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

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Holds LTTng per-session event registry.
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <stdio.h>
  11 #include <assert.h>
  12 #include <errno.h>
  13 #include <limits.h>
  14 #include <pthread.h>
  15 #include <sys/shm.h>
  16 #include <sys/ipc.h>
  17 #include <stdint.h>
  18 #include <stddef.h>
  19 #include <inttypes.h>
  20 #include <time.h>
  21 #include <stdbool.h>
  22 #include <unistd.h>
  23 #include <dlfcn.h>
  24 #include <lttng/ust-endian.h>
  25
  26 #include <urcu/arch.h>
  27 #include <urcu/compiler.h>
  28 #include <urcu/hlist.h>
  29 #include <urcu/list.h>
  30 #include <urcu/uatomic.h>
  31
  32 #include <lttng/tracepoint.h>
  33 #include <lttng/ust-events.h>
  34
  35 #include "common/logging.h"
  36 #include "common/macros.h"
  37 #include <lttng/ust-ctl.h>
  38 #include "common/ustcomm.h"
  39 #include "common/ust-fd.h"
  40 #include "common/dynamic-type.h"
  41 #include "common/ust-context-provider.h"
  42 #include "lttng-ust-uuid.h"
  43
  44 #include "common/tracepoint.h"
  45 #include "common/strutils.h"
  46 #include "lttng-bytecode.h"
  47 #include "lttng-tracer.h"
  48 #include "lttng-tracer-core.h"
  49 #include "lttng-ust-statedump.h"
  50 #include "context-internal.h"
  51 #include "lib/lttng-ust/events.h"
  52 #include "common/ringbuffer/shm.h"
  53 #include "common/ringbuffer/frontend_types.h"
  54 #include "common/ringbuffer/frontend.h"
  55 #include "common/counter/counter.h"
  56 #include "common/jhash.h"
  57 #include <lttng/ust-abi.h>
  58 #include "context-provider-internal.h"
  59
  60 /*
  61  * All operations within this file are called by the communication
  62  * thread, under ust_lock protection.
  63  */
  64
  65 static CDS_LIST_HEAD(sessions);
  66 static CDS_LIST_HEAD(event_notifier_groups);
  67
  68 struct cds_list_head *lttng_get_sessions(void)
  69 {
  70         return &sessions;
  71 }
  72
  73 static void _lttng_event_destroy(struct lttng_ust_event_common *event);
  74 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  75
  76 static
  77 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session);
  78 static
  79 void lttng_session_sync_event_enablers(struct lttng_ust_session *session);
  80 static
  81 void lttng_event_notifier_group_sync_enablers(
  82                 struct lttng_event_notifier_group *event_notifier_group);
  83 static
  84 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  85
  86 bool lttng_ust_validate_event_name(const struct lttng_ust_event_desc *desc)
  87 {
  88         if (strlen(desc->probe_desc->provider_name) + 1 +
  89                         strlen(desc->event_name) >= LTTNG_UST_ABI_SYM_NAME_LEN)
  90                 return false;
  91         return true;
  92 }
  93
  94 void lttng_ust_format_event_name(const struct lttng_ust_event_desc *desc,
  95                 char *name)
  96 {
  97         strcpy(name, desc->probe_desc->provider_name);
  98         strcat(name, ":");
  99         strcat(name, desc->event_name);
 100 }
 101
 102 /*
 103  * Called with ust lock held.
 104  */
 105 int lttng_session_active(void)
 106 {
 107         struct lttng_ust_session_private *iter;
 108
 109         cds_list_for_each_entry(iter, &sessions, node) {
 110                 if (iter->pub->active)
 111                         return 1;
 112         }
 113         return 0;
 114 }
 115
 116 static
 117 int lttng_loglevel_match(int loglevel,
 118                 unsigned int has_loglevel,
 119                 enum lttng_ust_abi_loglevel_type req_type,
 120                 int req_loglevel)
 121 {
 122         if (!has_loglevel)
 123                 loglevel = TRACE_DEFAULT;
 124         switch (req_type) {
 125         case LTTNG_UST_ABI_LOGLEVEL_RANGE:
 126                 if (loglevel <= req_loglevel
 127                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 128                         return 1;
 129                 else
 130                         return 0;
 131         case LTTNG_UST_ABI_LOGLEVEL_SINGLE:
 132                 if (loglevel == req_loglevel
 133                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 134                         return 1;
 135                 else
 136                         return 0;
 137         case LTTNG_UST_ABI_LOGLEVEL_ALL:
 138         default:
 139                 if (loglevel <= TRACE_DEBUG)
 140                         return 1;
 141                 else
 142                         return 0;
 143         }
 144 }
 145
 146 struct lttng_ust_session *lttng_session_create(void)
 147 {
 148         struct lttng_ust_session *session;
 149         struct lttng_ust_session_private *session_priv;
 150         int i;
 151
 152         session = zmalloc(sizeof(struct lttng_ust_session));
 153         if (!session)
 154                 return NULL;
 155         session->struct_size = sizeof(struct lttng_ust_session);
 156         session_priv = zmalloc(sizeof(struct lttng_ust_session_private));
 157         if (!session_priv) {
 158                 free(session);
 159                 return NULL;
 160         }
 161         session->priv = session_priv;
 162         session_priv->pub = session;
 163         if (lttng_context_init_all(&session->priv->ctx)) {
 164                 free(session_priv);
 165                 free(session);
 166                 return NULL;
 167         }
 168         CDS_INIT_LIST_HEAD(&session->priv->chan_head);
 169         CDS_INIT_LIST_HEAD(&session->priv->events_head);
 170         CDS_INIT_LIST_HEAD(&session->priv->enums_head);
 171         CDS_INIT_LIST_HEAD(&session->priv->enablers_head);
 172         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 173                 CDS_INIT_HLIST_HEAD(&session->priv->events_ht.table[i]);
 174         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 175                 CDS_INIT_HLIST_HEAD(&session->priv->enums_ht.table[i]);
 176         cds_list_add(&session->priv->node, &sessions);
 177         return session;
 178 }
 179
 180 struct lttng_counter *lttng_ust_counter_create(
 181                 const char *counter_transport_name,
 182                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 183 {
 184         struct lttng_counter_transport *counter_transport = NULL;
 185         struct lttng_counter *counter = NULL;
 186
 187         counter_transport = lttng_counter_transport_find(counter_transport_name);
 188         if (!counter_transport)
 189                 goto notransport;
 190         counter = zmalloc(sizeof(struct lttng_counter));
 191         if (!counter)
 192                 goto nomem;
 193
 194         counter->ops = &counter_transport->ops;
 195         counter->transport = counter_transport;
 196
 197         counter->counter = counter->ops->counter_create(
 198                         number_dimensions, dimensions, 0,
 199                         -1, 0, NULL, false);
 200         if (!counter->counter) {
 201                 goto create_error;
 202         }
 203
 204         return counter;
 205
 206 create_error:
 207         free(counter);
 208 nomem:
 209 notransport:
 210         return NULL;
 211 }
 212
 213 static
 214 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 215 {
 216         counter->ops->counter_destroy(counter->counter);
 217         free(counter);
 218 }
 219
 220 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 221 {
 222         struct lttng_event_notifier_group *event_notifier_group;
 223         int i;
 224
 225         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 226         if (!event_notifier_group)
 227                 return NULL;
 228
 229         /* Add all contexts. */
 230         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 231                 free(event_notifier_group);
 232                 return NULL;
 233         }
 234
 235         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 236         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 237         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 238                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 239
 240         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 241
 242         return event_notifier_group;
 243 }
 244
 245 /*
 246  * Only used internally at session destruction.
 247  */
 248 static
 249 void _lttng_channel_unmap(struct lttng_ust_channel_buffer *lttng_chan)
 250 {
 251         struct lttng_ust_ring_buffer_channel *chan;
 252         struct lttng_ust_shm_handle *handle;
 253
 254         cds_list_del(&lttng_chan->priv->node);
 255         lttng_destroy_context(lttng_chan->priv->ctx);
 256         chan = lttng_chan->priv->rb_chan;
 257         handle = chan->handle;
 258         channel_destroy(chan, handle, 0);
 259         free(lttng_chan->parent);
 260         free(lttng_chan->priv);
 261         free(lttng_chan);
 262 }
 263
 264 static
 265 void register_event(struct lttng_ust_event_common *event)
 266 {
 267         int ret;
 268         const struct lttng_ust_event_desc *desc;
 269         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 270
 271         assert(event->priv->registered == 0);
 272         desc = event->priv->desc;
 273         lttng_ust_format_event_name(desc, name);
 274         ret = lttng_ust_tp_probe_register_queue_release(name,
 275                         desc->probe_callback,
 276                         event, desc->signature);
 277         WARN_ON_ONCE(ret);
 278         if (!ret)
 279                 event->priv->registered = 1;
 280 }
 281
 282 static
 283 void unregister_event(struct lttng_ust_event_common *event)
 284 {
 285         int ret;
 286         const struct lttng_ust_event_desc *desc;
 287         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 288
 289         assert(event->priv->registered == 1);
 290         desc = event->priv->desc;
 291         lttng_ust_format_event_name(desc, name);
 292         ret = lttng_ust_tp_probe_unregister_queue_release(name,
 293                         desc->probe_callback,
 294                         event);
 295         WARN_ON_ONCE(ret);
 296         if (!ret)
 297                 event->priv->registered = 0;
 298 }
 299
 300 static
 301 void _lttng_event_unregister(struct lttng_ust_event_common *event)
 302 {
 303         if (event->priv->registered)
 304                 unregister_event(event);
 305 }
 306
 307 void lttng_session_destroy(struct lttng_ust_session *session)
 308 {
 309         struct lttng_ust_channel_buffer_private *chan, *tmpchan;
 310         struct lttng_ust_event_recorder_private *event_recorder_priv, *tmpevent_recorder_priv;
 311         struct lttng_enum *_enum, *tmp_enum;
 312         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 313
 314         CMM_ACCESS_ONCE(session->active) = 0;
 315         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
 316                 _lttng_event_unregister(event_recorder_priv->parent.pub);
 317         }
 318         lttng_ust_urcu_synchronize_rcu();       /* Wait for in-flight events to complete */
 319         lttng_ust_tp_probe_prune_release_queue();
 320         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 321                         &session->priv->enablers_head, node)
 322                 lttng_event_enabler_destroy(event_enabler);
 323         cds_list_for_each_entry_safe(event_recorder_priv, tmpevent_recorder_priv,
 324                         &session->priv->events_head, node)
 325                 _lttng_event_destroy(event_recorder_priv->parent.pub);
 326         cds_list_for_each_entry_safe(_enum, tmp_enum,
 327                         &session->priv->enums_head, node)
 328                 _lttng_enum_destroy(_enum);
 329         cds_list_for_each_entry_safe(chan, tmpchan, &session->priv->chan_head, node)
 330                 _lttng_channel_unmap(chan->pub);
 331         cds_list_del(&session->priv->node);
 332         lttng_destroy_context(session->priv->ctx);
 333         free(session->priv);
 334         free(session);
 335 }
 336
 337 void lttng_event_notifier_group_destroy(
 338                 struct lttng_event_notifier_group *event_notifier_group)
 339 {
 340         int close_ret;
 341         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 342         struct lttng_ust_event_notifier_private *event_notifier_priv, *tmpevent_notifier_priv;
 343
 344         if (!event_notifier_group) {
 345                 return;
 346         }
 347
 348         cds_list_for_each_entry(event_notifier_priv,
 349                         &event_notifier_group->event_notifiers_head, node)
 350                 _lttng_event_unregister(event_notifier_priv->parent.pub);
 351
 352         lttng_ust_urcu_synchronize_rcu();
 353
 354         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 355                         &event_notifier_group->enablers_head, node)
 356                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 357
 358         cds_list_for_each_entry_safe(event_notifier_priv, tmpevent_notifier_priv,
 359                         &event_notifier_group->event_notifiers_head, node)
 360                 _lttng_event_destroy(event_notifier_priv->parent.pub);
 361
 362         if (event_notifier_group->error_counter)
 363                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 364
 365         /* Close the notification fd to the listener of event_notifiers. */
 366
 367         lttng_ust_lock_fd_tracker();
 368         close_ret = close(event_notifier_group->notification_fd);
 369         if (!close_ret) {
 370                 lttng_ust_delete_fd_from_tracker(
 371                                 event_notifier_group->notification_fd);
 372         } else {
 373                 PERROR("close");
 374                 abort();
 375         }
 376         lttng_ust_unlock_fd_tracker();
 377
 378         cds_list_del(&event_notifier_group->node);
 379         lttng_destroy_context(event_notifier_group->ctx);
 380         free(event_notifier_group);
 381 }
 382
 383 static
 384 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 385 {
 386         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 387         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 388
 389         if (!enabler) {
 390                 return;
 391         }
 392
 393         /* Destroy filter bytecode */
 394         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 395                         &enabler->filter_bytecode_head, node) {
 396                 free(filter_node);
 397         }
 398
 399         /* Destroy excluders */
 400         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 401                         &enabler->excluder_head, node) {
 402                 free(excluder_node);
 403         }
 404 }
 405
 406  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 407 {
 408         if (!event_notifier_enabler) {
 409                 return;
 410         }
 411
 412         cds_list_del(&event_notifier_enabler->node);
 413
 414         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 415
 416         free(event_notifier_enabler);
 417 }
 418
 419 static
 420 int lttng_enum_create(const struct lttng_ust_enum_desc *desc,
 421                 struct lttng_ust_session *session)
 422 {
 423         const char *enum_name = desc->name;
 424         struct lttng_enum *_enum;
 425         struct cds_hlist_head *head;
 426         int ret = 0;
 427         size_t name_len = strlen(enum_name);
 428         uint32_t hash;
 429         int notify_socket;
 430
 431         /* Check if this enum is already registered for this session. */
 432         hash = jhash(enum_name, name_len, 0);
 433         head = &session->priv->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 434
 435         _enum = lttng_ust_enum_get_from_desc(session, desc);
 436         if (_enum) {
 437                 ret = -EEXIST;
 438                 goto exist;
 439         }
 440
 441         notify_socket = lttng_get_notify_socket(session->priv->owner);
 442         if (notify_socket < 0) {
 443                 ret = notify_socket;
 444                 goto socket_error;
 445         }
 446
 447         _enum = zmalloc(sizeof(*_enum));
 448         if (!_enum) {
 449                 ret = -ENOMEM;
 450                 goto cache_error;
 451         }
 452         _enum->session = session;
 453         _enum->desc = desc;
 454
 455         ret = ustcomm_register_enum(notify_socket,
 456                 session->priv->objd,
 457                 enum_name,
 458                 desc->nr_entries,
 459                 desc->entries,
 460                 &_enum->id);
 461         if (ret < 0) {
 462                 DBG("Error (%d) registering enumeration to sessiond", ret);
 463                 goto sessiond_register_error;
 464         }
 465         cds_list_add(&_enum->node, &session->priv->enums_head);
 466         cds_hlist_add_head(&_enum->hlist, head);
 467         return 0;
 468
 469 sessiond_register_error:
 470         free(_enum);
 471 cache_error:
 472 socket_error:
 473 exist:
 474         return ret;
 475 }
 476
 477 static
 478 int lttng_create_enum_check(const struct lttng_ust_type_common *type,
 479                 struct lttng_ust_session *session)
 480 {
 481         switch (type->type) {
 482         case lttng_ust_type_enum:
 483         {
 484                 const struct lttng_ust_enum_desc *enum_desc;
 485                 int ret;
 486
 487                 enum_desc = lttng_ust_get_type_enum(type)->desc;
 488                 ret = lttng_enum_create(enum_desc, session);
 489                 if (ret && ret != -EEXIST) {
 490                         DBG("Unable to create enum error: (%d)", ret);
 491                         return ret;
 492                 }
 493                 break;
 494         }
 495         case lttng_ust_type_dynamic:
 496         {
 497                 const struct lttng_ust_event_field *tag_field_generic;
 498                 const struct lttng_ust_enum_desc *enum_desc;
 499                 int ret;
 500
 501                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 502                 enum_desc = lttng_ust_get_type_enum(tag_field_generic->type)->desc;
 503                 ret = lttng_enum_create(enum_desc, session);
 504                 if (ret && ret != -EEXIST) {
 505                         DBG("Unable to create enum error: (%d)", ret);
 506                         return ret;
 507                 }
 508                 break;
 509         }
 510         default:
 511                 /* TODO: nested types when they become supported. */
 512                 break;
 513         }
 514         return 0;
 515 }
 516
 517 static
 518 int lttng_create_all_event_enums(size_t nr_fields,
 519                 const struct lttng_ust_event_field **event_fields,
 520                 struct lttng_ust_session *session)
 521 {
 522         size_t i;
 523         int ret;
 524
 525         /* For each field, ensure enum is part of the session. */
 526         for (i = 0; i < nr_fields; i++) {
 527                 const struct lttng_ust_type_common *type = event_fields[i]->type;
 528
 529                 ret = lttng_create_enum_check(type, session);
 530                 if (ret)
 531                         return ret;
 532         }
 533         return 0;
 534 }
 535
 536 static
 537 int lttng_create_all_ctx_enums(size_t nr_fields,
 538                 struct lttng_ust_ctx_field *ctx_fields,
 539                 struct lttng_ust_session *session)
 540 {
 541         size_t i;
 542         int ret;
 543
 544         /* For each field, ensure enum is part of the session. */
 545         for (i = 0; i < nr_fields; i++) {
 546                 const struct lttng_ust_type_common *type = ctx_fields[i].event_field->type;
 547
 548                 ret = lttng_create_enum_check(type, session);
 549                 if (ret)
 550                         return ret;
 551         }
 552         return 0;
 553 }
 554
 555 /*
 556  * Ensure that a state-dump will be performed for this session at the end
 557  * of the current handle_message().
 558  */
 559 int lttng_session_statedump(struct lttng_ust_session *session)
 560 {
 561         session->priv->statedump_pending = 1;
 562         lttng_ust_sockinfo_session_enabled(session->priv->owner);
 563         return 0;
 564 }
 565
 566 int lttng_session_enable(struct lttng_ust_session *session)
 567 {
 568         int ret = 0;
 569         struct lttng_ust_channel_buffer_private *chan;
 570         int notify_socket;
 571
 572         if (session->active) {
 573                 ret = -EBUSY;
 574                 goto end;
 575         }
 576
 577         notify_socket = lttng_get_notify_socket(session->priv->owner);
 578         if (notify_socket < 0)
 579                 return notify_socket;
 580
 581         /* Set transient enabler state to "enabled" */
 582         session->priv->tstate = 1;
 583
 584         /* We need to sync enablers with session before activation. */
 585         lttng_session_sync_event_enablers(session);
 586
 587         /*
 588          * Snapshot the number of events per channel to know the type of header
 589          * we need to use.
 590          */
 591         cds_list_for_each_entry(chan, &session->priv->chan_head, node) {
 592                 struct lttng_ust_ctx *ctx;
 593                 struct lttng_ust_ctx_field *fields = NULL;
 594                 size_t nr_fields = 0;
 595                 uint32_t chan_id;
 596
 597                 /* don't change it if session stop/restart */
 598                 if (chan->header_type)
 599                         continue;
 600                 ctx = chan->ctx;
 601                 if (ctx) {
 602                         nr_fields = ctx->nr_fields;
 603                         fields = ctx->fields;
 604                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 605                                 session);
 606                         if (ret < 0) {
 607                                 DBG("Error (%d) adding enum to session", ret);
 608                                 return ret;
 609                         }
 610                 }
 611                 ret = ustcomm_register_channel(notify_socket,
 612                         session,
 613                         session->priv->objd,
 614                         chan->parent.objd,
 615                         nr_fields,
 616                         fields,
 617                         &chan_id,
 618                         &chan->header_type);
 619                 if (ret) {
 620                         DBG("Error (%d) registering channel to sessiond", ret);
 621                         return ret;
 622                 }
 623                 if (chan_id != chan->id) {
 624                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 625                                 chan_id, chan->id);
 626                         return -EINVAL;
 627                 }
 628         }
 629
 630         /* Set atomically the state to "active" */
 631         CMM_ACCESS_ONCE(session->active) = 1;
 632         CMM_ACCESS_ONCE(session->priv->been_active) = 1;
 633
 634         ret = lttng_session_statedump(session);
 635         if (ret)
 636                 return ret;
 637 end:
 638         return ret;
 639 }
 640
 641 int lttng_session_disable(struct lttng_ust_session *session)
 642 {
 643         int ret = 0;
 644
 645         if (!session->active) {
 646                 ret = -EBUSY;
 647                 goto end;
 648         }
 649         /* Set atomically the state to "inactive" */
 650         CMM_ACCESS_ONCE(session->active) = 0;
 651
 652         /* Set transient enabler state to "disabled" */
 653         session->priv->tstate = 0;
 654         lttng_session_sync_event_enablers(session);
 655 end:
 656         return ret;
 657 }
 658
 659 int lttng_channel_enable(struct lttng_ust_channel_common *lttng_channel)
 660 {
 661         int ret = 0;
 662
 663         if (lttng_channel->enabled) {
 664                 ret = -EBUSY;
 665                 goto end;
 666         }
 667         /* Set transient enabler state to "enabled" */
 668         lttng_channel->priv->tstate = 1;
 669         lttng_session_sync_event_enablers(lttng_channel->session);
 670         /* Set atomically the state to "enabled" */
 671         CMM_ACCESS_ONCE(lttng_channel->enabled) = 1;
 672 end:
 673         return ret;
 674 }
 675
 676 int lttng_channel_disable(struct lttng_ust_channel_common *lttng_channel)
 677 {
 678         int ret = 0;
 679
 680         if (!lttng_channel->enabled) {
 681                 ret = -EBUSY;
 682                 goto end;
 683         }
 684         /* Set atomically the state to "disabled" */
 685         CMM_ACCESS_ONCE(lttng_channel->enabled) = 0;
 686         /* Set transient enabler state to "enabled" */
 687         lttng_channel->priv->tstate = 0;
 688         lttng_session_sync_event_enablers(lttng_channel->session);
 689 end:
 690         return ret;
 691 }
 692
 693 static inline
 694 struct cds_hlist_head *borrow_hash_table_bucket(
 695                 struct cds_hlist_head *hash_table,
 696                 unsigned int hash_table_size,
 697                 const struct lttng_ust_event_desc *desc)
 698 {
 699         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 700         size_t name_len;
 701         uint32_t hash;
 702
 703         lttng_ust_format_event_name(desc, name);
 704         name_len = strlen(name);
 705
 706         hash = jhash(name, name_len, 0);
 707         return &hash_table[hash & (hash_table_size - 1)];
 708 }
 709
 710 /*
 711  * Supports event creation while tracing session is active.
 712  */
 713 static
 714 int lttng_event_recorder_create(const struct lttng_ust_event_desc *desc,
 715                 struct lttng_ust_channel_buffer *chan)
 716 {
 717         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 718         struct lttng_ust_event_recorder *event_recorder;
 719         struct lttng_ust_event_recorder_private *event_recorder_priv;
 720         struct lttng_ust_session *session = chan->parent->session;
 721         struct cds_hlist_head *head;
 722         int ret = 0;
 723         int notify_socket, loglevel;
 724         const char *uri;
 725
 726         head = borrow_hash_table_bucket(chan->parent->session->priv->events_ht.table,
 727                 LTTNG_UST_EVENT_HT_SIZE, desc);
 728
 729         notify_socket = lttng_get_notify_socket(session->priv->owner);
 730         if (notify_socket < 0) {
 731                 ret = notify_socket;
 732                 goto socket_error;
 733         }
 734
 735         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 736                         session);
 737         if (ret < 0) {
 738                 DBG("Error (%d) adding enum to session", ret);
 739                 goto create_enum_error;
 740         }
 741
 742         /*
 743          * Check if loglevel match. Refuse to connect event if not.
 744          */
 745         event_recorder = zmalloc(sizeof(struct lttng_ust_event_recorder));
 746         if (!event_recorder) {
 747                 ret = -ENOMEM;
 748                 goto cache_error;
 749         }
 750         event_recorder->struct_size = sizeof(struct lttng_ust_event_recorder);
 751
 752         event_recorder->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 753         if (!event_recorder->parent) {
 754                 ret = -ENOMEM;
 755                 goto parent_error;
 756         }
 757         event_recorder->parent->struct_size = sizeof(struct lttng_ust_event_common);
 758         event_recorder->parent->type = LTTNG_UST_EVENT_TYPE_RECORDER;
 759         event_recorder->parent->child = event_recorder;
 760
 761         event_recorder_priv = zmalloc(sizeof(struct lttng_ust_event_recorder_private));
 762         if (!event_recorder_priv) {
 763                 ret = -ENOMEM;
 764                 goto priv_error;
 765         }
 766         event_recorder->priv = event_recorder_priv;
 767         event_recorder_priv->pub = event_recorder;
 768         event_recorder->parent->priv = &event_recorder_priv->parent;
 769         event_recorder_priv->parent.pub = event_recorder->parent;
 770
 771         event_recorder->chan = chan;
 772
 773         /* Event will be enabled by enabler sync. */
 774         event_recorder->parent->run_filter = lttng_ust_interpret_event_filter;
 775         event_recorder->parent->enabled = 0;
 776         event_recorder->parent->priv->registered = 0;
 777         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->filter_bytecode_runtime_head);
 778         CDS_INIT_LIST_HEAD(&event_recorder->parent->priv->enablers_ref_head);
 779         event_recorder->parent->priv->desc = desc;
 780
 781         if (desc->loglevel)
 782                 loglevel = *(*desc->loglevel);
 783         else
 784                 loglevel = TRACE_DEFAULT;
 785         if (desc->model_emf_uri)
 786                 uri = *(desc->model_emf_uri);
 787         else
 788                 uri = NULL;
 789
 790         lttng_ust_format_event_name(desc, name);
 791
 792         /* Fetch event ID from sessiond */
 793         ret = ustcomm_register_event(notify_socket,
 794                 session,
 795                 session->priv->objd,
 796                 chan->priv->parent.objd,
 797                 name,
 798                 loglevel,
 799                 desc->signature,
 800                 desc->nr_fields,
 801                 desc->fields,
 802                 uri,
 803                 &event_recorder->priv->id);
 804         if (ret < 0) {
 805                 DBG("Error (%d) registering event to sessiond", ret);
 806                 goto sessiond_register_error;
 807         }
 808
 809         cds_list_add(&event_recorder_priv->node, &chan->parent->session->priv->events_head);
 810         cds_hlist_add_head(&event_recorder_priv->hlist, head);
 811         return 0;
 812
 813 sessiond_register_error:
 814         free(event_recorder_priv);
 815 priv_error:
 816         free(event_recorder->parent);
 817 parent_error:
 818         free(event_recorder);
 819 cache_error:
 820 create_enum_error:
 821 socket_error:
 822         return ret;
 823 }
 824
 825 static
 826 int lttng_event_notifier_create(const struct lttng_ust_event_desc *desc,
 827                 uint64_t token, uint64_t error_counter_index,
 828                 struct lttng_event_notifier_group *event_notifier_group)
 829 {
 830         struct lttng_ust_event_notifier *event_notifier;
 831         struct lttng_ust_event_notifier_private *event_notifier_priv;
 832         struct cds_hlist_head *head;
 833         int ret = 0;
 834
 835         /*
 836          * Get the hashtable bucket the created lttng_event_notifier object
 837          * should be inserted.
 838          */
 839         head = borrow_hash_table_bucket(
 840                 event_notifier_group->event_notifiers_ht.table,
 841                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 842
 843         event_notifier = zmalloc(sizeof(struct lttng_ust_event_notifier));
 844         if (!event_notifier) {
 845                 ret = -ENOMEM;
 846                 goto error;
 847         }
 848         event_notifier->struct_size = sizeof(struct lttng_ust_event_notifier);
 849
 850         event_notifier->parent = zmalloc(sizeof(struct lttng_ust_event_common));
 851         if (!event_notifier->parent) {
 852                 ret = -ENOMEM;
 853                 goto parent_error;
 854         }
 855         event_notifier->parent->struct_size = sizeof(struct lttng_ust_event_common);
 856         event_notifier->parent->type = LTTNG_UST_EVENT_TYPE_NOTIFIER;
 857         event_notifier->parent->child = event_notifier;
 858
 859         event_notifier_priv = zmalloc(sizeof(struct lttng_ust_event_notifier_private));
 860         if (!event_notifier_priv) {
 861                 ret = -ENOMEM;
 862                 goto priv_error;
 863         }
 864         event_notifier->priv = event_notifier_priv;
 865         event_notifier_priv->pub = event_notifier;
 866         event_notifier->parent->priv = &event_notifier_priv->parent;
 867         event_notifier_priv->parent.pub = event_notifier->parent;
 868
 869         event_notifier_priv->group = event_notifier_group;
 870         event_notifier_priv->parent.user_token = token;
 871         event_notifier_priv->error_counter_index = error_counter_index;
 872
 873         /* Event notifier will be enabled by enabler sync. */
 874         event_notifier->parent->run_filter = lttng_ust_interpret_event_filter;
 875         event_notifier->parent->enabled = 0;
 876         event_notifier_priv->parent.registered = 0;
 877
 878         CDS_INIT_LIST_HEAD(&event_notifier->parent->priv->filter_bytecode_runtime_head);
 879         CDS_INIT_LIST_HEAD(&event_notifier->priv->capture_bytecode_runtime_head);
 880         CDS_INIT_LIST_HEAD(&event_notifier_priv->parent.enablers_ref_head);
 881         event_notifier_priv->parent.desc = desc;
 882         event_notifier->notification_send = lttng_event_notifier_notification_send;
 883
 884         cds_list_add(&event_notifier_priv->node,
 885                         &event_notifier_group->event_notifiers_head);
 886         cds_hlist_add_head(&event_notifier_priv->hlist, head);
 887
 888         return 0;
 889
 890 priv_error:
 891         free(event_notifier->parent);
 892 parent_error:
 893         free(event_notifier);
 894 error:
 895         return ret;
 896 }
 897
 898 static
 899 int lttng_desc_match_star_glob_enabler(const struct lttng_ust_event_desc *desc,
 900                 struct lttng_enabler *enabler)
 901 {
 902         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 903         int loglevel = 0;
 904         unsigned int has_loglevel = 0;
 905
 906         lttng_ust_format_event_name(desc, name);
 907         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 908         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 909                         name, SIZE_MAX))
 910                 return 0;
 911         if (desc->loglevel) {
 912                 loglevel = *(*desc->loglevel);
 913                 has_loglevel = 1;
 914         }
 915         if (!lttng_loglevel_match(loglevel,
 916                         has_loglevel,
 917                         enabler->event_param.loglevel_type,
 918                         enabler->event_param.loglevel))
 919                 return 0;
 920         return 1;
 921 }
 922
 923 static
 924 int lttng_desc_match_event_enabler(const struct lttng_ust_event_desc *desc,
 925                 struct lttng_enabler *enabler)
 926 {
 927         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 928         int loglevel = 0;
 929         unsigned int has_loglevel = 0;
 930
 931         lttng_ust_format_event_name(desc, name);
 932         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 933         if (strcmp(name, enabler->event_param.name))
 934                 return 0;
 935         if (desc->loglevel) {
 936                 loglevel = *(*desc->loglevel);
 937                 has_loglevel = 1;
 938         }
 939         if (!lttng_loglevel_match(loglevel,
 940                         has_loglevel,
 941                         enabler->event_param.loglevel_type,
 942                         enabler->event_param.loglevel))
 943                 return 0;
 944         return 1;
 945 }
 946
 947 static
 948 int lttng_desc_match_enabler(const struct lttng_ust_event_desc *desc,
 949                 struct lttng_enabler *enabler)
 950 {
 951         switch (enabler->format_type) {
 952         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 953         {
 954                 struct lttng_ust_excluder_node *excluder;
 955
 956                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 957                         return 0;
 958                 }
 959
 960                 /*
 961                  * If the matching event matches with an excluder,
 962                  * return 'does not match'
 963                  */
 964                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 965                         int count;
 966
 967                         for (count = 0; count < excluder->excluder.count; count++) {
 968                                 int len;
 969                                 char *excluder_name;
 970
 971                                 excluder_name = (char *) (excluder->excluder.names)
 972                                                 + count * LTTNG_UST_ABI_SYM_NAME_LEN;
 973                                 len = strnlen(excluder_name, LTTNG_UST_ABI_SYM_NAME_LEN);
 974                                 if (len > 0) {
 975                                         char name[LTTNG_UST_ABI_SYM_NAME_LEN];
 976
 977                                         lttng_ust_format_event_name(desc, name);
 978                                         if (strutils_star_glob_match(excluder_name, len, name, SIZE_MAX)) {
 979                                                 return 0;
 980                                         }
 981                                 }
 982                         }
 983                 }
 984                 return 1;
 985         }
 986         case LTTNG_ENABLER_FORMAT_EVENT:
 987                 return lttng_desc_match_event_enabler(desc, enabler);
 988         default:
 989                 return -EINVAL;
 990         }
 991 }
 992
 993 static
 994 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 995                 struct lttng_ust_event_recorder *event_recorder)
 996 {
 997         if (lttng_desc_match_enabler(event_recorder->parent->priv->desc,
 998                         lttng_event_enabler_as_enabler(event_enabler))
 999                         && event_recorder->chan == event_enabler->chan)
1000                 return 1;
1001         else
1002                 return 0;
1003 }
1004
1005 static
1006 int lttng_event_notifier_enabler_match_event_notifier(
1007                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1008                 struct lttng_ust_event_notifier *event_notifier)
1009 {
1010         int desc_matches = lttng_desc_match_enabler(event_notifier->priv->parent.desc,
1011                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1012
1013         if (desc_matches && event_notifier->priv->group == event_notifier_enabler->group &&
1014                         event_notifier->priv->parent.user_token == event_notifier_enabler->user_token)
1015                 return 1;
1016         else
1017                 return 0;
1018 }
1019
1020 static
1021 struct lttng_enabler_ref *lttng_enabler_ref(
1022                 struct cds_list_head *enabler_ref_list,
1023                 struct lttng_enabler *enabler)
1024 {
1025         struct lttng_enabler_ref *enabler_ref;
1026
1027         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1028                 if (enabler_ref->ref == enabler)
1029                         return enabler_ref;
1030         }
1031         return NULL;
1032 }
1033
1034 /*
1035  * Create struct lttng_event if it is missing and present in the list of
1036  * tracepoint probes.
1037  */
1038 static
1039 void lttng_create_event_recorder_if_missing(struct lttng_event_enabler *event_enabler)
1040 {
1041         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1042         struct lttng_ust_registered_probe *reg_probe;
1043         const struct lttng_ust_event_desc *desc;
1044         struct lttng_ust_event_recorder_private *event_recorder_priv;
1045         int i;
1046         struct cds_list_head *probe_list;
1047
1048         probe_list = lttng_get_probe_list_head();
1049         /*
1050          * For each probe event, if we find that a probe event matches
1051          * our enabler, create an associated lttng_event if not
1052          * already present.
1053          */
1054         cds_list_for_each_entry(reg_probe, probe_list, head) {
1055                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1056
1057                 for (i = 0; i < probe_desc->nr_events; i++) {
1058                         int ret;
1059                         bool found = false;
1060                         struct cds_hlist_head *head;
1061                         struct cds_hlist_node *node;
1062
1063                         desc = probe_desc->event_desc[i];
1064                         if (!lttng_desc_match_enabler(desc,
1065                                         lttng_event_enabler_as_enabler(event_enabler)))
1066                                 continue;
1067
1068                         head = borrow_hash_table_bucket(
1069                                 session->priv->events_ht.table,
1070                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1071
1072                         cds_hlist_for_each_entry(event_recorder_priv, node, head, hlist) {
1073                                 if (event_recorder_priv->parent.desc == desc
1074                                                 && event_recorder_priv->pub->chan == event_enabler->chan) {
1075                                         found = true;
1076                                         break;
1077                                 }
1078                         }
1079                         if (found)
1080                                 continue;
1081
1082                         /*
1083                          * We need to create an event for this
1084                          * event probe.
1085                          */
1086                         ret = lttng_event_recorder_create(probe_desc->event_desc[i],
1087                                         event_enabler->chan);
1088                         if (ret) {
1089                                 DBG("Unable to create event \"%s:%s\", error %d\n",
1090                                         probe_desc->provider_name,
1091                                         probe_desc->event_desc[i]->event_name, ret);
1092                         }
1093                 }
1094         }
1095 }
1096
1097 static
1098 void probe_provider_event_for_each(const struct lttng_ust_probe_desc *provider_desc,
1099                 void (*event_func)(struct lttng_ust_event_common *event))
1100 {
1101         struct cds_hlist_node *node, *tmp_node;
1102         struct cds_list_head *sessionsp;
1103         unsigned int i;
1104
1105         /* Get handle on list of sessions. */
1106         sessionsp = lttng_get_sessions();
1107
1108         /*
1109          * Iterate over all events in the probe provider descriptions and
1110          * sessions to queue the unregistration of the events.
1111          */
1112         for (i = 0; i < provider_desc->nr_events; i++) {
1113                 const struct lttng_ust_event_desc *event_desc;
1114                 struct lttng_event_notifier_group *event_notifier_group;
1115                 struct lttng_ust_event_recorder_private *event_recorder_priv;
1116                 struct lttng_ust_event_notifier_private *event_notifier_priv;
1117                 struct lttng_ust_session_private *session_priv;
1118                 struct cds_hlist_head *head;
1119
1120                 event_desc = provider_desc->event_desc[i];
1121
1122                 /*
1123                  * Iterate over all session to find the current event
1124                  * description.
1125                  */
1126                 cds_list_for_each_entry(session_priv, sessionsp, node) {
1127                         /*
1128                          * Get the list of events in the hashtable bucket and
1129                          * iterate to find the event matching this descriptor.
1130                          */
1131                         head = borrow_hash_table_bucket(
1132                                 session_priv->events_ht.table,
1133                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1134
1135                         cds_hlist_for_each_entry_safe(event_recorder_priv, node, tmp_node, head, hlist) {
1136                                 if (event_desc == event_recorder_priv->parent.desc) {
1137                                         event_func(event_recorder_priv->parent.pub);
1138                                         break;
1139                                 }
1140                         }
1141                 }
1142
1143                 /*
1144                  * Iterate over all event_notifier groups to find the current event
1145                  * description.
1146                  */
1147                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1148                         /*
1149                          * Get the list of event_notifiers in the hashtable bucket and
1150                          * iterate to find the event_notifier matching this
1151                          * descriptor.
1152                          */
1153                         head = borrow_hash_table_bucket(
1154                                 event_notifier_group->event_notifiers_ht.table,
1155                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1156
1157                         cds_hlist_for_each_entry_safe(event_notifier_priv, node, tmp_node, head, hlist) {
1158                                 if (event_desc == event_notifier_priv->parent.desc) {
1159                                         event_func(event_notifier_priv->parent.pub);
1160                                         break;
1161                                 }
1162                         }
1163                 }
1164         }
1165 }
1166
1167 static
1168 void _event_enum_destroy(struct lttng_ust_event_common *event)
1169 {
1170
1171         switch (event->type) {
1172         case LTTNG_UST_EVENT_TYPE_RECORDER:
1173         {
1174                 struct lttng_ust_event_recorder *event_recorder = event->child;
1175                 struct lttng_ust_session *session = event_recorder->chan->parent->session;
1176                 unsigned int i;
1177
1178                 /* Destroy enums of the current event. */
1179                 for (i = 0; i < event_recorder->parent->priv->desc->nr_fields; i++) {
1180                         const struct lttng_ust_enum_desc *enum_desc;
1181                         const struct lttng_ust_event_field *field;
1182                         struct lttng_enum *curr_enum;
1183
1184                         field = event_recorder->parent->priv->desc->fields[i];
1185                         switch (field->type->type) {
1186                         case lttng_ust_type_enum:
1187                                 enum_desc = lttng_ust_get_type_enum(field->type)->desc;
1188                                 break;
1189                         default:
1190                                 continue;
1191                         }
1192
1193                         curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1194                         if (curr_enum) {
1195                                 _lttng_enum_destroy(curr_enum);
1196                         }
1197                 }
1198                 break;
1199         }
1200         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1201                 break;
1202         default:
1203                 abort();
1204         }
1205         /* Destroy event. */
1206         _lttng_event_destroy(event);
1207 }
1208
1209 /*
1210  * Iterate over all the UST sessions to unregister and destroy all probes from
1211  * the probe provider descriptor received as argument. Must me called with the
1212  * ust_lock held.
1213  */
1214 void lttng_probe_provider_unregister_events(
1215                 const struct lttng_ust_probe_desc *provider_desc)
1216 {
1217         /*
1218          * Iterate over all events in the probe provider descriptions and sessions
1219          * to queue the unregistration of the events.
1220          */
1221         probe_provider_event_for_each(provider_desc, _lttng_event_unregister);
1222
1223         /* Wait for grace period. */
1224         lttng_ust_urcu_synchronize_rcu();
1225         /* Prune the unregistration queue. */
1226         lttng_ust_tp_probe_prune_release_queue();
1227
1228         /*
1229          * It is now safe to destroy the events and remove them from the event list
1230          * and hashtables.
1231          */
1232         probe_provider_event_for_each(provider_desc, _event_enum_destroy);
1233 }
1234
1235 /*
1236  * Create events associated with an event enabler (if not already present),
1237  * and add backward reference from the event to the enabler.
1238  */
1239 static
1240 int lttng_event_enabler_ref_event_recorders(struct lttng_event_enabler *event_enabler)
1241 {
1242         struct lttng_ust_session *session = event_enabler->chan->parent->session;
1243         struct lttng_ust_event_recorder_private *event_recorder_priv;
1244
1245         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1246                 goto end;
1247
1248         /* First ensure that probe events are created for this enabler. */
1249         lttng_create_event_recorder_if_missing(event_enabler);
1250
1251         /* For each event matching enabler in session event list. */
1252         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1253                 struct lttng_enabler_ref *enabler_ref;
1254
1255                 if (!lttng_event_enabler_match_event(event_enabler, event_recorder_priv->pub))
1256                         continue;
1257
1258                 enabler_ref = lttng_enabler_ref(&event_recorder_priv->parent.enablers_ref_head,
1259                         lttng_event_enabler_as_enabler(event_enabler));
1260                 if (!enabler_ref) {
1261                         /*
1262                          * If no backward ref, create it.
1263                          * Add backward ref from event to enabler.
1264                          */
1265                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1266                         if (!enabler_ref)
1267                                 return -ENOMEM;
1268                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1269                                 event_enabler);
1270                         cds_list_add(&enabler_ref->node,
1271                                 &event_recorder_priv->parent.enablers_ref_head);
1272                 }
1273
1274                 /*
1275                  * Link filter bytecodes if not linked yet.
1276                  */
1277                 lttng_enabler_link_bytecode(event_recorder_priv->parent.desc,
1278                         &session->priv->ctx,
1279                         &event_recorder_priv->parent.filter_bytecode_runtime_head,
1280                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1281
1282                 /* TODO: merge event context. */
1283         }
1284 end:
1285         return 0;
1286 }
1287
1288 /*
1289  * Called at library load: connect the probe on all enablers matching
1290  * this event.
1291  * Called with session mutex held.
1292  */
1293 int lttng_fix_pending_events(void)
1294 {
1295         struct lttng_ust_session_private *session_priv;
1296
1297         cds_list_for_each_entry(session_priv, &sessions, node) {
1298                 lttng_session_lazy_sync_event_enablers(session_priv->pub);
1299         }
1300         return 0;
1301 }
1302
1303 int lttng_fix_pending_event_notifiers(void)
1304 {
1305         struct lttng_event_notifier_group *event_notifier_group;
1306
1307         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1308                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1309         }
1310         return 0;
1311 }
1312
1313 /*
1314  * For each session of the owner thread, execute pending statedump.
1315  * Only dump state for the sessions owned by the caller thread, because
1316  * we don't keep ust_lock across the entire iteration.
1317  */
1318 void lttng_handle_pending_statedump(void *owner)
1319 {
1320         struct lttng_ust_session_private *session_priv;
1321
1322         /* Execute state dump */
1323         do_lttng_ust_statedump(owner);
1324
1325         /* Clear pending state dump */
1326         if (ust_lock()) {
1327                 goto end;
1328         }
1329         cds_list_for_each_entry(session_priv, &sessions, node) {
1330                 if (session_priv->owner != owner)
1331                         continue;
1332                 if (!session_priv->statedump_pending)
1333                         continue;
1334                 session_priv->statedump_pending = 0;
1335         }
1336 end:
1337         ust_unlock();
1338         return;
1339 }
1340
1341 static
1342 void _lttng_event_destroy(struct lttng_ust_event_common *event)
1343 {
1344         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1345
1346         lttng_free_event_filter_runtime(event);
1347         /* Free event enabler refs */
1348         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1349                         &event->priv->enablers_ref_head, node)
1350                 free(enabler_ref);
1351
1352         switch (event->type) {
1353         case LTTNG_UST_EVENT_TYPE_RECORDER:
1354         {
1355                 struct lttng_ust_event_recorder *event_recorder = event->child;
1356
1357                 /* Remove from event list. */
1358                 cds_list_del(&event_recorder->priv->node);
1359                 /* Remove from event hash table. */
1360                 cds_hlist_del(&event_recorder->priv->hlist);
1361
1362                 lttng_destroy_context(event_recorder->priv->ctx);
1363                 free(event_recorder->parent);
1364                 free(event_recorder->priv);
1365                 free(event_recorder);
1366                 break;
1367         }
1368         case LTTNG_UST_EVENT_TYPE_NOTIFIER:
1369         {
1370                 struct lttng_ust_event_notifier *event_notifier = event->child;
1371
1372                 /* Remove from event list. */
1373                 cds_list_del(&event_notifier->priv->node);
1374                 /* Remove from event hash table. */
1375                 cds_hlist_del(&event_notifier->priv->hlist);
1376
1377                 free(event_notifier->priv);
1378                 free(event_notifier->parent);
1379                 free(event_notifier);
1380                 break;
1381         }
1382         default:
1383                 abort();
1384         }
1385 }
1386
1387 static
1388 void _lttng_enum_destroy(struct lttng_enum *_enum)
1389 {
1390         cds_list_del(&_enum->node);
1391         cds_hlist_del(&_enum->hlist);
1392         free(_enum);
1393 }
1394
1395 void lttng_ust_abi_events_exit(void)
1396 {
1397         struct lttng_ust_session_private *session_priv, *tmpsession_priv;
1398
1399         cds_list_for_each_entry_safe(session_priv, tmpsession_priv, &sessions, node)
1400                 lttng_session_destroy(session_priv->pub);
1401 }
1402
1403 /*
1404  * Enabler management.
1405  */
1406 struct lttng_event_enabler *lttng_event_enabler_create(
1407                 enum lttng_enabler_format_type format_type,
1408                 struct lttng_ust_abi_event *event_param,
1409                 struct lttng_ust_channel_buffer *chan)
1410 {
1411         struct lttng_event_enabler *event_enabler;
1412
1413         event_enabler = zmalloc(sizeof(*event_enabler));
1414         if (!event_enabler)
1415                 return NULL;
1416         event_enabler->base.format_type = format_type;
1417         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1418         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1419         memcpy(&event_enabler->base.event_param, event_param,
1420                 sizeof(event_enabler->base.event_param));
1421         event_enabler->chan = chan;
1422         /* ctx left NULL */
1423         event_enabler->base.enabled = 0;
1424         cds_list_add(&event_enabler->node, &event_enabler->chan->parent->session->priv->enablers_head);
1425         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1426
1427         return event_enabler;
1428 }
1429
1430 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1431                 struct lttng_event_notifier_group *event_notifier_group,
1432                 enum lttng_enabler_format_type format_type,
1433                 struct lttng_ust_abi_event_notifier *event_notifier_param)
1434 {
1435         struct lttng_event_notifier_enabler *event_notifier_enabler;
1436
1437         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1438         if (!event_notifier_enabler)
1439                 return NULL;
1440         event_notifier_enabler->base.format_type = format_type;
1441         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1442         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1443         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1444
1445         event_notifier_enabler->user_token = event_notifier_param->event.token;
1446         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1447         event_notifier_enabler->num_captures = 0;
1448
1449         memcpy(&event_notifier_enabler->base.event_param.name,
1450                 event_notifier_param->event.name,
1451                 sizeof(event_notifier_enabler->base.event_param.name));
1452         event_notifier_enabler->base.event_param.instrumentation =
1453                 event_notifier_param->event.instrumentation;
1454         event_notifier_enabler->base.event_param.loglevel =
1455                 event_notifier_param->event.loglevel;
1456         event_notifier_enabler->base.event_param.loglevel_type =
1457                 event_notifier_param->event.loglevel_type;
1458
1459         event_notifier_enabler->base.enabled = 0;
1460         event_notifier_enabler->group = event_notifier_group;
1461
1462         cds_list_add(&event_notifier_enabler->node,
1463                         &event_notifier_group->enablers_head);
1464
1465         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1466
1467         return event_notifier_enabler;
1468 }
1469
1470 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1471 {
1472         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1473         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1474
1475         return 0;
1476 }
1477
1478 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1479 {
1480         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1481         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1482
1483         return 0;
1484 }
1485
1486 static
1487 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1488                 struct lttng_ust_bytecode_node **bytecode)
1489 {
1490         (*bytecode)->enabler = enabler;
1491         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1492         /* Take ownership of bytecode */
1493         *bytecode = NULL;
1494 }
1495
1496 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1497                 struct lttng_ust_bytecode_node **bytecode)
1498 {
1499         _lttng_enabler_attach_filter_bytecode(
1500                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1501
1502         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1503         return 0;
1504 }
1505
1506 static
1507 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1508                 struct lttng_ust_excluder_node **excluder)
1509 {
1510         (*excluder)->enabler = enabler;
1511         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1512         /* Take ownership of excluder */
1513         *excluder = NULL;
1514 }
1515
1516 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1517                 struct lttng_ust_excluder_node **excluder)
1518 {
1519         _lttng_enabler_attach_exclusion(
1520                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1521
1522         lttng_session_lazy_sync_event_enablers(event_enabler->chan->parent->session);
1523         return 0;
1524 }
1525
1526 int lttng_event_notifier_enabler_enable(
1527                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1528 {
1529         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1530         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1531
1532         return 0;
1533 }
1534
1535 int lttng_event_notifier_enabler_disable(
1536                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1537 {
1538         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1539         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1540
1541         return 0;
1542 }
1543
1544 int lttng_event_notifier_enabler_attach_filter_bytecode(
1545                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1546                 struct lttng_ust_bytecode_node **bytecode)
1547 {
1548         _lttng_enabler_attach_filter_bytecode(
1549                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1550                 bytecode);
1551
1552         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1553         return 0;
1554 }
1555
1556 int lttng_event_notifier_enabler_attach_capture_bytecode(
1557                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1558                 struct lttng_ust_bytecode_node **bytecode)
1559 {
1560         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1561                         event_notifier_enabler);
1562         cds_list_add_tail(&(*bytecode)->node,
1563                         &event_notifier_enabler->capture_bytecode_head);
1564         /* Take ownership of bytecode */
1565         *bytecode = NULL;
1566         event_notifier_enabler->num_captures++;
1567
1568         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1569         return 0;
1570 }
1571
1572 int lttng_event_notifier_enabler_attach_exclusion(
1573                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1574                 struct lttng_ust_excluder_node **excluder)
1575 {
1576         _lttng_enabler_attach_exclusion(
1577                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1578                 excluder);
1579
1580         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1581         return 0;
1582 }
1583
1584 int lttng_attach_context(struct lttng_ust_abi_context *context_param,
1585                 union lttng_ust_abi_args *uargs,
1586                 struct lttng_ust_ctx **ctx, struct lttng_ust_session *session)
1587 {
1588         /*
1589          * We cannot attach a context after trace has been started for a
1590          * session because the metadata does not allow expressing this
1591          * information outside of the original channel scope.
1592          */
1593         if (session->priv->been_active)
1594                 return -EPERM;
1595
1596         switch (context_param->ctx) {
1597         case LTTNG_UST_ABI_CONTEXT_PTHREAD_ID:
1598                 return lttng_add_pthread_id_to_ctx(ctx);
1599         case LTTNG_UST_ABI_CONTEXT_PERF_THREAD_COUNTER:
1600         {
1601                 struct lttng_ust_abi_perf_counter_ctx *perf_ctx_param;
1602
1603                 perf_ctx_param = &context_param->u.perf_counter;
1604                 return lttng_add_perf_counter_to_ctx(
1605                         perf_ctx_param->type,
1606                         perf_ctx_param->config,
1607                         perf_ctx_param->name,
1608                         ctx);
1609         }
1610         case LTTNG_UST_ABI_CONTEXT_VTID:
1611                 return lttng_add_vtid_to_ctx(ctx);
1612         case LTTNG_UST_ABI_CONTEXT_VPID:
1613                 return lttng_add_vpid_to_ctx(ctx);
1614         case LTTNG_UST_ABI_CONTEXT_PROCNAME:
1615                 return lttng_add_procname_to_ctx(ctx);
1616         case LTTNG_UST_ABI_CONTEXT_IP:
1617                 return lttng_add_ip_to_ctx(ctx);
1618         case LTTNG_UST_ABI_CONTEXT_CPU_ID:
1619                 return lttng_add_cpu_id_to_ctx(ctx);
1620         case LTTNG_UST_ABI_CONTEXT_APP_CONTEXT:
1621                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1622                         ctx);
1623         case LTTNG_UST_ABI_CONTEXT_CGROUP_NS:
1624                 return lttng_add_cgroup_ns_to_ctx(ctx);
1625         case LTTNG_UST_ABI_CONTEXT_IPC_NS:
1626                 return lttng_add_ipc_ns_to_ctx(ctx);
1627         case LTTNG_UST_ABI_CONTEXT_MNT_NS:
1628                 return lttng_add_mnt_ns_to_ctx(ctx);
1629         case LTTNG_UST_ABI_CONTEXT_NET_NS:
1630                 return lttng_add_net_ns_to_ctx(ctx);
1631         case LTTNG_UST_ABI_CONTEXT_PID_NS:
1632                 return lttng_add_pid_ns_to_ctx(ctx);
1633         case LTTNG_UST_ABI_CONTEXT_TIME_NS:
1634                 return lttng_add_time_ns_to_ctx(ctx);
1635         case LTTNG_UST_ABI_CONTEXT_USER_NS:
1636                 return lttng_add_user_ns_to_ctx(ctx);
1637         case LTTNG_UST_ABI_CONTEXT_UTS_NS:
1638                 return lttng_add_uts_ns_to_ctx(ctx);
1639         case LTTNG_UST_ABI_CONTEXT_VUID:
1640                 return lttng_add_vuid_to_ctx(ctx);
1641         case LTTNG_UST_ABI_CONTEXT_VEUID:
1642                 return lttng_add_veuid_to_ctx(ctx);
1643         case LTTNG_UST_ABI_CONTEXT_VSUID:
1644                 return lttng_add_vsuid_to_ctx(ctx);
1645         case LTTNG_UST_ABI_CONTEXT_VGID:
1646                 return lttng_add_vgid_to_ctx(ctx);
1647         case LTTNG_UST_ABI_CONTEXT_VEGID:
1648                 return lttng_add_vegid_to_ctx(ctx);
1649         case LTTNG_UST_ABI_CONTEXT_VSGID:
1650                 return lttng_add_vsgid_to_ctx(ctx);
1651         default:
1652                 return -EINVAL;
1653         }
1654 }
1655
1656 int lttng_event_enabler_attach_context(
1657                 struct lttng_event_enabler *enabler __attribute__((unused)),
1658                 struct lttng_ust_abi_context *context_param __attribute__((unused)))
1659 {
1660         return -ENOSYS;
1661 }
1662
1663 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1664 {
1665         if (!event_enabler) {
1666                 return;
1667         }
1668         cds_list_del(&event_enabler->node);
1669
1670         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1671
1672         lttng_destroy_context(event_enabler->ctx);
1673         free(event_enabler);
1674 }
1675
1676 /*
1677  * lttng_session_sync_event_enablers should be called just before starting a
1678  * session.
1679  */
1680 static
1681 void lttng_session_sync_event_enablers(struct lttng_ust_session *session)
1682 {
1683         struct lttng_event_enabler *event_enabler;
1684         struct lttng_ust_event_recorder_private *event_recorder_priv;
1685
1686         cds_list_for_each_entry(event_enabler, &session->priv->enablers_head, node)
1687                 lttng_event_enabler_ref_event_recorders(event_enabler);
1688         /*
1689          * For each event, if at least one of its enablers is enabled,
1690          * and its channel and session transient states are enabled, we
1691          * enable the event, else we disable it.
1692          */
1693         cds_list_for_each_entry(event_recorder_priv, &session->priv->events_head, node) {
1694                 struct lttng_enabler_ref *enabler_ref;
1695                 struct lttng_ust_bytecode_runtime *runtime;
1696                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1697                 int nr_filters = 0;
1698
1699                 /* Enable events */
1700                 cds_list_for_each_entry(enabler_ref,
1701                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1702                         if (enabler_ref->ref->enabled) {
1703                                 enabled = 1;
1704                                 break;
1705                         }
1706                 }
1707                 /*
1708                  * Enabled state is based on union of enablers, with
1709                  * intesection of session and channel transient enable
1710                  * states.
1711                  */
1712                 enabled = enabled && session->priv->tstate && event_recorder_priv->pub->chan->priv->parent.tstate;
1713
1714                 CMM_STORE_SHARED(event_recorder_priv->pub->parent->enabled, enabled);
1715                 /*
1716                  * Sync tracepoint registration with event enabled
1717                  * state.
1718                  */
1719                 if (enabled) {
1720                         if (!event_recorder_priv->parent.registered)
1721                                 register_event(event_recorder_priv->parent.pub);
1722                 } else {
1723                         if (event_recorder_priv->parent.registered)
1724                                 unregister_event(event_recorder_priv->parent.pub);
1725                 }
1726
1727                 /* Check if has enablers without bytecode enabled */
1728                 cds_list_for_each_entry(enabler_ref,
1729                                 &event_recorder_priv->parent.enablers_ref_head, node) {
1730                         if (enabler_ref->ref->enabled
1731                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1732                                 has_enablers_without_filter_bytecode = 1;
1733                                 break;
1734                         }
1735                 }
1736                 event_recorder_priv->parent.has_enablers_without_filter_bytecode =
1737                         has_enablers_without_filter_bytecode;
1738
1739                 /* Enable filters */
1740                 cds_list_for_each_entry(runtime,
1741                                 &event_recorder_priv->parent.filter_bytecode_runtime_head, node) {
1742                         lttng_bytecode_sync_state(runtime);
1743                         nr_filters++;
1744                 }
1745                 CMM_STORE_SHARED(event_recorder_priv->parent.pub->eval_filter,
1746                         !(has_enablers_without_filter_bytecode || !nr_filters));
1747         }
1748         lttng_ust_tp_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(const struct lttng_ust_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_ust_registered_probe *reg_probe;
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(reg_probe, probe_list, head) {
1770                 const struct lttng_ust_probe_desc *probe_desc = reg_probe->desc;
1771
1772                 for (i = 0; i < probe_desc->nr_events; i++) {
1773                         int ret;
1774                         bool found = false;
1775                         const struct lttng_ust_event_desc *desc;
1776                         struct lttng_ust_event_notifier_private *event_notifier_priv;
1777                         struct cds_hlist_head *head;
1778                         struct cds_hlist_node *node;
1779
1780                         desc = probe_desc->event_desc[i];
1781
1782                         if (!lttng_desc_match_enabler(desc,
1783                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1784                                 continue;
1785
1786                         /*
1787                          * Given the current event_notifier group, get the bucket that
1788                          * the target event_notifier would be if it was already
1789                          * created.
1790                          */
1791                         head = borrow_hash_table_bucket(
1792                                 event_notifier_group->event_notifiers_ht.table,
1793                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1794
1795                         cds_hlist_for_each_entry(event_notifier_priv, node, head, hlist) {
1796                                 /*
1797                                  * Check if event_notifier already exists by checking
1798                                  * if the event_notifier and enabler share the same
1799                                  * description and id.
1800                                  */
1801                                 if (event_notifier_priv->parent.desc == desc &&
1802                                                 event_notifier_priv->parent.user_token == event_notifier_enabler->user_token) {
1803                                         found = true;
1804                                         break;
1805                                 }
1806                         }
1807
1808                         if (found)
1809                                 continue;
1810
1811                         /* Check that the probe supports event notifiers, else report the error. */
1812                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1813                                 ERR("Probe \"%s\" contains event \"%s:%s\" which matches an enabled event notifier, "
1814                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1815                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1816                                         "this event will not generate any notification.",
1817                                         probe_desc->provider_name,
1818                                         probe_desc->provider_name, desc->event_name,
1819                                         probe_desc->major,
1820                                         probe_desc->minor);
1821                                 continue;
1822                         }
1823                         /*
1824                          * We need to create a event_notifier for this event probe.
1825                          */
1826                         ret = lttng_event_notifier_create(desc,
1827                                 event_notifier_enabler->user_token,
1828                                 event_notifier_enabler->error_counter_index,
1829                                 event_notifier_group);
1830                         if (ret) {
1831                                 DBG("Unable to create event_notifier \"%s:%s\", error %d\n",
1832                                         probe_desc->provider_name,
1833                                         probe_desc->event_desc[i]->event_name, ret);
1834                         }
1835                 }
1836         }
1837 }
1838
1839 /*
1840  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1841  */
1842 static
1843 int lttng_event_notifier_enabler_ref_event_notifiers(
1844                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1845 {
1846         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1847         struct lttng_ust_event_notifier_private *event_notifier_priv;
1848
1849          /*
1850           * Only try to create event_notifiers for enablers that are enabled, the user
1851           * might still be attaching filter or exclusion to the
1852           * event_notifier_enabler.
1853           */
1854         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1855                 goto end;
1856
1857         /* First, ensure that probe event_notifiers are created for this enabler. */
1858         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1859
1860         /* Link the created event_notifier with its associated enabler. */
1861         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1862                 struct lttng_enabler_ref *enabler_ref;
1863
1864                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier_priv->pub))
1865                         continue;
1866
1867                 enabler_ref = lttng_enabler_ref(&event_notifier_priv->parent.enablers_ref_head,
1868                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1869                 if (!enabler_ref) {
1870                         /*
1871                          * If no backward ref, create it.
1872                          * Add backward ref from event_notifier to enabler.
1873                          */
1874                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1875                         if (!enabler_ref)
1876                                 return -ENOMEM;
1877
1878                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1879                                 event_notifier_enabler);
1880                         cds_list_add(&enabler_ref->node,
1881                                 &event_notifier_priv->parent.enablers_ref_head);
1882                 }
1883
1884                 /*
1885                  * Link filter bytecodes if not linked yet.
1886                  */
1887                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1888                         &event_notifier_group->ctx,
1889                         &event_notifier_priv->parent.filter_bytecode_runtime_head,
1890                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1891
1892                 /*
1893                  * Link capture bytecodes if not linked yet.
1894                  */
1895                 lttng_enabler_link_bytecode(event_notifier_priv->parent.desc,
1896                         &event_notifier_group->ctx, &event_notifier_priv->capture_bytecode_runtime_head,
1897                         &event_notifier_enabler->capture_bytecode_head);
1898
1899                 event_notifier_priv->num_captures = event_notifier_enabler->num_captures;
1900         }
1901 end:
1902         return 0;
1903 }
1904
1905 static
1906 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1907 {
1908         struct lttng_event_notifier_enabler *event_notifier_enabler;
1909         struct lttng_ust_event_notifier_private *event_notifier_priv;
1910
1911         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1912                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1913
1914         /*
1915          * For each event_notifier, if at least one of its enablers is enabled,
1916          * we enable the event_notifier, else we disable it.
1917          */
1918         cds_list_for_each_entry(event_notifier_priv, &event_notifier_group->event_notifiers_head, node) {
1919                 struct lttng_enabler_ref *enabler_ref;
1920                 struct lttng_ust_bytecode_runtime *runtime;
1921                 int enabled = 0, has_enablers_without_filter_bytecode = 0;
1922                 int nr_filters = 0, nr_captures = 0;
1923
1924                 /* Enable event_notifiers */
1925                 cds_list_for_each_entry(enabler_ref,
1926                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1927                         if (enabler_ref->ref->enabled) {
1928                                 enabled = 1;
1929                                 break;
1930                         }
1931                 }
1932
1933                 CMM_STORE_SHARED(event_notifier_priv->pub->parent->enabled, enabled);
1934                 /*
1935                  * Sync tracepoint registration with event_notifier enabled
1936                  * state.
1937                  */
1938                 if (enabled) {
1939                         if (!event_notifier_priv->parent.registered)
1940                                 register_event(event_notifier_priv->parent.pub);
1941                 } else {
1942                         if (event_notifier_priv->parent.registered)
1943                                 unregister_event(event_notifier_priv->parent.pub);
1944                 }
1945
1946                 /* Check if has enablers without bytecode enabled */
1947                 cds_list_for_each_entry(enabler_ref,
1948                                 &event_notifier_priv->parent.enablers_ref_head, node) {
1949                         if (enabler_ref->ref->enabled
1950                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1951                                 has_enablers_without_filter_bytecode = 1;
1952                                 break;
1953                         }
1954                 }
1955                 event_notifier_priv->parent.has_enablers_without_filter_bytecode =
1956                         has_enablers_without_filter_bytecode;
1957
1958                 /* Enable filters */
1959                 cds_list_for_each_entry(runtime,
1960                                 &event_notifier_priv->parent.filter_bytecode_runtime_head, node) {
1961                         lttng_bytecode_sync_state(runtime);
1962                         nr_filters++;
1963                 }
1964                 CMM_STORE_SHARED(event_notifier_priv->parent.pub->eval_filter,
1965                         !(has_enablers_without_filter_bytecode || !nr_filters));
1966
1967                 /* Enable captures. */
1968                 cds_list_for_each_entry(runtime,
1969                                 &event_notifier_priv->capture_bytecode_runtime_head, node) {
1970                         lttng_bytecode_sync_state(runtime);
1971                         nr_captures++;
1972                 }
1973                 CMM_STORE_SHARED(event_notifier_priv->pub->eval_capture,
1974                                 !!nr_captures);
1975         }
1976         lttng_ust_tp_probe_prune_release_queue();
1977 }
1978
1979 /*
1980  * Apply enablers to session events, adding events to session if need
1981  * be. It is required after each modification applied to an active
1982  * session, and right before session "start".
1983  * "lazy" sync means we only sync if required.
1984  */
1985 static
1986 void lttng_session_lazy_sync_event_enablers(struct lttng_ust_session *session)
1987 {
1988         /* We can skip if session is not active */
1989         if (!session->active)
1990                 return;
1991         lttng_session_sync_event_enablers(session);
1992 }
1993
1994 /*
1995  * Update all sessions with the given app context.
1996  * Called with ust lock held.
1997  * This is invoked when an application context gets loaded/unloaded. It
1998  * ensures the context callbacks are in sync with the application
1999  * context (either app context callbacks, or dummy callbacks).
2000  */
2001 void lttng_ust_context_set_session_provider(const char *name,
2002                 size_t (*get_size)(void *priv, size_t offset),
2003                 void (*record)(void *priv, struct lttng_ust_ring_buffer_ctx *ctx,
2004                         struct lttng_ust_channel_buffer *chan),
2005                 void (*get_value)(void *priv, 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, size_t offset),
2043                 void (*record)(void *priv, struct lttng_ust_ring_buffer_ctx *ctx,
2044                         struct lttng_ust_channel_buffer *chan),
2045                 void (*get_value)(void *priv, struct lttng_ust_ctx_value *value),
2046                 void *priv)
2047 {
2048         struct lttng_event_notifier_group *event_notifier_group;
2049
2050         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
2051                 int ret;
2052
2053                 ret = lttng_ust_context_set_provider_rcu(
2054                                 &event_notifier_group->ctx,
2055                                 name, get_size, record, get_value, priv);
2056                 if (ret)
2057                         abort();
2058         }
2059 }
2060
2061 int lttng_ust_session_uuid_validate(struct lttng_ust_session *session,
2062                 unsigned char *uuid)
2063 {
2064         if (!session)
2065                 return 0;
2066         /* Compare UUID with session. */
2067         if (session->priv->uuid_set) {
2068                 if (memcmp(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN)) {
2069                         return -1;
2070                 }
2071         } else {
2072                 memcpy(session->priv->uuid, uuid, LTTNG_UST_UUID_LEN);
2073                 session->priv->uuid_set = true;
2074         }
2075         return 0;
2076
2077 }