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