liblttng-ust/lttng-events.c

   1 /*
   2  * lttng-events.c
   3  *
   4  * Holds LTTng per-session event registry.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _LGPL_SOURCE
  24 #include <stdio.h>
  25 #include <assert.h>
  26 #include <errno.h>
  27 #include <limits.h>
  28 #include <pthread.h>
  29 #include <sys/shm.h>
  30 #include <sys/ipc.h>
  31 #include <stdint.h>
  32 #include <stddef.h>
  33 #include <inttypes.h>
  34 #include <time.h>
  35 #include <stdbool.h>
  36 #include <unistd.h>
  37 #include <lttng/ust-endian.h>
  38
  39 #include <urcu-bp.h>
  40 #include <urcu/arch.h>
  41 #include <urcu/compiler.h>
  42 #include <urcu/hlist.h>
  43 #include <urcu/list.h>
  44 #include <urcu/uatomic.h>
  45
  46 #include <lttng/tracepoint.h>
  47 #include <lttng/ust-events.h>
  48
  49 #include <usterr-signal-safe.h>
  50 #include <helper.h>
  51 #include <lttng/ust-ctl.h>
  52 #include <ust-comm.h>
  53 #include <ust-fd.h>
  54 #include <lttng/ust-dynamic-type.h>
  55 #include <lttng/ust-context-provider.h>
  56 #include "error.h"
  57 #include "compat.h"
  58 #include "lttng-ust-uuid.h"
  59
  60 #include "tracepoint-internal.h"
  61 #include "string-utils.h"
  62 #include "lttng-bytecode.h"
  63 #include "lttng-tracer.h"
  64 #include "lttng-tracer-core.h"
  65 #include "lttng-ust-statedump.h"
  66 #include "context-internal.h"
  67 #include "ust-events-internal.h"
  68 #include "wait.h"
  69 #include "../libringbuffer/shm.h"
  70 #include "jhash.h"
  71 #include <lttng/ust-abi.h>
  72
  73 /*
  74  * All operations within this file are called by the communication
  75  * thread, under ust_lock protection.
  76  */
  77
  78 static CDS_LIST_HEAD(sessions);
  79 static CDS_LIST_HEAD(event_notifier_groups);
  80
  81 struct cds_list_head *_lttng_get_sessions(void)
  82 {
  83         return &sessions;
  84 }
  85
  86 static void _lttng_event_destroy(struct lttng_event *event);
  87 static void _lttng_event_notifier_destroy(
  88                 struct lttng_event_notifier *event_notifier);
  89 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  90
  91 static
  92 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  93 static
  94 void lttng_session_sync_event_enablers(struct lttng_session *session);
  95 static
  96 void lttng_event_notifier_group_sync_enablers(
  97                 struct lttng_event_notifier_group *event_notifier_group);
  98 static
  99 void lttng_enabler_destroy(struct lttng_enabler *enabler);
 100
 101 /*
 102  * Called with ust lock held.
 103  */
 104 int lttng_session_active(void)
 105 {
 106         struct lttng_session *iter;
 107
 108         cds_list_for_each_entry(iter, &sessions, node) {
 109                 if (iter->active)
 110                         return 1;
 111         }
 112         return 0;
 113 }
 114
 115 static
 116 int lttng_loglevel_match(int loglevel,
 117                 unsigned int has_loglevel,
 118                 enum lttng_ust_loglevel_type req_type,
 119                 int req_loglevel)
 120 {
 121         if (!has_loglevel)
 122                 loglevel = TRACE_DEFAULT;
 123         switch (req_type) {
 124         case LTTNG_UST_LOGLEVEL_RANGE:
 125                 if (loglevel <= req_loglevel
 126                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 127                         return 1;
 128                 else
 129                         return 0;
 130         case LTTNG_UST_LOGLEVEL_SINGLE:
 131                 if (loglevel == req_loglevel
 132                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 133                         return 1;
 134                 else
 135                         return 0;
 136         case LTTNG_UST_LOGLEVEL_ALL:
 137         default:
 138                 if (loglevel <= TRACE_DEBUG)
 139                         return 1;
 140                 else
 141                         return 0;
 142         }
 143 }
 144
 145 void synchronize_trace(void)
 146 {
 147         synchronize_rcu();
 148 }
 149
 150 struct lttng_session *lttng_session_create(void)
 151 {
 152         struct lttng_session *session;
 153         int i;
 154
 155         session = zmalloc(sizeof(struct lttng_session));
 156         if (!session)
 157                 return NULL;
 158         if (lttng_context_init_all(&session->ctx)) {
 159                 free(session);
 160                 return NULL;
 161         }
 162         CDS_INIT_LIST_HEAD(&session->chan_head);
 163         CDS_INIT_LIST_HEAD(&session->events_head);
 164         CDS_INIT_LIST_HEAD(&session->enums_head);
 165         CDS_INIT_LIST_HEAD(&session->enablers_head);
 166         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 167                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 168         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 169                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 170         cds_list_add(&session->node, &sessions);
 171         return session;
 172 }
 173
 174 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 175 {
 176         struct lttng_event_notifier_group *event_notifier_group;
 177         int i;
 178
 179         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 180         if (!event_notifier_group)
 181                 return NULL;
 182
 183         /* Add all contexts. */
 184         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 185                 free(event_notifier_group);
 186                 return NULL;
 187         }
 188
 189         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 190         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 191         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 192                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 193
 194         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 195
 196         return event_notifier_group;
 197 }
 198
 199 /*
 200  * Only used internally at session destruction.
 201  */
 202 static
 203 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 204 {
 205         struct channel *chan;
 206         struct lttng_ust_shm_handle *handle;
 207
 208         cds_list_del(&lttng_chan->node);
 209         lttng_destroy_context(lttng_chan->ctx);
 210         chan = lttng_chan->chan;
 211         handle = lttng_chan->handle;
 212         /*
 213          * note: lttng_chan is private data contained within handle. It
 214          * will be freed along with the handle.
 215          */
 216         channel_destroy(chan, handle, 0);
 217 }
 218
 219 static
 220 void register_event(struct lttng_event *event)
 221 {
 222         int ret;
 223         const struct lttng_event_desc *desc;
 224
 225         assert(event->registered == 0);
 226         desc = event->desc;
 227         ret = __tracepoint_probe_register_queue_release(desc->name,
 228                         desc->probe_callback,
 229                         event, desc->signature);
 230         WARN_ON_ONCE(ret);
 231         if (!ret)
 232                 event->registered = 1;
 233 }
 234
 235 static
 236 void register_event_notifier(struct lttng_event_notifier *event_notifier)
 237 {
 238         int ret;
 239         const struct lttng_event_desc *desc;
 240
 241         assert(event_notifier->registered == 0);
 242         desc = event_notifier->desc;
 243         ret = __tracepoint_probe_register_queue_release(desc->name,
 244                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 245         WARN_ON_ONCE(ret);
 246         if (!ret)
 247                 event_notifier->registered = 1;
 248 }
 249
 250 static
 251 void unregister_event(struct lttng_event *event)
 252 {
 253         int ret;
 254         const struct lttng_event_desc *desc;
 255
 256         assert(event->registered == 1);
 257         desc = event->desc;
 258         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 259                         desc->probe_callback,
 260                         event);
 261         WARN_ON_ONCE(ret);
 262         if (!ret)
 263                 event->registered = 0;
 264 }
 265
 266 static
 267 void unregister_event_notifier(struct lttng_event_notifier *event_notifier)
 268 {
 269         int ret;
 270         const struct lttng_event_desc *desc;
 271
 272         assert(event_notifier->registered == 1);
 273         desc = event_notifier->desc;
 274         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 275                 desc->u.ext.event_notifier_callback, event_notifier);
 276         WARN_ON_ONCE(ret);
 277         if (!ret)
 278                 event_notifier->registered = 0;
 279 }
 280
 281 /*
 282  * Only used internally at session destruction.
 283  */
 284 static
 285 void _lttng_event_unregister(struct lttng_event *event)
 286 {
 287         if (event->registered)
 288                 unregister_event(event);
 289 }
 290
 291 /*
 292  * Only used internally at session destruction.
 293  */
 294 static
 295 void _lttng_event_notifier_unregister(struct lttng_event_notifier *event_notifier)
 296 {
 297         if (event_notifier->registered)
 298                 unregister_event_notifier(event_notifier);
 299 }
 300
 301 void lttng_session_destroy(struct lttng_session *session)
 302 {
 303         struct lttng_channel *chan, *tmpchan;
 304         struct lttng_event *event, *tmpevent;
 305         struct lttng_enum *_enum, *tmp_enum;
 306         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 307
 308         CMM_ACCESS_ONCE(session->active) = 0;
 309         cds_list_for_each_entry(event, &session->events_head, node) {
 310                 _lttng_event_unregister(event);
 311         }
 312         synchronize_trace();    /* Wait for in-flight events to complete */
 313         __tracepoint_probe_prune_release_queue();
 314         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 315                         &session->enablers_head, node)
 316                 lttng_event_enabler_destroy(event_enabler);
 317         cds_list_for_each_entry_safe(event, tmpevent,
 318                         &session->events_head, node)
 319                 _lttng_event_destroy(event);
 320         cds_list_for_each_entry_safe(_enum, tmp_enum,
 321                         &session->enums_head, node)
 322                 _lttng_enum_destroy(_enum);
 323         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 324                 _lttng_channel_unmap(chan);
 325         cds_list_del(&session->node);
 326         lttng_destroy_context(session->ctx);
 327         free(session);
 328 }
 329
 330 void lttng_event_notifier_group_destroy(
 331                 struct lttng_event_notifier_group *event_notifier_group)
 332 {
 333         int close_ret;
 334         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 335         struct lttng_event_notifier *notifier, *tmpnotifier;
 336
 337         if (!event_notifier_group) {
 338                 return;
 339         }
 340
 341         cds_list_for_each_entry(notifier,
 342                         &event_notifier_group->event_notifiers_head, node)
 343                 _lttng_event_notifier_unregister(notifier);
 344
 345         synchronize_trace();
 346
 347         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 348                         &event_notifier_group->enablers_head, node)
 349                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 350
 351         cds_list_for_each_entry_safe(notifier, tmpnotifier,
 352                         &event_notifier_group->event_notifiers_head, node)
 353                 _lttng_event_notifier_destroy(notifier);
 354
 355         /* Close the notification fd to the listener of event notifiers. */
 356
 357         lttng_ust_lock_fd_tracker();
 358         close_ret = close(event_notifier_group->notification_fd);
 359         if (!close_ret) {
 360                 lttng_ust_delete_fd_from_tracker(
 361                                 event_notifier_group->notification_fd);
 362         } else {
 363                 PERROR("close");
 364                 abort();
 365         }
 366         lttng_ust_unlock_fd_tracker();
 367
 368         cds_list_del(&event_notifier_group->node);
 369
 370         free(event_notifier_group);
 371 }
 372
 373 static
 374 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 375 {
 376         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 377         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 378
 379         if (!enabler) {
 380                 return;
 381         }
 382
 383         /* Destroy filter bytecode */
 384         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 385                         &enabler->filter_bytecode_head, node) {
 386                 free(filter_node);
 387         }
 388
 389         /* Destroy excluders */
 390         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 391                         &enabler->excluder_head, node) {
 392                 free(excluder_node);
 393         }
 394 }
 395
 396  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 397 {
 398         if (!event_notifier_enabler) {
 399                 return;
 400         }
 401
 402         cds_list_del(&event_notifier_enabler->node);
 403
 404         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 405
 406         free(event_notifier_enabler);
 407 }
 408
 409 static
 410 int lttng_enum_create(const struct lttng_enum_desc *desc,
 411                 struct lttng_session *session)
 412 {
 413         const char *enum_name = desc->name;
 414         struct lttng_enum *_enum;
 415         struct cds_hlist_head *head;
 416         int ret = 0;
 417         size_t name_len = strlen(enum_name);
 418         uint32_t hash;
 419         int notify_socket;
 420
 421         /* Check if this enum is already registered for this session. */
 422         hash = jhash(enum_name, name_len, 0);
 423         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 424
 425         _enum = lttng_ust_enum_get_from_desc(session, desc);
 426         if (_enum) {
 427                 ret = -EEXIST;
 428                 goto exist;
 429         }
 430
 431         notify_socket = lttng_get_notify_socket(session->owner);
 432         if (notify_socket < 0) {
 433                 ret = notify_socket;
 434                 goto socket_error;
 435         }
 436
 437         _enum = zmalloc(sizeof(*_enum));
 438         if (!_enum) {
 439                 ret = -ENOMEM;
 440                 goto cache_error;
 441         }
 442         _enum->session = session;
 443         _enum->desc = desc;
 444
 445         ret = ustcomm_register_enum(notify_socket,
 446                 session->objd,
 447                 enum_name,
 448                 desc->nr_entries,
 449                 desc->entries,
 450                 &_enum->id);
 451         if (ret < 0) {
 452                 DBG("Error (%d) registering enumeration to sessiond", ret);
 453                 goto sessiond_register_error;
 454         }
 455         cds_list_add(&_enum->node, &session->enums_head);
 456         cds_hlist_add_head(&_enum->hlist, head);
 457         return 0;
 458
 459 sessiond_register_error:
 460         free(_enum);
 461 cache_error:
 462 socket_error:
 463 exist:
 464         return ret;
 465 }
 466
 467 static
 468 int lttng_create_enum_check(const struct lttng_type *type,
 469                 struct lttng_session *session)
 470 {
 471         switch (type->atype) {
 472         case atype_enum:
 473         {
 474                 const struct lttng_enum_desc *enum_desc;
 475                 int ret;
 476
 477                 enum_desc = type->u.legacy.basic.enumeration.desc;
 478                 ret = lttng_enum_create(enum_desc, session);
 479                 if (ret && ret != -EEXIST) {
 480                         DBG("Unable to create enum error: (%d)", ret);
 481                         return ret;
 482                 }
 483                 break;
 484         }
 485         case atype_enum_nestable:
 486         {
 487                 const struct lttng_enum_desc *enum_desc;
 488                 int ret;
 489
 490                 enum_desc = type->u.enum_nestable.desc;
 491                 ret = lttng_enum_create(enum_desc, session);
 492                 if (ret && ret != -EEXIST) {
 493                         DBG("Unable to create enum error: (%d)", ret);
 494                         return ret;
 495                 }
 496                 break;
 497         }
 498         case atype_dynamic:
 499         {
 500                 const struct lttng_event_field *tag_field_generic;
 501                 const struct lttng_enum_desc *enum_desc;
 502                 int ret;
 503
 504                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 505                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 506                 ret = lttng_enum_create(enum_desc, session);
 507                 if (ret && ret != -EEXIST) {
 508                         DBG("Unable to create enum error: (%d)", ret);
 509                         return ret;
 510                 }
 511                 break;
 512         }
 513         default:
 514                 /* TODO: nested types when they become supported. */
 515                 break;
 516         }
 517         return 0;
 518 }
 519
 520 static
 521 int lttng_create_all_event_enums(size_t nr_fields,
 522                 const struct lttng_event_field *event_fields,
 523                 struct lttng_session *session)
 524 {
 525         size_t i;
 526         int ret;
 527
 528         /* For each field, ensure enum is part of the session. */
 529         for (i = 0; i < nr_fields; i++) {
 530                 const struct lttng_type *type = &event_fields[i].type;
 531
 532                 ret = lttng_create_enum_check(type, session);
 533                 if (ret)
 534                         return ret;
 535         }
 536         return 0;
 537 }
 538
 539 static
 540 int lttng_create_all_ctx_enums(size_t nr_fields,
 541                 const struct lttng_ctx_field *ctx_fields,
 542                 struct lttng_session *session)
 543 {
 544         size_t i;
 545         int ret;
 546
 547         /* For each field, ensure enum is part of the session. */
 548         for (i = 0; i < nr_fields; i++) {
 549                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 550
 551                 ret = lttng_create_enum_check(type, session);
 552                 if (ret)
 553                         return ret;
 554         }
 555         return 0;
 556 }
 557
 558 /*
 559  * Ensure that a state-dump will be performed for this session at the end
 560  * of the current handle_message().
 561  */
 562 int lttng_session_statedump(struct lttng_session *session)
 563 {
 564         session->statedump_pending = 1;
 565         lttng_ust_sockinfo_session_enabled(session->owner);
 566         return 0;
 567 }
 568
 569 int lttng_session_enable(struct lttng_session *session)
 570 {
 571         int ret = 0;
 572         struct lttng_channel *chan;
 573         int notify_socket;
 574
 575         if (session->active) {
 576                 ret = -EBUSY;
 577                 goto end;
 578         }
 579
 580         notify_socket = lttng_get_notify_socket(session->owner);
 581         if (notify_socket < 0)
 582                 return notify_socket;
 583
 584         /* Set transient enabler state to "enabled" */
 585         session->tstate = 1;
 586
 587         /* We need to sync enablers with session before activation. */
 588         lttng_session_sync_event_enablers(session);
 589
 590         /*
 591          * Snapshot the number of events per channel to know the type of header
 592          * we need to use.
 593          */
 594         cds_list_for_each_entry(chan, &session->chan_head, node) {
 595                 const struct lttng_ctx *ctx;
 596                 const struct lttng_ctx_field *fields = NULL;
 597                 size_t nr_fields = 0;
 598                 uint32_t chan_id;
 599
 600                 /* don't change it if session stop/restart */
 601                 if (chan->header_type)
 602                         continue;
 603                 ctx = chan->ctx;
 604                 if (ctx) {
 605                         nr_fields = ctx->nr_fields;
 606                         fields = ctx->fields;
 607                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 608                                 session);
 609                         if (ret < 0) {
 610                                 DBG("Error (%d) adding enum to session", ret);
 611                                 return ret;
 612                         }
 613                 }
 614                 ret = ustcomm_register_channel(notify_socket,
 615                         session,
 616                         session->objd,
 617                         chan->objd,
 618                         nr_fields,
 619                         fields,
 620                         &chan_id,
 621                         &chan->header_type);
 622                 if (ret) {
 623                         DBG("Error (%d) registering channel to sessiond", ret);
 624                         return ret;
 625                 }
 626                 if (chan_id != chan->id) {
 627                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 628                                 chan_id, chan->id);
 629                         return -EINVAL;
 630                 }
 631         }
 632
 633         /* Set atomically the state to "active" */
 634         CMM_ACCESS_ONCE(session->active) = 1;
 635         CMM_ACCESS_ONCE(session->been_active) = 1;
 636
 637         ret = lttng_session_statedump(session);
 638         if (ret)
 639                 return ret;
 640 end:
 641         return ret;
 642 }
 643
 644 int lttng_session_disable(struct lttng_session *session)
 645 {
 646         int ret = 0;
 647
 648         if (!session->active) {
 649                 ret = -EBUSY;
 650                 goto end;
 651         }
 652         /* Set atomically the state to "inactive" */
 653         CMM_ACCESS_ONCE(session->active) = 0;
 654
 655         /* Set transient enabler state to "disabled" */
 656         session->tstate = 0;
 657         lttng_session_sync_event_enablers(session);
 658 end:
 659         return ret;
 660 }
 661
 662 int lttng_channel_enable(struct lttng_channel *channel)
 663 {
 664         int ret = 0;
 665
 666         if (channel->enabled) {
 667                 ret = -EBUSY;
 668                 goto end;
 669         }
 670         /* Set transient enabler state to "enabled" */
 671         channel->tstate = 1;
 672         lttng_session_sync_event_enablers(channel->session);
 673         /* Set atomically the state to "enabled" */
 674         CMM_ACCESS_ONCE(channel->enabled) = 1;
 675 end:
 676         return ret;
 677 }
 678
 679 int lttng_channel_disable(struct lttng_channel *channel)
 680 {
 681         int ret = 0;
 682
 683         if (!channel->enabled) {
 684                 ret = -EBUSY;
 685                 goto end;
 686         }
 687         /* Set atomically the state to "disabled" */
 688         CMM_ACCESS_ONCE(channel->enabled) = 0;
 689         /* Set transient enabler state to "enabled" */
 690         channel->tstate = 0;
 691         lttng_session_sync_event_enablers(channel->session);
 692 end:
 693         return ret;
 694 }
 695
 696 static inline
 697 struct cds_hlist_head *borrow_hash_table_bucket(
 698                 struct cds_hlist_head *hash_table,
 699                 unsigned int hash_table_size,
 700                 const struct lttng_event_desc *desc)
 701 {
 702         const char *event_name;
 703         size_t name_len;
 704         uint32_t hash;
 705
 706         event_name = desc->name;
 707         name_len = strlen(event_name);
 708
 709         hash = jhash(event_name, name_len, 0);
 710         return &hash_table[hash & (hash_table_size - 1)];
 711 }
 712
 713 /*
 714  * Supports event creation while tracing session is active.
 715  */
 716 static
 717 int lttng_event_create(const struct lttng_event_desc *desc,
 718                 struct lttng_channel *chan)
 719 {
 720         struct lttng_event *event;
 721         struct lttng_session *session = chan->session;
 722         struct cds_hlist_head *head;
 723         int ret = 0;
 724         int notify_socket, loglevel;
 725         const char *uri;
 726
 727         head = borrow_hash_table_bucket(chan->session->events_ht.table,
 728                 LTTNG_UST_EVENT_HT_SIZE, desc);
 729
 730         notify_socket = lttng_get_notify_socket(session->owner);
 731         if (notify_socket < 0) {
 732                 ret = notify_socket;
 733                 goto socket_error;
 734         }
 735
 736         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 737                         session);
 738         if (ret < 0) {
 739                 DBG("Error (%d) adding enum to session", ret);
 740                 goto create_enum_error;
 741         }
 742
 743         /*
 744          * Check if loglevel match. Refuse to connect event if not.
 745          */
 746         event = zmalloc(sizeof(struct lttng_event));
 747         if (!event) {
 748                 ret = -ENOMEM;
 749                 goto cache_error;
 750         }
 751         event->chan = chan;
 752
 753         /* Event will be enabled by enabler sync. */
 754         event->enabled = 0;
 755         event->registered = 0;
 756         CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
 757         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 758         event->desc = desc;
 759
 760         if (desc->loglevel)
 761                 loglevel = *(*event->desc->loglevel);
 762         else
 763                 loglevel = TRACE_DEFAULT;
 764         if (desc->u.ext.model_emf_uri)
 765                 uri = *(desc->u.ext.model_emf_uri);
 766         else
 767                 uri = NULL;
 768
 769         /* Fetch event ID from sessiond */
 770         ret = ustcomm_register_event(notify_socket,
 771                 session,
 772                 session->objd,
 773                 chan->objd,
 774                 desc->name,
 775                 loglevel,
 776                 desc->signature,
 777                 desc->nr_fields,
 778                 desc->fields,
 779                 uri,
 780                 &event->id);
 781         if (ret < 0) {
 782                 DBG("Error (%d) registering event to sessiond", ret);
 783                 goto sessiond_register_error;
 784         }
 785
 786         cds_list_add(&event->node, &chan->session->events_head);
 787         cds_hlist_add_head(&event->hlist, head);
 788         return 0;
 789
 790 sessiond_register_error:
 791         free(event);
 792 cache_error:
 793 create_enum_error:
 794 socket_error:
 795         return ret;
 796 }
 797
 798 static
 799 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 800                 uint64_t token,
 801                 struct lttng_event_notifier_group *event_notifier_group)
 802 {
 803         struct lttng_event_notifier *event_notifier;
 804         struct cds_hlist_head *head;
 805         int ret = 0;
 806
 807         /*
 808          * Get the hashtable bucket the created lttng_event_notifier object
 809          * should be inserted.
 810          */
 811         head = borrow_hash_table_bucket(
 812                 event_notifier_group->event_notifiers_ht.table,
 813                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 814
 815         event_notifier = zmalloc(sizeof(struct lttng_event_notifier));
 816         if (!event_notifier) {
 817                 ret = -ENOMEM;
 818                 goto error;
 819         }
 820
 821         event_notifier->group = event_notifier_group;
 822         event_notifier->user_token = token;
 823
 824         /* Event notifier will be enabled by enabler sync. */
 825         event_notifier->enabled = 0;
 826         event_notifier->registered = 0;
 827
 828         CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
 829         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 830         CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
 831         event_notifier->desc = desc;
 832
 833         cds_list_add(&event_notifier->node,
 834                         &event_notifier_group->event_notifiers_head);
 835         cds_hlist_add_head(&event_notifier->hlist, head);
 836
 837         return 0;
 838
 839 error:
 840         return ret;
 841 }
 842
 843 static
 844 void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
 845 {
 846         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 847
 848         /* Remove from event_notifier list. */
 849         cds_list_del(&event_notifier->node);
 850         /* Remove from event_notifier hash table. */
 851         cds_hlist_del(&event_notifier->hlist);
 852
 853         lttng_free_event_notifier_filter_runtime(event_notifier);
 854
 855         /* Free event_notifier enabler refs */
 856         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 857                         &event_notifier->enablers_ref_head, node)
 858                 free(enabler_ref);
 859         free(event_notifier);
 860 }
 861
 862 static
 863 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 864                 struct lttng_enabler *enabler)
 865 {
 866         int loglevel = 0;
 867         unsigned int has_loglevel = 0;
 868
 869         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 870         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 871                         desc->name, SIZE_MAX))
 872                 return 0;
 873         if (desc->loglevel) {
 874                 loglevel = *(*desc->loglevel);
 875                 has_loglevel = 1;
 876         }
 877         if (!lttng_loglevel_match(loglevel,
 878                         has_loglevel,
 879                         enabler->event_param.loglevel_type,
 880                         enabler->event_param.loglevel))
 881                 return 0;
 882         return 1;
 883 }
 884
 885 static
 886 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 887                 struct lttng_enabler *enabler)
 888 {
 889         int loglevel = 0;
 890         unsigned int has_loglevel = 0;
 891
 892         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 893         if (strcmp(desc->name, enabler->event_param.name))
 894                 return 0;
 895         if (desc->loglevel) {
 896                 loglevel = *(*desc->loglevel);
 897                 has_loglevel = 1;
 898         }
 899         if (!lttng_loglevel_match(loglevel,
 900                         has_loglevel,
 901                         enabler->event_param.loglevel_type,
 902                         enabler->event_param.loglevel))
 903                 return 0;
 904         return 1;
 905 }
 906
 907 static
 908 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 909                 struct lttng_enabler *enabler)
 910 {
 911         switch (enabler->format_type) {
 912         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 913         {
 914                 struct lttng_ust_excluder_node *excluder;
 915
 916                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 917                         return 0;
 918                 }
 919
 920                 /*
 921                  * If the matching event matches with an excluder,
 922                  * return 'does not match'
 923                  */
 924                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 925                         int count;
 926
 927                         for (count = 0; count < excluder->excluder.count; count++) {
 928                                 int len;
 929                                 char *excluder_name;
 930
 931                                 excluder_name = (char *) (excluder->excluder.names)
 932                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 933                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 934                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 935                                         return 0;
 936                         }
 937                 }
 938                 return 1;
 939         }
 940         case LTTNG_ENABLER_FORMAT_EVENT:
 941                 return lttng_desc_match_event_enabler(desc, enabler);
 942         default:
 943                 return -EINVAL;
 944         }
 945 }
 946
 947 static
 948 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 949                 struct lttng_event *event)
 950 {
 951         if (lttng_desc_match_enabler(event->desc,
 952                         lttng_event_enabler_as_enabler(event_enabler))
 953                         && event->chan == event_enabler->chan)
 954                 return 1;
 955         else
 956                 return 0;
 957 }
 958
 959 static
 960 int lttng_event_notifier_enabler_match_event_notifier(
 961                 struct lttng_event_notifier_enabler *event_notifier_enabler,
 962                 struct lttng_event_notifier *event_notifier)
 963 {
 964         int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
 965                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 966
 967         if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
 968                         event_notifier->user_token == event_notifier_enabler->user_token)
 969                 return 1;
 970         else
 971                 return 0;
 972 }
 973
 974 static
 975 struct lttng_enabler_ref *lttng_enabler_ref(
 976                 struct cds_list_head *enabler_ref_list,
 977                 struct lttng_enabler *enabler)
 978 {
 979         struct lttng_enabler_ref *enabler_ref;
 980
 981         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
 982                 if (enabler_ref->ref == enabler)
 983                         return enabler_ref;
 984         }
 985         return NULL;
 986 }
 987
 988 /*
 989  * Create struct lttng_event if it is missing and present in the list of
 990  * tracepoint probes.
 991  */
 992 static
 993 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
 994 {
 995         struct lttng_session *session = event_enabler->chan->session;
 996         struct lttng_probe_desc *probe_desc;
 997         const struct lttng_event_desc *desc;
 998         struct lttng_event *event;
 999         int i;
1000         struct cds_list_head *probe_list;
1001
1002         probe_list = lttng_get_probe_list_head();
1003         /*
1004          * For each probe event, if we find that a probe event matches
1005          * our enabler, create an associated lttng_event if not
1006          * already present.
1007          */
1008         cds_list_for_each_entry(probe_desc, probe_list, head) {
1009                 for (i = 0; i < probe_desc->nr_events; i++) {
1010                         int ret;
1011                         bool found = false;
1012                         struct cds_hlist_head *head;
1013                         struct cds_hlist_node *node;
1014
1015                         desc = probe_desc->event_desc[i];
1016                         if (!lttng_desc_match_enabler(desc,
1017                                         lttng_event_enabler_as_enabler(event_enabler)))
1018                                 continue;
1019
1020                         head = borrow_hash_table_bucket(
1021                                 session->events_ht.table,
1022                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1023
1024                         cds_hlist_for_each_entry(event, node, head, hlist) {
1025                                 if (event->desc == desc
1026                                                 && event->chan == event_enabler->chan) {
1027                                         found = true;
1028                                         break;
1029                                 }
1030                         }
1031                         if (found)
1032                                 continue;
1033
1034                         /*
1035                          * We need to create an event for this
1036                          * event probe.
1037                          */
1038                         ret = lttng_event_create(probe_desc->event_desc[i],
1039                                         event_enabler->chan);
1040                         if (ret) {
1041                                 DBG("Unable to create event %s, error %d\n",
1042                                         probe_desc->event_desc[i]->name, ret);
1043                         }
1044                 }
1045         }
1046 }
1047
1048 static
1049 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1050                 void (*event_func)(struct lttng_session *session,
1051                         struct lttng_event *event),
1052                 void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
1053 {
1054         struct cds_hlist_node *node, *tmp_node;
1055         struct cds_list_head *sessionsp;
1056         unsigned int i;
1057
1058         /* Get handle on list of sessions. */
1059         sessionsp = _lttng_get_sessions();
1060
1061         /*
1062          * Iterate over all events in the probe provider descriptions and
1063          * sessions to queue the unregistration of the events.
1064          */
1065         for (i = 0; i < provider_desc->nr_events; i++) {
1066                 const struct lttng_event_desc *event_desc;
1067                 struct lttng_event_notifier_group *event_notifier_group;
1068                 struct lttng_event_notifier *event_notifier;
1069                 struct lttng_session *session;
1070                 struct cds_hlist_head *head;
1071                 struct lttng_event *event;
1072
1073                 event_desc = provider_desc->event_desc[i];
1074
1075                 /*
1076                  * Iterate over all session to find the current event
1077                  * description.
1078                  */
1079                 cds_list_for_each_entry(session, sessionsp, node) {
1080                         /*
1081                          * Get the list of events in the hashtable bucket and
1082                          * iterate to find the event matching this descriptor.
1083                          */
1084                         head = borrow_hash_table_bucket(
1085                                 session->events_ht.table,
1086                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1087
1088                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1089                                 if (event_desc == event->desc) {
1090                                         event_func(session, event);
1091                                         break;
1092                                 }
1093                         }
1094                 }
1095
1096                 /*
1097                  * Iterate over all event_notifier groups to find the current event
1098                  * description.
1099                  */
1100                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1101                         /*
1102                          * Get the list of event_notifiers in the hashtable bucket and
1103                          * iterate to find the event_notifier matching this
1104                          * descriptor.
1105                          */
1106                         head = borrow_hash_table_bucket(
1107                                 event_notifier_group->event_notifiers_ht.table,
1108                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1109
1110                         cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
1111                                 if (event_desc == event_notifier->desc) {
1112                                         event_notifier_func(event_notifier);
1113                                         break;
1114                                 }
1115                         }
1116                 }
1117         }
1118 }
1119
1120 static
1121 void _unregister_event(struct lttng_session *session,
1122                 struct lttng_event *event)
1123 {
1124         _lttng_event_unregister(event);
1125 }
1126
1127 static
1128 void _event_enum_destroy(struct lttng_session *session,
1129                 struct lttng_event *event)
1130 {
1131         unsigned int i;
1132
1133         /* Destroy enums of the current event. */
1134         for (i = 0; i < event->desc->nr_fields; i++) {
1135                 const struct lttng_enum_desc *enum_desc;
1136                 const struct lttng_event_field *field;
1137                 struct lttng_enum *curr_enum;
1138
1139                 field = &(event->desc->fields[i]);
1140                 switch (field->type.atype) {
1141                 case atype_enum:
1142                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1143                         break;
1144                 case atype_enum_nestable:
1145                         enum_desc = field->type.u.enum_nestable.desc;
1146                         break;
1147                 default:
1148                         continue;
1149                 }
1150
1151                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1152                 if (curr_enum) {
1153                         _lttng_enum_destroy(curr_enum);
1154                 }
1155         }
1156
1157         /* Destroy event. */
1158         _lttng_event_destroy(event);
1159 }
1160
1161 /*
1162  * Iterate over all the UST sessions to unregister and destroy all probes from
1163  * the probe provider descriptor received as argument. Must me called with the
1164  * ust_lock held.
1165  */
1166 void lttng_probe_provider_unregister_events(
1167                 struct lttng_probe_desc *provider_desc)
1168 {
1169         /*
1170          * Iterate over all events in the probe provider descriptions and sessions
1171          * to queue the unregistration of the events.
1172          */
1173         probe_provider_event_for_each(provider_desc, _unregister_event,
1174                 _lttng_event_notifier_unregister);
1175
1176         /* Wait for grace period. */
1177         synchronize_trace();
1178         /* Prune the unregistration queue. */
1179         __tracepoint_probe_prune_release_queue();
1180
1181         /*
1182          * It is now safe to destroy the events and remove them from the event list
1183          * and hashtables.
1184          */
1185         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1186                 _lttng_event_notifier_destroy);
1187 }
1188
1189 /*
1190  * Create events associated with an event enabler (if not already present),
1191  * and add backward reference from the event to the enabler.
1192  */
1193 static
1194 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1195 {
1196         struct lttng_session *session = event_enabler->chan->session;
1197         struct lttng_event *event;
1198
1199         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1200                 goto end;
1201
1202         /* First ensure that probe events are created for this enabler. */
1203         lttng_create_event_if_missing(event_enabler);
1204
1205         /* For each event matching enabler in session event list. */
1206         cds_list_for_each_entry(event, &session->events_head, node) {
1207                 struct lttng_enabler_ref *enabler_ref;
1208
1209                 if (!lttng_event_enabler_match_event(event_enabler, event))
1210                         continue;
1211
1212                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1213                         lttng_event_enabler_as_enabler(event_enabler));
1214                 if (!enabler_ref) {
1215                         /*
1216                          * If no backward ref, create it.
1217                          * Add backward ref from event to enabler.
1218                          */
1219                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1220                         if (!enabler_ref)
1221                                 return -ENOMEM;
1222                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1223                                 event_enabler);
1224                         cds_list_add(&enabler_ref->node,
1225                                 &event->enablers_ref_head);
1226                 }
1227
1228                 /*
1229                  * Link filter bytecodes if not linked yet.
1230                  */
1231                 lttng_enabler_link_bytecode(event->desc,
1232                         &session->ctx,
1233                         &event->filter_bytecode_runtime_head,
1234                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1235
1236                 /* TODO: merge event context. */
1237         }
1238 end:
1239         return 0;
1240 }
1241
1242 /*
1243  * Called at library load: connect the probe on all enablers matching
1244  * this event.
1245  * Called with session mutex held.
1246  */
1247 int lttng_fix_pending_events(void)
1248 {
1249         struct lttng_session *session;
1250
1251         cds_list_for_each_entry(session, &sessions, node) {
1252                 lttng_session_lazy_sync_event_enablers(session);
1253         }
1254         return 0;
1255 }
1256
1257 int lttng_fix_pending_event_notifiers(void)
1258 {
1259         struct lttng_event_notifier_group *event_notifier_group;
1260
1261         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1262                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1263         }
1264         return 0;
1265 }
1266
1267 /*
1268  * For each session of the owner thread, execute pending statedump.
1269  * Only dump state for the sessions owned by the caller thread, because
1270  * we don't keep ust_lock across the entire iteration.
1271  */
1272 void lttng_handle_pending_statedump(void *owner)
1273 {
1274         struct lttng_session *session;
1275
1276         /* Execute state dump */
1277         do_lttng_ust_statedump(owner);
1278
1279         /* Clear pending state dump */
1280         if (ust_lock()) {
1281                 goto end;
1282         }
1283         cds_list_for_each_entry(session, &sessions, node) {
1284                 if (session->owner != owner)
1285                         continue;
1286                 if (!session->statedump_pending)
1287                         continue;
1288                 session->statedump_pending = 0;
1289         }
1290 end:
1291         ust_unlock();
1292         return;
1293 }
1294
1295 /*
1296  * Only used internally at session destruction.
1297  */
1298 static
1299 void _lttng_event_destroy(struct lttng_event *event)
1300 {
1301         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1302
1303         /* Remove from event list. */
1304         cds_list_del(&event->node);
1305         /* Remove from event hash table. */
1306         cds_hlist_del(&event->hlist);
1307
1308         lttng_destroy_context(event->ctx);
1309         lttng_free_event_filter_runtime(event);
1310         /* Free event enabler refs */
1311         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1312                         &event->enablers_ref_head, node)
1313                 free(enabler_ref);
1314         free(event);
1315 }
1316
1317 static
1318 void _lttng_enum_destroy(struct lttng_enum *_enum)
1319 {
1320         cds_list_del(&_enum->node);
1321         cds_hlist_del(&_enum->hlist);
1322         free(_enum);
1323 }
1324
1325 void lttng_ust_events_exit(void)
1326 {
1327         struct lttng_session *session, *tmpsession;
1328
1329         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1330                 lttng_session_destroy(session);
1331 }
1332
1333 /*
1334  * Enabler management.
1335  */
1336 struct lttng_event_enabler *lttng_event_enabler_create(
1337                 enum lttng_enabler_format_type format_type,
1338                 struct lttng_ust_event *event_param,
1339                 struct lttng_channel *chan)
1340 {
1341         struct lttng_event_enabler *event_enabler;
1342
1343         event_enabler = zmalloc(sizeof(*event_enabler));
1344         if (!event_enabler)
1345                 return NULL;
1346         event_enabler->base.format_type = format_type;
1347         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1348         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1349         memcpy(&event_enabler->base.event_param, event_param,
1350                 sizeof(event_enabler->base.event_param));
1351         event_enabler->chan = chan;
1352         /* ctx left NULL */
1353         event_enabler->base.enabled = 0;
1354         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1355         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1356
1357         return event_enabler;
1358 }
1359
1360 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1361                 struct lttng_event_notifier_group *event_notifier_group,
1362                 enum lttng_enabler_format_type format_type,
1363                 struct lttng_ust_event_notifier *event_notifier_param)
1364 {
1365         struct lttng_event_notifier_enabler *event_notifier_enabler;
1366
1367         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1368         if (!event_notifier_enabler)
1369                 return NULL;
1370         event_notifier_enabler->base.format_type = format_type;
1371         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1372         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1373         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1374
1375         event_notifier_enabler->user_token = event_notifier_param->event.token;
1376         event_notifier_enabler->num_captures = 0;
1377
1378         memcpy(&event_notifier_enabler->base.event_param.name,
1379                 event_notifier_param->event.name,
1380                 sizeof(event_notifier_enabler->base.event_param.name));
1381         event_notifier_enabler->base.event_param.instrumentation =
1382                 event_notifier_param->event.instrumentation;
1383         event_notifier_enabler->base.event_param.loglevel =
1384                 event_notifier_param->event.loglevel;
1385         event_notifier_enabler->base.event_param.loglevel_type =
1386                 event_notifier_param->event.loglevel_type;
1387
1388         event_notifier_enabler->base.enabled = 0;
1389         event_notifier_enabler->group = event_notifier_group;
1390
1391         cds_list_add(&event_notifier_enabler->node,
1392                         &event_notifier_group->enablers_head);
1393
1394         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1395
1396         return event_notifier_enabler;
1397 }
1398
1399 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1400 {
1401         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1402         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1403
1404         return 0;
1405 }
1406
1407 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1408 {
1409         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1410         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1411
1412         return 0;
1413 }
1414
1415 static
1416 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1417                 struct lttng_ust_bytecode_node *bytecode)
1418 {
1419         bytecode->enabler = enabler;
1420         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
1421 }
1422
1423 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1424                 struct lttng_ust_bytecode_node *bytecode)
1425 {
1426         _lttng_enabler_attach_filter_bytecode(
1427                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1428
1429         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1430         return 0;
1431 }
1432
1433 static
1434 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1435                 struct lttng_ust_excluder_node *excluder)
1436 {
1437         excluder->enabler = enabler;
1438         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
1439 }
1440
1441 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1442                 struct lttng_ust_excluder_node *excluder)
1443 {
1444         _lttng_enabler_attach_exclusion(
1445                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1446
1447         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1448         return 0;
1449 }
1450
1451 int lttng_event_notifier_enabler_enable(
1452                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1453 {
1454         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1455         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1456
1457         return 0;
1458 }
1459
1460 int lttng_event_notifier_enabler_disable(
1461                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1462 {
1463         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1464         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1465
1466         return 0;
1467 }
1468
1469 int lttng_event_notifier_enabler_attach_filter_bytecode(
1470                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1471                 struct lttng_ust_bytecode_node *bytecode)
1472 {
1473         _lttng_enabler_attach_filter_bytecode(
1474                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1475                 bytecode);
1476
1477         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1478         return 0;
1479 }
1480
1481 int lttng_event_notifier_enabler_attach_capture_bytecode(
1482                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1483                 struct lttng_ust_bytecode_node *bytecode)
1484 {
1485         bytecode->enabler = lttng_event_notifier_enabler_as_enabler(
1486                         event_notifier_enabler);
1487         cds_list_add_tail(&bytecode->node,
1488                         &event_notifier_enabler->capture_bytecode_head);
1489         event_notifier_enabler->num_captures++;
1490
1491         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1492         return 0;
1493 }
1494
1495 int lttng_event_notifier_enabler_attach_exclusion(
1496                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1497                 struct lttng_ust_excluder_node *excluder)
1498 {
1499         _lttng_enabler_attach_exclusion(
1500                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1501                 excluder);
1502
1503         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1504         return 0;
1505 }
1506
1507 int lttng_attach_context(struct lttng_ust_context *context_param,
1508                 union ust_args *uargs,
1509                 struct lttng_ctx **ctx, struct lttng_session *session)
1510 {
1511         /*
1512          * We cannot attach a context after trace has been started for a
1513          * session because the metadata does not allow expressing this
1514          * information outside of the original channel scope.
1515          */
1516         if (session->been_active)
1517                 return -EPERM;
1518
1519         switch (context_param->ctx) {
1520         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1521                 return lttng_add_pthread_id_to_ctx(ctx);
1522         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1523         {
1524                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1525
1526                 perf_ctx_param = &context_param->u.perf_counter;
1527                 return lttng_add_perf_counter_to_ctx(
1528                         perf_ctx_param->type,
1529                         perf_ctx_param->config,
1530                         perf_ctx_param->name,
1531                         ctx);
1532         }
1533         case LTTNG_UST_CONTEXT_VTID:
1534                 return lttng_add_vtid_to_ctx(ctx);
1535         case LTTNG_UST_CONTEXT_VPID:
1536                 return lttng_add_vpid_to_ctx(ctx);
1537         case LTTNG_UST_CONTEXT_PROCNAME:
1538                 return lttng_add_procname_to_ctx(ctx);
1539         case LTTNG_UST_CONTEXT_IP:
1540                 return lttng_add_ip_to_ctx(ctx);
1541         case LTTNG_UST_CONTEXT_CPU_ID:
1542                 return lttng_add_cpu_id_to_ctx(ctx);
1543         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1544                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1545                         ctx);
1546         case LTTNG_UST_CONTEXT_CGROUP_NS:
1547                 return lttng_add_cgroup_ns_to_ctx(ctx);
1548         case LTTNG_UST_CONTEXT_IPC_NS:
1549                 return lttng_add_ipc_ns_to_ctx(ctx);
1550         case LTTNG_UST_CONTEXT_MNT_NS:
1551                 return lttng_add_mnt_ns_to_ctx(ctx);
1552         case LTTNG_UST_CONTEXT_NET_NS:
1553                 return lttng_add_net_ns_to_ctx(ctx);
1554         case LTTNG_UST_CONTEXT_PID_NS:
1555                 return lttng_add_pid_ns_to_ctx(ctx);
1556         case LTTNG_UST_CONTEXT_TIME_NS:
1557                 return lttng_add_time_ns_to_ctx(ctx);
1558         case LTTNG_UST_CONTEXT_USER_NS:
1559                 return lttng_add_user_ns_to_ctx(ctx);
1560         case LTTNG_UST_CONTEXT_UTS_NS:
1561                 return lttng_add_uts_ns_to_ctx(ctx);
1562         case LTTNG_UST_CONTEXT_VUID:
1563                 return lttng_add_vuid_to_ctx(ctx);
1564         case LTTNG_UST_CONTEXT_VEUID:
1565                 return lttng_add_veuid_to_ctx(ctx);
1566         case LTTNG_UST_CONTEXT_VSUID:
1567                 return lttng_add_vsuid_to_ctx(ctx);
1568         case LTTNG_UST_CONTEXT_VGID:
1569                 return lttng_add_vgid_to_ctx(ctx);
1570         case LTTNG_UST_CONTEXT_VEGID:
1571                 return lttng_add_vegid_to_ctx(ctx);
1572         case LTTNG_UST_CONTEXT_VSGID:
1573                 return lttng_add_vsgid_to_ctx(ctx);
1574         default:
1575                 return -EINVAL;
1576         }
1577 }
1578
1579 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1580                 struct lttng_ust_context *context_param)
1581 {
1582         return -ENOSYS;
1583 }
1584
1585 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1586 {
1587         if (!event_enabler) {
1588                 return;
1589         }
1590         cds_list_del(&event_enabler->node);
1591
1592         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1593
1594         lttng_destroy_context(event_enabler->ctx);
1595         free(event_enabler);
1596 }
1597
1598 /*
1599  * lttng_session_sync_event_enablers should be called just before starting a
1600  * session.
1601  */
1602 static
1603 void lttng_session_sync_event_enablers(struct lttng_session *session)
1604 {
1605         struct lttng_event_enabler *event_enabler;
1606         struct lttng_event *event;
1607
1608         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1609                 lttng_event_enabler_ref_events(event_enabler);
1610         /*
1611          * For each event, if at least one of its enablers is enabled,
1612          * and its channel and session transient states are enabled, we
1613          * enable the event, else we disable it.
1614          */
1615         cds_list_for_each_entry(event, &session->events_head, node) {
1616                 struct lttng_enabler_ref *enabler_ref;
1617                 struct lttng_bytecode_runtime *runtime;
1618                 int enabled = 0, has_enablers_without_bytecode = 0;
1619
1620                 /* Enable events */
1621                 cds_list_for_each_entry(enabler_ref,
1622                                 &event->enablers_ref_head, node) {
1623                         if (enabler_ref->ref->enabled) {
1624                                 enabled = 1;
1625                                 break;
1626                         }
1627                 }
1628                 /*
1629                  * Enabled state is based on union of enablers, with
1630                  * intesection of session and channel transient enable
1631                  * states.
1632                  */
1633                 enabled = enabled && session->tstate && event->chan->tstate;
1634
1635                 CMM_STORE_SHARED(event->enabled, enabled);
1636                 /*
1637                  * Sync tracepoint registration with event enabled
1638                  * state.
1639                  */
1640                 if (enabled) {
1641                         if (!event->registered)
1642                                 register_event(event);
1643                 } else {
1644                         if (event->registered)
1645                                 unregister_event(event);
1646                 }
1647
1648                 /* Check if has enablers without bytecode enabled */
1649                 cds_list_for_each_entry(enabler_ref,
1650                                 &event->enablers_ref_head, node) {
1651                         if (enabler_ref->ref->enabled
1652                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1653                                 has_enablers_without_bytecode = 1;
1654                                 break;
1655                         }
1656                 }
1657                 event->has_enablers_without_bytecode =
1658                         has_enablers_without_bytecode;
1659
1660                 /* Enable filters */
1661                 cds_list_for_each_entry(runtime,
1662                                 &event->filter_bytecode_runtime_head, node) {
1663                         lttng_bytecode_filter_sync_state(runtime);
1664                 }
1665         }
1666         __tracepoint_probe_prune_release_queue();
1667 }
1668
1669 static
1670 void lttng_create_event_notifier_if_missing(
1671                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1672 {
1673         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1674         struct lttng_probe_desc *probe_desc;
1675         struct cds_list_head *probe_list;
1676         int i;
1677
1678         probe_list = lttng_get_probe_list_head();
1679
1680         cds_list_for_each_entry(probe_desc, probe_list, head) {
1681                 for (i = 0; i < probe_desc->nr_events; i++) {
1682                         int ret;
1683                         bool found = false;
1684                         const struct lttng_event_desc *desc;
1685                         struct lttng_event_notifier *event_notifier;
1686                         struct cds_hlist_head *head;
1687                         struct cds_hlist_node *node;
1688
1689                         desc = probe_desc->event_desc[i];
1690
1691                         if (!lttng_desc_match_enabler(desc,
1692                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1693                                 continue;
1694
1695                         /*
1696                          * Given the current event_notifier group, get the bucket that
1697                          * the target event_notifier would be if it was already
1698                          * created.
1699                          */
1700                         head = borrow_hash_table_bucket(
1701                                 event_notifier_group->event_notifiers_ht.table,
1702                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1703
1704                         cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
1705                                 /*
1706                                  * Check if event_notifier already exists by checking
1707                                  * if the event_notifier and enabler share the same
1708                                  * description and id.
1709                                  */
1710                                 if (event_notifier->desc == desc &&
1711                                                 event_notifier->user_token == event_notifier_enabler->user_token) {
1712                                         found = true;
1713                                         break;
1714                                 }
1715                         }
1716
1717                         if (found)
1718                                 continue;
1719
1720                         /*
1721                          * We need to create a event_notifier for this event probe.
1722                          */
1723                         ret = lttng_event_notifier_create(desc,
1724                                 event_notifier_enabler->user_token,
1725                                 event_notifier_group);
1726                         if (ret) {
1727                                 DBG("Unable to create event_notifier %s, error %d\n",
1728                                         probe_desc->event_desc[i]->name, ret);
1729                         }
1730                 }
1731         }
1732 }
1733
1734 /*
1735  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1736  */
1737 static
1738 int lttng_event_notifier_enabler_ref_event_notifiers(
1739                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1740 {
1741         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1742         struct lttng_event_notifier *event_notifier;
1743
1744          /*
1745           * Only try to create event_notifiers for enablers that are enabled, the user
1746           * might still be attaching filter or exclusion to the
1747           * event_notifier_enabler.
1748           */
1749         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1750                 goto end;
1751
1752         /* First, ensure that probe event_notifiers are created for this enabler. */
1753         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1754
1755         /* Link the created event_notifier with its associated enabler. */
1756         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1757                 struct lttng_enabler_ref *enabler_ref;
1758
1759                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
1760                         continue;
1761
1762                 enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
1763                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1764                 if (!enabler_ref) {
1765                         /*
1766                          * If no backward ref, create it.
1767                          * Add backward ref from event_notifier to enabler.
1768                          */
1769                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1770                         if (!enabler_ref)
1771                                 return -ENOMEM;
1772
1773                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1774                                 event_notifier_enabler);
1775                         cds_list_add(&enabler_ref->node,
1776                                 &event_notifier->enablers_ref_head);
1777                 }
1778
1779                 /*
1780                  * Link filter bytecodes if not linked yet.
1781                  */
1782                 lttng_enabler_link_bytecode(event_notifier->desc,
1783                         &event_notifier_group->ctx,
1784                         &event_notifier->filter_bytecode_runtime_head,
1785                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1786
1787                 /*
1788                  * Link capture bytecodes if not linked yet.
1789                  */
1790                 lttng_enabler_link_bytecode(event_notifier->desc,
1791                         &event_notifier_group->ctx, &event_notifier->capture_bytecode_runtime_head,
1792                         &event_notifier_enabler->capture_bytecode_head);
1793
1794                 event_notifier->num_captures = event_notifier_enabler->num_captures;
1795         }
1796 end:
1797         return 0;
1798 }
1799
1800 static
1801 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1802 {
1803         struct lttng_event_notifier_enabler *event_notifier_enabler;
1804         struct lttng_event_notifier *event_notifier;
1805
1806         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1807                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1808
1809         /*
1810          * For each event_notifier, if at least one of its enablers is enabled,
1811          * we enable the event_notifier, else we disable it.
1812          */
1813         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1814                 struct lttng_enabler_ref *enabler_ref;
1815                 struct lttng_bytecode_runtime *runtime;
1816                 int enabled = 0, has_enablers_without_bytecode = 0;
1817
1818                 /* Enable event_notifiers */
1819                 cds_list_for_each_entry(enabler_ref,
1820                                 &event_notifier->enablers_ref_head, node) {
1821                         if (enabler_ref->ref->enabled) {
1822                                 enabled = 1;
1823                                 break;
1824                         }
1825                 }
1826
1827                 CMM_STORE_SHARED(event_notifier->enabled, enabled);
1828                 /*
1829                  * Sync tracepoint registration with event_notifier enabled
1830                  * state.
1831                  */
1832                 if (enabled) {
1833                         if (!event_notifier->registered)
1834                                 register_event_notifier(event_notifier);
1835                 } else {
1836                         if (event_notifier->registered)
1837                                 unregister_event_notifier(event_notifier);
1838                 }
1839
1840                 /* Check if has enablers without bytecode enabled */
1841                 cds_list_for_each_entry(enabler_ref,
1842                                 &event_notifier->enablers_ref_head, node) {
1843                         if (enabler_ref->ref->enabled
1844                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1845                                 has_enablers_without_bytecode = 1;
1846                                 break;
1847                         }
1848                 }
1849                 event_notifier->has_enablers_without_bytecode =
1850                         has_enablers_without_bytecode;
1851
1852                 /* Enable filters */
1853                 cds_list_for_each_entry(runtime,
1854                                 &event_notifier->filter_bytecode_runtime_head, node) {
1855                         lttng_bytecode_filter_sync_state(runtime);
1856                 }
1857
1858                 /* Enable captures. */
1859                 cds_list_for_each_entry(runtime,
1860                                 &event_notifier->capture_bytecode_runtime_head, node) {
1861                         lttng_bytecode_capture_sync_state(runtime);
1862                 }
1863         }
1864         __tracepoint_probe_prune_release_queue();
1865 }
1866
1867 /*
1868  * Apply enablers to session events, adding events to session if need
1869  * be. It is required after each modification applied to an active
1870  * session, and right before session "start".
1871  * "lazy" sync means we only sync if required.
1872  */
1873 static
1874 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1875 {
1876         /* We can skip if session is not active */
1877         if (!session->active)
1878                 return;
1879         lttng_session_sync_event_enablers(session);
1880 }
1881
1882 /*
1883  * Update all sessions with the given app context.
1884  * Called with ust lock held.
1885  * This is invoked when an application context gets loaded/unloaded. It
1886  * ensures the context callbacks are in sync with the application
1887  * context (either app context callbacks, or dummy callbacks).
1888  */
1889 void lttng_ust_context_set_session_provider(const char *name,
1890                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1891                 void (*record)(struct lttng_ctx_field *field,
1892                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1893                         struct lttng_channel *chan),
1894                 void (*get_value)(struct lttng_ctx_field *field,
1895                         struct lttng_ctx_value *value))
1896 {
1897         struct lttng_session *session;
1898
1899         cds_list_for_each_entry(session, &sessions, node) {
1900                 struct lttng_channel *chan;
1901                 struct lttng_event *event;
1902                 int ret;
1903
1904                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1905                                 name, get_size, record, get_value);
1906                 if (ret)
1907                         abort();
1908                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1909                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1910                                         name, get_size, record, get_value);
1911                         if (ret)
1912                                 abort();
1913                 }
1914                 cds_list_for_each_entry(event, &session->events_head, node) {
1915                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1916                                         name, get_size, record, get_value);
1917                         if (ret)
1918                                 abort();
1919                 }
1920         }
1921 }
1922
1923 /*
1924  * Update all event_notifier groups with the given app context.
1925  * Called with ust lock held.
1926  * This is invoked when an application context gets loaded/unloaded. It
1927  * ensures the context callbacks are in sync with the application
1928  * context (either app context callbacks, or dummy callbacks).
1929  */
1930 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
1931                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1932                 void (*record)(struct lttng_ctx_field *field,
1933                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1934                         struct lttng_channel *chan),
1935                 void (*get_value)(struct lttng_ctx_field *field,
1936                         struct lttng_ctx_value *value))
1937 {
1938         struct lttng_event_notifier_group *event_notifier_group;
1939
1940         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1941                 int ret;
1942
1943                 ret = lttng_ust_context_set_provider_rcu(
1944                                 &event_notifier_group->ctx,
1945                                 name, get_size, record, get_value);
1946                 if (ret)
1947                         abort();
1948         }
1949 }