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 "error.h"
  51 #include "compat.h"
  52 #include "lttng-ust-uuid.h"
  53
  54 #include "tracepoint-internal.h"
  55 #include "lttng-tracer.h"
  56 #include "lttng-tracer-core.h"
  57 #include "lttng-ust-baddr.h"
  58 #include "wait.h"
  59 #include "../libringbuffer/shm.h"
  60 #include "jhash.h"
  61
  62 /*
  63  * The sessions mutex is the centralized mutex across UST tracing
  64  * control and probe registration. All operations within this file are
  65  * called by the communication thread, under ust_lock protection.
  66  */
  67 static pthread_mutex_t sessions_mutex = PTHREAD_MUTEX_INITIALIZER;
  68
  69 void ust_lock(void)
  70 {
  71         pthread_mutex_lock(&sessions_mutex);
  72 }
  73
  74 void ust_unlock(void)
  75 {
  76         pthread_mutex_unlock(&sessions_mutex);
  77 }
  78
  79 static CDS_LIST_HEAD(sessions);
  80
  81 struct cds_list_head *_lttng_get_sessions(void)
  82 {
  83         return &sessions;
  84 }
  85
  86 static void _lttng_event_destroy(struct lttng_event *event);
  87
  88 static
  89 void lttng_session_lazy_sync_enablers(struct lttng_session *session);
  90 static
  91 void lttng_session_sync_enablers(struct lttng_session *session);
  92 static
  93 void lttng_enabler_destroy(struct lttng_enabler *enabler);
  94
  95 /*
  96  * Called with ust lock held.
  97  */
  98 int lttng_session_active(void)
  99 {
 100         struct lttng_session *iter;
 101
 102         cds_list_for_each_entry(iter, &sessions, node) {
 103                 if (iter->active)
 104                         return 1;
 105         }
 106         return 0;
 107 }
 108
 109 static
 110 int lttng_loglevel_match(int loglevel,
 111                 unsigned int has_loglevel,
 112                 enum lttng_ust_loglevel_type req_type,
 113                 int req_loglevel)
 114 {
 115         if (req_type == LTTNG_UST_LOGLEVEL_ALL)
 116                 return 1;
 117         if (!has_loglevel)
 118                 loglevel = TRACE_DEFAULT;
 119         switch (req_type) {
 120         case LTTNG_UST_LOGLEVEL_RANGE:
 121                 if (loglevel <= req_loglevel || req_loglevel == -1)
 122                         return 1;
 123                 else
 124                         return 0;
 125         case LTTNG_UST_LOGLEVEL_SINGLE:
 126                 if (loglevel == req_loglevel || req_loglevel == -1)
 127                         return 1;
 128                 else
 129                         return 0;
 130         case LTTNG_UST_LOGLEVEL_ALL:
 131         default:
 132                 return 1;
 133         }
 134 }
 135
 136 void synchronize_trace(void)
 137 {
 138         synchronize_rcu();
 139 }
 140
 141 struct lttng_session *lttng_session_create(void)
 142 {
 143         struct lttng_session *session;
 144         int i;
 145
 146         session = zmalloc(sizeof(struct lttng_session));
 147         if (!session)
 148                 return NULL;
 149         CDS_INIT_LIST_HEAD(&session->chan_head);
 150         CDS_INIT_LIST_HEAD(&session->events_head);
 151         CDS_INIT_LIST_HEAD(&session->enablers_head);
 152         for (i = 0; i < LTTNG_UST_EVENT_HT_SIZE; i++)
 153                 CDS_INIT_HLIST_HEAD(&session->events_ht.table[i]);
 154         cds_list_add(&session->node, &sessions);
 155         return session;
 156 }
 157
 158 /*
 159  * Only used internally at session destruction.
 160  */
 161 static
 162 void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
 163 {
 164         struct channel *chan;
 165         struct lttng_ust_shm_handle *handle;
 166
 167         cds_list_del(&lttng_chan->node);
 168         lttng_destroy_context(lttng_chan->ctx);
 169         chan = lttng_chan->chan;
 170         handle = lttng_chan->handle;
 171         /*
 172          * note: lttng_chan is private data contained within handle. It
 173          * will be freed along with the handle.
 174          */
 175         channel_destroy(chan, handle, 0);
 176 }
 177
 178 static
 179 void register_event(struct lttng_event *event)
 180 {
 181         int ret;
 182         const struct lttng_event_desc *desc;
 183
 184         assert(event->registered == 0);
 185         desc = event->desc;
 186         ret = __tracepoint_probe_register(desc->name,
 187                         desc->probe_callback,
 188                         event, desc->signature);
 189         WARN_ON_ONCE(ret);
 190         if (!ret)
 191                 event->registered = 1;
 192 }
 193
 194 static
 195 void unregister_event(struct lttng_event *event)
 196 {
 197         int ret;
 198         const struct lttng_event_desc *desc;
 199
 200         assert(event->registered == 1);
 201         desc = event->desc;
 202         ret = __tracepoint_probe_unregister(desc->name,
 203                         desc->probe_callback,
 204                         event);
 205         WARN_ON_ONCE(ret);
 206         if (!ret)
 207                 event->registered = 0;
 208 }
 209
 210 /*
 211  * Only used internally at session destruction.
 212  */
 213 static
 214 void _lttng_event_unregister(struct lttng_event *event)
 215 {
 216         if (event->registered)
 217                 unregister_event(event);
 218 }
 219
 220 void lttng_session_destroy(struct lttng_session *session)
 221 {
 222         struct lttng_channel *chan, *tmpchan;
 223         struct lttng_event *event, *tmpevent;
 224         struct lttng_enabler *enabler, *tmpenabler;
 225
 226         CMM_ACCESS_ONCE(session->active) = 0;
 227         cds_list_for_each_entry(event, &session->events_head, node) {
 228                 _lttng_event_unregister(event);
 229         }
 230         synchronize_trace();    /* Wait for in-flight events to complete */
 231         cds_list_for_each_entry_safe(enabler, tmpenabler,
 232                         &session->enablers_head, node)
 233                 lttng_enabler_destroy(enabler);
 234         cds_list_for_each_entry_safe(event, tmpevent,
 235                         &session->events_head, node)
 236                 _lttng_event_destroy(event);
 237         cds_list_for_each_entry_safe(chan, tmpchan, &session->chan_head, node)
 238                 _lttng_channel_unmap(chan);
 239         cds_list_del(&session->node);
 240         free(session);
 241 }
 242
 243 int lttng_session_enable(struct lttng_session *session)
 244 {
 245         int ret = 0;
 246         struct lttng_channel *chan;
 247         int notify_socket;
 248
 249         if (session->active) {
 250                 ret = -EBUSY;
 251                 goto end;
 252         }
 253
 254         notify_socket = lttng_get_notify_socket(session->owner);
 255         if (notify_socket < 0)
 256                 return notify_socket;
 257
 258         /* Set transient enabler state to "enabled" */
 259         session->tstate = 1;
 260         /* We need to sync enablers with session before activation. */
 261         lttng_session_sync_enablers(session);
 262
 263         /*
 264          * Snapshot the number of events per channel to know the type of header
 265          * we need to use.
 266          */
 267         cds_list_for_each_entry(chan, &session->chan_head, node) {
 268                 const struct lttng_ctx *ctx;
 269                 const struct lttng_ctx_field *fields = NULL;
 270                 size_t nr_fields = 0;
 271                 uint32_t chan_id;
 272
 273                 /* don't change it if session stop/restart */
 274                 if (chan->header_type)
 275                         continue;
 276                 ctx = chan->ctx;
 277                 if (ctx) {
 278                         nr_fields = ctx->nr_fields;
 279                         fields = ctx->fields;
 280                 }
 281                 ret = ustcomm_register_channel(notify_socket,
 282                         session->objd,
 283                         chan->objd,
 284                         nr_fields,
 285                         fields,
 286                         &chan_id,
 287                         &chan->header_type);
 288                 if (ret) {
 289                         DBG("Error (%d) registering channel to sessiond", ret);
 290                         return ret;
 291                 }
 292                 if (chan_id != chan->id) {
 293                         DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
 294                                 chan_id, chan->id);
 295                         return -EINVAL;
 296                 }
 297         }
 298
 299         /* Set atomically the state to "active" */
 300         CMM_ACCESS_ONCE(session->active) = 1;
 301         CMM_ACCESS_ONCE(session->been_active) = 1;
 302
 303         session->statedump_pending = 1;
 304         lttng_ust_sockinfo_session_enabled(session->owner);
 305 end:
 306         return ret;
 307 }
 308
 309 int lttng_session_disable(struct lttng_session *session)
 310 {
 311         int ret = 0;
 312
 313         if (!session->active) {
 314                 ret = -EBUSY;
 315                 goto end;
 316         }
 317         /* Set atomically the state to "inactive" */
 318         CMM_ACCESS_ONCE(session->active) = 0;
 319
 320         /* Set transient enabler state to "disabled" */
 321         session->tstate = 0;
 322         lttng_session_sync_enablers(session);
 323 end:
 324         return ret;
 325 }
 326
 327 int lttng_channel_enable(struct lttng_channel *channel)
 328 {
 329         int ret = 0;
 330
 331         if (channel->enabled) {
 332                 ret = -EBUSY;
 333                 goto end;
 334         }
 335         /* Set transient enabler state to "enabled" */
 336         channel->tstate = 1;
 337         lttng_session_sync_enablers(channel->session);
 338         /* Set atomically the state to "enabled" */
 339         CMM_ACCESS_ONCE(channel->enabled) = 1;
 340 end:
 341         return ret;
 342 }
 343
 344 int lttng_channel_disable(struct lttng_channel *channel)
 345 {
 346         int ret = 0;
 347
 348         if (!channel->enabled) {
 349                 ret = -EBUSY;
 350                 goto end;
 351         }
 352         /* Set atomically the state to "disabled" */
 353         CMM_ACCESS_ONCE(channel->enabled) = 0;
 354         /* Set transient enabler state to "enabled" */
 355         channel->tstate = 0;
 356         lttng_session_sync_enablers(channel->session);
 357 end:
 358         return ret;
 359 }
 360
 361 /*
 362  * Supports event creation while tracing session is active.
 363  */
 364 static
 365 int lttng_event_create(const struct lttng_event_desc *desc,
 366                 struct lttng_channel *chan)
 367 {
 368         const char *event_name = desc->name;
 369         struct lttng_event *event;
 370         struct lttng_session *session = chan->session;
 371         struct cds_hlist_head *head;
 372         struct cds_hlist_node *node;
 373         int ret = 0;
 374         size_t name_len = strlen(event_name);
 375         uint32_t hash;
 376         int notify_socket, loglevel;
 377         const char *uri;
 378
 379         hash = jhash(event_name, name_len, 0);
 380         head = &chan->session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 381         cds_hlist_for_each_entry(event, node, head, hlist) {
 382                 assert(event->desc);
 383                 if (!strncmp(event->desc->name, desc->name,
 384                                         LTTNG_UST_SYM_NAME_LEN - 1)
 385                                 && chan == event->chan) {
 386                         ret = -EEXIST;
 387                         goto exist;
 388                 }
 389         }
 390
 391         notify_socket = lttng_get_notify_socket(session->owner);
 392         if (notify_socket < 0) {
 393                 ret = notify_socket;
 394                 goto socket_error;
 395         }
 396
 397         /*
 398          * Check if loglevel match. Refuse to connect event if not.
 399          */
 400         event = zmalloc(sizeof(struct lttng_event));
 401         if (!event) {
 402                 ret = -ENOMEM;
 403                 goto cache_error;
 404         }
 405         event->chan = chan;
 406
 407         /* Event will be enabled by enabler sync. */
 408         event->enabled = 0;
 409         event->registered = 0;
 410         CDS_INIT_LIST_HEAD(&event->bytecode_runtime_head);
 411         CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
 412         event->desc = desc;
 413
 414         if (desc->loglevel)
 415                 loglevel = *(*event->desc->loglevel);
 416         else
 417                 loglevel = TRACE_DEFAULT;
 418         if (desc->u.ext.model_emf_uri)
 419                 uri = *(desc->u.ext.model_emf_uri);
 420         else
 421                 uri = NULL;
 422
 423         /* Fetch event ID from sessiond */
 424         ret = ustcomm_register_event(notify_socket,
 425                 session->objd,
 426                 chan->objd,
 427                 event_name,
 428                 loglevel,
 429                 desc->signature,
 430                 desc->nr_fields,
 431                 desc->fields,
 432                 uri,
 433                 &event->id);
 434         if (ret < 0) {
 435                 DBG("Error (%d) registering event to sessiond", ret);
 436                 goto sessiond_register_error;
 437         }
 438
 439         /* Populate lttng_event structure before tracepoint registration. */
 440         cmm_smp_wmb();
 441         cds_list_add(&event->node, &chan->session->events_head);
 442         cds_hlist_add_head(&event->hlist, head);
 443         return 0;
 444
 445 sessiond_register_error:
 446         free(event);
 447 cache_error:
 448 socket_error:
 449 exist:
 450         return ret;
 451 }
 452
 453 static
 454 int lttng_desc_match_wildcard_enabler(const struct lttng_event_desc *desc,
 455                 struct lttng_enabler *enabler)
 456 {
 457         int loglevel = 0;
 458         unsigned int has_loglevel = 0;
 459
 460         assert(enabler->type == LTTNG_ENABLER_WILDCARD);
 461         /* Compare excluding final '*' */
 462         if (strncmp(desc->name, enabler->event_param.name,
 463                         strlen(enabler->event_param.name) - 1))
 464                 return 0;
 465         if (desc->loglevel) {
 466                 loglevel = *(*desc->loglevel);
 467                 has_loglevel = 1;
 468         }
 469         if (!lttng_loglevel_match(loglevel,
 470                         has_loglevel,
 471                         enabler->event_param.loglevel_type,
 472                         enabler->event_param.loglevel))
 473                 return 0;
 474         return 1;
 475 }
 476
 477 static
 478 int lttng_desc_match_event_enabler(const struct lttng_event_desc *desc,
 479                 struct lttng_enabler *enabler)
 480 {
 481         int loglevel = 0;
 482         unsigned int has_loglevel = 0;
 483
 484         assert(enabler->type == LTTNG_ENABLER_EVENT);
 485         if (strcmp(desc->name, enabler->event_param.name))
 486                 return 0;
 487         if (desc->loglevel) {
 488                 loglevel = *(*desc->loglevel);
 489                 has_loglevel = 1;
 490         }
 491         if (!lttng_loglevel_match(loglevel,
 492                         has_loglevel,
 493                         enabler->event_param.loglevel_type,
 494                         enabler->event_param.loglevel))
 495                 return 0;
 496         return 1;
 497 }
 498
 499 static
 500 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
 501                 struct lttng_enabler *enabler)
 502 {
 503         struct lttng_ust_excluder_node *excluder;
 504
 505         /* If event matches with an excluder, return 'does not match' */
 506         cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
 507                 int count;
 508
 509                 for (count = 0; count < excluder->excluder.count; count++) {
 510                         int found, len;
 511                         char *excluder_name;
 512
 513                         excluder_name = (char *) (excluder->excluder.names)
 514                                         + count * LTTNG_UST_SYM_NAME_LEN;
 515                         len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
 516                         if (len > 0 && excluder_name[len - 1] == '*') {
 517                                 found = !strncmp(desc->name, excluder_name,
 518                                                 len - 1);
 519                         } else {
 520                                 found = !strncmp(desc->name, excluder_name,
 521                                                 LTTNG_UST_SYM_NAME_LEN - 1);
 522                         }
 523                         if (found) {
 524                                 return 0;
 525                         }
 526                 }
 527         }
 528         switch (enabler->type) {
 529         case LTTNG_ENABLER_WILDCARD:
 530                 return lttng_desc_match_wildcard_enabler(desc, enabler);
 531         case LTTNG_ENABLER_EVENT:
 532                 return lttng_desc_match_event_enabler(desc, enabler);
 533         default:
 534                 return -EINVAL;
 535         }
 536 }
 537
 538 static
 539 int lttng_event_match_enabler(struct lttng_event *event,
 540                 struct lttng_enabler *enabler)
 541 {
 542         if (lttng_desc_match_enabler(event->desc, enabler)
 543                         && event->chan == enabler->chan)
 544                 return 1;
 545         else
 546                 return 0;
 547 }
 548
 549 static
 550 struct lttng_enabler_ref * lttng_event_enabler_ref(struct lttng_event *event,
 551                 struct lttng_enabler *enabler)
 552 {
 553         struct lttng_enabler_ref *enabler_ref;
 554
 555         cds_list_for_each_entry(enabler_ref,
 556                         &event->enablers_ref_head, node) {
 557                 if (enabler_ref->ref == enabler)
 558                         return enabler_ref;
 559         }
 560         return NULL;
 561 }
 562
 563 /*
 564  * Create struct lttng_event if it is missing and present in the list of
 565  * tracepoint probes.
 566  */
 567 static
 568 void lttng_create_event_if_missing(struct lttng_enabler *enabler)
 569 {
 570         struct lttng_session *session = enabler->chan->session;
 571         struct lttng_probe_desc *probe_desc;
 572         const struct lttng_event_desc *desc;
 573         struct lttng_event *event;
 574         int i;
 575         struct cds_list_head *probe_list;
 576
 577         probe_list = lttng_get_probe_list_head();
 578         /*
 579          * For each probe event, if we find that a probe event matches
 580          * our enabler, create an associated lttng_event if not
 581          * already present.
 582          */
 583         cds_list_for_each_entry(probe_desc, probe_list, head) {
 584                 for (i = 0; i < probe_desc->nr_events; i++) {
 585                         int found = 0, ret;
 586                         struct cds_hlist_head *head;
 587                         struct cds_hlist_node *node;
 588                         const char *event_name;
 589                         size_t name_len;
 590                         uint32_t hash;
 591
 592                         desc = probe_desc->event_desc[i];
 593                         if (!lttng_desc_match_enabler(desc, enabler))
 594                                 continue;
 595                         event_name = desc->name;
 596                         name_len = strlen(event_name);
 597
 598                         /*
 599                          * Check if already created.
 600                          */
 601                         hash = jhash(event_name, name_len, 0);
 602                         head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
 603                         cds_hlist_for_each_entry(event, node, head, hlist) {
 604                                 if (event->desc == desc
 605                                                 && event->chan == enabler->chan)
 606                                         found = 1;
 607                         }
 608                         if (found)
 609                                 continue;
 610
 611                         /*
 612                          * We need to create an event for this
 613                          * event probe.
 614                          */
 615                         ret = lttng_event_create(probe_desc->event_desc[i],
 616                                         enabler->chan);
 617                         if (ret) {
 618                                 DBG("Unable to create event %s, error %d\n",
 619                                         probe_desc->event_desc[i]->name, ret);
 620                         }
 621                 }
 622         }
 623 }
 624
 625 /*
 626  * Create events associated with an enabler (if not already present),
 627  * and add backward reference from the event to the enabler.
 628  */
 629 static
 630 int lttng_enabler_ref_events(struct lttng_enabler *enabler)
 631 {
 632         struct lttng_session *session = enabler->chan->session;
 633         struct lttng_event *event;
 634
 635         /* First ensure that probe events are created for this enabler. */
 636         lttng_create_event_if_missing(enabler);
 637
 638         /* For each event matching enabler in session event list. */
 639         cds_list_for_each_entry(event, &session->events_head, node) {
 640                 struct lttng_enabler_ref *enabler_ref;
 641
 642                 if (!lttng_event_match_enabler(event, enabler))
 643                         continue;
 644
 645                 enabler_ref = lttng_event_enabler_ref(event, enabler);
 646                 if (!enabler_ref) {
 647                         /*
 648                          * If no backward ref, create it.
 649                          * Add backward ref from event to enabler.
 650                          */
 651                         enabler_ref = zmalloc(sizeof(*enabler_ref));
 652                         if (!enabler_ref)
 653                                 return -ENOMEM;
 654                         enabler_ref->ref = enabler;
 655                         cds_list_add(&enabler_ref->node,
 656                                 &event->enablers_ref_head);
 657                 }
 658
 659                 /*
 660                  * Link filter bytecodes if not linked yet.
 661                  */
 662                 lttng_enabler_event_link_bytecode(event, enabler);
 663
 664                 /* TODO: merge event context. */
 665         }
 666         return 0;
 667 }
 668
 669 /*
 670  * Called at library load: connect the probe on all enablers matching
 671  * this event.
 672  * Called with session mutex held.
 673  */
 674 int lttng_fix_pending_events(void)
 675 {
 676         struct lttng_session *session;
 677
 678         cds_list_for_each_entry(session, &sessions, node) {
 679                 lttng_session_lazy_sync_enablers(session);
 680         }
 681         return 0;
 682 }
 683
 684 /*
 685  * For each session of the owner thread, execute pending statedump.
 686  * Only dump state for the sessions owned by the caller thread, because
 687  * we don't keep ust_lock across the entire iteration.
 688  */
 689 int lttng_handle_pending_statedump(void *owner)
 690 {
 691         struct lttng_session *session;
 692
 693         /* Execute state dump */
 694         lttng_ust_baddr_statedump(owner);
 695
 696         /* Clear pending state dump */
 697         ust_lock();
 698         cds_list_for_each_entry(session, &sessions, node) {
 699                 if (session->owner != owner)
 700                         continue;
 701                 if (!session->statedump_pending)
 702                         continue;
 703                 session->statedump_pending = 0;
 704         }
 705         ust_unlock();
 706         return 0;
 707 }
 708
 709 /*
 710  * Only used internally at session destruction.
 711  */
 712 static
 713 void _lttng_event_destroy(struct lttng_event *event)
 714 {
 715         struct lttng_enabler_ref *enabler_ref, *tmp_enabler_ref;
 716
 717         cds_list_del(&event->node);
 718         lttng_destroy_context(event->ctx);
 719         lttng_free_event_filter_runtime(event);
 720         /* Free event enabler refs */
 721         cds_list_for_each_entry_safe(enabler_ref, tmp_enabler_ref,
 722                         &event->enablers_ref_head, node)
 723                 free(enabler_ref);
 724         free(event);
 725 }
 726
 727 void lttng_ust_events_exit(void)
 728 {
 729         struct lttng_session *session, *tmpsession;
 730
 731         cds_list_for_each_entry_safe(session, tmpsession, &sessions, node)
 732                 lttng_session_destroy(session);
 733 }
 734
 735 /*
 736  * Enabler management.
 737  */
 738 struct lttng_enabler *lttng_enabler_create(enum lttng_enabler_type type,
 739                 struct lttng_ust_event *event_param,
 740                 struct lttng_channel *chan)
 741 {
 742         struct lttng_enabler *enabler;
 743
 744         enabler = zmalloc(sizeof(*enabler));
 745         if (!enabler)
 746                 return NULL;
 747         enabler->type = type;
 748         CDS_INIT_LIST_HEAD(&enabler->filter_bytecode_head);
 749         CDS_INIT_LIST_HEAD(&enabler->excluder_head);
 750         memcpy(&enabler->event_param, event_param,
 751                 sizeof(enabler->event_param));
 752         enabler->chan = chan;
 753         /* ctx left NULL */
 754         enabler->enabled = 1;
 755         cds_list_add(&enabler->node, &enabler->chan->session->enablers_head);
 756         lttng_session_lazy_sync_enablers(enabler->chan->session);
 757         return enabler;
 758 }
 759
 760 int lttng_enabler_enable(struct lttng_enabler *enabler)
 761 {
 762         enabler->enabled = 1;
 763         lttng_session_lazy_sync_enablers(enabler->chan->session);
 764         return 0;
 765 }
 766
 767 int lttng_enabler_disable(struct lttng_enabler *enabler)
 768 {
 769         enabler->enabled = 0;
 770         lttng_session_lazy_sync_enablers(enabler->chan->session);
 771         return 0;
 772 }
 773
 774 int lttng_enabler_attach_bytecode(struct lttng_enabler *enabler,
 775                 struct lttng_ust_filter_bytecode_node *bytecode)
 776 {
 777         bytecode->enabler = enabler;
 778         cds_list_add_tail(&bytecode->node, &enabler->filter_bytecode_head);
 779         lttng_session_lazy_sync_enablers(enabler->chan->session);
 780         return 0;
 781 }
 782
 783 int lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
 784                 struct lttng_ust_excluder_node *excluder)
 785 {
 786         excluder->enabler = enabler;
 787         cds_list_add_tail(&excluder->node, &enabler->excluder_head);
 788         lttng_session_lazy_sync_enablers(enabler->chan->session);
 789         return 0;
 790 }
 791
 792 int lttng_attach_context(struct lttng_ust_context *context_param,
 793                 struct lttng_ctx **ctx, struct lttng_session *session)
 794 {
 795         /*
 796          * We cannot attach a context after trace has been started for a
 797          * session because the metadata does not allow expressing this
 798          * information outside of the original channel scope.
 799          */
 800         if (session->been_active)
 801                 return -EPERM;
 802
 803         switch (context_param->ctx) {
 804         case LTTNG_UST_CONTEXT_PTHREAD_ID:
 805                 return lttng_add_pthread_id_to_ctx(ctx);
 806         case LTTNG_UST_CONTEXT_VTID:
 807                 return lttng_add_vtid_to_ctx(ctx);
 808         case LTTNG_UST_CONTEXT_VPID:
 809                 return lttng_add_vpid_to_ctx(ctx);
 810         case LTTNG_UST_CONTEXT_PROCNAME:
 811                 return lttng_add_procname_to_ctx(ctx);
 812         case LTTNG_UST_CONTEXT_IP:
 813                 return lttng_add_ip_to_ctx(ctx);
 814         default:
 815                 return -EINVAL;
 816         }
 817 }
 818
 819 int lttng_enabler_attach_context(struct lttng_enabler *enabler,
 820                 struct lttng_ust_context *context_param)
 821 {
 822 #if 0   // disabled for now.
 823         struct lttng_session *session = enabler->chan->session;
 824         int ret;
 825
 826         ret = lttng_attach_context(context_param, &enabler->ctx,
 827                         session);
 828         if (ret)
 829                 return ret;
 830         lttng_session_lazy_sync_enablers(enabler->chan->session);
 831 #endif
 832         return -ENOSYS;
 833 }
 834
 835 static
 836 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 837 {
 838         struct lttng_ust_filter_bytecode_node *filter_node, *tmp_filter_node;
 839         struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 840
 841         /* Destroy filter bytecode */
 842         cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
 843                         &enabler->filter_bytecode_head, node) {
 844                 free(filter_node);
 845         }
 846
 847         /* Destroy excluders */
 848         cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
 849                         &enabler->excluder_head, node) {
 850                 free(excluder_node);
 851         }
 852
 853         /* Destroy contexts */
 854         lttng_destroy_context(enabler->ctx);
 855
 856         cds_list_del(&enabler->node);
 857         free(enabler);
 858 }
 859
 860 /*
 861  * lttng_session_sync_enablers should be called just before starting a
 862  * session.
 863  */
 864 static
 865 void lttng_session_sync_enablers(struct lttng_session *session)
 866 {
 867         struct lttng_enabler *enabler;
 868         struct lttng_event *event;
 869
 870         cds_list_for_each_entry(enabler, &session->enablers_head, node)
 871                 lttng_enabler_ref_events(enabler);
 872         /*
 873          * For each event, if at least one of its enablers is enabled,
 874          * and its channel and session transient states are enabled, we
 875          * enable the event, else we disable it.
 876          */
 877         cds_list_for_each_entry(event, &session->events_head, node) {
 878                 struct lttng_enabler_ref *enabler_ref;
 879                 struct lttng_bytecode_runtime *runtime;
 880                 int enabled = 0, has_enablers_without_bytecode = 0;
 881
 882                 /* Enable events */
 883                 cds_list_for_each_entry(enabler_ref,
 884                                 &event->enablers_ref_head, node) {
 885                         if (enabler_ref->ref->enabled) {
 886                                 enabled = 1;
 887                                 break;
 888                         }
 889                 }
 890                 /*
 891                  * Enabled state is based on union of enablers, with
 892                  * intesection of session and channel transient enable
 893                  * states.
 894                  */
 895                 enabled = enabled && session->tstate && event->chan->tstate;
 896
 897                 CMM_STORE_SHARED(event->enabled, enabled);
 898                 /*
 899                  * Sync tracepoint registration with event enabled
 900                  * state.
 901                  */
 902                 if (enabled) {
 903                         if (!event->registered)
 904                                 register_event(event);
 905                 } else {
 906                         if (event->registered)
 907                                 unregister_event(event);
 908                 }
 909
 910                 /* Check if has enablers without bytecode enabled */
 911                 cds_list_for_each_entry(enabler_ref,
 912                                 &event->enablers_ref_head, node) {
 913                         if (enabler_ref->ref->enabled
 914                                         && cds_list_empty(&enabler_ref->ref->filter_bytecode_head)) {
 915                                 has_enablers_without_bytecode = 1;
 916                                 break;
 917                         }
 918                 }
 919                 event->has_enablers_without_bytecode =
 920                         has_enablers_without_bytecode;
 921
 922                 /* Enable filters */
 923                 cds_list_for_each_entry(runtime,
 924                                 &event->bytecode_runtime_head, node) {
 925                         lttng_filter_sync_state(runtime);
 926                 }
 927         }
 928 }
 929
 930 /*
 931  * Apply enablers to session events, adding events to session if need
 932  * be. It is required after each modification applied to an active
 933  * session, and right before session "start".
 934  * "lazy" sync means we only sync if required.
 935  */
 936 static
 937 void lttng_session_lazy_sync_enablers(struct lttng_session *session)
 938 {
 939         /* We can skip if session is not active */
 940         if (!session->active)
 941                 return;
 942         lttng_session_sync_enablers(session);
 943 }