src/bin/lttng-sessiond/trace-ust.c

   1 /*
   2  * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0-only
   6  *
   7  */
   8
   9 #define _LGPL_SOURCE
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <unistd.h>
  14 #include <inttypes.h>
  15
  16 #include <common/common.h>
  17 #include <common/defaults.h>
  18 #include <common/trace-chunk.h>
  19 #include <common/utils.h>
  20
  21 #include "buffer-registry.h"
  22 #include "trace-ust.h"
  23 #include "utils.h"
  24 #include "ust-app.h"
  25 #include "agent.h"
  26
  27 /*
  28  * Match function for the events hash table lookup.
  29  *
  30  * Matches by name only. Used by the disable command.
  31  */
  32 int trace_ust_ht_match_event_by_name(struct cds_lfht_node *node,
  33                 const void *_key)
  34 {
  35         struct ltt_ust_event *event;
  36         const char *name;
  37
  38         assert(node);
  39         assert(_key);
  40
  41         event = caa_container_of(node, struct ltt_ust_event, node.node);
  42         name = _key;
  43
  44         /* Event name */
  45         if (strncmp(event->attr.name, name, sizeof(event->attr.name)) != 0) {
  46                 goto no_match;
  47         }
  48
  49         /* Match */
  50         return 1;
  51
  52 no_match:
  53         return 0;
  54 }
  55
  56 /*
  57  * Match function for the hash table lookup.
  58  *
  59  * It matches an ust event based on three attributes which are the event name,
  60  * the filter bytecode and the loglevel.
  61  */
  62 int trace_ust_ht_match_event(struct cds_lfht_node *node, const void *_key)
  63 {
  64         struct ltt_ust_event *event;
  65         const struct ltt_ust_ht_key *key;
  66         int ev_loglevel_value;
  67         int ll_match;
  68
  69         assert(node);
  70         assert(_key);
  71
  72         event = caa_container_of(node, struct ltt_ust_event, node.node);
  73         key = _key;
  74         ev_loglevel_value = event->attr.loglevel;
  75
  76         /* Match the 4 elements of the key: name, filter, loglevel, exclusions. */
  77
  78         /* Event name */
  79         if (strncmp(event->attr.name, key->name, sizeof(event->attr.name)) != 0) {
  80                 goto no_match;
  81         }
  82
  83         /* Event loglevel value and type. */
  84         ll_match = loglevels_match(event->attr.loglevel_type,
  85                 ev_loglevel_value, key->loglevel_type,
  86                 key->loglevel_value, LTTNG_UST_LOGLEVEL_ALL);
  87
  88         if (!ll_match) {
  89                 goto no_match;
  90         }
  91
  92         /* Only one of the filters is NULL, fail. */
  93         if ((key->filter && !event->filter) || (!key->filter && event->filter)) {
  94                 goto no_match;
  95         }
  96
  97         if (key->filter && event->filter) {
  98                 /* Both filters exists, check length followed by the bytecode. */
  99                 if (event->filter->len != key->filter->len ||
 100                                 memcmp(event->filter->data, key->filter->data,
 101                                         event->filter->len) != 0) {
 102                         goto no_match;
 103                 }
 104         }
 105
 106         /* If only one of the exclusions is NULL, fail. */
 107         if ((key->exclusion && !event->exclusion) || (!key->exclusion && event->exclusion)) {
 108                 goto no_match;
 109         }
 110
 111         if (key->exclusion && event->exclusion) {
 112                 size_t i;
 113
 114                 /* Check exclusion counts first. */
 115                 if (event->exclusion->count != key->exclusion->count) {
 116                         goto no_match;
 117                 }
 118
 119                 /* Compare names individually. */
 120                 for (i = 0; i < event->exclusion->count; ++i) {
 121                         size_t j;
 122                         bool found = false;
 123                         const char *name_ev =
 124                                 LTTNG_EVENT_EXCLUSION_NAME_AT(
 125                                         event->exclusion, i);
 126
 127                         /*
 128                          * Compare this exclusion name to all the key's
 129                          * exclusion names.
 130                          */
 131                         for (j = 0; j < key->exclusion->count; ++j) {
 132                                 const char *name_key =
 133                                         LTTNG_EVENT_EXCLUSION_NAME_AT(
 134                                                 key->exclusion, j);
 135
 136                                 if (!strncmp(name_ev, name_key,
 137                                                 LTTNG_SYMBOL_NAME_LEN)) {
 138                                         /* Names match! */
 139                                         found = true;
 140                                         break;
 141                                 }
 142                         }
 143
 144                         /*
 145                          * If the current exclusion name was not found amongst
 146                          * the key's exclusion names, then there's no match.
 147                          */
 148                         if (!found) {
 149                                 goto no_match;
 150                         }
 151                 }
 152         }
 153         /* Match. */
 154         return 1;
 155
 156 no_match:
 157         return 0;
 158 }
 159
 160 /*
 161  * Find the channel in the hashtable and return channel pointer. RCU read side
 162  * lock MUST be acquired before calling this.
 163  */
 164 struct ltt_ust_channel *trace_ust_find_channel_by_name(struct lttng_ht *ht,
 165                 const char *name)
 166 {
 167         struct lttng_ht_node_str *node;
 168         struct lttng_ht_iter iter;
 169
 170         /*
 171          * If we receive an empty string for channel name, it means the
 172          * default channel name is requested.
 173          */
 174         if (name[0] == '\0')
 175                 name = DEFAULT_CHANNEL_NAME;
 176
 177         lttng_ht_lookup(ht, (void *)name, &iter);
 178         node = lttng_ht_iter_get_node_str(&iter);
 179         if (node == NULL) {
 180                 goto error;
 181         }
 182
 183         DBG2("Trace UST channel %s found by name", name);
 184
 185         return caa_container_of(node, struct ltt_ust_channel, node);
 186
 187 error:
 188         DBG2("Trace UST channel %s not found by name", name);
 189         return NULL;
 190 }
 191
 192 /*
 193  * Find the event in the hashtable and return event pointer. RCU read side lock
 194  * MUST be acquired before calling this.
 195  */
 196 struct ltt_ust_event *trace_ust_find_event(struct lttng_ht *ht,
 197                 char *name, struct lttng_filter_bytecode *filter,
 198                 enum lttng_ust_loglevel_type loglevel_type, int loglevel_value,
 199                 struct lttng_event_exclusion *exclusion)
 200 {
 201         struct lttng_ht_node_str *node;
 202         struct lttng_ht_iter iter;
 203         struct ltt_ust_ht_key key;
 204
 205         assert(name);
 206         assert(ht);
 207
 208         key.name = name;
 209         key.filter = filter;
 210         key.loglevel_type = loglevel_type;
 211         key.loglevel_value = loglevel_value;
 212         key.exclusion = exclusion;
 213
 214         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 215                         trace_ust_ht_match_event, &key, &iter.iter);
 216         node = lttng_ht_iter_get_node_str(&iter);
 217         if (node == NULL) {
 218                 goto error;
 219         }
 220
 221         DBG2("Trace UST event %s found", key.name);
 222
 223         return caa_container_of(node, struct ltt_ust_event, node);
 224
 225 error:
 226         DBG2("Trace UST event %s NOT found", key.name);
 227         return NULL;
 228 }
 229
 230 /*
 231  * Lookup an agent in the session agents hash table by domain type and return
 232  * the object if found else NULL.
 233  *
 234  * RCU read side lock must be acquired before calling and only released
 235  * once the agent is no longer in scope or being used.
 236  */
 237 struct agent *trace_ust_find_agent(struct ltt_ust_session *session,
 238                 enum lttng_domain_type domain_type)
 239 {
 240         struct agent *agt = NULL;
 241         struct lttng_ht_node_u64 *node;
 242         struct lttng_ht_iter iter;
 243         uint64_t key;
 244
 245         assert(session);
 246
 247         DBG3("Trace ust agent lookup for domain %d", domain_type);
 248
 249         key = domain_type;
 250
 251         lttng_ht_lookup(session->agents, &key, &iter);
 252         node = lttng_ht_iter_get_node_u64(&iter);
 253         if (!node) {
 254                 goto end;
 255         }
 256         agt = caa_container_of(node, struct agent, node);
 257
 258 end:
 259         return agt;
 260 }
 261
 262 /*
 263  * Allocate and initialize a ust session data structure.
 264  *
 265  * Return pointer to structure or NULL.
 266  */
 267 struct ltt_ust_session *trace_ust_create_session(uint64_t session_id)
 268 {
 269         struct ltt_ust_session *lus;
 270
 271         /* Allocate a new ltt ust session */
 272         lus = zmalloc(sizeof(struct ltt_ust_session));
 273         if (lus == NULL) {
 274                 PERROR("create ust session zmalloc");
 275                 goto error_alloc;
 276         }
 277
 278         /* Init data structure */
 279         lus->id = session_id;
 280         lus->active = 0;
 281
 282         /* Set default metadata channel attribute. */
 283         lus->metadata_attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 284         lus->metadata_attr.subbuf_size = default_get_metadata_subbuf_size();
 285         lus->metadata_attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 286         lus->metadata_attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
 287         lus->metadata_attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;
 288         lus->metadata_attr.output = LTTNG_UST_MMAP;
 289
 290         /*
 291          * Default buffer type. This can be changed through an enable channel
 292          * requesting a different type. Note that this can only be changed once
 293          * during the session lifetime which is at the first enable channel and
 294          * only before start. The flag buffer_type_changed indicates the status.
 295          */
 296         lus->buffer_type = LTTNG_BUFFER_PER_UID;
 297         /* Once set to 1, the buffer_type is immutable for the session. */
 298         lus->buffer_type_changed = 0;
 299         /* Init it in case it get used after allocation. */
 300         CDS_INIT_LIST_HEAD(&lus->buffer_reg_uid_list);
 301
 302         /* Alloc UST global domain channels' HT */
 303         lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 304         /* Alloc agent hash table. */
 305         lus->agents = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 306
 307         lus->tracker_vpid = process_attr_tracker_create();
 308         if (!lus->tracker_vpid) {
 309                 goto error;
 310         }
 311         lus->tracker_vuid = process_attr_tracker_create();
 312         if (!lus->tracker_vuid) {
 313                 goto error;
 314         }
 315         lus->tracker_vgid = process_attr_tracker_create();
 316         if (!lus->tracker_vgid) {
 317                 goto error;
 318         }
 319         lus->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 320         if (lus->consumer == NULL) {
 321                 goto error;
 322         }
 323
 324         DBG2("UST trace session create successful");
 325
 326         return lus;
 327
 328 error:
 329         process_attr_tracker_destroy(lus->tracker_vpid);
 330         process_attr_tracker_destroy(lus->tracker_vuid);
 331         process_attr_tracker_destroy(lus->tracker_vgid);
 332         ht_cleanup_push(lus->domain_global.channels);
 333         ht_cleanup_push(lus->agents);
 334         free(lus);
 335 error_alloc:
 336         return NULL;
 337 }
 338
 339 /*
 340  * Allocate and initialize a ust channel data structure.
 341  *
 342  * Return pointer to structure or NULL.
 343  */
 344 struct ltt_ust_channel *trace_ust_create_channel(struct lttng_channel *chan,
 345                 enum lttng_domain_type domain)
 346 {
 347         struct ltt_ust_channel *luc;
 348
 349         assert(chan);
 350
 351         luc = zmalloc(sizeof(struct ltt_ust_channel));
 352         if (luc == NULL) {
 353                 PERROR("ltt_ust_channel zmalloc");
 354                 goto error;
 355         }
 356
 357         luc->domain = domain;
 358
 359         /* Copy UST channel attributes */
 360         luc->attr.overwrite = chan->attr.overwrite;
 361         luc->attr.subbuf_size = chan->attr.subbuf_size;
 362         luc->attr.num_subbuf = chan->attr.num_subbuf;
 363         luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
 364         luc->attr.read_timer_interval = chan->attr.read_timer_interval;
 365         luc->attr.output = (enum lttng_ust_output) chan->attr.output;
 366         luc->monitor_timer_interval = ((struct lttng_channel_extended *)
 367                         chan->attr.extended.ptr)->monitor_timer_interval;
 368         luc->attr.u.s.blocking_timeout = ((struct lttng_channel_extended *)
 369                         chan->attr.extended.ptr)->blocking_timeout;
 370
 371         /* Translate to UST output enum */
 372         switch (luc->attr.output) {
 373         default:
 374                 luc->attr.output = LTTNG_UST_MMAP;
 375                 break;
 376         }
 377
 378         /*
 379          * If we receive an empty string for channel name, it means the
 380          * default channel name is requested.
 381          */
 382         if (chan->name[0] == '\0') {
 383                 strncpy(luc->name, DEFAULT_CHANNEL_NAME, sizeof(luc->name));
 384         } else {
 385                 /* Copy channel name */
 386                 strncpy(luc->name, chan->name, sizeof(luc->name));
 387         }
 388         luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 389
 390         /* Init node */
 391         lttng_ht_node_init_str(&luc->node, luc->name);
 392         CDS_INIT_LIST_HEAD(&luc->ctx_list);
 393
 394         /* Alloc hash tables */
 395         luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 396         luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 397
 398         /* On-disk circular buffer parameters */
 399         luc->tracefile_size = chan->attr.tracefile_size;
 400         luc->tracefile_count = chan->attr.tracefile_count;
 401
 402         DBG2("Trace UST channel %s created", luc->name);
 403
 404 error:
 405         return luc;
 406 }
 407
 408 /*
 409  * Validates an exclusion list.
 410  *
 411  * Returns 0 if valid, negative value if invalid.
 412  */
 413 static int validate_exclusion(struct lttng_event_exclusion *exclusion)
 414 {
 415         size_t i;
 416         int ret = 0;
 417
 418         assert(exclusion);
 419
 420         for (i = 0; i < exclusion->count; ++i) {
 421                 size_t j;
 422                 const char *name_a =
 423                         LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, i);
 424
 425                 for (j = 0; j < i; ++j) {
 426                         const char *name_b =
 427                                 LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, j);
 428
 429                         if (!strncmp(name_a, name_b, LTTNG_SYMBOL_NAME_LEN)) {
 430                                 /* Match! */
 431                                 ret = -1;
 432                                 goto end;
 433                         }
 434                 }
 435         }
 436
 437 end:
 438         return ret;
 439 }
 440
 441 /*
 442  * Allocate and initialize a ust event. Set name and event type.
 443  * We own filter_expression, filter, and exclusion.
 444  *
 445  * Return an lttng_error_code
 446  */
 447 enum lttng_error_code trace_ust_create_event(struct lttng_event *ev,
 448                 char *filter_expression,
 449                 struct lttng_filter_bytecode *filter,
 450                 struct lttng_event_exclusion *exclusion,
 451                 bool internal_event,
 452                 struct ltt_ust_event **ust_event)
 453 {
 454         struct ltt_ust_event *local_ust_event;
 455         enum lttng_error_code ret = LTTNG_OK;
 456
 457         assert(ev);
 458
 459         if (exclusion && validate_exclusion(exclusion)) {
 460                 ret = LTTNG_ERR_INVALID;
 461                 goto error;
 462         }
 463
 464         local_ust_event = zmalloc(sizeof(struct ltt_ust_event));
 465         if (local_ust_event == NULL) {
 466                 PERROR("ust event zmalloc");
 467                 ret = LTTNG_ERR_NOMEM;
 468                 goto error;
 469         }
 470
 471         local_ust_event->internal = internal_event;
 472
 473         switch (ev->type) {
 474         case LTTNG_EVENT_PROBE:
 475                 local_ust_event->attr.instrumentation = LTTNG_UST_PROBE;
 476                 break;
 477         case LTTNG_EVENT_FUNCTION:
 478                 local_ust_event->attr.instrumentation = LTTNG_UST_FUNCTION;
 479                 break;
 480         case LTTNG_EVENT_FUNCTION_ENTRY:
 481                 local_ust_event->attr.instrumentation = LTTNG_UST_FUNCTION;
 482                 break;
 483         case LTTNG_EVENT_TRACEPOINT:
 484                 local_ust_event->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 485                 break;
 486         default:
 487                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 488                 ret = LTTNG_ERR_INVALID;
 489                 goto error_free_event;
 490         }
 491
 492         /* Copy event name */
 493         strncpy(local_ust_event->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 494         local_ust_event->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 495
 496         switch (ev->loglevel_type) {
 497         case LTTNG_EVENT_LOGLEVEL_ALL:
 498                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 499                 local_ust_event->attr.loglevel = -1;    /* Force to -1 */
 500                 break;
 501         case LTTNG_EVENT_LOGLEVEL_RANGE:
 502                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 503                 local_ust_event->attr.loglevel = ev->loglevel;
 504                 break;
 505         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 506                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 507                 local_ust_event->attr.loglevel = ev->loglevel;
 508                 break;
 509         default:
 510                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 511                 ret = LTTNG_ERR_INVALID;
 512                 goto error_free_event;
 513         }
 514
 515         /* Same layout. */
 516         local_ust_event->filter_expression = filter_expression;
 517         local_ust_event->filter = filter;
 518         local_ust_event->exclusion = exclusion;
 519
 520         /* Init node */
 521         lttng_ht_node_init_str(&local_ust_event->node, local_ust_event->attr.name);
 522
 523         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 524                 local_ust_event->attr.name, local_ust_event->attr.loglevel_type,
 525                 local_ust_event->attr.loglevel);
 526
 527         *ust_event = local_ust_event;
 528
 529         return ret;
 530
 531 error_free_event:
 532         free(local_ust_event);
 533 error:
 534         free(filter_expression);
 535         free(filter);
 536         free(exclusion);
 537         return ret;
 538 }
 539
 540 static
 541 int trace_ust_context_type_event_to_ust(
 542                 enum lttng_event_context_type type)
 543 {
 544         int utype;
 545
 546         switch (type) {
 547         case LTTNG_EVENT_CONTEXT_VTID:
 548                 utype = LTTNG_UST_CONTEXT_VTID;
 549                 break;
 550         case LTTNG_EVENT_CONTEXT_VPID:
 551                 utype = LTTNG_UST_CONTEXT_VPID;
 552                 break;
 553         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 554                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 555                 break;
 556         case LTTNG_EVENT_CONTEXT_PROCNAME:
 557                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 558                 break;
 559         case LTTNG_EVENT_CONTEXT_IP:
 560                 utype = LTTNG_UST_CONTEXT_IP;
 561                 break;
 562         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 563                 if (!ustctl_has_perf_counters()) {
 564                         utype = -1;
 565                         WARN("Perf counters not implemented in UST");
 566                 } else {
 567                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 568                 }
 569                 break;
 570         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
 571                 utype = LTTNG_UST_CONTEXT_APP_CONTEXT;
 572                 break;
 573         case LTTNG_EVENT_CONTEXT_CGROUP_NS:
 574                 utype = LTTNG_UST_CONTEXT_CGROUP_NS;
 575                 break;
 576         case LTTNG_EVENT_CONTEXT_IPC_NS:
 577                 utype = LTTNG_UST_CONTEXT_IPC_NS;
 578                 break;
 579         case LTTNG_EVENT_CONTEXT_MNT_NS:
 580                 utype = LTTNG_UST_CONTEXT_MNT_NS;
 581                 break;
 582         case LTTNG_EVENT_CONTEXT_NET_NS:
 583                 utype = LTTNG_UST_CONTEXT_NET_NS;
 584                 break;
 585         case LTTNG_EVENT_CONTEXT_PID_NS:
 586                 utype = LTTNG_UST_CONTEXT_PID_NS;
 587                 break;
 588         case LTTNG_EVENT_CONTEXT_TIME_NS:
 589                 utype = LTTNG_UST_CONTEXT_TIME_NS;
 590                 break;
 591         case LTTNG_EVENT_CONTEXT_USER_NS:
 592                 utype = LTTNG_UST_CONTEXT_USER_NS;
 593                 break;
 594         case LTTNG_EVENT_CONTEXT_UTS_NS:
 595                 utype = LTTNG_UST_CONTEXT_UTS_NS;
 596                 break;
 597         case LTTNG_EVENT_CONTEXT_VUID:
 598                 utype = LTTNG_UST_CONTEXT_VUID;
 599                 break;
 600         case LTTNG_EVENT_CONTEXT_VEUID:
 601                 utype = LTTNG_UST_CONTEXT_VEUID;
 602                 break;
 603         case LTTNG_EVENT_CONTEXT_VSUID:
 604                 utype = LTTNG_UST_CONTEXT_VSUID;
 605                 break;
 606         case LTTNG_EVENT_CONTEXT_VGID:
 607                 utype = LTTNG_UST_CONTEXT_VGID;
 608                 break;
 609         case LTTNG_EVENT_CONTEXT_VEGID:
 610                 utype = LTTNG_UST_CONTEXT_VEGID;
 611                 break;
 612         case LTTNG_EVENT_CONTEXT_VSGID:
 613                 utype = LTTNG_UST_CONTEXT_VSGID;
 614                 break;
 615         default:
 616                 utype = -1;
 617                 break;
 618         }
 619         return utype;
 620 }
 621
 622 /*
 623  * Return 1 if contexts match, 0 otherwise.
 624  */
 625 int trace_ust_match_context(const struct ltt_ust_context *uctx,
 626                 const struct lttng_event_context *ctx)
 627 {
 628         int utype;
 629
 630         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 631         if (utype < 0) {
 632                 return 0;
 633         }
 634         if (uctx->ctx.ctx != utype) {
 635                 return 0;
 636         }
 637         switch (utype) {
 638         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 639                 if (uctx->ctx.u.perf_counter.type
 640                                 != ctx->u.perf_counter.type) {
 641                         return 0;
 642                 }
 643                 if (uctx->ctx.u.perf_counter.config
 644                                 != ctx->u.perf_counter.config) {
 645                         return 0;
 646                 }
 647                 if (strncmp(uctx->ctx.u.perf_counter.name,
 648                                 ctx->u.perf_counter.name,
 649                                 LTTNG_UST_SYM_NAME_LEN)) {
 650                         return 0;
 651                 }
 652                 break;
 653         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 654                 assert(uctx->ctx.u.app_ctx.provider_name);
 655                 assert(uctx->ctx.u.app_ctx.ctx_name);
 656                 if (strcmp(uctx->ctx.u.app_ctx.provider_name,
 657                                 ctx->u.app_ctx.provider_name) ||
 658                                 strcmp(uctx->ctx.u.app_ctx.ctx_name,
 659                                 ctx->u.app_ctx.ctx_name)) {
 660                         return 0;
 661                 }
 662         default:
 663                 break;
 664
 665         }
 666         return 1;
 667 }
 668
 669 /*
 670  * Allocate and initialize an UST context.
 671  *
 672  * Return pointer to structure or NULL.
 673  */
 674 struct ltt_ust_context *trace_ust_create_context(
 675                 const struct lttng_event_context *ctx)
 676 {
 677         struct ltt_ust_context *uctx = NULL;
 678         int utype;
 679
 680         assert(ctx);
 681
 682         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 683         if (utype < 0) {
 684                 ERR("Invalid UST context");
 685                 goto end;
 686         }
 687
 688         uctx = zmalloc(sizeof(struct ltt_ust_context));
 689         if (!uctx) {
 690                 PERROR("zmalloc ltt_ust_context");
 691                 goto end;
 692         }
 693
 694         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 695         switch (utype) {
 696         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 697                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 698                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 699                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 700                                 LTTNG_UST_SYM_NAME_LEN);
 701                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 702                 break;
 703         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 704         {
 705                 char *provider_name = NULL, *ctx_name = NULL;
 706
 707                 provider_name = strdup(ctx->u.app_ctx.provider_name);
 708                 if (!provider_name) {
 709                         goto error;
 710                 }
 711                 uctx->ctx.u.app_ctx.provider_name = provider_name;
 712
 713                 ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 714                 if (!ctx_name) {
 715                         goto error;
 716                 }
 717                 uctx->ctx.u.app_ctx.ctx_name = ctx_name;
 718                 break;
 719         }
 720         default:
 721                 break;
 722         }
 723         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 724 end:
 725         return uctx;
 726 error:
 727         trace_ust_destroy_context(uctx);
 728         return NULL;
 729 }
 730
 731 static void destroy_id_tracker_node_rcu(struct rcu_head *head)
 732 {
 733         struct ust_id_tracker_node *tracker_node = caa_container_of(
 734                         head, struct ust_id_tracker_node, node.head);
 735         free(tracker_node);
 736 }
 737
 738 static void destroy_id_tracker_node(struct ust_id_tracker_node *tracker_node)
 739 {
 740         call_rcu(&tracker_node->node.head, destroy_id_tracker_node_rcu);
 741 }
 742
 743 static int init_id_tracker(struct ust_id_tracker *id_tracker)
 744 {
 745         int ret = LTTNG_OK;
 746
 747         id_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 748         if (!id_tracker->ht) {
 749                 ret = LTTNG_ERR_NOMEM;
 750                 goto end;
 751         }
 752
 753 end:
 754         return ret;
 755 }
 756
 757 /*
 758  * Teardown id tracker content, but don't free id_tracker object.
 759  */
 760 static void fini_id_tracker(struct ust_id_tracker *id_tracker)
 761 {
 762         struct ust_id_tracker_node *tracker_node;
 763         struct lttng_ht_iter iter;
 764
 765         if (!id_tracker->ht) {
 766                 return;
 767         }
 768         rcu_read_lock();
 769         cds_lfht_for_each_entry (id_tracker->ht->ht, &iter.iter, tracker_node,
 770                         node.node) {
 771                 int ret = lttng_ht_del(id_tracker->ht, &iter);
 772
 773                 assert(!ret);
 774                 destroy_id_tracker_node(tracker_node);
 775         }
 776         rcu_read_unlock();
 777         ht_cleanup_push(id_tracker->ht);
 778         id_tracker->ht = NULL;
 779 }
 780
 781 static struct ust_id_tracker_node *id_tracker_lookup(
 782                 struct ust_id_tracker *id_tracker,
 783                 int id,
 784                 struct lttng_ht_iter *iter)
 785 {
 786         unsigned long _id = (unsigned long) id;
 787         struct lttng_ht_node_ulong *node;
 788
 789         lttng_ht_lookup(id_tracker->ht, (void *) _id, iter);
 790         node = lttng_ht_iter_get_node_ulong(iter);
 791         if (node) {
 792                 return caa_container_of(node, struct ust_id_tracker_node, node);
 793         } else {
 794                 return NULL;
 795         }
 796 }
 797
 798 static int id_tracker_add_id(struct ust_id_tracker *id_tracker, int id)
 799 {
 800         int retval = LTTNG_OK;
 801         struct ust_id_tracker_node *tracker_node;
 802         struct lttng_ht_iter iter;
 803
 804         if (id < 0) {
 805                 retval = LTTNG_ERR_INVALID;
 806                 goto end;
 807         }
 808         tracker_node = id_tracker_lookup(id_tracker, id, &iter);
 809         if (tracker_node) {
 810                 /* Already exists. */
 811                 retval = LTTNG_ERR_PROCESS_ATTR_EXISTS;
 812                 goto end;
 813         }
 814         tracker_node = zmalloc(sizeof(*tracker_node));
 815         if (!tracker_node) {
 816                 retval = LTTNG_ERR_NOMEM;
 817                 goto end;
 818         }
 819         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) id);
 820         lttng_ht_add_unique_ulong(id_tracker->ht, &tracker_node->node);
 821 end:
 822         return retval;
 823 }
 824
 825 static int id_tracker_del_id(struct ust_id_tracker *id_tracker, int id)
 826 {
 827         int retval = LTTNG_OK, ret;
 828         struct ust_id_tracker_node *tracker_node;
 829         struct lttng_ht_iter iter;
 830
 831         if (id < 0) {
 832                 retval = LTTNG_ERR_INVALID;
 833                 goto end;
 834         }
 835         tracker_node = id_tracker_lookup(id_tracker, id, &iter);
 836         if (!tracker_node) {
 837                 /* Not found */
 838                 retval = LTTNG_ERR_PROCESS_ATTR_MISSING;
 839                 goto end;
 840         }
 841         ret = lttng_ht_del(id_tracker->ht, &iter);
 842         assert(!ret);
 843
 844         destroy_id_tracker_node(tracker_node);
 845 end:
 846         return retval;
 847 }
 848
 849 static struct ust_id_tracker *get_id_tracker(struct ltt_ust_session *session,
 850                 enum lttng_process_attr process_attr)
 851 {
 852         switch (process_attr) {
 853         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
 854                 return &session->vpid_tracker;
 855         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
 856                 return &session->vuid_tracker;
 857         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
 858                 return &session->vgid_tracker;
 859         default:
 860                 return NULL;
 861         }
 862 }
 863
 864 static struct process_attr_tracker *_trace_ust_get_process_attr_tracker(
 865                 struct ltt_ust_session *session,
 866                 enum lttng_process_attr process_attr)
 867 {
 868         switch (process_attr) {
 869         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
 870                 return session->tracker_vpid;
 871         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
 872                 return session->tracker_vuid;
 873         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
 874                 return session->tracker_vgid;
 875         default:
 876                 return NULL;
 877         }
 878 }
 879
 880 const struct process_attr_tracker *trace_ust_get_process_attr_tracker(
 881                 struct ltt_ust_session *session,
 882                 enum lttng_process_attr process_attr)
 883 {
 884         return (const struct process_attr_tracker *)
 885                         _trace_ust_get_process_attr_tracker(
 886                                         session, process_attr);
 887 }
 888
 889 /*
 890  * The session lock is held when calling this function.
 891  */
 892 int trace_ust_id_tracker_lookup(enum lttng_process_attr process_attr,
 893                 struct ltt_ust_session *session,
 894                 int id)
 895 {
 896         struct lttng_ht_iter iter;
 897         struct ust_id_tracker *id_tracker;
 898
 899         id_tracker = get_id_tracker(session, process_attr);
 900         if (!id_tracker) {
 901                 abort();
 902         }
 903         if (!id_tracker->ht) {
 904                 return 1;
 905         }
 906         if (id_tracker_lookup(id_tracker, id, &iter)) {
 907                 return 1;
 908         }
 909         return 0;
 910 }
 911
 912 /*
 913  * Called with the session lock held.
 914  */
 915 enum lttng_error_code trace_ust_process_attr_tracker_set_tracking_policy(
 916                 struct ltt_ust_session *session,
 917                 enum lttng_process_attr process_attr,
 918                 enum lttng_tracking_policy policy)
 919 {
 920         int ret;
 921         enum lttng_error_code ret_code = LTTNG_OK;
 922         struct ust_id_tracker *id_tracker =
 923                         get_id_tracker(session, process_attr);
 924         struct process_attr_tracker *tracker =
 925                         _trace_ust_get_process_attr_tracker(
 926                                         session, process_attr);
 927         bool should_update_apps = false;
 928         enum lttng_tracking_policy previous_policy;
 929
 930         if (!tracker) {
 931                 ret_code = LTTNG_ERR_INVALID;
 932                 goto end;
 933         }
 934
 935         previous_policy = process_attr_tracker_get_tracking_policy(tracker);
 936         ret = process_attr_tracker_set_tracking_policy(tracker, policy);
 937         if (ret) {
 938                 ret_code = LTTNG_ERR_UNK;
 939                 goto end;
 940         }
 941
 942         if (previous_policy == policy) {
 943                 goto end;
 944         }
 945
 946         switch (policy) {
 947         case LTTNG_TRACKING_POLICY_INCLUDE_ALL:
 948                 /* Track all values: destroy tracker if exists. */
 949                 if (id_tracker->ht) {
 950                         fini_id_tracker(id_tracker);
 951                         /* Ensure all apps have session. */
 952                         should_update_apps = true;
 953                 }
 954                 break;
 955         case LTTNG_TRACKING_POLICY_EXCLUDE_ALL:
 956         case LTTNG_TRACKING_POLICY_INCLUDE_SET:
 957                 /* fall-through. */
 958                 fini_id_tracker(id_tracker);
 959                 ret_code = init_id_tracker(id_tracker);
 960                 if (ret_code != LTTNG_OK) {
 961                         ERR("Error initializing ID tracker");
 962                         goto end;
 963                 }
 964                 /* Remove all apps from session. */
 965                 should_update_apps = true;
 966                 break;
 967         default:
 968                 abort();
 969         }
 970         if (should_update_apps && session->active) {
 971                 ust_app_global_update_all(session);
 972         }
 973 end:
 974         return ret_code;
 975 }
 976
 977 /* Called with the session lock held. */
 978 enum lttng_error_code trace_ust_process_attr_tracker_inclusion_set_add_value(
 979                 struct ltt_ust_session *session,
 980                 enum lttng_process_attr process_attr,
 981                 const struct process_attr_value *value)
 982 {
 983         enum lttng_error_code ret_code = LTTNG_OK;
 984         bool should_update_apps = false;
 985         struct ust_id_tracker *id_tracker =
 986                         get_id_tracker(session, process_attr);
 987         struct process_attr_tracker *tracker;
 988         int integral_value;
 989         enum process_attr_tracker_status status;
 990         struct ust_app *app;
 991
 992         /*
 993          * Convert process attribute tracker value to the integral
 994          * representation required by the kern-ctl API.
 995          */
 996         switch (process_attr) {
 997         case LTTNG_PROCESS_ATTR_PROCESS_ID:
 998         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
 999                 integral_value = (int) value->value.pid;
1000                 break;
1001         case LTTNG_PROCESS_ATTR_USER_ID:
1002         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
1003                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
1004                         uid_t uid;
1005
1006                         ret_code = utils_user_id_from_name(
1007                                         value->value.user_name, &uid);
1008                         if (ret_code != LTTNG_OK) {
1009                                 goto end;
1010                         }
1011                         integral_value = (int) uid;
1012                 } else {
1013                         integral_value = (int) value->value.uid;
1014                 }
1015                 break;
1016         case LTTNG_PROCESS_ATTR_GROUP_ID:
1017         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
1018                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
1019                         gid_t gid;
1020
1021                         ret_code = utils_group_id_from_name(
1022                                         value->value.group_name, &gid);
1023                         if (ret_code != LTTNG_OK) {
1024                                 goto end;
1025                         }
1026                         integral_value = (int) gid;
1027                 } else {
1028                         integral_value = (int) value->value.gid;
1029                 }
1030                 break;
1031         default:
1032                 ret_code = LTTNG_ERR_INVALID;
1033                 goto end;
1034         }
1035
1036         tracker = _trace_ust_get_process_attr_tracker(session, process_attr);
1037         if (!tracker) {
1038                 ret_code = LTTNG_ERR_INVALID;
1039                 goto end;
1040         }
1041
1042         status = process_attr_tracker_inclusion_set_add_value(tracker, value);
1043         if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
1044                 switch (status) {
1045                 case PROCESS_ATTR_TRACKER_STATUS_EXISTS:
1046                         ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
1047                         break;
1048                 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
1049                         ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
1050                         break;
1051                 case PROCESS_ATTR_TRACKER_STATUS_ERROR:
1052                 default:
1053                         ret_code = LTTNG_ERR_UNK;
1054                         break;
1055                 }
1056                 goto end;
1057         }
1058
1059         DBG("User space track %s %d for session id %" PRIu64,
1060                         lttng_process_attr_to_string(process_attr),
1061                         integral_value, session->id);
1062
1063         ret_code = id_tracker_add_id(id_tracker, integral_value);
1064         if (ret_code != LTTNG_OK) {
1065                 goto end;
1066         }
1067         /* Add session to application */
1068         switch (process_attr) {
1069         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
1070                 app = ust_app_find_by_pid(integral_value);
1071                 if (app) {
1072                         should_update_apps = true;
1073                 }
1074                 break;
1075         default:
1076                 should_update_apps = true;
1077                 break;
1078         }
1079         if (should_update_apps && session->active) {
1080                 ust_app_global_update_all(session);
1081         }
1082 end:
1083         return ret_code;
1084 }
1085
1086 /* Called with the session lock held. */
1087 enum lttng_error_code trace_ust_process_attr_tracker_inclusion_set_remove_value(
1088                 struct ltt_ust_session *session,
1089                 enum lttng_process_attr process_attr,
1090                 const struct process_attr_value *value)
1091 {
1092         enum lttng_error_code ret_code = LTTNG_OK;
1093         bool should_update_apps = false;
1094         struct ust_id_tracker *id_tracker =
1095                         get_id_tracker(session, process_attr);
1096         struct process_attr_tracker *tracker;
1097         int integral_value;
1098         enum process_attr_tracker_status status;
1099         struct ust_app *app;
1100
1101         /*
1102          * Convert process attribute tracker value to the integral
1103          * representation required by the kern-ctl API.
1104          */
1105         switch (process_attr) {
1106         case LTTNG_PROCESS_ATTR_PROCESS_ID:
1107         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
1108                 integral_value = (int) value->value.pid;
1109                 break;
1110         case LTTNG_PROCESS_ATTR_USER_ID:
1111         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
1112                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
1113                         uid_t uid;
1114
1115                         ret_code = utils_user_id_from_name(
1116                                         value->value.user_name, &uid);
1117                         if (ret_code != LTTNG_OK) {
1118                                 goto end;
1119                         }
1120                         integral_value = (int) uid;
1121                 } else {
1122                         integral_value = (int) value->value.uid;
1123                 }
1124                 break;
1125         case LTTNG_PROCESS_ATTR_GROUP_ID:
1126         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
1127                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
1128                         gid_t gid;
1129
1130                         ret_code = utils_group_id_from_name(
1131                                         value->value.group_name, &gid);
1132                         if (ret_code != LTTNG_OK) {
1133                                 goto end;
1134                         }
1135                         integral_value = (int) gid;
1136                 } else {
1137                         integral_value = (int) value->value.gid;
1138                 }
1139                 break;
1140         default:
1141                 ret_code = LTTNG_ERR_INVALID;
1142                 goto end;
1143         }
1144
1145         tracker = _trace_ust_get_process_attr_tracker(session, process_attr);
1146         if (!tracker) {
1147                 ret_code = LTTNG_ERR_INVALID;
1148                 goto end;
1149         }
1150
1151         status = process_attr_tracker_inclusion_set_remove_value(
1152                         tracker, value);
1153         if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
1154                 switch (status) {
1155                 case PROCESS_ATTR_TRACKER_STATUS_MISSING:
1156                         ret_code = LTTNG_ERR_PROCESS_ATTR_MISSING;
1157                         break;
1158                 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
1159                         ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
1160                         break;
1161                 case PROCESS_ATTR_TRACKER_STATUS_ERROR:
1162                 default:
1163                         ret_code = LTTNG_ERR_UNK;
1164                         break;
1165                 }
1166                 goto end;
1167         }
1168
1169         DBG("User space untrack %s %d for session id %" PRIu64,
1170                         lttng_process_attr_to_string(process_attr),
1171                         integral_value, session->id);
1172
1173         ret_code = id_tracker_del_id(id_tracker, integral_value);
1174         if (ret_code != LTTNG_OK) {
1175                 goto end;
1176         }
1177         /* Add session to application */
1178         switch (process_attr) {
1179         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
1180                 app = ust_app_find_by_pid(integral_value);
1181                 if (app) {
1182                         should_update_apps = true;
1183                 }
1184                 break;
1185         default:
1186                 should_update_apps = true;
1187                 break;
1188         }
1189         if (should_update_apps && session->active) {
1190                 ust_app_global_update_all(session);
1191         }
1192 end:
1193         return ret_code;
1194 }
1195
1196 /*
1197  * RCU safe free context structure.
1198  */
1199 static void destroy_context_rcu(struct rcu_head *head)
1200 {
1201         struct lttng_ht_node_ulong *node =
1202                 caa_container_of(head, struct lttng_ht_node_ulong, head);
1203         struct ltt_ust_context *ctx =
1204                 caa_container_of(node, struct ltt_ust_context, node);
1205
1206         trace_ust_destroy_context(ctx);
1207 }
1208
1209 /*
1210  * Cleanup UST context hash table.
1211  */
1212 static void destroy_contexts(struct lttng_ht *ht)
1213 {
1214         int ret;
1215         struct lttng_ht_node_ulong *node;
1216         struct lttng_ht_iter iter;
1217         struct ltt_ust_context *ctx;
1218
1219         assert(ht);
1220
1221         rcu_read_lock();
1222         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
1223                 /* Remove from ordered list. */
1224                 ctx = caa_container_of(node, struct ltt_ust_context, node);
1225                 cds_list_del(&ctx->list);
1226                 /* Remove from channel's hash table. */
1227                 ret = lttng_ht_del(ht, &iter);
1228                 if (!ret) {
1229                         call_rcu(&node->head, destroy_context_rcu);
1230                 }
1231         }
1232         rcu_read_unlock();
1233
1234         ht_cleanup_push(ht);
1235 }
1236
1237 /*
1238  * Cleanup ust event structure.
1239  */
1240 void trace_ust_destroy_event(struct ltt_ust_event *event)
1241 {
1242         assert(event);
1243
1244         DBG2("Trace destroy UST event %s", event->attr.name);
1245         free(event->filter_expression);
1246         free(event->filter);
1247         free(event->exclusion);
1248         free(event);
1249 }
1250
1251 /*
1252  * Cleanup ust context structure.
1253  */
1254 void trace_ust_destroy_context(struct ltt_ust_context *ctx)
1255 {
1256         assert(ctx);
1257
1258         if (ctx->ctx.ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1259                 free(ctx->ctx.u.app_ctx.provider_name);
1260                 free(ctx->ctx.u.app_ctx.ctx_name);
1261         }
1262         free(ctx);
1263 }
1264
1265 /*
1266  * URCU intermediate call to complete destroy event.
1267  */
1268 static void destroy_event_rcu(struct rcu_head *head)
1269 {
1270         struct lttng_ht_node_str *node =
1271                 caa_container_of(head, struct lttng_ht_node_str, head);
1272         struct ltt_ust_event *event =
1273                 caa_container_of(node, struct ltt_ust_event, node);
1274
1275         trace_ust_destroy_event(event);
1276 }
1277
1278 /*
1279  * Cleanup UST events hashtable.
1280  */
1281 static void destroy_events(struct lttng_ht *events)
1282 {
1283         int ret;
1284         struct lttng_ht_node_str *node;
1285         struct lttng_ht_iter iter;
1286
1287         assert(events);
1288
1289         rcu_read_lock();
1290         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1291                 ret = lttng_ht_del(events, &iter);
1292                 assert(!ret);
1293                 call_rcu(&node->head, destroy_event_rcu);
1294         }
1295         rcu_read_unlock();
1296
1297         ht_cleanup_push(events);
1298 }
1299
1300 /*
1301  * Cleanup ust channel structure.
1302  *
1303  * Should _NOT_ be called with RCU read lock held.
1304  */
1305 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1306 {
1307         assert(channel);
1308
1309         DBG2("Trace destroy UST channel %s", channel->name);
1310
1311         free(channel);
1312 }
1313
1314 /*
1315  * URCU intermediate call to complete destroy channel.
1316  */
1317 static void destroy_channel_rcu(struct rcu_head *head)
1318 {
1319         struct lttng_ht_node_str *node =
1320                 caa_container_of(head, struct lttng_ht_node_str, head);
1321         struct ltt_ust_channel *channel =
1322                 caa_container_of(node, struct ltt_ust_channel, node);
1323
1324         _trace_ust_destroy_channel(channel);
1325 }
1326
1327 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1328 {
1329         /* Destroying all events of the channel */
1330         destroy_events(channel->events);
1331         /* Destroying all context of the channel */
1332         destroy_contexts(channel->ctx);
1333
1334         call_rcu(&channel->node.head, destroy_channel_rcu);
1335 }
1336
1337 /*
1338  * Remove an UST channel from a channel HT.
1339  */
1340 void trace_ust_delete_channel(struct lttng_ht *ht,
1341                 struct ltt_ust_channel *channel)
1342 {
1343         int ret;
1344         struct lttng_ht_iter iter;
1345
1346         assert(ht);
1347         assert(channel);
1348
1349         iter.iter.node = &channel->node.node;
1350         ret = lttng_ht_del(ht, &iter);
1351         assert(!ret);
1352 }
1353
1354 /*
1355  * Iterate over a hash table containing channels and cleanup safely.
1356  */
1357 static void destroy_channels(struct lttng_ht *channels)
1358 {
1359         struct lttng_ht_node_str *node;
1360         struct lttng_ht_iter iter;
1361
1362         assert(channels);
1363
1364         rcu_read_lock();
1365         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1366                 struct ltt_ust_channel *chan =
1367                         caa_container_of(node, struct ltt_ust_channel, node);
1368
1369                 trace_ust_delete_channel(channels, chan);
1370                 trace_ust_destroy_channel(chan);
1371         }
1372         rcu_read_unlock();
1373
1374         ht_cleanup_push(channels);
1375 }
1376
1377 /*
1378  * Cleanup UST global domain.
1379  */
1380 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1381 {
1382         assert(dom);
1383
1384         destroy_channels(dom->channels);
1385 }
1386
1387 /*
1388  * Cleanup ust session structure, keeping data required by
1389  * destroy notifier.
1390  *
1391  * Should *NOT* be called with RCU read-side lock held.
1392  */
1393 void trace_ust_destroy_session(struct ltt_ust_session *session)
1394 {
1395         struct agent *agt;
1396         struct buffer_reg_uid *reg, *sreg;
1397         struct lttng_ht_iter iter;
1398
1399         assert(session);
1400
1401         DBG2("Trace UST destroy session %" PRIu64, session->id);
1402
1403         /* Cleaning up UST domain */
1404         destroy_domain_global(&session->domain_global);
1405
1406         rcu_read_lock();
1407         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1408                 int ret = lttng_ht_del(session->agents, &iter);
1409
1410                 assert(!ret);
1411                 agent_destroy(agt);
1412         }
1413         rcu_read_unlock();
1414
1415         ht_cleanup_push(session->agents);
1416
1417         /* Cleanup UID buffer registry object(s). */
1418         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1419                         lnode) {
1420                 cds_list_del(&reg->lnode);
1421                 buffer_reg_uid_remove(reg);
1422                 buffer_reg_uid_destroy(reg, session->consumer);
1423         }
1424
1425         process_attr_tracker_destroy(session->tracker_vpid);
1426         process_attr_tracker_destroy(session->tracker_vuid);
1427         process_attr_tracker_destroy(session->tracker_vgid);
1428
1429         fini_id_tracker(&session->vpid_tracker);
1430         fini_id_tracker(&session->vuid_tracker);
1431         fini_id_tracker(&session->vgid_tracker);
1432         lttng_trace_chunk_put(session->current_trace_chunk);
1433 }
1434
1435 /* Free elements needed by destroy notifiers. */
1436 void trace_ust_free_session(struct ltt_ust_session *session)
1437 {
1438         consumer_output_put(session->consumer);
1439         free(session);
1440 }