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