liblttng-ust/lttng-events.c

   1 /*
   2  * lttng-events.c
   3  *
   4  * Holds LTTng per-session event registry.
   5  *
   6  * Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; only
  11  * version 2.1 of the License.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _GNU_SOURCE
  24 #define _LGPL_SOURCE
  25 #include <stdio.h>
  26 #include <urcu/list.h>
  27 #include <urcu/hlist.h>
  28 #include <pthread.h>
  29 #include <errno.h>
  30 #include <sys/shm.h>
  31 #include <sys/ipc.h>
  32 #include <stdint.h>
  33 #include <stddef.h>
  34 #include <inttypes.h>
  35 #include <time.h>
  36 #include <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 "lttng-tracer.h"
  59 #include "lttng-tracer-core.h"
  60 #include "lttng-ust-statedump.h"
  61 #include "wait.h"
  62 #include "../libringbuffer/shm.h"
  63 #include "jhash.h"
  64
  65 /*
  66  * All operations within this file are called by the communication
  67  * thread, under ust_lock protection.
  68  */
  69
  70 static CDS_LIST_HEAD(sessions);
  71
  72 struct cds_list_head *_lttng_get_sessions(void)
  73 {
  74         return &sessions;
  75 }
  76
  77 static void _lttng_event_destroy(struct lttng_event *event);
  78 static void _lttng_enum_destroy(struct lttng_enum *_enum);
  79
  80 static
  81 void lttng_session_lazy_sync_enablers(struct lttng_session *session);
  82 static
  83 void lttng_session_sync_enablers(struct lttng_session *session);
  84 static
  85 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  86
  87 /*
  88  * Called with ust lock held.
  89  */
  90 int lttng_session_active(void)
  91 {
  92         struct lttng_session *iter;
  93
  94         cds_list_for_each_entry(iter, &sessions, node) {
  95                 if (iter->active)
  96                         return 1;
  97         }
  98         return 0;
  99 }
 100
 101 static
 102 int lttng_loglevel_match(int loglevel,
 103                 unsigned int has_loglevel,
 104                 enum lttng_ust_loglevel_type req_type,
 105                 int req_loglevel)
 106 {
 107         if (!has_loglevel)
 108                 loglevel = TRACE_DEFAULT;
 109         switch (req_type) {
 110         case LTTNG_UST_LOGLEVEL_RANGE:
 111                 if (loglevel <= req_loglevel
 112                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 113                         return 1;
 114                 else
 115                         return 0;
 116         case LTTNG_UST_LOGLEVEL_SINGLE:
 117                 if (loglevel == req_loglevel
 118                                 || (req_loglevel == -1 && loglevel <= TRACE_DEBUG))
 119                         return 1;
 120                 else
 121                         return 0;
 122         case LTTNG_UST_LOGLEVEL_ALL:
 123         default:
 124                 if (loglevel <= TRACE_DEBUG)
 125                         return 1;
 126                 else
 127                         return 0;
 128         }
 129 }
 130
 131 void synchronize_trace(void)
 132 {
 133         synchronize_rcu();
 134 }
 135
 136 struct lttng_session *lttng_session_create(void)
 137 {
 138         struct lttng_session *session;
 139         int i;
 140
 141         session = zmalloc(sizeof(struct lttng_session));
 142         if (!session)
 143                 return NULL;
 144         if (lttng_session_context_init(&session->ctx)) {
 145                 free(session);
 146                 return NULL;
 147         }
 148         CDS_INIT_LIST_HEAD(&session->chan_head);
 149         CDS_INIT_LIST_HEAD(&session->events_head);
 150         CDS_INIT_LIST_HEAD(&session->enums_head);
 151         CDS_INIT_LIST_HEAD(&session->enablers_head);
 152         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 153                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 154         for (i = 0; i < LTTNG_UST_ENUM_HT_SIZE; i++)
 155                 CDS_INIT_HLIST_HEAD(&session->enums_ht.table[i]);
 156         cds_list_add(&session->node, &sessions);
 157         return session;
 158 }
 159
 160 /*
 161  * Only used internally at session destruction.
 162  */
 163 static
 164 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 165 {
 166         struct channel *chan;
 167         struct lttng_ust_shm_handle *handle;
 168
 169         cds_list_del(&lttng_chan->node);
 170         lttng_destroy_context(lttng_chan->ctx);
 171         chan = lttng_chan->chan;
 172         handle = lttng_chan->handle;
 173         /*
 174          * note: lttng_chan is private data contained within handle. It
 175          * will be freed along with the handle.
 176          */
 177         channel_destroy(chan, handle, 0);
 178 }
 179
 180 static
 181 void register_event(struct lttng_event *event)
 182 {
 183         int ret;
 184         const struct lttng_event_desc *desc;
 185
 186         assert(event->registered == 0);
 187         desc = event->desc;
 188         ret = __tracepoint_probe_register_queue_release(desc->name,
 189                         desc->probe_callback,
 190                         event, desc->signature);
 191         WARN_ON_ONCE(ret);
 192         if (!ret)
 193                 event->registered = 1;
 194 }
 195
 196 static
 197 void unregister_event(struct lttng_event *event)
 198 {
 199         int ret;
 200         const struct lttng_event_desc *desc;
 201
 202         assert(event->registered == 1);
 203         desc = event->desc;
 204         ret = __tracepoint_probe_unregister_queue_release(desc->name,
 205                         desc->probe_callback,
 206                         event);
 207         WARN_ON_ONCE(ret);
 208         if (!ret)
 209                 event->registered = 0;
 210 }
 211
 212 /*
 213  * Only used internally at session destruction.
 214  */
 215 static
 216 void _lttng_event_unregister(struct lttng_event *event)
 217 {
 218         if (event->registered)
 219                 unregister_event(event);
 220 }
 221
 222 void lttng_session_destroy(struct lttng_session *session)
 223 {
 224         struct lttng_channel *chan, *tmpchan;
 225         struct lttng_event *event, *tmpevent;
 226         struct lttng_enum *_enum, *tmp_enum;
 227         struct lttng_enabler *enabler, *tmpenabler;
 228
 229         CMM_ACCESS_ONCE(session->active) = 0;
 230         cds_list_for_each_entry(event, &session->events_head, node) {
 231                 _lttng_event_unregister(event);
 232         }
 233         synchronize_trace();    /* Wait for in-flight events to complete */
 234         __tracepoint_probe_prune_release_queue();
 235         cds_list_for_each_entry_safe(enabler, tmpenabler,
 236                         &session->enablers_head, node)
 237                 lttng_enabler_destroy(enabler);
 238         cds_list_for_each_entry_safe(event, tmpevent,
 239                         &session->events_head, node)
 240                 _lttng_event_destroy(event);
 241         cds_list_for_each_entry_safe(_enum, tmp_enum,
 242                         &session->enums_head, node)
 243                 _lttng_enum_destroy(_enum);
 244         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 245                 _lttng_channel_unmap(chan);
 246         cds_list_del(&session->node);
 247         lttng_destroy_context(session->ctx);
 248         free(session);
 249 }
 250
 251 static
 252 int lttng_enum_create(const struct lttng_enum_desc *desc,
 253                 struct lttng_session *session)
 254 {
 255         const char *enum_name = desc->name;
 256         struct lttng_enum *_enum;
 257         struct cds_hlist_head *head;
 258         struct cds_hlist_node *node;
 259         int ret = 0;
 260         size_t name_len = strlen(enum_name);
 261         uint32_t hash;
 262         int notify_socket;
 263
 264         hash = jhash(enum_name, name_len, 0);
 265         head = &session->enums_ht.table[hash & (LTTNG_UST_ENUM_HT_SIZE - 1)];
 266         cds_hlist_for_each_entry(_enum, node, head, hlist) {
 267                 assert(_enum->desc);
 268                 if (!strncmp(_enum->desc->name, desc->name,
 269                                 LTTNG_UST_SYM_NAME_LEN - 1)) {
 270                         ret = -EEXIST;
 271                         goto exist;
 272                 }
 273         }
 274
 275         notify_socket = lttng_get_notify_socket(session->owner);
 276         if (notify_socket < 0) {
 277                 ret = notify_socket;
 278                 goto socket_error;
 279         }
 280
 281         _enum = zmalloc(sizeof(*_enum));
 282         if (!_enum) {
 283                 ret = -ENOMEM;
 284                 goto cache_error;
 285         }
 286         _enum->session = session;
 287         _enum->desc = desc;
 288
 289         ret = ustcomm_register_enum(notify_socket,
 290                 session->objd,
 291                 enum_name,
 292                 desc->nr_entries,
 293                 desc->entries,
 294                 &_enum->id);
 295         if (ret < 0) {
 296                 DBG("Error (%d) registering enumeration to sessiond", ret);
 297                 goto sessiond_register_error;
 298         }
 299         cds_list_add(&_enum->node, &session->enums_head);
 300         cds_hlist_add_head(&_enum->hlist, head);
 301         return 0;
 302
 303 sessiond_register_error:
 304         free(_enum);
 305 cache_error:
 306 socket_error:
 307 exist:
 308         return ret;
 309 }
 310
 311 static
 312 int lttng_create_enum_check(const struct lttng_type *type,
 313                 struct lttng_session *session)
 314 {
 315         switch (type->atype) {
 316         case atype_enum:
 317         {
 318                 const struct lttng_enum_desc *enum_desc;
 319                 int ret;
 320
 321                 enum_desc = type->u.basic.enumeration.desc;
 322                 ret = lttng_enum_create(enum_desc, session);
 323                 if (ret && ret != -EEXIST) {
 324                         DBG("Unable to create enum error: (%d)", ret);
 325                         return ret;
 326                 }
 327                 break;
 328         }
 329         case atype_dynamic:
 330         {
 331                 const struct lttng_event_field *tag_field_generic;
 332                 const struct lttng_enum_desc *enum_desc;
 333                 int ret;
 334
 335                 tag_field_generic = lttng_ust_dynamic_type_tag_field();
 336                 enum_desc = tag_field_generic->type.u.basic.enumeration.desc;
 337                 ret = lttng_enum_create(enum_desc, session);
 338                 if (ret && ret != -EEXIST) {
 339                         DBG("Unable to create enum error: (%d)", ret);
 340                         return ret;
 341                 }
 342                 break;
 343         }
 344         default:
 345                 /* TODO: nested types when they become supported. */
 346                 break;
 347         }
 348         return 0;
 349 }
 350
 351 static
 352 int lttng_create_all_event_enums(size_t nr_fields,
 353                 const struct lttng_event_field *event_fields,
 354                 struct lttng_session *session)
 355 {
 356         size_t i;
 357         int ret;
 358
 359         /* For each field, ensure enum is part of the session. */
 360         for (i = 0; i < nr_fields; i++) {
 361                 const struct lttng_type *type = &event_fields[i].type;
 362
 363                 ret = lttng_create_enum_check(type, session);
 364                 if (ret)
 365                         return ret;
 366         }
 367         return 0;
 368 }
 369
 370 static
 371 int lttng_create_all_ctx_enums(size_t nr_fields,
 372                 const struct lttng_ctx_field *ctx_fields,
 373                 struct lttng_session *session)
 374 {
 375         size_t i;
 376         int ret;
 377
 378         /* For each field, ensure enum is part of the session. */
 379         for (i = 0; i < nr_fields; i++) {
 380                 const struct lttng_type *type = &ctx_fields[i].event_field.type;
 381
 382                 ret = lttng_create_enum_check(type, session);
 383                 if (ret)
 384                         return ret;
 385         }
 386         return 0;
 387 }
 388
 389 /*
 390  * Ensure that a state-dump will be performed for this session at the end
 391  * of the current handle_message().
 392  */
 393 int lttng_session_statedump(struct lttng_session *session)
 394 {
 395         session->statedump_pending = 1;
 396         lttng_ust_sockinfo_session_enabled(session->owner);
 397         return 0;
 398 }
 399
 400 int lttng_session_enable(struct lttng_session *session)
 401 {
 402         int ret = 0;
 403         struct lttng_channel *chan;
 404         int notify_socket;
 405
 406         if (session->active) {
 407                 ret = -EBUSY;
 408                 goto end;
 409         }
 410
 411         notify_socket = lttng_get_notify_socket(session->owner);
 412         if (notify_socket < 0)
 413                 return notify_socket;
 414
 415         /* Set transient enabler state to "enabled" */
 416         session->tstate = 1;
 417
 418         /*
 419          * Snapshot the number of events per channel to know the type of header
 420          * we need to use.
 421          */
 422         cds_list_for_each_entry(chan, &session->chan_head, node) {
 423                 const struct lttng_ctx *ctx;
 424                 const struct lttng_ctx_field *fields = NULL;
 425                 size_t nr_fields = 0;
 426                 uint32_t chan_id;
 427
 428                 /* don't change it if session stop/restart */
 429                 if (chan->header_type)
 430                         continue;
 431                 ctx = chan->ctx;
 432                 if (ctx) {
 433                         nr_fields = ctx->nr_fields;
 434                         fields = ctx->fields;
 435                         ret = lttng_create_all_ctx_enums(nr_fields, fields,
 436                                 session);
 437                         if (ret < 0) {
 438                                 DBG("Error (%d) adding enum to session", ret);
 439                                 return ret;
 440                         }
 441                 }
 442                 ret = ustcomm_register_channel(notify_socket,
 443                         session,
 444                         session->objd,
 445                         chan->objd,
 446                         nr_fields,
 447                         fields,
 448                         &chan_id,
 449                         &chan->header_type);
 450                 if (ret) {
 451                         DBG("Error (%d) registering channel to sessiond", ret);
 452                         return ret;
 453                 }
 454                 if (chan_id != chan->id) {
 455                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 456                                 chan_id, chan->id);
 457                         return -EINVAL;
 458                 }
 459         }
 460
 461         /* We need to sync enablers with session before activation. */
 462         lttng_session_sync_enablers(session);
 463
 464         /* Set atomically the state to "active" */
 465         CMM_ACCESS_ONCE(session->active) = 1;
 466         CMM_ACCESS_ONCE(session->been_active) = 1;
 467
 468         ret = lttng_session_statedump(session);
 469         if (ret)
 470                 return ret;
 471 end:
 472         return ret;
 473 }
 474
 475 int lttng_session_disable(struct lttng_session *session)
 476 {
 477         int ret = 0;
 478
 479         if (!session->active) {
 480                 ret = -EBUSY;
 481                 goto end;
 482         }
 483         /* Set atomically the state to "inactive" */
 484         CMM_ACCESS_ONCE(session->active) = 0;
 485
 486         /* Set transient enabler state to "disabled" */
 487         session->tstate = 0;
 488         lttng_session_sync_enablers(session);
 489 end:
 490         return ret;
 491 }
 492
 493 int lttng_channel_enable(struct lttng_channel *channel)
 494 {
 495         int ret = 0;
 496
 497         if (channel->enabled) {
 498                 ret = -EBUSY;
 499                 goto end;
 500         }
 501         /* Set transient enabler state to "enabled" */
 502         channel->tstate = 1;
 503         lttng_session_sync_enablers(channel->session);
 504         /* Set atomically the state to "enabled" */
 505         CMM_ACCESS_ONCE(channel->enabled) = 1;
 506 end:
 507         return ret;
 508 }
 509
 510 int lttng_channel_disable(struct lttng_channel *channel)
 511 {
 512         int ret = 0;
 513
 514         if (!channel->enabled) {
 515                 ret = -EBUSY;
 516                 goto end;
 517         }
 518         /* Set atomically the state to "disabled" */
 519         CMM_ACCESS_ONCE(channel->enabled) = 0;
 520         /* Set transient enabler state to "enabled" */
 521         channel->tstate = 0;
 522         lttng_session_sync_enablers(channel->session);
 523 end:
 524         return ret;
 525 }
 526
 527 /*
 528  * Supports event creation while tracing session is active.
 529  */
 530 static
 531 int lttng_event_create(const struct lttng_event_desc *desc,
 532                 struct lttng_channel *chan)
 533 {
 534         const char *event_name = desc->name;
 535         struct lttng_event *event;
 536         struct lttng_session *session = chan->session;
 537         struct cds_hlist_head *head;
 538         struct cds_hlist_node *node;
 539         int ret = 0;
 540         size_t name_len = strlen(event_name);
 541         uint32_t hash;
 542         int notify_socket, loglevel;
 543         const char *uri;
 544
 545         hash = jhash(event_name, name_len, 0);
 546         head = &chan->session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 547         cds_hlist_for_each_entry(event, node, head, hlist) {
 548                 assert(event->desc);
 549                 if (!strncmp(event->desc->name, desc->name,
 550                                         LTTNG_UST_SYM_NAME_LEN - 1)
 551                                 && chan == event->chan) {
 552                         ret = -EEXIST;
 553                         goto exist;
 554                 }
 555         }
 556
 557         notify_socket = lttng_get_notify_socket(session->owner);
 558         if (notify_socket < 0) {
 559                 ret = notify_socket;
 560                 goto socket_error;
 561         }
 562
 563         ret = lttng_create_all_event_enums(desc->nr_fields, desc->fields,
 564                         session);
 565         if (ret < 0) {
 566                 DBG("Error (%d) adding enum to session", ret);
 567                 goto create_enum_error;
 568         }
 569
 570         /*
 571          * Check if loglevel match. Refuse to connect event if not.
 572          */
 573         event = zmalloc(sizeof(struct lttng_event));
 574         if (!event) {
 575                 ret = -ENOMEM;
 576                 goto cache_error;
 577         }
 578         event->chan = chan;
 579
 580         /* Event will be enabled by enabler sync. */
 581         event->enabled = 0;
 582         event->registered = 0;
 583         CDS_INIT_LIST_HEAD(&event->bytecode_runtime_head);
 584         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 585         event->desc = desc;
 586
 587         if (desc->loglevel)
 588                 loglevel = *(*event->desc->loglevel);
 589         else
 590                 loglevel = TRACE_DEFAULT;
 591         if (desc->u.ext.model_emf_uri)
 592                 uri = *(desc->u.ext.model_emf_uri);
 593         else
 594                 uri = NULL;
 595
 596         /* Fetch event ID from sessiond */
 597         ret = ustcomm_register_event(notify_socket,
 598                 session,
 599                 session->objd,
 600                 chan->objd,
 601                 event_name,
 602                 loglevel,
 603                 desc->signature,
 604                 desc->nr_fields,
 605                 desc->fields,
 606                 uri,
 607                 &event->id);
 608         if (ret < 0) {
 609                 DBG("Error (%d) registering event to sessiond", ret);
 610                 goto sessiond_register_error;
 611         }
 612
 613         /* Populate lttng_event structure before tracepoint registration. */
 614         cmm_smp_wmb();
 615         cds_list_add(&event->node, &chan->session->events_head);
 616         cds_hlist_add_head(&event->hlist, head);
 617         return 0;
 618
 619 sessiond_register_error:
 620         free(event);
 621 cache_error:
 622 create_enum_error:
 623 socket_error:
 624 exist:
 625         return ret;
 626 }
 627
 628 static
 629 int lttng_desc_match_wildcard_enabler(const struct lttng_event_desc *desc,
 630                 struct lttng_enabler *enabler)
 631 {
 632         int loglevel = 0;
 633         unsigned int has_loglevel = 0;
 634
 635         assert(enabler->type == LTTNG_ENABLER_WILDCARD);
 636         /* Compare excluding final '*' */
 637         if (strncmp(desc->name, enabler->event_param.name,
 638                         strlen(enabler->event_param.name) - 1))
 639                 return 0;
 640         if (desc->loglevel) {
 641                 loglevel = *(*desc->loglevel);
 642                 has_loglevel = 1;
 643         }
 644         if (!lttng_loglevel_match(loglevel,
 645                         has_loglevel,
 646                         enabler->event_param.loglevel_type,
 647                         enabler->event_param.loglevel))
 648                 return 0;
 649         return 1;
 650 }
 651
 652 static
 653 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 654                 struct lttng_enabler *enabler)
 655 {
 656         int loglevel = 0;
 657         unsigned int has_loglevel = 0;
 658
 659         assert(enabler->type == LTTNG_ENABLER_EVENT);
 660         if (strcmp(desc->name, enabler->event_param.name))
 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_enabler(const struct lttng_event_desc *desc,
 676                 struct lttng_enabler *enabler)
 677 {
 678         struct lttng_ust_excluder_node *excluder;
 679
 680         /* If event matches with an excluder, return 'does not match' */
 681         cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 682                 int count;
 683
 684                 for (count = 0; count < excluder->excluder.count; count++) {
 685                         int found, len;
 686                         char *excluder_name;
 687
 688                         excluder_name = (char *) (excluder->excluder.names)
 689                                         + count * LTTNG_UST_SYM_NAME_LEN;
 690                         len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 691                         if (len > 0 && excluder_name[len - 1] == '*') {
 692                                 found = !strncmp(desc->name, excluder_name,
 693                                                 len - 1);
 694                         } else {
 695                                 found = !strncmp(desc->name, excluder_name,
 696                                                 LTTNG_UST_SYM_NAME_LEN - 1);
 697                         }
 698                         if (found) {
 699                                 return 0;
 700                         }
 701                 }
 702         }
 703         switch (enabler->type) {
 704         case LTTNG_ENABLER_WILDCARD:
 705                 return lttng_desc_match_wildcard_enabler(desc, enabler);
 706         case LTTNG_ENABLER_EVENT:
 707                 return lttng_desc_match_event_enabler(desc, enabler);
 708         default:
 709                 return -EINVAL;
 710         }
 711 }
 712
 713 static
 714 int lttng_event_match_enabler(struct lttng_event *event,
 715                 struct lttng_enabler *enabler)
 716 {
 717         if (lttng_desc_match_enabler(event->desc, enabler)
 718                         && event->chan == enabler->chan)
 719                 return 1;
 720         else
 721                 return 0;
 722 }
 723
 724 static
 725 struct lttng_enabler_ref * lttng_event_enabler_ref(struct lttng_event *event,
 726                 struct lttng_enabler *enabler)
 727 {
 728         struct lttng_enabler_ref *enabler_ref;
 729
 730         cds_list_for_each_entry(enabler_ref,
 731                         &event->enablers_ref_head, node) {
 732                 if (enabler_ref->ref == enabler)
 733                         return enabler_ref;
 734         }
 735         return NULL;
 736 }
 737
 738 /*
 739  * Create struct lttng_event if it is missing and present in the list of
 740  * tracepoint probes.
 741  */
 742 static
 743 void lttng_create_event_if_missing(struct lttng_enabler *enabler)
 744 {
 745         struct lttng_session *session = enabler->chan->session;
 746         struct lttng_probe_desc *probe_desc;
 747         const struct lttng_event_desc *desc;
 748         struct lttng_event *event;
 749         int i;
 750         struct cds_list_head *probe_list;
 751
 752         probe_list = lttng_get_probe_list_head();
 753         /*
 754          * For each probe event, if we find that a probe event matches
 755          * our enabler, create an associated lttng_event if not
 756          * already present.
 757          */
 758         cds_list_for_each_entry(probe_desc, probe_list, head) {
 759                 for (i = 0; i < probe_desc->nr_events; i++) {
 760                         int found = 0, ret;
 761                         struct cds_hlist_head *head;
 762                         struct cds_hlist_node *node;
 763                         const char *event_name;
 764                         size_t name_len;
 765                         uint32_t hash;
 766
 767                         desc = probe_desc->event_desc[i];
 768                         if (!lttng_desc_match_enabler(desc, enabler))
 769                                 continue;
 770                         event_name = desc->name;
 771                         name_len = strlen(event_name);
 772
 773                         /*
 774                          * Check if already created.
 775                          */
 776                         hash = jhash(event_name, name_len, 0);
 777                         head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 778                         cds_hlist_for_each_entry(event, node, head, hlist) {
 779                                 if (event->desc == desc
 780                                                 && event->chan == enabler->chan)
 781                                         found = 1;
 782                         }
 783                         if (found)
 784                                 continue;
 785
 786                         /*
 787                          * We need to create an event for this
 788                          * event probe.
 789                          */
 790                         ret = lttng_event_create(probe_desc->event_desc[i],
 791                                         enabler->chan);
 792                         if (ret) {
 793                                 DBG("Unable to create event %s, error %d\n",
 794                                         probe_desc->event_desc[i]->name, ret);
 795                         }
 796                 }
 797         }
 798 }
 799
 800 /*
 801  * Create events associated with an enabler (if not already present),
 802  * and add backward reference from the event to the enabler.
 803  */
 804 static
 805 int lttng_enabler_ref_events(struct lttng_enabler *enabler)
 806 {
 807         struct lttng_session *session = enabler->chan->session;
 808         struct lttng_event *event;
 809
 810         /* First ensure that probe events are created for this enabler. */
 811         lttng_create_event_if_missing(enabler);
 812
 813         /* For each event matching enabler in session event list. */
 814         cds_list_for_each_entry(event, &session->events_head, node) {
 815                 struct lttng_enabler_ref *enabler_ref;
 816
 817                 if (!lttng_event_match_enabler(event, enabler))
 818                         continue;
 819
 820                 enabler_ref = lttng_event_enabler_ref(event, enabler);
 821                 if (!enabler_ref) {
 822                         /*
 823                          * If no backward ref, create it.
 824                          * Add backward ref from event to enabler.
 825                          */
 826                         enabler_ref = zmalloc(sizeof(*enabler_ref));
 827                         if (!enabler_ref)
 828                                 return -ENOMEM;
 829                         enabler_ref->ref = enabler;
 830                         cds_list_add(&enabler_ref->node,
 831                                 &event->enablers_ref_head);
 832                 }
 833
 834                 /*
 835                  * Link filter bytecodes if not linked yet.
 836                  */
 837                 lttng_enabler_event_link_bytecode(event, enabler);
 838
 839                 /* TODO: merge event context. */
 840         }
 841         return 0;
 842 }
 843
 844 /*
 845  * Called at library load: connect the probe on all enablers matching
 846  * this event.
 847  * Called with session mutex held.
 848  */
 849 int lttng_fix_pending_events(void)
 850 {
 851         struct lttng_session *session;
 852
 853         cds_list_for_each_entry(session, &sessions, node) {
 854                 lttng_session_lazy_sync_enablers(session);
 855         }
 856         return 0;
 857 }
 858
 859 /*
 860  * For each session of the owner thread, execute pending statedump.
 861  * Only dump state for the sessions owned by the caller thread, because
 862  * we don't keep ust_lock across the entire iteration.
 863  */
 864 void lttng_handle_pending_statedump(void *owner)
 865 {
 866         struct lttng_session *session;
 867
 868         /* Execute state dump */
 869         do_lttng_ust_statedump(owner);
 870
 871         /* Clear pending state dump */
 872         if (ust_lock()) {
 873                 goto end;
 874         }
 875         cds_list_for_each_entry(session, &sessions, node) {
 876                 if (session->owner != owner)
 877                         continue;
 878                 if (!session->statedump_pending)
 879                         continue;
 880                 session->statedump_pending = 0;
 881         }
 882 end:
 883         ust_unlock();
 884         return;
 885 }
 886
 887 /*
 888  * Only used internally at session destruction.
 889  */
 890 static
 891 void _lttng_event_destroy(struct lttng_event *event)
 892 {
 893         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 894
 895         cds_list_del(&event->node);
 896         lttng_destroy_context(event->ctx);
 897         lttng_free_event_filter_runtime(event);
 898         /* Free event enabler refs */
 899         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 900                         &event->enablers_ref_head, node)
 901                 free(enabler_ref);
 902         free(event);
 903 }
 904
 905 static
 906 void _lttng_enum_destroy(struct lttng_enum *_enum)
 907 {
 908         cds_list_del(&_enum->node);
 909         free(_enum);
 910 }
 911
 912 void lttng_ust_events_exit(void)
 913 {
 914         struct lttng_session *session, *tmpsession;
 915
 916         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
 917                 lttng_session_destroy(session);
 918 }
 919
 920 /*
 921  * Enabler management.
 922  */
 923 struct lttng_enabler *lttng_enabler_create(enum lttng_enabler_type type,
 924                 struct lttng_ust_event *event_param,
 925                 struct lttng_channel *chan)
 926 {
 927         struct lttng_enabler *enabler;
 928
 929         enabler = zmalloc(sizeof(*enabler));
 930         if (!enabler)
 931                 return NULL;
 932         enabler->type = type;
 933         CDS_INIT_LIST_HEAD(&enabler->filter_bytecode_head);
 934         CDS_INIT_LIST_HEAD(&enabler->excluder_head);
 935         memcpy(&enabler->event_param, event_param,
 936                 sizeof(enabler->event_param));
 937         enabler->chan = chan;
 938         /* ctx left NULL */
 939         enabler->enabled = 0;
 940         cds_list_add(&enabler->node, &enabler->chan->session->enablers_head);
 941         lttng_session_lazy_sync_enablers(enabler->chan->session);
 942         return enabler;
 943 }
 944
 945 int lttng_enabler_enable(struct lttng_enabler *enabler)
 946 {
 947         enabler->enabled = 1;
 948         lttng_session_lazy_sync_enablers(enabler->chan->session);
 949         return 0;
 950 }
 951
 952 int lttng_enabler_disable(struct lttng_enabler *enabler)
 953 {
 954         enabler->enabled = 0;
 955         lttng_session_lazy_sync_enablers(enabler->chan->session);
 956         return 0;
 957 }
 958
 959 int lttng_enabler_attach_bytecode(struct lttng_enabler *enabler,
 960                 struct lttng_ust_filter_bytecode_node *bytecode)
 961 {
 962         bytecode->enabler = enabler;
 963         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
 964         lttng_session_lazy_sync_enablers(enabler->chan->session);
 965         return 0;
 966 }
 967
 968 int lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
 969                 struct lttng_ust_excluder_node *excluder)
 970 {
 971         excluder->enabler = enabler;
 972         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
 973         lttng_session_lazy_sync_enablers(enabler->chan->session);
 974         return 0;
 975 }
 976
 977 int lttng_attach_context(struct lttng_ust_context *context_param,
 978                 union ust_args *uargs,
 979                 struct lttng_ctx **ctx, struct lttng_session *session)
 980 {
 981         /*
 982          * We cannot attach a context after trace has been started for a
 983          * session because the metadata does not allow expressing this
 984          * information outside of the original channel scope.
 985          */
 986         if (session->been_active)
 987                 return -EPERM;
 988
 989         switch (context_param->ctx) {
 990         case LTTNG_UST_CONTEXT_PTHREAD_ID:
 991                 return lttng_add_pthread_id_to_ctx(ctx);
 992         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 993         {
 994                 struct lttng_ust_perf_counter_ctx *perf_ctx_param;
 995
 996                 perf_ctx_param = &context_param->u.perf_counter;
 997                 return lttng_add_perf_counter_to_ctx(
 998                         perf_ctx_param->type,
 999                         perf_ctx_param->config,
1000                         perf_ctx_param->name,
1001                         ctx);
1002         }
1003         case LTTNG_UST_CONTEXT_VTID:
1004                 return lttng_add_vtid_to_ctx(ctx);
1005         case LTTNG_UST_CONTEXT_VPID:
1006                 return lttng_add_vpid_to_ctx(ctx);
1007         case LTTNG_UST_CONTEXT_PROCNAME:
1008                 return lttng_add_procname_to_ctx(ctx);
1009         case LTTNG_UST_CONTEXT_IP:
1010                 return lttng_add_ip_to_ctx(ctx);
1011         case LTTNG_UST_CONTEXT_CPU_ID:
1012                 return lttng_add_cpu_id_to_ctx(ctx);
1013         case LTTNG_UST_CONTEXT_APP_CONTEXT:
1014                 return lttng_ust_add_app_context_to_ctx_rcu(uargs->app_context.ctxname,
1015                         ctx);
1016         default:
1017                 return -EINVAL;
1018         }
1019 }
1020
1021 int lttng_enabler_attach_context(struct lttng_enabler *enabler,
1022                 struct lttng_ust_context *context_param)
1023 {
1024 #if 0   // disabled for now.
1025         struct lttng_session *session = enabler->chan->session;
1026         int ret;
1027
1028         ret = lttng_attach_context(context_param, &enabler->ctx,
1029                         session);
1030         if (ret)
1031                 return ret;
1032         lttng_session_lazy_sync_enablers(enabler->chan->session);
1033 #endif
1034         return -ENOSYS;
1035 }
1036
1037 static
1038 void lttng_enabler_destroy(struct lttng_enabler *enabler)
1039 {
1040         struct lttng_ust_filter_bytecode_node *filter_node, *tmp_filter_node;
1041         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
1042
1043         /* Destroy filter bytecode */
1044         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
1045                         &enabler->filter_bytecode_head, node) {
1046                 free(filter_node);
1047         }
1048
1049         /* Destroy excluders */
1050         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
1051                         &enabler->excluder_head, node) {
1052                 free(excluder_node);
1053         }
1054
1055         /* Destroy contexts */
1056         lttng_destroy_context(enabler->ctx);
1057
1058         cds_list_del(&enabler->node);
1059         free(enabler);
1060 }
1061
1062 /*
1063  * lttng_session_sync_enablers should be called just before starting a
1064  * session.
1065  */
1066 static
1067 void lttng_session_sync_enablers(struct lttng_session *session)
1068 {
1069         struct lttng_enabler *enabler;
1070         struct lttng_event *event;
1071
1072         cds_list_for_each_entry(enabler, &session->enablers_head, node)
1073                 lttng_enabler_ref_events(enabler);
1074         /*
1075          * For each event, if at least one of its enablers is enabled,
1076          * and its channel and session transient states are enabled, we
1077          * enable the event, else we disable it.
1078          */
1079         cds_list_for_each_entry(event, &session->events_head, node) {
1080                 struct lttng_enabler_ref *enabler_ref;
1081                 struct lttng_bytecode_runtime *runtime;
1082                 int enabled = 0, has_enablers_without_bytecode = 0;
1083
1084                 /* Enable events */
1085                 cds_list_for_each_entry(enabler_ref,
1086                                 &event->enablers_ref_head, node) {
1087                         if (enabler_ref->ref->enabled) {
1088                                 enabled = 1;
1089                                 break;
1090                         }
1091                 }
1092                 /*
1093                  * Enabled state is based on union of enablers, with
1094                  * intesection of session and channel transient enable
1095                  * states.
1096                  */
1097                 enabled = enabled && session->tstate && event->chan->tstate;
1098
1099                 CMM_STORE_SHARED(event->enabled, enabled);
1100                 /*
1101                  * Sync tracepoint registration with event enabled
1102                  * state.
1103                  */
1104                 if (enabled) {
1105                         if (!event->registered)
1106                                 register_event(event);
1107                 } else {
1108                         if (event->registered)
1109                                 unregister_event(event);
1110                 }
1111
1112                 /* Check if has enablers without bytecode enabled */
1113                 cds_list_for_each_entry(enabler_ref,
1114                                 &event->enablers_ref_head, node) {
1115                         if (enabler_ref->ref->enabled
1116                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
1117                                 has_enablers_without_bytecode = 1;
1118                                 break;
1119                         }
1120                 }
1121                 event->has_enablers_without_bytecode =
1122                         has_enablers_without_bytecode;
1123
1124                 /* Enable filters */
1125                 cds_list_for_each_entry(runtime,
1126                                 &event->bytecode_runtime_head, node) {
1127                         lttng_filter_sync_state(runtime);
1128                 }
1129         }
1130         __tracepoint_probe_prune_release_queue();
1131 }
1132
1133 /*
1134  * Apply enablers to session events, adding events to session if need
1135  * be. It is required after each modification applied to an active
1136  * session, and right before session "start".
1137  * "lazy" sync means we only sync if required.
1138  */
1139 static
1140 void lttng_session_lazy_sync_enablers(struct lttng_session *session)
1141 {
1142         /* We can skip if session is not active */
1143         if (!session->active)
1144                 return;
1145         lttng_session_sync_enablers(session);
1146 }
1147
1148 /*
1149  * Update all sessions with the given app context.
1150  * Called with ust lock held.
1151  * This is invoked when an application context gets loaded/unloaded. It
1152  * ensures the context callbacks are in sync with the application
1153  * context (either app context callbacks, or dummy callbacks).
1154  */
1155 void lttng_ust_context_set_session_provider(const char *name,
1156                 size_t (*get_size)(struct lttng_ctx_field *field, size_t offset),
1157                 void (*record)(struct lttng_ctx_field *field,
1158                         struct lttng_ust_lib_ring_buffer_ctx *ctx,
1159                         struct lttng_channel *chan),
1160                 void (*get_value)(struct lttng_ctx_field *field,
1161                         struct lttng_ctx_value *value))
1162 {
1163         struct lttng_session *session;
1164
1165         cds_list_for_each_entry(session, &sessions, node) {
1166                 struct lttng_channel *chan;
1167                 struct lttng_event *event;
1168                 int ret;
1169
1170                 ret = lttng_ust_context_set_provider_rcu(&session->ctx,
1171                                 name, get_size, record, get_value);
1172                 if (ret)
1173                         abort();
1174                 cds_list_for_each_entry(chan, &session->chan_head, node) {
1175                         ret = lttng_ust_context_set_provider_rcu(&chan->ctx,
1176                                         name, get_size, record, get_value);
1177                         if (ret)
1178                                 abort();
1179                 }
1180                 cds_list_for_each_entry(event, &session->events_head, node) {
1181                         ret = lttng_ust_context_set_provider_rcu(&event->ctx,
1182                                         name, get_size, record, get_value);
1183                         if (ret)
1184                                 abort();
1185                 }
1186         }
1187 }