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