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