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 <dlfcn.h>
  38 #include <lttng/ust-endian.h>
  39
  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 struct lttng_session *lttng_session_create(void)
 147 {
 148         struct lttng_session *session;
 149         int i;
 150
 151         session = zmalloc(sizeof(struct lttng_session));
 152         if (!session)
 153                 return NULL;
 154         if (lttng_context_init_all(&session->ctx)) {
 155                 free(session);
 156                 return NULL;
 157         }
 158         CDS_INIT_LIST_HEAD(&session->chan_head);
 159         CDS_INIT_LIST_HEAD(&session->events_head);
 160         CDS_INIT_LIST_HEAD(&session->enums_head);
 161         CDS_INIT_LIST_HEAD(&session->enablers_head);
 162         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 163                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 164         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 165                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 166         cds_list_add(&session->node, &sessions);
 167         return session;
 168 }
 169
 170 struct lttng_counter *lttng_ust_counter_create(
 171                 const char *counter_transport_name,
 172                 size_t number_dimensions, const struct lttng_counter_dimension *dimensions)
 173 {
 174         struct lttng_counter_transport *counter_transport = NULL;
 175         struct lttng_counter *counter = NULL;
 176
 177         counter_transport = lttng_counter_transport_find(counter_transport_name);
 178         if (!counter_transport)
 179                 goto notransport;
 180         counter = zmalloc(sizeof(struct lttng_counter));
 181         if (!counter)
 182                 goto nomem;
 183
 184         counter->ops = &counter_transport->ops;
 185         counter->transport = counter_transport;
 186
 187         counter->counter = counter->ops->counter_create(
 188                         number_dimensions, dimensions, 0,
 189                         -1, 0, NULL, false);
 190         if (!counter->counter) {
 191                 goto create_error;
 192         }
 193
 194         return counter;
 195
 196 create_error:
 197         free(counter);
 198 nomem:
 199 notransport:
 200         return NULL;
 201 }
 202
 203 static
 204 void lttng_ust_counter_destroy(struct lttng_counter *counter)
 205 {
 206         counter->ops->counter_destroy(counter->counter);
 207         free(counter);
 208 }
 209
 210 struct lttng_event_notifier_group *lttng_event_notifier_group_create(void)
 211 {
 212         struct lttng_event_notifier_group *event_notifier_group;
 213         int i;
 214
 215         event_notifier_group = zmalloc(sizeof(struct lttng_event_notifier_group));
 216         if (!event_notifier_group)
 217                 return NULL;
 218
 219         /* Add all contexts. */
 220         if (lttng_context_init_all(&event_notifier_group->ctx)) {
 221                 free(event_notifier_group);
 222                 return NULL;
 223         }
 224
 225         CDS_INIT_LIST_HEAD(&event_notifier_group->enablers_head);
 226         CDS_INIT_LIST_HEAD(&event_notifier_group->event_notifiers_head);
 227         for (i = 0; i < LTTNG_UST_EVENT_NOTIFIER_HT_SIZE; i++)
 228                 CDS_INIT_HLIST_HEAD(&event_notifier_group->event_notifiers_ht.table[i]);
 229
 230         cds_list_add(&event_notifier_group->node, &event_notifier_groups);
 231
 232         return event_notifier_group;
 233 }
 234
 235 /*
 236  * Only used internally at session destruction.
 237  */
 238 static
 239 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 240 {
 241         struct channel *chan;
 242         struct lttng_ust_shm_handle *handle;
 243
 244         cds_list_del(&lttng_chan->node);
 245         lttng_destroy_context(lttng_chan->ctx);
 246         chan = lttng_chan->chan;
 247         handle = lttng_chan->handle;
 248         /*
 249          * note: lttng_chan is private data contained within handle. It
 250          * will be freed along with the handle.
 251          */
 252         channel_destroy(chan, handle, 0);
 253 }
 254
 255 static
 256 void register_event(struct lttng_event *event)
 257 {
 258         int ret;
 259         const struct lttng_event_desc *desc;
 260
 261         assert(event->registered == 0);
 262         desc = event->desc;
 263         ret = __tracepoint_probe_register_queue_release(desc->name,
 264                         desc->probe_callback,
 265                         event, desc->signature);
 266         WARN_ON_ONCE(ret);
 267         if (!ret)
 268                 event->registered = 1;
 269 }
 270
 271 static
 272 void register_event_notifier(struct lttng_event_notifier *event_notifier)
 273 {
 274         int ret;
 275         const struct lttng_event_desc *desc;
 276
 277         assert(event_notifier->registered == 0);
 278         desc = event_notifier->desc;
 279         ret = __tracepoint_probe_register_queue_release(desc->name,
 280                 desc->u.ext.event_notifier_callback, event_notifier, desc->signature);
 281         WARN_ON_ONCE(ret);
 282         if (!ret)
 283                 event_notifier->registered = 1;
 284 }
 285
 286 static
 287 void unregister_event(struct lttng_event *event)
 288 {
 289         int ret;
 290         const struct lttng_event_desc *desc;
 291
 292         assert(event->registered == 1);
 293         desc = event->desc;
 294         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 295                         desc->probe_callback,
 296                         event);
 297         WARN_ON_ONCE(ret);
 298         if (!ret)
 299                 event->registered = 0;
 300 }
 301
 302 static
 303 void unregister_event_notifier(struct lttng_event_notifier *event_notifier)
 304 {
 305         int ret;
 306         const struct lttng_event_desc *desc;
 307
 308         assert(event_notifier->registered == 1);
 309         desc = event_notifier->desc;
 310         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 311                 desc->u.ext.event_notifier_callback, event_notifier);
 312         WARN_ON_ONCE(ret);
 313         if (!ret)
 314                 event_notifier->registered = 0;
 315 }
 316
 317 /*
 318  * Only used internally at session destruction.
 319  */
 320 static
 321 void _lttng_event_unregister(struct lttng_event *event)
 322 {
 323         if (event->registered)
 324                 unregister_event(event);
 325 }
 326
 327 /*
 328  * Only used internally at session destruction.
 329  */
 330 static
 331 void _lttng_event_notifier_unregister(struct lttng_event_notifier *event_notifier)
 332 {
 333         if (event_notifier->registered)
 334                 unregister_event_notifier(event_notifier);
 335 }
 336
 337 void lttng_session_destroy(struct lttng_session *session)
 338 {
 339         struct lttng_channel *chan, *tmpchan;
 340         struct lttng_event *event, *tmpevent;
 341         struct lttng_enum *_enum, *tmp_enum;
 342         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 343
 344         CMM_ACCESS_ONCE(session->active) = 0;
 345         cds_list_for_each_entry(event, &session->events_head, node) {
 346                 _lttng_event_unregister(event);
 347         }
 348         lttng_ust_synchronize_trace();  /* Wait for in-flight events to complete */
 349         __tracepoint_probe_prune_release_queue();
 350         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 351                         &session->enablers_head, node)
 352                 lttng_event_enabler_destroy(event_enabler);
 353         cds_list_for_each_entry_safe(event, tmpevent,
 354                         &session->events_head, node)
 355                 _lttng_event_destroy(event);
 356         cds_list_for_each_entry_safe(_enum, tmp_enum,
 357                         &session->enums_head, node)
 358                 _lttng_enum_destroy(_enum);
 359         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 360                 _lttng_channel_unmap(chan);
 361         cds_list_del(&session->node);
 362         lttng_destroy_context(session->ctx);
 363         free(session);
 364 }
 365
 366 void lttng_event_notifier_group_destroy(
 367                 struct lttng_event_notifier_group *event_notifier_group)
 368 {
 369         int close_ret;
 370         struct lttng_event_notifier_enabler *notifier_enabler, *tmpnotifier_enabler;
 371         struct lttng_event_notifier *notifier, *tmpnotifier;
 372
 373         if (!event_notifier_group) {
 374                 return;
 375         }
 376
 377         cds_list_for_each_entry(notifier,
 378                         &event_notifier_group->event_notifiers_head, node)
 379                 _lttng_event_notifier_unregister(notifier);
 380
 381         lttng_ust_synchronize_trace();
 382
 383         cds_list_for_each_entry_safe(notifier_enabler, tmpnotifier_enabler,
 384                         &event_notifier_group->enablers_head, node)
 385                 lttng_event_notifier_enabler_destroy(notifier_enabler);
 386
 387         cds_list_for_each_entry_safe(notifier, tmpnotifier,
 388                         &event_notifier_group->event_notifiers_head, node)
 389                 _lttng_event_notifier_destroy(notifier);
 390
 391         if (event_notifier_group->error_counter)
 392                 lttng_ust_counter_destroy(event_notifier_group->error_counter);
 393
 394         /* Close the notification fd to the listener of event_notifiers. */
 395
 396         lttng_ust_lock_fd_tracker();
 397         close_ret = close(event_notifier_group->notification_fd);
 398         if (!close_ret) {
 399                 lttng_ust_delete_fd_from_tracker(
 400                                 event_notifier_group->notification_fd);
 401         } else {
 402                 PERROR("close");
 403                 abort();
 404         }
 405         lttng_ust_unlock_fd_tracker();
 406
 407         cds_list_del(&event_notifier_group->node);
 408
 409         free(event_notifier_group);
 410 }
 411
 412 static
 413 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 414 {
 415         struct lttng_ust_bytecode_node *filter_node, *tmp_filter_node;
 416         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 417
 418         if (!enabler) {
 419                 return;
 420         }
 421
 422         /* Destroy filter bytecode */
 423         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 424                         &enabler->filter_bytecode_head, node) {
 425                 free(filter_node);
 426         }
 427
 428         /* Destroy excluders */
 429         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 430                         &enabler->excluder_head, node) {
 431                 free(excluder_node);
 432         }
 433 }
 434
 435  void lttng_event_notifier_enabler_destroy(struct lttng_event_notifier_enabler *event_notifier_enabler)
 436 {
 437         if (!event_notifier_enabler) {
 438                 return;
 439         }
 440
 441         cds_list_del(&event_notifier_enabler->node);
 442
 443         lttng_enabler_destroy(lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
 444
 445         free(event_notifier_enabler);
 446 }
 447
 448 static
 449 int lttng_enum_create(const struct lttng_enum_desc *desc,
 450                 struct lttng_session *session)
 451 {
 452         const char *enum_name = desc->name;
 453         struct lttng_enum *_enum;
 454         struct cds_hlist_head *head;
 455         int ret = 0;
 456         size_t name_len = strlen(enum_name);
 457         uint32_t hash;
 458         int notify_socket;
 459
 460         /* Check if this enum is already registered for this session. */
 461         hash = jhash(enum_name, name_len, 0);
 462         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 463
 464         _enum = lttng_ust_enum_get_from_desc(session, desc);
 465         if (_enum) {
 466                 ret = -EEXIST;
 467                 goto exist;
 468         }
 469
 470         notify_socket = lttng_get_notify_socket(session->owner);
 471         if (notify_socket < 0) {
 472                 ret = notify_socket;
 473                 goto socket_error;
 474         }
 475
 476         _enum = zmalloc(sizeof(*_enum));
 477         if (!_enum) {
 478                 ret = -ENOMEM;
 479                 goto cache_error;
 480         }
 481         _enum->session = session;
 482         _enum->desc = desc;
 483
 484         ret = ustcomm_register_enum(notify_socket,
 485                 session->objd,
 486                 enum_name,
 487                 desc->nr_entries,
 488                 desc->entries,
 489                 &_enum->id);
 490         if (ret < 0) {
 491                 DBG("Error (%d) registering enumeration to sessiond", ret);
 492                 goto sessiond_register_error;
 493         }
 494         cds_list_add(&_enum->node, &session->enums_head);
 495         cds_hlist_add_head(&_enum->hlist, head);
 496         return 0;
 497
 498 sessiond_register_error:
 499         free(_enum);
 500 cache_error:
 501 socket_error:
 502 exist:
 503         return ret;
 504 }
 505
 506 static
 507 int lttng_create_enum_check(const struct lttng_type *type,
 508                 struct lttng_session *session)
 509 {
 510         switch (type->atype) {
 511         case atype_enum:
 512         {
 513                 const struct lttng_enum_desc *enum_desc;
 514                 int ret;
 515
 516                 enum_desc = type->u.legacy.basic.enumeration.desc;
 517                 ret = lttng_enum_create(enum_desc, session);
 518                 if (ret && ret != -EEXIST) {
 519                         DBG("Unable to create enum error: (%d)", ret);
 520                         return ret;
 521                 }
 522                 break;
 523         }
 524         case atype_enum_nestable:
 525         {
 526                 const struct lttng_enum_desc *enum_desc;
 527                 int ret;
 528
 529                 enum_desc = type->u.enum_nestable.desc;
 530                 ret = lttng_enum_create(enum_desc, session);
 531                 if (ret && ret != -EEXIST) {
 532                         DBG("Unable to create enum error: (%d)", ret);
 533                         return ret;
 534                 }
 535                 break;
 536         }
 537         case atype_dynamic:
 538         {
 539                 const struct lttng_event_field *tag_field_generic;
 540                 const struct lttng_enum_desc *enum_desc;
 541                 int ret;
 542
 543                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 544                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 545                 ret = lttng_enum_create(enum_desc, session);
 546                 if (ret && ret != -EEXIST) {
 547                         DBG("Unable to create enum error: (%d)", ret);
 548                         return ret;
 549                 }
 550                 break;
 551         }
 552         default:
 553                 /* TODO: nested types when they become supported. */
 554                 break;
 555         }
 556         return 0;
 557 }
 558
 559 static
 560 int lttng_create_all_event_enums(size_t nr_fields,
 561                 const struct lttng_event_field *event_fields,
 562                 struct lttng_session *session)
 563 {
 564         size_t i;
 565         int ret;
 566
 567         /* For each field, ensure enum is part of the session. */
 568         for (i = 0; i < nr_fields; i++) {
 569                 const struct lttng_type *type = &event_fields[i].type;
 570
 571                 ret = lttng_create_enum_check(type, session);
 572                 if (ret)
 573                         return ret;
 574         }
 575         return 0;
 576 }
 577
 578 static
 579 int lttng_create_all_ctx_enums(size_t nr_fields,
 580                 const struct lttng_ctx_field *ctx_fields,
 581                 struct lttng_session *session)
 582 {
 583         size_t i;
 584         int ret;
 585
 586         /* For each field, ensure enum is part of the session. */
 587         for (i = 0; i < nr_fields; i++) {
 588                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 589
 590                 ret = lttng_create_enum_check(type, session);
 591                 if (ret)
 592                         return ret;
 593         }
 594         return 0;
 595 }
 596
 597 /*
 598  * Ensure that a state-dump will be performed for this session at the end
 599  * of the current handle_message().
 600  */
 601 int lttng_session_statedump(struct lttng_session *session)
 602 {
 603         session->statedump_pending = 1;
 604         lttng_ust_sockinfo_session_enabled(session->owner);
 605         return 0;
 606 }
 607
 608 int lttng_session_enable(struct lttng_session *session)
 609 {
 610         int ret = 0;
 611         struct lttng_channel *chan;
 612         int notify_socket;
 613
 614         if (session->active) {
 615                 ret = -EBUSY;
 616                 goto end;
 617         }
 618
 619         notify_socket = lttng_get_notify_socket(session->owner);
 620         if (notify_socket < 0)
 621                 return notify_socket;
 622
 623         /* Set transient enabler state to "enabled" */
 624         session->tstate = 1;
 625
 626         /* We need to sync enablers with session before activation. */
 627         lttng_session_sync_event_enablers(session);
 628
 629         /*
 630          * Snapshot the number of events per channel to know the type of header
 631          * we need to use.
 632          */
 633         cds_list_for_each_entry(chan, &session->chan_head, node) {
 634                 const struct lttng_ctx *ctx;
 635                 const struct lttng_ctx_field *fields = NULL;
 636                 size_t nr_fields = 0;
 637                 uint32_t chan_id;
 638
 639                 /* don't change it if session stop/restart */
 640                 if (chan->header_type)
 641                         continue;
 642                 ctx = chan->ctx;
 643                 if (ctx) {
 644                         nr_fields = ctx->nr_fields;
 645                         fields = ctx->fields;
 646                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 647                                 session);
 648                         if (ret < 0) {
 649                                 DBG("Error (%d) adding enum to session", ret);
 650                                 return ret;
 651                         }
 652                 }
 653                 ret = ustcomm_register_channel(notify_socket,
 654                         session,
 655                         session->objd,
 656                         chan->objd,
 657                         nr_fields,
 658                         fields,
 659                         &chan_id,
 660                         &chan->header_type);
 661                 if (ret) {
 662                         DBG("Error (%d) registering channel to sessiond", ret);
 663                         return ret;
 664                 }
 665                 if (chan_id != chan->id) {
 666                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 667                                 chan_id, chan->id);
 668                         return -EINVAL;
 669                 }
 670         }
 671
 672         /* Set atomically the state to "active" */
 673         CMM_ACCESS_ONCE(session->active) = 1;
 674         CMM_ACCESS_ONCE(session->been_active) = 1;
 675
 676         ret = lttng_session_statedump(session);
 677         if (ret)
 678                 return ret;
 679 end:
 680         return ret;
 681 }
 682
 683 int lttng_session_disable(struct lttng_session *session)
 684 {
 685         int ret = 0;
 686
 687         if (!session->active) {
 688                 ret = -EBUSY;
 689                 goto end;
 690         }
 691         /* Set atomically the state to "inactive" */
 692         CMM_ACCESS_ONCE(session->active) = 0;
 693
 694         /* Set transient enabler state to "disabled" */
 695         session->tstate = 0;
 696         lttng_session_sync_event_enablers(session);
 697 end:
 698         return ret;
 699 }
 700
 701 int lttng_channel_enable(struct lttng_channel *channel)
 702 {
 703         int ret = 0;
 704
 705         if (channel->enabled) {
 706                 ret = -EBUSY;
 707                 goto end;
 708         }
 709         /* Set transient enabler state to "enabled" */
 710         channel->tstate = 1;
 711         lttng_session_sync_event_enablers(channel->session);
 712         /* Set atomically the state to "enabled" */
 713         CMM_ACCESS_ONCE(channel->enabled) = 1;
 714 end:
 715         return ret;
 716 }
 717
 718 int lttng_channel_disable(struct lttng_channel *channel)
 719 {
 720         int ret = 0;
 721
 722         if (!channel->enabled) {
 723                 ret = -EBUSY;
 724                 goto end;
 725         }
 726         /* Set atomically the state to "disabled" */
 727         CMM_ACCESS_ONCE(channel->enabled) = 0;
 728         /* Set transient enabler state to "enabled" */
 729         channel->tstate = 0;
 730         lttng_session_sync_event_enablers(channel->session);
 731 end:
 732         return ret;
 733 }
 734
 735 static inline
 736 struct cds_hlist_head *borrow_hash_table_bucket(
 737                 struct cds_hlist_head *hash_table,
 738                 unsigned int hash_table_size,
 739                 const struct lttng_event_desc *desc)
 740 {
 741         const char *event_name;
 742         size_t name_len;
 743         uint32_t hash;
 744
 745         event_name = desc->name;
 746         name_len = strlen(event_name);
 747
 748         hash = jhash(event_name, name_len, 0);
 749         return &hash_table[hash & (hash_table_size - 1)];
 750 }
 751
 752 /*
 753  * Supports event creation while tracing session is active.
 754  */
 755 static
 756 int lttng_event_create(const struct lttng_event_desc *desc,
 757                 struct lttng_channel *chan)
 758 {
 759         struct lttng_event *event;
 760         struct lttng_session *session = chan->session;
 761         struct cds_hlist_head *head;
 762         int ret = 0;
 763         int notify_socket, loglevel;
 764         const char *uri;
 765
 766         head = borrow_hash_table_bucket(chan->session->events_ht.table,
 767                 LTTNG_UST_EVENT_HT_SIZE, desc);
 768
 769         notify_socket = lttng_get_notify_socket(session->owner);
 770         if (notify_socket < 0) {
 771                 ret = notify_socket;
 772                 goto socket_error;
 773         }
 774
 775         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 776                         session);
 777         if (ret < 0) {
 778                 DBG("Error (%d) adding enum to session", ret);
 779                 goto create_enum_error;
 780         }
 781
 782         /*
 783          * Check if loglevel match. Refuse to connect event if not.
 784          */
 785         event = zmalloc(sizeof(struct lttng_event));
 786         if (!event) {
 787                 ret = -ENOMEM;
 788                 goto cache_error;
 789         }
 790         event->chan = chan;
 791
 792         /* Event will be enabled by enabler sync. */
 793         event->enabled = 0;
 794         event->registered = 0;
 795         CDS_INIT_LIST_HEAD(&event->filter_bytecode_runtime_head);
 796         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 797         event->desc = desc;
 798
 799         if (desc->loglevel)
 800                 loglevel = *(*event->desc->loglevel);
 801         else
 802                 loglevel = TRACE_DEFAULT;
 803         if (desc->u.ext.model_emf_uri)
 804                 uri = *(desc->u.ext.model_emf_uri);
 805         else
 806                 uri = NULL;
 807
 808         /* Fetch event ID from sessiond */
 809         ret = ustcomm_register_event(notify_socket,
 810                 session,
 811                 session->objd,
 812                 chan->objd,
 813                 desc->name,
 814                 loglevel,
 815                 desc->signature,
 816                 desc->nr_fields,
 817                 desc->fields,
 818                 uri,
 819                 &event->id);
 820         if (ret < 0) {
 821                 DBG("Error (%d) registering event to sessiond", ret);
 822                 goto sessiond_register_error;
 823         }
 824
 825         cds_list_add(&event->node, &chan->session->events_head);
 826         cds_hlist_add_head(&event->hlist, head);
 827         return 0;
 828
 829 sessiond_register_error:
 830         free(event);
 831 cache_error:
 832 create_enum_error:
 833 socket_error:
 834         return ret;
 835 }
 836
 837 static
 838 int lttng_event_notifier_create(const struct lttng_event_desc *desc,
 839                 uint64_t token, uint64_t error_counter_index,
 840                 struct lttng_event_notifier_group *event_notifier_group)
 841 {
 842         struct lttng_event_notifier *event_notifier;
 843         struct cds_hlist_head *head;
 844         int ret = 0;
 845
 846         /*
 847          * Get the hashtable bucket the created lttng_event_notifier object
 848          * should be inserted.
 849          */
 850         head = borrow_hash_table_bucket(
 851                 event_notifier_group->event_notifiers_ht.table,
 852                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
 853
 854         event_notifier = zmalloc(sizeof(struct lttng_event_notifier));
 855         if (!event_notifier) {
 856                 ret = -ENOMEM;
 857                 goto error;
 858         }
 859
 860         event_notifier->group = event_notifier_group;
 861         event_notifier->user_token = token;
 862         event_notifier->error_counter_index = error_counter_index;
 863
 864         /* Event notifier will be enabled by enabler sync. */
 865         event_notifier->enabled = 0;
 866         event_notifier->registered = 0;
 867
 868         CDS_INIT_LIST_HEAD(&event_notifier->filter_bytecode_runtime_head);
 869         CDS_INIT_LIST_HEAD(&event_notifier->capture_bytecode_runtime_head);
 870         CDS_INIT_LIST_HEAD(&event_notifier->enablers_ref_head);
 871         event_notifier->desc = desc;
 872
 873         cds_list_add(&event_notifier->node,
 874                         &event_notifier_group->event_notifiers_head);
 875         cds_hlist_add_head(&event_notifier->hlist, head);
 876
 877         return 0;
 878
 879 error:
 880         return ret;
 881 }
 882
 883 static
 884 void _lttng_event_notifier_destroy(struct lttng_event_notifier *event_notifier)
 885 {
 886         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 887
 888         /* Remove from event_notifier list. */
 889         cds_list_del(&event_notifier->node);
 890         /* Remove from event_notifier hash table. */
 891         cds_hlist_del(&event_notifier->hlist);
 892
 893         lttng_free_event_notifier_filter_runtime(event_notifier);
 894
 895         /* Free event_notifier enabler refs */
 896         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 897                         &event_notifier->enablers_ref_head, node)
 898                 free(enabler_ref);
 899         free(event_notifier);
 900 }
 901
 902 static
 903 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 904                 struct lttng_enabler *enabler)
 905 {
 906         int loglevel = 0;
 907         unsigned int has_loglevel = 0;
 908
 909         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 910         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 911                         desc->name, SIZE_MAX))
 912                 return 0;
 913         if (desc->loglevel) {
 914                 loglevel = *(*desc->loglevel);
 915                 has_loglevel = 1;
 916         }
 917         if (!lttng_loglevel_match(loglevel,
 918                         has_loglevel,
 919                         enabler->event_param.loglevel_type,
 920                         enabler->event_param.loglevel))
 921                 return 0;
 922         return 1;
 923 }
 924
 925 static
 926 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 927                 struct lttng_enabler *enabler)
 928 {
 929         int loglevel = 0;
 930         unsigned int has_loglevel = 0;
 931
 932         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 933         if (strcmp(desc->name, enabler->event_param.name))
 934                 return 0;
 935         if (desc->loglevel) {
 936                 loglevel = *(*desc->loglevel);
 937                 has_loglevel = 1;
 938         }
 939         if (!lttng_loglevel_match(loglevel,
 940                         has_loglevel,
 941                         enabler->event_param.loglevel_type,
 942                         enabler->event_param.loglevel))
 943                 return 0;
 944         return 1;
 945 }
 946
 947 static
 948 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 949                 struct lttng_enabler *enabler)
 950 {
 951         switch (enabler->format_type) {
 952         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 953         {
 954                 struct lttng_ust_excluder_node *excluder;
 955
 956                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 957                         return 0;
 958                 }
 959
 960                 /*
 961                  * If the matching event matches with an excluder,
 962                  * return 'does not match'
 963                  */
 964                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 965                         int count;
 966
 967                         for (count = 0; count < excluder->excluder.count; count++) {
 968                                 int len;
 969                                 char *excluder_name;
 970
 971                                 excluder_name = (char *) (excluder->excluder.names)
 972                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 973                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 974                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 975                                         return 0;
 976                         }
 977                 }
 978                 return 1;
 979         }
 980         case LTTNG_ENABLER_FORMAT_EVENT:
 981                 return lttng_desc_match_event_enabler(desc, enabler);
 982         default:
 983                 return -EINVAL;
 984         }
 985 }
 986
 987 static
 988 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 989                 struct lttng_event *event)
 990 {
 991         if (lttng_desc_match_enabler(event->desc,
 992                         lttng_event_enabler_as_enabler(event_enabler))
 993                         && event->chan == event_enabler->chan)
 994                 return 1;
 995         else
 996                 return 0;
 997 }
 998
 999 static
1000 int lttng_event_notifier_enabler_match_event_notifier(
1001                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1002                 struct lttng_event_notifier *event_notifier)
1003 {
1004         int desc_matches = lttng_desc_match_enabler(event_notifier->desc,
1005                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1006
1007         if (desc_matches && event_notifier->group == event_notifier_enabler->group &&
1008                         event_notifier->user_token == event_notifier_enabler->user_token)
1009                 return 1;
1010         else
1011                 return 0;
1012 }
1013
1014 static
1015 struct lttng_enabler_ref *lttng_enabler_ref(
1016                 struct cds_list_head *enabler_ref_list,
1017                 struct lttng_enabler *enabler)
1018 {
1019         struct lttng_enabler_ref *enabler_ref;
1020
1021         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
1022                 if (enabler_ref->ref == enabler)
1023                         return enabler_ref;
1024         }
1025         return NULL;
1026 }
1027
1028 /*
1029  * Create struct lttng_event if it is missing and present in the list of
1030  * tracepoint probes.
1031  */
1032 static
1033 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
1034 {
1035         struct lttng_session *session = event_enabler->chan->session;
1036         struct lttng_probe_desc *probe_desc;
1037         const struct lttng_event_desc *desc;
1038         struct lttng_event *event;
1039         int i;
1040         struct cds_list_head *probe_list;
1041
1042         probe_list = lttng_get_probe_list_head();
1043         /*
1044          * For each probe event, if we find that a probe event matches
1045          * our enabler, create an associated lttng_event if not
1046          * already present.
1047          */
1048         cds_list_for_each_entry(probe_desc, probe_list, head) {
1049                 for (i = 0; i < probe_desc->nr_events; i++) {
1050                         int ret;
1051                         bool found = false;
1052                         struct cds_hlist_head *head;
1053                         struct cds_hlist_node *node;
1054
1055                         desc = probe_desc->event_desc[i];
1056                         if (!lttng_desc_match_enabler(desc,
1057                                         lttng_event_enabler_as_enabler(event_enabler)))
1058                                 continue;
1059
1060                         head = borrow_hash_table_bucket(
1061                                 session->events_ht.table,
1062                                 LTTNG_UST_EVENT_HT_SIZE, desc);
1063
1064                         cds_hlist_for_each_entry(event, node, head, hlist) {
1065                                 if (event->desc == desc
1066                                                 && event->chan == event_enabler->chan) {
1067                                         found = true;
1068                                         break;
1069                                 }
1070                         }
1071                         if (found)
1072                                 continue;
1073
1074                         /*
1075                          * We need to create an event for this
1076                          * event probe.
1077                          */
1078                         ret = lttng_event_create(probe_desc->event_desc[i],
1079                                         event_enabler->chan);
1080                         if (ret) {
1081                                 DBG("Unable to create event %s, error %d\n",
1082                                         probe_desc->event_desc[i]->name, ret);
1083                         }
1084                 }
1085         }
1086 }
1087
1088 static
1089 void probe_provider_event_for_each(struct lttng_probe_desc *provider_desc,
1090                 void (*event_func)(struct lttng_session *session,
1091                         struct lttng_event *event),
1092                 void (*event_notifier_func)(struct lttng_event_notifier *event_notifier))
1093 {
1094         struct cds_hlist_node *node, *tmp_node;
1095         struct cds_list_head *sessionsp;
1096         unsigned int i;
1097
1098         /* Get handle on list of sessions. */
1099         sessionsp = _lttng_get_sessions();
1100
1101         /*
1102          * Iterate over all events in the probe provider descriptions and
1103          * sessions to queue the unregistration of the events.
1104          */
1105         for (i = 0; i < provider_desc->nr_events; i++) {
1106                 const struct lttng_event_desc *event_desc;
1107                 struct lttng_event_notifier_group *event_notifier_group;
1108                 struct lttng_event_notifier *event_notifier;
1109                 struct lttng_session *session;
1110                 struct cds_hlist_head *head;
1111                 struct lttng_event *event;
1112
1113                 event_desc = provider_desc->event_desc[i];
1114
1115                 /*
1116                  * Iterate over all session to find the current event
1117                  * description.
1118                  */
1119                 cds_list_for_each_entry(session, sessionsp, node) {
1120                         /*
1121                          * Get the list of events in the hashtable bucket and
1122                          * iterate to find the event matching this descriptor.
1123                          */
1124                         head = borrow_hash_table_bucket(
1125                                 session->events_ht.table,
1126                                 LTTNG_UST_EVENT_HT_SIZE, event_desc);
1127
1128                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
1129                                 if (event_desc == event->desc) {
1130                                         event_func(session, event);
1131                                         break;
1132                                 }
1133                         }
1134                 }
1135
1136                 /*
1137                  * Iterate over all event_notifier groups to find the current event
1138                  * description.
1139                  */
1140                 cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1141                         /*
1142                          * Get the list of event_notifiers in the hashtable bucket and
1143                          * iterate to find the event_notifier matching this
1144                          * descriptor.
1145                          */
1146                         head = borrow_hash_table_bucket(
1147                                 event_notifier_group->event_notifiers_ht.table,
1148                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, event_desc);
1149
1150                         cds_hlist_for_each_entry_safe(event_notifier, node, tmp_node, head, hlist) {
1151                                 if (event_desc == event_notifier->desc) {
1152                                         event_notifier_func(event_notifier);
1153                                         break;
1154                                 }
1155                         }
1156                 }
1157         }
1158 }
1159
1160 static
1161 void _unregister_event(struct lttng_session *session,
1162                 struct lttng_event *event)
1163 {
1164         _lttng_event_unregister(event);
1165 }
1166
1167 static
1168 void _event_enum_destroy(struct lttng_session *session,
1169                 struct lttng_event *event)
1170 {
1171         unsigned int i;
1172
1173         /* Destroy enums of the current event. */
1174         for (i = 0; i < event->desc->nr_fields; i++) {
1175                 const struct lttng_enum_desc *enum_desc;
1176                 const struct lttng_event_field *field;
1177                 struct lttng_enum *curr_enum;
1178
1179                 field = &(event->desc->fields[i]);
1180                 switch (field->type.atype) {
1181                 case atype_enum:
1182                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
1183                         break;
1184                 case atype_enum_nestable:
1185                         enum_desc = field->type.u.enum_nestable.desc;
1186                         break;
1187                 default:
1188                         continue;
1189                 }
1190
1191                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
1192                 if (curr_enum) {
1193                         _lttng_enum_destroy(curr_enum);
1194                 }
1195         }
1196
1197         /* Destroy event. */
1198         _lttng_event_destroy(event);
1199 }
1200
1201 /*
1202  * Iterate over all the UST sessions to unregister and destroy all probes from
1203  * the probe provider descriptor received as argument. Must me called with the
1204  * ust_lock held.
1205  */
1206 void lttng_probe_provider_unregister_events(
1207                 struct lttng_probe_desc *provider_desc)
1208 {
1209         /*
1210          * Iterate over all events in the probe provider descriptions and sessions
1211          * to queue the unregistration of the events.
1212          */
1213         probe_provider_event_for_each(provider_desc, _unregister_event,
1214                 _lttng_event_notifier_unregister);
1215
1216         /* Wait for grace period. */
1217         lttng_ust_synchronize_trace();
1218         /* Prune the unregistration queue. */
1219         __tracepoint_probe_prune_release_queue();
1220
1221         /*
1222          * It is now safe to destroy the events and remove them from the event list
1223          * and hashtables.
1224          */
1225         probe_provider_event_for_each(provider_desc, _event_enum_destroy,
1226                 _lttng_event_notifier_destroy);
1227 }
1228
1229 /*
1230  * Create events associated with an event enabler (if not already present),
1231  * and add backward reference from the event to the enabler.
1232  */
1233 static
1234 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
1235 {
1236         struct lttng_session *session = event_enabler->chan->session;
1237         struct lttng_event *event;
1238
1239         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
1240                 goto end;
1241
1242         /* First ensure that probe events are created for this enabler. */
1243         lttng_create_event_if_missing(event_enabler);
1244
1245         /* For each event matching enabler in session event list. */
1246         cds_list_for_each_entry(event, &session->events_head, node) {
1247                 struct lttng_enabler_ref *enabler_ref;
1248
1249                 if (!lttng_event_enabler_match_event(event_enabler, event))
1250                         continue;
1251
1252                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
1253                         lttng_event_enabler_as_enabler(event_enabler));
1254                 if (!enabler_ref) {
1255                         /*
1256                          * If no backward ref, create it.
1257                          * Add backward ref from event to enabler.
1258                          */
1259                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1260                         if (!enabler_ref)
1261                                 return -ENOMEM;
1262                         enabler_ref->ref = lttng_event_enabler_as_enabler(
1263                                 event_enabler);
1264                         cds_list_add(&enabler_ref->node,
1265                                 &event->enablers_ref_head);
1266                 }
1267
1268                 /*
1269                  * Link filter bytecodes if not linked yet.
1270                  */
1271                 lttng_enabler_link_bytecode(event->desc,
1272                         &session->ctx,
1273                         &event->filter_bytecode_runtime_head,
1274                         &lttng_event_enabler_as_enabler(event_enabler)->filter_bytecode_head);
1275
1276                 /* TODO: merge event context. */
1277         }
1278 end:
1279         return 0;
1280 }
1281
1282 /*
1283  * Called at library load: connect the probe on all enablers matching
1284  * this event.
1285  * Called with session mutex held.
1286  */
1287 int lttng_fix_pending_events(void)
1288 {
1289         struct lttng_session *session;
1290
1291         cds_list_for_each_entry(session, &sessions, node) {
1292                 lttng_session_lazy_sync_event_enablers(session);
1293         }
1294         return 0;
1295 }
1296
1297 int lttng_fix_pending_event_notifiers(void)
1298 {
1299         struct lttng_event_notifier_group *event_notifier_group;
1300
1301         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1302                 lttng_event_notifier_group_sync_enablers(event_notifier_group);
1303         }
1304         return 0;
1305 }
1306
1307 /*
1308  * For each session of the owner thread, execute pending statedump.
1309  * Only dump state for the sessions owned by the caller thread, because
1310  * we don't keep ust_lock across the entire iteration.
1311  */
1312 void lttng_handle_pending_statedump(void *owner)
1313 {
1314         struct lttng_session *session;
1315
1316         /* Execute state dump */
1317         do_lttng_ust_statedump(owner);
1318
1319         /* Clear pending state dump */
1320         if (ust_lock()) {
1321                 goto end;
1322         }
1323         cds_list_for_each_entry(session, &sessions, node) {
1324                 if (session->owner != owner)
1325                         continue;
1326                 if (!session->statedump_pending)
1327                         continue;
1328                 session->statedump_pending = 0;
1329         }
1330 end:
1331         ust_unlock();
1332         return;
1333 }
1334
1335 /*
1336  * Only used internally at session destruction.
1337  */
1338 static
1339 void _lttng_event_destroy(struct lttng_event *event)
1340 {
1341         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1342
1343         /* Remove from event list. */
1344         cds_list_del(&event->node);
1345         /* Remove from event hash table. */
1346         cds_hlist_del(&event->hlist);
1347
1348         lttng_destroy_context(event->ctx);
1349         lttng_free_event_filter_runtime(event);
1350         /* Free event enabler refs */
1351         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1352                         &event->enablers_ref_head, node)
1353                 free(enabler_ref);
1354         free(event);
1355 }
1356
1357 static
1358 void _lttng_enum_destroy(struct lttng_enum *_enum)
1359 {
1360         cds_list_del(&_enum->node);
1361         cds_hlist_del(&_enum->hlist);
1362         free(_enum);
1363 }
1364
1365 void lttng_ust_events_exit(void)
1366 {
1367         struct lttng_session *session, *tmpsession;
1368
1369         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1370                 lttng_session_destroy(session);
1371 }
1372
1373 /*
1374  * Enabler management.
1375  */
1376 struct lttng_event_enabler *lttng_event_enabler_create(
1377                 enum lttng_enabler_format_type format_type,
1378                 struct lttng_ust_event *event_param,
1379                 struct lttng_channel *chan)
1380 {
1381         struct lttng_event_enabler *event_enabler;
1382
1383         event_enabler = zmalloc(sizeof(*event_enabler));
1384         if (!event_enabler)
1385                 return NULL;
1386         event_enabler->base.format_type = format_type;
1387         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1388         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1389         memcpy(&event_enabler->base.event_param, event_param,
1390                 sizeof(event_enabler->base.event_param));
1391         event_enabler->chan = chan;
1392         /* ctx left NULL */
1393         event_enabler->base.enabled = 0;
1394         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1395         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1396
1397         return event_enabler;
1398 }
1399
1400 struct lttng_event_notifier_enabler *lttng_event_notifier_enabler_create(
1401                 struct lttng_event_notifier_group *event_notifier_group,
1402                 enum lttng_enabler_format_type format_type,
1403                 struct lttng_ust_event_notifier *event_notifier_param)
1404 {
1405         struct lttng_event_notifier_enabler *event_notifier_enabler;
1406
1407         event_notifier_enabler = zmalloc(sizeof(*event_notifier_enabler));
1408         if (!event_notifier_enabler)
1409                 return NULL;
1410         event_notifier_enabler->base.format_type = format_type;
1411         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.filter_bytecode_head);
1412         CDS_INIT_LIST_HEAD(&event_notifier_enabler->capture_bytecode_head);
1413         CDS_INIT_LIST_HEAD(&event_notifier_enabler->base.excluder_head);
1414
1415         event_notifier_enabler->user_token = event_notifier_param->event.token;
1416         event_notifier_enabler->error_counter_index = event_notifier_param->error_counter_index;
1417         event_notifier_enabler->num_captures = 0;
1418
1419         memcpy(&event_notifier_enabler->base.event_param.name,
1420                 event_notifier_param->event.name,
1421                 sizeof(event_notifier_enabler->base.event_param.name));
1422         event_notifier_enabler->base.event_param.instrumentation =
1423                 event_notifier_param->event.instrumentation;
1424         event_notifier_enabler->base.event_param.loglevel =
1425                 event_notifier_param->event.loglevel;
1426         event_notifier_enabler->base.event_param.loglevel_type =
1427                 event_notifier_param->event.loglevel_type;
1428
1429         event_notifier_enabler->base.enabled = 0;
1430         event_notifier_enabler->group = event_notifier_group;
1431
1432         cds_list_add(&event_notifier_enabler->node,
1433                         &event_notifier_group->enablers_head);
1434
1435         lttng_event_notifier_group_sync_enablers(event_notifier_group);
1436
1437         return event_notifier_enabler;
1438 }
1439
1440 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1441 {
1442         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1443         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1444
1445         return 0;
1446 }
1447
1448 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1449 {
1450         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1451         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1452
1453         return 0;
1454 }
1455
1456 static
1457 void _lttng_enabler_attach_filter_bytecode(struct lttng_enabler *enabler,
1458                 struct lttng_ust_bytecode_node *bytecode)
1459 {
1460         bytecode->enabler = enabler;
1461         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
1462 }
1463
1464 int lttng_event_enabler_attach_filter_bytecode(struct lttng_event_enabler *event_enabler,
1465                 struct lttng_ust_bytecode_node *bytecode)
1466 {
1467         _lttng_enabler_attach_filter_bytecode(
1468                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1469
1470         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1471         return 0;
1472 }
1473
1474 static
1475 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1476                 struct lttng_ust_excluder_node *excluder)
1477 {
1478         excluder->enabler = enabler;
1479         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
1480 }
1481
1482 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1483                 struct lttng_ust_excluder_node *excluder)
1484 {
1485         _lttng_enabler_attach_exclusion(
1486                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1487
1488         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1489         return 0;
1490 }
1491
1492 int lttng_event_notifier_enabler_enable(
1493                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1494 {
1495         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 1;
1496         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1497
1498         return 0;
1499 }
1500
1501 int lttng_event_notifier_enabler_disable(
1502                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1503 {
1504         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled = 0;
1505         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1506
1507         return 0;
1508 }
1509
1510 int lttng_event_notifier_enabler_attach_filter_bytecode(
1511                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1512                 struct lttng_ust_bytecode_node *bytecode)
1513 {
1514         _lttng_enabler_attach_filter_bytecode(
1515                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1516                 bytecode);
1517
1518         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1519         return 0;
1520 }
1521
1522 int lttng_event_notifier_enabler_attach_capture_bytecode(
1523                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1524                 struct lttng_ust_bytecode_node *bytecode)
1525 {
1526         bytecode->enabler = lttng_event_notifier_enabler_as_enabler(
1527                         event_notifier_enabler);
1528         cds_list_add_tail(&bytecode->node,
1529                         &event_notifier_enabler->capture_bytecode_head);
1530         event_notifier_enabler->num_captures++;
1531
1532         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1533         return 0;
1534 }
1535
1536 int lttng_event_notifier_enabler_attach_exclusion(
1537                 struct lttng_event_notifier_enabler *event_notifier_enabler,
1538                 struct lttng_ust_excluder_node *excluder)
1539 {
1540         _lttng_enabler_attach_exclusion(
1541                 lttng_event_notifier_enabler_as_enabler(event_notifier_enabler),
1542                 excluder);
1543
1544         lttng_event_notifier_group_sync_enablers(event_notifier_enabler->group);
1545         return 0;
1546 }
1547
1548 int lttng_attach_context(struct lttng_ust_context *context_param,
1549                 union ust_args *uargs,
1550                 struct lttng_ctx **ctx, struct lttng_session *session)
1551 {
1552         /*
1553          * We cannot attach a context after trace has been started for a
1554          * session because the metadata does not allow expressing this
1555          * information outside of the original channel scope.
1556          */
1557         if (session->been_active)
1558                 return -EPERM;
1559
1560         switch (context_param->ctx) {
1561         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1562                 return lttng_add_pthread_id_to_ctx(ctx);
1563         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1564         {
1565                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1566
1567                 perf_ctx_param = &context_param->u.perf_counter;
1568                 return lttng_add_perf_counter_to_ctx(
1569                         perf_ctx_param->type,
1570                         perf_ctx_param->config,
1571                         perf_ctx_param->name,
1572                         ctx);
1573         }
1574         case LTTNG_UST_CONTEXT_VTID:
1575                 return lttng_add_vtid_to_ctx(ctx);
1576         case LTTNG_UST_CONTEXT_VPID:
1577                 return lttng_add_vpid_to_ctx(ctx);
1578         case LTTNG_UST_CONTEXT_PROCNAME:
1579                 return lttng_add_procname_to_ctx(ctx);
1580         case LTTNG_UST_CONTEXT_IP:
1581                 return lttng_add_ip_to_ctx(ctx);
1582         case LTTNG_UST_CONTEXT_CPU_ID:
1583                 return lttng_add_cpu_id_to_ctx(ctx);
1584         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1585                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1586                         ctx);
1587         case LTTNG_UST_CONTEXT_CGROUP_NS:
1588                 return lttng_add_cgroup_ns_to_ctx(ctx);
1589         case LTTNG_UST_CONTEXT_IPC_NS:
1590                 return lttng_add_ipc_ns_to_ctx(ctx);
1591         case LTTNG_UST_CONTEXT_MNT_NS:
1592                 return lttng_add_mnt_ns_to_ctx(ctx);
1593         case LTTNG_UST_CONTEXT_NET_NS:
1594                 return lttng_add_net_ns_to_ctx(ctx);
1595         case LTTNG_UST_CONTEXT_PID_NS:
1596                 return lttng_add_pid_ns_to_ctx(ctx);
1597         case LTTNG_UST_CONTEXT_TIME_NS:
1598                 return lttng_add_time_ns_to_ctx(ctx);
1599         case LTTNG_UST_CONTEXT_USER_NS:
1600                 return lttng_add_user_ns_to_ctx(ctx);
1601         case LTTNG_UST_CONTEXT_UTS_NS:
1602                 return lttng_add_uts_ns_to_ctx(ctx);
1603         case LTTNG_UST_CONTEXT_VUID:
1604                 return lttng_add_vuid_to_ctx(ctx);
1605         case LTTNG_UST_CONTEXT_VEUID:
1606                 return lttng_add_veuid_to_ctx(ctx);
1607         case LTTNG_UST_CONTEXT_VSUID:
1608                 return lttng_add_vsuid_to_ctx(ctx);
1609         case LTTNG_UST_CONTEXT_VGID:
1610                 return lttng_add_vgid_to_ctx(ctx);
1611         case LTTNG_UST_CONTEXT_VEGID:
1612                 return lttng_add_vegid_to_ctx(ctx);
1613         case LTTNG_UST_CONTEXT_VSGID:
1614                 return lttng_add_vsgid_to_ctx(ctx);
1615         default:
1616                 return -EINVAL;
1617         }
1618 }
1619
1620 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1621                 struct lttng_ust_context *context_param)
1622 {
1623         return -ENOSYS;
1624 }
1625
1626 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1627 {
1628         if (!event_enabler) {
1629                 return;
1630         }
1631         cds_list_del(&event_enabler->node);
1632
1633         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1634
1635         lttng_destroy_context(event_enabler->ctx);
1636         free(event_enabler);
1637 }
1638
1639 /*
1640  * lttng_session_sync_event_enablers should be called just before starting a
1641  * session.
1642  */
1643 static
1644 void lttng_session_sync_event_enablers(struct lttng_session *session)
1645 {
1646         struct lttng_event_enabler *event_enabler;
1647         struct lttng_event *event;
1648
1649         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1650                 lttng_event_enabler_ref_events(event_enabler);
1651         /*
1652          * For each event, if at least one of its enablers is enabled,
1653          * and its channel and session transient states are enabled, we
1654          * enable the event, else we disable it.
1655          */
1656         cds_list_for_each_entry(event, &session->events_head, node) {
1657                 struct lttng_enabler_ref *enabler_ref;
1658                 struct lttng_bytecode_runtime *runtime;
1659                 int enabled = 0, has_enablers_without_bytecode = 0;
1660
1661                 /* Enable events */
1662                 cds_list_for_each_entry(enabler_ref,
1663                                 &event->enablers_ref_head, node) {
1664                         if (enabler_ref->ref->enabled) {
1665                                 enabled = 1;
1666                                 break;
1667                         }
1668                 }
1669                 /*
1670                  * Enabled state is based on union of enablers, with
1671                  * intesection of session and channel transient enable
1672                  * states.
1673                  */
1674                 enabled = enabled && session->tstate && event->chan->tstate;
1675
1676                 CMM_STORE_SHARED(event->enabled, enabled);
1677                 /*
1678                  * Sync tracepoint registration with event enabled
1679                  * state.
1680                  */
1681                 if (enabled) {
1682                         if (!event->registered)
1683                                 register_event(event);
1684                 } else {
1685                         if (event->registered)
1686                                 unregister_event(event);
1687                 }
1688
1689                 /* Check if has enablers without bytecode enabled */
1690                 cds_list_for_each_entry(enabler_ref,
1691                                 &event->enablers_ref_head, node) {
1692                         if (enabler_ref->ref->enabled
1693                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1694                                 has_enablers_without_bytecode = 1;
1695                                 break;
1696                         }
1697                 }
1698                 event->has_enablers_without_bytecode =
1699                         has_enablers_without_bytecode;
1700
1701                 /* Enable filters */
1702                 cds_list_for_each_entry(runtime,
1703                                 &event->filter_bytecode_runtime_head, node) {
1704                         lttng_bytecode_filter_sync_state(runtime);
1705                 }
1706         }
1707         __tracepoint_probe_prune_release_queue();
1708 }
1709
1710 static
1711 void lttng_create_event_notifier_if_missing(
1712                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1713 {
1714         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1715         struct lttng_probe_desc *probe_desc;
1716         struct cds_list_head *probe_list;
1717         int i;
1718
1719         probe_list = lttng_get_probe_list_head();
1720
1721         cds_list_for_each_entry(probe_desc, probe_list, head) {
1722                 for (i = 0; i < probe_desc->nr_events; i++) {
1723                         int ret;
1724                         bool found = false;
1725                         const struct lttng_event_desc *desc;
1726                         struct lttng_event_notifier *event_notifier;
1727                         struct cds_hlist_head *head;
1728                         struct cds_hlist_node *node;
1729
1730                         desc = probe_desc->event_desc[i];
1731
1732                         if (!lttng_desc_match_enabler(desc,
1733                                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)))
1734                                 continue;
1735
1736                         /*
1737                          * Given the current event_notifier group, get the bucket that
1738                          * the target event_notifier would be if it was already
1739                          * created.
1740                          */
1741                         head = borrow_hash_table_bucket(
1742                                 event_notifier_group->event_notifiers_ht.table,
1743                                 LTTNG_UST_EVENT_NOTIFIER_HT_SIZE, desc);
1744
1745                         cds_hlist_for_each_entry(event_notifier, node, head, hlist) {
1746                                 /*
1747                                  * Check if event_notifier already exists by checking
1748                                  * if the event_notifier and enabler share the same
1749                                  * description and id.
1750                                  */
1751                                 if (event_notifier->desc == desc &&
1752                                                 event_notifier->user_token == event_notifier_enabler->user_token) {
1753                                         found = true;
1754                                         break;
1755                                 }
1756                         }
1757
1758                         if (found)
1759                                 continue;
1760
1761                         /*
1762                          * We need to create a event_notifier for this event probe.
1763                          */
1764                         ret = lttng_event_notifier_create(desc,
1765                                 event_notifier_enabler->user_token,
1766                                 event_notifier_enabler->error_counter_index,
1767                                 event_notifier_group);
1768                         if (ret) {
1769                                 DBG("Unable to create event_notifier %s, error %d\n",
1770                                         probe_desc->event_desc[i]->name, ret);
1771                         }
1772                 }
1773         }
1774 }
1775
1776 /*
1777  * Create event_notifiers associated with a event_notifier enabler (if not already present).
1778  */
1779 static
1780 int lttng_event_notifier_enabler_ref_event_notifiers(
1781                 struct lttng_event_notifier_enabler *event_notifier_enabler)
1782 {
1783         struct lttng_event_notifier_group *event_notifier_group = event_notifier_enabler->group;
1784         struct lttng_event_notifier *event_notifier;
1785
1786          /*
1787           * Only try to create event_notifiers for enablers that are enabled, the user
1788           * might still be attaching filter or exclusion to the
1789           * event_notifier_enabler.
1790           */
1791         if (!lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->enabled)
1792                 goto end;
1793
1794         /* First, ensure that probe event_notifiers are created for this enabler. */
1795         lttng_create_event_notifier_if_missing(event_notifier_enabler);
1796
1797         /* Link the created event_notifier with its associated enabler. */
1798         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1799                 struct lttng_enabler_ref *enabler_ref;
1800
1801                 if (!lttng_event_notifier_enabler_match_event_notifier(event_notifier_enabler, event_notifier))
1802                         continue;
1803
1804                 enabler_ref = lttng_enabler_ref(&event_notifier->enablers_ref_head,
1805                         lttng_event_notifier_enabler_as_enabler(event_notifier_enabler));
1806                 if (!enabler_ref) {
1807                         /*
1808                          * If no backward ref, create it.
1809                          * Add backward ref from event_notifier to enabler.
1810                          */
1811                         enabler_ref = zmalloc(sizeof(*enabler_ref));
1812                         if (!enabler_ref)
1813                                 return -ENOMEM;
1814
1815                         enabler_ref->ref = lttng_event_notifier_enabler_as_enabler(
1816                                 event_notifier_enabler);
1817                         cds_list_add(&enabler_ref->node,
1818                                 &event_notifier->enablers_ref_head);
1819                 }
1820
1821                 /*
1822                  * Link filter bytecodes if not linked yet.
1823                  */
1824                 lttng_enabler_link_bytecode(event_notifier->desc,
1825                         &event_notifier_group->ctx,
1826                         &event_notifier->filter_bytecode_runtime_head,
1827                         &lttng_event_notifier_enabler_as_enabler(event_notifier_enabler)->filter_bytecode_head);
1828
1829                 /*
1830                  * Link capture bytecodes if not linked yet.
1831                  */
1832                 lttng_enabler_link_bytecode(event_notifier->desc,
1833                         &event_notifier_group->ctx, &event_notifier->capture_bytecode_runtime_head,
1834                         &event_notifier_enabler->capture_bytecode_head);
1835
1836                 event_notifier->num_captures = event_notifier_enabler->num_captures;
1837         }
1838 end:
1839         return 0;
1840 }
1841
1842 static
1843 void lttng_event_notifier_group_sync_enablers(struct lttng_event_notifier_group *event_notifier_group)
1844 {
1845         struct lttng_event_notifier_enabler *event_notifier_enabler;
1846         struct lttng_event_notifier *event_notifier;
1847
1848         cds_list_for_each_entry(event_notifier_enabler, &event_notifier_group->enablers_head, node)
1849                 lttng_event_notifier_enabler_ref_event_notifiers(event_notifier_enabler);
1850
1851         /*
1852          * For each event_notifier, if at least one of its enablers is enabled,
1853          * we enable the event_notifier, else we disable it.
1854          */
1855         cds_list_for_each_entry(event_notifier, &event_notifier_group->event_notifiers_head, node) {
1856                 struct lttng_enabler_ref *enabler_ref;
1857                 struct lttng_bytecode_runtime *runtime;
1858                 int enabled = 0, has_enablers_without_bytecode = 0;
1859
1860                 /* Enable event_notifiers */
1861                 cds_list_for_each_entry(enabler_ref,
1862                                 &event_notifier->enablers_ref_head, node) {
1863                         if (enabler_ref->ref->enabled) {
1864                                 enabled = 1;
1865                                 break;
1866                         }
1867                 }
1868
1869                 CMM_STORE_SHARED(event_notifier->enabled, enabled);
1870                 /*
1871                  * Sync tracepoint registration with event_notifier enabled
1872                  * state.
1873                  */
1874                 if (enabled) {
1875                         if (!event_notifier->registered)
1876                                 register_event_notifier(event_notifier);
1877                 } else {
1878                         if (event_notifier->registered)
1879                                 unregister_event_notifier(event_notifier);
1880                 }
1881
1882                 /* Check if has enablers without bytecode enabled */
1883                 cds_list_for_each_entry(enabler_ref,
1884                                 &event_notifier->enablers_ref_head, node) {
1885                         if (enabler_ref->ref->enabled
1886                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1887                                 has_enablers_without_bytecode = 1;
1888                                 break;
1889                         }
1890                 }
1891                 event_notifier->has_enablers_without_bytecode =
1892                         has_enablers_without_bytecode;
1893
1894                 /* Enable filters */
1895                 cds_list_for_each_entry(runtime,
1896                                 &event_notifier->filter_bytecode_runtime_head, node) {
1897                         lttng_bytecode_filter_sync_state(runtime);
1898                 }
1899
1900                 /* Enable captures. */
1901                 cds_list_for_each_entry(runtime,
1902                                 &event_notifier->capture_bytecode_runtime_head, node) {
1903                         lttng_bytecode_capture_sync_state(runtime);
1904                 }
1905         }
1906         __tracepoint_probe_prune_release_queue();
1907 }
1908
1909 /*
1910  * Apply enablers to session events, adding events to session if need
1911  * be. It is required after each modification applied to an active
1912  * session, and right before session "start".
1913  * "lazy" sync means we only sync if required.
1914  */
1915 static
1916 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1917 {
1918         /* We can skip if session is not active */
1919         if (!session->active)
1920                 return;
1921         lttng_session_sync_event_enablers(session);
1922 }
1923
1924 /*
1925  * Update all sessions with the given app context.
1926  * Called with ust lock held.
1927  * This is invoked when an application context gets loaded/unloaded. It
1928  * ensures the context callbacks are in sync with the application
1929  * context (either app context callbacks, or dummy callbacks).
1930  */
1931 void lttng_ust_context_set_session_provider(const char *name,
1932                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1933                 void (*record)(struct lttng_ctx_field *field,
1934                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1935                         struct lttng_channel *chan),
1936                 void (*get_value)(struct lttng_ctx_field *field,
1937                         struct lttng_ctx_value *value))
1938 {
1939         struct lttng_session *session;
1940
1941         cds_list_for_each_entry(session, &sessions, node) {
1942                 struct lttng_channel *chan;
1943                 struct lttng_event *event;
1944                 int ret;
1945
1946                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1947                                 name, get_size, record, get_value);
1948                 if (ret)
1949                         abort();
1950                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1951                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1952                                         name, get_size, record, get_value);
1953                         if (ret)
1954                                 abort();
1955                 }
1956                 cds_list_for_each_entry(event, &session->events_head, node) {
1957                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1958                                         name, get_size, record, get_value);
1959                         if (ret)
1960                                 abort();
1961                 }
1962         }
1963 }
1964
1965 /*
1966  * Update all event_notifier groups with the given app context.
1967  * Called with ust lock held.
1968  * This is invoked when an application context gets loaded/unloaded. It
1969  * ensures the context callbacks are in sync with the application
1970  * context (either app context callbacks, or dummy callbacks).
1971  */
1972 void lttng_ust_context_set_event_notifier_group_provider(const char *name,
1973                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1974                 void (*record)(struct lttng_ctx_field *field,
1975                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1976                         struct lttng_channel *chan),
1977                 void (*get_value)(struct lttng_ctx_field *field,
1978                         struct lttng_ctx_value *value))
1979 {
1980         struct lttng_event_notifier_group *event_notifier_group;
1981
1982         cds_list_for_each_entry(event_notifier_group, &event_notifier_groups, node) {
1983                 int ret;
1984
1985                 ret = lttng_ust_context_set_provider_rcu(
1986                                 &event_notifier_group->ctx,
1987                                 name, get_size, record, get_value);
1988                 if (ret)
1989                         abort();
1990         }
1991 }