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_USER_NS:
 589                 utype = LTTNG_UST_CONTEXT_USER_NS;
 590                 break;
 591         case LTTNG_EVENT_CONTEXT_UTS_NS:
 592                 utype = LTTNG_UST_CONTEXT_UTS_NS;
 593                 break;
 594         case LTTNG_EVENT_CONTEXT_VUID:
 595                 utype = LTTNG_UST_CONTEXT_VUID;
 596                 break;
 597         case LTTNG_EVENT_CONTEXT_VEUID:
 598                 utype = LTTNG_UST_CONTEXT_VEUID;
 599                 break;
 600         case LTTNG_EVENT_CONTEXT_VSUID:
 601                 utype = LTTNG_UST_CONTEXT_VSUID;
 602                 break;
 603         case LTTNG_EVENT_CONTEXT_VGID:
 604                 utype = LTTNG_UST_CONTEXT_VGID;
 605                 break;
 606         case LTTNG_EVENT_CONTEXT_VEGID:
 607                 utype = LTTNG_UST_CONTEXT_VEGID;
 608                 break;
 609         case LTTNG_EVENT_CONTEXT_VSGID:
 610                 utype = LTTNG_UST_CONTEXT_VSGID;
 611                 break;
 612         default:
 613                 utype = -1;
 614                 break;
 615         }
 616         return utype;
 617 }
 618
 619 /*
 620  * Return 1 if contexts match, 0 otherwise.
 621  */
 622 int trace_ust_match_context(const struct ltt_ust_context *uctx,
 623                 const struct lttng_event_context *ctx)
 624 {
 625         int utype;
 626
 627         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 628         if (utype < 0) {
 629                 return 0;
 630         }
 631         if (uctx->ctx.ctx != utype) {
 632                 return 0;
 633         }
 634         switch (utype) {
 635         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 636                 if (uctx->ctx.u.perf_counter.type
 637                                 != ctx->u.perf_counter.type) {
 638                         return 0;
 639                 }
 640                 if (uctx->ctx.u.perf_counter.config
 641                                 != ctx->u.perf_counter.config) {
 642                         return 0;
 643                 }
 644                 if (strncmp(uctx->ctx.u.perf_counter.name,
 645                                 ctx->u.perf_counter.name,
 646                                 LTTNG_UST_SYM_NAME_LEN)) {
 647                         return 0;
 648                 }
 649                 break;
 650         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 651                 assert(uctx->ctx.u.app_ctx.provider_name);
 652                 assert(uctx->ctx.u.app_ctx.ctx_name);
 653                 if (strcmp(uctx->ctx.u.app_ctx.provider_name,
 654                                 ctx->u.app_ctx.provider_name) ||
 655                                 strcmp(uctx->ctx.u.app_ctx.ctx_name,
 656                                 ctx->u.app_ctx.ctx_name)) {
 657                         return 0;
 658                 }
 659         default:
 660                 break;
 661
 662         }
 663         return 1;
 664 }
 665
 666 /*
 667  * Allocate and initialize an UST context.
 668  *
 669  * Return pointer to structure or NULL.
 670  */
 671 struct ltt_ust_context *trace_ust_create_context(
 672                 const struct lttng_event_context *ctx)
 673 {
 674         struct ltt_ust_context *uctx = NULL;
 675         int utype;
 676
 677         assert(ctx);
 678
 679         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 680         if (utype < 0) {
 681                 ERR("Invalid UST context");
 682                 goto end;
 683         }
 684
 685         uctx = zmalloc(sizeof(struct ltt_ust_context));
 686         if (!uctx) {
 687                 PERROR("zmalloc ltt_ust_context");
 688                 goto end;
 689         }
 690
 691         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 692         switch (utype) {
 693         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 694                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 695                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 696                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 697                                 LTTNG_UST_SYM_NAME_LEN);
 698                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 699                 break;
 700         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 701         {
 702                 char *provider_name = NULL, *ctx_name = NULL;
 703
 704                 provider_name = strdup(ctx->u.app_ctx.provider_name);
 705                 if (!provider_name) {
 706                         goto error;
 707                 }
 708                 uctx->ctx.u.app_ctx.provider_name = provider_name;
 709
 710                 ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 711                 if (!ctx_name) {
 712                         goto error;
 713                 }
 714                 uctx->ctx.u.app_ctx.ctx_name = ctx_name;
 715                 break;
 716         }
 717         default:
 718                 break;
 719         }
 720         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 721 end:
 722         return uctx;
 723 error:
 724         trace_ust_destroy_context(uctx);
 725         return NULL;
 726 }
 727
 728 static void destroy_id_tracker_node_rcu(struct rcu_head *head)
 729 {
 730         struct ust_id_tracker_node *tracker_node = caa_container_of(
 731                         head, struct ust_id_tracker_node, node.head);
 732         free(tracker_node);
 733 }
 734
 735 static void destroy_id_tracker_node(struct ust_id_tracker_node *tracker_node)
 736 {
 737         call_rcu(&tracker_node->node.head, destroy_id_tracker_node_rcu);
 738 }
 739
 740 static int init_id_tracker(struct ust_id_tracker *id_tracker)
 741 {
 742         int ret = LTTNG_OK;
 743
 744         id_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 745         if (!id_tracker->ht) {
 746                 ret = LTTNG_ERR_NOMEM;
 747                 goto end;
 748         }
 749
 750 end:
 751         return ret;
 752 }
 753
 754 /*
 755  * Teardown id tracker content, but don't free id_tracker object.
 756  */
 757 static void fini_id_tracker(struct ust_id_tracker *id_tracker)
 758 {
 759         struct ust_id_tracker_node *tracker_node;
 760         struct lttng_ht_iter iter;
 761
 762         if (!id_tracker->ht) {
 763                 return;
 764         }
 765         rcu_read_lock();
 766         cds_lfht_for_each_entry (id_tracker->ht->ht, &iter.iter, tracker_node,
 767                         node.node) {
 768                 int ret = lttng_ht_del(id_tracker->ht, &iter);
 769
 770                 assert(!ret);
 771                 destroy_id_tracker_node(tracker_node);
 772         }
 773         rcu_read_unlock();
 774         ht_cleanup_push(id_tracker->ht);
 775         id_tracker->ht = NULL;
 776 }
 777
 778 static struct ust_id_tracker_node *id_tracker_lookup(
 779                 struct ust_id_tracker *id_tracker,
 780                 int id,
 781                 struct lttng_ht_iter *iter)
 782 {
 783         unsigned long _id = (unsigned long) id;
 784         struct lttng_ht_node_ulong *node;
 785
 786         lttng_ht_lookup(id_tracker->ht, (void *) _id, iter);
 787         node = lttng_ht_iter_get_node_ulong(iter);
 788         if (node) {
 789                 return caa_container_of(node, struct ust_id_tracker_node, node);
 790         } else {
 791                 return NULL;
 792         }
 793 }
 794
 795 static int id_tracker_add_id(struct ust_id_tracker *id_tracker, int id)
 796 {
 797         int retval = LTTNG_OK;
 798         struct ust_id_tracker_node *tracker_node;
 799         struct lttng_ht_iter iter;
 800
 801         if (id < 0) {
 802                 retval = LTTNG_ERR_INVALID;
 803                 goto end;
 804         }
 805         tracker_node = id_tracker_lookup(id_tracker, id, &iter);
 806         if (tracker_node) {
 807                 /* Already exists. */
 808                 retval = LTTNG_ERR_PROCESS_ATTR_EXISTS;
 809                 goto end;
 810         }
 811         tracker_node = zmalloc(sizeof(*tracker_node));
 812         if (!tracker_node) {
 813                 retval = LTTNG_ERR_NOMEM;
 814                 goto end;
 815         }
 816         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) id);
 817         lttng_ht_add_unique_ulong(id_tracker->ht, &tracker_node->node);
 818 end:
 819         return retval;
 820 }
 821
 822 static int id_tracker_del_id(struct ust_id_tracker *id_tracker, int id)
 823 {
 824         int retval = LTTNG_OK, ret;
 825         struct ust_id_tracker_node *tracker_node;
 826         struct lttng_ht_iter iter;
 827
 828         if (id < 0) {
 829                 retval = LTTNG_ERR_INVALID;
 830                 goto end;
 831         }
 832         tracker_node = id_tracker_lookup(id_tracker, id, &iter);
 833         if (!tracker_node) {
 834                 /* Not found */
 835                 retval = LTTNG_ERR_PROCESS_ATTR_MISSING;
 836                 goto end;
 837         }
 838         ret = lttng_ht_del(id_tracker->ht, &iter);
 839         assert(!ret);
 840
 841         destroy_id_tracker_node(tracker_node);
 842 end:
 843         return retval;
 844 }
 845
 846 static struct ust_id_tracker *get_id_tracker(struct ltt_ust_session *session,
 847                 enum lttng_process_attr process_attr)
 848 {
 849         switch (process_attr) {
 850         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
 851                 return &session->vpid_tracker;
 852         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
 853                 return &session->vuid_tracker;
 854         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
 855                 return &session->vgid_tracker;
 856         default:
 857                 return NULL;
 858         }
 859 }
 860
 861 static struct process_attr_tracker *_trace_ust_get_process_attr_tracker(
 862                 struct ltt_ust_session *session,
 863                 enum lttng_process_attr process_attr)
 864 {
 865         switch (process_attr) {
 866         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
 867                 return session->tracker_vpid;
 868         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
 869                 return session->tracker_vuid;
 870         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
 871                 return session->tracker_vgid;
 872         default:
 873                 return NULL;
 874         }
 875 }
 876
 877 const struct process_attr_tracker *trace_ust_get_process_attr_tracker(
 878                 struct ltt_ust_session *session,
 879                 enum lttng_process_attr process_attr)
 880 {
 881         return (const struct process_attr_tracker *)
 882                         _trace_ust_get_process_attr_tracker(
 883                                         session, process_attr);
 884 }
 885
 886 /*
 887  * The session lock is held when calling this function.
 888  */
 889 int trace_ust_id_tracker_lookup(enum lttng_process_attr process_attr,
 890                 struct ltt_ust_session *session,
 891                 int id)
 892 {
 893         struct lttng_ht_iter iter;
 894         struct ust_id_tracker *id_tracker;
 895
 896         id_tracker = get_id_tracker(session, process_attr);
 897         if (!id_tracker) {
 898                 abort();
 899         }
 900         if (!id_tracker->ht) {
 901                 return 1;
 902         }
 903         if (id_tracker_lookup(id_tracker, id, &iter)) {
 904                 return 1;
 905         }
 906         return 0;
 907 }
 908
 909 /*
 910  * Called with the session lock held.
 911  */
 912 enum lttng_error_code trace_ust_process_attr_tracker_set_tracking_policy(
 913                 struct ltt_ust_session *session,
 914                 enum lttng_process_attr process_attr,
 915                 enum lttng_tracking_policy policy)
 916 {
 917         int ret;
 918         enum lttng_error_code ret_code = LTTNG_OK;
 919         struct ust_id_tracker *id_tracker =
 920                         get_id_tracker(session, process_attr);
 921         struct process_attr_tracker *tracker =
 922                         _trace_ust_get_process_attr_tracker(
 923                                         session, process_attr);
 924         bool should_update_apps = false;
 925         enum lttng_tracking_policy previous_policy;
 926
 927         if (!tracker) {
 928                 ret_code = LTTNG_ERR_INVALID;
 929                 goto end;
 930         }
 931
 932         previous_policy = process_attr_tracker_get_tracking_policy(tracker);
 933         ret = process_attr_tracker_set_tracking_policy(tracker, policy);
 934         if (ret) {
 935                 ret_code = LTTNG_ERR_UNK;
 936                 goto end;
 937         }
 938
 939         if (previous_policy == policy) {
 940                 goto end;
 941         }
 942
 943         switch (policy) {
 944         case LTTNG_TRACKING_POLICY_INCLUDE_ALL:
 945                 /* Track all values: destroy tracker if exists. */
 946                 if (id_tracker->ht) {
 947                         fini_id_tracker(id_tracker);
 948                         /* Ensure all apps have session. */
 949                         should_update_apps = true;
 950                 }
 951                 break;
 952         case LTTNG_TRACKING_POLICY_EXCLUDE_ALL:
 953         case LTTNG_TRACKING_POLICY_INCLUDE_SET:
 954                 /* fall-through. */
 955                 fini_id_tracker(id_tracker);
 956                 ret_code = init_id_tracker(id_tracker);
 957                 if (ret_code != LTTNG_OK) {
 958                         ERR("Error initializing ID tracker");
 959                         goto end;
 960                 }
 961                 /* Remove all apps from session. */
 962                 should_update_apps = true;
 963                 break;
 964         default:
 965                 abort();
 966         }
 967         if (should_update_apps && session->active) {
 968                 ust_app_global_update_all(session);
 969         }
 970 end:
 971         return ret_code;
 972 }
 973
 974 /* Called with the session lock held. */
 975 enum lttng_error_code trace_ust_process_attr_tracker_inclusion_set_add_value(
 976                 struct ltt_ust_session *session,
 977                 enum lttng_process_attr process_attr,
 978                 const struct process_attr_value *value)
 979 {
 980         enum lttng_error_code ret_code = LTTNG_OK;
 981         bool should_update_apps = false;
 982         struct ust_id_tracker *id_tracker =
 983                         get_id_tracker(session, process_attr);
 984         struct process_attr_tracker *tracker;
 985         int integral_value;
 986         enum process_attr_tracker_status status;
 987         struct ust_app *app;
 988
 989         /*
 990          * Convert process attribute tracker value to the integral
 991          * representation required by the kern-ctl API.
 992          */
 993         switch (process_attr) {
 994         case LTTNG_PROCESS_ATTR_PROCESS_ID:
 995         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
 996                 integral_value = (int) value->value.pid;
 997                 break;
 998         case LTTNG_PROCESS_ATTR_USER_ID:
 999         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
1000                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
1001                         uid_t uid;
1002
1003                         ret_code = utils_user_id_from_name(
1004                                         value->value.user_name, &uid);
1005                         if (ret_code != LTTNG_OK) {
1006                                 goto end;
1007                         }
1008                         integral_value = (int) uid;
1009                 } else {
1010                         integral_value = (int) value->value.uid;
1011                 }
1012                 break;
1013         case LTTNG_PROCESS_ATTR_GROUP_ID:
1014         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
1015                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
1016                         gid_t gid;
1017
1018                         ret_code = utils_group_id_from_name(
1019                                         value->value.group_name, &gid);
1020                         if (ret_code != LTTNG_OK) {
1021                                 goto end;
1022                         }
1023                         integral_value = (int) gid;
1024                 } else {
1025                         integral_value = (int) value->value.gid;
1026                 }
1027                 break;
1028         default:
1029                 ret_code = LTTNG_ERR_INVALID;
1030                 goto end;
1031         }
1032
1033         tracker = _trace_ust_get_process_attr_tracker(session, process_attr);
1034         if (!tracker) {
1035                 ret_code = LTTNG_ERR_INVALID;
1036                 goto end;
1037         }
1038
1039         status = process_attr_tracker_inclusion_set_add_value(tracker, value);
1040         if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
1041                 switch (status) {
1042                 case PROCESS_ATTR_TRACKER_STATUS_EXISTS:
1043                         ret_code = LTTNG_ERR_PROCESS_ATTR_EXISTS;
1044                         break;
1045                 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
1046                         ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
1047                         break;
1048                 case PROCESS_ATTR_TRACKER_STATUS_ERROR:
1049                 default:
1050                         ret_code = LTTNG_ERR_UNK;
1051                         break;
1052                 }
1053                 goto end;
1054         }
1055
1056         DBG("User space track %s %d for session id %" PRIu64,
1057                         lttng_process_attr_to_string(process_attr),
1058                         integral_value, session->id);
1059
1060         ret_code = id_tracker_add_id(id_tracker, integral_value);
1061         if (ret_code != LTTNG_OK) {
1062                 goto end;
1063         }
1064         /* Add session to application */
1065         switch (process_attr) {
1066         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
1067                 app = ust_app_find_by_pid(integral_value);
1068                 if (app) {
1069                         should_update_apps = true;
1070                 }
1071                 break;
1072         default:
1073                 should_update_apps = true;
1074                 break;
1075         }
1076         if (should_update_apps && session->active) {
1077                 ust_app_global_update_all(session);
1078         }
1079 end:
1080         return ret_code;
1081 }
1082
1083 /* Called with the session lock held. */
1084 enum lttng_error_code trace_ust_process_attr_tracker_inclusion_set_remove_value(
1085                 struct ltt_ust_session *session,
1086                 enum lttng_process_attr process_attr,
1087                 const struct process_attr_value *value)
1088 {
1089         enum lttng_error_code ret_code = LTTNG_OK;
1090         bool should_update_apps = false;
1091         struct ust_id_tracker *id_tracker =
1092                         get_id_tracker(session, process_attr);
1093         struct process_attr_tracker *tracker;
1094         int integral_value;
1095         enum process_attr_tracker_status status;
1096         struct ust_app *app;
1097
1098         /*
1099          * Convert process attribute tracker value to the integral
1100          * representation required by the kern-ctl API.
1101          */
1102         switch (process_attr) {
1103         case LTTNG_PROCESS_ATTR_PROCESS_ID:
1104         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
1105                 integral_value = (int) value->value.pid;
1106                 break;
1107         case LTTNG_PROCESS_ATTR_USER_ID:
1108         case LTTNG_PROCESS_ATTR_VIRTUAL_USER_ID:
1109                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_USER_NAME) {
1110                         uid_t uid;
1111
1112                         ret_code = utils_user_id_from_name(
1113                                         value->value.user_name, &uid);
1114                         if (ret_code != LTTNG_OK) {
1115                                 goto end;
1116                         }
1117                         integral_value = (int) uid;
1118                 } else {
1119                         integral_value = (int) value->value.uid;
1120                 }
1121                 break;
1122         case LTTNG_PROCESS_ATTR_GROUP_ID:
1123         case LTTNG_PROCESS_ATTR_VIRTUAL_GROUP_ID:
1124                 if (value->type == LTTNG_PROCESS_ATTR_VALUE_TYPE_GROUP_NAME) {
1125                         gid_t gid;
1126
1127                         ret_code = utils_group_id_from_name(
1128                                         value->value.group_name, &gid);
1129                         if (ret_code != LTTNG_OK) {
1130                                 goto end;
1131                         }
1132                         integral_value = (int) gid;
1133                 } else {
1134                         integral_value = (int) value->value.gid;
1135                 }
1136                 break;
1137         default:
1138                 ret_code = LTTNG_ERR_INVALID;
1139                 goto end;
1140         }
1141
1142         tracker = _trace_ust_get_process_attr_tracker(session, process_attr);
1143         if (!tracker) {
1144                 ret_code = LTTNG_ERR_INVALID;
1145                 goto end;
1146         }
1147
1148         status = process_attr_tracker_inclusion_set_remove_value(
1149                         tracker, value);
1150         if (status != PROCESS_ATTR_TRACKER_STATUS_OK) {
1151                 switch (status) {
1152                 case PROCESS_ATTR_TRACKER_STATUS_MISSING:
1153                         ret_code = LTTNG_ERR_PROCESS_ATTR_MISSING;
1154                         break;
1155                 case PROCESS_ATTR_TRACKER_STATUS_INVALID_TRACKING_POLICY:
1156                         ret_code = LTTNG_ERR_PROCESS_ATTR_TRACKER_INVALID_TRACKING_POLICY;
1157                         break;
1158                 case PROCESS_ATTR_TRACKER_STATUS_ERROR:
1159                 default:
1160                         ret_code = LTTNG_ERR_UNK;
1161                         break;
1162                 }
1163                 goto end;
1164         }
1165
1166         DBG("User space untrack %s %d for session id %" PRIu64,
1167                         lttng_process_attr_to_string(process_attr),
1168                         integral_value, session->id);
1169
1170         ret_code = id_tracker_del_id(id_tracker, integral_value);
1171         if (ret_code != LTTNG_OK) {
1172                 goto end;
1173         }
1174         /* Add session to application */
1175         switch (process_attr) {
1176         case LTTNG_PROCESS_ATTR_VIRTUAL_PROCESS_ID:
1177                 app = ust_app_find_by_pid(integral_value);
1178                 if (app) {
1179                         should_update_apps = true;
1180                 }
1181                 break;
1182         default:
1183                 should_update_apps = true;
1184                 break;
1185         }
1186         if (should_update_apps && session->active) {
1187                 ust_app_global_update_all(session);
1188         }
1189 end:
1190         return ret_code;
1191 }
1192
1193 /*
1194  * RCU safe free context structure.
1195  */
1196 static void destroy_context_rcu(struct rcu_head *head)
1197 {
1198         struct lttng_ht_node_ulong *node =
1199                 caa_container_of(head, struct lttng_ht_node_ulong, head);
1200         struct ltt_ust_context *ctx =
1201                 caa_container_of(node, struct ltt_ust_context, node);
1202
1203         trace_ust_destroy_context(ctx);
1204 }
1205
1206 /*
1207  * Cleanup UST context hash table.
1208  */
1209 static void destroy_contexts(struct lttng_ht *ht)
1210 {
1211         int ret;
1212         struct lttng_ht_node_ulong *node;
1213         struct lttng_ht_iter iter;
1214         struct ltt_ust_context *ctx;
1215
1216         assert(ht);
1217
1218         rcu_read_lock();
1219         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
1220                 /* Remove from ordered list. */
1221                 ctx = caa_container_of(node, struct ltt_ust_context, node);
1222                 cds_list_del(&ctx->list);
1223                 /* Remove from channel's hash table. */
1224                 ret = lttng_ht_del(ht, &iter);
1225                 if (!ret) {
1226                         call_rcu(&node->head, destroy_context_rcu);
1227                 }
1228         }
1229         rcu_read_unlock();
1230
1231         ht_cleanup_push(ht);
1232 }
1233
1234 /*
1235  * Cleanup ust event structure.
1236  */
1237 void trace_ust_destroy_event(struct ltt_ust_event *event)
1238 {
1239         assert(event);
1240
1241         DBG2("Trace destroy UST event %s", event->attr.name);
1242         free(event->filter_expression);
1243         free(event->filter);
1244         free(event->exclusion);
1245         free(event);
1246 }
1247
1248 /*
1249  * Cleanup ust context structure.
1250  */
1251 void trace_ust_destroy_context(struct ltt_ust_context *ctx)
1252 {
1253         assert(ctx);
1254
1255         if (ctx->ctx.ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1256                 free(ctx->ctx.u.app_ctx.provider_name);
1257                 free(ctx->ctx.u.app_ctx.ctx_name);
1258         }
1259         free(ctx);
1260 }
1261
1262 /*
1263  * URCU intermediate call to complete destroy event.
1264  */
1265 static void destroy_event_rcu(struct rcu_head *head)
1266 {
1267         struct lttng_ht_node_str *node =
1268                 caa_container_of(head, struct lttng_ht_node_str, head);
1269         struct ltt_ust_event *event =
1270                 caa_container_of(node, struct ltt_ust_event, node);
1271
1272         trace_ust_destroy_event(event);
1273 }
1274
1275 /*
1276  * Cleanup UST events hashtable.
1277  */
1278 static void destroy_events(struct lttng_ht *events)
1279 {
1280         int ret;
1281         struct lttng_ht_node_str *node;
1282         struct lttng_ht_iter iter;
1283
1284         assert(events);
1285
1286         rcu_read_lock();
1287         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1288                 ret = lttng_ht_del(events, &iter);
1289                 assert(!ret);
1290                 call_rcu(&node->head, destroy_event_rcu);
1291         }
1292         rcu_read_unlock();
1293
1294         ht_cleanup_push(events);
1295 }
1296
1297 /*
1298  * Cleanup ust channel structure.
1299  *
1300  * Should _NOT_ be called with RCU read lock held.
1301  */
1302 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1303 {
1304         assert(channel);
1305
1306         DBG2("Trace destroy UST channel %s", channel->name);
1307
1308         free(channel);
1309 }
1310
1311 /*
1312  * URCU intermediate call to complete destroy channel.
1313  */
1314 static void destroy_channel_rcu(struct rcu_head *head)
1315 {
1316         struct lttng_ht_node_str *node =
1317                 caa_container_of(head, struct lttng_ht_node_str, head);
1318         struct ltt_ust_channel *channel =
1319                 caa_container_of(node, struct ltt_ust_channel, node);
1320
1321         _trace_ust_destroy_channel(channel);
1322 }
1323
1324 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1325 {
1326         /* Destroying all events of the channel */
1327         destroy_events(channel->events);
1328         /* Destroying all context of the channel */
1329         destroy_contexts(channel->ctx);
1330
1331         call_rcu(&channel->node.head, destroy_channel_rcu);
1332 }
1333
1334 /*
1335  * Remove an UST channel from a channel HT.
1336  */
1337 void trace_ust_delete_channel(struct lttng_ht *ht,
1338                 struct ltt_ust_channel *channel)
1339 {
1340         int ret;
1341         struct lttng_ht_iter iter;
1342
1343         assert(ht);
1344         assert(channel);
1345
1346         iter.iter.node = &channel->node.node;
1347         ret = lttng_ht_del(ht, &iter);
1348         assert(!ret);
1349 }
1350
1351 /*
1352  * Iterate over a hash table containing channels and cleanup safely.
1353  */
1354 static void destroy_channels(struct lttng_ht *channels)
1355 {
1356         struct lttng_ht_node_str *node;
1357         struct lttng_ht_iter iter;
1358
1359         assert(channels);
1360
1361         rcu_read_lock();
1362         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1363                 struct ltt_ust_channel *chan =
1364                         caa_container_of(node, struct ltt_ust_channel, node);
1365
1366                 trace_ust_delete_channel(channels, chan);
1367                 trace_ust_destroy_channel(chan);
1368         }
1369         rcu_read_unlock();
1370
1371         ht_cleanup_push(channels);
1372 }
1373
1374 /*
1375  * Cleanup UST global domain.
1376  */
1377 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1378 {
1379         assert(dom);
1380
1381         destroy_channels(dom->channels);
1382 }
1383
1384 /*
1385  * Cleanup ust session structure, keeping data required by
1386  * destroy notifier.
1387  *
1388  * Should *NOT* be called with RCU read-side lock held.
1389  */
1390 void trace_ust_destroy_session(struct ltt_ust_session *session)
1391 {
1392         struct agent *agt;
1393         struct buffer_reg_uid *reg, *sreg;
1394         struct lttng_ht_iter iter;
1395
1396         assert(session);
1397
1398         DBG2("Trace UST destroy session %" PRIu64, session->id);
1399
1400         /* Cleaning up UST domain */
1401         destroy_domain_global(&session->domain_global);
1402
1403         rcu_read_lock();
1404         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1405                 int ret = lttng_ht_del(session->agents, &iter);
1406
1407                 assert(!ret);
1408                 agent_destroy(agt);
1409         }
1410         rcu_read_unlock();
1411
1412         ht_cleanup_push(session->agents);
1413
1414         /* Cleanup UID buffer registry object(s). */
1415         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1416                         lnode) {
1417                 cds_list_del(&reg->lnode);
1418                 buffer_reg_uid_remove(reg);
1419                 buffer_reg_uid_destroy(reg, session->consumer);
1420         }
1421
1422         process_attr_tracker_destroy(session->tracker_vpid);
1423         process_attr_tracker_destroy(session->tracker_vuid);
1424         process_attr_tracker_destroy(session->tracker_vgid);
1425
1426         fini_id_tracker(&session->vpid_tracker);
1427         fini_id_tracker(&session->vuid_tracker);
1428         fini_id_tracker(&session->vgid_tracker);
1429         lttng_trace_chunk_put(session->current_trace_chunk);
1430 }
1431
1432 /* Free elements needed by destroy notifiers. */
1433 void trace_ust_free_session(struct ltt_ust_session *session)
1434 {
1435         consumer_output_put(session->consumer);
1436         free(session);
1437 }