liblttng-ust/lttng-events.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Holds LTTng per-session event registry.
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <stdio.h>
  11 #include <assert.h>
  12 #include <errno.h>
  13 #include <limits.h>
  14 #include <pthread.h>
  15 #include <sys/shm.h>
  16 #include <sys/ipc.h>
  17 #include <stdint.h>
  18 #include <stddef.h>
  19 #include <inttypes.h>
  20 #include <time.h>
  21 #include <stdbool.h>
  22 #include <unistd.h>
  23 #include <dlfcn.h>
  24 #include <lttng/ust-endian.h>
  25
  26 #include <urcu/arch.h>
  27 #include <urcu/compiler.h>
  28 #include <urcu/hlist.h>
  29 #include <urcu/list.h>
  30 #include <urcu/uatomic.h>
  31
  32 #include <lttng/tracepoint.h>
  33 #include <lttng/ust-events.h>
  34
  35 #include <usterr-signal-safe.h>
  36 #include <ust-helper.h>
  37 #include <lttng/ust-ctl.h>
  38 #include <ust-comm.h>
  39 #include <ust-fd.h>
  40 #include <ust-dynamic-type.h>
  41 #include <ust-context-provider.h>
  42 #include "error.h"
  43 #include "compat.h"
  44 #include "lttng-ust-uuid.h"
  45
  46 #include "tracepoint-internal.h"
  47 #include "string-utils.h"
  48 #include "lttng-bytecode.h"
  49 #include "lttng-tracer.h"
  50 #include "lttng-tracer-core.h"
  51 #include "lttng-ust-statedump.h"
  52 #include "context-internal.h"
  53 #include "ust-events-internal.h"
  54 #include "wait.h"
  55 #include "../libringbuffer/shm.h"
  56 #include "../libcounter/counter.h"
  57 #include "jhash.h"
  58 #include <lttng/ust-abi.h>
  59
  60 /*
  61  * All operations within this file are called by the communication
  62  * thread, under ust_lock protection.
  63  */
  64
  65 static CDS_LIST_HEAD(sessions);
  66 static CDS_LIST_HEAD(event_notifier_groups);
  67
  68 struct cds_list_head *lttng_get_sessions(void)
  69 {
  70         return &sessions;
  71 }
  72
  73 static void _lttng_event_recorder_destroy(struct lttng_ust_event_recorder *event_recorder);
  74 static void _lttng_event_notifier_destroy(
  75                 struct lttng_ust_event_notifier *event_notifier);
  76 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  77
  78 static
  79 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  80 static
  81 void lttng_session_sync_event_enablers(struct lttng_session *session);
  82 static
  83 void lttng_event_notifier_group_sync_enablers(
  84                 struct lttng_event_notifier_group *event_notifier_group);
  85 static
  86 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  87
  88 /*
  89  * Called with ust lock held.
  90  */
  91 int lttng_session_active(void)
  92 {
  93         struct lttng_ust_session_private *iter;
  94
  95         cds_list_for_each_entry(iter, &sessions, node) {
  96                 if (iter->pub->active)
  97                         return 1;
  98         }
  99         return 0;
 100 }
 101
 102 static
 103 int lttng_loglevel_match(int loglevel,
 104                 unsigned int has_loglevel,
 105                 enum lttng_ust_abi_loglevel_type req_type,
 106                 int req_loglevel)
 107 {
 108         if (!has_loglevel)
 109                 loglevel = TRACE_DEFAULT;
 110         switch (req_type) {
 111         case LTTNG_UST_ABI_LOGLEVEL_RANGE:
 112                 if (loglevel <= req_loglevel
 113                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 114                         return 1;
 115                 else
 116                         return 0;
 117         case LTTNG_UST_ABI_LOGLEVEL_SINGLE:
 118                 if (loglevel == req_loglevel
 119                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 120                         return 1;
 121                 else
 122                         return 0;
 123         case LTTNG_UST_ABI_LOGLEVEL_ALL:
 124         default:
 125                 if (loglevel <= TRACE_DEBUG)
 126                         return 1;
 127                 else
 128                         return 0;
 129         }
 130 }
 131
 132 struct lttng_session *lttng_session_create(void)
 133 {
 134         struct lttng_session *session;
 135         struct lttng_ust_session_private *session_priv;
 136         int i;
 137
 138         session = zmalloc(sizeof(struct lttng_session));
 139         if (!session)
 140                 return NULL;
 141         session->struct_size = sizeof(struct lttng_session);
 142         session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
 143         if (!session_priv) {
 144                 free(session);
 145                 return NULL;
 146         }
 147         session->priv = session_priv;
 148         session_priv->pub = session;
 149         if (lttng_context_init_all(&session->priv->ctx)) {
 150                 free(session_priv);
 151                 free(session);
 152                 return NULL;
 153         }
 154         CDS_INIT_LIST_HEAD(&session->priv->chan_head);
 155         CDS_INIT_LIST_HEAD(&session->priv->events_head);
 156         CDS_INIT_LIST_HEAD(&session->priv->enums_head);
 157         CDS_INIT_LIST_HEAD(&session->priv->enablers_head);
 158         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 159                 CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 160         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 161                 CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
 162         cds_list_add(&session->priv->node, &sessions);
 163         return session;
 164 }
 165
 166 struct lttng_counter *lttng_ust_counter_create(
 167                 const char *counter_transport_name,
 168                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 169 {
 170         struct lttng_counter_transport *counter_transport = NULL;
 171         struct lttng_counter *counter = NULL;
 172
 173         counter_transport = lttng_counter_transport_find(counter_transport_name);
 174         if (!counter_transport)
 175                 goto notransport;
 176         counter = zmalloc(sizeof(struct lttng_counter));
 177         if (!counter)
 178                 goto nomem;
 179
 180         counter->ops = &counter_transport->ops;
 181         counter->transport = counter_transport;
 182
 183         counter->counter = counter->ops->counter_create(
 184                         number_dimensions, dimensions, 0,
 185                         -1, 0, NULL, false);
 186         if (!counter->counter) {
 187                 goto create_error;
 188         }
 189
 190         return counter;
 191
 192 create_error:
 193         free(counter);
 194 nomem:
 195 notransport:
 196         return NULL;
 197 }
 198
 199 static
 200 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 201 {
 202         counter->ops->counter_destroy(counter->counter);
 203         free(counter);
 204 }
 205
 206 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 207 {
 208         struct lttng_event_notifier_group *event_notifier_group;
 209         int i;
 210
 211         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 212         if (!event_notifier_group)
 213                 return NULL;
 214
 215         /* Add all contexts. */
 216         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 217                 free(event_notifier_group);
 218                 return NULL;
 219         }
 220
 221         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 222         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 223         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 224                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 225
 226         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 227
 228         return event_notifier_group;
 229 }
 230
 231 /*
 232  * Only used internally at session destruction.
 233  */
 234 static
 235 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 236 {
 237         struct channel *chan;
 238         struct lttng_ust_shm_handle *handle;
 239
 240         cds_list_del(&lttng_chan->node);
 241         lttng_destroy_context(lttng_chan->ctx);
 242         chan = lttng_chan->chan;
 243         handle = lttng_chan->handle;
 244         /*
 245          * note: lttng_chan is private data contained within handle. It
 246          * will be freed along with the handle.
 247          */
 248         channel_destroy(chan, handle, 0);
 249 }
 250
 251 static
 252 void register_event_recorder(struct lttng_ust_event_recorder *event_recorder)
 253 {
 254         int ret;
 255         const struct lttng_event_desc *desc;
 256
 257         assert(event_recorder->parent->priv->registered == 0);
 258         desc = event_recorder->parent->priv->desc;
 259         ret = __tracepoint_probe_register_queue_release(desc->name,
 260                         desc->probe_callback,
 261                         event_recorder, desc->signature);
 262         WARN_ON_ONCE(ret);
 263         if (!ret)
 264                 event_recorder->parent->priv->registered = 1;
 265 }
 266
 267 static
 268 void register_event_notifier(struct lttng_ust_event_notifier *event_notifier)
 269 {
 270         int ret;
 271         const struct lttng_event_desc *desc;
 272
 273         assert(event_notifier->parent->priv->registered == 0);
 274         desc = event_notifier->parent->priv->desc;
 275         ret = __tracepoint_probe_register_queue_release(desc->name,
 276                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 277         WARN_ON_ONCE(ret);
 278         if (!ret)
 279                 event_notifier->parent->priv->registered = 1;
 280 }
 281
 282 static
 283 void unregister_event_recorder(struct lttng_ust_event_recorder *event_recorder)
 284 {
 285         int ret;
 286         const struct lttng_event_desc *desc;
 287
 288         assert(event_recorder->parent->priv->registered == 1);
 289         desc = event_recorder->parent->priv->desc;
 290         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 291                         desc->probe_callback,
 292                         event_recorder);
 293         WARN_ON_ONCE(ret);
 294         if (!ret)
 295                 event_recorder->parent->priv->registered = 0;
 296 }
 297
 298 static
 299 void unregister_event_notifier(struct lttng_ust_event_notifier *event_notifier)
 300 {
 301         int ret;
 302         const struct lttng_event_desc *desc;
 303
 304         assert(event_notifier->parent->priv->registered == 1);
 305         desc = event_notifier->parent->priv->desc;
 306         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 307                 desc->u.ext.event_notifier_callback, event_notifier);
 308         WARN_ON_ONCE(ret);
 309         if (!ret)
 310                 event_notifier->parent->priv->registered = 0;
 311 }
 312
 313 /*
 314  * Only used internally at session destruction.
 315  */
 316 static
 317 void _lttng_event_recorder_unregister(struct lttng_ust_event_recorder *event_recorder)
 318 {
 319         if (event_recorder->parent->priv->registered)
 320                 unregister_event_recorder(event_recorder);
 321 }
 322
 323 /*
 324  * Only used internally at session destruction.
 325  */
 326 static
 327 void _lttng_event_notifier_unregister(struct lttng_ust_event_notifier *event_notifier)
 328 {
 329         if (event_notifier->parent->priv->registered)
 330                 unregister_event_notifier(event_notifier);
 331 }
 332
 333 void lttng_session_destroy(struct lttng_session *session)
 334 {
 335         struct lttng_channel *chan, *tmpchan;
 336         struct lttng_ust_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
 337         struct lttng_enum *_enum, *tmp_enum;
 338         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 339
 340         CMM_ACCESS_ONCE(session->active) = 0;
 341         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
 342                 _lttng_event_recorder_unregister(event_recorder_priv->pub);
 343         }
 344         lttng_ust_urcu_synchronize_rcu();       /* Wait for in-flight events to complete */
 345         __tracepoint_probe_prune_release_queue();
 346         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 347                         &session->priv->enablers_head, node)
 348                 lttng_event_enabler_destroy(event_enabler);
 349         cds_list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv,
 350                         &session->priv->events_head, node)
 351                 _lttng_event_recorder_destroy(event_recorder_priv->pub);
 352         cds_list_for_each_entry_safe(_enum, tmp_enum,
 353                         &session->priv->enums_head, node)
 354                 _lttng_enum_destroy(_enum);
 355         cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 356                 _lttng_channel_unmap(chan);
 357         cds_list_del(&session->priv->node);
 358         lttng_destroy_context(session->priv->ctx);
 359         free(session->priv);
 360         free(session);
 361 }
 362
 363 void lttng_event_notifier_group_destroy(
 364                 struct lttng_event_notifier_group *event_notifier_group)
 365 {
 366         int close_ret;
 367         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 368         struct lttng_ust_event_notifier_private *notifier_priv, *tmpnotifier_priv;
 369
 370         if (!event_notifier_group) {
 371                 return;
 372         }
 373
 374         cds_list_for_each_entry(notifier_priv,
 375                         &event_notifier_group->event_notifiers_head, node)
 376                 _lttng_event_notifier_unregister(notifier_priv->pub);
 377
 378         lttng_ust_urcu_synchronize_rcu();
 379
 380         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 381                         &event_notifier_group->enablers_head, node)
 382                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 383
 384         cds_list_for_each_entry_safe(notifier_priv, tmpnotifier_priv,
 385                         &event_notifier_group->event_notifiers_head, node)
 386                 _lttng_event_notifier_destroy(notifier_priv->pub);
 387
 388         if (event_notifier_group->error_counter)
 389                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 390
 391         /* Close the notification fd to the listener of event_notifiers. */
 392
 393         lttng_ust_lock_fd_tracker();
 394         close_ret = close(event_notifier_group->notification_fd);
 395         if (!close_ret) {
 396                 lttng_ust_delete_fd_from_tracker(
 397                                 event_notifier_group->notification_fd);
 398         } else {
 399                 PERROR("close");
 400                 abort();
 401         }
 402         lttng_ust_unlock_fd_tracker();
 403
 404         cds_list_del(&event_notifier_group->node);
 405
 406         free(event_notifier_group);
 407 }
 408
 409 static
 410 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 411 {
 412         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 413         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 414
 415         if (!enabler) {
 416                 return;
 417         }
 418
 419         /* Destroy filter bytecode */
 420         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 421                         &enabler->filter_bytecode_head, node) {
 422                 free(filter_node);
 423         }
 424
 425         /* Destroy excluders */
 426         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 427                         &enabler->excluder_head, node) {
 428                 free(excluder_node);
 429         }
 430 }
 431
 432  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 433 {
 434         if (!event_notifier_enabler) {
 435                 return;
 436         }
 437
 438         cds_list_del(&event_notifier_enabler->node);
 439
 440         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 441
 442         free(event_notifier_enabler);
 443 }
 444
 445 static
 446 int lttng_enum_create(const struct lttng_enum_desc *desc,
 447                 struct lttng_session *session)
 448 {
 449         const char *enum_name = desc->name;
 450         struct lttng_enum *_enum;
 451         struct cds_hlist_head *head;
 452         int ret = 0;
 453         size_t name_len = strlen(enum_name);
 454         uint32_t hash;
 455         int notify_socket;
 456
 457         /* Check if this enum is already registered for this session. */
 458         hash = jhash(enum_name, name_len, 0);
 459         head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 460
 461         _enum = lttng_ust_enum_get_from_desc(session, desc);
 462         if (_enum) {
 463                 ret = -EEXIST;
 464                 goto exist;
 465         }
 466
 467         notify_socket = lttng_get_notify_socket(session->priv->owner);
 468         if (notify_socket < 0) {
 469                 ret = notify_socket;
 470                 goto socket_error;
 471         }
 472
 473         _enum = zmalloc(sizeof(*_enum));
 474         if (!_enum) {
 475                 ret = -ENOMEM;
 476                 goto cache_error;
 477         }
 478         _enum->session = session;
 479         _enum->desc = desc;
 480
 481         ret = ustcomm_register_enum(notify_socket,
 482                 session->priv->objd,
 483                 enum_name,
 484                 desc->nr_entries,
 485                 desc->entries,
 486                 &_enum->id);
 487         if (ret < 0) {
 488                 DBG("Error (%d) registering enumeration to sessiond", ret);
 489                 goto sessiond_register_error;
 490         }
 491         cds_list_add(&_enum->node, &session->priv->enums_head);
 492         cds_hlist_add_head(&_enum->hlist, head);
 493         return 0;
 494
 495 sessiond_register_error:
 496         free(_enum);
 497 cache_error:
 498 socket_error:
 499 exist:
 500         return ret;
 501 }
 502
 503 static
 504 int lttng_create_enum_check(const struct lttng_type *type,
 505                 struct lttng_session *session)
 506 {
 507         switch (type->atype) {
 508         case atype_enum_nestable:
 509         {
 510                 const struct lttng_enum_desc *enum_desc;
 511                 int ret;
 512
 513                 enum_desc = type->u.enum_nestable.desc;
 514                 ret = lttng_enum_create(enum_desc, session);
 515                 if (ret && ret != -EEXIST) {
 516                         DBG("Unable to create enum error: (%d)", ret);
 517                         return ret;
 518                 }
 519                 break;
 520         }
 521         case atype_dynamic:
 522         {
 523                 const struct lttng_event_field *tag_field_generic;
 524                 const struct lttng_enum_desc *enum_desc;
 525                 int ret;
 526
 527                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 528                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 529                 ret = lttng_enum_create(enum_desc, session);
 530                 if (ret && ret != -EEXIST) {
 531                         DBG("Unable to create enum error: (%d)", ret);
 532                         return ret;
 533                 }
 534                 break;
 535         }
 536         default:
 537                 /* TODO: nested types when they become supported. */
 538                 break;
 539         }
 540         return 0;
 541 }
 542
 543 static
 544 int lttng_create_all_event_enums(size_t nr_fields,
 545                 const struct lttng_event_field *event_fields,
 546                 struct lttng_session *session)
 547 {
 548         size_t i;
 549         int ret;
 550
 551         /* For each field, ensure enum is part of the session. */
 552         for (i = 0; i < nr_fields; i++) {
 553                 const struct lttng_type *type = &event_fields[i].type;
 554
 555                 ret = lttng_create_enum_check(type, session);
 556                 if (ret)
 557                         return ret;
 558         }
 559         return 0;
 560 }
 561
 562 static
 563 int lttng_create_all_ctx_enums(size_t nr_fields,
 564                 const struct lttng_ctx_field *ctx_fields,
 565                 struct lttng_session *session)
 566 {
 567         size_t i;
 568         int ret;
 569
 570         /* For each field, ensure enum is part of the session. */
 571         for (i = 0; i < nr_fields; i++) {
 572                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 573
 574                 ret = lttng_create_enum_check(type, session);
 575                 if (ret)
 576                         return ret;
 577         }
 578         return 0;
 579 }
 580
 581 /*
 582  * Ensure that a state-dump will be performed for this session at the end
 583  * of the current handle_message().
 584  */
 585 int lttng_session_statedump(struct lttng_session *session)
 586 {
 587         session->priv->statedump_pending = 1;
 588         lttng_ust_sockinfo_session_enabled(session->priv->owner);
 589         return 0;
 590 }
 591
 592 int lttng_session_enable(struct lttng_session *session)
 593 {
 594         int ret = 0;
 595         struct lttng_channel *chan;
 596         int notify_socket;
 597
 598         if (session->active) {
 599                 ret = -EBUSY;
 600                 goto end;
 601         }
 602
 603         notify_socket = lttng_get_notify_socket(session->priv->owner);
 604         if (notify_socket < 0)
 605                 return notify_socket;
 606
 607         /* Set transient enabler state to "enabled" */
 608         session->priv->tstate = 1;
 609
 610         /* We need to sync enablers with session before activation. */
 611         lttng_session_sync_event_enablers(session);
 612
 613         /*
 614          * Snapshot the number of events per channel to know the type of header
 615          * we need to use.
 616          */
 617         cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 618                 const struct lttng_ctx *ctx;
 619                 const struct lttng_ctx_field *fields = NULL;
 620                 size_t nr_fields = 0;
 621                 uint32_t chan_id;
 622
 623                 /* don't change it if session stop/restart */
 624                 if (chan->header_type)
 625                         continue;
 626                 ctx = chan->ctx;
 627                 if (ctx) {
 628                         nr_fields = ctx->nr_fields;
 629                         fields = ctx->fields;
 630                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 631                                 session);
 632                         if (ret < 0) {
 633                                 DBG("Error (%d) adding enum to session", ret);
 634                                 return ret;
 635                         }
 636                 }
 637                 ret = ustcomm_register_channel(notify_socket,
 638                         session,
 639                         session->priv->objd,
 640                         chan->objd,
 641                         nr_fields,
 642                         fields,
 643                         &chan_id,
 644                         &chan->header_type);
 645                 if (ret) {
 646                         DBG("Error (%d) registering channel to sessiond", ret);
 647                         return ret;
 648                 }
 649                 if (chan_id != chan->id) {
 650                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 651                                 chan_id, chan->id);
 652                         return -EINVAL;
 653                 }
 654         }
 655
 656         /* Set atomically the state to "active" */
 657         CMM_ACCESS_ONCE(session->active) = 1;
 658         CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 659
 660         ret = lttng_session_statedump(session);
 661         if (ret)
 662                 return ret;
 663 end:
 664         return ret;
 665 }
 666
 667 int lttng_session_disable(struct lttng_session *session)
 668 {
 669         int ret = 0;
 670
 671         if (!session->active) {
 672                 ret = -EBUSY;
 673                 goto end;
 674         }
 675         /* Set atomically the state to "inactive" */
 676         CMM_ACCESS_ONCE(session->active) = 0;
 677
 678         /* Set transient enabler state to "disabled" */
 679         session->priv->tstate = 0;
 680         lttng_session_sync_event_enablers(session);
 681 end:
 682         return ret;
 683 }
 684
 685 int lttng_channel_enable(struct lttng_channel *channel)
 686 {
 687         int ret = 0;
 688
 689         if (channel->enabled) {
 690                 ret = -EBUSY;
 691                 goto end;
 692         }
 693         /* Set transient enabler state to "enabled" */
 694         channel->tstate = 1;
 695         lttng_session_sync_event_enablers(channel->session);
 696         /* Set atomically the state to "enabled" */
 697         CMM_ACCESS_ONCE(channel->enabled) = 1;
 698 end:
 699         return ret;
 700 }
 701
 702 int lttng_channel_disable(struct lttng_channel *channel)
 703 {
 704         int ret = 0;
 705
 706         if (!channel->enabled) {
 707                 ret = -EBUSY;
 708                 goto end;
 709         }
 710         /* Set atomically the state to "disabled" */
 711         CMM_ACCESS_ONCE(channel->enabled) = 0;
 712         /* Set transient enabler state to "enabled" */
 713         channel->tstate = 0;
 714         lttng_session_sync_event_enablers(channel->session);
 715 end:
 716         return ret;
 717 }
 718
 719 static inline
 720 struct cds_hlist_head *borrow_hash_table_bucket(
 721                 struct cds_hlist_head *hash_table,
 722                 unsigned int hash_table_size,
 723                 const struct lttng_event_desc *desc)
 724 {
 725         const char *event_name;
 726         size_t name_len;
 727         uint32_t hash;
 728
 729         event_name = desc->name;
 730         name_len = strlen(event_name);
 731
 732         hash = jhash(event_name, name_len, 0);
 733         return &hash_table[hash & (hash_table_size - 1)];
 734 }
 735
 736 /*
 737  * Supports event creation while tracing session is active.
 738  */
 739 static
 740 int lttng_event_recorder_create(const struct lttng_event_desc *desc,
 741                 struct lttng_channel *chan)
 742 {
 743         struct lttng_ust_event_recorder *event_recorder;
 744         struct lttng_ust_event_recorder_private *event_recorder_priv;
 745         struct lttng_session *session = chan->session;
 746         struct cds_hlist_head *head;
 747         int ret = 0;
 748         int notify_socket, loglevel;
 749         const char *uri;
 750
 751         head = borrow_hash_table_bucket(chan->session->priv->events_ht.table,
 752                 LTTNG_UST_EVENT_HT_SIZE, desc);
 753
 754         notify_socket = lttng_get_notify_socket(session->priv->owner);
 755         if (notify_socket < 0) {
 756                 ret = notify_socket;
 757                 goto socket_error;
 758         }
 759
 760         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 761                         session);
 762         if (ret < 0) {
 763                 DBG("Error (%d) adding enum to session", ret);
 764                 goto create_enum_error;
 765         }
 766
 767         /*
 768          * Check if loglevel match. Refuse to connect event if not.
 769          */
 770         event_recorder = zmalloc(sizeof(struct lttng_ust_event_recorder));
 771         if (!event_recorder) {
 772                 ret = -ENOMEM;
 773                 goto cache_error;
 774         }
 775         event_recorder->struct_size = sizeof(struct lttng_ust_event_recorder);
 776
 777         event_recorder->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 778         if (!event_recorder->parent) {
 779                 ret = -ENOMEM;
 780                 goto parent_error;
 781         }
 782         event_recorder->parent->struct_size = sizeof(struct lttng_ust_event_common);
 783         event_recorder->parent->type = LTTNG_UST_EVENT_TYPE_RECORDER;
 784
 785         event_recorder_priv = zmalloc(sizeof(struct lttng_ust_event_recorder_private));
 786         if (!event_recorder_priv) {
 787                 ret = -ENOMEM;
 788                 goto priv_error;
 789         }
 790         event_recorder->priv = event_recorder_priv;
 791         event_recorder_priv->pub = event_recorder;
 792         event_recorder->parent->priv = &event_recorder_priv->parent;
 793         event_recorder_priv->parent.pub = event_recorder->parent;
 794
 795         event_recorder->chan = chan;
 796
 797         /* Event will be enabled by enabler sync. */
 798         event_recorder->parent->enabled = 0;
 799         event_recorder->parent->priv->registered = 0;
 800         CDS_INIT_LIST_HEAD(&event_recorder->parent->filter_bytecode_runtime_head);
 801         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 802         event_recorder->parent->priv->desc = desc;
 803
 804         if (desc->loglevel)
 805                 loglevel = *(*event_recorder->parent->priv->desc->loglevel);
 806         else
 807                 loglevel = TRACE_DEFAULT;
 808         if (desc->u.ext.model_emf_uri)
 809                 uri = *(desc->u.ext.model_emf_uri);
 810         else
 811                 uri = NULL;
 812
 813         /* Fetch event ID from sessiond */
 814         ret = ustcomm_register_event(notify_socket,
 815                 session,
 816                 session->priv->objd,
 817                 chan->objd,
 818                 desc->name,
 819                 loglevel,
 820                 desc->signature,
 821                 desc->nr_fields,
 822                 desc->fields,
 823                 uri,
 824                 &event_recorder->id);
 825         if (ret < 0) {
 826                 DBG("Error (%d) registering event to sessiond", ret);
 827                 goto sessiond_register_error;
 828         }
 829
 830         cds_list_add(&event_recorder->priv->node, &chan->session->priv->events_head);
 831         cds_hlist_add_head(&event_recorder->priv->hlist, head);
 832         return 0;
 833
 834 sessiond_register_error:
 835         free(event_recorder_priv);
 836 priv_error:
 837         free(event_recorder->parent);
 838 parent_error:
 839         free(event_recorder);
 840 cache_error:
 841 create_enum_error:
 842 socket_error:
 843         return ret;
 844 }
 845
 846 static
 847 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 848                 uint64_t token, uint64_t error_counter_index,
 849                 struct lttng_event_notifier_group *event_notifier_group)
 850 {
 851         struct lttng_ust_event_notifier *event_notifier;
 852         struct lttng_ust_event_notifier_private *event_notifier_priv;
 853         struct cds_hlist_head *head;
 854         int ret = 0;
 855
 856         /*
 857          * Get the hashtable bucket the created lttng_event_notifier object
 858          * should be inserted.
 859          */
 860         head = borrow_hash_table_bucket(
 861                 event_notifier_group->event_notifiers_ht.table,
 862                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 863
 864         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 865         if (!event_notifier) {
 866                 ret = -ENOMEM;
 867                 goto error;
 868         }
 869         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 870
 871         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 872         if (!event_notifier->parent) {
 873                 ret = -ENOMEM;
 874                 goto parent_error;
 875         }
 876         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 877         event_notifier->parent->type = LTTNG_UST_EVENT_TYPE_NOTIFIER;
 878
 879         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 880         if (!event_notifier_priv) {
 881                 ret = -ENOMEM;
 882                 goto priv_error;
 883         }
 884         event_notifier->priv = event_notifier_priv;
 885         event_notifier_priv->pub = event_notifier;
 886         event_notifier->parent->priv = &event_notifier_priv->parent;
 887         event_notifier_priv->parent.pub = event_notifier->parent;
 888
 889         event_notifier_priv->group = event_notifier_group;
 890         event_notifier_priv->parent.user_token = token;
 891         event_notifier_priv->error_counter_index = error_counter_index;
 892
 893         /* Event notifier will be enabled by enabler sync. */
 894         event_notifier->parent->enabled = 0;
 895         event_notifier_priv->parent.registered = 0;
 896
 897         CDS_INIT_LIST_HEAD(&event_notifier->parent->filter_bytecode_runtime_head);
 898         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 899         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 900         event_notifier_priv->parent.desc = desc;
 901         event_notifier->notification_send = lttng_event_notifier_notification_send;
 902
 903         cds_list_add(&event_notifier_priv->node,
 904                         &event_notifier_group->event_notifiers_head);
 905         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 906
 907         return 0;
 908
 909 priv_error:
 910         free(event_notifier->parent);
 911 parent_error:
 912         free(event_notifier);
 913 error:
 914         return ret;
 915 }
 916
 917 static
 918 void _lttng_event_notifier_destroy(struct lttng_ust_event_notifier *event_notifier)
 919 {
 920         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 921
 922         /* Remove from event_notifier list. */
 923         cds_list_del(&event_notifier->priv->node);
 924         /* Remove from event_notifier hash table. */
 925         cds_hlist_del(&event_notifier->priv->hlist);
 926
 927         lttng_free_event_filter_runtime(event_notifier->parent);
 928
 929         /* Free event_notifier enabler refs */
 930         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 931                         &event_notifier->priv->parent.enablers_ref_head, node)
 932                 free(enabler_ref);
 933         free(event_notifier->priv);
 934         free(event_notifier->parent);
 935         free(event_notifier);
 936 }
 937
 938 static
 939 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 940                 struct lttng_enabler *enabler)
 941 {
 942         int loglevel = 0;
 943         unsigned int has_loglevel = 0;
 944
 945         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 946         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 947                         desc->name, SIZE_MAX))
 948                 return 0;
 949         if (desc->loglevel) {
 950                 loglevel = *(*desc->loglevel);
 951                 has_loglevel = 1;
 952         }
 953         if (!lttng_loglevel_match(loglevel,
 954                         has_loglevel,
 955                         enabler->event_param.loglevel_type,
 956                         enabler->event_param.loglevel))
 957                 return 0;
 958         return 1;
 959 }
 960
 961 static
 962 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 963                 struct lttng_enabler *enabler)
 964 {
 965         int loglevel = 0;
 966         unsigned int has_loglevel = 0;
 967
 968         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 969         if (strcmp(desc->name, enabler->event_param.name))
 970                 return 0;
 971         if (desc->loglevel) {
 972                 loglevel = *(*desc->loglevel);
 973                 has_loglevel = 1;
 974         }
 975         if (!lttng_loglevel_match(loglevel,
 976                         has_loglevel,
 977                         enabler->event_param.loglevel_type,
 978                         enabler->event_param.loglevel))
 979                 return 0;
 980         return 1;
 981 }
 982
 983 static
 984 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 985                 struct lttng_enabler *enabler)
 986 {
 987         switch (enabler->format_type) {
 988         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 989         {
 990                 struct lttng_ust_excluder_node *excluder;
 991
 992                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 993                         return 0;
 994                 }
 995
 996                 /*
 997                  * If the matching event matches with an excluder,
 998                  * return 'does not match'
 999                  */
1000                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
1001                         int count;
1002
1003                         for (count = 0; count < excluder->excluder.count; count++) {
1004                                 int len;
1005                                 char *excluder_name;
1006
1007                                 excluder_name = (char *) (excluder->excluder.names)
1008                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
1009                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
1010                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
1011                                         return 0;
1012                         }
1013                 }
1014                 return 1;
1015         }
1016         case LTTNG_ENABLER_FORMAT_EVENT:
1017                 return lttng_desc_match_event_enabler(desc, enabler);
1018         default:
1019                 return -EINVAL;
1020         }
1021 }
1022
1023 static
1024 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
1025                 struct lttng_ust_event_recorder *event_recorder)
1026 {
1027         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
1028                         lttng_event_enabler_as_enabler(event_enabler))
1029                         && event_recorder->chan == event_enabler->chan)
1030                 return 1;
1031         else
1032                 return 0;
1033 }
1034
1035 static
1036 int lttng_event_notifier_enabler_match_event_notifier(
1037                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1038                 struct lttng_ust_event_notifier *event_notifier)
1039 {
1040         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
1041                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1042
1043         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
1044                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
1045                 return 1;
1046         else
1047                 return 0;
1048 }
1049
1050 static
1051 struct lttng_enabler_ref *lttng_enabler_ref(
1052                 struct cds_list_head *enabler_ref_list,
1053                 struct lttng_enabler *enabler)
1054 {
1055         struct lttng_enabler_ref *enabler_ref;
1056
1057         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1058                 if (enabler_ref->ref == enabler)
1059                         return enabler_ref;
1060         }
1061         return NULL;
1062 }
1063
1064 /*
1065  * Create struct lttng_event if it is missing and present in the list of
1066  * tracepoint probes.
1067  */
1068 static
1069 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1070 {
1071         struct lttng_session *session = event_enabler->chan->session;
1072         struct lttng_probe_desc *probe_desc;
1073         const struct lttng_event_desc *desc;
1074         struct lttng_ust_event_recorder_private *event_recorder_priv;
1075         int i;
1076         struct cds_list_head *probe_list;
1077
1078         probe_list = lttng_get_probe_list_head();
1079         /*
1080          * For each probe event, if we find that a probe event matches
1081          * our enabler, create an associated lttng_event if not
1082          * already present.
1083          */
1084         cds_list_for_each_entry(probe_desc, probe_list, head) {
1085                 for (i = 0; i < probe_desc->nr_events; i++) {
1086                         int ret;
1087                         bool found = false;
1088                         struct cds_hlist_head *head;
1089                         struct cds_hlist_node *node;
1090
1091                         desc = probe_desc->event_desc[i];
1092                         if (!lttng_desc_match_enabler(desc,
1093                                         lttng_event_enabler_as_enabler(event_enabler)))
1094                                 continue;
1095
1096                         head = borrow_hash_table_bucket(
1097                                 session->priv->events_ht.table,
1098                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1099
1100                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1101                                 if (event_recorder_priv->parent.desc == desc
1102                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1103                                         found = true;
1104                                         break;
1105                                 }
1106                         }
1107                         if (found)
1108                                 continue;
1109
1110                         /*
1111                          * We need to create an event for this
1112                          * event probe.
1113                          */
1114                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1115                                         event_enabler->chan);
1116                         if (ret) {
1117                                 DBG("Unable to create event %s, error %d\n",
1118                                         probe_desc->event_desc[i]->name, ret);
1119                         }
1120                 }
1121         }
1122 }
1123
1124 static
1125 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1126                 void (*event_func)(struct lttng_session *session,
1127                         struct lttng_ust_event_recorder *event_recorder),
1128                 void (*event_notifier_func)(struct lttng_ust_event_notifier *event_notifier))
1129 {
1130         struct cds_hlist_node *node, *tmp_node;
1131         struct cds_list_head *sessionsp;
1132         unsigned int i;
1133
1134         /* Get handle on list of sessions. */
1135         sessionsp = lttng_get_sessions();
1136
1137         /*
1138          * Iterate over all events in the probe provider descriptions and
1139          * sessions to queue the unregistration of the events.
1140          */
1141         for (i = 0; i < provider_desc->nr_events; i++) {
1142                 const struct lttng_event_desc *event_desc;
1143                 struct lttng_event_notifier_group *event_notifier_group;
1144                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1145                 struct lttng_ust_session_private *session_priv;
1146                 struct cds_hlist_head *head;
1147                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1148
1149                 event_desc = provider_desc->event_desc[i];
1150
1151                 /*
1152                  * Iterate over all session to find the current event
1153                  * description.
1154                  */
1155                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1156                         /*
1157                          * Get the list of events in the hashtable bucket and
1158                          * iterate to find the event matching this descriptor.
1159                          */
1160                         head = borrow_hash_table_bucket(
1161                                 session_priv->events_ht.table,
1162                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1163
1164                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1165                                 if (event_desc == event_recorder_priv->parent.desc) {
1166                                         event_func(session_priv->pub, event_recorder_priv->pub);
1167                                         break;
1168                                 }
1169                         }
1170                 }
1171
1172                 /*
1173                  * Iterate over all event_notifier groups to find the current event
1174                  * description.
1175                  */
1176                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1177                         /*
1178                          * Get the list of event_notifiers in the hashtable bucket and
1179                          * iterate to find the event_notifier matching this
1180                          * descriptor.
1181                          */
1182                         head = borrow_hash_table_bucket(
1183                                 event_notifier_group->event_notifiers_ht.table,
1184                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1185
1186                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1187                                 if (event_desc == event_notifier_priv->parent.desc) {
1188                                         event_notifier_func(event_notifier_priv->pub);
1189                                         break;
1190                                 }
1191                         }
1192                 }
1193         }
1194 }
1195
1196 static
1197 void _unregister_event_recorder(struct lttng_session *session,
1198                 struct lttng_ust_event_recorder *event_recorder)
1199 {
1200         _lttng_event_recorder_unregister(event_recorder);
1201 }
1202
1203 static
1204 void _event_enum_destroy(struct lttng_session *session,
1205                 struct lttng_ust_event_recorder *event_recorder)
1206 {
1207         unsigned int i;
1208
1209         /* Destroy enums of the current event. */
1210         for (i = 0; i < event_recorder->parent->priv->desc->nr_fields; i++) {
1211                 const struct lttng_enum_desc *enum_desc;
1212                 const struct lttng_event_field *field;
1213                 struct lttng_enum *curr_enum;
1214
1215                 field = &(event_recorder->parent->priv->desc->fields[i]);
1216                 switch (field->type.atype) {
1217                 case atype_enum_nestable:
1218                         enum_desc = field->type.u.enum_nestable.desc;
1219                         break;
1220                 default:
1221                         continue;
1222                 }
1223
1224                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1225                 if (curr_enum) {
1226                         _lttng_enum_destroy(curr_enum);
1227                 }
1228         }
1229
1230         /* Destroy event. */
1231         _lttng_event_recorder_destroy(event_recorder);
1232 }
1233
1234 /*
1235  * Iterate over all the UST sessions to unregister and destroy all probes from
1236  * the probe provider descriptor received as argument. Must me called with the
1237  * ust_lock held.
1238  */
1239 void lttng_probe_provider_unregister_events(
1240                 struct lttng_probe_desc *provider_desc)
1241 {
1242         /*
1243          * Iterate over all events in the probe provider descriptions and sessions
1244          * to queue the unregistration of the events.
1245          */
1246         probe_provider_event_for_each(provider_desc, _unregister_event_recorder,
1247                 _lttng_event_notifier_unregister);
1248
1249         /* Wait for grace period. */
1250         lttng_ust_urcu_synchronize_rcu();
1251         /* Prune the unregistration queue. */
1252         __tracepoint_probe_prune_release_queue();
1253
1254         /*
1255          * It is now safe to destroy the events and remove them from the event list
1256          * and hashtables.
1257          */
1258         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1259                 _lttng_event_notifier_destroy);
1260 }
1261
1262 /*
1263  * Create events associated with an event enabler (if not already present),
1264  * and add backward reference from the event to the enabler.
1265  */
1266 static
1267 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1268 {
1269         struct lttng_session *session = event_enabler->chan->session;
1270         struct lttng_ust_event_recorder_private *event_recorder_priv;
1271
1272         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1273                 goto end;
1274
1275         /* First ensure that probe events are created for this enabler. */
1276         lttng_create_event_if_missing(event_enabler);
1277
1278         /* For each event matching enabler in session event list. */
1279         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1280                 struct lttng_enabler_ref *enabler_ref;
1281
1282                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1283                         continue;
1284
1285                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1286                         lttng_event_enabler_as_enabler(event_enabler));
1287                 if (!enabler_ref) {
1288                         /*
1289                          * If no backward ref, create it.
1290                          * Add backward ref from event to enabler.
1291                          */
1292                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1293                         if (!enabler_ref)
1294                                 return -ENOMEM;
1295                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1296                                 event_enabler);
1297                         cds_list_add(&enabler_ref->node,
1298                                 &event_recorder_priv->parent.enablers_ref_head);
1299                 }
1300
1301                 /*
1302                  * Link filter bytecodes if not linked yet.
1303                  */
1304                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1305                         &session->priv->ctx,
1306                         &event_recorder_priv->pub->parent->filter_bytecode_runtime_head,
1307                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1308
1309                 /* TODO: merge event context. */
1310         }
1311 end:
1312         return 0;
1313 }
1314
1315 /*
1316  * Called at library load: connect the probe on all enablers matching
1317  * this event.
1318  * Called with session mutex held.
1319  */
1320 int lttng_fix_pending_events(void)
1321 {
1322         struct lttng_ust_session_private *session_priv;
1323
1324         cds_list_for_each_entry(session_priv, &sessions, node) {
1325                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1326         }
1327         return 0;
1328 }
1329
1330 int lttng_fix_pending_event_notifiers(void)
1331 {
1332         struct lttng_event_notifier_group *event_notifier_group;
1333
1334         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1335                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1336         }
1337         return 0;
1338 }
1339
1340 /*
1341  * For each session of the owner thread, execute pending statedump.
1342  * Only dump state for the sessions owned by the caller thread, because
1343  * we don't keep ust_lock across the entire iteration.
1344  */
1345 void lttng_handle_pending_statedump(void *owner)
1346 {
1347         struct lttng_ust_session_private *session_priv;
1348
1349         /* Execute state dump */
1350         do_lttng_ust_statedump(owner);
1351
1352         /* Clear pending state dump */
1353         if (ust_lock()) {
1354                 goto end;
1355         }
1356         cds_list_for_each_entry(session_priv, &sessions, node) {
1357                 if (session_priv->owner != owner)
1358                         continue;
1359                 if (!session_priv->statedump_pending)
1360                         continue;
1361                 session_priv->statedump_pending = 0;
1362         }
1363 end:
1364         ust_unlock();
1365         return;
1366 }
1367
1368 /*
1369  * Only used internally at session destruction.
1370  */
1371 static
1372 void _lttng_event_recorder_destroy(struct lttng_ust_event_recorder *event_recorder)
1373 {
1374         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1375
1376         /* Remove from event list. */
1377         cds_list_del(&event_recorder->priv->node);
1378         /* Remove from event hash table. */
1379         cds_hlist_del(&event_recorder->priv->hlist);
1380
1381         lttng_destroy_context(event_recorder->ctx);
1382         lttng_free_event_filter_runtime(event_recorder->parent);
1383         /* Free event enabler refs */
1384         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1385                         &event_recorder->parent->priv->enablers_ref_head, node)
1386                 free(enabler_ref);
1387         free(event_recorder->priv);
1388         free(event_recorder->parent);
1389         free(event_recorder);
1390 }
1391
1392 static
1393 void _lttng_enum_destroy(struct lttng_enum *_enum)
1394 {
1395         cds_list_del(&_enum->node);
1396         cds_hlist_del(&_enum->hlist);
1397         free(_enum);
1398 }
1399
1400 void lttng_ust_abi_events_exit(void)
1401 {
1402         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1403
1404         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1405                 lttng_session_destroy(session_priv->pub);
1406 }
1407
1408 /*
1409  * Enabler management.
1410  */
1411 struct lttng_event_enabler *lttng_event_enabler_create(
1412                 enum lttng_enabler_format_type format_type,
1413                 struct lttng_ust_abi_event *event_param,
1414                 struct lttng_channel *chan)
1415 {
1416         struct lttng_event_enabler *event_enabler;
1417
1418         event_enabler = zmalloc(sizeof(*event_enabler));
1419         if (!event_enabler)
1420                 return NULL;
1421         event_enabler->base.format_type = format_type;
1422         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1423         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1424         memcpy(&event_enabler->base.event_param, event_param,
1425                 sizeof(event_enabler->base.event_param));
1426         event_enabler->chan = chan;
1427         /* ctx left NULL */
1428         event_enabler->base.enabled = 0;
1429         cds_list_add(&event_enabler->node, &event_enabler->chan->session->priv->enablers_head);
1430         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1431
1432         return event_enabler;
1433 }
1434
1435 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1436                 struct lttng_event_notifier_group *event_notifier_group,
1437                 enum lttng_enabler_format_type format_type,
1438                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1439 {
1440         struct lttng_event_notifier_enabler *event_notifier_enabler;
1441
1442         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1443         if (!event_notifier_enabler)
1444                 return NULL;
1445         event_notifier_enabler->base.format_type = format_type;
1446         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1447         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1448         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1449
1450         event_notifier_enabler->user_token = event_notifier_param->event.token;
1451         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1452         event_notifier_enabler->num_captures = 0;
1453
1454         memcpy(&event_notifier_enabler->base.event_param.name,
1455                 event_notifier_param->event.name,
1456                 sizeof(event_notifier_enabler->base.event_param.name));
1457         event_notifier_enabler->base.event_param.instrumentation =
1458                 event_notifier_param->event.instrumentation;
1459         event_notifier_enabler->base.event_param.loglevel =
1460                 event_notifier_param->event.loglevel;
1461         event_notifier_enabler->base.event_param.loglevel_type =
1462                 event_notifier_param->event.loglevel_type;
1463
1464         event_notifier_enabler->base.enabled = 0;
1465         event_notifier_enabler->group = event_notifier_group;
1466
1467         cds_list_add(&event_notifier_enabler->node,
1468                         &event_notifier_group->enablers_head);
1469
1470         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1471
1472         return event_notifier_enabler;
1473 }
1474
1475 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1476 {
1477         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1478         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1479
1480         return 0;
1481 }
1482
1483 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1484 {
1485         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1486         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1487
1488         return 0;
1489 }
1490
1491 static
1492 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1493                 struct lttng_ust_bytecode_node **bytecode)
1494 {
1495         (*bytecode)->enabler = enabler;
1496         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1497         /* Take ownership of bytecode */
1498         *bytecode = NULL;
1499 }
1500
1501 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1502                 struct lttng_ust_bytecode_node **bytecode)
1503 {
1504         _lttng_enabler_attach_filter_bytecode(
1505                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1506
1507         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1508         return 0;
1509 }
1510
1511 static
1512 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1513                 struct lttng_ust_excluder_node **excluder)
1514 {
1515         (*excluder)->enabler = enabler;
1516         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1517         /* Take ownership of excluder */
1518         *excluder = NULL;
1519 }
1520
1521 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1522                 struct lttng_ust_excluder_node **excluder)
1523 {
1524         _lttng_enabler_attach_exclusion(
1525                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1526
1527         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1528         return 0;
1529 }
1530
1531 int lttng_event_notifier_enabler_enable(
1532                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1533 {
1534         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1535         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1536
1537         return 0;
1538 }
1539
1540 int lttng_event_notifier_enabler_disable(
1541                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1542 {
1543         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1544         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1545
1546         return 0;
1547 }
1548
1549 int lttng_event_notifier_enabler_attach_filter_bytecode(
1550                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1551                 struct lttng_ust_bytecode_node **bytecode)
1552 {
1553         _lttng_enabler_attach_filter_bytecode(
1554                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1555                 bytecode);
1556
1557         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1558         return 0;
1559 }
1560
1561 int lttng_event_notifier_enabler_attach_capture_bytecode(
1562                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1563                 struct lttng_ust_bytecode_node **bytecode)
1564 {
1565         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1566                         event_notifier_enabler);
1567         cds_list_add_tail(&(*bytecode)->node,
1568                         &event_notifier_enabler->capture_bytecode_head);
1569         /* Take ownership of bytecode */
1570         *bytecode = NULL;
1571         event_notifier_enabler->num_captures++;
1572
1573         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1574         return 0;
1575 }
1576
1577 int lttng_event_notifier_enabler_attach_exclusion(
1578                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1579                 struct lttng_ust_excluder_node **excluder)
1580 {
1581         _lttng_enabler_attach_exclusion(
1582                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1583                 excluder);
1584
1585         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1586         return 0;
1587 }
1588
1589 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1590                 union lttng_ust_abi_args *uargs,
1591                 struct lttng_ctx **ctx, struct lttng_session *session)
1592 {
1593         /*
1594          * We cannot attach a context after trace has been started for a
1595          * session because the metadata does not allow expressing this
1596          * information outside of the original channel scope.
1597          */
1598         if (session->priv->been_active)
1599                 return -EPERM;
1600
1601         switch (context_param->ctx) {
1602         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1603                 return lttng_add_pthread_id_to_ctx(ctx);
1604         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1605         {
1606                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1607
1608                 perf_ctx_param = &context_param->u.perf_counter;
1609                 return lttng_add_perf_counter_to_ctx(
1610                         perf_ctx_param->type,
1611                         perf_ctx_param->config,
1612                         perf_ctx_param->name,
1613                         ctx);
1614         }
1615         case LTTNG_UST_ABI_CONTEXT_VTID:
1616                 return lttng_add_vtid_to_ctx(ctx);
1617         case LTTNG_UST_ABI_CONTEXT_VPID:
1618                 return lttng_add_vpid_to_ctx(ctx);
1619         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1620                 return lttng_add_procname_to_ctx(ctx);
1621         case LTTNG_UST_ABI_CONTEXT_IP:
1622                 return lttng_add_ip_to_ctx(ctx);
1623         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1624                 return lttng_add_cpu_id_to_ctx(ctx);
1625         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1626                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1627                         ctx);
1628         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1629                 return lttng_add_cgroup_ns_to_ctx(ctx);
1630         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1631                 return lttng_add_ipc_ns_to_ctx(ctx);
1632         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1633                 return lttng_add_mnt_ns_to_ctx(ctx);
1634         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1635                 return lttng_add_net_ns_to_ctx(ctx);
1636         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1637                 return lttng_add_pid_ns_to_ctx(ctx);
1638         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1639                 return lttng_add_time_ns_to_ctx(ctx);
1640         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1641                 return lttng_add_user_ns_to_ctx(ctx);
1642         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1643                 return lttng_add_uts_ns_to_ctx(ctx);
1644         case LTTNG_UST_ABI_CONTEXT_VUID:
1645                 return lttng_add_vuid_to_ctx(ctx);
1646         case LTTNG_UST_ABI_CONTEXT_VEUID:
1647                 return lttng_add_veuid_to_ctx(ctx);
1648         case LTTNG_UST_ABI_CONTEXT_VSUID:
1649                 return lttng_add_vsuid_to_ctx(ctx);
1650         case LTTNG_UST_ABI_CONTEXT_VGID:
1651                 return lttng_add_vgid_to_ctx(ctx);
1652         case LTTNG_UST_ABI_CONTEXT_VEGID:
1653                 return lttng_add_vegid_to_ctx(ctx);
1654         case LTTNG_UST_ABI_CONTEXT_VSGID:
1655                 return lttng_add_vsgid_to_ctx(ctx);
1656         default:
1657                 return -EINVAL;
1658         }
1659 }
1660
1661 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1662                 struct lttng_ust_abi_context *context_param)
1663 {
1664         return -ENOSYS;
1665 }
1666
1667 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1668 {
1669         if (!event_enabler) {
1670                 return;
1671         }
1672         cds_list_del(&event_enabler->node);
1673
1674         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1675
1676         lttng_destroy_context(event_enabler->ctx);
1677         free(event_enabler);
1678 }
1679
1680 /*
1681  * lttng_session_sync_event_enablers should be called just before starting a
1682  * session.
1683  */
1684 static
1685 void lttng_session_sync_event_enablers(struct lttng_session *session)
1686 {
1687         struct lttng_event_enabler *event_enabler;
1688         struct lttng_ust_event_recorder_private *event_recorder_priv;
1689
1690         cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
1691                 lttng_event_enabler_ref_events(event_enabler);
1692         /*
1693          * For each event, if at least one of its enablers is enabled,
1694          * and its channel and session transient states are enabled, we
1695          * enable the event, else we disable it.
1696          */
1697         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1698                 struct lttng_enabler_ref *enabler_ref;
1699                 struct lttng_bytecode_runtime *runtime;
1700                 int enabled = 0, has_enablers_without_bytecode = 0;
1701
1702                 /* Enable events */
1703                 cds_list_for_each_entry(enabler_ref,
1704                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1705                         if (enabler_ref->ref->enabled) {
1706                                 enabled = 1;
1707                                 break;
1708                         }
1709                 }
1710                 /*
1711                  * Enabled state is based on union of enablers, with
1712                  * intesection of session and channel transient enable
1713                  * states.
1714                  */
1715                 enabled = enabled && session->priv->tstate && event_recorder_priv->pub->chan->tstate;
1716
1717                 CMM_STORE_SHARED(event_recorder_priv->pub->parent->enabled, enabled);
1718                 /*
1719                  * Sync tracepoint registration with event enabled
1720                  * state.
1721                  */
1722                 if (enabled) {
1723                         if (!event_recorder_priv->parent.registered)
1724                                 register_event_recorder(event_recorder_priv->pub);
1725                 } else {
1726                         if (event_recorder_priv->parent.registered)
1727                                 unregister_event_recorder(event_recorder_priv->pub);
1728                 }
1729
1730                 /* Check if has enablers without bytecode enabled */
1731                 cds_list_for_each_entry(enabler_ref,
1732                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1733                         if (enabler_ref->ref->enabled
1734                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1735                                 has_enablers_without_bytecode = 1;
1736                                 break;
1737                         }
1738                 }
1739                 event_recorder_priv->pub->parent->has_enablers_without_bytecode =
1740                         has_enablers_without_bytecode;
1741
1742                 /* Enable filters */
1743                 cds_list_for_each_entry(runtime,
1744                                 &event_recorder_priv->pub->parent->filter_bytecode_runtime_head, node) {
1745                         lttng_bytecode_filter_sync_state(runtime);
1746                 }
1747         }
1748         __tracepoint_probe_prune_release_queue();
1749 }
1750
1751 /* Support for event notifier is introduced by probe provider major version 2. */
1752 static
1753 bool lttng_ust_probe_supports_event_notifier(struct lttng_probe_desc *probe_desc)
1754 {
1755         return probe_desc->major >= 2;
1756 }
1757
1758 static
1759 void lttng_create_event_notifier_if_missing(
1760                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1761 {
1762         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1763         struct lttng_probe_desc *probe_desc;
1764         struct cds_list_head *probe_list;
1765         int i;
1766
1767         probe_list = lttng_get_probe_list_head();
1768
1769         cds_list_for_each_entry(probe_desc, probe_list, head) {
1770                 for (i = 0; i < probe_desc->nr_events; i++) {
1771                         int ret;
1772                         bool found = false;
1773                         const struct lttng_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\" 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,
1816                                         desc->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, error %d\n",
1830                                         probe_desc->event_desc[i]->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->pub->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->pub->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_bytecode_runtime *runtime;
1918                 int enabled = 0, has_enablers_without_bytecode = 0;
1919
1920                 /* Enable event_notifiers */
1921                 cds_list_for_each_entry(enabler_ref,
1922                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1923                         if (enabler_ref->ref->enabled) {
1924                                 enabled = 1;
1925                                 break;
1926                         }
1927                 }
1928
1929                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1930                 /*
1931                  * Sync tracepoint registration with event_notifier enabled
1932                  * state.
1933                  */
1934                 if (enabled) {
1935                         if (!event_notifier_priv->parent.registered)
1936                                 register_event_notifier(event_notifier_priv->pub);
1937                 } else {
1938                         if (event_notifier_priv->parent.registered)
1939                                 unregister_event_notifier(event_notifier_priv->pub);
1940                 }
1941
1942                 /* Check if has enablers without bytecode enabled */
1943                 cds_list_for_each_entry(enabler_ref,
1944                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1945                         if (enabler_ref->ref->enabled
1946                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1947                                 has_enablers_without_bytecode = 1;
1948                                 break;
1949                         }
1950                 }
1951                 event_notifier_priv->pub->parent->has_enablers_without_bytecode =
1952                         has_enablers_without_bytecode;
1953
1954                 /* Enable filters */
1955                 cds_list_for_each_entry(runtime,
1956                                 &event_notifier_priv->pub->parent->filter_bytecode_runtime_head, node) {
1957                         lttng_bytecode_filter_sync_state(runtime);
1958                 }
1959
1960                 /* Enable captures. */
1961                 cds_list_for_each_entry(runtime,
1962                                 &event_notifier_priv->pub->capture_bytecode_runtime_head, node) {
1963                         lttng_bytecode_capture_sync_state(runtime);
1964                 }
1965         }
1966         __tracepoint_probe_prune_release_queue();
1967 }
1968
1969 /*
1970  * Apply enablers to session events, adding events to session if need
1971  * be. It is required after each modification applied to an active
1972  * session, and right before session "start".
1973  * "lazy" sync means we only sync if required.
1974  */
1975 static
1976 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1977 {
1978         /* We can skip if session is not active */
1979         if (!session->active)
1980                 return;
1981         lttng_session_sync_event_enablers(session);
1982 }
1983
1984 /*
1985  * Update all sessions with the given app context.
1986  * Called with ust lock held.
1987  * This is invoked when an application context gets loaded/unloaded. It
1988  * ensures the context callbacks are in sync with the application
1989  * context (either app context callbacks, or dummy callbacks).
1990  */
1991 void lttng_ust_context_set_session_provider(const char *name,
1992                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1993                 void (*record)(struct lttng_ctx_field *field,
1994                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1995                         struct lttng_channel *chan),
1996                 void (*get_value)(struct lttng_ctx_field *field,
1997                         struct lttng_ctx_value *value))
1998 {
1999         struct lttng_ust_session_private *session_priv;
2000
2001         cds_list_for_each_entry(session_priv, &sessions, node) {
2002                 struct lttng_channel *chan;
2003                 struct lttng_ust_event_recorder_private *event_recorder_priv;
2004                 int ret;
2005
2006                 ret = lttng_ust_context_set_provider_rcu(&session_priv->ctx,
2007                                 name, get_size, record, get_value);
2008                 if (ret)
2009                         abort();
2010                 cds_list_for_each_entry(chan, &session_priv->chan_head, node) {
2011                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
2012                                         name, get_size, record, get_value);
2013                         if (ret)
2014                                 abort();
2015                 }
2016                 cds_list_for_each_entry(event_recorder_priv, &session_priv->events_head, node) {
2017                         ret = lttng_ust_context_set_provider_rcu(&event_recorder_priv->pub->ctx,
2018                                         name, get_size, record, get_value);
2019                         if (ret)
2020                                 abort();
2021                 }
2022         }
2023 }
2024
2025 /*
2026  * Update all event_notifier groups with the given app context.
2027  * Called with ust lock held.
2028  * This is invoked when an application context gets loaded/unloaded. It
2029  * ensures the context callbacks are in sync with the application
2030  * context (either app context callbacks, or dummy callbacks).
2031  */
2032 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
2033                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
2034                 void (*record)(struct lttng_ctx_field *field,
2035                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
2036                         struct lttng_channel *chan),
2037                 void (*get_value)(struct lttng_ctx_field *field,
2038                         struct lttng_ctx_value *value))
2039 {
2040         struct lttng_event_notifier_group *event_notifier_group;
2041
2042         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2043                 int ret;
2044
2045                 ret = lttng_ust_context_set_provider_rcu(
2046                                 &event_notifier_group->ctx,
2047                                 name, get_size, record, get_value);
2048                 if (ret)
2049                         abort();
2050         }
2051 }