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