTNG_UST_ABI_CONTEXT_VEUID:
1640                 return lttng_add_veuid_to_ctx(ctx);
1641         case LTTNG_UST_ABI_CONTEXT_VSUID:
1642                 return lttng_add_vsuid_to_ctx(ctx);
1643         case LTTNG_UST_ABI_CONTEXT_VGID:
1644                 return lttng_add_vgid_to_ctx(ctx);
1645         case LTTNG_UST_ABI_CONTEXT_VEGID:
1646                 return lttng_add_vegid_to_ctx(ctx);
1647         case LTTNG_UST_ABI_CONTEXT_VSGID:
1648                 return lttng_add_vsgid_to_ctx(ctx);
1649         default:
1650                 return -EINVAL;
1651         }
1652 }
1653
1654 int lttng_event_enabler_attach_context(
1655                 struct lttng_event_enabler *enabler __attribute__((unused)),
1656                 struct lttng_ust_abi_context *context_param __attribute__((unused)))
1657 {
1658         return -ENOSYS;
1659 }
1660
1661 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1662 {
1663         if (!event_enabler) {
1664                 return;
1665         }
1666         cds_list_del(&event_enabler->node);
1667
1668         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1669
1670         lttng_destroy_context(event_enabler->ctx);
1671         free(event_enabler);
1672 }
1673
1674 /*
1675  * lttng_session_sync_event_enablers should be called just before starting a
1676  * session.
1677  */
1678 static
1679 void lttng_session_sync_event_enablers(struct lttng_ust_session *session)
1680 {
1681         struct lttng_event_enabler *event_enabler;
1682         struct lttng_ust_event_recorder_private *event_recorder_priv;
1683
1684         cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
1685                 lttng_event_enabler_ref_event_recorders(event_enabler);
1686         /*
1687          * For each event, if at least one of its enablers is enabled,
1688          * and its channel and session transient states are enabled, we
1689          * enable the event, else we disable it.
1690          */
1691         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1692                 struct lttng_enabler_ref *enabler_ref;
1693                 struct lttng_ust_bytecode_runtime *runtime;
1694                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1695                 int nr_filters = 0;
1696
1697                 /* Enable events */
1698                 cds_list_for_each_entry(enabler_ref,
1699                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1700                         if (enabler_ref->ref->enabled) {
1701                                 enabled = 1;
1702                                 break;
1703                         }
1704                 }
1705                 /*
1706                  * Enabled state is based on union of enablers, with
1707                  * intesection of session and channel transient enable
1708                  * states.
1709                  */
1710                 enabled = enabled && session->priv->tstate && event_recorder_priv->pub->chan->priv->parent.tstate;
1711
1712                 CMM_STORE_SHARED(event_recorder_priv->pub->parent->enabled, enabled);
1713                 /*
1714                  * Sync tracepoint registration with event enabled
1715                  * state.
1716                  */
1717                 if (enabled) {
1718                         if (!event_recorder_priv->parent.registered)
1719                                 register_event(event_recorder_priv->parent.pub);
1720                 } else {
1721                         if (event_recorder_priv->parent.registered)
1722                                 unregister_event(event_recorder_priv->parent.pub);
1723                 }
1724
1725                 /* Check if has enablers without bytecode enabled */
1726                 cds_list_for_each_entry(enabler_ref,
1727                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1728                         if (enabler_ref->ref->enabled
1729                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1730                                 has_enablers_without_filter_bytecode = 1;
1731                                 break;
1732                         }
1733                 }
1734                 event_recorder_priv->parent.has_enablers_without_filter_bytecode =
1735                         has_enablers_without_filter_bytecode;
1736
1737                 /* Enable filters */
1738                 cds_list_for_each_entry(runtime,
1739                                 &event_recorder_priv->parent.filter_bytecode_runtime_head, node) {
1740                         lttng_bytecode_sync_state(runtime);
1741                         nr_filters++;
1742                 }
1743                 CMM_STORE_SHARED(event_recorder_priv->parent.pub->eval_filter,
1744                         !(has_enablers_without_filter_bytecode || !nr_filters));
1745         }
1746         lttng_ust_tp_probe_prune_release_queue();
1747 }
1748
1749 /* Support for event notifier is introduced by probe provider major version 2. */
1750 static
1751 bool lttng_ust_probe_supports_event_notifier(const struct lttng_ust_probe_desc *probe_desc)
1752 {
1753         return probe_desc->major >= 2;
1754 }
1755
1756 static
1757 void lttng_create_event_notifier_if_missing(
1758                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1759 {
1760         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1761         struct lttng_ust_registered_probe *reg_probe;
1762         struct cds_list_head *probe_list;
1763         int i;
1764
1765         probe_list = lttng_get_probe_list_head();
1766
1767         cds_list_for_each_entry(reg_probe, probe_list, head) {
1768                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1769
1770                 for (i = 0; i < probe_desc->nr_events; i++) {
1771                         int ret;
1772                         bool found = false;
1773                         const struct lttng_ust_event_desc *desc;
1774                         struct lttng_ust_event_notifier_private *event_notifier_priv;
1775                         struct cds_hlist_head *head;
1776                         struct cds_hlist_node *node;
1777
1778                         desc = probe_desc->event_desc[i];
1779
1780                         if (!lttng_desc_match_enabler(desc,
1781                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1782                                 continue;
1783
1784                         /*
1785                          * Given the current event_notifier group, get the bucket that
1786                          * the target event_notifier would be if it was already
1787                          * created.
1788                          */
1789                         head = borrow_hash_table_bucket(
1790                                 event_notifier_group->event_notifiers_ht.table,
1791                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1792
1793                         cds_hlist_for_each_entry(event_notifier_priv, node, head, hlist) {
1794                                 /*
1795                                  * Check if event_notifier already exists by checking
1796                                  * if the event_notifier and enabler share the same
1797                                  * description and id.
1798                                  */
1799                                 if (event_notifier_priv->parent.desc == desc &&
1800                                                 event_notifier_priv->parent.user_token == event_notifier_enabler->user_token) {
1801                                         found = true;
1802                                         break;
1803                                 }
1804                         }
1805
1806                         if (found)
1807                                 continue;
1808
1809                         /* Check that the probe supports event notifiers, else report the error. */
1810                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1811                                 ERR("Probe \"%s\" contains event \"%s:%s\" which matches an enabled event notifier, "
1812                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1813                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1814                                         "this event will not generate any notification.",
1815                                         probe_desc->provider_name,
1816                                         probe_desc->provider_name, desc->event_name,
1817                                         probe_desc->major,
1818                                         probe_desc->minor);
1819                                 continue;
1820                         }
1821                         /*
1822                          * We need to create a event_notifier for this event probe.
1823                          */
1824                         ret = lttng_event_notifier_create(desc,
1825                                 event_notifier_enabler->user_token,
1826                                 event_notifier_enabler->error_counter_index,
1827                                 event_notifier_group);
1828                         if (ret) {
1829                                 DBG("Unable to create event_notifier \"%s:%s\", error %d\n",
1830                                         probe_desc->provider_name,
1831                                         probe_desc->event_desc[i]->event_name, ret);
1832                         }
1833                 }
1834         }
1835 }
1836
1837 /*
1838  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1839  */
1840 static
1841 int lttng_event_notifier_enabler_ref_event_notifiers(
1842                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1843 {
1844         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1845         struct lttng_ust_event_notifier_private *event_notifier_priv;
1846
1847          /*
1848           * Only try to create event_notifiers for enablers that are enabled, the user
1849           * might still be attaching filter or exclusion to the
1850           * event_notifier_enabler.
1851           */
1852         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1853                 goto end;
1854
1855         /* First, ensure that probe event_notifiers are created for this enabler. */
1856         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1857
1858         /* Link the created event_notifier with its associated enabler. */
1859         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1860                 struct lttng_enabler_ref *enabler_ref;
1861
1862                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier_priv->pub))
1863                         continue;
1864
1865                 enabler_ref = lttng_enabler_ref(&event_notifier_priv->parent.enablers_ref_head,
1866                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1867                 if (!enabler_ref) {
1868                         /*
1869                          * If no backward ref, create it.
1870                          * Add backward ref from event_notifier to enabler.
1871                          */
1872                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1873                         if (!enabler_ref)
1874                                 return -ENOMEM;
1875
1876                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1877                                 event_notifier_enabler);
1878                         cds_list_add(&enabler_ref->node,
1879                                 &event_notifier_priv->parent.enablers_ref_head);
1880                 }
1881
1882                 /*
1883                  * Link filter bytecodes if not linked yet.
1884                  */
1885                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1886                         &event_notifier_group->ctx,
1887                         &event_notifier_priv->parent.filter_bytecode_runtime_head,
1888                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1889
1890                 /*
1891                  * Link capture bytecodes if not linked yet.
1892                  */
1893                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1894                         &event_notifier_group->ctx, &event_notifier_priv->capture_bytecode_runtime_head,
1895                         &event_notifier_enabler->capture_bytecode_head);
1896
1897                 event_notifier_priv->num_captures = event_notifier_enabler->num_captures;
1898         }
1899 end:
1900         return 0;
1901 }
1902
1903 static
1904 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1905 {
1906         struct lttng_event_notifier_enabler *event_notifier_enabler;
1907         struct lttng_ust_event_notifier_private *event_notifier_priv;
1908
1909         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1910                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1911
1912         /*
1913          * For each event_notifier, if at least one of its enablers is enabled,
1914          * we enable the event_notifier, else we disable it.
1915          */
1916         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1917                 struct lttng_enabler_ref *enabler_ref;
1918                 struct lttng_ust_bytecode_runtime *runtime;
1919                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1920                 int nr_filters = 0, nr_captures = 0;
1921
1922                 /* Enable event_notifiers */
1923                 cds_list_for_each_entry(enabler_ref,
1924                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1925                         if (enabler_ref->ref->enabled) {
1926                                 enabled = 1;
1927                                 break;
1928                         }
1929                 }
1930
1931                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1932                 /*
1933                  * Sync tracepoint registration with event_notifier enabled
1934                  * state.
1935                  */
1936                 if (enabled) {
1937                         if (!event_notifier_priv->parent.registered)
1938                                 register_event(event_notifier_priv->parent.pub);
1939                 } else {
1940                         if (event_notifier_priv->parent.registered)
1941                                 unregister_event(event_notifier_priv->parent.pub);
1942                 }
1943
1944                 /* Check if has enablers without bytecode enabled */
1945                 cds_list_for_each_entry(enabler_ref,
1946                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1947                         if (enabler_ref->ref->enabled
1948                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1949                                 has_enablers_without_filter_bytecode = 1;
1950                                 break;
1951                         }
1952                 }
1953                 event_notifier_priv->parent.has_enablers_without_filter_bytecode =
1954                         has_enablers_without_filter_bytecode;
1955
1956                 /* Enable filters */
1957                 cds_list_for_each_entry(runtime,
1958                                 &event_notifier_priv->parent.filter_bytecode_runtime_head, node) {
1959                         lttng_bytecode_sync_state(runtime);
1960                         nr_filters++;
1961                 }
1962                 CMM_STORE_SHARED(event_notifier_priv->parent.pub->eval_filter,
1963                         !(has_enablers_without_filter_bytecode || !nr_filters));
1964
1965                 /* Enable captures. */
1966                 cds_list_for_each_entry(runtime,
1967                                 &event_notifier_priv->capture_bytecode_runtime_head, node) {
1968                         lttng_bytecode_sync_state(runtime);
1969                         nr_captures++;
1970                 }
1971                 CMM_STORE_SHARED(event_notifier_priv->pub->eval_capture,
1972                                 !!nr_captures);
1973         }
1974         lttng_ust_tp_probe_prune_release_queue();
1975 }
1976
1977 /*
1978  * Apply enablers to session events, adding events to session if need
1979  * be. It is required after each modification applied to an active
1980  * session, and right before session "start".
1981  * "lazy" sync means we only sync if required.
1982  */
1983 static
1984 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session)
1985 {
1986         /* We can skip if session is not active */
1987         if (!session->active)
1988                 return;
1989         lttng_session_sync_event_enablers(session);
1990 }
1991
1992 /*
1993  * Update all sessions with the given app context.
1994  * Called with ust lock held.
1995  * This is invoked when an application context gets loaded/unloaded. It
1996  * ensures the context callbacks are in sync with the application
1997  * context (either app context callbacks, or dummy callbacks).
1998  */
1999 void lttng_ust_context_set_session_provider(const char *name,
2000                 size_t (*get_size)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2001                         size_t offset),
2002                 void (*record)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2003                         struct lttng_ust_ring_buffer_ctx *ctx,
2004                         struct lttng_ust_channel_buffer *chan),
2005                 void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2006                         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, struct lttng_ust_probe_ctx *probe_ctx,
2044                         size_t offset),
2045                 void (*record)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2046                         struct lttng_ust_ring_buffer_ctx *ctx,
2047                         struct lttng_ust_channel_buffer *chan),
2048                 void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx,
2049                         struct lttng_ust_ctx_value *value),
2050                 void *priv)
2051 {
2052         struct lttng_event_notifier_group *event_notifier_group;
2053
2054         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2055                 int ret;
2056
2057                 ret = lttng_ust_context_set_provider_rcu(
2058                                 &event_notifier_group->ctx,
2059                                 name, get_size, record, get_value, priv);
2060                 if (ret)
2061                         abort();
2062         }
2063 }
2064
2065 int lttng_ust_session_uuid_validate(struct lttng_ust_session *session,
2066                 unsigned char *uuid)
2067 {
2068         if (!session)
2069                 return 0;
2070         /* Compare UUID with session. */
2071         if (session->priv->uuid_set) {
2072                 if (memcmp(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN)) {
2073                         return -1;
2074                 }
2075         } else {
2076                 memcpy(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
2077                 session->priv->uuid_set = true;
2078         }
2079         return 0;
2080
2081 }