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, uint64_t error_counter_index,
 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         event_notifier->error_counter_index = error_counter_index;
 868
 869         /* Event notifier will be enabled by enabler sync. */
 870         event_notifier->enabled = 0;
 871         event_notifier->registered = 0;
 872
 873         CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
 874         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 875         CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
 876         event_notifier->desc = desc;
 877
 878         cds_list_add(&event_notifier->node,
 879                         &event_notifier_group->event_notifiers_head);
 880         cds_hlist_add_head(&event_notifier->hlist, head);
 881
 882         return 0;
 883
 884 error:
 885         return ret;
 886 }
 887
 888 static
 889 void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
 890 {
 891         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 892
 893         /* Remove from event_notifier list. */
 894         cds_list_del(&event_notifier->node);
 895         /* Remove from event_notifier hash table. */
 896         cds_hlist_del(&event_notifier->hlist);
 897
 898         lttng_free_event_notifier_filter_runtime(event_notifier);
 899
 900         /* Free event_notifier enabler refs */
 901         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 902                         &event_notifier->enablers_ref_head, node)
 903                 free(enabler_ref);
 904         free(event_notifier);
 905 }
 906
 907 static
 908 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 909                 struct lttng_enabler *enabler)
 910 {
 911         int loglevel = 0;
 912         unsigned int has_loglevel = 0;
 913
 914         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 915         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 916                         desc->name, SIZE_MAX))
 917                 return 0;
 918         if (desc->loglevel) {
 919                 loglevel = *(*desc->loglevel);
 920                 has_loglevel = 1;
 921         }
 922         if (!lttng_loglevel_match(loglevel,
 923                         has_loglevel,
 924                         enabler->event_param.loglevel_type,
 925                         enabler->event_param.loglevel))
 926                 return 0;
 927         return 1;
 928 }
 929
 930 static
 931 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 932                 struct lttng_enabler *enabler)
 933 {
 934         int loglevel = 0;
 935         unsigned int has_loglevel = 0;
 936
 937         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 938         if (strcmp(desc->name, enabler->event_param.name))
 939                 return 0;
 940         if (desc->loglevel) {
 941                 loglevel = *(*desc->loglevel);
 942                 has_loglevel = 1;
 943         }
 944         if (!lttng_loglevel_match(loglevel,
 945                         has_loglevel,
 946                         enabler->event_param.loglevel_type,
 947                         enabler->event_param.loglevel))
 948                 return 0;
 949         return 1;
 950 }
 951
 952 static
 953 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 954                 struct lttng_enabler *enabler)
 955 {
 956         switch (enabler->format_type) {
 957         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 958         {
 959                 struct lttng_ust_excluder_node *excluder;
 960
 961                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 962                         return 0;
 963                 }
 964
 965                 /*
 966                  * If the matching event matches with an excluder,
 967                  * return 'does not match'
 968                  */
 969                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 970                         int count;
 971
 972                         for (count = 0; count < excluder->excluder.count; count++) {
 973                                 int len;
 974                                 char *excluder_name;
 975
 976                                 excluder_name = (char *) (excluder->excluder.names)
 977                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 978                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 979                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 980                                         return 0;
 981                         }
 982                 }
 983                 return 1;
 984         }
 985         case LTTNG_ENABLER_FORMAT_EVENT:
 986                 return lttng_desc_match_event_enabler(desc, enabler);
 987         default:
 988                 return -EINVAL;
 989         }
 990 }
 991
 992 static
 993 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 994                 struct lttng_event *event)
 995 {
 996         if (lttng_desc_match_enabler(event->desc,
 997                         lttng_event_enabler_as_enabler(event_enabler))
 998                         && event->chan == event_enabler->chan)
 999                 return 1;
1000         else
1001                 return 0;
1002 }
1003
1004 static
1005 int lttng_event_notifier_enabler_match_event_notifier(
1006                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1007                 struct lttng_event_notifier *event_notifier)
1008 {
1009         int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
1010                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1011
1012         if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
1013                         event_notifier->user_token == event_notifier_enabler->user_token)
1014                 return 1;
1015         else
1016                 return 0;
1017 }
1018
1019 static
1020 struct lttng_enabler_ref *lttng_enabler_ref(
1021                 struct cds_list_head *enabler_ref_list,
1022                 struct lttng_enabler *enabler)
1023 {
1024         struct lttng_enabler_ref *enabler_ref;
1025
1026         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1027                 if (enabler_ref->ref == enabler)
1028                         return enabler_ref;
1029         }
1030         return NULL;
1031 }
1032
1033 /*
1034  * Create struct lttng_event if it is missing and present in the list of
1035  * tracepoint probes.
1036  */
1037 static
1038 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1039 {
1040         struct lttng_session *session = event_enabler->chan->session;
1041         struct lttng_probe_desc *probe_desc;
1042         const struct lttng_event_desc *desc;
1043         struct lttng_event *event;
1044         int i;
1045         struct cds_list_head *probe_list;
1046
1047         probe_list = lttng_get_probe_list_head();
1048         /*
1049          * For each probe event, if we find that a probe event matches
1050          * our enabler, create an associated lttng_event if not
1051          * already present.
1052          */
1053         cds_list_for_each_entry(probe_desc, probe_list, head) {
1054                 for (i = 0; i < probe_desc->nr_events; i++) {
1055                         int ret;
1056                         bool found = false;
1057                         struct cds_hlist_head *head;
1058                         struct cds_hlist_node *node;
1059
1060                         desc = probe_desc->event_desc[i];
1061                         if (!lttng_desc_match_enabler(desc,
1062                                         lttng_event_enabler_as_enabler(event_enabler)))
1063                                 continue;
1064
1065                         head = borrow_hash_table_bucket(
1066                                 session->events_ht.table,
1067                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1068
1069                         cds_hlist_for_each_entry(event, node, head, hlist) {
1070                                 if (event->desc == desc
1071                                                 && event->chan == event_enabler->chan) {
1072                                         found = true;
1073                                         break;
1074                                 }
1075                         }
1076                         if (found)
1077                                 continue;
1078
1079                         /*
1080                          * We need to create an event for this
1081                          * event probe.
1082                          */
1083                         ret = lttng_event_create(probe_desc->event_desc[i],
1084                                         event_enabler->chan);
1085                         if (ret) {
1086                                 DBG("Unable to create event %s, error %d\n",
1087                                         probe_desc->event_desc[i]->name, ret);
1088                         }
1089                 }
1090         }
1091 }
1092
1093 static
1094 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1095                 void (*event_func)(struct lttng_session *session,
1096                         struct lttng_event *event),
1097                 void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
1098 {
1099         struct cds_hlist_node *node, *tmp_node;
1100         struct cds_list_head *sessionsp;
1101         unsigned int i;
1102
1103         /* Get handle on list of sessions. */
1104         sessionsp = _lttng_get_sessions();
1105
1106         /*
1107          * Iterate over all events in the probe provider descriptions and
1108          * sessions to queue the unregistration of the events.
1109          */
1110         for (i = 0; i < provider_desc->nr_events; i++) {
1111                 const struct lttng_event_desc *event_desc;
1112                 struct lttng_event_notifier_group *event_notifier_group;
1113                 struct lttng_event_notifier *event_notifier;
1114                 struct lttng_session *session;
1115                 struct cds_hlist_head *head;
1116                 struct lttng_event *event;
1117
1118                 event_desc = provider_desc->event_desc[i];
1119
1120                 /*
1121                  * Iterate over all session to find the current event
1122                  * description.
1123                  */
1124                 cds_list_for_each_entry(session, sessionsp, node) {
1125                         /*
1126                          * Get the list of events in the hashtable bucket and
1127                          * iterate to find the event matching this descriptor.
1128                          */
1129                         head = borrow_hash_table_bucket(
1130                                 session->events_ht.table,
1131                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1132
1133                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1134                                 if (event_desc == event->desc) {
1135                                         event_func(session, event);
1136                                         break;
1137                                 }
1138                         }
1139                 }
1140
1141                 /*
1142                  * Iterate over all event_notifier groups to find the current event
1143                  * description.
1144                  */
1145                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1146                         /*
1147                          * Get the list of event_notifiers in the hashtable bucket and
1148                          * iterate to find the event_notifier matching this
1149                          * descriptor.
1150                          */
1151                         head = borrow_hash_table_bucket(
1152                                 event_notifier_group->event_notifiers_ht.table,
1153                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1154
1155                         cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
1156                                 if (event_desc == event_notifier->desc) {
1157                                         event_notifier_func(event_notifier);
1158                                         break;
1159                                 }
1160                         }
1161                 }
1162         }
1163 }
1164
1165 static
1166 void _unregister_event(struct lttng_session *session,
1167                 struct lttng_event *event)
1168 {
1169         _lttng_event_unregister(event);
1170 }
1171
1172 static
1173 void _event_enum_destroy(struct lttng_session *session,
1174                 struct lttng_event *event)
1175 {
1176         unsigned int i;
1177
1178         /* Destroy enums of the current event. */
1179         for (i = 0; i < event->desc->nr_fields; i++) {
1180                 const struct lttng_enum_desc *enum_desc;
1181                 const struct lttng_event_field *field;
1182                 struct lttng_enum *curr_enum;
1183
1184                 field = &(event->desc->fields[i]);
1185                 switch (field->type.atype) {
1186                 case atype_enum:
1187                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1188                         break;
1189                 case atype_enum_nestable:
1190                         enum_desc = field->type.u.enum_nestable.desc;
1191                         break;
1192                 default:
1193                         continue;
1194                 }
1195
1196                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1197                 if (curr_enum) {
1198                         _lttng_enum_destroy(curr_enum);
1199                 }
1200         }
1201
1202         /* Destroy event. */
1203         _lttng_event_destroy(event);
1204 }
1205
1206 /*
1207  * Iterate over all the UST sessions to unregister and destroy all probes from
1208  * the probe provider descriptor received as argument. Must me called with the
1209  * ust_lock held.
1210  */
1211 void lttng_probe_provider_unregister_events(
1212                 struct lttng_probe_desc *provider_desc)
1213 {
1214         /*
1215          * Iterate over all events in the probe provider descriptions and sessions
1216          * to queue the unregistration of the events.
1217          */
1218         probe_provider_event_for_each(provider_desc, _unregister_event,
1219                 _lttng_event_notifier_unregister);
1220
1221         /* Wait for grace period. */
1222         synchronize_trace();
1223         /* Prune the unregistration queue. */
1224         __tracepoint_probe_prune_release_queue();
1225
1226         /*
1227          * It is now safe to destroy the events and remove them from the event list
1228          * and hashtables.
1229          */
1230         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1231                 _lttng_event_notifier_destroy);
1232 }
1233
1234 /*
1235  * Create events associated with an event enabler (if not already present),
1236  * and add backward reference from the event to the enabler.
1237  */
1238 static
1239 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1240 {
1241         struct lttng_session *session = event_enabler->chan->session;
1242         struct lttng_event *event;
1243
1244         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1245                 goto end;
1246
1247         /* First ensure that probe events are created for this enabler. */
1248         lttng_create_event_if_missing(event_enabler);
1249
1250         /* For each event matching enabler in session event list. */
1251         cds_list_for_each_entry(event, &session->events_head, node) {
1252                 struct lttng_enabler_ref *enabler_ref;
1253
1254                 if (!lttng_event_enabler_match_event(event_enabler, event))
1255                         continue;
1256
1257                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1258                         lttng_event_enabler_as_enabler(event_enabler));
1259                 if (!enabler_ref) {
1260                         /*
1261                          * If no backward ref, create it.
1262                          * Add backward ref from event to enabler.
1263                          */
1264                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1265                         if (!enabler_ref)
1266                                 return -ENOMEM;
1267                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1268                                 event_enabler);
1269                         cds_list_add(&enabler_ref->node,
1270                                 &event->enablers_ref_head);
1271                 }
1272
1273                 /*
1274                  * Link filter bytecodes if not linked yet.
1275                  */
1276                 lttng_enabler_link_bytecode(event->desc,
1277                         &session->ctx,
1278                         &event->filter_bytecode_runtime_head,
1279                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1280
1281                 /* TODO: merge event context. */
1282         }
1283 end:
1284         return 0;
1285 }
1286
1287 /*
1288  * Called at library load: connect the probe on all enablers matching
1289  * this event.
1290  * Called with session mutex held.
1291  */
1292 int lttng_fix_pending_events(void)
1293 {
1294         struct lttng_session *session;
1295
1296         cds_list_for_each_entry(session, &sessions, node) {
1297                 lttng_session_lazy_sync_event_enablers(session);
1298         }
1299         return 0;
1300 }
1301
1302 int lttng_fix_pending_event_notifiers(void)
1303 {
1304         struct lttng_event_notifier_group *event_notifier_group;
1305
1306         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1307                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1308         }
1309         return 0;
1310 }
1311
1312 /*
1313  * For each session of the owner thread, execute pending statedump.
1314  * Only dump state for the sessions owned by the caller thread, because
1315  * we don't keep ust_lock across the entire iteration.
1316  */
1317 void lttng_handle_pending_statedump(void *owner)
1318 {
1319         struct lttng_session *session;
1320
1321         /* Execute state dump */
1322         do_lttng_ust_statedump(owner);
1323
1324         /* Clear pending state dump */
1325         if (ust_lock()) {
1326                 goto end;
1327         }
1328         cds_list_for_each_entry(session, &sessions, node) {
1329                 if (session->owner != owner)
1330                         continue;
1331                 if (!session->statedump_pending)
1332                         continue;
1333                 session->statedump_pending = 0;
1334         }
1335 end:
1336         ust_unlock();
1337         return;
1338 }
1339
1340 /*
1341  * Only used internally at session destruction.
1342  */
1343 static
1344 void _lttng_event_destroy(struct lttng_event *event)
1345 {
1346         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1347
1348         /* Remove from event list. */
1349         cds_list_del(&event->node);
1350         /* Remove from event hash table. */
1351         cds_hlist_del(&event->hlist);
1352
1353         lttng_destroy_context(event->ctx);
1354         lttng_free_event_filter_runtime(event);
1355         /* Free event enabler refs */
1356         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1357                         &event->enablers_ref_head, node)
1358                 free(enabler_ref);
1359         free(event);
1360 }
1361
1362 static
1363 void _lttng_enum_destroy(struct lttng_enum *_enum)
1364 {
1365         cds_list_del(&_enum->node);
1366         cds_hlist_del(&_enum->hlist);
1367         free(_enum);
1368 }
1369
1370 void lttng_ust_events_exit(void)
1371 {
1372         struct lttng_session *session, *tmpsession;
1373
1374         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1375                 lttng_session_destroy(session);
1376 }
1377
1378 /*
1379  * Enabler management.
1380  */
1381 struct lttng_event_enabler *lttng_event_enabler_create(
1382                 enum lttng_enabler_format_type format_type,
1383                 struct lttng_ust_event *event_param,
1384                 struct lttng_channel *chan)
1385 {
1386         struct lttng_event_enabler *event_enabler;
1387
1388         event_enabler = zmalloc(sizeof(*event_enabler));
1389         if (!event_enabler)
1390                 return NULL;
1391         event_enabler->base.format_type = format_type;
1392         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1393         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1394         memcpy(&event_enabler->base.event_param, event_param,
1395                 sizeof(event_enabler->base.event_param));
1396         event_enabler->chan = chan;
1397         /* ctx left NULL */
1398         event_enabler->base.enabled = 0;
1399         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1400         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1401
1402         return event_enabler;
1403 }
1404
1405 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1406                 struct lttng_event_notifier_group *event_notifier_group,
1407                 enum lttng_enabler_format_type format_type,
1408                 struct lttng_ust_event_notifier *event_notifier_param)
1409 {
1410         struct lttng_event_notifier_enabler *event_notifier_enabler;
1411
1412         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1413         if (!event_notifier_enabler)
1414                 return NULL;
1415         event_notifier_enabler->base.format_type = format_type;
1416         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1417         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1418         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1419
1420         event_notifier_enabler->user_token = event_notifier_param->event.token;
1421         event_notifier_enabler->num_captures = 0;
1422
1423         memcpy(&event_notifier_enabler->base.event_param.name,
1424                 event_notifier_param->event.name,
1425                 sizeof(event_notifier_enabler->base.event_param.name));
1426         event_notifier_enabler->base.event_param.instrumentation =
1427                 event_notifier_param->event.instrumentation;
1428         event_notifier_enabler->base.event_param.loglevel =
1429                 event_notifier_param->event.loglevel;
1430         event_notifier_enabler->base.event_param.loglevel_type =
1431                 event_notifier_param->event.loglevel_type;
1432
1433         event_notifier_enabler->base.enabled = 0;
1434         event_notifier_enabler->group = event_notifier_group;
1435
1436         cds_list_add(&event_notifier_enabler->node,
1437                         &event_notifier_group->enablers_head);
1438
1439         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1440
1441         return event_notifier_enabler;
1442 }
1443
1444 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1445 {
1446         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1447         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1448
1449         return 0;
1450 }
1451
1452 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1453 {
1454         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1455         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1456
1457         return 0;
1458 }
1459
1460 static
1461 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1462                 struct lttng_ust_bytecode_node *bytecode)
1463 {
1464         bytecode->enabler = enabler;
1465         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
1466 }
1467
1468 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1469                 struct lttng_ust_bytecode_node *bytecode)
1470 {
1471         _lttng_enabler_attach_filter_bytecode(
1472                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1473
1474         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1475         return 0;
1476 }
1477
1478 static
1479 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1480                 struct lttng_ust_excluder_node *excluder)
1481 {
1482         excluder->enabler = enabler;
1483         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
1484 }
1485
1486 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1487                 struct lttng_ust_excluder_node *excluder)
1488 {
1489         _lttng_enabler_attach_exclusion(
1490                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1491
1492         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1493         return 0;
1494 }
1495
1496 int lttng_event_notifier_enabler_enable(
1497                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1498 {
1499         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1500         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1501
1502         return 0;
1503 }
1504
1505 int lttng_event_notifier_enabler_disable(
1506                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1507 {
1508         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1509         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1510
1511         return 0;
1512 }
1513
1514 int lttng_event_notifier_enabler_attach_filter_bytecode(
1515                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1516                 struct lttng_ust_bytecode_node *bytecode)
1517 {
1518         _lttng_enabler_attach_filter_bytecode(
1519                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1520                 bytecode);
1521
1522         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1523         return 0;
1524 }
1525
1526 int lttng_event_notifier_enabler_attach_capture_bytecode(
1527                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1528                 struct lttng_ust_bytecode_node *bytecode)
1529 {
1530         bytecode->enabler = lttng_event_notifier_enabler_as_enabler(
1531                         event_notifier_enabler);
1532         cds_list_add_tail(&bytecode->node,
1533                         &event_notifier_enabler->capture_bytecode_head);
1534         event_notifier_enabler->num_captures++;
1535
1536         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1537         return 0;
1538 }
1539
1540 int lttng_event_notifier_enabler_attach_exclusion(
1541                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1542                 struct lttng_ust_excluder_node *excluder)
1543 {
1544         _lttng_enabler_attach_exclusion(
1545                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1546                 excluder);
1547
1548         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1549         return 0;
1550 }
1551
1552 int lttng_attach_context(struct lttng_ust_context *context_param,
1553                 union ust_args *uargs,
1554                 struct lttng_ctx **ctx, struct lttng_session *session)
1555 {
1556         /*
1557          * We cannot attach a context after trace has been started for a
1558          * session because the metadata does not allow expressing this
1559          * information outside of the original channel scope.
1560          */
1561         if (session->been_active)
1562                 return -EPERM;
1563
1564         switch (context_param->ctx) {
1565         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1566                 return lttng_add_pthread_id_to_ctx(ctx);
1567         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1568         {
1569                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1570
1571                 perf_ctx_param = &context_param->u.perf_counter;
1572                 return lttng_add_perf_counter_to_ctx(
1573                         perf_ctx_param->type,
1574                         perf_ctx_param->config,
1575                         perf_ctx_param->name,
1576                         ctx);
1577         }
1578         case LTTNG_UST_CONTEXT_VTID:
1579                 return lttng_add_vtid_to_ctx(ctx);
1580         case LTTNG_UST_CONTEXT_VPID:
1581                 return lttng_add_vpid_to_ctx(ctx);
1582         case LTTNG_UST_CONTEXT_PROCNAME:
1583                 return lttng_add_procname_to_ctx(ctx);
1584         case LTTNG_UST_CONTEXT_IP:
1585                 return lttng_add_ip_to_ctx(ctx);
1586         case LTTNG_UST_CONTEXT_CPU_ID:
1587                 return lttng_add_cpu_id_to_ctx(ctx);
1588         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1589                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1590                         ctx);
1591         case LTTNG_UST_CONTEXT_CGROUP_NS:
1592                 return lttng_add_cgroup_ns_to_ctx(ctx);
1593         case LTTNG_UST_CONTEXT_IPC_NS:
1594                 return lttng_add_ipc_ns_to_ctx(ctx);
1595         case LTTNG_UST_CONTEXT_MNT_NS:
1596                 return lttng_add_mnt_ns_to_ctx(ctx);
1597         case LTTNG_UST_CONTEXT_NET_NS:
1598                 return lttng_add_net_ns_to_ctx(ctx);
1599         case LTTNG_UST_CONTEXT_PID_NS:
1600                 return lttng_add_pid_ns_to_ctx(ctx);
1601         case LTTNG_UST_CONTEXT_TIME_NS:
1602                 return lttng_add_time_ns_to_ctx(ctx);
1603         case LTTNG_UST_CONTEXT_USER_NS:
1604                 return lttng_add_user_ns_to_ctx(ctx);
1605         case LTTNG_UST_CONTEXT_UTS_NS:
1606                 return lttng_add_uts_ns_to_ctx(ctx);
1607         case LTTNG_UST_CONTEXT_VUID:
1608                 return lttng_add_vuid_to_ctx(ctx);
1609         case LTTNG_UST_CONTEXT_VEUID:
1610                 return lttng_add_veuid_to_ctx(ctx);
1611         case LTTNG_UST_CONTEXT_VSUID:
1612                 return lttng_add_vsuid_to_ctx(ctx);
1613         case LTTNG_UST_CONTEXT_VGID:
1614                 return lttng_add_vgid_to_ctx(ctx);
1615         case LTTNG_UST_CONTEXT_VEGID:
1616                 return lttng_add_vegid_to_ctx(ctx);
1617         case LTTNG_UST_CONTEXT_VSGID:
1618                 return lttng_add_vsgid_to_ctx(ctx);
1619         default:
1620                 return -EINVAL;
1621         }
1622 }
1623
1624 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1625                 struct lttng_ust_context *context_param)
1626 {
1627         return -ENOSYS;
1628 }
1629
1630 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1631 {
1632         if (!event_enabler) {
1633                 return;
1634         }
1635         cds_list_del(&event_enabler->node);
1636
1637         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1638
1639         lttng_destroy_context(event_enabler->ctx);
1640         free(event_enabler);
1641 }
1642
1643 /*
1644  * lttng_session_sync_event_enablers should be called just before starting a
1645  * session.
1646  */
1647 static
1648 void lttng_session_sync_event_enablers(struct lttng_session *session)
1649 {
1650         struct lttng_event_enabler *event_enabler;
1651         struct lttng_event *event;
1652
1653         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1654                 lttng_event_enabler_ref_events(event_enabler);
1655         /*
1656          * For each event, if at least one of its enablers is enabled,
1657          * and its channel and session transient states are enabled, we
1658          * enable the event, else we disable it.
1659          */
1660         cds_list_for_each_entry(event, &session->events_head, node) {
1661                 struct lttng_enabler_ref *enabler_ref;
1662                 struct lttng_bytecode_runtime *runtime;
1663                 int enabled = 0, has_enablers_without_bytecode = 0;
1664
1665                 /* Enable events */
1666                 cds_list_for_each_entry(enabler_ref,
1667                                 &event->enablers_ref_head, node) {
1668                         if (enabler_ref->ref->enabled) {
1669                                 enabled = 1;
1670                                 break;
1671                         }
1672                 }
1673                 /*
1674                  * Enabled state is based on union of enablers, with
1675                  * intesection of session and channel transient enable
1676                  * states.
1677                  */
1678                 enabled = enabled && session->tstate && event->chan->tstate;
1679
1680                 CMM_STORE_SHARED(event->enabled, enabled);
1681                 /*
1682                  * Sync tracepoint registration with event enabled
1683                  * state.
1684                  */
1685                 if (enabled) {
1686                         if (!event->registered)
1687                                 register_event(event);
1688                 } else {
1689                         if (event->registered)
1690                                 unregister_event(event);
1691                 }
1692
1693                 /* Check if has enablers without bytecode enabled */
1694                 cds_list_for_each_entry(enabler_ref,
1695                                 &event->enablers_ref_head, node) {
1696                         if (enabler_ref->ref->enabled
1697                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1698                                 has_enablers_without_bytecode = 1;
1699                                 break;
1700                         }
1701                 }
1702                 event->has_enablers_without_bytecode =
1703                         has_enablers_without_bytecode;
1704
1705                 /* Enable filters */
1706                 cds_list_for_each_entry(runtime,
1707                                 &event->filter_bytecode_runtime_head, node) {
1708                         lttng_bytecode_filter_sync_state(runtime);
1709                 }
1710         }
1711         __tracepoint_probe_prune_release_queue();
1712 }
1713
1714 static
1715 void lttng_create_event_notifier_if_missing(
1716                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1717 {
1718         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1719         struct lttng_probe_desc *probe_desc;
1720         struct cds_list_head *probe_list;
1721         int i;
1722
1723         probe_list = lttng_get_probe_list_head();
1724
1725         cds_list_for_each_entry(probe_desc, probe_list, head) {
1726                 for (i = 0; i < probe_desc->nr_events; i++) {
1727                         int ret;
1728                         bool found = false;
1729                         const struct lttng_event_desc *desc;
1730                         struct lttng_event_notifier *event_notifier;
1731                         struct cds_hlist_head *head;
1732                         struct cds_hlist_node *node;
1733
1734                         desc = probe_desc->event_desc[i];
1735
1736                         if (!lttng_desc_match_enabler(desc,
1737                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1738                                 continue;
1739
1740                         /*
1741                          * Given the current event_notifier group, get the bucket that
1742                          * the target event_notifier would be if it was already
1743                          * created.
1744                          */
1745                         head = borrow_hash_table_bucket(
1746                                 event_notifier_group->event_notifiers_ht.table,
1747                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1748
1749                         cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
1750                                 /*
1751                                  * Check if event_notifier already exists by checking
1752                                  * if the event_notifier and enabler share the same
1753                                  * description and id.
1754                                  */
1755                                 if (event_notifier->desc == desc &&
1756                                                 event_notifier->user_token == event_notifier_enabler->user_token) {
1757                                         found = true;
1758                                         break;
1759                                 }
1760                         }
1761
1762                         if (found)
1763                                 continue;
1764
1765                         /*
1766                          * We need to create a event_notifier for this event probe.
1767                          */
1768                         ret = lttng_event_notifier_create(desc,
1769                                 event_notifier_enabler->user_token,
1770                                 event_notifier_enabler->error_counter_index,
1771                                 event_notifier_group);
1772                         if (ret) {
1773                                 DBG("Unable to create event_notifier %s, error %d\n",
1774                                         probe_desc->event_desc[i]->name, ret);
1775                         }
1776                 }
1777         }
1778 }
1779
1780 /*
1781  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1782  */
1783 static
1784 int lttng_event_notifier_enabler_ref_event_notifiers(
1785                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1786 {
1787         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1788         struct lttng_event_notifier *event_notifier;
1789
1790          /*
1791           * Only try to create event_notifiers for enablers that are enabled, the user
1792           * might still be attaching filter or exclusion to the
1793           * event_notifier_enabler.
1794           */
1795         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1796                 goto end;
1797
1798         /* First, ensure that probe event_notifiers are created for this enabler. */
1799         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1800
1801         /* Link the created event_notifier with its associated enabler. */
1802         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1803                 struct lttng_enabler_ref *enabler_ref;
1804
1805                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
1806                         continue;
1807
1808                 enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
1809                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1810                 if (!enabler_ref) {
1811                         /*
1812                          * If no backward ref, create it.
1813                          * Add backward ref from event_notifier to enabler.
1814                          */
1815                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1816                         if (!enabler_ref)
1817                                 return -ENOMEM;
1818
1819                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1820                                 event_notifier_enabler);
1821                         cds_list_add(&enabler_ref->node,
1822                                 &event_notifier->enablers_ref_head);
1823                 }
1824
1825                 /*
1826                  * Link filter bytecodes if not linked yet.
1827                  */
1828                 lttng_enabler_link_bytecode(event_notifier->desc,
1829                         &event_notifier_group->ctx,
1830                         &event_notifier->filter_bytecode_runtime_head,
1831                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1832
1833                 /*
1834                  * Link capture bytecodes if not linked yet.
1835                  */
1836                 lttng_enabler_link_bytecode(event_notifier->desc,
1837                         &event_notifier_group->ctx, &event_notifier->capture_bytecode_runtime_head,
1838                         &event_notifier_enabler->capture_bytecode_head);
1839
1840                 event_notifier->num_captures = event_notifier_enabler->num_captures;
1841         }
1842 end:
1843         return 0;
1844 }
1845
1846 static
1847 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1848 {
1849         struct lttng_event_notifier_enabler *event_notifier_enabler;
1850         struct lttng_event_notifier *event_notifier;
1851
1852         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1853                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1854
1855         /*
1856          * For each event_notifier, if at least one of its enablers is enabled,
1857          * we enable the event_notifier, else we disable it.
1858          */
1859         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1860                 struct lttng_enabler_ref *enabler_ref;
1861                 struct lttng_bytecode_runtime *runtime;
1862                 int enabled = 0, has_enablers_without_bytecode = 0;
1863
1864                 /* Enable event_notifiers */
1865                 cds_list_for_each_entry(enabler_ref,
1866                                 &event_notifier->enablers_ref_head, node) {
1867                         if (enabler_ref->ref->enabled) {
1868                                 enabled = 1;
1869                                 break;
1870                         }
1871                 }
1872
1873                 CMM_STORE_SHARED(event_notifier->enabled, enabled);
1874                 /*
1875                  * Sync tracepoint registration with event_notifier enabled
1876                  * state.
1877                  */
1878                 if (enabled) {
1879                         if (!event_notifier->registered)
1880                                 register_event_notifier(event_notifier);
1881                 } else {
1882                         if (event_notifier->registered)
1883                                 unregister_event_notifier(event_notifier);
1884                 }
1885
1886                 /* Check if has enablers without bytecode enabled */
1887                 cds_list_for_each_entry(enabler_ref,
1888                                 &event_notifier->enablers_ref_head, node) {
1889                         if (enabler_ref->ref->enabled
1890                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1891                                 has_enablers_without_bytecode = 1;
1892                                 break;
1893                         }
1894                 }
1895                 event_notifier->has_enablers_without_bytecode =
1896                         has_enablers_without_bytecode;
1897
1898                 /* Enable filters */
1899                 cds_list_for_each_entry(runtime,
1900                                 &event_notifier->filter_bytecode_runtime_head, node) {
1901                         lttng_bytecode_filter_sync_state(runtime);
1902                 }
1903
1904                 /* Enable captures. */
1905                 cds_list_for_each_entry(runtime,
1906                                 &event_notifier->capture_bytecode_runtime_head, node) {
1907                         lttng_bytecode_capture_sync_state(runtime);
1908                 }
1909         }
1910         __tracepoint_probe_prune_release_queue();
1911 }
1912
1913 /*
1914  * Apply enablers to session events, adding events to session if need
1915  * be. It is required after each modification applied to an active
1916  * session, and right before session "start".
1917  * "lazy" sync means we only sync if required.
1918  */
1919 static
1920 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1921 {
1922         /* We can skip if session is not active */
1923         if (!session->active)
1924                 return;
1925         lttng_session_sync_event_enablers(session);
1926 }
1927
1928 /*
1929  * Update all sessions with the given app context.
1930  * Called with ust lock held.
1931  * This is invoked when an application context gets loaded/unloaded. It
1932  * ensures the context callbacks are in sync with the application
1933  * context (either app context callbacks, or dummy callbacks).
1934  */
1935 void lttng_ust_context_set_session_provider(const char *name,
1936                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1937                 void (*record)(struct lttng_ctx_field *field,
1938                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1939                         struct lttng_channel *chan),
1940                 void (*get_value)(struct lttng_ctx_field *field,
1941                         struct lttng_ctx_value *value))
1942 {
1943         struct lttng_session *session;
1944
1945         cds_list_for_each_entry(session, &sessions, node) {
1946                 struct lttng_channel *chan;
1947                 struct lttng_event *event;
1948                 int ret;
1949
1950                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1951                                 name, get_size, record, get_value);
1952                 if (ret)
1953                         abort();
1954                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1955                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1956                                         name, get_size, record, get_value);
1957                         if (ret)
1958                                 abort();
1959                 }
1960                 cds_list_for_each_entry(event, &session->events_head, node) {
1961                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1962                                         name, get_size, record, get_value);
1963                         if (ret)
1964                                 abort();
1965                 }
1966         }
1967 }
1968
1969 /*
1970  * Update all event_notifier groups with the given app context.
1971  * Called with ust lock held.
1972  * This is invoked when an application context gets loaded/unloaded. It
1973  * ensures the context callbacks are in sync with the application
1974  * context (either app context callbacks, or dummy callbacks).
1975  */
1976 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
1977                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1978                 void (*record)(struct lttng_ctx_field *field,
1979                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1980                         struct lttng_channel *chan),
1981                 void (*get_value)(struct lttng_ctx_field *field,
1982                         struct lttng_ctx_value *value))
1983 {
1984         struct lttng_event_notifier_group *event_notifier_group;
1985
1986         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1987                 int ret;
1988
1989                 ret = lttng_ust_context_set_provider_rcu(
1990                                 &event_notifier_group->ctx,
1991                                 name, get_size, record, get_value);
1992                 if (ret)
1993                         abort();
1994         }
1995 }