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-bytecode.h"
  64 #include "lttng-tracer.h"
  65 #include "lttng-tracer-core.h"
  66 #include "lttng-ust-statedump.h"
  67 #include "context-internal.h"
  68 #include "ust-events-internal.h"
  69 #include "wait.h"
  70 #include "../libringbuffer/shm.h"
  71 #include "../libcounter/counter.h"
  72 #include "jhash.h"
  73 #include <lttng/ust-abi.h>
  74
  75 /*
  76  * All operations within this file are called by the communication
  77  * thread, under ust_lock protection.
  78  */
  79
  80 static CDS_LIST_HEAD(sessions);
  81 static CDS_LIST_HEAD(trigger_groups);
  82
  83 struct cds_list_head *_lttng_get_sessions(void)
  84 {
  85         return &sessions;
  86 }
  87
  88 static void _lttng_event_destroy(struct lttng_event *event);
  89 static void _lttng_trigger_destroy(struct lttng_trigger *trigger);
  90 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  91
  92 static
  93 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  94 static
  95 void lttng_session_sync_event_enablers(struct lttng_session *session);
  96 static
  97 void lttng_trigger_group_sync_enablers(struct lttng_trigger_group *trigger_group);
  98 static
  99 void lttng_enabler_destroy(struct lttng_enabler *enabler);
 100
 101 /*
 102  * Called with ust lock held.
 103  */
 104 int lttng_session_active(void)
 105 {
 106         struct lttng_session *iter;
 107
 108         cds_list_for_each_entry(iter, &sessions, node) {
 109                 if (iter->active)
 110                         return 1;
 111         }
 112         return 0;
 113 }
 114
 115 static
 116 int lttng_loglevel_match(int loglevel,
 117                 unsigned int has_loglevel,
 118                 enum lttng_ust_loglevel_type req_type,
 119                 int req_loglevel)
 120 {
 121         if (!has_loglevel)
 122                 loglevel = TRACE_DEFAULT;
 123         switch (req_type) {
 124         case LTTNG_UST_LOGLEVEL_RANGE:
 125                 if (loglevel <= req_loglevel
 126                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 127                         return 1;
 128                 else
 129                         return 0;
 130         case LTTNG_UST_LOGLEVEL_SINGLE:
 131                 if (loglevel == req_loglevel
 132                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 133                         return 1;
 134                 else
 135                         return 0;
 136         case LTTNG_UST_LOGLEVEL_ALL:
 137         default:
 138                 if (loglevel <= TRACE_DEBUG)
 139                         return 1;
 140                 else
 141                         return 0;
 142         }
 143 }
 144
 145 void synchronize_trace(void)
 146 {
 147         synchronize_rcu();
 148 }
 149
 150 struct lttng_session *lttng_session_create(void)
 151 {
 152         struct lttng_session *session;
 153         int i;
 154
 155         session = zmalloc(sizeof(struct lttng_session));
 156         if (!session)
 157                 return NULL;
 158         if (lttng_context_init_all(&session->ctx)) {
 159                 free(session);
 160                 return NULL;
 161         }
 162         CDS_INIT_LIST_HEAD(&session->chan_head);
 163         CDS_INIT_LIST_HEAD(&session->events_head);
 164         CDS_INIT_LIST_HEAD(&session->enums_head);
 165         CDS_INIT_LIST_HEAD(&session->enablers_head);
 166         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 167                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 168         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 169                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 170         cds_list_add(&session->node, &sessions);
 171         return session;
 172 }
 173
 174 struct lttng_counter *lttng_ust_counter_create(
 175                 const char *counter_transport_name,
 176                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 177 {
 178         struct lttng_counter_transport *counter_transport = NULL;
 179         struct lttng_counter *counter = NULL;
 180
 181         counter_transport = lttng_counter_transport_find(counter_transport_name);
 182         if (!counter_transport)
 183                 goto notransport;
 184         counter = zmalloc(sizeof(struct lttng_counter));
 185         if (!counter)
 186                 goto nomem;
 187
 188         /* Create trigger error counter. */
 189         counter->ops = &counter_transport->ops;
 190         counter->transport = counter_transport;
 191
 192         counter->counter = counter->ops->counter_create(
 193                         number_dimensions, dimensions, 0,
 194                         -1, 0, NULL, false);
 195         if (!counter->counter) {
 196                 goto create_error;
 197         }
 198
 199         return counter;
 200
 201 create_error:
 202         free(counter);
 203 nomem:
 204 notransport:
 205         return NULL;
 206 }
 207
 208 static
 209 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 210 {
 211         counter->ops->counter_destroy(counter->counter);
 212         free(counter);
 213 }
 214
 215 struct lttng_trigger_group *lttng_trigger_group_create(void)
 216 {
 217         struct lttng_trigger_group *trigger_group;
 218         int i;
 219
 220         trigger_group = zmalloc(sizeof(struct lttng_trigger_group));
 221         if (!trigger_group)
 222                 return NULL;
 223
 224         /* Add all contexts. */
 225         if (lttng_context_init_all(&trigger_group->ctx)) {
 226                 free(trigger_group);
 227                 return NULL;
 228         }
 229
 230         CDS_INIT_LIST_HEAD(&trigger_group->enablers_head);
 231         CDS_INIT_LIST_HEAD(&trigger_group->triggers_head);
 232         for (i = 0; i < LTTNG_UST_TRIGGER_HT_SIZE; i++)
 233                 CDS_INIT_HLIST_HEAD(&trigger_group->triggers_ht.table[i]);
 234
 235         cds_list_add(&trigger_group->node, &trigger_groups);
 236
 237         return trigger_group;
 238 }
 239
 240 /*
 241  * Only used internally at session destruction.
 242  */
 243 static
 244 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 245 {
 246         struct channel *chan;
 247         struct lttng_ust_shm_handle *handle;
 248
 249         cds_list_del(&lttng_chan->node);
 250         lttng_destroy_context(lttng_chan->ctx);
 251         chan = lttng_chan->chan;
 252         handle = lttng_chan->handle;
 253         /*
 254          * note: lttng_chan is private data contained within handle. It
 255          * will be freed along with the handle.
 256          */
 257         channel_destroy(chan, handle, 0);
 258 }
 259
 260 static
 261 void register_event(struct lttng_event *event)
 262 {
 263         int ret;
 264         const struct lttng_event_desc *desc;
 265
 266         assert(event->registered == 0);
 267         desc = event->desc;
 268         ret = __tracepoint_probe_register_queue_release(desc->name,
 269                         desc->probe_callback,
 270                         event, desc->signature);
 271         WARN_ON_ONCE(ret);
 272         if (!ret)
 273                 event->registered = 1;
 274 }
 275
 276 static
 277 void register_trigger(struct lttng_trigger *trigger)
 278 {
 279         int ret;
 280         const struct lttng_event_desc *desc;
 281
 282         assert(trigger->registered == 0);
 283         desc = trigger->desc;
 284         ret = __tracepoint_probe_register_queue_release(desc->name,
 285                 desc->u.ext.trigger_callback, trigger, desc->signature);
 286         WARN_ON_ONCE(ret);
 287         if (!ret)
 288                 trigger->registered = 1;
 289 }
 290
 291 static
 292 void unregister_event(struct lttng_event *event)
 293 {
 294         int ret;
 295         const struct lttng_event_desc *desc;
 296
 297         assert(event->registered == 1);
 298         desc = event->desc;
 299         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 300                         desc->probe_callback,
 301                         event);
 302         WARN_ON_ONCE(ret);
 303         if (!ret)
 304                 event->registered = 0;
 305 }
 306
 307 static
 308 void unregister_trigger(struct lttng_trigger *trigger)
 309 {
 310         int ret;
 311         const struct lttng_event_desc *desc;
 312
 313         assert(trigger->registered == 1);
 314         desc = trigger->desc;
 315         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 316                 desc->u.ext.trigger_callback, trigger);
 317         WARN_ON_ONCE(ret);
 318         if (!ret)
 319                 trigger->registered = 0;
 320 }
 321
 322 /*
 323  * Only used internally at session destruction.
 324  */
 325 static
 326 void _lttng_event_unregister(struct lttng_event *event)
 327 {
 328         if (event->registered)
 329                 unregister_event(event);
 330 }
 331
 332 /*
 333  * Only used internally at session destruction.
 334  */
 335 static
 336 void _lttng_trigger_unregister(struct lttng_trigger *trigger)
 337 {
 338         if (trigger->registered)
 339                 unregister_trigger(trigger);
 340 }
 341
 342 void lttng_session_destroy(struct lttng_session *session)
 343 {
 344         struct lttng_channel *chan, *tmpchan;
 345         struct lttng_event *event, *tmpevent;
 346         struct lttng_enum *_enum, *tmp_enum;
 347         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 348
 349         CMM_ACCESS_ONCE(session->active) = 0;
 350         cds_list_for_each_entry(event, &session->events_head, node) {
 351                 _lttng_event_unregister(event);
 352         }
 353         synchronize_trace();    /* Wait for in-flight events to complete */
 354         __tracepoint_probe_prune_release_queue();
 355         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 356                         &session->enablers_head, node)
 357                 lttng_event_enabler_destroy(event_enabler);
 358         cds_list_for_each_entry_safe(event, tmpevent,
 359                         &session->events_head, node)
 360                 _lttng_event_destroy(event);
 361         cds_list_for_each_entry_safe(_enum, tmp_enum,
 362                         &session->enums_head, node)
 363                 _lttng_enum_destroy(_enum);
 364         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 365                 _lttng_channel_unmap(chan);
 366         cds_list_del(&session->node);
 367         lttng_destroy_context(session->ctx);
 368         free(session);
 369 }
 370
 371 void lttng_trigger_group_destroy(
 372                 struct lttng_trigger_group *trigger_group)
 373 {
 374         int close_ret;
 375         struct lttng_trigger_enabler *trigger_enabler, *tmptrigger_enabler;
 376         struct lttng_trigger *trigger, *tmptrigger;
 377
 378         if (!trigger_group) {
 379                 return;
 380         }
 381
 382         cds_list_for_each_entry(trigger, &trigger_group->triggers_head, node)
 383                 _lttng_trigger_unregister(trigger);
 384
 385         synchronize_trace();
 386
 387         cds_list_for_each_entry_safe(trigger_enabler, tmptrigger_enabler,
 388                         &trigger_group->enablers_head, node)
 389                 lttng_trigger_enabler_destroy(trigger_enabler);
 390
 391         cds_list_for_each_entry_safe(trigger, tmptrigger,
 392                         &trigger_group->triggers_head, node)
 393                 _lttng_trigger_destroy(trigger);
 394
 395         if (trigger_group->error_counter)
 396                 lttng_ust_counter_destroy(trigger_group->error_counter);
 397
 398         /* Close the notification fd to the listener of triggers. */
 399
 400         lttng_ust_lock_fd_tracker();
 401         close_ret = close(trigger_group->notification_fd);
 402         if (!close_ret) {
 403                 lttng_ust_delete_fd_from_tracker(trigger_group->notification_fd);
 404         } else {
 405                 PERROR("close");
 406                 abort();
 407         }
 408         lttng_ust_unlock_fd_tracker();
 409
 410         cds_list_del(&trigger_group->node);
 411
 412         free(trigger_group);
 413 }
 414
 415 static
 416 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 417 {
 418         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 419         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 420
 421         if (!enabler) {
 422                 return;
 423         }
 424
 425         /* Destroy filter bytecode */
 426         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 427                         &enabler->filter_bytecode_head, node) {
 428                 free(filter_node);
 429         }
 430
 431         /* Destroy excluders */
 432         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 433                         &enabler->excluder_head, node) {
 434                 free(excluder_node);
 435         }
 436 }
 437
 438  void lttng_trigger_enabler_destroy(struct lttng_trigger_enabler *trigger_enabler)
 439 {
 440         if (!trigger_enabler) {
 441                 return;
 442         }
 443
 444         cds_list_del(&trigger_enabler->node);
 445
 446         lttng_enabler_destroy(lttng_trigger_enabler_as_enabler(trigger_enabler));
 447
 448         free(trigger_enabler);
 449 }
 450
 451 static
 452 int lttng_enum_create(const struct lttng_enum_desc *desc,
 453                 struct lttng_session *session)
 454 {
 455         const char *enum_name = desc->name;
 456         struct lttng_enum *_enum;
 457         struct cds_hlist_head *head;
 458         int ret = 0;
 459         size_t name_len = strlen(enum_name);
 460         uint32_t hash;
 461         int notify_socket;
 462
 463         /* Check if this enum is already registered for this session. */
 464         hash = jhash(enum_name, name_len, 0);
 465         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 466
 467         _enum = lttng_ust_enum_get_from_desc(session, desc);
 468         if (_enum) {
 469                 ret = -EEXIST;
 470                 goto exist;
 471         }
 472
 473         notify_socket = lttng_get_notify_socket(session->owner);
 474         if (notify_socket < 0) {
 475                 ret = notify_socket;
 476                 goto socket_error;
 477         }
 478
 479         _enum = zmalloc(sizeof(*_enum));
 480         if (!_enum) {
 481                 ret = -ENOMEM;
 482                 goto cache_error;
 483         }
 484         _enum->session = session;
 485         _enum->desc = desc;
 486
 487         ret = ustcomm_register_enum(notify_socket,
 488                 session->objd,
 489                 enum_name,
 490                 desc->nr_entries,
 491                 desc->entries,
 492                 &_enum->id);
 493         if (ret < 0) {
 494                 DBG("Error (%d) registering enumeration to sessiond", ret);
 495                 goto sessiond_register_error;
 496         }
 497         cds_list_add(&_enum->node, &session->enums_head);
 498         cds_hlist_add_head(&_enum->hlist, head);
 499         return 0;
 500
 501 sessiond_register_error:
 502         free(_enum);
 503 cache_error:
 504 socket_error:
 505 exist:
 506         return ret;
 507 }
 508
 509 static
 510 int lttng_create_enum_check(const struct lttng_type *type,
 511                 struct lttng_session *session)
 512 {
 513         switch (type->atype) {
 514         case atype_enum:
 515         {
 516                 const struct lttng_enum_desc *enum_desc;
 517                 int ret;
 518
 519                 enum_desc = type->u.legacy.basic.enumeration.desc;
 520                 ret = lttng_enum_create(enum_desc, session);
 521                 if (ret && ret != -EEXIST) {
 522                         DBG("Unable to create enum error: (%d)", ret);
 523                         return ret;
 524                 }
 525                 break;
 526         }
 527         case atype_enum_nestable:
 528         {
 529                 const struct lttng_enum_desc *enum_desc;
 530                 int ret;
 531
 532                 enum_desc = type->u.enum_nestable.desc;
 533                 ret = lttng_enum_create(enum_desc, session);
 534                 if (ret && ret != -EEXIST) {
 535                         DBG("Unable to create enum error: (%d)", ret);
 536                         return ret;
 537                 }
 538                 break;
 539         }
 540         case atype_dynamic:
 541         {
 542                 const struct lttng_event_field *tag_field_generic;
 543                 const struct lttng_enum_desc *enum_desc;
 544                 int ret;
 545
 546                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 547                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 548                 ret = lttng_enum_create(enum_desc, session);
 549                 if (ret && ret != -EEXIST) {
 550                         DBG("Unable to create enum error: (%d)", ret);
 551                         return ret;
 552                 }
 553                 break;
 554         }
 555         default:
 556                 /* TODO: nested types when they become supported. */
 557                 break;
 558         }
 559         return 0;
 560 }
 561
 562 static
 563 int lttng_create_all_event_enums(size_t nr_fields,
 564                 const struct lttng_event_field *event_fields,
 565                 struct lttng_session *session)
 566 {
 567         size_t i;
 568         int ret;
 569
 570         /* For each field, ensure enum is part of the session. */
 571         for (i = 0; i < nr_fields; i++) {
 572                 const struct lttng_type *type = &event_fields[i].type;
 573
 574                 ret = lttng_create_enum_check(type, session);
 575                 if (ret)
 576                         return ret;
 577         }
 578         return 0;
 579 }
 580
 581 static
 582 int lttng_create_all_ctx_enums(size_t nr_fields,
 583                 const struct lttng_ctx_field *ctx_fields,
 584                 struct lttng_session *session)
 585 {
 586         size_t i;
 587         int ret;
 588
 589         /* For each field, ensure enum is part of the session. */
 590         for (i = 0; i < nr_fields; i++) {
 591                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 592
 593                 ret = lttng_create_enum_check(type, session);
 594                 if (ret)
 595                         return ret;
 596         }
 597         return 0;
 598 }
 599
 600 /*
 601  * Ensure that a state-dump will be performed for this session at the end
 602  * of the current handle_message().
 603  */
 604 int lttng_session_statedump(struct lttng_session *session)
 605 {
 606         session->statedump_pending = 1;
 607         lttng_ust_sockinfo_session_enabled(session->owner);
 608         return 0;
 609 }
 610
 611 int lttng_session_enable(struct lttng_session *session)
 612 {
 613         int ret = 0;
 614         struct lttng_channel *chan;
 615         int notify_socket;
 616
 617         if (session->active) {
 618                 ret = -EBUSY;
 619                 goto end;
 620         }
 621
 622         notify_socket = lttng_get_notify_socket(session->owner);
 623         if (notify_socket < 0)
 624                 return notify_socket;
 625
 626         /* Set transient enabler state to "enabled" */
 627         session->tstate = 1;
 628
 629         /* We need to sync enablers with session before activation. */
 630         lttng_session_sync_event_enablers(session);
 631
 632         /*
 633          * Snapshot the number of events per channel to know the type of header
 634          * we need to use.
 635          */
 636         cds_list_for_each_entry(chan, &session->chan_head, node) {
 637                 const struct lttng_ctx *ctx;
 638                 const struct lttng_ctx_field *fields = NULL;
 639                 size_t nr_fields = 0;
 640                 uint32_t chan_id;
 641
 642                 /* don't change it if session stop/restart */
 643                 if (chan->header_type)
 644                         continue;
 645                 ctx = chan->ctx;
 646                 if (ctx) {
 647                         nr_fields = ctx->nr_fields;
 648                         fields = ctx->fields;
 649                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 650                                 session);
 651                         if (ret < 0) {
 652                                 DBG("Error (%d) adding enum to session", ret);
 653                                 return ret;
 654                         }
 655                 }
 656                 ret = ustcomm_register_channel(notify_socket,
 657                         session,
 658                         session->objd,
 659                         chan->objd,
 660                         nr_fields,
 661                         fields,
 662                         &chan_id,
 663                         &chan->header_type);
 664                 if (ret) {
 665                         DBG("Error (%d) registering channel to sessiond", ret);
 666                         return ret;
 667                 }
 668                 if (chan_id != chan->id) {
 669                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 670                                 chan_id, chan->id);
 671                         return -EINVAL;
 672                 }
 673         }
 674
 675         /* Set atomically the state to "active" */
 676         CMM_ACCESS_ONCE(session->active) = 1;
 677         CMM_ACCESS_ONCE(session->been_active) = 1;
 678
 679         ret = lttng_session_statedump(session);
 680         if (ret)
 681                 return ret;
 682 end:
 683         return ret;
 684 }
 685
 686 int lttng_session_disable(struct lttng_session *session)
 687 {
 688         int ret = 0;
 689
 690         if (!session->active) {
 691                 ret = -EBUSY;
 692                 goto end;
 693         }
 694         /* Set atomically the state to "inactive" */
 695         CMM_ACCESS_ONCE(session->active) = 0;
 696
 697         /* Set transient enabler state to "disabled" */
 698         session->tstate = 0;
 699         lttng_session_sync_event_enablers(session);
 700 end:
 701         return ret;
 702 }
 703
 704 int lttng_channel_enable(struct lttng_channel *channel)
 705 {
 706         int ret = 0;
 707
 708         if (channel->enabled) {
 709                 ret = -EBUSY;
 710                 goto end;
 711         }
 712         /* Set transient enabler state to "enabled" */
 713         channel->tstate = 1;
 714         lttng_session_sync_event_enablers(channel->session);
 715         /* Set atomically the state to "enabled" */
 716         CMM_ACCESS_ONCE(channel->enabled) = 1;
 717 end:
 718         return ret;
 719 }
 720
 721 int lttng_channel_disable(struct lttng_channel *channel)
 722 {
 723         int ret = 0;
 724
 725         if (!channel->enabled) {
 726                 ret = -EBUSY;
 727                 goto end;
 728         }
 729         /* Set atomically the state to "disabled" */
 730         CMM_ACCESS_ONCE(channel->enabled) = 0;
 731         /* Set transient enabler state to "enabled" */
 732         channel->tstate = 0;
 733         lttng_session_sync_event_enablers(channel->session);
 734 end:
 735         return ret;
 736 }
 737
 738 static inline
 739 struct cds_hlist_head *borrow_hash_table_bucket(
 740                 struct cds_hlist_head *hash_table,
 741                 unsigned int hash_table_size,
 742                 const struct lttng_event_desc *desc)
 743 {
 744         const char *event_name;
 745         size_t name_len;
 746         uint32_t hash;
 747
 748         event_name = desc->name;
 749         name_len = strlen(event_name);
 750
 751         hash = jhash(event_name, name_len, 0);
 752         return &hash_table[hash & (hash_table_size - 1)];
 753 }
 754
 755 /*
 756  * Supports event creation while tracing session is active.
 757  */
 758 static
 759 int lttng_event_create(const struct lttng_event_desc *desc,
 760                 struct lttng_channel *chan)
 761 {
 762         struct lttng_event *event;
 763         struct lttng_session *session = chan->session;
 764         struct cds_hlist_head *head;
 765         int ret = 0;
 766         int notify_socket, loglevel;
 767         const char *uri;
 768
 769         head = borrow_hash_table_bucket(chan->session->events_ht.table,
 770                 LTTNG_UST_EVENT_HT_SIZE, desc);
 771
 772         notify_socket = lttng_get_notify_socket(session->owner);
 773         if (notify_socket < 0) {
 774                 ret = notify_socket;
 775                 goto socket_error;
 776         }
 777
 778         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 779                         session);
 780         if (ret < 0) {
 781                 DBG("Error (%d) adding enum to session", ret);
 782                 goto create_enum_error;
 783         }
 784
 785         /*
 786          * Check if loglevel match. Refuse to connect event if not.
 787          */
 788         event = zmalloc(sizeof(struct lttng_event));
 789         if (!event) {
 790                 ret = -ENOMEM;
 791                 goto cache_error;
 792         }
 793         event->chan = chan;
 794
 795         /* Event will be enabled by enabler sync. */
 796         event->enabled = 0;
 797         event->registered = 0;
 798         CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
 799         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 800         event->desc = desc;
 801
 802         if (desc->loglevel)
 803                 loglevel = *(*event->desc->loglevel);
 804         else
 805                 loglevel = TRACE_DEFAULT;
 806         if (desc->u.ext.model_emf_uri)
 807                 uri = *(desc->u.ext.model_emf_uri);
 808         else
 809                 uri = NULL;
 810
 811         /* Fetch event ID from sessiond */
 812         ret = ustcomm_register_event(notify_socket,
 813                 session,
 814                 session->objd,
 815                 chan->objd,
 816                 desc->name,
 817                 loglevel,
 818                 desc->signature,
 819                 desc->nr_fields,
 820                 desc->fields,
 821                 uri,
 822                 &event->id);
 823         if (ret < 0) {
 824                 DBG("Error (%d) registering event to sessiond", ret);
 825                 goto sessiond_register_error;
 826         }
 827
 828         cds_list_add(&event->node, &chan->session->events_head);
 829         cds_hlist_add_head(&event->hlist, head);
 830         return 0;
 831
 832 sessiond_register_error:
 833         free(event);
 834 cache_error:
 835 create_enum_error:
 836 socket_error:
 837         return ret;
 838 }
 839
 840 static
 841 int lttng_trigger_create(const struct lttng_event_desc *desc,
 842                 uint64_t id, uint64_t error_counter_index,
 843                 struct lttng_trigger_group *trigger_group)
 844 {
 845         struct lttng_trigger *trigger;
 846         struct cds_hlist_head *head;
 847         int ret = 0;
 848
 849         /*
 850          * Get the hashtable bucket the created lttng_trigger object should be
 851          * inserted.
 852          */
 853         head = borrow_hash_table_bucket(trigger_group->triggers_ht.table,
 854                 LTTNG_UST_TRIGGER_HT_SIZE, desc);
 855
 856         trigger = zmalloc(sizeof(struct lttng_trigger));
 857         if (!trigger) {
 858                 ret = -ENOMEM;
 859                 goto error;
 860         }
 861
 862         trigger->group = trigger_group;
 863         trigger->id = id;
 864         trigger->error_counter_index = error_counter_index;
 865
 866         /* Trigger will be enabled by enabler sync. */
 867         trigger->enabled = 0;
 868         trigger->registered = 0;
 869
 870         CDS_INIT_LIST_HEAD(&trigger->filter_bytecode_runtime_head);
 871         CDS_INIT_LIST_HEAD(&trigger->capture_bytecode_runtime_head);
 872         CDS_INIT_LIST_HEAD(&trigger->enablers_ref_head);
 873         trigger->desc = desc;
 874
 875         cds_list_add(&trigger->node, &trigger_group->triggers_head);
 876         cds_hlist_add_head(&trigger->hlist, head);
 877
 878         return 0;
 879
 880 error:
 881         return ret;
 882 }
 883
 884 static
 885 void _lttng_trigger_destroy(struct lttng_trigger *trigger)
 886 {
 887         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 888
 889         /* Remove from trigger list. */
 890         cds_list_del(&trigger->node);
 891         /* Remove from trigger hash table. */
 892         cds_hlist_del(&trigger->hlist);
 893
 894         lttng_free_trigger_filter_runtime(trigger);
 895
 896         /* Free trigger enabler refs */
 897         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 898                         &trigger->enablers_ref_head, node)
 899                 free(enabler_ref);
 900         free(trigger);
 901 }
 902
 903 static
 904 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 905                 struct lttng_enabler *enabler)
 906 {
 907         int loglevel = 0;
 908         unsigned int has_loglevel = 0;
 909
 910         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 911         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 912                         desc->name, SIZE_MAX))
 913                 return 0;
 914         if (desc->loglevel) {
 915                 loglevel = *(*desc->loglevel);
 916                 has_loglevel = 1;
 917         }
 918         if (!lttng_loglevel_match(loglevel,
 919                         has_loglevel,
 920                         enabler->event_param.loglevel_type,
 921                         enabler->event_param.loglevel))
 922                 return 0;
 923         return 1;
 924 }
 925
 926 static
 927 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 928                 struct lttng_enabler *enabler)
 929 {
 930         int loglevel = 0;
 931         unsigned int has_loglevel = 0;
 932
 933         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 934         if (strcmp(desc->name, enabler->event_param.name))
 935                 return 0;
 936         if (desc->loglevel) {
 937                 loglevel = *(*desc->loglevel);
 938                 has_loglevel = 1;
 939         }
 940         if (!lttng_loglevel_match(loglevel,
 941                         has_loglevel,
 942                         enabler->event_param.loglevel_type,
 943                         enabler->event_param.loglevel))
 944                 return 0;
 945         return 1;
 946 }
 947
 948 static
 949 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 950                 struct lttng_enabler *enabler)
 951 {
 952         switch (enabler->format_type) {
 953         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 954         {
 955                 struct lttng_ust_excluder_node *excluder;
 956
 957                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 958                         return 0;
 959                 }
 960
 961                 /*
 962                  * If the matching event matches with an excluder,
 963                  * return 'does not match'
 964                  */
 965                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 966                         int count;
 967
 968                         for (count = 0; count < excluder->excluder.count; count++) {
 969                                 int len;
 970                                 char *excluder_name;
 971
 972                                 excluder_name = (char *) (excluder->excluder.names)
 973                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 974                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 975                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 976                                         return 0;
 977                         }
 978                 }
 979                 return 1;
 980         }
 981         case LTTNG_ENABLER_FORMAT_EVENT:
 982                 return lttng_desc_match_event_enabler(desc, enabler);
 983         default:
 984                 return -EINVAL;
 985         }
 986 }
 987
 988 static
 989 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 990                 struct lttng_event *event)
 991 {
 992         if (lttng_desc_match_enabler(event->desc,
 993                         lttng_event_enabler_as_enabler(event_enabler))
 994                         && event->chan == event_enabler->chan)
 995                 return 1;
 996         else
 997                 return 0;
 998 }
 999
1000 static
1001 int lttng_trigger_enabler_match_trigger(
1002                 struct lttng_trigger_enabler *trigger_enabler,
1003                 struct lttng_trigger *trigger)
1004 {
1005         int desc_matches = lttng_desc_match_enabler(trigger->desc,
1006                 lttng_trigger_enabler_as_enabler(trigger_enabler));
1007
1008         if (desc_matches && trigger->group == trigger_enabler->group &&
1009                         trigger->id == trigger_enabler->id)
1010                 return 1;
1011         else
1012                 return 0;
1013 }
1014
1015 static
1016 struct lttng_enabler_ref *lttng_enabler_ref(
1017                 struct cds_list_head *enabler_ref_list,
1018                 struct lttng_enabler *enabler)
1019 {
1020         struct lttng_enabler_ref *enabler_ref;
1021
1022         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1023                 if (enabler_ref->ref == enabler)
1024                         return enabler_ref;
1025         }
1026         return NULL;
1027 }
1028
1029 /*
1030  * Create struct lttng_event if it is missing and present in the list of
1031  * tracepoint probes.
1032  */
1033 static
1034 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1035 {
1036         struct lttng_session *session = event_enabler->chan->session;
1037         struct lttng_probe_desc *probe_desc;
1038         const struct lttng_event_desc *desc;
1039         struct lttng_event *event;
1040         int i;
1041         struct cds_list_head *probe_list;
1042
1043         probe_list = lttng_get_probe_list_head();
1044         /*
1045          * For each probe event, if we find that a probe event matches
1046          * our enabler, create an associated lttng_event if not
1047          * already present.
1048          */
1049         cds_list_for_each_entry(probe_desc, probe_list, head) {
1050                 for (i = 0; i < probe_desc->nr_events; i++) {
1051                         int ret;
1052                         bool found = false;
1053                         struct cds_hlist_head *head;
1054                         struct cds_hlist_node *node;
1055
1056                         desc = probe_desc->event_desc[i];
1057                         if (!lttng_desc_match_enabler(desc,
1058                                         lttng_event_enabler_as_enabler(event_enabler)))
1059                                 continue;
1060
1061                         head = borrow_hash_table_bucket(
1062                                 session->events_ht.table,
1063                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1064
1065                         cds_hlist_for_each_entry(event, node, head, hlist) {
1066                                 if (event->desc == desc
1067                                                 && event->chan == event_enabler->chan) {
1068                                         found = true;
1069                                         break;
1070                                 }
1071                         }
1072                         if (found)
1073                                 continue;
1074
1075                         /*
1076                          * We need to create an event for this
1077                          * event probe.
1078                          */
1079                         ret = lttng_event_create(probe_desc->event_desc[i],
1080                                         event_enabler->chan);
1081                         if (ret) {
1082                                 DBG("Unable to create event %s, error %d\n",
1083                                         probe_desc->event_desc[i]->name, ret);
1084                         }
1085                 }
1086         }
1087 }
1088
1089 static
1090 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1091                 void (*event_func)(struct lttng_session *session,
1092                         struct lttng_event *event),
1093                 void (*trigger_func)(struct lttng_trigger *trigger))
1094 {
1095         struct cds_hlist_node *node, *tmp_node;
1096         struct cds_list_head *sessionsp;
1097         unsigned int i;
1098
1099         /* Get handle on list of sessions. */
1100         sessionsp = _lttng_get_sessions();
1101
1102         /*
1103          * Iterate over all events in the probe provider descriptions and
1104          * sessions to queue the unregistration of the events.
1105          */
1106         for (i = 0; i < provider_desc->nr_events; i++) {
1107                 const struct lttng_event_desc *event_desc;
1108                 struct lttng_trigger_group *trigger_group;
1109                 struct lttng_trigger *trigger;
1110                 struct lttng_session *session;
1111                 struct cds_hlist_head *head;
1112                 struct lttng_event *event;
1113
1114                 event_desc = provider_desc->event_desc[i];
1115
1116                 /*
1117                  * Iterate over all session to find the current event
1118                  * description.
1119                  */
1120                 cds_list_for_each_entry(session, sessionsp, node) {
1121                         /*
1122                          * Get the list of events in the hashtable bucket and
1123                          * iterate to find the event matching this descriptor.
1124                          */
1125                         head = borrow_hash_table_bucket(
1126                                 session->events_ht.table,
1127                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1128
1129                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1130                                 if (event_desc == event->desc) {
1131                                         event_func(session, event);
1132                                         break;
1133                                 }
1134                         }
1135                 }
1136
1137                 /*
1138                  * Iterate over all trigger groups to find the current event
1139                  * description.
1140                  */
1141                 cds_list_for_each_entry(trigger_group, &trigger_groups, node) {
1142                         /*
1143                          * Get the list of triggers in the hashtable bucket and
1144                          * iterate to find the trigger matching this
1145                          * descriptor.
1146                          */
1147                         head = borrow_hash_table_bucket(
1148                                 trigger_group->triggers_ht.table,
1149                                 LTTNG_UST_TRIGGER_HT_SIZE, event_desc);
1150
1151                         cds_hlist_for_each_entry_safe(trigger, node, tmp_node, head, hlist) {
1152                                 if (event_desc == trigger->desc) {
1153                                         trigger_func(trigger);
1154                                         break;
1155                                 }
1156                         }
1157                 }
1158         }
1159 }
1160
1161 static
1162 void _unregister_event(struct lttng_session *session,
1163                 struct lttng_event *event)
1164 {
1165         _lttng_event_unregister(event);
1166 }
1167
1168 static
1169 void _event_enum_destroy(struct lttng_session *session,
1170                 struct lttng_event *event)
1171 {
1172         unsigned int i;
1173
1174         /* Destroy enums of the current event. */
1175         for (i = 0; i < event->desc->nr_fields; i++) {
1176                 const struct lttng_enum_desc *enum_desc;
1177                 const struct lttng_event_field *field;
1178                 struct lttng_enum *curr_enum;
1179
1180                 field = &(event->desc->fields[i]);
1181                 switch (field->type.atype) {
1182                 case atype_enum:
1183                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1184                         break;
1185                 case atype_enum_nestable:
1186                         enum_desc = field->type.u.enum_nestable.desc;
1187                         break;
1188                 default:
1189                         continue;
1190                 }
1191
1192                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1193                 if (curr_enum) {
1194                         _lttng_enum_destroy(curr_enum);
1195                 }
1196         }
1197
1198         /* Destroy event. */
1199         _lttng_event_destroy(event);
1200 }
1201
1202 /*
1203  * Iterate over all the UST sessions to unregister and destroy all probes from
1204  * the probe provider descriptor received as argument. Must me called with the
1205  * ust_lock held.
1206  */
1207 void lttng_probe_provider_unregister_events(
1208                 struct lttng_probe_desc *provider_desc)
1209 {
1210         /*
1211          * Iterate over all events in the probe provider descriptions and sessions
1212          * to queue the unregistration of the events.
1213          */
1214         probe_provider_event_for_each(provider_desc, _unregister_event,
1215                 _lttng_trigger_unregister);
1216
1217         /* Wait for grace period. */
1218         synchronize_trace();
1219         /* Prune the unregistration queue. */
1220         __tracepoint_probe_prune_release_queue();
1221
1222         /*
1223          * It is now safe to destroy the events and remove them from the event list
1224          * and hashtables.
1225          */
1226         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1227                 _lttng_trigger_destroy);
1228 }
1229
1230 /*
1231  * Create events associated with an event enabler (if not already present),
1232  * and add backward reference from the event to the enabler.
1233  */
1234 static
1235 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1236 {
1237         struct lttng_session *session = event_enabler->chan->session;
1238         struct lttng_event *event;
1239
1240         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1241                 goto end;
1242
1243         /* First ensure that probe events are created for this enabler. */
1244         lttng_create_event_if_missing(event_enabler);
1245
1246         /* For each event matching enabler in session event list. */
1247         cds_list_for_each_entry(event, &session->events_head, node) {
1248                 struct lttng_enabler_ref *enabler_ref;
1249
1250                 if (!lttng_event_enabler_match_event(event_enabler, event))
1251                         continue;
1252
1253                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1254                         lttng_event_enabler_as_enabler(event_enabler));
1255                 if (!enabler_ref) {
1256                         /*
1257                          * If no backward ref, create it.
1258                          * Add backward ref from event to enabler.
1259                          */
1260                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1261                         if (!enabler_ref)
1262                                 return -ENOMEM;
1263                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1264                                 event_enabler);
1265                         cds_list_add(&enabler_ref->node,
1266                                 &event->enablers_ref_head);
1267                 }
1268
1269                 /*
1270                  * Link filter bytecodes if not linked yet.
1271                  */
1272                 lttng_enabler_link_bytecode(event->desc,
1273                         &session->ctx,
1274                         &event->filter_bytecode_runtime_head,
1275                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1276
1277                 /* TODO: merge event context. */
1278         }
1279 end:
1280         return 0;
1281 }
1282
1283 /*
1284  * Called at library load: connect the probe on all enablers matching
1285  * this event.
1286  * Called with session mutex held.
1287  */
1288 int lttng_fix_pending_events(void)
1289 {
1290         struct lttng_session *session;
1291
1292         cds_list_for_each_entry(session, &sessions, node) {
1293                 lttng_session_lazy_sync_event_enablers(session);
1294         }
1295         return 0;
1296 }
1297
1298 int lttng_fix_pending_triggers(void)
1299 {
1300         struct lttng_trigger_group *trigger_group;
1301
1302         cds_list_for_each_entry(trigger_group, &trigger_groups, node) {
1303                 lttng_trigger_group_sync_enablers(trigger_group);
1304         }
1305         return 0;
1306 }
1307
1308 /*
1309  * For each session of the owner thread, execute pending statedump.
1310  * Only dump state for the sessions owned by the caller thread, because
1311  * we don't keep ust_lock across the entire iteration.
1312  */
1313 void lttng_handle_pending_statedump(void *owner)
1314 {
1315         struct lttng_session *session;
1316
1317         /* Execute state dump */
1318         do_lttng_ust_statedump(owner);
1319
1320         /* Clear pending state dump */
1321         if (ust_lock()) {
1322                 goto end;
1323         }
1324         cds_list_for_each_entry(session, &sessions, node) {
1325                 if (session->owner != owner)
1326                         continue;
1327                 if (!session->statedump_pending)
1328                         continue;
1329                 session->statedump_pending = 0;
1330         }
1331 end:
1332         ust_unlock();
1333         return;
1334 }
1335
1336 /*
1337  * Only used internally at session destruction.
1338  */
1339 static
1340 void _lttng_event_destroy(struct lttng_event *event)
1341 {
1342         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1343
1344         /* Remove from event list. */
1345         cds_list_del(&event->node);
1346         /* Remove from event hash table. */
1347         cds_hlist_del(&event->hlist);
1348
1349         lttng_destroy_context(event->ctx);
1350         lttng_free_event_filter_runtime(event);
1351         /* Free event enabler refs */
1352         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1353                         &event->enablers_ref_head, node)
1354                 free(enabler_ref);
1355         free(event);
1356 }
1357
1358 static
1359 void _lttng_enum_destroy(struct lttng_enum *_enum)
1360 {
1361         cds_list_del(&_enum->node);
1362         cds_hlist_del(&_enum->hlist);
1363         free(_enum);
1364 }
1365
1366 void lttng_ust_events_exit(void)
1367 {
1368         struct lttng_session *session, *tmpsession;
1369
1370         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1371                 lttng_session_destroy(session);
1372 }
1373
1374 /*
1375  * Enabler management.
1376  */
1377 struct lttng_event_enabler *lttng_event_enabler_create(
1378                 enum lttng_enabler_format_type format_type,
1379                 struct lttng_ust_event *event_param,
1380                 struct lttng_channel *chan)
1381 {
1382         struct lttng_event_enabler *event_enabler;
1383
1384         event_enabler = zmalloc(sizeof(*event_enabler));
1385         if (!event_enabler)
1386                 return NULL;
1387         event_enabler->base.format_type = format_type;
1388         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1389         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1390         memcpy(&event_enabler->base.event_param, event_param,
1391                 sizeof(event_enabler->base.event_param));
1392         event_enabler->chan = chan;
1393         /* ctx left NULL */
1394         event_enabler->base.enabled = 0;
1395         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1396         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1397
1398         return event_enabler;
1399 }
1400
1401 struct lttng_trigger_enabler *lttng_trigger_enabler_create(
1402                 struct lttng_trigger_group *trigger_group,
1403                 enum lttng_enabler_format_type format_type,
1404                 struct lttng_ust_trigger *trigger_param)
1405 {
1406         struct lttng_trigger_enabler *trigger_enabler;
1407
1408         trigger_enabler = zmalloc(sizeof(*trigger_enabler));
1409         if (!trigger_enabler)
1410                 return NULL;
1411         trigger_enabler->base.format_type = format_type;
1412         CDS_INIT_LIST_HEAD(&trigger_enabler->base.filter_bytecode_head);
1413         CDS_INIT_LIST_HEAD(&trigger_enabler->capture_bytecode_head);
1414         CDS_INIT_LIST_HEAD(&trigger_enabler->base.excluder_head);
1415
1416         trigger_enabler->id = trigger_param->id;
1417         trigger_enabler->num_captures = 0;
1418
1419         memcpy(&trigger_enabler->base.event_param.name, trigger_param->name,
1420                 sizeof(trigger_enabler->base.event_param.name));
1421         trigger_enabler->base.event_param.instrumentation = trigger_param->instrumentation;
1422         trigger_enabler->base.event_param.loglevel = trigger_param->loglevel;
1423         trigger_enabler->base.event_param.loglevel_type = trigger_param->loglevel_type;
1424
1425         trigger_enabler->base.enabled = 0;
1426         trigger_enabler->group = trigger_group;
1427
1428         cds_list_add(&trigger_enabler->node, &trigger_group->enablers_head);
1429
1430         lttng_trigger_group_sync_enablers(trigger_group);
1431
1432         return trigger_enabler;
1433 }
1434
1435 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1436 {
1437         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1438         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1439
1440         return 0;
1441 }
1442
1443 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1444 {
1445         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1446         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1447
1448         return 0;
1449 }
1450
1451 static
1452 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1453                 struct lttng_ust_bytecode_node *bytecode)
1454 {
1455         bytecode->enabler = enabler;
1456         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
1457 }
1458
1459 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1460                 struct lttng_ust_bytecode_node *bytecode)
1461 {
1462         _lttng_enabler_attach_filter_bytecode(
1463                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1464
1465         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1466         return 0;
1467 }
1468
1469 static
1470 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1471                 struct lttng_ust_excluder_node *excluder)
1472 {
1473         excluder->enabler = enabler;
1474         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
1475 }
1476
1477 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1478                 struct lttng_ust_excluder_node *excluder)
1479 {
1480         _lttng_enabler_attach_exclusion(
1481                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1482
1483         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1484         return 0;
1485 }
1486
1487 int lttng_trigger_enabler_enable(struct lttng_trigger_enabler *trigger_enabler)
1488 {
1489         lttng_trigger_enabler_as_enabler(trigger_enabler)->enabled = 1;
1490         lttng_trigger_group_sync_enablers(trigger_enabler->group);
1491
1492         return 0;
1493 }
1494
1495 int lttng_trigger_enabler_disable(struct lttng_trigger_enabler *trigger_enabler)
1496 {
1497         lttng_trigger_enabler_as_enabler(trigger_enabler)->enabled = 0;
1498         lttng_trigger_group_sync_enablers(trigger_enabler->group);
1499
1500         return 0;
1501 }
1502
1503 int lttng_trigger_enabler_attach_filter_bytecode(
1504                 struct lttng_trigger_enabler *trigger_enabler,
1505                 struct lttng_ust_bytecode_node *bytecode)
1506 {
1507         _lttng_enabler_attach_filter_bytecode(
1508                 lttng_trigger_enabler_as_enabler(trigger_enabler), bytecode);
1509
1510         lttng_trigger_group_sync_enablers(trigger_enabler->group);
1511         return 0;
1512 }
1513
1514 int lttng_trigger_enabler_attach_capture_bytecode(
1515                 struct lttng_trigger_enabler *trigger_enabler,
1516                 struct lttng_ust_bytecode_node *bytecode)
1517 {
1518         bytecode->enabler = lttng_trigger_enabler_as_enabler(trigger_enabler);
1519         cds_list_add_tail(&bytecode->node, &trigger_enabler->capture_bytecode_head);
1520         trigger_enabler->num_captures++;
1521
1522         lttng_trigger_group_sync_enablers(trigger_enabler->group);
1523         return 0;
1524 }
1525
1526 int lttng_trigger_enabler_attach_exclusion(
1527                 struct lttng_trigger_enabler *trigger_enabler,
1528                 struct lttng_ust_excluder_node *excluder)
1529 {
1530         _lttng_enabler_attach_exclusion(
1531                 lttng_trigger_enabler_as_enabler(trigger_enabler), excluder);
1532
1533         lttng_trigger_group_sync_enablers(trigger_enabler->group);
1534         return 0;
1535 }
1536
1537 int lttng_attach_context(struct lttng_ust_context *context_param,
1538                 union ust_args *uargs,
1539                 struct lttng_ctx **ctx, struct lttng_session *session)
1540 {
1541         /*
1542          * We cannot attach a context after trace has been started for a
1543          * session because the metadata does not allow expressing this
1544          * information outside of the original channel scope.
1545          */
1546         if (session->been_active)
1547                 return -EPERM;
1548
1549         switch (context_param->ctx) {
1550         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1551                 return lttng_add_pthread_id_to_ctx(ctx);
1552         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1553         {
1554                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1555
1556                 perf_ctx_param = &context_param->u.perf_counter;
1557                 return lttng_add_perf_counter_to_ctx(
1558                         perf_ctx_param->type,
1559                         perf_ctx_param->config,
1560                         perf_ctx_param->name,
1561                         ctx);
1562         }
1563         case LTTNG_UST_CONTEXT_VTID:
1564                 return lttng_add_vtid_to_ctx(ctx);
1565         case LTTNG_UST_CONTEXT_VPID:
1566                 return lttng_add_vpid_to_ctx(ctx);
1567         case LTTNG_UST_CONTEXT_PROCNAME:
1568                 return lttng_add_procname_to_ctx(ctx);
1569         case LTTNG_UST_CONTEXT_IP:
1570                 return lttng_add_ip_to_ctx(ctx);
1571         case LTTNG_UST_CONTEXT_CPU_ID:
1572                 return lttng_add_cpu_id_to_ctx(ctx);
1573         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1574                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1575                         ctx);
1576         case LTTNG_UST_CONTEXT_CGROUP_NS:
1577                 return lttng_add_cgroup_ns_to_ctx(ctx);
1578         case LTTNG_UST_CONTEXT_IPC_NS:
1579                 return lttng_add_ipc_ns_to_ctx(ctx);
1580         case LTTNG_UST_CONTEXT_MNT_NS:
1581                 return lttng_add_mnt_ns_to_ctx(ctx);
1582         case LTTNG_UST_CONTEXT_NET_NS:
1583                 return lttng_add_net_ns_to_ctx(ctx);
1584         case LTTNG_UST_CONTEXT_PID_NS:
1585                 return lttng_add_pid_ns_to_ctx(ctx);
1586         case LTTNG_UST_CONTEXT_TIME_NS:
1587                 return lttng_add_time_ns_to_ctx(ctx);
1588         case LTTNG_UST_CONTEXT_USER_NS:
1589                 return lttng_add_user_ns_to_ctx(ctx);
1590         case LTTNG_UST_CONTEXT_UTS_NS:
1591                 return lttng_add_uts_ns_to_ctx(ctx);
1592         case LTTNG_UST_CONTEXT_VUID:
1593                 return lttng_add_vuid_to_ctx(ctx);
1594         case LTTNG_UST_CONTEXT_VEUID:
1595                 return lttng_add_veuid_to_ctx(ctx);
1596         case LTTNG_UST_CONTEXT_VSUID:
1597                 return lttng_add_vsuid_to_ctx(ctx);
1598         case LTTNG_UST_CONTEXT_VGID:
1599                 return lttng_add_vgid_to_ctx(ctx);
1600         case LTTNG_UST_CONTEXT_VEGID:
1601                 return lttng_add_vegid_to_ctx(ctx);
1602         case LTTNG_UST_CONTEXT_VSGID:
1603                 return lttng_add_vsgid_to_ctx(ctx);
1604         default:
1605                 return -EINVAL;
1606         }
1607 }
1608
1609 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1610                 struct lttng_ust_context *context_param)
1611 {
1612         return -ENOSYS;
1613 }
1614
1615 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1616 {
1617         if (!event_enabler) {
1618                 return;
1619         }
1620         cds_list_del(&event_enabler->node);
1621
1622         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1623
1624         lttng_destroy_context(event_enabler->ctx);
1625         free(event_enabler);
1626 }
1627
1628 /*
1629  * lttng_session_sync_event_enablers should be called just before starting a
1630  * session.
1631  */
1632 static
1633 void lttng_session_sync_event_enablers(struct lttng_session *session)
1634 {
1635         struct lttng_event_enabler *event_enabler;
1636         struct lttng_event *event;
1637
1638         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1639                 lttng_event_enabler_ref_events(event_enabler);
1640         /*
1641          * For each event, if at least one of its enablers is enabled,
1642          * and its channel and session transient states are enabled, we
1643          * enable the event, else we disable it.
1644          */
1645         cds_list_for_each_entry(event, &session->events_head, node) {
1646                 struct lttng_enabler_ref *enabler_ref;
1647                 struct lttng_bytecode_runtime *runtime;
1648                 int enabled = 0, has_enablers_without_bytecode = 0;
1649
1650                 /* Enable events */
1651                 cds_list_for_each_entry(enabler_ref,
1652                                 &event->enablers_ref_head, node) {
1653                         if (enabler_ref->ref->enabled) {
1654                                 enabled = 1;
1655                                 break;
1656                         }
1657                 }
1658                 /*
1659                  * Enabled state is based on union of enablers, with
1660                  * intesection of session and channel transient enable
1661                  * states.
1662                  */
1663                 enabled = enabled && session->tstate && event->chan->tstate;
1664
1665                 CMM_STORE_SHARED(event->enabled, enabled);
1666                 /*
1667                  * Sync tracepoint registration with event enabled
1668                  * state.
1669                  */
1670                 if (enabled) {
1671                         if (!event->registered)
1672                                 register_event(event);
1673                 } else {
1674                         if (event->registered)
1675                                 unregister_event(event);
1676                 }
1677
1678                 /* Check if has enablers without bytecode enabled */
1679                 cds_list_for_each_entry(enabler_ref,
1680                                 &event->enablers_ref_head, node) {
1681                         if (enabler_ref->ref->enabled
1682                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1683                                 has_enablers_without_bytecode = 1;
1684                                 break;
1685                         }
1686                 }
1687                 event->has_enablers_without_bytecode =
1688                         has_enablers_without_bytecode;
1689
1690                 /* Enable filters */
1691                 cds_list_for_each_entry(runtime,
1692                                 &event->filter_bytecode_runtime_head, node) {
1693                         lttng_bytecode_filter_sync_state(runtime);
1694                 }
1695         }
1696         __tracepoint_probe_prune_release_queue();
1697 }
1698
1699 static
1700 void lttng_create_trigger_if_missing(struct lttng_trigger_enabler *trigger_enabler)
1701 {
1702         struct lttng_trigger_group *trigger_group = trigger_enabler->group;
1703         struct lttng_probe_desc *probe_desc;
1704         struct cds_list_head *probe_list;
1705         int i;
1706
1707         probe_list = lttng_get_probe_list_head();
1708
1709         cds_list_for_each_entry(probe_desc, probe_list, head) {
1710                 for (i = 0; i < probe_desc->nr_events; i++) {
1711                         int ret;
1712                         bool found = false;
1713                         const struct lttng_event_desc *desc;
1714                         struct lttng_trigger *trigger;
1715                         struct cds_hlist_head *head;
1716                         struct cds_hlist_node *node;
1717
1718                         desc = probe_desc->event_desc[i];
1719
1720                         if (!lttng_desc_match_enabler(desc,
1721                                         lttng_trigger_enabler_as_enabler(trigger_enabler)))
1722                                 continue;
1723
1724                         /*
1725                          * Given the current trigger group, get the bucket that
1726                          * the target trigger would be if it was already
1727                          * created.
1728                          */
1729                         head = borrow_hash_table_bucket(
1730                                 trigger_group->triggers_ht.table,
1731                                 LTTNG_UST_TRIGGER_HT_SIZE, desc);
1732
1733                         cds_hlist_for_each_entry(trigger, node, head, hlist) {
1734                                 /*
1735                                  * Check if trigger already exists by checking
1736                                  * if the trigger and enabler share the same
1737                                  * description and id.
1738                                  */
1739                                 if (trigger->desc == desc &&
1740                                                 trigger->id == trigger_enabler->id) {
1741                                         found = true;
1742                                         break;
1743                                 }
1744                         }
1745
1746                         if (found)
1747                                 continue;
1748
1749                         /*
1750                          * We need to create a trigger for this event probe.
1751                          */
1752                         ret = lttng_trigger_create(desc, trigger_enabler->id,
1753                                 trigger_enabler->error_counter_index,
1754                                 trigger_group);
1755                         if (ret) {
1756                                 DBG("Unable to create trigger %s, error %d\n",
1757                                         probe_desc->event_desc[i]->name, ret);
1758                         }
1759                 }
1760         }
1761 }
1762
1763 /*
1764  * Create triggers associated with a trigger enabler (if not already present).
1765  */
1766 static
1767 int lttng_trigger_enabler_ref_triggers(struct lttng_trigger_enabler *trigger_enabler)
1768 {
1769         struct lttng_trigger_group *trigger_group = trigger_enabler->group;
1770         struct lttng_trigger *trigger;
1771
1772          /*
1773           * Only try to create triggers for enablers that are enabled, the user
1774           * might still be attaching filter or exclusion to the
1775           * trigger_enabler.
1776           */
1777         if (!lttng_trigger_enabler_as_enabler(trigger_enabler)->enabled)
1778                 goto end;
1779
1780         /* First, ensure that probe triggers are created for this enabler. */
1781         lttng_create_trigger_if_missing(trigger_enabler);
1782
1783         /* Link the created trigger with its associated enabler. */
1784         cds_list_for_each_entry(trigger, &trigger_group->triggers_head, node) {
1785                 struct lttng_enabler_ref *enabler_ref;
1786
1787                 if (!lttng_trigger_enabler_match_trigger(trigger_enabler, trigger))
1788                         continue;
1789
1790                 enabler_ref = lttng_enabler_ref(&trigger->enablers_ref_head,
1791                         lttng_trigger_enabler_as_enabler(trigger_enabler));
1792                 if (!enabler_ref) {
1793                         /*
1794                          * If no backward ref, create it.
1795                          * Add backward ref from trigger to enabler.
1796                          */
1797                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1798                         if (!enabler_ref)
1799                                 return -ENOMEM;
1800
1801                         enabler_ref->ref = lttng_trigger_enabler_as_enabler(
1802                                 trigger_enabler);
1803                         cds_list_add(&enabler_ref->node,
1804                                 &trigger->enablers_ref_head);
1805                 }
1806
1807                 /*
1808                  * Link filter bytecodes if not linked yet.
1809                  */
1810                 lttng_enabler_link_bytecode(trigger->desc,
1811                         &trigger_group->ctx, &trigger->filter_bytecode_runtime_head,
1812                         &lttng_trigger_enabler_as_enabler(trigger_enabler)->filter_bytecode_head);
1813
1814                 /*
1815                  * Link capture bytecodes if not linked yet.
1816                  */
1817                 lttng_enabler_link_bytecode(trigger->desc,
1818                         &trigger_group->ctx, &trigger->capture_bytecode_runtime_head,
1819                         &trigger_enabler->capture_bytecode_head);
1820                 trigger->num_captures = trigger_enabler->num_captures;
1821         }
1822 end:
1823         return 0;
1824 }
1825
1826 static
1827 void lttng_trigger_group_sync_enablers(struct lttng_trigger_group *trigger_group)
1828 {
1829         struct lttng_trigger_enabler *trigger_enabler;
1830         struct lttng_trigger *trigger;
1831
1832         cds_list_for_each_entry(trigger_enabler, &trigger_group->enablers_head, node)
1833                 lttng_trigger_enabler_ref_triggers(trigger_enabler);
1834
1835         /*
1836          * For each trigger, if at least one of its enablers is enabled,
1837          * we enable the trigger, else we disable it.
1838          */
1839         cds_list_for_each_entry(trigger, &trigger_group->triggers_head, node) {
1840                 struct lttng_enabler_ref *enabler_ref;
1841                 struct lttng_bytecode_runtime *runtime;
1842                 int enabled = 0, has_enablers_without_bytecode = 0;
1843
1844                 /* Enable triggers */
1845                 cds_list_for_each_entry(enabler_ref,
1846                                 &trigger->enablers_ref_head, node) {
1847                         if (enabler_ref->ref->enabled) {
1848                                 enabled = 1;
1849                                 break;
1850                         }
1851                 }
1852
1853                 CMM_STORE_SHARED(trigger->enabled, enabled);
1854                 /*
1855                  * Sync tracepoint registration with trigger enabled
1856                  * state.
1857                  */
1858                 if (enabled) {
1859                         if (!trigger->registered)
1860                                 register_trigger(trigger);
1861                 } else {
1862                         if (trigger->registered)
1863                                 unregister_trigger(trigger);
1864                 }
1865
1866                 /* Check if has enablers without bytecode enabled */
1867                 cds_list_for_each_entry(enabler_ref,
1868                                 &trigger->enablers_ref_head, node) {
1869                         if (enabler_ref->ref->enabled
1870                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1871                                 has_enablers_without_bytecode = 1;
1872                                 break;
1873                         }
1874                 }
1875                 trigger->has_enablers_without_bytecode =
1876                         has_enablers_without_bytecode;
1877
1878                 /* Enable filters */
1879                 cds_list_for_each_entry(runtime,
1880                                 &trigger->filter_bytecode_runtime_head, node) {
1881                         lttng_bytecode_filter_sync_state(runtime);
1882                 }
1883
1884                 /* Enable captures. */
1885                 cds_list_for_each_entry(runtime,
1886                                 &trigger->capture_bytecode_runtime_head, node) {
1887                         lttng_bytecode_capture_sync_state(runtime);
1888                 }
1889         }
1890         __tracepoint_probe_prune_release_queue();
1891 }
1892
1893 /*
1894  * Apply enablers to session events, adding events to session if need
1895  * be. It is required after each modification applied to an active
1896  * session, and right before session "start".
1897  * "lazy" sync means we only sync if required.
1898  */
1899 static
1900 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1901 {
1902         /* We can skip if session is not active */
1903         if (!session->active)
1904                 return;
1905         lttng_session_sync_event_enablers(session);
1906 }
1907
1908 /*
1909  * Update all sessions with the given app context.
1910  * Called with ust lock held.
1911  * This is invoked when an application context gets loaded/unloaded. It
1912  * ensures the context callbacks are in sync with the application
1913  * context (either app context callbacks, or dummy callbacks).
1914  */
1915 void lttng_ust_context_set_session_provider(const char *name,
1916                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1917                 void (*record)(struct lttng_ctx_field *field,
1918                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1919                         struct lttng_channel *chan),
1920                 void (*get_value)(struct lttng_ctx_field *field,
1921                         struct lttng_ctx_value *value))
1922 {
1923         struct lttng_session *session;
1924
1925         cds_list_for_each_entry(session, &sessions, node) {
1926                 struct lttng_channel *chan;
1927                 struct lttng_event *event;
1928                 int ret;
1929
1930                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1931                                 name, get_size, record, get_value);
1932                 if (ret)
1933                         abort();
1934                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1935                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1936                                         name, get_size, record, get_value);
1937                         if (ret)
1938                                 abort();
1939                 }
1940                 cds_list_for_each_entry(event, &session->events_head, node) {
1941                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1942                                         name, get_size, record, get_value);
1943                         if (ret)
1944                                 abort();
1945                 }
1946         }
1947 }
1948
1949 /*
1950  * Update all trigger groups with the given app context.
1951  * Called with ust lock held.
1952  * This is invoked when an application context gets loaded/unloaded. It
1953  * ensures the context callbacks are in sync with the application
1954  * context (either app context callbacks, or dummy callbacks).
1955  */
1956 void lttng_ust_context_set_trigger_group_provider(const char *name,
1957                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1958                 void (*record)(struct lttng_ctx_field *field,
1959                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1960                         struct lttng_channel *chan),
1961                 void (*get_value)(struct lttng_ctx_field *field,
1962                         struct lttng_ctx_value *value))
1963 {
1964         struct lttng_trigger_group *trigger_group;
1965
1966         cds_list_for_each_entry(trigger_group, &trigger_groups, node) {
1967                 int ret;
1968
1969                 ret = lttng_ust_context_set_provider_rcu(&trigger_group->ctx,
1970                                 name, get_size, record, get_value);
1971                 if (ret)
1972                         abort();
1973         }
1974 }