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