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 <urcu/list.h>
  26 #include <urcu/hlist.h>
  27 #include <pthread.h>
  28 #include <errno.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 <lttng/ust-endian.h>
  37 #include "clock.h"
  38
  39 #include <urcu-bp.h>
  40 #include <urcu/compiler.h>
  41 #include <urcu/uatomic.h>
  42 #include <urcu/arch.h>
  43
  44 #include <lttng/tracepoint.h>
  45 #include <lttng/ust-events.h>
  46
  47 #include <usterr-signal-safe.h>
  48 #include <helper.h>
  49 #include <lttng/ust-ctl.h>
  50 #include <ust-comm.h>
  51 #include <lttng/ust-dynamic-type.h>
  52 #include <lttng/ust-context-provider.h>
  53 #include "error.h"
  54 #include "compat.h"
  55 #include "lttng-ust-uuid.h"
  56
  57 #include "tracepoint-internal.h"
  58 #include "string-utils.h"
  59 #include "lttng-tracer.h"
  60 #include "lttng-tracer-core.h"
  61 #include "lttng-ust-statedump.h"
  62 #include "ust-events-internal.h"
  63 #include "wait.h"
  64 #include "../libringbuffer/shm.h"
  65 #include "jhash.h"
  66
  67 /*
  68  * All operations within this file are called by the communication
  69  * thread, under ust_lock protection.
  70  */
  71
  72 static CDS_LIST_HEAD(sessions);
  73
  74 struct cds_list_head *_lttng_get_sessions(void)
  75 {
  76         return &sessions;
  77 }
  78
  79 static void _lttng_event_destroy(struct lttng_event *event);
  80 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  81
  82 static
  83 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session);
  84 static
  85 void lttng_session_sync_event_enablers(struct lttng_session *session);
  86 static
  87 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  88
  89 /*
  90  * Called with ust lock held.
  91  */
  92 int lttng_session_active(void)
  93 {
  94         struct lttng_session *iter;
  95
  96         cds_list_for_each_entry(iter, &sessions, node) {
  97                 if (iter->active)
  98                         return 1;
  99         }
 100         return 0;
 101 }
 102
 103 static
 104 int lttng_loglevel_match(int loglevel,
 105                 unsigned int has_loglevel,
 106                 enum lttng_ust_loglevel_type req_type,
 107                 int req_loglevel)
 108 {
 109         if (!has_loglevel)
 110                 loglevel = TRACE_DEFAULT;
 111         switch (req_type) {
 112         case LTTNG_UST_LOGLEVEL_RANGE:
 113                 if (loglevel <= req_loglevel
 114                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 115                         return 1;
 116                 else
 117                         return 0;
 118         case LTTNG_UST_LOGLEVEL_SINGLE:
 119                 if (loglevel == req_loglevel
 120                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 121                         return 1;
 122                 else
 123                         return 0;
 124         case LTTNG_UST_LOGLEVEL_ALL:
 125         default:
 126                 if (loglevel <= TRACE_DEBUG)
 127                         return 1;
 128                 else
 129                         return 0;
 130         }
 131 }
 132
 133 void synchronize_trace(void)
 134 {
 135         synchronize_rcu();
 136 }
 137
 138 struct lttng_session *lttng_session_create(void)
 139 {
 140         struct lttng_session *session;
 141         int i;
 142
 143         session = zmalloc(sizeof(struct lttng_session));
 144         if (!session)
 145                 return NULL;
 146         if (lttng_session_context_init(&session->ctx)) {
 147                 free(session);
 148                 return NULL;
 149         }
 150         CDS_INIT_LIST_HEAD(&session->chan_head);
 151         CDS_INIT_LIST_HEAD(&session->events_head);
 152         CDS_INIT_LIST_HEAD(&session->enums_head);
 153         CDS_INIT_LIST_HEAD(&session->enablers_head);
 154         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 155                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 156         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 157                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 158         cds_list_add(&session->node, &sessions);
 159         return session;
 160 }
 161
 162 /*
 163  * Only used internally at session destruction.
 164  */
 165 static
 166 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 167 {
 168         struct channel *chan;
 169         struct lttng_ust_shm_handle *handle;
 170
 171         cds_list_del(&lttng_chan->node);
 172         lttng_destroy_context(lttng_chan->ctx);
 173         chan = lttng_chan->chan;
 174         handle = lttng_chan->handle;
 175         /*
 176          * note: lttng_chan is private data contained within handle. It
 177          * will be freed along with the handle.
 178          */
 179         channel_destroy(chan, handle, 0);
 180 }
 181
 182 static
 183 void register_event(struct lttng_event *event)
 184 {
 185         int ret;
 186         const struct lttng_event_desc *desc;
 187
 188         assert(event->registered == 0);
 189         desc = event->desc;
 190         ret = __tracepoint_probe_register_queue_release(desc->name,
 191                         desc->probe_callback,
 192                         event, desc->signature);
 193         WARN_ON_ONCE(ret);
 194         if (!ret)
 195                 event->registered = 1;
 196 }
 197
 198 static
 199 void unregister_event(struct lttng_event *event)
 200 {
 201         int ret;
 202         const struct lttng_event_desc *desc;
 203
 204         assert(event->registered == 1);
 205         desc = event->desc;
 206         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 207                         desc->probe_callback,
 208                         event);
 209         WARN_ON_ONCE(ret);
 210         if (!ret)
 211                 event->registered = 0;
 212 }
 213
 214 /*
 215  * Only used internally at session destruction.
 216  */
 217 static
 218 void _lttng_event_unregister(struct lttng_event *event)
 219 {
 220         if (event->registered)
 221                 unregister_event(event);
 222 }
 223
 224 void lttng_session_destroy(struct lttng_session *session)
 225 {
 226         struct lttng_channel *chan, *tmpchan;
 227         struct lttng_event *event, *tmpevent;
 228         struct lttng_enum *_enum, *tmp_enum;
 229         struct lttng_event_enabler *event_enabler, *event_tmpenabler;
 230
 231         CMM_ACCESS_ONCE(session->active) = 0;
 232         cds_list_for_each_entry(event, &session->events_head, node) {
 233                 _lttng_event_unregister(event);
 234         }
 235         synchronize_trace();    /* Wait for in-flight events to complete */
 236         __tracepoint_probe_prune_release_queue();
 237         cds_list_for_each_entry_safe(event_enabler, event_tmpenabler,
 238                         &session->enablers_head, node)
 239                 lttng_event_enabler_destroy(event_enabler);
 240         cds_list_for_each_entry_safe(event, tmpevent,
 241                         &session->events_head, node)
 242                 _lttng_event_destroy(event);
 243         cds_list_for_each_entry_safe(_enum, tmp_enum,
 244                         &session->enums_head, node)
 245                 _lttng_enum_destroy(_enum);
 246         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 247                 _lttng_channel_unmap(chan);
 248         cds_list_del(&session->node);
 249         lttng_destroy_context(session->ctx);
 250         free(session);
 251 }
 252
 253 static
 254 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 255 {
 256         struct lttng_ust_filter_bytecode_node *filter_node, *tmp_filter_node;
 257         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 258
 259         if (!enabler) {
 260                 return;
 261         }
 262
 263         /* Destroy filter bytecode */
 264         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 265                         &enabler->filter_bytecode_head, node) {
 266                 free(filter_node);
 267         }
 268
 269         /* Destroy excluders */
 270         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 271                         &enabler->excluder_head, node) {
 272                 free(excluder_node);
 273         }
 274 }
 275
 276 static
 277 int lttng_enum_create(const struct lttng_enum_desc *desc,
 278                 struct lttng_session *session)
 279 {
 280         const char *enum_name = desc->name;
 281         struct lttng_enum *_enum;
 282         struct cds_hlist_head *head;
 283         int ret = 0;
 284         size_t name_len = strlen(enum_name);
 285         uint32_t hash;
 286         int notify_socket;
 287
 288         /* Check if this enum is already registered for this session. */
 289         hash = jhash(enum_name, name_len, 0);
 290         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 291
 292         _enum = lttng_ust_enum_get_from_desc(session, desc);
 293         if (_enum) {
 294                 ret = -EEXIST;
 295                 goto exist;
 296         }
 297
 298         notify_socket = lttng_get_notify_socket(session->owner);
 299         if (notify_socket < 0) {
 300                 ret = notify_socket;
 301                 goto socket_error;
 302         }
 303
 304         _enum = zmalloc(sizeof(*_enum));
 305         if (!_enum) {
 306                 ret = -ENOMEM;
 307                 goto cache_error;
 308         }
 309         _enum->session = session;
 310         _enum->desc = desc;
 311
 312         ret = ustcomm_register_enum(notify_socket,
 313                 session->objd,
 314                 enum_name,
 315                 desc->nr_entries,
 316                 desc->entries,
 317                 &_enum->id);
 318         if (ret < 0) {
 319                 DBG("Error (%d) registering enumeration to sessiond", ret);
 320                 goto sessiond_register_error;
 321         }
 322         cds_list_add(&_enum->node, &session->enums_head);
 323         cds_hlist_add_head(&_enum->hlist, head);
 324         return 0;
 325
 326 sessiond_register_error:
 327         free(_enum);
 328 cache_error:
 329 socket_error:
 330 exist:
 331         return ret;
 332 }
 333
 334 static
 335 int lttng_create_enum_check(const struct lttng_type *type,
 336                 struct lttng_session *session)
 337 {
 338         switch (type->atype) {
 339         case atype_enum:
 340         {
 341                 const struct lttng_enum_desc *enum_desc;
 342                 int ret;
 343
 344                 enum_desc = type->u.legacy.basic.enumeration.desc;
 345                 ret = lttng_enum_create(enum_desc, session);
 346                 if (ret && ret != -EEXIST) {
 347                         DBG("Unable to create enum error: (%d)", ret);
 348                         return ret;
 349                 }
 350                 break;
 351         }
 352         case atype_enum_nestable:
 353         {
 354                 const struct lttng_enum_desc *enum_desc;
 355                 int ret;
 356
 357                 enum_desc = type->u.enum_nestable.desc;
 358                 ret = lttng_enum_create(enum_desc, session);
 359                 if (ret && ret != -EEXIST) {
 360                         DBG("Unable to create enum error: (%d)", ret);
 361                         return ret;
 362                 }
 363                 break;
 364         }
 365         case atype_dynamic:
 366         {
 367                 const struct lttng_event_field *tag_field_generic;
 368                 const struct lttng_enum_desc *enum_desc;
 369                 int ret;
 370
 371                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 372                 enum_desc = tag_field_generic->type.u.enum_nestable.desc;
 373                 ret = lttng_enum_create(enum_desc, session);
 374                 if (ret && ret != -EEXIST) {
 375                         DBG("Unable to create enum error: (%d)", ret);
 376                         return ret;
 377                 }
 378                 break;
 379         }
 380         default:
 381                 /* TODO: nested types when they become supported. */
 382                 break;
 383         }
 384         return 0;
 385 }
 386
 387 static
 388 int lttng_create_all_event_enums(size_t nr_fields,
 389                 const struct lttng_event_field *event_fields,
 390                 struct lttng_session *session)
 391 {
 392         size_t i;
 393         int ret;
 394
 395         /* For each field, ensure enum is part of the session. */
 396         for (i = 0; i < nr_fields; i++) {
 397                 const struct lttng_type *type = &event_fields[i].type;
 398
 399                 ret = lttng_create_enum_check(type, session);
 400                 if (ret)
 401                         return ret;
 402         }
 403         return 0;
 404 }
 405
 406 static
 407 int lttng_create_all_ctx_enums(size_t nr_fields,
 408                 const struct lttng_ctx_field *ctx_fields,
 409                 struct lttng_session *session)
 410 {
 411         size_t i;
 412         int ret;
 413
 414         /* For each field, ensure enum is part of the session. */
 415         for (i = 0; i < nr_fields; i++) {
 416                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 417
 418                 ret = lttng_create_enum_check(type, session);
 419                 if (ret)
 420                         return ret;
 421         }
 422         return 0;
 423 }
 424
 425 /*
 426  * Ensure that a state-dump will be performed for this session at the end
 427  * of the current handle_message().
 428  */
 429 int lttng_session_statedump(struct lttng_session *session)
 430 {
 431         session->statedump_pending = 1;
 432         lttng_ust_sockinfo_session_enabled(session->owner);
 433         return 0;
 434 }
 435
 436 int lttng_session_enable(struct lttng_session *session)
 437 {
 438         int ret = 0;
 439         struct lttng_channel *chan;
 440         int notify_socket;
 441
 442         if (session->active) {
 443                 ret = -EBUSY;
 444                 goto end;
 445         }
 446
 447         notify_socket = lttng_get_notify_socket(session->owner);
 448         if (notify_socket < 0)
 449                 return notify_socket;
 450
 451         /* Set transient enabler state to "enabled" */
 452         session->tstate = 1;
 453
 454         /* We need to sync enablers with session before activation. */
 455         lttng_session_sync_event_enablers(session);
 456
 457         /*
 458          * Snapshot the number of events per channel to know the type of header
 459          * we need to use.
 460          */
 461         cds_list_for_each_entry(chan, &session->chan_head, node) {
 462                 const struct lttng_ctx *ctx;
 463                 const struct lttng_ctx_field *fields = NULL;
 464                 size_t nr_fields = 0;
 465                 uint32_t chan_id;
 466
 467                 /* don't change it if session stop/restart */
 468                 if (chan->header_type)
 469                         continue;
 470                 ctx = chan->ctx;
 471                 if (ctx) {
 472                         nr_fields = ctx->nr_fields;
 473                         fields = ctx->fields;
 474                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 475                                 session);
 476                         if (ret < 0) {
 477                                 DBG("Error (%d) adding enum to session", ret);
 478                                 return ret;
 479                         }
 480                 }
 481                 ret = ustcomm_register_channel(notify_socket,
 482                         session,
 483                         session->objd,
 484                         chan->objd,
 485                         nr_fields,
 486                         fields,
 487                         &chan_id,
 488                         &chan->header_type);
 489                 if (ret) {
 490                         DBG("Error (%d) registering channel to sessiond", ret);
 491                         return ret;
 492                 }
 493                 if (chan_id != chan->id) {
 494                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 495                                 chan_id, chan->id);
 496                         return -EINVAL;
 497                 }
 498         }
 499
 500         /* Set atomically the state to "active" */
 501         CMM_ACCESS_ONCE(session->active) = 1;
 502         CMM_ACCESS_ONCE(session->been_active) = 1;
 503
 504         ret = lttng_session_statedump(session);
 505         if (ret)
 506                 return ret;
 507 end:
 508         return ret;
 509 }
 510
 511 int lttng_session_disable(struct lttng_session *session)
 512 {
 513         int ret = 0;
 514
 515         if (!session->active) {
 516                 ret = -EBUSY;
 517                 goto end;
 518         }
 519         /* Set atomically the state to "inactive" */
 520         CMM_ACCESS_ONCE(session->active) = 0;
 521
 522         /* Set transient enabler state to "disabled" */
 523         session->tstate = 0;
 524         lttng_session_sync_event_enablers(session);
 525 end:
 526         return ret;
 527 }
 528
 529 int lttng_channel_enable(struct lttng_channel *channel)
 530 {
 531         int ret = 0;
 532
 533         if (channel->enabled) {
 534                 ret = -EBUSY;
 535                 goto end;
 536         }
 537         /* Set transient enabler state to "enabled" */
 538         channel->tstate = 1;
 539         lttng_session_sync_event_enablers(channel->session);
 540         /* Set atomically the state to "enabled" */
 541         CMM_ACCESS_ONCE(channel->enabled) = 1;
 542 end:
 543         return ret;
 544 }
 545
 546 int lttng_channel_disable(struct lttng_channel *channel)
 547 {
 548         int ret = 0;
 549
 550         if (!channel->enabled) {
 551                 ret = -EBUSY;
 552                 goto end;
 553         }
 554         /* Set atomically the state to "disabled" */
 555         CMM_ACCESS_ONCE(channel->enabled) = 0;
 556         /* Set transient enabler state to "enabled" */
 557         channel->tstate = 0;
 558         lttng_session_sync_event_enablers(channel->session);
 559 end:
 560         return ret;
 561 }
 562
 563 /*
 564  * Supports event creation while tracing session is active.
 565  */
 566 static
 567 int lttng_event_create(const struct lttng_event_desc *desc,
 568                 struct lttng_channel *chan)
 569 {
 570         const char *event_name = desc->name;
 571         struct lttng_event *event;
 572         struct lttng_session *session = chan->session;
 573         struct cds_hlist_head *head;
 574         int ret = 0;
 575         size_t name_len = strlen(event_name);
 576         uint32_t hash;
 577         int notify_socket, loglevel;
 578         const char *uri;
 579
 580         hash = jhash(event_name, name_len, 0);
 581         head = &chan->session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 582
 583         notify_socket = lttng_get_notify_socket(session->owner);
 584         if (notify_socket < 0) {
 585                 ret = notify_socket;
 586                 goto socket_error;
 587         }
 588
 589         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 590                         session);
 591         if (ret < 0) {
 592                 DBG("Error (%d) adding enum to session", ret);
 593                 goto create_enum_error;
 594         }
 595
 596         /*
 597          * Check if loglevel match. Refuse to connect event if not.
 598          */
 599         event = zmalloc(sizeof(struct lttng_event));
 600         if (!event) {
 601                 ret = -ENOMEM;
 602                 goto cache_error;
 603         }
 604         event->chan = chan;
 605
 606         /* Event will be enabled by enabler sync. */
 607         event->enabled = 0;
 608         event->registered = 0;
 609         CDS_INIT_LIST_HEAD(&event->bytecode_runtime_head);
 610         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 611         event->desc = desc;
 612
 613         if (desc->loglevel)
 614                 loglevel = *(*event->desc->loglevel);
 615         else
 616                 loglevel = TRACE_DEFAULT;
 617         if (desc->u.ext.model_emf_uri)
 618                 uri = *(desc->u.ext.model_emf_uri);
 619         else
 620                 uri = NULL;
 621
 622         /* Fetch event ID from sessiond */
 623         ret = ustcomm_register_event(notify_socket,
 624                 session,
 625                 session->objd,
 626                 chan->objd,
 627                 event_name,
 628                 loglevel,
 629                 desc->signature,
 630                 desc->nr_fields,
 631                 desc->fields,
 632                 uri,
 633                 &event->id);
 634         if (ret < 0) {
 635                 DBG("Error (%d) registering event to sessiond", ret);
 636                 goto sessiond_register_error;
 637         }
 638
 639         cds_list_add(&event->node, &chan->session->events_head);
 640         cds_hlist_add_head(&event->hlist, head);
 641         return 0;
 642
 643 sessiond_register_error:
 644         free(event);
 645 cache_error:
 646 create_enum_error:
 647 socket_error:
 648         return ret;
 649 }
 650
 651 static
 652 int lttng_desc_match_star_glob_enabler(const struct lttng_event_desc *desc,
 653                 struct lttng_enabler *enabler)
 654 {
 655         int loglevel = 0;
 656         unsigned int has_loglevel = 0;
 657
 658         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_STAR_GLOB);
 659         if (!strutils_star_glob_match(enabler->event_param.name, SIZE_MAX,
 660                         desc->name, SIZE_MAX))
 661                 return 0;
 662         if (desc->loglevel) {
 663                 loglevel = *(*desc->loglevel);
 664                 has_loglevel = 1;
 665         }
 666         if (!lttng_loglevel_match(loglevel,
 667                         has_loglevel,
 668                         enabler->event_param.loglevel_type,
 669                         enabler->event_param.loglevel))
 670                 return 0;
 671         return 1;
 672 }
 673
 674 static
 675 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 676                 struct lttng_enabler *enabler)
 677 {
 678         int loglevel = 0;
 679         unsigned int has_loglevel = 0;
 680
 681         assert(enabler->format_type == LTTNG_ENABLER_FORMAT_EVENT);
 682         if (strcmp(desc->name, enabler->event_param.name))
 683                 return 0;
 684         if (desc->loglevel) {
 685                 loglevel = *(*desc->loglevel);
 686                 has_loglevel = 1;
 687         }
 688         if (!lttng_loglevel_match(loglevel,
 689                         has_loglevel,
 690                         enabler->event_param.loglevel_type,
 691                         enabler->event_param.loglevel))
 692                 return 0;
 693         return 1;
 694 }
 695
 696 static
 697 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 698                 struct lttng_enabler *enabler)
 699 {
 700         switch (enabler->format_type) {
 701         case LTTNG_ENABLER_FORMAT_STAR_GLOB:
 702         {
 703                 struct lttng_ust_excluder_node *excluder;
 704
 705                 if (!lttng_desc_match_star_glob_enabler(desc, enabler)) {
 706                         return 0;
 707                 }
 708
 709                 /*
 710                  * If the matching event matches with an excluder,
 711                  * return 'does not match'
 712                  */
 713                 cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 714                         int count;
 715
 716                         for (count = 0; count < excluder->excluder.count; count++) {
 717                                 int len;
 718                                 char *excluder_name;
 719
 720                                 excluder_name = (char *) (excluder->excluder.names)
 721                                                 + count * LTTNG_UST_SYM_NAME_LEN;
 722                                 len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 723                                 if (len > 0 && strutils_star_glob_match(excluder_name, len, desc->name, SIZE_MAX))
 724                                         return 0;
 725                         }
 726                 }
 727                 return 1;
 728         }
 729         case LTTNG_ENABLER_FORMAT_EVENT:
 730                 return lttng_desc_match_event_enabler(desc, enabler);
 731         default:
 732                 return -EINVAL;
 733         }
 734 }
 735
 736 static
 737 int lttng_event_enabler_match_event(struct lttng_event_enabler *event_enabler,
 738                 struct lttng_event *event)
 739 {
 740         if (lttng_desc_match_enabler(event->desc,
 741                         lttng_event_enabler_as_enabler(event_enabler))
 742                         && event->chan == event_enabler->chan)
 743                 return 1;
 744         else
 745                 return 0;
 746 }
 747
 748 static
 749 struct lttng_enabler_ref *lttng_enabler_ref(
 750                 struct cds_list_head *enabler_ref_list,
 751                 struct lttng_enabler *enabler)
 752 {
 753         struct lttng_enabler_ref *enabler_ref;
 754
 755         cds_list_for_each_entry(enabler_ref, enabler_ref_list, node) {
 756                 if (enabler_ref->ref == enabler)
 757                         return enabler_ref;
 758         }
 759         return NULL;
 760 }
 761
 762 /*
 763  * Create struct lttng_event if it is missing and present in the list of
 764  * tracepoint probes.
 765  */
 766 static
 767 void lttng_create_event_if_missing(struct lttng_event_enabler *event_enabler)
 768 {
 769         struct lttng_session *session = event_enabler->chan->session;
 770         struct lttng_probe_desc *probe_desc;
 771         const struct lttng_event_desc *desc;
 772         struct lttng_event *event;
 773         int i;
 774         struct cds_list_head *probe_list;
 775
 776         probe_list = lttng_get_probe_list_head();
 777         /*
 778          * For each probe event, if we find that a probe event matches
 779          * our enabler, create an associated lttng_event if not
 780          * already present.
 781          */
 782         cds_list_for_each_entry(probe_desc, probe_list, head) {
 783                 for (i = 0; i < probe_desc->nr_events; i++) {
 784                         int ret;
 785                         bool found = false;
 786                         struct cds_hlist_head *head;
 787                         struct cds_hlist_node *node;
 788                         const char *event_name;
 789                         size_t name_len;
 790                         uint32_t hash;
 791
 792                         desc = probe_desc->event_desc[i];
 793                         if (!lttng_desc_match_enabler(desc,
 794                                         lttng_event_enabler_as_enabler(event_enabler)))
 795                                 continue;
 796                         event_name = desc->name;
 797                         name_len = strlen(event_name);
 798
 799                         /*
 800                          * Check if already created.
 801                          */
 802                         hash = jhash(event_name, name_len, 0);
 803                         head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 804                         cds_hlist_for_each_entry(event, node, head, hlist) {
 805                                 if (event->desc == desc
 806                                                 && event->chan == event_enabler->chan) {
 807                                         found = true;
 808                                         break;
 809                                 }
 810                         }
 811                         if (found)
 812                                 continue;
 813
 814                         /*
 815                          * We need to create an event for this
 816                          * event probe.
 817                          */
 818                         ret = lttng_event_create(probe_desc->event_desc[i],
 819                                         event_enabler->chan);
 820                         if (ret) {
 821                                 DBG("Unable to create event %s, error %d\n",
 822                                         probe_desc->event_desc[i]->name, ret);
 823                         }
 824                 }
 825         }
 826 }
 827
 828 /*
 829  * Iterate over all the UST sessions to unregister and destroy all probes from
 830  * the probe provider descriptor received as argument. Must me called with the
 831  * ust_lock held.
 832  */
 833 void lttng_probe_provider_unregister_events(struct lttng_probe_desc *provider_desc)
 834 {
 835         struct cds_hlist_node *node, *tmp_node;
 836         struct cds_list_head *sessionsp;
 837         struct lttng_session *session;
 838         struct cds_hlist_head *head;
 839         struct lttng_event *event;
 840         unsigned int i, j;
 841
 842         /* Get handle on list of sessions. */
 843         sessionsp = _lttng_get_sessions();
 844
 845         /*
 846          * Iterate over all events in the probe provider descriptions and sessions
 847          * to queue the unregistration of the events.
 848          */
 849         for (i = 0; i < provider_desc->nr_events; i++) {
 850                 const struct lttng_event_desc *event_desc;
 851                 const char *event_name;
 852                 size_t name_len;
 853                 uint32_t hash;
 854
 855                 event_desc = provider_desc->event_desc[i];
 856                 event_name = event_desc->name;
 857                 name_len = strlen(event_name);
 858                 hash = jhash(event_name, name_len, 0);
 859
 860                 /* Iterate over all session to find the current event description. */
 861                 cds_list_for_each_entry(session, sessionsp, node) {
 862                         /*
 863                          * Get the list of events in the hashtable bucket and iterate to
 864                          * find the event matching this descriptor.
 865                          */
 866                         head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 867                         cds_hlist_for_each_entry(event, node, head, hlist) {
 868                                 if (event_desc == event->desc) {
 869                                         /* Queue the unregistration of this event. */
 870                                         _lttng_event_unregister(event);
 871                                         break;
 872                                 }
 873                         }
 874                 }
 875         }
 876
 877         /* Wait for grace period. */
 878         synchronize_trace();
 879         /* Prune the unregistration queue. */
 880         __tracepoint_probe_prune_release_queue();
 881
 882         /*
 883          * It is now safe to destroy the events and remove them from the event list
 884          * and hashtables.
 885          */
 886         for (i = 0; i < provider_desc->nr_events; i++) {
 887                 const struct lttng_event_desc *event_desc;
 888                 const char *event_name;
 889                 size_t name_len;
 890                 uint32_t hash;
 891
 892                 event_desc = provider_desc->event_desc[i];
 893                 event_name = event_desc->name;
 894                 name_len = strlen(event_name);
 895                 hash = jhash(event_name, name_len, 0);
 896
 897                 /* Iterate over all sessions to find the current event description. */
 898                 cds_list_for_each_entry(session, sessionsp, node) {
 899                         /*
 900                          * Get the list of events in the hashtable bucket and iterate to
 901                          * find the event matching this descriptor.
 902                          */
 903                         head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 904                         cds_hlist_for_each_entry_safe(event, node, tmp_node, head, hlist) {
 905                                 if (event_desc == event->desc) {
 906                                         /* Destroy enums of the current event. */
 907                                         for (j = 0; j < event->desc->nr_fields; j++) {
 908                                                 const struct lttng_enum_desc *enum_desc;
 909                                                 const struct lttng_event_field *field;
 910                                                 struct lttng_enum *curr_enum;
 911
 912                                                 field = &(event->desc->fields[j]);
 913                                                 switch (field->type.atype) {
 914                                                 case atype_enum:
 915                                                         enum_desc = field->type.u.legacy.basic.enumeration.desc;
 916                                                         break;
 917                                                 case atype_enum_nestable:
 918                                                         enum_desc = field->type.u.enum_nestable.desc;
 919                                                         break;
 920                                                 default:
 921                                                         continue;
 922                                                 }
 923                                                 curr_enum = lttng_ust_enum_get_from_desc(session, enum_desc);
 924                                                 if (curr_enum) {
 925                                                         _lttng_enum_destroy(curr_enum);
 926                                                 }
 927                                         }
 928
 929                                         /* Destroy event. */
 930                                         _lttng_event_destroy(event);
 931                                         break;
 932                                 }
 933                         }
 934                 }
 935         }
 936 }
 937
 938 /*
 939  * Create events associated with an enabler (if not already present),
 940  * and add backward reference from the event to the enabler.
 941  */
 942 static
 943 int lttng_event_enabler_ref_events(struct lttng_event_enabler *event_enabler)
 944 {
 945         struct lttng_session *session = event_enabler->chan->session;
 946         struct lttng_event *event;
 947
 948         if (!lttng_event_enabler_as_enabler(event_enabler)->enabled)
 949                 goto end;
 950
 951         /* First ensure that probe events are created for this enabler. */
 952         lttng_create_event_if_missing(event_enabler);
 953
 954         /* For each event matching enabler in session event list. */
 955         cds_list_for_each_entry(event, &session->events_head, node) {
 956                 struct lttng_enabler_ref *enabler_ref;
 957
 958                 if (!lttng_event_enabler_match_event(event_enabler, event))
 959                         continue;
 960
 961                 enabler_ref = lttng_enabler_ref(&event->enablers_ref_head,
 962                         lttng_event_enabler_as_enabler(event_enabler));
 963                 if (!enabler_ref) {
 964                         /*
 965                          * If no backward ref, create it.
 966                          * Add backward ref from event to enabler.
 967                          */
 968                         enabler_ref = zmalloc(sizeof(*enabler_ref));
 969                         if (!enabler_ref)
 970                                 return -ENOMEM;
 971                         enabler_ref->ref = lttng_event_enabler_as_enabler(
 972                                 event_enabler);
 973                         cds_list_add(&enabler_ref->node,
 974                                 &event->enablers_ref_head);
 975                 }
 976
 977                 /*
 978                  * Link filter bytecodes if not linked yet.
 979                  */
 980                 lttng_event_enabler_link_bytecode(event, event_enabler);
 981
 982                 /* TODO: merge event context. */
 983         }
 984 end:
 985         return 0;
 986 }
 987
 988 /*
 989  * Called at library load: connect the probe on all enablers matching
 990  * this event.
 991  * Called with session mutex held.
 992  */
 993 int lttng_fix_pending_events(void)
 994 {
 995         struct lttng_session *session;
 996
 997         cds_list_for_each_entry(session, &sessions, node) {
 998                 lttng_session_lazy_sync_event_enablers(session);
 999         }
1000         return 0;
1001 }
1002
1003 /*
1004  * For each session of the owner thread, execute pending statedump.
1005  * Only dump state for the sessions owned by the caller thread, because
1006  * we don't keep ust_lock across the entire iteration.
1007  */
1008 void lttng_handle_pending_statedump(void *owner)
1009 {
1010         struct lttng_session *session;
1011
1012         /* Execute state dump */
1013         do_lttng_ust_statedump(owner);
1014
1015         /* Clear pending state dump */
1016         if (ust_lock()) {
1017                 goto end;
1018         }
1019         cds_list_for_each_entry(session, &sessions, node) {
1020                 if (session->owner != owner)
1021                         continue;
1022                 if (!session->statedump_pending)
1023                         continue;
1024                 session->statedump_pending = 0;
1025         }
1026 end:
1027         ust_unlock();
1028         return;
1029 }
1030
1031 /*
1032  * Only used internally at session destruction.
1033  */
1034 static
1035 void _lttng_event_destroy(struct lttng_event *event)
1036 {
1037         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
1038
1039         /* Remove from event list. */
1040         cds_list_del(&event->node);
1041         /* Remove from event hash table. */
1042         cds_hlist_del(&event->hlist);
1043
1044         lttng_destroy_context(event->ctx);
1045         lttng_free_event_filter_runtime(event);
1046         /* Free event enabler refs */
1047         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
1048                         &event->enablers_ref_head, node)
1049                 free(enabler_ref);
1050         free(event);
1051 }
1052
1053 static
1054 void _lttng_enum_destroy(struct lttng_enum *_enum)
1055 {
1056         cds_list_del(&_enum->node);
1057         cds_hlist_del(&_enum->hlist);
1058         free(_enum);
1059 }
1060
1061 void lttng_ust_events_exit(void)
1062 {
1063         struct lttng_session *session, *tmpsession;
1064
1065         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
1066                 lttng_session_destroy(session);
1067 }
1068
1069 /*
1070  * Enabler management.
1071  */
1072 struct lttng_event_enabler *lttng_event_enabler_create(
1073                 enum lttng_enabler_format_type format_type,
1074                 struct lttng_ust_event *event_param,
1075                 struct lttng_channel *chan)
1076 {
1077         struct lttng_event_enabler *event_enabler;
1078
1079         event_enabler = zmalloc(sizeof(*event_enabler));
1080         if (!event_enabler)
1081                 return NULL;
1082         event_enabler->base.format_type = format_type;
1083         CDS_INIT_LIST_HEAD(&event_enabler->base.filter_bytecode_head);
1084         CDS_INIT_LIST_HEAD(&event_enabler->base.excluder_head);
1085         memcpy(&event_enabler->base.event_param, event_param,
1086                 sizeof(event_enabler->base.event_param));
1087         event_enabler->chan = chan;
1088         /* ctx left NULL */
1089         event_enabler->base.enabled = 0;
1090         cds_list_add(&event_enabler->node, &event_enabler->chan->session->enablers_head);
1091         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1092
1093         return event_enabler;
1094 }
1095
1096 int lttng_event_enabler_enable(struct lttng_event_enabler *event_enabler)
1097 {
1098         lttng_event_enabler_as_enabler(event_enabler)->enabled = 1;
1099         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1100
1101         return 0;
1102 }
1103
1104 int lttng_event_enabler_disable(struct lttng_event_enabler *event_enabler)
1105 {
1106         lttng_event_enabler_as_enabler(event_enabler)->enabled = 0;
1107         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1108
1109         return 0;
1110 }
1111
1112 static
1113 void _lttng_enabler_attach_bytecode(struct lttng_enabler *enabler,
1114                 struct lttng_ust_filter_bytecode_node *bytecode)
1115 {
1116         bytecode->enabler = enabler;
1117         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
1118 }
1119
1120 int lttng_event_enabler_attach_bytecode(struct lttng_event_enabler *event_enabler,
1121                 struct lttng_ust_filter_bytecode_node *bytecode)
1122 {
1123         _lttng_enabler_attach_bytecode(
1124                 lttng_event_enabler_as_enabler(event_enabler), bytecode);
1125
1126         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1127         return 0;
1128 }
1129
1130 static
1131 void _lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
1132                 struct lttng_ust_excluder_node *excluder)
1133 {
1134         excluder->enabler = enabler;
1135         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
1136 }
1137
1138 int lttng_event_enabler_attach_exclusion(struct lttng_event_enabler *event_enabler,
1139                 struct lttng_ust_excluder_node *excluder)
1140 {
1141         _lttng_enabler_attach_exclusion(
1142                 lttng_event_enabler_as_enabler(event_enabler), excluder);
1143
1144         lttng_session_lazy_sync_event_enablers(event_enabler->chan->session);
1145         return 0;
1146 }
1147
1148 int lttng_attach_context(struct lttng_ust_context *context_param,
1149                 union ust_args *uargs,
1150                 struct lttng_ctx **ctx, struct lttng_session *session)
1151 {
1152         /*
1153          * We cannot attach a context after trace has been started for a
1154          * session because the metadata does not allow expressing this
1155          * information outside of the original channel scope.
1156          */
1157         if (session->been_active)
1158                 return -EPERM;
1159
1160         switch (context_param->ctx) {
1161         case LTTNG_UST_CONTEXT_PTHREAD_ID:
1162                 return lttng_add_pthread_id_to_ctx(ctx);
1163         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
1164         {
1165                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
1166
1167                 perf_ctx_param = &context_param->u.perf_counter;
1168                 return lttng_add_perf_counter_to_ctx(
1169                         perf_ctx_param->type,
1170                         perf_ctx_param->config,
1171                         perf_ctx_param->name,
1172                         ctx);
1173         }
1174         case LTTNG_UST_CONTEXT_VTID:
1175                 return lttng_add_vtid_to_ctx(ctx);
1176         case LTTNG_UST_CONTEXT_VPID:
1177                 return lttng_add_vpid_to_ctx(ctx);
1178         case LTTNG_UST_CONTEXT_PROCNAME:
1179                 return lttng_add_procname_to_ctx(ctx);
1180         case LTTNG_UST_CONTEXT_IP:
1181                 return lttng_add_ip_to_ctx(ctx);
1182         case LTTNG_UST_CONTEXT_CPU_ID:
1183                 return lttng_add_cpu_id_to_ctx(ctx);
1184         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1185                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1186                         ctx);
1187         case LTTNG_UST_CONTEXT_CGROUP_NS:
1188                 return lttng_add_cgroup_ns_to_ctx(ctx);
1189         case LTTNG_UST_CONTEXT_IPC_NS:
1190                 return lttng_add_ipc_ns_to_ctx(ctx);
1191         case LTTNG_UST_CONTEXT_MNT_NS:
1192                 return lttng_add_mnt_ns_to_ctx(ctx);
1193         case LTTNG_UST_CONTEXT_NET_NS:
1194                 return lttng_add_net_ns_to_ctx(ctx);
1195         case LTTNG_UST_CONTEXT_PID_NS:
1196                 return lttng_add_pid_ns_to_ctx(ctx);
1197         case LTTNG_UST_CONTEXT_TIME_NS:
1198                 return lttng_add_time_ns_to_ctx(ctx);
1199         case LTTNG_UST_CONTEXT_USER_NS:
1200                 return lttng_add_user_ns_to_ctx(ctx);
1201         case LTTNG_UST_CONTEXT_UTS_NS:
1202                 return lttng_add_uts_ns_to_ctx(ctx);
1203         case LTTNG_UST_CONTEXT_VUID:
1204                 return lttng_add_vuid_to_ctx(ctx);
1205         case LTTNG_UST_CONTEXT_VEUID:
1206                 return lttng_add_veuid_to_ctx(ctx);
1207         case LTTNG_UST_CONTEXT_VSUID:
1208                 return lttng_add_vsuid_to_ctx(ctx);
1209         case LTTNG_UST_CONTEXT_VGID:
1210                 return lttng_add_vgid_to_ctx(ctx);
1211         case LTTNG_UST_CONTEXT_VEGID:
1212                 return lttng_add_vegid_to_ctx(ctx);
1213         case LTTNG_UST_CONTEXT_VSGID:
1214                 return lttng_add_vsgid_to_ctx(ctx);
1215         default:
1216                 return -EINVAL;
1217         }
1218 }
1219
1220 int lttng_event_enabler_attach_context(struct lttng_event_enabler *enabler,
1221                 struct lttng_ust_context *context_param)
1222 {
1223         return -ENOSYS;
1224 }
1225
1226 void lttng_event_enabler_destroy(struct lttng_event_enabler *event_enabler)
1227 {
1228         if (!event_enabler) {
1229                 return;
1230         }
1231         cds_list_del(&event_enabler->node);
1232
1233         lttng_enabler_destroy(lttng_event_enabler_as_enabler(event_enabler));
1234
1235         lttng_destroy_context(event_enabler->ctx);
1236         free(event_enabler);
1237 }
1238
1239 /*
1240  * lttng_session_sync_event_enablers should be called just before starting a
1241  * session.
1242  */
1243 static
1244 void lttng_session_sync_event_enablers(struct lttng_session *session)
1245 {
1246         struct lttng_event_enabler *event_enabler;
1247         struct lttng_event *event;
1248
1249         cds_list_for_each_entry(event_enabler, &session->enablers_head, node)
1250                 lttng_event_enabler_ref_events(event_enabler);
1251         /*
1252          * For each event, if at least one of its enablers is enabled,
1253          * and its channel and session transient states are enabled, we
1254          * enable the event, else we disable it.
1255          */
1256         cds_list_for_each_entry(event, &session->events_head, node) {
1257                 struct lttng_enabler_ref *enabler_ref;
1258                 struct lttng_bytecode_runtime *runtime;
1259                 int enabled = 0, has_enablers_without_bytecode = 0;
1260
1261                 /* Enable events */
1262                 cds_list_for_each_entry(enabler_ref,
1263                                 &event->enablers_ref_head, node) {
1264                         if (enabler_ref->ref->enabled) {
1265                                 enabled = 1;
1266                                 break;
1267                         }
1268                 }
1269                 /*
1270                  * Enabled state is based on union of enablers, with
1271                  * intesection of session and channel transient enable
1272                  * states.
1273                  */
1274                 enabled = enabled && session->tstate && event->chan->tstate;
1275
1276                 CMM_STORE_SHARED(event->enabled, enabled);
1277                 /*
1278                  * Sync tracepoint registration with event enabled
1279                  * state.
1280                  */
1281                 if (enabled) {
1282                         if (!event->registered)
1283                                 register_event(event);
1284                 } else {
1285                         if (event->registered)
1286                                 unregister_event(event);
1287                 }
1288
1289                 /* Check if has enablers without bytecode enabled */
1290                 cds_list_for_each_entry(enabler_ref,
1291                                 &event->enablers_ref_head, node) {
1292                         if (enabler_ref->ref->enabled
1293                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1294                                 has_enablers_without_bytecode = 1;
1295                                 break;
1296                         }
1297                 }
1298                 event->has_enablers_without_bytecode =
1299                         has_enablers_without_bytecode;
1300
1301                 /* Enable filters */
1302                 cds_list_for_each_entry(runtime,
1303                                 &event->bytecode_runtime_head, node) {
1304                         lttng_filter_sync_state(runtime);
1305                 }
1306         }
1307         __tracepoint_probe_prune_release_queue();
1308 }
1309
1310 /*
1311  * Apply enablers to session events, adding events to session if need
1312  * be. It is required after each modification applied to an active
1313  * session, and right before session "start".
1314  * "lazy" sync means we only sync if required.
1315  */
1316 static
1317 void lttng_session_lazy_sync_event_enablers(struct lttng_session *session)
1318 {
1319         /* We can skip if session is not active */
1320         if (!session->active)
1321                 return;
1322         lttng_session_sync_event_enablers(session);
1323 }
1324
1325 /*
1326  * Update all sessions with the given app context.
1327  * Called with ust lock held.
1328  * This is invoked when an application context gets loaded/unloaded. It
1329  * ensures the context callbacks are in sync with the application
1330  * context (either app context callbacks, or dummy callbacks).
1331  */
1332 void lttng_ust_context_set_session_provider(const char *name,
1333                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1334                 void (*record)(struct lttng_ctx_field *field,
1335                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1336                         struct lttng_channel *chan),
1337                 void (*get_value)(struct lttng_ctx_field *field,
1338                         struct lttng_ctx_value *value))
1339 {
1340         struct lttng_session *session;
1341
1342         cds_list_for_each_entry(session, &sessions, node) {
1343                 struct lttng_channel *chan;
1344                 struct lttng_event *event;
1345                 int ret;
1346
1347                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1348                                 name, get_size, record, get_value);
1349                 if (ret)
1350                         abort();
1351                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1352                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1353                                         name, get_size, record, get_value);
1354                         if (ret)
1355                                 abort();
1356                 }
1357                 cds_list_for_each_entry(event, &session->events_head, node) {
1358                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1359                                         name, get_size, record, get_value);
1360                         if (ret)
1361                                 abort();
1362                 }
1363         }
1364 }