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

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <unistd.h>
  23 #include <inttypes.h>
  24
  25 #include <common/common.h>
  26 #include <common/defaults.h>
  27
  28 #include "buffer-registry.h"
  29 #include "trace-ust.h"
  30 #include "utils.h"
  31 #include "ust-app.h"
  32 #include "agent.h"
  33
  34 /*
  35  * Match function for the events hash table lookup.
  36  *
  37  * Matches by name only. Used by the disable command.
  38  */
  39 int trace_ust_ht_match_event_by_name(struct cds_lfht_node *node,
  40                 const void *_key)
  41 {
  42         struct ltt_ust_event *event;
  43         const char *name;
  44
  45         assert(node);
  46         assert(_key);
  47
  48         event = caa_container_of(node, struct ltt_ust_event, node.node);
  49         name = _key;
  50
  51         /* Event name */
  52         if (strncmp(event->attr.name, name, sizeof(event->attr.name)) != 0) {
  53                 goto no_match;
  54         }
  55
  56         /* Match */
  57         return 1;
  58
  59 no_match:
  60         return 0;
  61 }
  62
  63 /*
  64  * Match function for the hash table lookup.
  65  *
  66  * It matches an ust event based on three attributes which are the event name,
  67  * the filter bytecode and the loglevel.
  68  */
  69 int trace_ust_ht_match_event(struct cds_lfht_node *node, const void *_key)
  70 {
  71         struct ltt_ust_event *event;
  72         const struct ltt_ust_ht_key *key;
  73         int ev_loglevel_value;
  74         int ll_match;
  75
  76         assert(node);
  77         assert(_key);
  78
  79         event = caa_container_of(node, struct ltt_ust_event, node.node);
  80         key = _key;
  81         ev_loglevel_value = event->attr.loglevel;
  82
  83         /* Match the 4 elements of the key: name, filter, loglevel, exclusions. */
  84
  85         /* Event name */
  86         if (strncmp(event->attr.name, key->name, sizeof(event->attr.name)) != 0) {
  87                 goto no_match;
  88         }
  89
  90         /* Event loglevel value and type. */
  91         ll_match = loglevels_match(event->attr.loglevel_type,
  92                 ev_loglevel_value, key->loglevel_type,
  93                 key->loglevel_value, LTTNG_UST_LOGLEVEL_ALL);
  94
  95         if (!ll_match) {
  96                 goto no_match;
  97         }
  98
  99         /* Only one of the filters is NULL, fail. */
 100         if ((key->filter && !event->filter) || (!key->filter && event->filter)) {
 101                 goto no_match;
 102         }
 103
 104         if (key->filter && event->filter) {
 105                 /* Both filters exists, check length followed by the bytecode. */
 106                 if (event->filter->len != key->filter->len ||
 107                                 memcmp(event->filter->data, key->filter->data,
 108                                         event->filter->len) != 0) {
 109                         goto no_match;
 110                 }
 111         }
 112
 113         /* If only one of the exclusions is NULL, fail. */
 114         if ((key->exclusion && !event->exclusion) || (!key->exclusion && event->exclusion)) {
 115                 goto no_match;
 116         }
 117
 118         if (key->exclusion && event->exclusion) {
 119                 size_t i;
 120
 121                 /* Check exclusion counts first. */
 122                 if (event->exclusion->count != key->exclusion->count) {
 123                         goto no_match;
 124                 }
 125
 126                 /* Compare names individually. */
 127                 for (i = 0; i < event->exclusion->count; ++i) {
 128                         size_t j;
 129                         bool found = false;
 130                         const char *name_ev =
 131                                 LTTNG_EVENT_EXCLUSION_NAME_AT(
 132                                         event->exclusion, i);
 133
 134                         /*
 135                          * Compare this exclusion name to all the key's
 136                          * exclusion names.
 137                          */
 138                         for (j = 0; j < key->exclusion->count; ++j) {
 139                                 const char *name_key =
 140                                         LTTNG_EVENT_EXCLUSION_NAME_AT(
 141                                                 key->exclusion, j);
 142
 143                                 if (!strncmp(name_ev, name_key,
 144                                                 LTTNG_SYMBOL_NAME_LEN)) {
 145                                         /* Names match! */
 146                                         found = true;
 147                                         break;
 148                                 }
 149                         }
 150
 151                         /*
 152                          * If the current exclusion name was not found amongst
 153                          * the key's exclusion names, then there's no match.
 154                          */
 155                         if (!found) {
 156                                 goto no_match;
 157                         }
 158                 }
 159         }
 160         /* Match. */
 161         return 1;
 162
 163 no_match:
 164         return 0;
 165 }
 166
 167 /*
 168  * Find the channel in the hashtable and return channel pointer. RCU read side
 169  * lock MUST be acquired before calling this.
 170  */
 171 struct ltt_ust_channel *trace_ust_find_channel_by_name(struct lttng_ht *ht,
 172                 char *name)
 173 {
 174         struct lttng_ht_node_str *node;
 175         struct lttng_ht_iter iter;
 176
 177         /*
 178          * If we receive an empty string for channel name, it means the
 179          * default channel name is requested.
 180          */
 181         if (name[0] == '\0')
 182                 name = DEFAULT_CHANNEL_NAME;
 183
 184         lttng_ht_lookup(ht, (void *)name, &iter);
 185         node = lttng_ht_iter_get_node_str(&iter);
 186         if (node == NULL) {
 187                 goto error;
 188         }
 189
 190         DBG2("Trace UST channel %s found by name", name);
 191
 192         return caa_container_of(node, struct ltt_ust_channel, node);
 193
 194 error:
 195         DBG2("Trace UST channel %s not found by name", name);
 196         return NULL;
 197 }
 198
 199 /*
 200  * Find the event in the hashtable and return event pointer. RCU read side lock
 201  * MUST be acquired before calling this.
 202  */
 203 struct ltt_ust_event *trace_ust_find_event(struct lttng_ht *ht,
 204                 char *name, struct lttng_filter_bytecode *filter,
 205                 enum lttng_ust_loglevel_type loglevel_type, int loglevel_value,
 206                 struct lttng_event_exclusion *exclusion)
 207 {
 208         struct lttng_ht_node_str *node;
 209         struct lttng_ht_iter iter;
 210         struct ltt_ust_ht_key key;
 211
 212         assert(name);
 213         assert(ht);
 214
 215         key.name = name;
 216         key.filter = filter;
 217         key.loglevel_type = loglevel_type;
 218         key.loglevel_value = loglevel_value;
 219         key.exclusion = exclusion;
 220
 221         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 222                         trace_ust_ht_match_event, &key, &iter.iter);
 223         node = lttng_ht_iter_get_node_str(&iter);
 224         if (node == NULL) {
 225                 goto error;
 226         }
 227
 228         DBG2("Trace UST event %s found", key.name);
 229
 230         return caa_container_of(node, struct ltt_ust_event, node);
 231
 232 error:
 233         DBG2("Trace UST event %s NOT found", key.name);
 234         return NULL;
 235 }
 236
 237 /*
 238  * Lookup an agent in the session agents hash table by domain type and return
 239  * the object if found else NULL.
 240  *
 241  * RCU read side lock must be acquired before calling and only released
 242  * once the agent is no longer in scope or being used.
 243  */
 244 struct agent *trace_ust_find_agent(struct ltt_ust_session *session,
 245                 enum lttng_domain_type domain_type)
 246 {
 247         struct agent *agt = NULL;
 248         struct lttng_ht_node_u64 *node;
 249         struct lttng_ht_iter iter;
 250         uint64_t key;
 251
 252         assert(session);
 253
 254         DBG3("Trace ust agent lookup for domain %d", domain_type);
 255
 256         key = domain_type;
 257
 258         lttng_ht_lookup(session->agents, &key, &iter);
 259         node = lttng_ht_iter_get_node_u64(&iter);
 260         if (!node) {
 261                 goto end;
 262         }
 263         agt = caa_container_of(node, struct agent, node);
 264
 265 end:
 266         return agt;
 267 }
 268
 269 /*
 270  * Allocate and initialize a ust session data structure.
 271  *
 272  * Return pointer to structure or NULL.
 273  */
 274 struct ltt_ust_session *trace_ust_create_session(uint64_t session_id)
 275 {
 276         struct ltt_ust_session *lus;
 277
 278         /* Allocate a new ltt ust session */
 279         lus = zmalloc(sizeof(struct ltt_ust_session));
 280         if (lus == NULL) {
 281                 PERROR("create ust session zmalloc");
 282                 goto error;
 283         }
 284
 285         /* Init data structure */
 286         lus->id = session_id;
 287         lus->active = 0;
 288
 289         /* Set default metadata channel attribute. */
 290         lus->metadata_attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 291         lus->metadata_attr.subbuf_size = default_get_metadata_subbuf_size();
 292         lus->metadata_attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 293         lus->metadata_attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
 294         lus->metadata_attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;
 295         lus->metadata_attr.output = LTTNG_UST_MMAP;
 296
 297         /*
 298          * Default buffer type. This can be changed through an enable channel
 299          * requesting a different type. Note that this can only be changed once
 300          * during the session lifetime which is at the first enable channel and
 301          * only before start. The flag buffer_type_changed indicates the status.
 302          */
 303         lus->buffer_type = LTTNG_BUFFER_PER_UID;
 304         /* Once set to 1, the buffer_type is immutable for the session. */
 305         lus->buffer_type_changed = 0;
 306         /* Init it in case it get used after allocation. */
 307         CDS_INIT_LIST_HEAD(&lus->buffer_reg_uid_list);
 308
 309         /* Alloc UST global domain channels' HT */
 310         lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 311         /* Alloc agent hash table. */
 312         lus->agents = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 313
 314         lus->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 315         if (lus->consumer == NULL) {
 316                 goto error_consumer;
 317         }
 318
 319         DBG2("UST trace session create successful");
 320
 321         return lus;
 322
 323 error_consumer:
 324         ht_cleanup_push(lus->domain_global.channels);
 325         ht_cleanup_push(lus->agents);
 326         free(lus);
 327 error:
 328         return NULL;
 329 }
 330
 331 /*
 332  * Allocate and initialize a ust channel data structure.
 333  *
 334  * Return pointer to structure or NULL.
 335  */
 336 struct ltt_ust_channel *trace_ust_create_channel(struct lttng_channel *chan,
 337                 enum lttng_domain_type domain)
 338 {
 339         struct ltt_ust_channel *luc;
 340
 341         assert(chan);
 342
 343         luc = zmalloc(sizeof(struct ltt_ust_channel));
 344         if (luc == NULL) {
 345                 PERROR("ltt_ust_channel zmalloc");
 346                 goto error;
 347         }
 348
 349         luc->domain = domain;
 350
 351         /* Copy UST channel attributes */
 352         luc->attr.overwrite = chan->attr.overwrite;
 353         luc->attr.subbuf_size = chan->attr.subbuf_size;
 354         luc->attr.num_subbuf = chan->attr.num_subbuf;
 355         luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
 356         luc->attr.read_timer_interval = chan->attr.read_timer_interval;
 357         luc->attr.output = (enum lttng_ust_output) chan->attr.output;
 358
 359         /* Translate to UST output enum */
 360         switch (luc->attr.output) {
 361         default:
 362                 luc->attr.output = LTTNG_UST_MMAP;
 363                 break;
 364         }
 365
 366         /*
 367          * If we receive an empty string for channel name, it means the
 368          * default channel name is requested.
 369          */
 370         if (chan->name[0] == '\0') {
 371                 strncpy(luc->name, DEFAULT_CHANNEL_NAME, sizeof(luc->name));
 372         } else {
 373                 /* Copy channel name */
 374                 strncpy(luc->name, chan->name, sizeof(luc->name));
 375         }
 376         luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 377
 378         /* Init node */
 379         lttng_ht_node_init_str(&luc->node, luc->name);
 380         CDS_INIT_LIST_HEAD(&luc->ctx_list);
 381
 382         /* Alloc hash tables */
 383         luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 384         luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 385
 386         /* On-disk circular buffer parameters */
 387         luc->tracefile_size = chan->attr.tracefile_size;
 388         luc->tracefile_count = chan->attr.tracefile_count;
 389
 390         DBG2("Trace UST channel %s created", luc->name);
 391
 392 error:
 393         return luc;
 394 }
 395
 396 /*
 397  * Validates an exclusion list.
 398  *
 399  * Returns 0 if valid, negative value if invalid.
 400  */
 401 static int validate_exclusion(struct lttng_event_exclusion *exclusion)
 402 {
 403         size_t i;
 404         int ret = 0;
 405
 406         assert(exclusion);
 407
 408         for (i = 0; i < exclusion->count; ++i) {
 409                 size_t j;
 410                 const char *name_a =
 411                         LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, i);
 412
 413                 for (j = 0; j < i; ++j) {
 414                         const char *name_b =
 415                                 LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, j);
 416
 417                         if (!strncmp(name_a, name_b, LTTNG_SYMBOL_NAME_LEN)) {
 418                                 /* Match! */
 419                                 ret = -1;
 420                                 goto end;
 421                         }
 422                 }
 423         }
 424
 425 end:
 426         return ret;
 427 }
 428
 429 /*
 430  * Allocate and initialize a ust event. Set name and event type.
 431  * We own filter_expression, filter, and exclusion.
 432  *
 433  * Return pointer to structure or NULL.
 434  */
 435 struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev,
 436                 char *filter_expression,
 437                 struct lttng_filter_bytecode *filter,
 438                 struct lttng_event_exclusion *exclusion,
 439                 bool internal_event)
 440 {
 441         struct ltt_ust_event *lue;
 442
 443         assert(ev);
 444
 445         if (exclusion && validate_exclusion(exclusion)) {
 446                 goto error;
 447         }
 448
 449         lue = zmalloc(sizeof(struct ltt_ust_event));
 450         if (lue == NULL) {
 451                 PERROR("ust event zmalloc");
 452                 goto error;
 453         }
 454
 455         lue->internal = internal_event;
 456
 457         switch (ev->type) {
 458         case LTTNG_EVENT_PROBE:
 459                 lue->attr.instrumentation = LTTNG_UST_PROBE;
 460                 break;
 461         case LTTNG_EVENT_FUNCTION:
 462                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 463                 break;
 464         case LTTNG_EVENT_FUNCTION_ENTRY:
 465                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 466                 break;
 467         case LTTNG_EVENT_TRACEPOINT:
 468                 lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 469                 break;
 470         default:
 471                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 472                 goto error_free_event;
 473         }
 474
 475         /* Copy event name */
 476         strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 477         lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 478
 479         switch (ev->loglevel_type) {
 480         case LTTNG_EVENT_LOGLEVEL_ALL:
 481                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 482                 lue->attr.loglevel = -1;        /* Force to -1 */
 483                 break;
 484         case LTTNG_EVENT_LOGLEVEL_RANGE:
 485                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 486                 lue->attr.loglevel = ev->loglevel;
 487                 break;
 488         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 489                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 490                 lue->attr.loglevel = ev->loglevel;
 491                 break;
 492         default:
 493                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 494                 goto error_free_event;
 495         }
 496
 497         /* Same layout. */
 498         lue->filter_expression = filter_expression;
 499         lue->filter = filter;
 500         lue->exclusion = exclusion;
 501
 502         /* Init node */
 503         lttng_ht_node_init_str(&lue->node, lue->attr.name);
 504
 505         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 506                 lue->attr.name, lue->attr.loglevel_type,
 507                 lue->attr.loglevel);
 508
 509         return lue;
 510
 511 error_free_event:
 512         free(lue);
 513 error:
 514         free(filter_expression);
 515         free(filter);
 516         free(exclusion);
 517         return NULL;
 518 }
 519
 520 static
 521 int trace_ust_context_type_event_to_ust(enum lttng_event_context_type type)
 522 {
 523         int utype;
 524
 525         switch (type) {
 526         case LTTNG_EVENT_CONTEXT_VTID:
 527                 utype = LTTNG_UST_CONTEXT_VTID;
 528                 break;
 529         case LTTNG_EVENT_CONTEXT_VPID:
 530                 utype = LTTNG_UST_CONTEXT_VPID;
 531                 break;
 532         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 533                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 534                 break;
 535         case LTTNG_EVENT_CONTEXT_PROCNAME:
 536                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 537                 break;
 538         case LTTNG_EVENT_CONTEXT_IP:
 539                 utype = LTTNG_UST_CONTEXT_IP;
 540                 break;
 541         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 542                 if (!ustctl_has_perf_counters()) {
 543                         utype = -1;
 544                         WARN("Perf counters not implemented in UST");
 545                 } else {
 546                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 547                 }
 548                 break;
 549         default:
 550                 ERR("Invalid UST context");
 551                 utype = -1;
 552                 break;
 553         }
 554         return utype;
 555 }
 556
 557 /*
 558  * Return 1 if contexts match, 0 otherwise.
 559  */
 560 int trace_ust_match_context(struct ltt_ust_context *uctx,
 561                 struct lttng_event_context *ctx)
 562 {
 563         int utype;
 564
 565         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 566         if (utype < 0) {
 567                 return 0;
 568         }
 569         if (uctx->ctx.ctx != utype) {
 570                 return 0;
 571         }
 572         switch (utype) {
 573         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 574                 if (uctx->ctx.u.perf_counter.type
 575                                 != ctx->u.perf_counter.type) {
 576                         return 0;
 577                 }
 578                 if (uctx->ctx.u.perf_counter.config
 579                                 != ctx->u.perf_counter.config) {
 580                         return 0;
 581                 }
 582                 if (strncmp(uctx->ctx.u.perf_counter.name,
 583                                 ctx->u.perf_counter.name,
 584                                 LTTNG_UST_SYM_NAME_LEN)) {
 585                         return 0;
 586                 }
 587                 break;
 588         default:
 589                 break;
 590
 591         }
 592         return 1;
 593 }
 594
 595 /*
 596  * Allocate and initialize an UST context.
 597  *
 598  * Return pointer to structure or NULL.
 599  */
 600 struct ltt_ust_context *trace_ust_create_context(
 601                 struct lttng_event_context *ctx)
 602 {
 603         struct ltt_ust_context *uctx;
 604         int utype;
 605
 606         assert(ctx);
 607
 608         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 609         if (utype < 0) {
 610                 return NULL;
 611         }
 612
 613         uctx = zmalloc(sizeof(struct ltt_ust_context));
 614         if (uctx == NULL) {
 615                 PERROR("zmalloc ltt_ust_context");
 616                 goto error;
 617         }
 618
 619         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 620         switch (utype) {
 621         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 622                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 623                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 624                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 625                                 LTTNG_UST_SYM_NAME_LEN);
 626                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 627                 break;
 628         default:
 629                 break;
 630         }
 631         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 632
 633         return uctx;
 634
 635 error:
 636         return NULL;
 637 }
 638
 639 static
 640 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 641 {
 642         struct ust_pid_tracker_node *tracker_node =
 643                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 644         free(tracker_node);
 645 }
 646
 647 static
 648 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 649 {
 650
 651         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 652 }
 653
 654 static
 655 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 656 {
 657         int ret = 0;
 658
 659         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 660         if (!pid_tracker->ht) {
 661                 ret = -1;
 662                 goto end;
 663         }
 664
 665 end:
 666         return ret;
 667 }
 668
 669 /*
 670  * Teardown pid tracker content, but don't free pid_tracker object.
 671  */
 672 static
 673 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 674 {
 675         struct ust_pid_tracker_node *tracker_node;
 676         struct lttng_ht_iter iter;
 677
 678         if (!pid_tracker->ht) {
 679                 return;
 680         }
 681         rcu_read_lock();
 682         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 683                         &iter.iter, tracker_node, node.node) {
 684                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 685
 686                 assert(!ret);
 687                 destroy_pid_tracker_node(tracker_node);
 688         }
 689         rcu_read_unlock();
 690         ht_cleanup_push(pid_tracker->ht);
 691         pid_tracker->ht = NULL;
 692 }
 693
 694 static
 695 struct ust_pid_tracker_node *pid_tracker_lookup(
 696                 struct ust_pid_tracker *pid_tracker, int pid,
 697                 struct lttng_ht_iter *iter)
 698 {
 699         unsigned long _pid = (unsigned long) pid;
 700         struct lttng_ht_node_ulong *node;
 701
 702         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 703         node = lttng_ht_iter_get_node_ulong(iter);
 704         if (node) {
 705                 return caa_container_of(node, struct ust_pid_tracker_node,
 706                         node);
 707         } else {
 708                 return NULL;
 709         }
 710 }
 711
 712 static
 713 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 714 {
 715         int retval = LTTNG_OK;
 716         struct ust_pid_tracker_node *tracker_node;
 717         struct lttng_ht_iter iter;
 718
 719         if (pid < 0) {
 720                 retval = LTTNG_ERR_INVALID;
 721                 goto end;
 722         }
 723         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 724         if (tracker_node) {
 725                 /* Already exists. */
 726                 retval = LTTNG_ERR_PID_TRACKED;
 727                 goto end;
 728         }
 729         tracker_node = zmalloc(sizeof(*tracker_node));
 730         if (!tracker_node) {
 731                 retval = LTTNG_ERR_NOMEM;
 732                 goto end;
 733         }
 734         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 735         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 736 end:
 737         return retval;
 738 }
 739
 740 static
 741 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 742 {
 743         int retval = LTTNG_OK, ret;
 744         struct ust_pid_tracker_node *tracker_node;
 745         struct lttng_ht_iter iter;
 746
 747         if (pid < 0) {
 748                 retval = LTTNG_ERR_INVALID;
 749                 goto end;
 750         }
 751         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 752         if (!tracker_node) {
 753                 /* Not found */
 754                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 755                 goto end;
 756         }
 757         ret = lttng_ht_del(pid_tracker->ht, &iter);
 758         assert(!ret);
 759
 760         destroy_pid_tracker_node(tracker_node);
 761 end:
 762         return retval;
 763 }
 764
 765 /*
 766  * The session lock is held when calling this function.
 767  */
 768 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 769 {
 770         struct lttng_ht_iter iter;
 771
 772         if (!session->pid_tracker.ht) {
 773                 return 1;
 774         }
 775         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 776                 return 1;
 777         }
 778         return 0;
 779 }
 780
 781 /*
 782  * Called with the session lock held.
 783  */
 784 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 785 {
 786         int retval = LTTNG_OK;
 787
 788         if (pid == -1) {
 789                 /* Track all pids: destroy tracker if exists. */
 790                 if (session->pid_tracker.ht) {
 791                         fini_pid_tracker(&session->pid_tracker);
 792                         /* Ensure all apps have session. */
 793                         ust_app_global_update_all(session);
 794                 }
 795         } else {
 796                 int ret;
 797
 798                 if (!session->pid_tracker.ht) {
 799                         /* Create tracker. */
 800                         if (init_pid_tracker(&session->pid_tracker)) {
 801                                 ERR("Error initializing PID tracker");
 802                                 retval = LTTNG_ERR_NOMEM;
 803                                 goto end;
 804                         }
 805                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 806                         if (ret != LTTNG_OK) {
 807                                 retval = ret;
 808                                 fini_pid_tracker(&session->pid_tracker);
 809                                 goto end;
 810                         }
 811                         /* Remove all apps from session except pid. */
 812                         ust_app_global_update_all(session);
 813                 } else {
 814                         struct ust_app *app;
 815
 816                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 817                         if (ret != LTTNG_OK) {
 818                                 retval = ret;
 819                                 goto end;
 820                         }
 821                         /* Add session to application */
 822                         app = ust_app_find_by_pid(pid);
 823                         if (app) {
 824                                 ust_app_global_update(session, app);
 825                         }
 826                 }
 827         }
 828 end:
 829         return retval;
 830 }
 831
 832 /*
 833  * Called with the session lock held.
 834  */
 835 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 836 {
 837         int retval = LTTNG_OK;
 838
 839         if (pid == -1) {
 840                 /* Create empty tracker, replace old tracker. */
 841                 struct ust_pid_tracker tmp_tracker;
 842
 843                 tmp_tracker = session->pid_tracker;
 844                 if (init_pid_tracker(&session->pid_tracker)) {
 845                         ERR("Error initializing PID tracker");
 846                         retval = LTTNG_ERR_NOMEM;
 847                         /* Rollback operation. */
 848                         session->pid_tracker = tmp_tracker;
 849                         goto end;
 850                 }
 851                 fini_pid_tracker(&tmp_tracker);
 852
 853                 /* Remove session from all applications */
 854                 ust_app_global_update_all(session);
 855         } else {
 856                 int ret;
 857                 struct ust_app *app;
 858
 859                 if (!session->pid_tracker.ht) {
 860                         /* No PID being tracked. */
 861                         retval = LTTNG_ERR_PID_NOT_TRACKED;
 862                         goto end;
 863                 }
 864                 /* Remove PID from tracker */
 865                 ret = pid_tracker_del_pid(&session->pid_tracker, pid);
 866                 if (ret != LTTNG_OK) {
 867                         retval = ret;
 868                         goto end;
 869                 }
 870                 /* Remove session from application. */
 871                 app = ust_app_find_by_pid(pid);
 872                 if (app) {
 873                         ust_app_global_update(session, app);
 874                 }
 875         }
 876 end:
 877         return retval;
 878 }
 879
 880 /*
 881  * Called with session lock held.
 882  */
 883 ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
 884                 int32_t **_pids)
 885 {
 886         struct ust_pid_tracker_node *tracker_node;
 887         struct lttng_ht_iter iter;
 888         unsigned long count, i = 0;
 889         long approx[2];
 890         int32_t *pids;
 891         int ret = 0;
 892
 893         if (!session->pid_tracker.ht) {
 894                 /* Tracker disabled. Set first entry to -1. */
 895                 pids = zmalloc(sizeof(*pids));
 896                 if (!pids) {
 897                         ret = -1;
 898                         goto end;
 899                 }
 900                 pids[0] = -1;
 901                 *_pids = pids;
 902                 return 1;
 903         }
 904
 905         rcu_read_lock();
 906         cds_lfht_count_nodes(session->pid_tracker.ht->ht,
 907                 &approx[0], &count, &approx[1]);
 908         pids = zmalloc(sizeof(*pids) * count);
 909         if (!pids) {
 910                 ret = -1;
 911                 goto end;
 912         }
 913         cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
 914                         &iter.iter, tracker_node, node.node) {
 915                 pids[i++] = tracker_node->node.key;
 916         }
 917         *_pids = pids;
 918         ret = count;
 919 end:
 920         rcu_read_unlock();
 921         return ret;
 922 }
 923
 924 /*
 925  * RCU safe free context structure.
 926  */
 927 static void destroy_context_rcu(struct rcu_head *head)
 928 {
 929         struct lttng_ht_node_ulong *node =
 930                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 931         struct ltt_ust_context *ctx =
 932                 caa_container_of(node, struct ltt_ust_context, node);
 933
 934         free(ctx);
 935 }
 936
 937 /*
 938  * Cleanup UST context hash table.
 939  */
 940 static void destroy_contexts(struct lttng_ht *ht)
 941 {
 942         int ret;
 943         struct lttng_ht_node_ulong *node;
 944         struct lttng_ht_iter iter;
 945         struct ltt_ust_context *ctx;
 946
 947         assert(ht);
 948
 949         rcu_read_lock();
 950         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
 951                 /* Remove from ordered list. */
 952                 ctx = caa_container_of(node, struct ltt_ust_context, node);
 953                 cds_list_del(&ctx->list);
 954                 /* Remove from channel's hash table. */
 955                 ret = lttng_ht_del(ht, &iter);
 956                 if (!ret) {
 957                         call_rcu(&node->head, destroy_context_rcu);
 958                 }
 959         }
 960         rcu_read_unlock();
 961
 962         ht_cleanup_push(ht);
 963 }
 964
 965 /*
 966  * Cleanup ust event structure.
 967  */
 968 void trace_ust_destroy_event(struct ltt_ust_event *event)
 969 {
 970         assert(event);
 971
 972         DBG2("Trace destroy UST event %s", event->attr.name);
 973         free(event->filter_expression);
 974         free(event->filter);
 975         free(event->exclusion);
 976         free(event);
 977 }
 978
 979 /*
 980  * URCU intermediate call to complete destroy event.
 981  */
 982 static void destroy_event_rcu(struct rcu_head *head)
 983 {
 984         struct lttng_ht_node_str *node =
 985                 caa_container_of(head, struct lttng_ht_node_str, head);
 986         struct ltt_ust_event *event =
 987                 caa_container_of(node, struct ltt_ust_event, node);
 988
 989         trace_ust_destroy_event(event);
 990 }
 991
 992 /*
 993  * Cleanup UST events hashtable.
 994  */
 995 static void destroy_events(struct lttng_ht *events)
 996 {
 997         int ret;
 998         struct lttng_ht_node_str *node;
 999         struct lttng_ht_iter iter;
1000
1001         assert(events);
1002
1003         rcu_read_lock();
1004         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1005                 ret = lttng_ht_del(events, &iter);
1006                 assert(!ret);
1007                 call_rcu(&node->head, destroy_event_rcu);
1008         }
1009         rcu_read_unlock();
1010
1011         ht_cleanup_push(events);
1012 }
1013
1014 /*
1015  * Cleanup ust channel structure.
1016  *
1017  * Should _NOT_ be called with RCU read lock held.
1018  */
1019 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1020 {
1021         assert(channel);
1022
1023         DBG2("Trace destroy UST channel %s", channel->name);
1024
1025         free(channel);
1026 }
1027
1028 /*
1029  * URCU intermediate call to complete destroy channel.
1030  */
1031 static void destroy_channel_rcu(struct rcu_head *head)
1032 {
1033         struct lttng_ht_node_str *node =
1034                 caa_container_of(head, struct lttng_ht_node_str, head);
1035         struct ltt_ust_channel *channel =
1036                 caa_container_of(node, struct ltt_ust_channel, node);
1037
1038         _trace_ust_destroy_channel(channel);
1039 }
1040
1041 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1042 {
1043         /* Destroying all events of the channel */
1044         destroy_events(channel->events);
1045         /* Destroying all context of the channel */
1046         destroy_contexts(channel->ctx);
1047
1048         call_rcu(&channel->node.head, destroy_channel_rcu);
1049 }
1050
1051 /*
1052  * Remove an UST channel from a channel HT.
1053  */
1054 void trace_ust_delete_channel(struct lttng_ht *ht,
1055                 struct ltt_ust_channel *channel)
1056 {
1057         int ret;
1058         struct lttng_ht_iter iter;
1059
1060         assert(ht);
1061         assert(channel);
1062
1063         iter.iter.node = &channel->node.node;
1064         ret = lttng_ht_del(ht, &iter);
1065         assert(!ret);
1066 }
1067
1068 /*
1069  * Iterate over a hash table containing channels and cleanup safely.
1070  */
1071 static void destroy_channels(struct lttng_ht *channels)
1072 {
1073         struct lttng_ht_node_str *node;
1074         struct lttng_ht_iter iter;
1075
1076         assert(channels);
1077
1078         rcu_read_lock();
1079         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1080                 struct ltt_ust_channel *chan =
1081                         caa_container_of(node, struct ltt_ust_channel, node);
1082
1083                 trace_ust_delete_channel(channels, chan);
1084                 trace_ust_destroy_channel(chan);
1085         }
1086         rcu_read_unlock();
1087
1088         ht_cleanup_push(channels);
1089 }
1090
1091 /*
1092  * Cleanup UST global domain.
1093  */
1094 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1095 {
1096         assert(dom);
1097
1098         destroy_channels(dom->channels);
1099 }
1100
1101 /*
1102  * Cleanup ust session structure
1103  *
1104  * Should *NOT* be called with RCU read-side lock held.
1105  */
1106 void trace_ust_destroy_session(struct ltt_ust_session *session)
1107 {
1108         struct agent *agt;
1109         struct buffer_reg_uid *reg, *sreg;
1110         struct lttng_ht_iter iter;
1111
1112         assert(session);
1113
1114         DBG2("Trace UST destroy session %" PRIu64, session->id);
1115
1116         /* Cleaning up UST domain */
1117         destroy_domain_global(&session->domain_global);
1118
1119         rcu_read_lock();
1120         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1121                 int ret = lttng_ht_del(session->agents, &iter);
1122
1123                 assert(!ret);
1124                 agent_destroy(agt);
1125         }
1126         rcu_read_unlock();
1127
1128         ht_cleanup_push(session->agents);
1129
1130         /* Cleanup UID buffer registry object(s). */
1131         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1132                         lnode) {
1133                 cds_list_del(&reg->lnode);
1134                 buffer_reg_uid_remove(reg);
1135                 buffer_reg_uid_destroy(reg, session->consumer);
1136         }
1137
1138         consumer_output_put(session->consumer);
1139
1140         fini_pid_tracker(&session->pid_tracker);
1141
1142         free(session);
1143 }