liblttng-ust/lttng-events.c

   1 /*
   2  * lttng-events.c
   3  *
   4  * Holds LTTng per-session event registry.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _LGPL_SOURCE
  24 #include <stdio.h>
  25 #include <assert.h>
  26 #include <errno.h>
  27 #include <limits.h>
  28 #include <pthread.h>
  29 #include <sys/shm.h>
  30 #include <sys/ipc.h>
  31 #include <stdint.h>
  32 #include <stddef.h>
  33 #include <inttypes.h>
  34 #include <time.h>
  35 #include <stdbool.h>
  36 #include <unistd.h>
  37 #include <lttng/ust-endian.h>
  38
  39 #include <urcu-bp.h>
  40 #include <urcu/arch.h>
  41 #include <urcu/compiler.h>
  42 #include <urcu/hlist.h>
  43 #include <urcu/list.h>
  44 #include <urcu/uatomic.h>
  45
  46 #include <lttng/tracepoint.h>
  47 #include <lttng/ust-events.h>
  48
  49 #include <usterr-signal-safe.h>
  50 #include <helper.h>
  51 #include <lttng/ust-ctl.h>
  52 #include <ust-comm.h>
  53 #include <ust-fd.h>
  54 #include <lttng/ust-dynamic-type.h>
  55 #include <lttng/ust-context-provider.h>
  56 #include "error.h"
  57 #include "compat.h"
  58 #include "lttng-ust-uuid.h"
  59
  60 #include "tracepoint-internal.h"
  61 #include "string-utils.h"
  62 #include "lttng-bytecode.h"
  63 #include "lttng-tracer.h"
  64 #include "lttng-tracer-core.h"
  65 #include "lttng-ust-statedump.h"
  66 #include "context-internal.h"
  67 #include "ust-events-internal.h"
  68 #include "wait.h"
  69 #include "../libringbuffer/shm.h"
  70 #include "../libcounter/counter.h"
  71 #include "jhash.h"
  72 #include <lttng/ust-abi.h>
  73
  74 /*
  75  * All operations within this file are called by the communication
  76  * thread, under ust_lock protection.
  77  */
  78
  79 static CDS_LIST_HEAD(sessions);
  80 static CDS_LIST_HEAD(event_notifier_groups);
  81
  82 struct cds_list_head *_lttng_get_sessions(void)
  83 {
  84         return &sessions;
  85 }
  86
  87 static void _lttng_event_destroy(struct lttng_event *event);
  88 static void _lttng_event_notifier_destroy(
  89                 struct lttng_event_notifier *event_notifier);
  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_event_notifier_group_sync_enablers(
  98                 struct lttng_event_notifier_group *event_notifier_group);
  99 static
 100 void lttng_enabler_destroy(struct lttng_enabler *enabler);
 101
 102 /*
 103  * Called with ust lock held.
 104  */
 105 int lttng_session_active(void)
 106 {
 107         struct lttng_session *iter;
 108
 109         cds_list_for_each_entry(iter, &sessions, node) {
 110                 if (iter->active)
 111                         return 1;
 112         }
 113         return 0;
 114 }
 115
 116 static
 117 int lttng_loglevel_match(int loglevel,
 118                 unsigned int has_loglevel,
 119                 enum lttng_ust_loglevel_type req_type,
 120                 int req_loglevel)
 121 {
 122         if (!has_loglevel)
 123                 loglevel = TRACE_DEFAULT;
 124         switch (req_type) {
 125         case LTTNG_UST_LOGLEVEL_RANGE:
 126                 if (loglevel <= req_loglevel
 127                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 128                         return 1;
 129                 else
 130                         return 0;
 131         case LTTNG_UST_LOGLEVEL_SINGLE:
 132                 if (loglevel == req_loglevel
 133                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 134                         return 1;
 135                 else
 136                         return 0;
 137         case LTTNG_UST_LOGLEVEL_ALL:
 138         default:
 139                 if (loglevel <= TRACE_DEBUG)
 140                         return 1;
 141                 else
 142                         return 0;
 143         }
 144 }
 145
 146 void synchronize_trace(void)
 147 {
 148         synchronize_rcu();
 149 }
 150
 151 struct lttng_session *lttng_session_create(void)
 152 {
 153         struct lttng_session *session;
 154         int i;
 155
 156         session = zmalloc(sizeof(struct lttng_session));
 157         if (!session)
 158                 return NULL;
 159         if (lttng_context_init_all(&session->ctx)) {
 160                 free(session);
 161                 return NULL;
 162         }
 163         CDS_INIT_LIST_HEAD(&session->chan_head);
 164         CDS_INIT_LIST_HEAD(&session->events_head);
 165         CDS_INIT_LIST_HEAD(&session->enums_head);
 166         CDS_INIT_LIST_HEAD(&session->enablers_head);
 167         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 168                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 169         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 170                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 171         cds_list_add(&session->node, &sessions);
 172         return session;
 173 }
 174
 175 struct lttng_counter *lttng_ust_counter_create(
 176                 const char *counter_transport_name,
 177                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 178 {
 179         struct lttng_counter_transport *counter_transport = NULL;
 180         struct lttng_counter *counter = NULL;
 181
 182         counter_transport = lttng_counter_transport_find(counter_transport_name);
 183         if (!counter_transport)
 184                 goto notransport;
 185         counter = zmalloc(sizeof(struct lttng_counter));
 186         if (!counter)
 187                 goto nomem;
 188
 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_event_notifier_group *lttng_event_notifier_group_create(void)
 216 {
 217         struct lttng_event_notifier_group *event_notifier_group;
 218         int i;
 219
 220         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 221         if (!event_notifier_group)
 222                 return NULL;
 223
 224         /* Add all contexts. */
 225         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 226                 free(event_notifier_group);
 227                 return NULL;
 228         }
 229
 230         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 231         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 232         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 233                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 234
 235         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 236
 237         return event_notifier_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_event_notifier(struct lttng_event_notifier *event_notifier)
 278 {
 279         int ret;
 280         const struct lttng_event_desc *desc;
 281
 282         assert(event_notifier->registered == 0);
 283         desc = event_notifier->desc;
 284         ret = __tracepoint_probe_register_queue_release(desc->name,
 285                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 286         WARN_ON_ONCE(ret);
 287         if (!ret)
 288                 event_notifier->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_event_notifier(struct lttng_event_notifier *event_notifier)
 309 {
 310         int ret;
 311         const struct lttng_event_desc *desc;
 312
 313         assert(event_notifier->registered == 1);
 314         desc = event_notifier->desc;
 315         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 316                 desc->u.ext.event_notifier_callback, event_notifier);
 317         WARN_ON_ONCE(ret);
 318         if (!ret)
 319                 event_notifier->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_event_notifier_unregister(struct lttng_event_notifier *event_notifier)
 337 {
 338         if (event_notifier->registered)
 339                 unregister_event_notifier(event_notifier);
 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_event_notifier_group_destroy(
 372                 struct lttng_event_notifier_group *event_notifier_group)
 373 {
 374         int close_ret;
 375         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 376         struct lttng_event_notifier *notifier, *tmpnotifier;
 377
 378         if (!event_notifier_group) {
 379                 return;
 380         }
 381
 382         cds_list_for_each_entry(notifier,
 383                         &event_notifier_group->event_notifiers_head, node)
 384                 _lttng_event_notifier_unregister(notifier);
 385
 386         synchronize_trace();
 387
 388         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 389                         &event_notifier_group->enablers_head, node)
 390                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 391
 392         cds_list_for_each_entry_safe(notifier, tmpnotifier,
 393                         &event_notifier_group->event_notifiers_head, node)
 394                 _lttng_event_notifier_destroy(notifier);
 395
 396         if (event_notifier_group->error_counter)
 397                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 398
 399         /* Close the notification fd to the listener of event_notifiers. */
 400
 401         lttng_ust_lock_fd_tracker();
 402         close_ret = close(event_notifier_group->notification_fd);
 403         if (!close_ret) {
 404                 lttng_ust_delete_fd_from_tracker(
 405                                 event_notifier_group->notification_fd);
 406         } else {
 407                 PERROR("close");
 408                 abort();
 409         }
 410         lttng_ust_unlock_fd_tracker();
 411
 412         cds_list_del(&event_notifier_group->node);
 413
 414         free(event_notifier_group);
 415 }
 416
 417 static
 418 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 419 {
 420         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 421         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 422
 423         if (!enabler) {
 424                 return;
 425         }
 426
 427         /* Destroy filter bytecode */
 428         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 429                         &enabler->filter_bytecode_head, node) {
 430                 free(filter_node);
 431         }
 432
 433         /* Destroy excluders */
 434         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 435                         &enabler->excluder_head, node) {
 436                 free(excluder_node);
 437         }
 438 }
 439
 440  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 441 {
 442         if (!event_notifier_enabler) {
 443                 return;
 444         }
 445
 446         cds_list_del(&event_notifier_enabler->node);
 447
 448         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 449
 450         free(event_notifier_enabler);
 451 }
 452
 453 static
 454 int lttng_enum_create(const struct lttng_enum_desc *desc,
 455                 struct lttng_session *session)
 456 {
 457         const char *enum_name = desc->name;
 458         struct lttng_enum *_enum;
 459         struct cds_hlist_head *head;
 460         int ret = 0;
 461         size_t name_len = strlen(enum_name);
 462         uint32_t hash;
 463         int notify_socket;
 464
 465         /* Check if this enum is already registered for this session. */
 466         hash = jhash(enum_name, name_len, 0);
 467         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 468
 469         _enum = lttng_ust_enum_get_from_desc(session, desc);
 470         if (_enum) {
 471                 ret = -EEXIST;
 472                 goto exist;
 473         }
 474
 475         notify_socket = lttng_get_notify_socket(session->owner);
 476         if (notify_socket < 0) {
 477                 ret = notify_socket;
 478                 goto socket_error;
 479         }
 480
 481         _enum = zmalloc(sizeof(*_enum));
 482         if (!_enum) {
 483                 ret = -ENOMEM;
 484                 goto cache_error;
 485         }
 486         _enum->session = session;
 487         _enum->desc = desc;
 488
 489         ret = ustcomm_register_enum(notify_socket,
 490                 session->objd,
 491                 enum_name,
 492                 desc->nr_entries,
 493                 desc->entries,
 494                 &_enum->id);
 495         if (ret < 0) {
 496                 DBG("Error (%d) registering enumeration to sessiond", ret);
 497                 goto sessiond_register_error;
 498         }
 499         cds_list_add(&_enum->node, &session->enums_head);
 500         cds_hlist_add_head(&_enum->hlist, head);
 501         return 0;
 502
 503 sessiond_register_error:
 504         free(_enum);
 505 cache_error:
 506 socket_error:
 507 exist:
 508         return ret;
 509 }
 510
 511 static
 512 int lttng_create_enum_check(const struct lttng_type *type,
 513                 struct lttng_session *session)
 514 {
 515         switch (type->atype) {
 516         case atype_enum:
 517         {
 518                 const struct lttng_enum_desc *enum_desc;
 519                 int ret;
 520
 521                 enum_desc = type->u.legacy.basic.enumeration.desc;
 522                 ret = lttng_enum_create(enum_desc, session);
 523                 if (ret && ret != -EEXIST) {
 524                         DBG("Unable to create enum error: (%d)", ret);
 525                         return ret;
 526                 }
 527                 break;
 528         }
 529         case atype_enum_nestable:
 530         {
 531                 const struct lttng_enum_desc *enum_desc;
 532                 int ret;
 533
 534                 enum_desc = type->u.enum_nestable.desc;
 535                 ret = lttng_enum_create(enum_desc, session);
 536                 if (ret && ret != -EEXIST) {
 537                         DBG("Unable to create enum error: (%d)", ret);
 538                         return ret;
 539                 }
 540                 break;
 541         }
 542         case atype_dynamic:
 543         {
 544                 const struct lttng_event_field *tag_field_generic;
 545                 const struct lttng_enum_desc *enum_desc;
 546                 int ret;
 547
 548                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 549                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 550                 ret = lttng_enum_create(enum_desc, session);
 551                 if (ret && ret != -EEXIST) {
 552                         DBG("Unable to create enum error: (%d)", ret);
 553                         return ret;
 554                 }
 555                 break;
 556         }
 557         default:
 558                 /* TODO: nested types when they become supported. */
 559                 break;
 560         }
 561         return 0;
 562 }
 563
 564 static
 565 int lttng_create_all_event_enums(size_t nr_fields,
 566                 const struct lttng_event_field *event_fields,
 567                 struct lttng_session *session)
 568 {
 569         size_t i;
 570         int ret;
 571
 572         /* For each field, ensure enum is part of the session. */
 573         for (i = 0; i < nr_fields; i++) {
 574                 const struct lttng_type *type = &event_fields[i].type;
 575
 576                 ret = lttng_create_enum_check(type, session);
 577                 if (ret)
 578                         return ret;
 579         }
 580         return 0;
 581 }
 582
 583 static
 584 int lttng_create_all_ctx_enums(size_t nr_fields,
 585                 const struct lttng_ctx_field *ctx_fields,
 586                 struct lttng_session *session)
 587 {
 588         size_t i;
 589         int ret;
 590
 591         /* For each field, ensure enum is part of the session. */
 592         for (i = 0; i < nr_fields; i++) {
 593                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 594
 595                 ret = lttng_create_enum_check(type, session);
 596                 if (ret)
 597                         return ret;
 598         }
 599         return 0;
 600 }
 601
 602 /*
 603  * Ensure that a state-dump will be performed for this session at the end
 604  * of the current handle_message().
 605  */
 606 int lttng_session_statedump(struct lttng_session *session)
 607 {
 608         session->statedump_pending = 1;
 609         lttng_ust_sockinfo_session_enabled(session->owner);
 610         return 0;
 611 }
 612
 613 int lttng_session_enable(struct lttng_session *session)
 614 {
 615         int ret = 0;
 616         struct lttng_channel *chan;
 617         int notify_socket;
 618
 619         if (session->active) {
 620                 ret = -EBUSY;
 621                 goto end;
 622         }
 623
 624         notify_socket = lttng_get_notify_socket(session->owner);
 625         if (notify_socket < 0)
 626                 return notify_socket;
 627
 628         /* Set transient enabler state to "enabled" */
 629         session->tstate = 1;
 630
 631         /* We need to sync enablers with session before activation. */
 632         lttng_session_sync_event_enablers(session);
 633
 634         /*
 635          * Snapshot the number of events per channel to know the type of header
 636          * we need to use.
 637          */
 638         cds_list_for_each_entry(chan, &session->chan_head, node) {
 639                 const struct lttng_ctx *ctx;
 640                 const struct lttng_ctx_field *fields = NULL;
 641                 size_t nr_fields = 0;
 642                 uint32_t chan_id;
 643
 644                 /* don't change it if session stop/restart */
 645                 if (chan->header_type)
 646                         continue;
 647                 ctx = chan->ctx;
 648                 if (ctx) {
 649                         nr_fields = ctx->nr_fields;
 650                         fields = ctx->fields;
 651                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 652                                 session);
 653                         if (ret < 0) {
 654                                 DBG("Error (%d) adding enum to session", ret);
 655                                 return ret;
 656                         }
 657                 }
 658                 ret = ustcomm_register_channel(notify_socket,
 659                         session,
 660                         session->objd,
 661                         chan->objd,
 662                         nr_fields,
 663                         fields,
 664                         &chan_id,
 665                         &chan->header_type);
 666                 if (ret) {
 667                         DBG("Error (%d) registering channel to sessiond", ret);
 668                         return ret;
 669                 }
 670                 if (chan_id != chan->id) {
 671                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 672                                 chan_id, chan->id);
 673                         return -EINVAL;
 674                 }
 675         }
 676
 677         /* Set atomically the state to "active" */
 678         CMM_ACCESS_ONCE(session->active) = 1;
 679         CMM_ACCESS_ONCE(session->been_active) = 1;
 680
 681         ret = lttng_session_statedump(session);
 682         if (ret)
 683                 return ret;
 684 end:
 685         return ret;
 686 }
 687
 688 int lttng_session_disable(struct lttng_session *session)
 689 {
 690         int ret = 0;
 691
 692         if (!session->active) {
 693                 ret = -EBUSY;
 694                 goto end;
 695         }
 696         /* Set atomically the state to "inactive" */
 697         CMM_ACCESS_ONCE(session->active) = 0;
 698
 699         /* Set transient enabler state to "disabled" */
 700         session->tstate = 0;
 701         lttng_session_sync_event_enablers(session);
 702 end:
 703         return ret;
 704 }
 705
 706 int lttng_channel_enable(struct lttng_channel *channel)
 707 {
 708         int ret = 0;
 709
 710         if (channel->enabled) {
 711                 ret = -EBUSY;
 712                 goto end;
 713         }
 714         /* Set transient enabler state to "enabled" */
 715         channel->tstate = 1;
 716         lttng_session_sync_event_enablers(channel->session);
 717         /* Set atomically the state to "enabled" */
 718         CMM_ACCESS_ONCE(channel->enabled) = 1;
 719 end:
 720         return ret;
 721 }
 722
 723 int lttng_channel_disable(struct lttng_channel *channel)
 724 {
 725         int ret = 0;
 726
 727         if (!channel->enabled) {
 728                 ret = -EBUSY;
 729                 goto end;
 730         }
 731         /* Set atomically the state to "disabled" */
 732         CMM_ACCESS_ONCE(channel->enabled) = 0;
 733         /* Set transient enabler state to "enabled" */
 734         channel->tstate = 0;
 735         lttng_session_sync_event_enablers(channel->session);
 736 end:
 737         return ret;
 738 }
 739
 740 static inline
 741 struct cds_hlist_head *borrow_hash_table_bucket(
 742                 struct cds_hlist_head *hash_table,
 743                 unsigned int hash_table_size,
 744                 const struct lttng_event_desc *desc)
 745 {
 746         const char *event_name;
 747         size_t name_len;
 748         uint32_t hash;
 749
 750         event_name = desc->name;
 751         name_len = strlen(event_name);
 752
 753         hash = jhash(event_name, name_len, 0);
 754         return &hash_table[hash & (hash_table_size - 1)];
 755 }
 756
 757 /*
 758  * Supports event creation while tracing session is active.
 759  */
 760 static
 761 int lttng_event_create(const struct lttng_event_desc *desc,
 762                 struct lttng_channel *chan)
 763 {
 764         struct lttng_event *event;
 765         struct lttng_session *session = chan->session;
 766         struct cds_hlist_head *head;
 767         int ret = 0;
 768         int notify_socket, loglevel;
 769         const char *uri;
 770
 771         head = borrow_hash_table_bucket(chan->session->events_ht.table,
 772                 LTTNG_UST_EVENT_HT_SIZE, desc);
 773
 774         notify_socket = lttng_get_notify_socket(session->owner);
 775         if (notify_socket < 0) {
 776                 ret = notify_socket;
 777                 goto socket_error;
 778         }
 779
 780         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 781                         session);
 782         if (ret < 0) {
 783                 DBG("Error (%d) adding enum to session", ret);
 784                 goto create_enum_error;
 785         }
 786
 787         /*
 788          * Check if loglevel match. Refuse to connect event if not.
 789          */
 790         event = zmalloc(sizeof(struct lttng_event));
 791         if (!event) {
 792                 ret = -ENOMEM;
 793                 goto cache_error;
 794         }
 795         event->chan = chan;
 796
 797         /* Event will be enabled by enabler sync. */
 798         event->enabled = 0;
 799         event->registered = 0;
 800         CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
 801         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 802         event->desc = desc;
 803
 804         if (desc->loglevel)
 805                 loglevel = *(*event->desc->loglevel);
 806         else
 807                 loglevel = TRACE_DEFAULT;
 808         if (desc->u.ext.model_emf_uri)
 809                 uri = *(desc->u.ext.model_emf_uri);
 810         else
 811                 uri = NULL;
 812
 813         /* Fetch event ID from sessiond */
 814         ret = ustcomm_register_event(notify_socket,
 815                 session,
 816                 session->objd,
 817                 chan->objd,
 818                 desc->name,
 819                 loglevel,
 820                 desc->signature,
 821                 desc->nr_fields,
 822                 desc->fields,
 823                 uri,
 824                 &event->id);
 825         if (ret < 0) {
 826                 DBG("Error (%d) registering event to sessiond", ret);
 827                 goto sessiond_register_error;
 828         }
 829
 830         cds_list_add(&event->node, &chan->session->events_head);
 831         cds_hlist_add_head(&event->hlist, head);
 832         return 0;
 833
 834 sessiond_register_error:
 835         free(event);
 836 cache_error:
 837 create_enum_error:
 838 socket_error:
 839         return ret;
 840 }
 841
 842 static
 843 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 844                 uint64_t token,
 845                 struct lttng_event_notifier_group *event_notifier_group)
 846 {
 847         struct lttng_event_notifier *event_notifier;
 848         struct cds_hlist_head *head;
 849         int ret = 0;
 850
 851         /*
 852          * Get the hashtable bucket the created lttng_event_notifier object
 853          * should be inserted.
 854          */
 855         head = borrow_hash_table_bucket(
 856                 event_notifier_group->event_notifiers_ht.table,
 857                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 858
 859         event_notifier = zmalloc(sizeof(struct lttng_event_notifier));
 860         if (!event_notifier) {
 861                 ret = -ENOMEM;
 862                 goto error;
 863         }
 864
 865         event_notifier->group = event_notifier_group;
 866         event_notifier->user_token = token;
 867
 868         /* Event notifier will be enabled by enabler sync. */
 869         event_notifier->enabled = 0;
 870         event_notifier->registered = 0;
 871
 872         CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
 873         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 874         CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
 875         event_notifier->desc = desc;
 876
 877         cds_list_add(&event_notifier->node,
 878                         &event_notifier_group->event_notifiers_head);
 879         cds_hlist_add_head(&event_notifier->hlist, head);
 880
 881         return 0;
 882
 883 error:
 884         return ret;
 885 }
 886
 887 static
 888 void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
 889 {
 890         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 891
 892         /* Remove from event_notifier list. */
 893         cds_list_del(&event_notifier->node);
 894         /* Remove from event_notifier hash table. */
 895         cds_hlist_del(&event_notifier->hlist);
 896
 897         lttng_free_event_notifier_filter_runtime(event_notifier);
 898
 899         /* Free event_notifier enabler refs */
 900         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 901                         &event_notifier->enablers_ref_head, node)
 902                 free(enabler_ref);
 903         free(event_notifier);
 904 }
 905
 906 static
 907 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 908                 struct lttng_enabler *enabler)
 909 {
 910         int loglevel = 0;
 911         unsigned int has_loglevel = 0;
 912
 913         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 914         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 915                         desc->name, SIZE_MAX))
 916                 return 0;
 917         if (desc->loglevel) {
 918                 loglevel = *(*desc->loglevel);
 919                 has_loglevel = 1;
 920         }
 921         if (!lttng_loglevel_match(loglevel,
 922                         has_loglevel,
 923                         enabler->event_param.loglevel_type,
 924                         enabler->event_param.loglevel))
 925                 return 0;
 926         return 1;
 927 }
 928
 929 static
 930 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 931                 struct lttng_enabler *enabler)
 932 {
 933         int loglevel = 0;
 934         unsigned int has_loglevel = 0;
 935
 936         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 937         if (strcmp(desc->name, enabler->event_param.name))
 938                 return 0;
 939         if (desc->loglevel) {
 940                 loglevel = *(*desc->loglevel);
 941                 has_loglevel = 1;
 942         }
 943         if (!lttng_loglevel_match(loglevel,
 944                         has_loglevel,
 945                         enabler->event_param.loglevel_type,
 946                         enabler->event_param.loglevel))
 947                 return 0;
 948         return 1;
 949 }
 950
 951 static
 952 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 953                 struct lttng_enabler *enabler)
 954 {
 955         switch (enabler->format_type) {
 956         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 957         {
 958                 struct lttng_ust_excluder_node *excluder;
 959
 960                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 961                         return 0;
 962                 }
 963
 964                 /*
 965                  * If the matching event matches with an excluder,
 966                  * return 'does not match'
 967                  */
 968                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 969                         int count;
 970
 971                         for (count = 0; count < excluder->excluder.count; count++) {
 972                                 int len;
 973                                 char *excluder_name;
 974
 975                                 excluder_name = (char *) (excluder->excluder.names)
 976                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 977                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 978                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 979                                         return 0;
 980                         }
 981                 }
 982                 return 1;
 983         }
 984         case LTTNG_ENABLER_FORMAT_EVENT:
 985                 return lttng_desc_match_event_enabler(desc, enabler);
 986         default:
 987                 return -EINVAL;
 988         }
 989 }
 990
 991 static
 992 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 993                 struct lttng_event *event)
 994 {
 995         if (lttng_desc_match_enabler(event->desc,
 996                         lttng_event_enabler_as_enabler(event_enabler))
 997                         && event->chan == event_enabler->chan)
 998                 return 1;
 999         else
1000                 return 0;
1001 }
1002
1003 static
1004 int lttng_event_notifier_enabler_match_event_notifier(
1005                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1006                 struct lttng_event_notifier *event_notifier)
1007 {
1008         int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
1009                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1010
1011         if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
1012                         event_notifier->user_token == event_notifier_enabler->user_token)
1013                 return 1;
1014         else
1015                 return 0;
1016 }
1017
1018 static
1019 struct lttng_enabler_ref *lttng_enabler_ref(
1020                 struct cds_list_head *enabler_ref_list,
1021                 struct lttng_enabler *enabler)
1022 {
1023         struct lttng_enabler_ref *enabler_ref;
1024
1025         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1026                 if (enabler_ref->ref == enabler)
1027                         return enabler_ref;
1028         }
1029         return NULL;
1030 }
1031
1032 /*
1033  * Create struct lttng_event if it is missing and present in the list of
1034  * tracepoint probes.
1035  */
1036 static
1037 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1038 {
1039         struct lttng_session *session = event_enabler->chan->session;
1040         struct lttng_probe_desc *probe_desc;
1041         const struct lttng_event_desc *desc;
1042         struct lttng_event *event;
1043         int i;
1044         struct cds_list_head *probe_list;
1045
1046         probe_list = lttng_get_probe_list_head();
1047         /*
1048          * For each probe event, if we find that a probe event matches
1049          * our enabler, create an associated lttng_event if not
1050          * already present.
1051          */
1052         cds_list_for_each_entry(probe_desc, probe_list, head) {
1053                 for (i = 0; i < probe_desc->nr_events; i++) {
1054                         int ret;
1055                         bool found = false;
1056                         struct cds_hlist_head *head;
1057                         struct cds_hlist_node *node;
1058
1059                         desc = probe_desc->event_desc[i];
1060                         if (!lttng_desc_match_enabler(desc,
1061                                         lttng_event_enabler_as_enabler(event_enabler)))
1062                                 continue;
1063
1064                         head = borrow_hash_table_bucket(
1065                                 session->events_ht.table,
1066                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1067
1068                         cds_hlist_for_each_entry(event, node, head, hlist) {
1069                                 if (event->desc == desc
1070                                                 && event->chan == event_enabler->chan) {
1071                                         found = true;
1072                                         break;
1073                                 }
1074                         }
1075                         if (found)
1076                                 continue;
1077
1078                         /*
1079                          * We need to create an event for this
1080                          * event probe.
1081                          */
1082                         ret = lttng_event_create(probe_desc->event_desc[i],
1083                                         event_enabler->chan);
1084                         if (ret) {
1085                                 DBG("Unable to create event %s, error %d\n",
1086                                         probe_desc->event_desc[i]->name, ret);
1087                         }
1088                 }
1089         }
1090 }
1091
1092 static
1093 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1094                 void (*event_func)(struct lttng_session *session,
1095                         struct lttng_event *event),
1096                 void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
1097 {
1098         struct cds_hlist_node *node, *tmp_node;
1099         struct cds_list_head *sessionsp;
1100         unsigned int i;
1101
1102         /* Get handle on list of sessions. */
1103         sessionsp = _lttng_get_sessions();
1104
1105         /*
1106          * Iterate over all events in the probe provider descriptions and
1107          * sessions to queue the unregistration of the events.
1108          */
1109         for (i = 0; i < provider_desc->nr_events; i++) {
1110                 const struct lttng_event_desc *event_desc;
1111                 struct lttng_event_notifier_group *event_notifier_group;
1112                 struct lttng_event_notifier *event_notifier;
1113                 struct lttng_session *session;
1114                 struct cds_hlist_head *head;
1115                 struct lttng_event *event;
1116
1117                 event_desc = provider_desc->event_desc[i];
1118
1119                 /*
1120                  * Iterate over all session to find the current event
1121                  * description.
1122                  */
1123                 cds_list_for_each_entry(session, sessionsp, node) {
1124                         /*
1125                          * Get the list of events in the hashtable bucket and
1126                          * iterate to find the event matching this descriptor.
1127                          */
1128                         head = borrow_hash_table_bucket(
1129                                 session->events_ht.table,
1130                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1131
1132                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1133                                 if (event_desc == event->desc) {
1134                                         event_func(session, event);
1135                                         break;
1136                                 }
1137                         }
1138                 }
1139
1140                 /*
1141                  * Iterate over all event_notifier groups to find the current event
1142                  * description.
1143                  */
1144                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1145                         /*
1146                          * Get the list of event_notifiers in the hashtable bucket and
1147                          * iterate to find the event_notifier matching this
1148                          * descriptor.
1149                          */
1150                         head = borrow_hash_table_bucket(
1151                                 event_notifier_group->event_notifiers_ht.table,
1152                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1153
1154                         cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
1155                                 if (event_desc == event_notifier->desc) {
1156                                         event_notifier_func(event_notifier);
1157                                         break;
1158                                 }
1159                         }
1160                 }
1161         }
1162 }
1163
1164 static
1165 void _unregister_event(struct lttng_session *session,
1166                 struct lttng_event *event)
1167 {
1168         _lttng_event_unregister(event);
1169 }
1170
1171 static
1172 void _event_enum_destroy(struct lttng_session *session,
1173                 struct lttng_event *event)
1174 {
1175         unsigned int i;
1176
1177         /* Destroy enums of the current event. */
1178         for (i = 0; i < event->desc->nr_fields; i++) {
1179                 const struct lttng_enum_desc *enum_desc;
1180                 const struct lttng_event_field *field;
1181                 struct lttng_enum *curr_enum;
1182
1183                 field = &(event->desc->fields[i]);
1184                 switch (field->type.atype) {
1185                 case atype_enum:
1186                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1187                         break;
1188                 case atype_enum_nestable:
1189                         enum_desc = field->type.u.enum_nestable.desc;
1190                         break;
1191                 default:
1192                         continue;
1193                 }
1194
1195                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1196                 if (curr_enum) {
1197                         _lttng_enum_destroy(curr_enum);
1198                 }
1199         }
1200
1201         /* Destroy event. */
1202         _lttng_event_destroy(event);
1203 }
1204
1205 /*
1206  * Iterate over all the UST sessions to unregister and destroy all probes from
1207  * the probe provider descriptor received as argument. Must me called with the
1208  * ust_lock held.
1209  */
1210 void lttng_probe_provider_unregister_events(
1211                 struct lttng_probe_desc *provider_desc)
1212 {
1213         /*
1214          * Iterate over all events in the probe provider descriptions and sessions
1215          * to queue the unregistration of the events.
1216          */
1217         probe_provider_event_for_each(provider_desc, _unregister_event,
1218                 _lttng_event_notifier_unregister);
1219
1220         /* Wait for grace period. */
1221         synchronize_trace();
1222         /* Prune the unregistration queue. */
1223         __tracepoint_probe_prune_release_queue();
1224
1225         /*
1226          * It is now safe to destroy the events and remove them from the event list
1227          * and hashtables.
1228          */
1229         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1230                 _lttng_event_notifier_destroy);
1231 }
1232
1233 /*
1234  * Create events associated with an event enabler (if not already present),
1235  * and add backward reference from the event to the enabler.
1236  */
1237 static
1238 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1239 {
1240         struct lttng_session *session = event_enabler->chan->session;
1241         struct lttng_event *event;
1242
1243         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1244                 goto end;
1245
1246         /* First ensure that probe events are created for this enabler. */
1247         lttng_create_event_if_missing(event_enabler);
1248
1249         /* For each event matching enabler in session event list. */
1250         cds_list_for_each_entry(event, &session->events_head, node) {
1251                 struct lttng_enabler_ref *enabler_ref;
1252
1253                 if (!lttng_event_enabler_match_event(event_enabler, event))
1254                         continue;
1255
1256                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1257                         lttng_event_enabler_as_enabler(event_enabler));
1258                 if (!enabler_ref) {
1259                         /*
1260                          * If no backward ref, create it.
1261                          * Add backward ref from event to enabler.
1262                          */
1263                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1264                         if (!enabler_ref)
1265                                 return -ENOMEM;
1266                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1267                                 event_enabler);
1268                         cds_list_add(&enabler_ref->node,
1269                                 &event->enablers_ref_head);
1270                 }
1271
1272                 /*
1273                  * Link filter bytecodes if not linked yet.
1274                  */
1275                 lttng_enabler_link_bytecode(event->desc,
1276                         &session->ctx,
1277                         &event->filter_bytecode_runtime_head,
1278                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1279
1280                 /* TODO: merge event context. */
1281         }
1282 end:
1283         return 0;
1284 }
1285
1286 /*
1287  * Called at library load: connect the probe on all enablers matching
1288  * this event.
1289  * Called with session mutex held.
1290  */
1291 int lttng_fix_pending_events(void)
1292 {
1293         struct lttng_session *session;
1294
1295         cds_list_for_each_entry(session, &sessions, node) {
1296                 lttng_session_lazy_sync_event_enablers(session);
1297         }
1298         return 0;
1299 }
1300
1301 int lttng_fix_pending_event_notifiers(void)
1302 {
1303         struct lttng_event_notifier_group *event_notifier_group;
1304
1305         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1306                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1307         }
1308         return 0;
1309 }
1310
1311 /*
1312  * For each session of the owner thread, execute pending statedump.
1313  * Only dump state for the sessions owned by the caller thread, because
1314  * we don't keep ust_lock across the entire iteration.
1315  */
1316 void lttng_handle_pending_statedump(void *owner)
1317 {
1318         struct lttng_session *session;
1319
1320         /* Execute state dump */
1321         do_lttng_ust_statedump(owner);
1322
1323         /* Clear pending state dump */
1324         if (ust_lock()) {
1325                 goto end;
1326         }
1327         cds_list_for_each_entry(session, &sessions, node) {
1328                 if (session->owner != owner)
1329                         continue;
1330                 if (!session->statedump_pending)
1331                         continue;
1332                 session->statedump_pending = 0;
1333         }
1334 end:
1335         ust_unlock();
1336         return;
1337 }
1338
1339 /*
1340  * Only used internally at session destruction.
1341  */
1342 static
1343 void _lttng_event_destroy(struct lttng_event *event)
1344 {
1345         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1346
1347         /* Remove from event list. */
1348         cds_list_del(&event->node);
1349         /* Remove from event hash table. */
1350         cds_hlist_del(&event->hlist);
1351
1352         lttng_destroy_context(event->ctx);
1353         lttng_free_event_filter_runtime(event);
1354         /* Free event enabler refs */
1355         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1356                         &event->enablers_ref_head, node)
1357                 free(enabler_ref);
1358         free(event);
1359 }
1360
1361 static
1362 void _lttng_enum_destroy(struct lttng_enum *_enum)
1363 {
1364         cds_list_del(&_enum->node);
1365         cds_hlist_del(&_enum->hlist);
1366         free(_enum);
1367 }
1368
1369 void lttng_ust_events_exit(void)
1370 {
1371         struct lttng_session *session, *tmpsession;
1372
1373         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1374                 lttng_session_destroy(session);
1375 }
1376
1377 /*
1378  * Enabler management.
1379  */
1380 struct lttng_event_enabler *lttng_event_enabler_create(
1381                 enum lttng_enabler_format_type format_type,
1382                 struct lttng_ust_event *event_param,
1383                 struct lttng_channel *chan)
1384 {
1385         struct lttng_event_enabler *event_enabler;
1386
1387         event_enabler = zmalloc(sizeof(*event_enabler));
1388         if (!event_enabler)
1389                 return NULL;
1390         event_enabler->base.format_type = format_type;
1391         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1392         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1393         memcpy(&event_enabler->base.event_param, event_param,
1394                 sizeof(event_enabler->base.event_param));
1395         event_enabler->chan = chan;
1396         /* ctx left NULL */
1397         event_enabler->base.enabled = 0;
1398         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1399         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1400
1401         return event_enabler;
1402 }
1403
1404 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1405                 struct lttng_event_notifier_group *event_notifier_group,
1406                 enum lttng_enabler_format_type format_type,
1407                 struct lttng_ust_event_notifier *event_notifier_param)
1408 {
1409         struct lttng_event_notifier_enabler *event_notifier_enabler;
1410
1411         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1412         if (!event_notifier_enabler)
1413                 return NULL;
1414         event_notifier_enabler->base.format_type = format_type;
1415         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1416         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1417         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1418
1419         event_notifier_enabler->user_token = event_notifier_param->event.token;
1420         event_notifier_enabler->num_captures = 0;
1421
1422         memcpy(&event_notifier_enabler->base.event_param.name,
1423                 event_notifier_param->event.name,
1424                 sizeof(event_notifier_enabler->base.event_param.name));
1425         event_notifier_enabler->base.event_param.instrumentation =
1426                 event_notifier_param->event.instrumentation;
1427         event_notifier_enabler->base.event_param.loglevel =
1428                 event_notifier_param->event.loglevel;
1429         event_notifier_enabler->base.event_param.loglevel_type =
1430                 event_notifier_param->event.loglevel_type;
1431
1432         event_notifier_enabler->base.enabled = 0;
1433         event_notifier_enabler->group = event_notifier_group;
1434
1435         cds_list_add(&event_notifier_enabler->node,
1436                         &event_notifier_group->enablers_head);
1437
1438         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1439
1440         return event_notifier_enabler;
1441 }
1442
1443 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1444 {
1445         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1446         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1447
1448         return 0;
1449 }
1450
1451 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1452 {
1453         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1454         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1455
1456         return 0;
1457 }
1458
1459 static
1460 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1461                 struct lttng_ust_bytecode_node *bytecode)
1462 {
1463         bytecode->enabler = enabler;
1464         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
1465 }
1466
1467 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1468                 struct lttng_ust_bytecode_node *bytecode)
1469 {
1470         _lttng_enabler_attach_filter_bytecode(
1471                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1472
1473         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1474         return 0;
1475 }
1476
1477 static
1478 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1479                 struct lttng_ust_excluder_node *excluder)
1480 {
1481         excluder->enabler = enabler;
1482         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
1483 }
1484
1485 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1486                 struct lttng_ust_excluder_node *excluder)
1487 {
1488         _lttng_enabler_attach_exclusion(
1489                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1490
1491         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1492         return 0;
1493 }
1494
1495 int lttng_event_notifier_enabler_enable(
1496                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1497 {
1498         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1499         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1500
1501         return 0;
1502 }
1503
1504 int lttng_event_notifier_enabler_disable(
1505                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1506 {
1507         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1508         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1509
1510         return 0;
1511 }
1512
1513 int lttng_event_notifier_enabler_attach_filter_bytecode(
1514                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1515                 struct lttng_ust_bytecode_node *bytecode)
1516 {
1517         _lttng_enabler_attach_filter_bytecode(
1518                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1519                 bytecode);
1520
1521         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1522         return 0;
1523 }
1524
1525 int lttng_event_notifier_enabler_attach_capture_bytecode(
1526                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1527                 struct lttng_ust_bytecode_node *bytecode)
1528 {
1529         bytecode->enabler = lttng_event_notifier_enabler_as_enabler(
1530                         event_notifier_enabler);
1531         cds_list_add_tail(&bytecode->node,
1532                         &event_notifier_enabler->capture_bytecode_head);
1533         event_notifier_enabler->num_captures++;
1534
1535         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1536         return 0;
1537 }
1538
1539 int lttng_event_notifier_enabler_attach_exclusion(
1540                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1541                 struct lttng_ust_excluder_node *excluder)
1542 {
1543         _lttng_enabler_attach_exclusion(
1544                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1545                 excluder);
1546
1547         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1548         return 0;
1549 }
1550
1551 int lttng_attach_context(struct lttng_ust_context *context_param,
1552                 union ust_args *uargs,
1553                 struct lttng_ctx **ctx, struct lttng_session *session)
1554 {
1555         /*
1556          * We cannot attach a context after trace has been started for a
1557          * session because the metadata does not allow expressing this
1558          * information outside of the original channel scope.
1559          */
1560         if (session->been_active)
1561                 return -EPERM;
1562
1563         switch (context_param->ctx) {
1564         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1565                 return lttng_add_pthread_id_to_ctx(ctx);
1566         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1567         {
1568                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1569
1570                 perf_ctx_param = &context_param->u.perf_counter;
1571                 return lttng_add_perf_counter_to_ctx(
1572                         perf_ctx_param->type,
1573                         perf_ctx_param->config,
1574                         perf_ctx_param->name,
1575                         ctx);
1576         }
1577         case LTTNG_UST_CONTEXT_VTID:
1578                 return lttng_add_vtid_to_ctx(ctx);
1579         case LTTNG_UST_CONTEXT_VPID:
1580                 return lttng_add_vpid_to_ctx(ctx);
1581         case LTTNG_UST_CONTEXT_PROCNAME:
1582                 return lttng_add_procname_to_ctx(ctx);
1583         case LTTNG_UST_CONTEXT_IP:
1584                 return lttng_add_ip_to_ctx(ctx);
1585         case LTTNG_UST_CONTEXT_CPU_ID:
1586                 return lttng_add_cpu_id_to_ctx(ctx);
1587         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1588                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1589                         ctx);
1590         case LTTNG_UST_CONTEXT_CGROUP_NS:
1591                 return lttng_add_cgroup_ns_to_ctx(ctx);
1592         case LTTNG_UST_CONTEXT_IPC_NS:
1593                 return lttng_add_ipc_ns_to_ctx(ctx);
1594         case LTTNG_UST_CONTEXT_MNT_NS:
1595                 return lttng_add_mnt_ns_to_ctx(ctx);
1596         case LTTNG_UST_CONTEXT_NET_NS:
1597                 return lttng_add_net_ns_to_ctx(ctx);
1598         case LTTNG_UST_CONTEXT_PID_NS:
1599                 return lttng_add_pid_ns_to_ctx(ctx);
1600         case LTTNG_UST_CONTEXT_TIME_NS:
1601                 return lttng_add_time_ns_to_ctx(ctx);
1602         case LTTNG_UST_CONTEXT_USER_NS:
1603                 return lttng_add_user_ns_to_ctx(ctx);
1604         case LTTNG_UST_CONTEXT_UTS_NS:
1605                 return lttng_add_uts_ns_to_ctx(ctx);
1606         case LTTNG_UST_CONTEXT_VUID:
1607                 return lttng_add_vuid_to_ctx(ctx);
1608         case LTTNG_UST_CONTEXT_VEUID:
1609                 return lttng_add_veuid_to_ctx(ctx);
1610         case LTTNG_UST_CONTEXT_VSUID:
1611                 return lttng_add_vsuid_to_ctx(ctx);
1612         case LTTNG_UST_CONTEXT_VGID:
1613                 return lttng_add_vgid_to_ctx(ctx);
1614         case LTTNG_UST_CONTEXT_VEGID:
1615                 return lttng_add_vegid_to_ctx(ctx);
1616         case LTTNG_UST_CONTEXT_VSGID:
1617                 return lttng_add_vsgid_to_ctx(ctx);
1618         default:
1619                 return -EINVAL;
1620         }
1621 }
1622
1623 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1624                 struct lttng_ust_context *context_param)
1625 {
1626         return -ENOSYS;
1627 }
1628
1629 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1630 {
1631         if (!event_enabler) {
1632                 return;
1633         }
1634         cds_list_del(&event_enabler->node);
1635
1636         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1637
1638         lttng_destroy_context(event_enabler->ctx);
1639         free(event_enabler);
1640 }
1641
1642 /*
1643  * lttng_session_sync_event_enablers should be called just before starting a
1644  * session.
1645  */
1646 static
1647 void lttng_session_sync_event_enablers(struct lttng_session *session)
1648 {
1649         struct lttng_event_enabler *event_enabler;
1650         struct lttng_event *event;
1651
1652         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1653                 lttng_event_enabler_ref_events(event_enabler);
1654         /*
1655          * For each event, if at least one of its enablers is enabled,
1656          * and its channel and session transient states are enabled, we
1657          * enable the event, else we disable it.
1658          */
1659         cds_list_for_each_entry(event, &session->events_head, node) {
1660                 struct lttng_enabler_ref *enabler_ref;
1661                 struct lttng_bytecode_runtime *runtime;
1662                 int enabled = 0, has_enablers_without_bytecode = 0;
1663
1664                 /* Enable events */
1665                 cds_list_for_each_entry(enabler_ref,
1666                                 &event->enablers_ref_head, node) {
1667                         if (enabler_ref->ref->enabled) {
1668                                 enabled = 1;
1669                                 break;
1670                         }
1671                 }
1672                 /*
1673                  * Enabled state is based on union of enablers, with
1674                  * intesection of session and channel transient enable
1675                  * states.
1676                  */
1677                 enabled = enabled && session->tstate && event->chan->tstate;
1678
1679                 CMM_STORE_SHARED(event->enabled, enabled);
1680                 /*
1681                  * Sync tracepoint registration with event enabled
1682                  * state.
1683                  */
1684                 if (enabled) {
1685                         if (!event->registered)
1686                                 register_event(event);
1687                 } else {
1688                         if (event->registered)
1689                                 unregister_event(event);
1690                 }
1691
1692                 /* Check if has enablers without bytecode enabled */
1693                 cds_list_for_each_entry(enabler_ref,
1694                                 &event->enablers_ref_head, node) {
1695                         if (enabler_ref->ref->enabled
1696                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1697                                 has_enablers_without_bytecode = 1;
1698                                 break;
1699                         }
1700                 }
1701                 event->has_enablers_without_bytecode =
1702                         has_enablers_without_bytecode;
1703
1704                 /* Enable filters */
1705                 cds_list_for_each_entry(runtime,
1706                                 &event->filter_bytecode_runtime_head, node) {
1707                         lttng_bytecode_filter_sync_state(runtime);
1708                 }
1709         }
1710         __tracepoint_probe_prune_release_queue();
1711 }
1712
1713 static
1714 void lttng_create_event_notifier_if_missing(
1715                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1716 {
1717         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1718         struct lttng_probe_desc *probe_desc;
1719         struct cds_list_head *probe_list;
1720         int i;
1721
1722         probe_list = lttng_get_probe_list_head();
1723
1724         cds_list_for_each_entry(probe_desc, probe_list, head) {
1725                 for (i = 0; i < probe_desc->nr_events; i++) {
1726                         int ret;
1727                         bool found = false;
1728                         const struct lttng_event_desc *desc;
1729                         struct lttng_event_notifier *event_notifier;
1730                         struct cds_hlist_head *head;
1731                         struct cds_hlist_node *node;
1732
1733                         desc = probe_desc->event_desc[i];
1734
1735                         if (!lttng_desc_match_enabler(desc,
1736                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1737                                 continue;
1738
1739                         /*
1740                          * Given the current event_notifier group, get the bucket that
1741                          * the target event_notifier would be if it was already
1742                          * created.
1743                          */
1744                         head = borrow_hash_table_bucket(
1745                                 event_notifier_group->event_notifiers_ht.table,
1746                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1747
1748                         cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
1749                                 /*
1750                                  * Check if event_notifier already exists by checking
1751                                  * if the event_notifier and enabler share the same
1752                                  * description and id.
1753                                  */
1754                                 if (event_notifier->desc == desc &&
1755                                                 event_notifier->user_token == event_notifier_enabler->user_token) {
1756                                         found = true;
1757                                         break;
1758                                 }
1759                         }
1760
1761                         if (found)
1762                                 continue;
1763
1764                         /*
1765                          * We need to create a event_notifier for this event probe.
1766                          */
1767                         ret = lttng_event_notifier_create(desc,
1768                                 event_notifier_enabler->user_token,
1769                                 event_notifier_group);
1770                         if (ret) {
1771                                 DBG("Unable to create event_notifier %s, error %d\n",
1772                                         probe_desc->event_desc[i]->name, ret);
1773                         }
1774                 }
1775         }
1776 }
1777
1778 /*
1779  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1780  */
1781 static
1782 int lttng_event_notifier_enabler_ref_event_notifiers(
1783                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1784 {
1785         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1786         struct lttng_event_notifier *event_notifier;
1787
1788          /*
1789           * Only try to create event_notifiers for enablers that are enabled, the user
1790           * might still be attaching filter or exclusion to the
1791           * event_notifier_enabler.
1792           */
1793         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1794                 goto end;
1795
1796         /* First, ensure that probe event_notifiers are created for this enabler. */
1797         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1798
1799         /* Link the created event_notifier with its associated enabler. */
1800         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1801                 struct lttng_enabler_ref *enabler_ref;
1802
1803                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
1804                         continue;
1805
1806                 enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
1807                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1808                 if (!enabler_ref) {
1809                         /*
1810                          * If no backward ref, create it.
1811                          * Add backward ref from event_notifier to enabler.
1812                          */
1813                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1814                         if (!enabler_ref)
1815                                 return -ENOMEM;
1816
1817                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1818                                 event_notifier_enabler);
1819                         cds_list_add(&enabler_ref->node,
1820                                 &event_notifier->enablers_ref_head);
1821                 }
1822
1823                 /*
1824                  * Link filter bytecodes if not linked yet.
1825                  */
1826                 lttng_enabler_link_bytecode(event_notifier->desc,
1827                         &event_notifier_group->ctx,
1828                         &event_notifier->filter_bytecode_runtime_head,
1829                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1830
1831                 /*
1832                  * Link capture bytecodes if not linked yet.
1833                  */
1834                 lttng_enabler_link_bytecode(event_notifier->desc,
1835                         &event_notifier_group->ctx, &event_notifier->capture_bytecode_runtime_head,
1836                         &event_notifier_enabler->capture_bytecode_head);
1837
1838                 event_notifier->num_captures = event_notifier_enabler->num_captures;
1839         }
1840 end:
1841         return 0;
1842 }
1843
1844 static
1845 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1846 {
1847         struct lttng_event_notifier_enabler *event_notifier_enabler;
1848         struct lttng_event_notifier *event_notifier;
1849
1850         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1851                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1852
1853         /*
1854          * For each event_notifier, if at least one of its enablers is enabled,
1855          * we enable the event_notifier, else we disable it.
1856          */
1857         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1858                 struct lttng_enabler_ref *enabler_ref;
1859                 struct lttng_bytecode_runtime *runtime;
1860                 int enabled = 0, has_enablers_without_bytecode = 0;
1861
1862                 /* Enable event_notifiers */
1863                 cds_list_for_each_entry(enabler_ref,
1864                                 &event_notifier->enablers_ref_head, node) {
1865                         if (enabler_ref->ref->enabled) {
1866                                 enabled = 1;
1867                                 break;
1868                         }
1869                 }
1870
1871                 CMM_STORE_SHARED(event_notifier->enabled, enabled);
1872                 /*
1873                  * Sync tracepoint registration with event_notifier enabled
1874                  * state.
1875                  */
1876                 if (enabled) {
1877                         if (!event_notifier->registered)
1878                                 register_event_notifier(event_notifier);
1879                 } else {
1880                         if (event_notifier->registered)
1881                                 unregister_event_notifier(event_notifier);
1882                 }
1883
1884                 /* Check if has enablers without bytecode enabled */
1885                 cds_list_for_each_entry(enabler_ref,
1886                                 &event_notifier->enablers_ref_head, node) {
1887                         if (enabler_ref->ref->enabled
1888                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1889                                 has_enablers_without_bytecode = 1;
1890                                 break;
1891                         }
1892                 }
1893                 event_notifier->has_enablers_without_bytecode =
1894                         has_enablers_without_bytecode;
1895
1896                 /* Enable filters */
1897                 cds_list_for_each_entry(runtime,
1898                                 &event_notifier->filter_bytecode_runtime_head, node) {
1899                         lttng_bytecode_filter_sync_state(runtime);
1900                 }
1901
1902                 /* Enable captures. */
1903                 cds_list_for_each_entry(runtime,
1904                                 &event_notifier->capture_bytecode_runtime_head, node) {
1905                         lttng_bytecode_capture_sync_state(runtime);
1906                 }
1907         }
1908         __tracepoint_probe_prune_release_queue();
1909 }
1910
1911 /*
1912  * Apply enablers to session events, adding events to session if need
1913  * be. It is required after each modification applied to an active
1914  * session, and right before session "start".
1915  * "lazy" sync means we only sync if required.
1916  */
1917 static
1918 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1919 {
1920         /* We can skip if session is not active */
1921         if (!session->active)
1922                 return;
1923         lttng_session_sync_event_enablers(session);
1924 }
1925
1926 /*
1927  * Update all sessions with the given app context.
1928  * Called with ust lock held.
1929  * This is invoked when an application context gets loaded/unloaded. It
1930  * ensures the context callbacks are in sync with the application
1931  * context (either app context callbacks, or dummy callbacks).
1932  */
1933 void lttng_ust_context_set_session_provider(const char *name,
1934                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1935                 void (*record)(struct lttng_ctx_field *field,
1936                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1937                         struct lttng_channel *chan),
1938                 void (*get_value)(struct lttng_ctx_field *field,
1939                         struct lttng_ctx_value *value))
1940 {
1941         struct lttng_session *session;
1942
1943         cds_list_for_each_entry(session, &sessions, node) {
1944                 struct lttng_channel *chan;
1945                 struct lttng_event *event;
1946                 int ret;
1947
1948                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1949                                 name, get_size, record, get_value);
1950                 if (ret)
1951                         abort();
1952                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1953                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1954                                         name, get_size, record, get_value);
1955                         if (ret)
1956                                 abort();
1957                 }
1958                 cds_list_for_each_entry(event, &session->events_head, node) {
1959                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1960                                         name, get_size, record, get_value);
1961                         if (ret)
1962                                 abort();
1963                 }
1964         }
1965 }
1966
1967 /*
1968  * Update all event_notifier groups with the given app context.
1969  * Called with ust lock held.
1970  * This is invoked when an application context gets loaded/unloaded. It
1971  * ensures the context callbacks are in sync with the application
1972  * context (either app context callbacks, or dummy callbacks).
1973  */
1974 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
1975                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1976                 void (*record)(struct lttng_ctx_field *field,
1977                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1978                         struct lttng_channel *chan),
1979                 void (*get_value)(struct lttng_ctx_field *field,
1980                         struct lttng_ctx_value *value))
1981 {
1982         struct lttng_event_notifier_group *event_notifier_group;
1983
1984         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1985                 int ret;
1986
1987                 ret = lttng_ust_context_set_provider_rcu(
1988                                 &event_notifier_group->ctx,
1989                                 name, get_size, record, get_value);
1990                 if (ret)
1991                         abort();
1992         }
1993 }