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