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