liblttng-ust/lttng-events.c

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Holds LTTng per-session event registry.
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <stdio.h>
  11 #include <assert.h>
  12 #include <errno.h>
  13 #include <limits.h>
  14 #include <pthread.h>
  15 #include <sys/shm.h>
  16 #include <sys/ipc.h>
  17 #include <stdint.h>
  18 #include <stddef.h>
  19 #include <inttypes.h>
  20 #include <time.h>
  21 #include <stdbool.h>
  22 #include <unistd.h>
  23 #include <dlfcn.h>
  24 #include <lttng/ust-endian.h>
  25
  26 #include <urcu/arch.h>
  27 #include <urcu/compiler.h>
  28 #include <urcu/hlist.h>
  29 #include <urcu/list.h>
  30 #include <urcu/uatomic.h>
  31
  32 #include <lttng/tracepoint.h>
  33 #include <lttng/ust-events.h>
  34
  35 #include <usterr-signal-safe.h>
  36 #include <ust-helper.h>
  37 #include <lttng/ust-ctl.h>
  38 #include <ust-comm.h>
  39 #include <ust-fd.h>
  40 #include <ust-dynamic-type.h>
  41 #include <ust-context-provider.h>
  42 #include "error.h"
  43 #include "compat.h"
  44 #include "lttng-ust-uuid.h"
  45
  46 #include "tracepoint-internal.h"
  47 #include "string-utils.h"
  48 #include "lttng-bytecode.h"
  49 #include "lttng-tracer.h"
  50 #include "lttng-tracer-core.h"
  51 #include "lttng-ust-statedump.h"
  52 #include "context-internal.h"
  53 #include "ust-events-internal.h"
  54 #include "wait.h"
  55 #include "../libringbuffer/shm.h"
  56 #include "../libcounter/counter.h"
  57 #include "jhash.h"
  58 #include <lttng/ust-abi.h>
  59
  60 /*
  61  * All operations within this file are called by the communication
  62  * thread, under ust_lock protection.
  63  */
  64
  65 static CDS_LIST_HEAD(sessions);
  66 static CDS_LIST_HEAD(event_notifier_groups);
  67
  68 struct cds_list_head *_lttng_get_sessions(void)
  69 {
  70         return &sessions;
  71 }
  72
  73 static void _lttng_event_destroy(struct lttng_event *event);
  74 static void _lttng_event_notifier_destroy(
  75                 struct lttng_event_notifier *event_notifier);
  76 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  77
  78 static
  79 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  80 static
  81 void lttng_session_sync_event_enablers(struct lttng_session *session);
  82 static
  83 void lttng_event_notifier_group_sync_enablers(
  84                 struct lttng_event_notifier_group *event_notifier_group);
  85 static
  86 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  87
  88 /*
  89  * Called with ust lock held.
  90  */
  91 int lttng_session_active(void)
  92 {
  93         struct lttng_session *iter;
  94
  95         cds_list_for_each_entry(iter, &sessions, node) {
  96                 if (iter->active)
  97                         return 1;
  98         }
  99         return 0;
 100 }
 101
 102 static
 103 int lttng_loglevel_match(int loglevel,
 104                 unsigned int has_loglevel,
 105                 enum lttng_ust_loglevel_type req_type,
 106                 int req_loglevel)
 107 {
 108         if (!has_loglevel)
 109                 loglevel = TRACE_DEFAULT;
 110         switch (req_type) {
 111         case LTTNG_UST_LOGLEVEL_RANGE:
 112                 if (loglevel <= req_loglevel
 113                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 114                         return 1;
 115                 else
 116                         return 0;
 117         case LTTNG_UST_LOGLEVEL_SINGLE:
 118                 if (loglevel == req_loglevel
 119                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 120                         return 1;
 121                 else
 122                         return 0;
 123         case LTTNG_UST_LOGLEVEL_ALL:
 124         default:
 125                 if (loglevel <= TRACE_DEBUG)
 126                         return 1;
 127                 else
 128                         return 0;
 129         }
 130 }
 131
 132 struct lttng_session *lttng_session_create(void)
 133 {
 134         struct lttng_session *session;
 135         int i;
 136
 137         session = zmalloc(sizeof(struct lttng_session));
 138         if (!session)
 139                 return NULL;
 140         if (lttng_context_init_all(&session->ctx)) {
 141                 free(session);
 142                 return NULL;
 143         }
 144         CDS_INIT_LIST_HEAD(&session->chan_head);
 145         CDS_INIT_LIST_HEAD(&session->events_head);
 146         CDS_INIT_LIST_HEAD(&session->enums_head);
 147         CDS_INIT_LIST_HEAD(&session->enablers_head);
 148         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 149                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 150         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 151                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 152         cds_list_add(&session->node, &sessions);
 153         return session;
 154 }
 155
 156 struct lttng_counter *lttng_ust_counter_create(
 157                 const char *counter_transport_name,
 158                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 159 {
 160         struct lttng_counter_transport *counter_transport = NULL;
 161         struct lttng_counter *counter = NULL;
 162
 163         counter_transport = lttng_counter_transport_find(counter_transport_name);
 164         if (!counter_transport)
 165                 goto notransport;
 166         counter = zmalloc(sizeof(struct lttng_counter));
 167         if (!counter)
 168                 goto nomem;
 169
 170         counter->ops = &counter_transport->ops;
 171         counter->transport = counter_transport;
 172
 173         counter->counter = counter->ops->counter_create(
 174                         number_dimensions, dimensions, 0,
 175                         -1, 0, NULL, false);
 176         if (!counter->counter) {
 177                 goto create_error;
 178         }
 179
 180         return counter;
 181
 182 create_error:
 183         free(counter);
 184 nomem:
 185 notransport:
 186         return NULL;
 187 }
 188
 189 static
 190 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 191 {
 192         counter->ops->counter_destroy(counter->counter);
 193         free(counter);
 194 }
 195
 196 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 197 {
 198         struct lttng_event_notifier_group *event_notifier_group;
 199         int i;
 200
 201         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 202         if (!event_notifier_group)
 203                 return NULL;
 204
 205         /* Add all contexts. */
 206         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 207                 free(event_notifier_group);
 208                 return NULL;
 209         }
 210
 211         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 212         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 213         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 214                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 215
 216         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 217
 218         return event_notifier_group;
 219 }
 220
 221 /*
 222  * Only used internally at session destruction.
 223  */
 224 static
 225 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 226 {
 227         struct channel *chan;
 228         struct lttng_ust_shm_handle *handle;
 229
 230         cds_list_del(&lttng_chan->node);
 231         lttng_destroy_context(lttng_chan->ctx);
 232         chan = lttng_chan->chan;
 233         handle = lttng_chan->handle;
 234         /*
 235          * note: lttng_chan is private data contained within handle. It
 236          * will be freed along with the handle.
 237          */
 238         channel_destroy(chan, handle, 0);
 239 }
 240
 241 static
 242 void register_event(struct lttng_event *event)
 243 {
 244         int ret;
 245         const struct lttng_event_desc *desc;
 246
 247         assert(event->registered == 0);
 248         desc = event->desc;
 249         ret = __tracepoint_probe_register_queue_release(desc->name,
 250                         desc->probe_callback,
 251                         event, desc->signature);
 252         WARN_ON_ONCE(ret);
 253         if (!ret)
 254                 event->registered = 1;
 255 }
 256
 257 static
 258 void register_event_notifier(struct lttng_event_notifier *event_notifier)
 259 {
 260         int ret;
 261         const struct lttng_event_desc *desc;
 262
 263         assert(event_notifier->registered == 0);
 264         desc = event_notifier->desc;
 265         ret = __tracepoint_probe_register_queue_release(desc->name,
 266                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 267         WARN_ON_ONCE(ret);
 268         if (!ret)
 269                 event_notifier->registered = 1;
 270 }
 271
 272 static
 273 void unregister_event(struct lttng_event *event)
 274 {
 275         int ret;
 276         const struct lttng_event_desc *desc;
 277
 278         assert(event->registered == 1);
 279         desc = event->desc;
 280         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 281                         desc->probe_callback,
 282                         event);
 283         WARN_ON_ONCE(ret);
 284         if (!ret)
 285                 event->registered = 0;
 286 }
 287
 288 static
 289 void unregister_event_notifier(struct lttng_event_notifier *event_notifier)
 290 {
 291         int ret;
 292         const struct lttng_event_desc *desc;
 293
 294         assert(event_notifier->registered == 1);
 295         desc = event_notifier->desc;
 296         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 297                 desc->u.ext.event_notifier_callback, event_notifier);
 298         WARN_ON_ONCE(ret);
 299         if (!ret)
 300                 event_notifier->registered = 0;
 301 }
 302
 303 /*
 304  * Only used internally at session destruction.
 305  */
 306 static
 307 void _lttng_event_unregister(struct lttng_event *event)
 308 {
 309         if (event->registered)
 310                 unregister_event(event);
 311 }
 312
 313 /*
 314  * Only used internally at session destruction.
 315  */
 316 static
 317 void _lttng_event_notifier_unregister(struct lttng_event_notifier *event_notifier)
 318 {
 319         if (event_notifier->registered)
 320                 unregister_event_notifier(event_notifier);
 321 }
 322
 323 void lttng_session_destroy(struct lttng_session *session)
 324 {
 325         struct lttng_channel *chan, *tmpchan;
 326         struct lttng_event *event, *tmpevent;
 327         struct lttng_enum *_enum, *tmp_enum;
 328         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 329
 330         CMM_ACCESS_ONCE(session->active) = 0;
 331         cds_list_for_each_entry(event, &session->events_head, node) {
 332                 _lttng_event_unregister(event);
 333         }
 334         lttng_ust_synchronize_trace();  /* Wait for in-flight events to complete */
 335         __tracepoint_probe_prune_release_queue();
 336         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 337                         &session->enablers_head, node)
 338                 lttng_event_enabler_destroy(event_enabler);
 339         cds_list_for_each_entry_safe(event, tmpevent,
 340                         &session->events_head, node)
 341                 _lttng_event_destroy(event);
 342         cds_list_for_each_entry_safe(_enum, tmp_enum,
 343                         &session->enums_head, node)
 344                 _lttng_enum_destroy(_enum);
 345         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 346                 _lttng_channel_unmap(chan);
 347         cds_list_del(&session->node);
 348         lttng_destroy_context(session->ctx);
 349         free(session);
 350 }
 351
 352 void lttng_event_notifier_group_destroy(
 353                 struct lttng_event_notifier_group *event_notifier_group)
 354 {
 355         int close_ret;
 356         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 357         struct lttng_event_notifier *notifier, *tmpnotifier;
 358
 359         if (!event_notifier_group) {
 360                 return;
 361         }
 362
 363         cds_list_for_each_entry(notifier,
 364                         &event_notifier_group->event_notifiers_head, node)
 365                 _lttng_event_notifier_unregister(notifier);
 366
 367         lttng_ust_synchronize_trace();
 368
 369         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 370                         &event_notifier_group->enablers_head, node)
 371                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 372
 373         cds_list_for_each_entry_safe(notifier, tmpnotifier,
 374                         &event_notifier_group->event_notifiers_head, node)
 375                 _lttng_event_notifier_destroy(notifier);
 376
 377         if (event_notifier_group->error_counter)
 378                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 379
 380         /* Close the notification fd to the listener of event_notifiers. */
 381
 382         lttng_ust_lock_fd_tracker();
 383         close_ret = close(event_notifier_group->notification_fd);
 384         if (!close_ret) {
 385                 lttng_ust_delete_fd_from_tracker(
 386                                 event_notifier_group->notification_fd);
 387         } else {
 388                 PERROR("close");
 389                 abort();
 390         }
 391         lttng_ust_unlock_fd_tracker();
 392
 393         cds_list_del(&event_notifier_group->node);
 394
 395         free(event_notifier_group);
 396 }
 397
 398 static
 399 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 400 {
 401         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 402         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 403
 404         if (!enabler) {
 405                 return;
 406         }
 407
 408         /* Destroy filter bytecode */
 409         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 410                         &enabler->filter_bytecode_head, node) {
 411                 free(filter_node);
 412         }
 413
 414         /* Destroy excluders */
 415         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 416                         &enabler->excluder_head, node) {
 417                 free(excluder_node);
 418         }
 419 }
 420
 421  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 422 {
 423         if (!event_notifier_enabler) {
 424                 return;
 425         }
 426
 427         cds_list_del(&event_notifier_enabler->node);
 428
 429         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 430
 431         free(event_notifier_enabler);
 432 }
 433
 434 static
 435 int lttng_enum_create(const struct lttng_enum_desc *desc,
 436                 struct lttng_session *session)
 437 {
 438         const char *enum_name = desc->name;
 439         struct lttng_enum *_enum;
 440         struct cds_hlist_head *head;
 441         int ret = 0;
 442         size_t name_len = strlen(enum_name);
 443         uint32_t hash;
 444         int notify_socket;
 445
 446         /* Check if this enum is already registered for this session. */
 447         hash = jhash(enum_name, name_len, 0);
 448         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 449
 450         _enum = lttng_ust_enum_get_from_desc(session, desc);
 451         if (_enum) {
 452                 ret = -EEXIST;
 453                 goto exist;
 454         }
 455
 456         notify_socket = lttng_get_notify_socket(session->owner);
 457         if (notify_socket < 0) {
 458                 ret = notify_socket;
 459                 goto socket_error;
 460         }
 461
 462         _enum = zmalloc(sizeof(*_enum));
 463         if (!_enum) {
 464                 ret = -ENOMEM;
 465                 goto cache_error;
 466         }
 467         _enum->session = session;
 468         _enum->desc = desc;
 469
 470         ret = ustcomm_register_enum(notify_socket,
 471                 session->objd,
 472                 enum_name,
 473                 desc->nr_entries,
 474                 desc->entries,
 475                 &_enum->id);
 476         if (ret < 0) {
 477                 DBG("Error (%d) registering enumeration to sessiond", ret);
 478                 goto sessiond_register_error;
 479         }
 480         cds_list_add(&_enum->node, &session->enums_head);
 481         cds_hlist_add_head(&_enum->hlist, head);
 482         return 0;
 483
 484 sessiond_register_error:
 485         free(_enum);
 486 cache_error:
 487 socket_error:
 488 exist:
 489         return ret;
 490 }
 491
 492 static
 493 int lttng_create_enum_check(const struct lttng_type *type,
 494                 struct lttng_session *session)
 495 {
 496         switch (type->atype) {
 497         case atype_enum:
 498         {
 499                 const struct lttng_enum_desc *enum_desc;
 500                 int ret;
 501
 502                 enum_desc = type->u.legacy.basic.enumeration.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         case atype_enum_nestable:
 511         {
 512                 const struct lttng_enum_desc *enum_desc;
 513                 int ret;
 514
 515                 enum_desc = type->u.enum_nestable.desc;
 516                 ret = lttng_enum_create(enum_desc, session);
 517                 if (ret && ret != -EEXIST) {
 518                         DBG("Unable to create enum error: (%d)", ret);
 519                         return ret;
 520                 }
 521                 break;
 522         }
 523         case atype_dynamic:
 524         {
 525                 const struct lttng_event_field *tag_field_generic;
 526                 const struct lttng_enum_desc *enum_desc;
 527                 int ret;
 528
 529                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 530                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 531                 ret = lttng_enum_create(enum_desc, session);
 532                 if (ret && ret != -EEXIST) {
 533                         DBG("Unable to create enum error: (%d)", ret);
 534                         return ret;
 535                 }
 536                 break;
 537         }
 538         default:
 539                 /* TODO: nested types when they become supported. */
 540                 break;
 541         }
 542         return 0;
 543 }
 544
 545 static
 546 int lttng_create_all_event_enums(size_t nr_fields,
 547                 const struct lttng_event_field *event_fields,
 548                 struct lttng_session *session)
 549 {
 550         size_t i;
 551         int ret;
 552
 553         /* For each field, ensure enum is part of the session. */
 554         for (i = 0; i < nr_fields; i++) {
 555                 const struct lttng_type *type = &event_fields[i].type;
 556
 557                 ret = lttng_create_enum_check(type, session);
 558                 if (ret)
 559                         return ret;
 560         }
 561         return 0;
 562 }
 563
 564 static
 565 int lttng_create_all_ctx_enums(size_t nr_fields,
 566                 const struct lttng_ctx_field *ctx_fields,
 567                 struct lttng_session *session)
 568 {
 569         size_t i;
 570         int ret;
 571
 572         /* For each field, ensure enum is part of the session. */
 573         for (i = 0; i < nr_fields; i++) {
 574                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 575
 576                 ret = lttng_create_enum_check(type, session);
 577                 if (ret)
 578                         return ret;
 579         }
 580         return 0;
 581 }
 582
 583 /*
 584  * Ensure that a state-dump will be performed for this session at the end
 585  * of the current handle_message().
 586  */
 587 int lttng_session_statedump(struct lttng_session *session)
 588 {
 589         session->statedump_pending = 1;
 590         lttng_ust_sockinfo_session_enabled(session->owner);
 591         return 0;
 592 }
 593
 594 int lttng_session_enable(struct lttng_session *session)
 595 {
 596         int ret = 0;
 597         struct lttng_channel *chan;
 598         int notify_socket;
 599
 600         if (session->active) {
 601                 ret = -EBUSY;
 602                 goto end;
 603         }
 604
 605         notify_socket = lttng_get_notify_socket(session->owner);
 606         if (notify_socket < 0)
 607                 return notify_socket;
 608
 609         /* Set transient enabler state to "enabled" */
 610         session->tstate = 1;
 611
 612         /* We need to sync enablers with session before activation. */
 613         lttng_session_sync_event_enablers(session);
 614
 615         /*
 616          * Snapshot the number of events per channel to know the type of header
 617          * we need to use.
 618          */
 619         cds_list_for_each_entry(chan, &session->chan_head, node) {
 620                 const struct lttng_ctx *ctx;
 621                 const struct lttng_ctx_field *fields = NULL;
 622                 size_t nr_fields = 0;
 623                 uint32_t chan_id;
 624
 625                 /* don't change it if session stop/restart */
 626                 if (chan->header_type)
 627                         continue;
 628                 ctx = chan->ctx;
 629                 if (ctx) {
 630                         nr_fields = ctx->nr_fields;
 631                         fields = ctx->fields;
 632                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 633                                 session);
 634                         if (ret < 0) {
 635                                 DBG("Error (%d) adding enum to session", ret);
 636                                 return ret;
 637                         }
 638                 }
 639                 ret = ustcomm_register_channel(notify_socket,
 640                         session,
 641                         session->objd,
 642                         chan->objd,
 643                         nr_fields,
 644                         fields,
 645                         &chan_id,
 646                         &chan->header_type);
 647                 if (ret) {
 648                         DBG("Error (%d) registering channel to sessiond", ret);
 649                         return ret;
 650                 }
 651                 if (chan_id != chan->id) {
 652                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 653                                 chan_id, chan->id);
 654                         return -EINVAL;
 655                 }
 656         }
 657
 658         /* Set atomically the state to "active" */
 659         CMM_ACCESS_ONCE(session->active) = 1;
 660         CMM_ACCESS_ONCE(session->been_active) = 1;
 661
 662         ret = lttng_session_statedump(session);
 663         if (ret)
 664                 return ret;
 665 end:
 666         return ret;
 667 }
 668
 669 int lttng_session_disable(struct lttng_session *session)
 670 {
 671         int ret = 0;
 672
 673         if (!session->active) {
 674                 ret = -EBUSY;
 675                 goto end;
 676         }
 677         /* Set atomically the state to "inactive" */
 678         CMM_ACCESS_ONCE(session->active) = 0;
 679
 680         /* Set transient enabler state to "disabled" */
 681         session->tstate = 0;
 682         lttng_session_sync_event_enablers(session);
 683 end:
 684         return ret;
 685 }
 686
 687 int lttng_channel_enable(struct lttng_channel *channel)
 688 {
 689         int ret = 0;
 690
 691         if (channel->enabled) {
 692                 ret = -EBUSY;
 693                 goto end;
 694         }
 695         /* Set transient enabler state to "enabled" */
 696         channel->tstate = 1;
 697         lttng_session_sync_event_enablers(channel->session);
 698         /* Set atomically the state to "enabled" */
 699         CMM_ACCESS_ONCE(channel->enabled) = 1;
 700 end:
 701         return ret;
 702 }
 703
 704 int lttng_channel_disable(struct lttng_channel *channel)
 705 {
 706         int ret = 0;
 707
 708         if (!channel->enabled) {
 709                 ret = -EBUSY;
 710                 goto end;
 711         }
 712         /* Set atomically the state to "disabled" */
 713         CMM_ACCESS_ONCE(channel->enabled) = 0;
 714         /* Set transient enabler state to "enabled" */
 715         channel->tstate = 0;
 716         lttng_session_sync_event_enablers(channel->session);
 717 end:
 718         return ret;
 719 }
 720
 721 static inline
 722 struct cds_hlist_head *borrow_hash_table_bucket(
 723                 struct cds_hlist_head *hash_table,
 724                 unsigned int hash_table_size,
 725                 const struct lttng_event_desc *desc)
 726 {
 727         const char *event_name;
 728         size_t name_len;
 729         uint32_t hash;
 730
 731         event_name = desc->name;
 732         name_len = strlen(event_name);
 733
 734         hash = jhash(event_name, name_len, 0);
 735         return &hash_table[hash & (hash_table_size - 1)];
 736 }
 737
 738 /*
 739  * Supports event creation while tracing session is active.
 740  */
 741 static
 742 int lttng_event_create(const struct lttng_event_desc *desc,
 743                 struct lttng_channel *chan)
 744 {
 745         struct lttng_event *event;
 746         struct lttng_session *session = chan->session;
 747         struct cds_hlist_head *head;
 748         int ret = 0;
 749         int notify_socket, loglevel;
 750         const char *uri;
 751
 752         head = borrow_hash_table_bucket(chan->session->events_ht.table,
 753                 LTTNG_UST_EVENT_HT_SIZE, desc);
 754
 755         notify_socket = lttng_get_notify_socket(session->owner);
 756         if (notify_socket < 0) {
 757                 ret = notify_socket;
 758                 goto socket_error;
 759         }
 760
 761         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 762                         session);
 763         if (ret < 0) {
 764                 DBG("Error (%d) adding enum to session", ret);
 765                 goto create_enum_error;
 766         }
 767
 768         /*
 769          * Check if loglevel match. Refuse to connect event if not.
 770          */
 771         event = zmalloc(sizeof(struct lttng_event));
 772         if (!event) {
 773                 ret = -ENOMEM;
 774                 goto cache_error;
 775         }
 776         event->chan = chan;
 777
 778         /* Event will be enabled by enabler sync. */
 779         event->enabled = 0;
 780         event->registered = 0;
 781         CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
 782         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 783         event->desc = desc;
 784
 785         if (desc->loglevel)
 786                 loglevel = *(*event->desc->loglevel);
 787         else
 788                 loglevel = TRACE_DEFAULT;
 789         if (desc->u.ext.model_emf_uri)
 790                 uri = *(desc->u.ext.model_emf_uri);
 791         else
 792                 uri = NULL;
 793
 794         /* Fetch event ID from sessiond */
 795         ret = ustcomm_register_event(notify_socket,
 796                 session,
 797                 session->objd,
 798                 chan->objd,
 799                 desc->name,
 800                 loglevel,
 801                 desc->signature,
 802                 desc->nr_fields,
 803                 desc->fields,
 804                 uri,
 805                 &event->id);
 806         if (ret < 0) {
 807                 DBG("Error (%d) registering event to sessiond", ret);
 808                 goto sessiond_register_error;
 809         }
 810
 811         cds_list_add(&event->node, &chan->session->events_head);
 812         cds_hlist_add_head(&event->hlist, head);
 813         return 0;
 814
 815 sessiond_register_error:
 816         free(event);
 817 cache_error:
 818 create_enum_error:
 819 socket_error:
 820         return ret;
 821 }
 822
 823 static
 824 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 825                 uint64_t token, uint64_t error_counter_index,
 826                 struct lttng_event_notifier_group *event_notifier_group)
 827 {
 828         struct lttng_event_notifier *event_notifier;
 829         struct cds_hlist_head *head;
 830         int ret = 0;
 831
 832         /*
 833          * Get the hashtable bucket the created lttng_event_notifier object
 834          * should be inserted.
 835          */
 836         head = borrow_hash_table_bucket(
 837                 event_notifier_group->event_notifiers_ht.table,
 838                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 839
 840         event_notifier = zmalloc(sizeof(struct lttng_event_notifier));
 841         if (!event_notifier) {
 842                 ret = -ENOMEM;
 843                 goto error;
 844         }
 845
 846         event_notifier->group = event_notifier_group;
 847         event_notifier->user_token = token;
 848         event_notifier->error_counter_index = error_counter_index;
 849
 850         /* Event notifier will be enabled by enabler sync. */
 851         event_notifier->enabled = 0;
 852         event_notifier->registered = 0;
 853
 854         CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
 855         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 856         CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
 857         event_notifier->desc = desc;
 858         event_notifier->notification_send = lttng_event_notifier_notification_send;
 859
 860         cds_list_add(&event_notifier->node,
 861                         &event_notifier_group->event_notifiers_head);
 862         cds_hlist_add_head(&event_notifier->hlist, head);
 863
 864         return 0;
 865
 866 error:
 867         return ret;
 868 }
 869
 870 static
 871 void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
 872 {
 873         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 874
 875         /* Remove from event_notifier list. */
 876         cds_list_del(&event_notifier->node);
 877         /* Remove from event_notifier hash table. */
 878         cds_hlist_del(&event_notifier->hlist);
 879
 880         lttng_free_event_notifier_filter_runtime(event_notifier);
 881
 882         /* Free event_notifier enabler refs */
 883         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 884                         &event_notifier->enablers_ref_head, node)
 885                 free(enabler_ref);
 886         free(event_notifier);
 887 }
 888
 889 static
 890 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 891                 struct lttng_enabler *enabler)
 892 {
 893         int loglevel = 0;
 894         unsigned int has_loglevel = 0;
 895
 896         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 897         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 898                         desc->name, SIZE_MAX))
 899                 return 0;
 900         if (desc->loglevel) {
 901                 loglevel = *(*desc->loglevel);
 902                 has_loglevel = 1;
 903         }
 904         if (!lttng_loglevel_match(loglevel,
 905                         has_loglevel,
 906                         enabler->event_param.loglevel_type,
 907                         enabler->event_param.loglevel))
 908                 return 0;
 909         return 1;
 910 }
 911
 912 static
 913 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 914                 struct lttng_enabler *enabler)
 915 {
 916         int loglevel = 0;
 917         unsigned int has_loglevel = 0;
 918
 919         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 920         if (strcmp(desc->name, enabler->event_param.name))
 921                 return 0;
 922         if (desc->loglevel) {
 923                 loglevel = *(*desc->loglevel);
 924                 has_loglevel = 1;
 925         }
 926         if (!lttng_loglevel_match(loglevel,
 927                         has_loglevel,
 928                         enabler->event_param.loglevel_type,
 929                         enabler->event_param.loglevel))
 930                 return 0;
 931         return 1;
 932 }
 933
 934 static
 935 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 936                 struct lttng_enabler *enabler)
 937 {
 938         switch (enabler->format_type) {
 939         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 940         {
 941                 struct lttng_ust_excluder_node *excluder;
 942
 943                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 944                         return 0;
 945                 }
 946
 947                 /*
 948                  * If the matching event matches with an excluder,
 949                  * return 'does not match'
 950                  */
 951                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 952                         int count;
 953
 954                         for (count = 0; count < excluder->excluder.count; count++) {
 955                                 int len;
 956                                 char *excluder_name;
 957
 958                                 excluder_name = (char *) (excluder->excluder.names)
 959                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 960                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 961                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 962                                         return 0;
 963                         }
 964                 }
 965                 return 1;
 966         }
 967         case LTTNG_ENABLER_FORMAT_EVENT:
 968                 return lttng_desc_match_event_enabler(desc, enabler);
 969         default:
 970                 return -EINVAL;
 971         }
 972 }
 973
 974 static
 975 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 976                 struct lttng_event *event)
 977 {
 978         if (lttng_desc_match_enabler(event->desc,
 979                         lttng_event_enabler_as_enabler(event_enabler))
 980                         && event->chan == event_enabler->chan)
 981                 return 1;
 982         else
 983                 return 0;
 984 }
 985
 986 static
 987 int lttng_event_notifier_enabler_match_event_notifier(
 988                 struct lttng_event_notifier_enabler *event_notifier_enabler,
 989                 struct lttng_event_notifier *event_notifier)
 990 {
 991         int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
 992                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 993
 994         if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
 995                         event_notifier->user_token == event_notifier_enabler->user_token)
 996                 return 1;
 997         else
 998                 return 0;
 999 }
1000
1001 static
1002 struct lttng_enabler_ref *lttng_enabler_ref(
1003                 struct cds_list_head *enabler_ref_list,
1004                 struct lttng_enabler *enabler)
1005 {
1006         struct lttng_enabler_ref *enabler_ref;
1007
1008         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1009                 if (enabler_ref->ref == enabler)
1010                         return enabler_ref;
1011         }
1012         return NULL;
1013 }
1014
1015 /*
1016  * Create struct lttng_event if it is missing and present in the list of
1017  * tracepoint probes.
1018  */
1019 static
1020 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1021 {
1022         struct lttng_session *session = event_enabler->chan->session;
1023         struct lttng_probe_desc *probe_desc;
1024         const struct lttng_event_desc *desc;
1025         struct lttng_event *event;
1026         int i;
1027         struct cds_list_head *probe_list;
1028
1029         probe_list = lttng_get_probe_list_head();
1030         /*
1031          * For each probe event, if we find that a probe event matches
1032          * our enabler, create an associated lttng_event if not
1033          * already present.
1034          */
1035         cds_list_for_each_entry(probe_desc, probe_list, head) {
1036                 for (i = 0; i < probe_desc->nr_events; i++) {
1037                         int ret;
1038                         bool found = false;
1039                         struct cds_hlist_head *head;
1040                         struct cds_hlist_node *node;
1041
1042                         desc = probe_desc->event_desc[i];
1043                         if (!lttng_desc_match_enabler(desc,
1044                                         lttng_event_enabler_as_enabler(event_enabler)))
1045                                 continue;
1046
1047                         head = borrow_hash_table_bucket(
1048                                 session->events_ht.table,
1049                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1050
1051                         cds_hlist_for_each_entry(event, node, head, hlist) {
1052                                 if (event->desc == desc
1053                                                 && event->chan == event_enabler->chan) {
1054                                         found = true;
1055                                         break;
1056                                 }
1057                         }
1058                         if (found)
1059                                 continue;
1060
1061                         /*
1062                          * We need to create an event for this
1063                          * event probe.
1064                          */
1065                         ret = lttng_event_create(probe_desc->event_desc[i],
1066                                         event_enabler->chan);
1067                         if (ret) {
1068                                 DBG("Unable to create event %s, error %d\n",
1069                                         probe_desc->event_desc[i]->name, ret);
1070                         }
1071                 }
1072         }
1073 }
1074
1075 static
1076 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1077                 void (*event_func)(struct lttng_session *session,
1078                         struct lttng_event *event),
1079                 void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
1080 {
1081         struct cds_hlist_node *node, *tmp_node;
1082         struct cds_list_head *sessionsp;
1083         unsigned int i;
1084
1085         /* Get handle on list of sessions. */
1086         sessionsp = _lttng_get_sessions();
1087
1088         /*
1089          * Iterate over all events in the probe provider descriptions and
1090          * sessions to queue the unregistration of the events.
1091          */
1092         for (i = 0; i < provider_desc->nr_events; i++) {
1093                 const struct lttng_event_desc *event_desc;
1094                 struct lttng_event_notifier_group *event_notifier_group;
1095                 struct lttng_event_notifier *event_notifier;
1096                 struct lttng_session *session;
1097                 struct cds_hlist_head *head;
1098                 struct lttng_event *event;
1099
1100                 event_desc = provider_desc->event_desc[i];
1101
1102                 /*
1103                  * Iterate over all session to find the current event
1104                  * description.
1105                  */
1106                 cds_list_for_each_entry(session, sessionsp, node) {
1107                         /*
1108                          * Get the list of events in the hashtable bucket and
1109                          * iterate to find the event matching this descriptor.
1110                          */
1111                         head = borrow_hash_table_bucket(
1112                                 session->events_ht.table,
1113                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1114
1115                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1116                                 if (event_desc == event->desc) {
1117                                         event_func(session, event);
1118                                         break;
1119                                 }
1120                         }
1121                 }
1122
1123                 /*
1124                  * Iterate over all event_notifier groups to find the current event
1125                  * description.
1126                  */
1127                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1128                         /*
1129                          * Get the list of event_notifiers in the hashtable bucket and
1130                          * iterate to find the event_notifier matching this
1131                          * descriptor.
1132                          */
1133                         head = borrow_hash_table_bucket(
1134                                 event_notifier_group->event_notifiers_ht.table,
1135                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1136
1137                         cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
1138                                 if (event_desc == event_notifier->desc) {
1139                                         event_notifier_func(event_notifier);
1140                                         break;
1141                                 }
1142                         }
1143                 }
1144         }
1145 }
1146
1147 static
1148 void _unregister_event(struct lttng_session *session,
1149                 struct lttng_event *event)
1150 {
1151         _lttng_event_unregister(event);
1152 }
1153
1154 static
1155 void _event_enum_destroy(struct lttng_session *session,
1156                 struct lttng_event *event)
1157 {
1158         unsigned int i;
1159
1160         /* Destroy enums of the current event. */
1161         for (i = 0; i < event->desc->nr_fields; i++) {
1162                 const struct lttng_enum_desc *enum_desc;
1163                 const struct lttng_event_field *field;
1164                 struct lttng_enum *curr_enum;
1165
1166                 field = &(event->desc->fields[i]);
1167                 switch (field->type.atype) {
1168                 case atype_enum:
1169                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1170                         break;
1171                 case atype_enum_nestable:
1172                         enum_desc = field->type.u.enum_nestable.desc;
1173                         break;
1174                 default:
1175                         continue;
1176                 }
1177
1178                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1179                 if (curr_enum) {
1180                         _lttng_enum_destroy(curr_enum);
1181                 }
1182         }
1183
1184         /* Destroy event. */
1185         _lttng_event_destroy(event);
1186 }
1187
1188 /*
1189  * Iterate over all the UST sessions to unregister and destroy all probes from
1190  * the probe provider descriptor received as argument. Must me called with the
1191  * ust_lock held.
1192  */
1193 void lttng_probe_provider_unregister_events(
1194                 struct lttng_probe_desc *provider_desc)
1195 {
1196         /*
1197          * Iterate over all events in the probe provider descriptions and sessions
1198          * to queue the unregistration of the events.
1199          */
1200         probe_provider_event_for_each(provider_desc, _unregister_event,
1201                 _lttng_event_notifier_unregister);
1202
1203         /* Wait for grace period. */
1204         lttng_ust_synchronize_trace();
1205         /* Prune the unregistration queue. */
1206         __tracepoint_probe_prune_release_queue();
1207
1208         /*
1209          * It is now safe to destroy the events and remove them from the event list
1210          * and hashtables.
1211          */
1212         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1213                 _lttng_event_notifier_destroy);
1214 }
1215
1216 /*
1217  * Create events associated with an event enabler (if not already present),
1218  * and add backward reference from the event to the enabler.
1219  */
1220 static
1221 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1222 {
1223         struct lttng_session *session = event_enabler->chan->session;
1224         struct lttng_event *event;
1225
1226         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1227                 goto end;
1228
1229         /* First ensure that probe events are created for this enabler. */
1230         lttng_create_event_if_missing(event_enabler);
1231
1232         /* For each event matching enabler in session event list. */
1233         cds_list_for_each_entry(event, &session->events_head, node) {
1234                 struct lttng_enabler_ref *enabler_ref;
1235
1236                 if (!lttng_event_enabler_match_event(event_enabler, event))
1237                         continue;
1238
1239                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1240                         lttng_event_enabler_as_enabler(event_enabler));
1241                 if (!enabler_ref) {
1242                         /*
1243                          * If no backward ref, create it.
1244                          * Add backward ref from event to enabler.
1245                          */
1246                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1247                         if (!enabler_ref)
1248                                 return -ENOMEM;
1249                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1250                                 event_enabler);
1251                         cds_list_add(&enabler_ref->node,
1252                                 &event->enablers_ref_head);
1253                 }
1254
1255                 /*
1256                  * Link filter bytecodes if not linked yet.
1257                  */
1258                 lttng_enabler_link_bytecode(event->desc,
1259                         &session->ctx,
1260                         &event->filter_bytecode_runtime_head,
1261                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1262
1263                 /* TODO: merge event context. */
1264         }
1265 end:
1266         return 0;
1267 }
1268
1269 /*
1270  * Called at library load: connect the probe on all enablers matching
1271  * this event.
1272  * Called with session mutex held.
1273  */
1274 int lttng_fix_pending_events(void)
1275 {
1276         struct lttng_session *session;
1277
1278         cds_list_for_each_entry(session, &sessions, node) {
1279                 lttng_session_lazy_sync_event_enablers(session);
1280         }
1281         return 0;
1282 }
1283
1284 int lttng_fix_pending_event_notifiers(void)
1285 {
1286         struct lttng_event_notifier_group *event_notifier_group;
1287
1288         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1289                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1290         }
1291         return 0;
1292 }
1293
1294 /*
1295  * For each session of the owner thread, execute pending statedump.
1296  * Only dump state for the sessions owned by the caller thread, because
1297  * we don't keep ust_lock across the entire iteration.
1298  */
1299 void lttng_handle_pending_statedump(void *owner)
1300 {
1301         struct lttng_session *session;
1302
1303         /* Execute state dump */
1304         do_lttng_ust_statedump(owner);
1305
1306         /* Clear pending state dump */
1307         if (ust_lock()) {
1308                 goto end;
1309         }
1310         cds_list_for_each_entry(session, &sessions, node) {
1311                 if (session->owner != owner)
1312                         continue;
1313                 if (!session->statedump_pending)
1314                         continue;
1315                 session->statedump_pending = 0;
1316         }
1317 end:
1318         ust_unlock();
1319         return;
1320 }
1321
1322 /*
1323  * Only used internally at session destruction.
1324  */
1325 static
1326 void _lttng_event_destroy(struct lttng_event *event)
1327 {
1328         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1329
1330         /* Remove from event list. */
1331         cds_list_del(&event->node);
1332         /* Remove from event hash table. */
1333         cds_hlist_del(&event->hlist);
1334
1335         lttng_destroy_context(event->ctx);
1336         lttng_free_event_filter_runtime(event);
1337         /* Free event enabler refs */
1338         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1339                         &event->enablers_ref_head, node)
1340                 free(enabler_ref);
1341         free(event);
1342 }
1343
1344 static
1345 void _lttng_enum_destroy(struct lttng_enum *_enum)
1346 {
1347         cds_list_del(&_enum->node);
1348         cds_hlist_del(&_enum->hlist);
1349         free(_enum);
1350 }
1351
1352 void lttng_ust_events_exit(void)
1353 {
1354         struct lttng_session *session, *tmpsession;
1355
1356         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1357                 lttng_session_destroy(session);
1358 }
1359
1360 /*
1361  * Enabler management.
1362  */
1363 struct lttng_event_enabler *lttng_event_enabler_create(
1364                 enum lttng_enabler_format_type format_type,
1365                 struct lttng_ust_event *event_param,
1366                 struct lttng_channel *chan)
1367 {
1368         struct lttng_event_enabler *event_enabler;
1369
1370         event_enabler = zmalloc(sizeof(*event_enabler));
1371         if (!event_enabler)
1372                 return NULL;
1373         event_enabler->base.format_type = format_type;
1374         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1375         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1376         memcpy(&event_enabler->base.event_param, event_param,
1377                 sizeof(event_enabler->base.event_param));
1378         event_enabler->chan = chan;
1379         /* ctx left NULL */
1380         event_enabler->base.enabled = 0;
1381         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1382         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1383
1384         return event_enabler;
1385 }
1386
1387 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1388                 struct lttng_event_notifier_group *event_notifier_group,
1389                 enum lttng_enabler_format_type format_type,
1390                 struct lttng_ust_event_notifier *event_notifier_param)
1391 {
1392         struct lttng_event_notifier_enabler *event_notifier_enabler;
1393
1394         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1395         if (!event_notifier_enabler)
1396                 return NULL;
1397         event_notifier_enabler->base.format_type = format_type;
1398         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1399         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1400         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1401
1402         event_notifier_enabler->user_token = event_notifier_param->event.token;
1403         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1404         event_notifier_enabler->num_captures = 0;
1405
1406         memcpy(&event_notifier_enabler->base.event_param.name,
1407                 event_notifier_param->event.name,
1408                 sizeof(event_notifier_enabler->base.event_param.name));
1409         event_notifier_enabler->base.event_param.instrumentation =
1410                 event_notifier_param->event.instrumentation;
1411         event_notifier_enabler->base.event_param.loglevel =
1412                 event_notifier_param->event.loglevel;
1413         event_notifier_enabler->base.event_param.loglevel_type =
1414                 event_notifier_param->event.loglevel_type;
1415
1416         event_notifier_enabler->base.enabled = 0;
1417         event_notifier_enabler->group = event_notifier_group;
1418
1419         cds_list_add(&event_notifier_enabler->node,
1420                         &event_notifier_group->enablers_head);
1421
1422         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1423
1424         return event_notifier_enabler;
1425 }
1426
1427 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1428 {
1429         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1430         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1431
1432         return 0;
1433 }
1434
1435 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1436 {
1437         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1438         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1439
1440         return 0;
1441 }
1442
1443 static
1444 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1445                 struct lttng_ust_bytecode_node **bytecode)
1446 {
1447         (*bytecode)->enabler = enabler;
1448         cds_list_add_tail(&(*bytecode)->node, &enabler->filter_bytecode_head);
1449         /* Take ownership of bytecode */
1450         *bytecode = NULL;
1451 }
1452
1453 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1454                 struct lttng_ust_bytecode_node **bytecode)
1455 {
1456         _lttng_enabler_attach_filter_bytecode(
1457                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1458
1459         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1460         return 0;
1461 }
1462
1463 static
1464 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1465                 struct lttng_ust_excluder_node **excluder)
1466 {
1467         (*excluder)->enabler = enabler;
1468         cds_list_add_tail(&(*excluder)->node, &enabler->excluder_head);
1469         /* Take ownership of excluder */
1470         *excluder = NULL;
1471 }
1472
1473 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1474                 struct lttng_ust_excluder_node **excluder)
1475 {
1476         _lttng_enabler_attach_exclusion(
1477                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1478
1479         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1480         return 0;
1481 }
1482
1483 int lttng_event_notifier_enabler_enable(
1484                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1485 {
1486         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1487         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1488
1489         return 0;
1490 }
1491
1492 int lttng_event_notifier_enabler_disable(
1493                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1494 {
1495         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1496         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1497
1498         return 0;
1499 }
1500
1501 int lttng_event_notifier_enabler_attach_filter_bytecode(
1502                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1503                 struct lttng_ust_bytecode_node **bytecode)
1504 {
1505         _lttng_enabler_attach_filter_bytecode(
1506                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1507                 bytecode);
1508
1509         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1510         return 0;
1511 }
1512
1513 int lttng_event_notifier_enabler_attach_capture_bytecode(
1514                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1515                 struct lttng_ust_bytecode_node **bytecode)
1516 {
1517         (*bytecode)->enabler = lttng_event_notifier_enabler_as_enabler(
1518                         event_notifier_enabler);
1519         cds_list_add_tail(&(*bytecode)->node,
1520                         &event_notifier_enabler->capture_bytecode_head);
1521         /* Take ownership of bytecode */
1522         *bytecode = NULL;
1523         event_notifier_enabler->num_captures++;
1524
1525         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1526         return 0;
1527 }
1528
1529 int lttng_event_notifier_enabler_attach_exclusion(
1530                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1531                 struct lttng_ust_excluder_node **excluder)
1532 {
1533         _lttng_enabler_attach_exclusion(
1534                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1535                 excluder);
1536
1537         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1538         return 0;
1539 }
1540
1541 int lttng_attach_context(struct lttng_ust_context *context_param,
1542                 union ust_args *uargs,
1543                 struct lttng_ctx **ctx, struct lttng_session *session)
1544 {
1545         /*
1546          * We cannot attach a context after trace has been started for a
1547          * session because the metadata does not allow expressing this
1548          * information outside of the original channel scope.
1549          */
1550         if (session->been_active)
1551                 return -EPERM;
1552
1553         switch (context_param->ctx) {
1554         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1555                 return lttng_add_pthread_id_to_ctx(ctx);
1556         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1557         {
1558                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1559
1560                 perf_ctx_param = &context_param->u.perf_counter;
1561                 return lttng_add_perf_counter_to_ctx(
1562                         perf_ctx_param->type,
1563                         perf_ctx_param->config,
1564                         perf_ctx_param->name,
1565                         ctx);
1566         }
1567         case LTTNG_UST_CONTEXT_VTID:
1568                 return lttng_add_vtid_to_ctx(ctx);
1569         case LTTNG_UST_CONTEXT_VPID:
1570                 return lttng_add_vpid_to_ctx(ctx);
1571         case LTTNG_UST_CONTEXT_PROCNAME:
1572                 return lttng_add_procname_to_ctx(ctx);
1573         case LTTNG_UST_CONTEXT_IP:
1574                 return lttng_add_ip_to_ctx(ctx);
1575         case LTTNG_UST_CONTEXT_CPU_ID:
1576                 return lttng_add_cpu_id_to_ctx(ctx);
1577         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1578                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1579                         ctx);
1580         case LTTNG_UST_CONTEXT_CGROUP_NS:
1581                 return lttng_add_cgroup_ns_to_ctx(ctx);
1582         case LTTNG_UST_CONTEXT_IPC_NS:
1583                 return lttng_add_ipc_ns_to_ctx(ctx);
1584         case LTTNG_UST_CONTEXT_MNT_NS:
1585                 return lttng_add_mnt_ns_to_ctx(ctx);
1586         case LTTNG_UST_CONTEXT_NET_NS:
1587                 return lttng_add_net_ns_to_ctx(ctx);
1588         case LTTNG_UST_CONTEXT_PID_NS:
1589                 return lttng_add_pid_ns_to_ctx(ctx);
1590         case LTTNG_UST_CONTEXT_TIME_NS:
1591                 return lttng_add_time_ns_to_ctx(ctx);
1592         case LTTNG_UST_CONTEXT_USER_NS:
1593                 return lttng_add_user_ns_to_ctx(ctx);
1594         case LTTNG_UST_CONTEXT_UTS_NS:
1595                 return lttng_add_uts_ns_to_ctx(ctx);
1596         case LTTNG_UST_CONTEXT_VUID:
1597                 return lttng_add_vuid_to_ctx(ctx);
1598         case LTTNG_UST_CONTEXT_VEUID:
1599                 return lttng_add_veuid_to_ctx(ctx);
1600         case LTTNG_UST_CONTEXT_VSUID:
1601                 return lttng_add_vsuid_to_ctx(ctx);
1602         case LTTNG_UST_CONTEXT_VGID:
1603                 return lttng_add_vgid_to_ctx(ctx);
1604         case LTTNG_UST_CONTEXT_VEGID:
1605                 return lttng_add_vegid_to_ctx(ctx);
1606         case LTTNG_UST_CONTEXT_VSGID:
1607                 return lttng_add_vsgid_to_ctx(ctx);
1608         default:
1609                 return -EINVAL;
1610         }
1611 }
1612
1613 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1614                 struct lttng_ust_context *context_param)
1615 {
1616         return -ENOSYS;
1617 }
1618
1619 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1620 {
1621         if (!event_enabler) {
1622                 return;
1623         }
1624         cds_list_del(&event_enabler->node);
1625
1626         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1627
1628         lttng_destroy_context(event_enabler->ctx);
1629         free(event_enabler);
1630 }
1631
1632 /*
1633  * lttng_session_sync_event_enablers should be called just before starting a
1634  * session.
1635  */
1636 static
1637 void lttng_session_sync_event_enablers(struct lttng_session *session)
1638 {
1639         struct lttng_event_enabler *event_enabler;
1640         struct lttng_event *event;
1641
1642         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1643                 lttng_event_enabler_ref_events(event_enabler);
1644         /*
1645          * For each event, if at least one of its enablers is enabled,
1646          * and its channel and session transient states are enabled, we
1647          * enable the event, else we disable it.
1648          */
1649         cds_list_for_each_entry(event, &session->events_head, node) {
1650                 struct lttng_enabler_ref *enabler_ref;
1651                 struct lttng_bytecode_runtime *runtime;
1652                 int enabled = 0, has_enablers_without_bytecode = 0;
1653
1654                 /* Enable events */
1655                 cds_list_for_each_entry(enabler_ref,
1656                                 &event->enablers_ref_head, node) {
1657                         if (enabler_ref->ref->enabled) {
1658                                 enabled = 1;
1659                                 break;
1660                         }
1661                 }
1662                 /*
1663                  * Enabled state is based on union of enablers, with
1664                  * intesection of session and channel transient enable
1665                  * states.
1666                  */
1667                 enabled = enabled && session->tstate && event->chan->tstate;
1668
1669                 CMM_STORE_SHARED(event->enabled, enabled);
1670                 /*
1671                  * Sync tracepoint registration with event enabled
1672                  * state.
1673                  */
1674                 if (enabled) {
1675                         if (!event->registered)
1676                                 register_event(event);
1677                 } else {
1678                         if (event->registered)
1679                                 unregister_event(event);
1680                 }
1681
1682                 /* Check if has enablers without bytecode enabled */
1683                 cds_list_for_each_entry(enabler_ref,
1684                                 &event->enablers_ref_head, node) {
1685                         if (enabler_ref->ref->enabled
1686                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1687                                 has_enablers_without_bytecode = 1;
1688                                 break;
1689                         }
1690                 }
1691                 event->has_enablers_without_bytecode =
1692                         has_enablers_without_bytecode;
1693
1694                 /* Enable filters */
1695                 cds_list_for_each_entry(runtime,
1696                                 &event->filter_bytecode_runtime_head, node) {
1697                         lttng_bytecode_filter_sync_state(runtime);
1698                 }
1699         }
1700         __tracepoint_probe_prune_release_queue();
1701 }
1702
1703 /* Support for event notifier is introduced by probe provider major version 2. */
1704 static
1705 bool lttng_ust_probe_supports_event_notifier(struct lttng_probe_desc *probe_desc)
1706 {
1707         return probe_desc->major >= 2;
1708 }
1709
1710 static
1711 void lttng_create_event_notifier_if_missing(
1712                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1713 {
1714         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1715         struct lttng_probe_desc *probe_desc;
1716         struct cds_list_head *probe_list;
1717         int i;
1718
1719         probe_list = lttng_get_probe_list_head();
1720
1721         cds_list_for_each_entry(probe_desc, probe_list, head) {
1722                 for (i = 0; i < probe_desc->nr_events; i++) {
1723                         int ret;
1724                         bool found = false;
1725                         const struct lttng_event_desc *desc;
1726                         struct lttng_event_notifier *event_notifier;
1727                         struct cds_hlist_head *head;
1728                         struct cds_hlist_node *node;
1729
1730                         desc = probe_desc->event_desc[i];
1731
1732                         if (!lttng_desc_match_enabler(desc,
1733                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1734                                 continue;
1735
1736                         /*
1737                          * Given the current event_notifier group, get the bucket that
1738                          * the target event_notifier would be if it was already
1739                          * created.
1740                          */
1741                         head = borrow_hash_table_bucket(
1742                                 event_notifier_group->event_notifiers_ht.table,
1743                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1744
1745                         cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
1746                                 /*
1747                                  * Check if event_notifier already exists by checking
1748                                  * if the event_notifier and enabler share the same
1749                                  * description and id.
1750                                  */
1751                                 if (event_notifier->desc == desc &&
1752                                                 event_notifier->user_token == event_notifier_enabler->user_token) {
1753                                         found = true;
1754                                         break;
1755                                 }
1756                         }
1757
1758                         if (found)
1759                                 continue;
1760
1761                         /* Check that the probe supports event notifiers, else report the error. */
1762                         if (!lttng_ust_probe_supports_event_notifier(probe_desc)) {
1763                                 ERR("Probe \"%s\" contains event \"%s\" which matches an enabled event notifier, "
1764                                         "but its version (%u.%u) is too old and does not implement event notifiers. "
1765                                         "It needs to be recompiled against a newer version of LTTng-UST, otherwise "
1766                                         "this event will not generate any notification.",
1767                                         probe_desc->provider,
1768                                         desc->name,
1769                                         probe_desc->major,
1770                                         probe_desc->minor);
1771                                 continue;
1772                         }
1773                         /*
1774                          * We need to create a event_notifier for this event probe.
1775                          */
1776                         ret = lttng_event_notifier_create(desc,
1777                                 event_notifier_enabler->user_token,
1778                                 event_notifier_enabler->error_counter_index,
1779                                 event_notifier_group);
1780                         if (ret) {
1781                                 DBG("Unable to create event_notifier %s, error %d\n",
1782                                         probe_desc->event_desc[i]->name, ret);
1783                         }
1784                 }
1785         }
1786 }
1787
1788 /*
1789  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1790  */
1791 static
1792 int lttng_event_notifier_enabler_ref_event_notifiers(
1793                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1794 {
1795         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1796         struct lttng_event_notifier *event_notifier;
1797
1798          /*
1799           * Only try to create event_notifiers for enablers that are enabled, the user
1800           * might still be attaching filter or exclusion to the
1801           * event_notifier_enabler.
1802           */
1803         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1804                 goto end;
1805
1806         /* First, ensure that probe event_notifiers are created for this enabler. */
1807         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1808
1809         /* Link the created event_notifier with its associated enabler. */
1810         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1811                 struct lttng_enabler_ref *enabler_ref;
1812
1813                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
1814                         continue;
1815
1816                 enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
1817                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1818                 if (!enabler_ref) {
1819                         /*
1820                          * If no backward ref, create it.
1821                          * Add backward ref from event_notifier to enabler.
1822                          */
1823                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1824                         if (!enabler_ref)
1825                                 return -ENOMEM;
1826
1827                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1828                                 event_notifier_enabler);
1829                         cds_list_add(&enabler_ref->node,
1830                                 &event_notifier->enablers_ref_head);
1831                 }
1832
1833                 /*
1834                  * Link filter bytecodes if not linked yet.
1835                  */
1836                 lttng_enabler_link_bytecode(event_notifier->desc,
1837                         &event_notifier_group->ctx,
1838                         &event_notifier->filter_bytecode_runtime_head,
1839                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1840
1841                 /*
1842                  * Link capture bytecodes if not linked yet.
1843                  */
1844                 lttng_enabler_link_bytecode(event_notifier->desc,
1845                         &event_notifier_group->ctx, &event_notifier->capture_bytecode_runtime_head,
1846                         &event_notifier_enabler->capture_bytecode_head);
1847
1848                 event_notifier->num_captures = event_notifier_enabler->num_captures;
1849         }
1850 end:
1851         return 0;
1852 }
1853
1854 static
1855 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1856 {
1857         struct lttng_event_notifier_enabler *event_notifier_enabler;
1858         struct lttng_event_notifier *event_notifier;
1859
1860         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1861                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1862
1863         /*
1864          * For each event_notifier, if at least one of its enablers is enabled,
1865          * we enable the event_notifier, else we disable it.
1866          */
1867         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1868                 struct lttng_enabler_ref *enabler_ref;
1869                 struct lttng_bytecode_runtime *runtime;
1870                 int enabled = 0, has_enablers_without_bytecode = 0;
1871
1872                 /* Enable event_notifiers */
1873                 cds_list_for_each_entry(enabler_ref,
1874                                 &event_notifier->enablers_ref_head, node) {
1875                         if (enabler_ref->ref->enabled) {
1876                                 enabled = 1;
1877                                 break;
1878                         }
1879                 }
1880
1881                 CMM_STORE_SHARED(event_notifier->enabled, enabled);
1882                 /*
1883                  * Sync tracepoint registration with event_notifier enabled
1884                  * state.
1885                  */
1886                 if (enabled) {
1887                         if (!event_notifier->registered)
1888                                 register_event_notifier(event_notifier);
1889                 } else {
1890                         if (event_notifier->registered)
1891                                 unregister_event_notifier(event_notifier);
1892                 }
1893
1894                 /* Check if has enablers without bytecode enabled */
1895                 cds_list_for_each_entry(enabler_ref,
1896                                 &event_notifier->enablers_ref_head, node) {
1897                         if (enabler_ref->ref->enabled
1898                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1899                                 has_enablers_without_bytecode = 1;
1900                                 break;
1901                         }
1902                 }
1903                 event_notifier->has_enablers_without_bytecode =
1904                         has_enablers_without_bytecode;
1905
1906                 /* Enable filters */
1907                 cds_list_for_each_entry(runtime,
1908                                 &event_notifier->filter_bytecode_runtime_head, node) {
1909                         lttng_bytecode_filter_sync_state(runtime);
1910                 }
1911
1912                 /* Enable captures. */
1913                 cds_list_for_each_entry(runtime,
1914                                 &event_notifier->capture_bytecode_runtime_head, node) {
1915                         lttng_bytecode_capture_sync_state(runtime);
1916                 }
1917         }
1918         __tracepoint_probe_prune_release_queue();
1919 }
1920
1921 /*
1922  * Apply enablers to session events, adding events to session if need
1923  * be. It is required after each modification applied to an active
1924  * session, and right before session "start".
1925  * "lazy" sync means we only sync if required.
1926  */
1927 static
1928 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1929 {
1930         /* We can skip if session is not active */
1931         if (!session->active)
1932                 return;
1933         lttng_session_sync_event_enablers(session);
1934 }
1935
1936 /*
1937  * Update all sessions with the given app context.
1938  * Called with ust lock held.
1939  * This is invoked when an application context gets loaded/unloaded. It
1940  * ensures the context callbacks are in sync with the application
1941  * context (either app context callbacks, or dummy callbacks).
1942  */
1943 void lttng_ust_context_set_session_provider(const char *name,
1944                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1945                 void (*record)(struct lttng_ctx_field *field,
1946                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1947                         struct lttng_channel *chan),
1948                 void (*get_value)(struct lttng_ctx_field *field,
1949                         struct lttng_ctx_value *value))
1950 {
1951         struct lttng_session *session;
1952
1953         cds_list_for_each_entry(session, &sessions, node) {
1954                 struct lttng_channel *chan;
1955                 struct lttng_event *event;
1956                 int ret;
1957
1958                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1959                                 name, get_size, record, get_value);
1960                 if (ret)
1961                         abort();
1962                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1963                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1964                                         name, get_size, record, get_value);
1965                         if (ret)
1966                                 abort();
1967                 }
1968                 cds_list_for_each_entry(event, &session->events_head, node) {
1969                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1970                                         name, get_size, record, get_value);
1971                         if (ret)
1972                                 abort();
1973                 }
1974         }
1975 }
1976
1977 /*
1978  * Update all event_notifier groups with the given app context.
1979  * Called with ust lock held.
1980  * This is invoked when an application context gets loaded/unloaded. It
1981  * ensures the context callbacks are in sync with the application
1982  * context (either app context callbacks, or dummy callbacks).
1983  */
1984 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
1985                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1986                 void (*record)(struct lttng_ctx_field *field,
1987                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1988                         struct lttng_channel *chan),
1989                 void (*get_value)(struct lttng_ctx_field *field,
1990                         struct lttng_ctx_value *value))
1991 {
1992         struct lttng_event_notifier_group *event_notifier_group;
1993
1994         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1995                 int ret;
1996
1997                 ret = lttng_ust_context_set_provider_rcu(
1998                                 &event_notifier_group->ctx,
1999                                 name, get_size, record, get_value);
2000                 if (ret)
2001                         abort();
2002         }
2003 }