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