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  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _LGPL_SOURCE
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <inttypes.h>
  25
  26 #include <common/common.h>
  27 #include <common/defaults.h>
  28 #include <common/trace-chunk.h>
  29
  30 #include "buffer-registry.h"
  31 #include "trace-ust.h"
  32 #include "utils.h"
  33 #include "ust-app.h"
  34 #include "agent.h"
  35
  36 /*
  37  * Match function for the events hash table lookup.
  38  *
  39  * Matches by name only. Used by the disable command.
  40  */
  41 int trace_ust_ht_match_event_by_name(struct cds_lfht_node *node,
  42                 const void *_key)
  43 {
  44         struct ltt_ust_event *event;
  45         const char *name;
  46
  47         assert(node);
  48         assert(_key);
  49
  50         event = caa_container_of(node, struct ltt_ust_event, node.node);
  51         name = _key;
  52
  53         /* Event name */
  54         if (strncmp(event->attr.name, name, sizeof(event->attr.name)) != 0) {
  55                 goto no_match;
  56         }
  57
  58         /* Match */
  59         return 1;
  60
  61 no_match:
  62         return 0;
  63 }
  64
  65 /*
  66  * Match function for the hash table lookup.
  67  *
  68  * It matches an ust event based on three attributes which are the event name,
  69  * the filter bytecode and the loglevel.
  70  */
  71 int trace_ust_ht_match_event(struct cds_lfht_node *node, const void *_key)
  72 {
  73         struct ltt_ust_event *event;
  74         const struct ltt_ust_ht_key *key;
  75         int ev_loglevel_value;
  76         int ll_match;
  77
  78         assert(node);
  79         assert(_key);
  80
  81         event = caa_container_of(node, struct ltt_ust_event, node.node);
  82         key = _key;
  83         ev_loglevel_value = event->attr.loglevel;
  84
  85         /* Match the 4 elements of the key: name, filter, loglevel, exclusions. */
  86
  87         /* Event name */
  88         if (strncmp(event->attr.name, key->name, sizeof(event->attr.name)) != 0) {
  89                 goto no_match;
  90         }
  91
  92         /* Event loglevel value and type. */
  93         ll_match = loglevels_match(event->attr.loglevel_type,
  94                 ev_loglevel_value, key->loglevel_type,
  95                 key->loglevel_value, LTTNG_UST_LOGLEVEL_ALL);
  96
  97         if (!ll_match) {
  98                 goto no_match;
  99         }
 100
 101         /* Only one of the filters is NULL, fail. */
 102         if ((key->filter && !event->filter) || (!key->filter && event->filter)) {
 103                 goto no_match;
 104         }
 105
 106         if (key->filter && event->filter) {
 107                 /* Both filters exists, check length followed by the bytecode. */
 108                 if (event->filter->len != key->filter->len ||
 109                                 memcmp(event->filter->data, key->filter->data,
 110                                         event->filter->len) != 0) {
 111                         goto no_match;
 112                 }
 113         }
 114
 115         /* If only one of the exclusions is NULL, fail. */
 116         if ((key->exclusion && !event->exclusion) || (!key->exclusion && event->exclusion)) {
 117                 goto no_match;
 118         }
 119
 120         if (key->exclusion && event->exclusion) {
 121                 size_t i;
 122
 123                 /* Check exclusion counts first. */
 124                 if (event->exclusion->count != key->exclusion->count) {
 125                         goto no_match;
 126                 }
 127
 128                 /* Compare names individually. */
 129                 for (i = 0; i < event->exclusion->count; ++i) {
 130                         size_t j;
 131                         bool found = false;
 132                         const char *name_ev =
 133                                 LTTNG_EVENT_EXCLUSION_NAME_AT(
 134                                         event->exclusion, i);
 135
 136                         /*
 137                          * Compare this exclusion name to all the key's
 138                          * exclusion names.
 139                          */
 140                         for (j = 0; j < key->exclusion->count; ++j) {
 141                                 const char *name_key =
 142                                         LTTNG_EVENT_EXCLUSION_NAME_AT(
 143                                                 key->exclusion, j);
 144
 145                                 if (!strncmp(name_ev, name_key,
 146                                                 LTTNG_SYMBOL_NAME_LEN)) {
 147                                         /* Names match! */
 148                                         found = true;
 149                                         break;
 150                                 }
 151                         }
 152
 153                         /*
 154                          * If the current exclusion name was not found amongst
 155                          * the key's exclusion names, then there's no match.
 156                          */
 157                         if (!found) {
 158                                 goto no_match;
 159                         }
 160                 }
 161         }
 162         /* Match. */
 163         return 1;
 164
 165 no_match:
 166         return 0;
 167 }
 168
 169 /*
 170  * Find the channel in the hashtable and return channel pointer. RCU read side
 171  * lock MUST be acquired before calling this.
 172  */
 173 struct ltt_ust_channel *trace_ust_find_channel_by_name(struct lttng_ht *ht,
 174                 const char *name)
 175 {
 176         struct lttng_ht_node_str *node;
 177         struct lttng_ht_iter iter;
 178
 179         /*
 180          * If we receive an empty string for channel name, it means the
 181          * default channel name is requested.
 182          */
 183         if (name[0] == '\0')
 184                 name = DEFAULT_CHANNEL_NAME;
 185
 186         lttng_ht_lookup(ht, (void *)name, &iter);
 187         node = lttng_ht_iter_get_node_str(&iter);
 188         if (node == NULL) {
 189                 goto error;
 190         }
 191
 192         DBG2("Trace UST channel %s found by name", name);
 193
 194         return caa_container_of(node, struct ltt_ust_channel, node);
 195
 196 error:
 197         DBG2("Trace UST channel %s not found by name", name);
 198         return NULL;
 199 }
 200
 201 /*
 202  * Find the event in the hashtable and return event pointer. RCU read side lock
 203  * MUST be acquired before calling this.
 204  */
 205 struct ltt_ust_event *trace_ust_find_event(struct lttng_ht *ht,
 206                 char *name, struct lttng_filter_bytecode *filter,
 207                 enum lttng_ust_loglevel_type loglevel_type, int loglevel_value,
 208                 struct lttng_event_exclusion *exclusion)
 209 {
 210         struct lttng_ht_node_str *node;
 211         struct lttng_ht_iter iter;
 212         struct ltt_ust_ht_key key;
 213
 214         assert(name);
 215         assert(ht);
 216
 217         key.name = name;
 218         key.filter = filter;
 219         key.loglevel_type = loglevel_type;
 220         key.loglevel_value = loglevel_value;
 221         key.exclusion = exclusion;
 222
 223         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 224                         trace_ust_ht_match_event, &key, &iter.iter);
 225         node = lttng_ht_iter_get_node_str(&iter);
 226         if (node == NULL) {
 227                 goto error;
 228         }
 229
 230         DBG2("Trace UST event %s found", key.name);
 231
 232         return caa_container_of(node, struct ltt_ust_event, node);
 233
 234 error:
 235         DBG2("Trace UST event %s NOT found", key.name);
 236         return NULL;
 237 }
 238
 239 /*
 240  * Lookup an agent in the session agents hash table by domain type and return
 241  * the object if found else NULL.
 242  *
 243  * RCU read side lock must be acquired before calling and only released
 244  * once the agent is no longer in scope or being used.
 245  */
 246 struct agent *trace_ust_find_agent(struct ltt_ust_session *session,
 247                 enum lttng_domain_type domain_type)
 248 {
 249         struct agent *agt = NULL;
 250         struct lttng_ht_node_u64 *node;
 251         struct lttng_ht_iter iter;
 252         uint64_t key;
 253
 254         assert(session);
 255
 256         DBG3("Trace ust agent lookup for domain %d", domain_type);
 257
 258         key = domain_type;
 259
 260         lttng_ht_lookup(session->agents, &key, &iter);
 261         node = lttng_ht_iter_get_node_u64(&iter);
 262         if (!node) {
 263                 goto end;
 264         }
 265         agt = caa_container_of(node, struct agent, node);
 266
 267 end:
 268         return agt;
 269 }
 270
 271 /*
 272  * Allocate and initialize a ust session data structure.
 273  *
 274  * Return pointer to structure or NULL.
 275  */
 276 struct ltt_ust_session *trace_ust_create_session(uint64_t session_id)
 277 {
 278         struct ltt_ust_session *lus;
 279
 280         /* Allocate a new ltt ust session */
 281         lus = zmalloc(sizeof(struct ltt_ust_session));
 282         if (lus == NULL) {
 283                 PERROR("create ust session zmalloc");
 284                 goto error;
 285         }
 286
 287         /* Init data structure */
 288         lus->id = session_id;
 289         lus->active = 0;
 290
 291         /* Set default metadata channel attribute. */
 292         lus->metadata_attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 293         lus->metadata_attr.subbuf_size = default_get_metadata_subbuf_size();
 294         lus->metadata_attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 295         lus->metadata_attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
 296         lus->metadata_attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;
 297         lus->metadata_attr.output = LTTNG_UST_MMAP;
 298
 299         /*
 300          * Default buffer type. This can be changed through an enable channel
 301          * requesting a different type. Note that this can only be changed once
 302          * during the session lifetime which is at the first enable channel and
 303          * only before start. The flag buffer_type_changed indicates the status.
 304          */
 305         lus->buffer_type = LTTNG_BUFFER_PER_UID;
 306         /* Once set to 1, the buffer_type is immutable for the session. */
 307         lus->buffer_type_changed = 0;
 308         /* Init it in case it get used after allocation. */
 309         CDS_INIT_LIST_HEAD(&lus->buffer_reg_uid_list);
 310
 311         /* Alloc UST global domain channels' HT */
 312         lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 313         /* Alloc agent hash table. */
 314         lus->agents = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 315
 316         lus->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 317         if (lus->consumer == NULL) {
 318                 goto error_consumer;
 319         }
 320
 321         DBG2("UST trace session create successful");
 322
 323         return lus;
 324
 325 error_consumer:
 326         ht_cleanup_push(lus->domain_global.channels);
 327         ht_cleanup_push(lus->agents);
 328         free(lus);
 329 error:
 330         return NULL;
 331 }
 332
 333 /*
 334  * Allocate and initialize a ust channel data structure.
 335  *
 336  * Return pointer to structure or NULL.
 337  */
 338 struct ltt_ust_channel *trace_ust_create_channel(struct lttng_channel *chan,
 339                 enum lttng_domain_type domain)
 340 {
 341         struct ltt_ust_channel *luc;
 342
 343         assert(chan);
 344
 345         luc = zmalloc(sizeof(struct ltt_ust_channel));
 346         if (luc == NULL) {
 347                 PERROR("ltt_ust_channel zmalloc");
 348                 goto error;
 349         }
 350
 351         luc->domain = domain;
 352
 353         /* Copy UST channel attributes */
 354         luc->attr.overwrite = chan->attr.overwrite;
 355         luc->attr.subbuf_size = chan->attr.subbuf_size;
 356         luc->attr.num_subbuf = chan->attr.num_subbuf;
 357         luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
 358         luc->attr.read_timer_interval = chan->attr.read_timer_interval;
 359         luc->attr.output = (enum lttng_ust_output) chan->attr.output;
 360         luc->monitor_timer_interval = ((struct lttng_channel_extended *)
 361                         chan->attr.extended.ptr)->monitor_timer_interval;
 362         luc->attr.u.s.blocking_timeout = ((struct lttng_channel_extended *)
 363                         chan->attr.extended.ptr)->blocking_timeout;
 364
 365         /* Translate to UST output enum */
 366         switch (luc->attr.output) {
 367         default:
 368                 luc->attr.output = LTTNG_UST_MMAP;
 369                 break;
 370         }
 371
 372         /*
 373          * If we receive an empty string for channel name, it means the
 374          * default channel name is requested.
 375          */
 376         if (chan->name[0] == '\0') {
 377                 strncpy(luc->name, DEFAULT_CHANNEL_NAME, sizeof(luc->name));
 378         } else {
 379                 /* Copy channel name */
 380                 strncpy(luc->name, chan->name, sizeof(luc->name));
 381         }
 382         luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 383
 384         /* Init node */
 385         lttng_ht_node_init_str(&luc->node, luc->name);
 386         CDS_INIT_LIST_HEAD(&luc->ctx_list);
 387
 388         /* Alloc hash tables */
 389         luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 390         luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 391
 392         /* On-disk circular buffer parameters */
 393         luc->tracefile_size = chan->attr.tracefile_size;
 394         luc->tracefile_count = chan->attr.tracefile_count;
 395
 396         DBG2("Trace UST channel %s created", luc->name);
 397
 398 error:
 399         return luc;
 400 }
 401
 402 /*
 403  * Validates an exclusion list.
 404  *
 405  * Returns 0 if valid, negative value if invalid.
 406  */
 407 static int validate_exclusion(struct lttng_event_exclusion *exclusion)
 408 {
 409         size_t i;
 410         int ret = 0;
 411
 412         assert(exclusion);
 413
 414         for (i = 0; i < exclusion->count; ++i) {
 415                 size_t j;
 416                 const char *name_a =
 417                         LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, i);
 418
 419                 for (j = 0; j < i; ++j) {
 420                         const char *name_b =
 421                                 LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, j);
 422
 423                         if (!strncmp(name_a, name_b, LTTNG_SYMBOL_NAME_LEN)) {
 424                                 /* Match! */
 425                                 ret = -1;
 426                                 goto end;
 427                         }
 428                 }
 429         }
 430
 431 end:
 432         return ret;
 433 }
 434
 435 /*
 436  * Allocate and initialize a ust event. Set name and event type.
 437  * We own filter_expression, filter, and exclusion.
 438  *
 439  * Return an lttng_error_code
 440  */
 441 enum lttng_error_code trace_ust_create_event(struct lttng_event *ev,
 442                 char *filter_expression,
 443                 struct lttng_filter_bytecode *filter,
 444                 struct lttng_event_exclusion *exclusion,
 445                 bool internal_event,
 446                 struct ltt_ust_event **ust_event)
 447 {
 448         struct ltt_ust_event *local_ust_event;
 449         enum lttng_error_code ret = LTTNG_OK;
 450
 451         assert(ev);
 452
 453         if (exclusion && validate_exclusion(exclusion)) {
 454                 ret = LTTNG_ERR_INVALID;
 455                 goto error;
 456         }
 457
 458         local_ust_event = zmalloc(sizeof(struct ltt_ust_event));
 459         if (local_ust_event == NULL) {
 460                 PERROR("ust event zmalloc");
 461                 ret = LTTNG_ERR_NOMEM;
 462                 goto error;
 463         }
 464
 465         local_ust_event->internal = internal_event;
 466
 467         switch (ev->type) {
 468         case LTTNG_EVENT_PROBE:
 469                 local_ust_event->attr.instrumentation = LTTNG_UST_PROBE;
 470                 break;
 471         case LTTNG_EVENT_FUNCTION:
 472                 local_ust_event->attr.instrumentation = LTTNG_UST_FUNCTION;
 473                 break;
 474         case LTTNG_EVENT_FUNCTION_ENTRY:
 475                 local_ust_event->attr.instrumentation = LTTNG_UST_FUNCTION;
 476                 break;
 477         case LTTNG_EVENT_TRACEPOINT:
 478                 local_ust_event->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 479                 break;
 480         default:
 481                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 482                 ret = LTTNG_ERR_INVALID;
 483                 goto error_free_event;
 484         }
 485
 486         /* Copy event name */
 487         strncpy(local_ust_event->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 488         local_ust_event->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 489
 490         switch (ev->loglevel_type) {
 491         case LTTNG_EVENT_LOGLEVEL_ALL:
 492                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 493                 local_ust_event->attr.loglevel = -1;    /* Force to -1 */
 494                 break;
 495         case LTTNG_EVENT_LOGLEVEL_RANGE:
 496                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 497                 local_ust_event->attr.loglevel = ev->loglevel;
 498                 break;
 499         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 500                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 501                 local_ust_event->attr.loglevel = ev->loglevel;
 502                 break;
 503         default:
 504                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 505                 ret = LTTNG_ERR_INVALID;
 506                 goto error_free_event;
 507         }
 508
 509         /* Same layout. */
 510         local_ust_event->filter_expression = filter_expression;
 511         local_ust_event->filter = filter;
 512         local_ust_event->exclusion = exclusion;
 513
 514         /* Init node */
 515         lttng_ht_node_init_str(&local_ust_event->node, local_ust_event->attr.name);
 516
 517         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 518                 local_ust_event->attr.name, local_ust_event->attr.loglevel_type,
 519                 local_ust_event->attr.loglevel);
 520
 521         *ust_event = local_ust_event;
 522
 523         return ret;
 524
 525 error_free_event:
 526         free(local_ust_event);
 527 error:
 528         free(filter_expression);
 529         free(filter);
 530         free(exclusion);
 531         return ret;
 532 }
 533
 534 static
 535 int trace_ust_context_type_event_to_ust(
 536                 enum lttng_event_context_type type)
 537 {
 538         int utype;
 539
 540         switch (type) {
 541         case LTTNG_EVENT_CONTEXT_VTID:
 542                 utype = LTTNG_UST_CONTEXT_VTID;
 543                 break;
 544         case LTTNG_EVENT_CONTEXT_VPID:
 545                 utype = LTTNG_UST_CONTEXT_VPID;
 546                 break;
 547         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 548                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 549                 break;
 550         case LTTNG_EVENT_CONTEXT_PROCNAME:
 551                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 552                 break;
 553         case LTTNG_EVENT_CONTEXT_IP:
 554                 utype = LTTNG_UST_CONTEXT_IP;
 555                 break;
 556         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 557                 if (!ustctl_has_perf_counters()) {
 558                         utype = -1;
 559                         WARN("Perf counters not implemented in UST");
 560                 } else {
 561                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 562                 }
 563                 break;
 564         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
 565                 utype = LTTNG_UST_CONTEXT_APP_CONTEXT;
 566                 break;
 567         case LTTNG_EVENT_CONTEXT_CGROUP_NS:
 568                 utype = LTTNG_UST_CONTEXT_CGROUP_NS;
 569                 break;
 570         case LTTNG_EVENT_CONTEXT_IPC_NS:
 571                 utype = LTTNG_UST_CONTEXT_IPC_NS;
 572                 break;
 573         case LTTNG_EVENT_CONTEXT_MNT_NS:
 574                 utype = LTTNG_UST_CONTEXT_MNT_NS;
 575                 break;
 576         case LTTNG_EVENT_CONTEXT_NET_NS:
 577                 utype = LTTNG_UST_CONTEXT_NET_NS;
 578                 break;
 579         case LTTNG_EVENT_CONTEXT_PID_NS:
 580                 utype = LTTNG_UST_CONTEXT_PID_NS;
 581                 break;
 582         case LTTNG_EVENT_CONTEXT_USER_NS:
 583                 utype = LTTNG_UST_CONTEXT_USER_NS;
 584                 break;
 585         case LTTNG_EVENT_CONTEXT_UTS_NS:
 586                 utype = LTTNG_UST_CONTEXT_UTS_NS;
 587                 break;
 588         default:
 589                 utype = -1;
 590                 break;
 591         }
 592         return utype;
 593 }
 594
 595 /*
 596  * Return 1 if contexts match, 0 otherwise.
 597  */
 598 int trace_ust_match_context(const struct ltt_ust_context *uctx,
 599                 const struct lttng_event_context *ctx)
 600 {
 601         int utype;
 602
 603         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 604         if (utype < 0) {
 605                 return 0;
 606         }
 607         if (uctx->ctx.ctx != utype) {
 608                 return 0;
 609         }
 610         switch (utype) {
 611         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 612                 if (uctx->ctx.u.perf_counter.type
 613                                 != ctx->u.perf_counter.type) {
 614                         return 0;
 615                 }
 616                 if (uctx->ctx.u.perf_counter.config
 617                                 != ctx->u.perf_counter.config) {
 618                         return 0;
 619                 }
 620                 if (strncmp(uctx->ctx.u.perf_counter.name,
 621                                 ctx->u.perf_counter.name,
 622                                 LTTNG_UST_SYM_NAME_LEN)) {
 623                         return 0;
 624                 }
 625                 break;
 626         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 627                 assert(uctx->ctx.u.app_ctx.provider_name);
 628                 assert(uctx->ctx.u.app_ctx.ctx_name);
 629                 if (strcmp(uctx->ctx.u.app_ctx.provider_name,
 630                                 ctx->u.app_ctx.provider_name) ||
 631                                 strcmp(uctx->ctx.u.app_ctx.ctx_name,
 632                                 ctx->u.app_ctx.ctx_name)) {
 633                         return 0;
 634                 }
 635         default:
 636                 break;
 637
 638         }
 639         return 1;
 640 }
 641
 642 /*
 643  * Allocate and initialize an UST context.
 644  *
 645  * Return pointer to structure or NULL.
 646  */
 647 struct ltt_ust_context *trace_ust_create_context(
 648                 const struct lttng_event_context *ctx)
 649 {
 650         struct ltt_ust_context *uctx = NULL;
 651         int utype;
 652
 653         assert(ctx);
 654
 655         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 656         if (utype < 0) {
 657                 ERR("Invalid UST context");
 658                 goto end;
 659         }
 660
 661         uctx = zmalloc(sizeof(struct ltt_ust_context));
 662         if (!uctx) {
 663                 PERROR("zmalloc ltt_ust_context");
 664                 goto end;
 665         }
 666
 667         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 668         switch (utype) {
 669         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 670                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 671                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 672                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 673                                 LTTNG_UST_SYM_NAME_LEN);
 674                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 675                 break;
 676         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 677         {
 678                 char *provider_name = NULL, *ctx_name = NULL;
 679
 680                 provider_name = strdup(ctx->u.app_ctx.provider_name);
 681                 if (!provider_name) {
 682                         goto error;
 683                 }
 684                 uctx->ctx.u.app_ctx.provider_name = provider_name;
 685
 686                 ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 687                 if (!ctx_name) {
 688                         goto error;
 689                 }
 690                 uctx->ctx.u.app_ctx.ctx_name = ctx_name;
 691                 break;
 692         }
 693         default:
 694                 break;
 695         }
 696         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 697 end:
 698         return uctx;
 699 error:
 700         trace_ust_destroy_context(uctx);
 701         return NULL;
 702 }
 703
 704 static
 705 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 706 {
 707         struct ust_pid_tracker_node *tracker_node =
 708                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 709         free(tracker_node);
 710 }
 711
 712 static
 713 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 714 {
 715
 716         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 717 }
 718
 719 static
 720 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 721 {
 722         int ret = 0;
 723
 724         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 725         if (!pid_tracker->ht) {
 726                 ret = -1;
 727                 goto end;
 728         }
 729
 730 end:
 731         return ret;
 732 }
 733
 734 /*
 735  * Teardown pid tracker content, but don't free pid_tracker object.
 736  */
 737 static
 738 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 739 {
 740         struct ust_pid_tracker_node *tracker_node;
 741         struct lttng_ht_iter iter;
 742
 743         if (!pid_tracker->ht) {
 744                 return;
 745         }
 746         rcu_read_lock();
 747         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 748                         &iter.iter, tracker_node, node.node) {
 749                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 750
 751                 assert(!ret);
 752                 destroy_pid_tracker_node(tracker_node);
 753         }
 754         rcu_read_unlock();
 755         ht_cleanup_push(pid_tracker->ht);
 756         pid_tracker->ht = NULL;
 757 }
 758
 759 static
 760 struct ust_pid_tracker_node *pid_tracker_lookup(
 761                 struct ust_pid_tracker *pid_tracker, int pid,
 762                 struct lttng_ht_iter *iter)
 763 {
 764         unsigned long _pid = (unsigned long) pid;
 765         struct lttng_ht_node_ulong *node;
 766
 767         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 768         node = lttng_ht_iter_get_node_ulong(iter);
 769         if (node) {
 770                 return caa_container_of(node, struct ust_pid_tracker_node,
 771                         node);
 772         } else {
 773                 return NULL;
 774         }
 775 }
 776
 777 static
 778 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 779 {
 780         int retval = LTTNG_OK;
 781         struct ust_pid_tracker_node *tracker_node;
 782         struct lttng_ht_iter iter;
 783
 784         if (pid < 0) {
 785                 retval = LTTNG_ERR_INVALID;
 786                 goto end;
 787         }
 788         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 789         if (tracker_node) {
 790                 /* Already exists. */
 791                 retval = LTTNG_ERR_PID_TRACKED;
 792                 goto end;
 793         }
 794         tracker_node = zmalloc(sizeof(*tracker_node));
 795         if (!tracker_node) {
 796                 retval = LTTNG_ERR_NOMEM;
 797                 goto end;
 798         }
 799         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 800         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 801 end:
 802         return retval;
 803 }
 804
 805 static
 806 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 807 {
 808         int retval = LTTNG_OK, ret;
 809         struct ust_pid_tracker_node *tracker_node;
 810         struct lttng_ht_iter iter;
 811
 812         if (pid < 0) {
 813                 retval = LTTNG_ERR_INVALID;
 814                 goto end;
 815         }
 816         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 817         if (!tracker_node) {
 818                 /* Not found */
 819                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 820                 goto end;
 821         }
 822         ret = lttng_ht_del(pid_tracker->ht, &iter);
 823         assert(!ret);
 824
 825         destroy_pid_tracker_node(tracker_node);
 826 end:
 827         return retval;
 828 }
 829
 830 /*
 831  * The session lock is held when calling this function.
 832  */
 833 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 834 {
 835         struct lttng_ht_iter iter;
 836
 837         if (!session->pid_tracker.ht) {
 838                 return 1;
 839         }
 840         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 841                 return 1;
 842         }
 843         return 0;
 844 }
 845
 846 /*
 847  * Called with the session lock held.
 848  */
 849 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 850 {
 851         int retval = LTTNG_OK;
 852         bool should_update_apps = false;
 853
 854         if (pid == -1) {
 855                 /* Track all pids: destroy tracker if exists. */
 856                 if (session->pid_tracker.ht) {
 857                         fini_pid_tracker(&session->pid_tracker);
 858                         /* Ensure all apps have session. */
 859                         should_update_apps = true;
 860                 }
 861         } else {
 862                 int ret;
 863
 864                 if (!session->pid_tracker.ht) {
 865                         /* Create tracker. */
 866                         if (init_pid_tracker(&session->pid_tracker)) {
 867                                 ERR("Error initializing PID tracker");
 868                                 retval = LTTNG_ERR_NOMEM;
 869                                 goto end;
 870                         }
 871                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 872                         if (ret != LTTNG_OK) {
 873                                 retval = ret;
 874                                 fini_pid_tracker(&session->pid_tracker);
 875                                 goto end;
 876                         }
 877                         /* Remove all apps from session except pid. */
 878                         should_update_apps = true;
 879                 } else {
 880                         struct ust_app *app;
 881
 882                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 883                         if (ret != LTTNG_OK) {
 884                                 retval = ret;
 885                                 goto end;
 886                         }
 887                         /* Add session to application */
 888                         app = ust_app_find_by_pid(pid);
 889                         if (app) {
 890                                 should_update_apps = true;
 891                         }
 892                 }
 893         }
 894         if (should_update_apps && session->active) {
 895                 ust_app_global_update_all(session);
 896         }
 897 end:
 898         return retval;
 899 }
 900
 901 /*
 902  * Called with the session lock held.
 903  */
 904 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 905 {
 906         int retval = LTTNG_OK;
 907
 908         if (pid == -1) {
 909                 /* Create empty tracker, replace old tracker. */
 910                 struct ust_pid_tracker tmp_tracker;
 911
 912                 tmp_tracker = session->pid_tracker;
 913                 if (init_pid_tracker(&session->pid_tracker)) {
 914                         ERR("Error initializing PID tracker");
 915                         retval = LTTNG_ERR_NOMEM;
 916                         /* Rollback operation. */
 917                         session->pid_tracker = tmp_tracker;
 918                         goto end;
 919                 }
 920                 fini_pid_tracker(&tmp_tracker);
 921
 922                 /* Remove session from all applications */
 923                 ust_app_global_update_all(session);
 924         } else {
 925                 int ret;
 926                 struct ust_app *app;
 927
 928                 if (!session->pid_tracker.ht) {
 929                         /* No PID being tracked. */
 930                         retval = LTTNG_ERR_PID_NOT_TRACKED;
 931                         goto end;
 932                 }
 933                 /* Remove PID from tracker */
 934                 ret = pid_tracker_del_pid(&session->pid_tracker, pid);
 935                 if (ret != LTTNG_OK) {
 936                         retval = ret;
 937                         goto end;
 938                 }
 939                 /* Remove session from application. */
 940                 app = ust_app_find_by_pid(pid);
 941                 if (app) {
 942                         ust_app_global_update(session, app);
 943                 }
 944         }
 945 end:
 946         return retval;
 947 }
 948
 949 /*
 950  * Called with session lock held.
 951  */
 952 ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
 953                 int32_t **_pids)
 954 {
 955         struct ust_pid_tracker_node *tracker_node;
 956         struct lttng_ht_iter iter;
 957         unsigned long count, i = 0;
 958         long approx[2];
 959         int32_t *pids;
 960         int ret = 0;
 961
 962         if (!session->pid_tracker.ht) {
 963                 /* Tracker disabled. Set first entry to -1. */
 964                 pids = zmalloc(sizeof(*pids));
 965                 if (!pids) {
 966                         ret = -1;
 967                         goto end;
 968                 }
 969                 pids[0] = -1;
 970                 *_pids = pids;
 971                 return 1;
 972         }
 973
 974         rcu_read_lock();
 975         cds_lfht_count_nodes(session->pid_tracker.ht->ht,
 976                 &approx[0], &count, &approx[1]);
 977         pids = zmalloc(sizeof(*pids) * count);
 978         if (!pids) {
 979                 ret = -1;
 980                 goto end;
 981         }
 982         cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
 983                         &iter.iter, tracker_node, node.node) {
 984                 pids[i++] = tracker_node->node.key;
 985         }
 986         *_pids = pids;
 987         ret = count;
 988 end:
 989         rcu_read_unlock();
 990         return ret;
 991 }
 992
 993 /*
 994  * RCU safe free context structure.
 995  */
 996 static void destroy_context_rcu(struct rcu_head *head)
 997 {
 998         struct lttng_ht_node_ulong *node =
 999                 caa_container_of(head, struct lttng_ht_node_ulong, head);
1000         struct ltt_ust_context *ctx =
1001                 caa_container_of(node, struct ltt_ust_context, node);
1002
1003         trace_ust_destroy_context(ctx);
1004 }
1005
1006 /*
1007  * Cleanup UST context hash table.
1008  */
1009 static void destroy_contexts(struct lttng_ht *ht)
1010 {
1011         int ret;
1012         struct lttng_ht_node_ulong *node;
1013         struct lttng_ht_iter iter;
1014         struct ltt_ust_context *ctx;
1015
1016         assert(ht);
1017
1018         rcu_read_lock();
1019         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
1020                 /* Remove from ordered list. */
1021                 ctx = caa_container_of(node, struct ltt_ust_context, node);
1022                 cds_list_del(&ctx->list);
1023                 /* Remove from channel's hash table. */
1024                 ret = lttng_ht_del(ht, &iter);
1025                 if (!ret) {
1026                         call_rcu(&node->head, destroy_context_rcu);
1027                 }
1028         }
1029         rcu_read_unlock();
1030
1031         ht_cleanup_push(ht);
1032 }
1033
1034 /*
1035  * Cleanup ust event structure.
1036  */
1037 void trace_ust_destroy_event(struct ltt_ust_event *event)
1038 {
1039         assert(event);
1040
1041         DBG2("Trace destroy UST event %s", event->attr.name);
1042         free(event->filter_expression);
1043         free(event->filter);
1044         free(event->exclusion);
1045         free(event);
1046 }
1047
1048 /*
1049  * Cleanup ust context structure.
1050  */
1051 void trace_ust_destroy_context(struct ltt_ust_context *ctx)
1052 {
1053         assert(ctx);
1054
1055         if (ctx->ctx.ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1056                 free(ctx->ctx.u.app_ctx.provider_name);
1057                 free(ctx->ctx.u.app_ctx.ctx_name);
1058         }
1059         free(ctx);
1060 }
1061
1062 /*
1063  * URCU intermediate call to complete destroy event.
1064  */
1065 static void destroy_event_rcu(struct rcu_head *head)
1066 {
1067         struct lttng_ht_node_str *node =
1068                 caa_container_of(head, struct lttng_ht_node_str, head);
1069         struct ltt_ust_event *event =
1070                 caa_container_of(node, struct ltt_ust_event, node);
1071
1072         trace_ust_destroy_event(event);
1073 }
1074
1075 /*
1076  * Cleanup UST events hashtable.
1077  */
1078 static void destroy_events(struct lttng_ht *events)
1079 {
1080         int ret;
1081         struct lttng_ht_node_str *node;
1082         struct lttng_ht_iter iter;
1083
1084         assert(events);
1085
1086         rcu_read_lock();
1087         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1088                 ret = lttng_ht_del(events, &iter);
1089                 assert(!ret);
1090                 call_rcu(&node->head, destroy_event_rcu);
1091         }
1092         rcu_read_unlock();
1093
1094         ht_cleanup_push(events);
1095 }
1096
1097 /*
1098  * Cleanup ust channel structure.
1099  *
1100  * Should _NOT_ be called with RCU read lock held.
1101  */
1102 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1103 {
1104         assert(channel);
1105
1106         DBG2("Trace destroy UST channel %s", channel->name);
1107
1108         free(channel);
1109 }
1110
1111 /*
1112  * URCU intermediate call to complete destroy channel.
1113  */
1114 static void destroy_channel_rcu(struct rcu_head *head)
1115 {
1116         struct lttng_ht_node_str *node =
1117                 caa_container_of(head, struct lttng_ht_node_str, head);
1118         struct ltt_ust_channel *channel =
1119                 caa_container_of(node, struct ltt_ust_channel, node);
1120
1121         _trace_ust_destroy_channel(channel);
1122 }
1123
1124 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1125 {
1126         /* Destroying all events of the channel */
1127         destroy_events(channel->events);
1128         /* Destroying all context of the channel */
1129         destroy_contexts(channel->ctx);
1130
1131         call_rcu(&channel->node.head, destroy_channel_rcu);
1132 }
1133
1134 /*
1135  * Remove an UST channel from a channel HT.
1136  */
1137 void trace_ust_delete_channel(struct lttng_ht *ht,
1138                 struct ltt_ust_channel *channel)
1139 {
1140         int ret;
1141         struct lttng_ht_iter iter;
1142
1143         assert(ht);
1144         assert(channel);
1145
1146         iter.iter.node = &channel->node.node;
1147         ret = lttng_ht_del(ht, &iter);
1148         assert(!ret);
1149 }
1150
1151 /*
1152  * Iterate over a hash table containing channels and cleanup safely.
1153  */
1154 static void destroy_channels(struct lttng_ht *channels)
1155 {
1156         struct lttng_ht_node_str *node;
1157         struct lttng_ht_iter iter;
1158
1159         assert(channels);
1160
1161         rcu_read_lock();
1162         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1163                 struct ltt_ust_channel *chan =
1164                         caa_container_of(node, struct ltt_ust_channel, node);
1165
1166                 trace_ust_delete_channel(channels, chan);
1167                 trace_ust_destroy_channel(chan);
1168         }
1169         rcu_read_unlock();
1170
1171         ht_cleanup_push(channels);
1172 }
1173
1174 /*
1175  * Cleanup UST global domain.
1176  */
1177 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1178 {
1179         assert(dom);
1180
1181         destroy_channels(dom->channels);
1182 }
1183
1184 /*
1185  * Cleanup ust session structure, keeping data required by
1186  * destroy notifier.
1187  *
1188  * Should *NOT* be called with RCU read-side lock held.
1189  */
1190 void trace_ust_destroy_session(struct ltt_ust_session *session)
1191 {
1192         struct agent *agt;
1193         struct buffer_reg_uid *reg, *sreg;
1194         struct lttng_ht_iter iter;
1195
1196         assert(session);
1197
1198         DBG2("Trace UST destroy session %" PRIu64, session->id);
1199
1200         /* Cleaning up UST domain */
1201         destroy_domain_global(&session->domain_global);
1202
1203         rcu_read_lock();
1204         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1205                 int ret = lttng_ht_del(session->agents, &iter);
1206
1207                 assert(!ret);
1208                 agent_destroy(agt);
1209         }
1210         rcu_read_unlock();
1211
1212         ht_cleanup_push(session->agents);
1213
1214         /* Cleanup UID buffer registry object(s). */
1215         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1216                         lnode) {
1217                 cds_list_del(&reg->lnode);
1218                 buffer_reg_uid_remove(reg);
1219                 buffer_reg_uid_destroy(reg, session->consumer);
1220         }
1221
1222         fini_pid_tracker(&session->pid_tracker);
1223         lttng_trace_chunk_put(session->current_trace_chunk);
1224 }
1225
1226 /* Free elements needed by destroy notifiers. */
1227 void trace_ust_free_session(struct ltt_ust_session *session)
1228 {
1229         consumer_output_put(session->consumer);
1230         free(session);
1231 }