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                 enum lttng_domain_type domain)
 313 {
 314         struct ltt_ust_channel *luc;
 315
 316         assert(chan);
 317
 318         luc = zmalloc(sizeof(struct ltt_ust_channel));
 319         if (luc == NULL) {
 320                 PERROR("ltt_ust_channel zmalloc");
 321                 goto error;
 322         }
 323
 324         luc->domain = domain;
 325
 326         /* Copy UST channel attributes */
 327         luc->attr.overwrite = chan->attr.overwrite;
 328         luc->attr.subbuf_size = chan->attr.subbuf_size;
 329         luc->attr.num_subbuf = chan->attr.num_subbuf;
 330         luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
 331         luc->attr.read_timer_interval = chan->attr.read_timer_interval;
 332         luc->attr.output = (enum lttng_ust_output) chan->attr.output;
 333
 334         /* Translate to UST output enum */
 335         switch (luc->attr.output) {
 336         default:
 337                 luc->attr.output = LTTNG_UST_MMAP;
 338                 break;
 339         }
 340
 341         /*
 342          * If we receive an empty string for channel name, it means the
 343          * default channel name is requested.
 344          */
 345         if (chan->name[0] == '\0') {
 346                 strncpy(luc->name, DEFAULT_CHANNEL_NAME, sizeof(luc->name));
 347         } else {
 348                 /* Copy channel name */
 349                 strncpy(luc->name, chan->name, sizeof(luc->name));
 350         }
 351         luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 352
 353         /* Init node */
 354         lttng_ht_node_init_str(&luc->node, luc->name);
 355         CDS_INIT_LIST_HEAD(&luc->ctx_list);
 356
 357         /* Alloc hash tables */
 358         luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 359         luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 360
 361         /* On-disk circular buffer parameters */
 362         luc->tracefile_size = chan->attr.tracefile_size;
 363         luc->tracefile_count = chan->attr.tracefile_count;
 364
 365         DBG2("Trace UST channel %s created", luc->name);
 366
 367 error:
 368         return luc;
 369 }
 370
 371 /*
 372  * Allocate and initialize a ust event. Set name and event type.
 373  * We own filter_expression, filter, and exclusion.
 374  *
 375  * Return pointer to structure or NULL.
 376  */
 377 struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev,
 378                 char *filter_expression,
 379                 struct lttng_filter_bytecode *filter,
 380                 struct lttng_event_exclusion *exclusion,
 381                 bool internal_event)
 382 {
 383         struct ltt_ust_event *lue;
 384
 385         assert(ev);
 386
 387         lue = zmalloc(sizeof(struct ltt_ust_event));
 388         if (lue == NULL) {
 389                 PERROR("ust event zmalloc");
 390                 goto error;
 391         }
 392
 393         lue->internal = internal_event;
 394
 395         switch (ev->type) {
 396         case LTTNG_EVENT_PROBE:
 397                 lue->attr.instrumentation = LTTNG_UST_PROBE;
 398                 break;
 399         case LTTNG_EVENT_FUNCTION:
 400                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 401                 break;
 402         case LTTNG_EVENT_FUNCTION_ENTRY:
 403                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 404                 break;
 405         case LTTNG_EVENT_TRACEPOINT:
 406                 lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 407                 break;
 408         default:
 409                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 410                 goto error_free_event;
 411         }
 412
 413         /* Copy event name */
 414         strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 415         lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 416
 417         switch (ev->loglevel_type) {
 418         case LTTNG_EVENT_LOGLEVEL_ALL:
 419                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 420                 lue->attr.loglevel = -1;        /* Force to -1 */
 421                 break;
 422         case LTTNG_EVENT_LOGLEVEL_RANGE:
 423                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 424                 lue->attr.loglevel = ev->loglevel;
 425                 break;
 426         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 427                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 428                 lue->attr.loglevel = ev->loglevel;
 429                 break;
 430         default:
 431                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 432                 goto error_free_event;
 433         }
 434
 435         /* Same layout. */
 436         lue->filter_expression = filter_expression;
 437         lue->filter = filter;
 438         lue->exclusion = exclusion;
 439
 440         /* Init node */
 441         lttng_ht_node_init_str(&lue->node, lue->attr.name);
 442
 443         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 444                 lue->attr.name, lue->attr.loglevel_type,
 445                 lue->attr.loglevel);
 446
 447         return lue;
 448
 449 error_free_event:
 450         free(lue);
 451 error:
 452         free(filter_expression);
 453         free(filter);
 454         free(exclusion);
 455         return NULL;
 456 }
 457
 458 static
 459 int trace_ust_context_type_event_to_ust(enum lttng_event_context_type type)
 460 {
 461         int utype;
 462
 463         switch (type) {
 464         case LTTNG_EVENT_CONTEXT_VTID:
 465                 utype = LTTNG_UST_CONTEXT_VTID;
 466                 break;
 467         case LTTNG_EVENT_CONTEXT_VPID:
 468                 utype = LTTNG_UST_CONTEXT_VPID;
 469                 break;
 470         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 471                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 472                 break;
 473         case LTTNG_EVENT_CONTEXT_PROCNAME:
 474                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 475                 break;
 476         case LTTNG_EVENT_CONTEXT_IP:
 477                 utype = LTTNG_UST_CONTEXT_IP;
 478                 break;
 479         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 480                 if (!ustctl_has_perf_counters()) {
 481                         utype = -1;
 482                         WARN("Perf counters not implemented in UST");
 483                 } else {
 484                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 485                 }
 486                 break;
 487         default:
 488                 ERR("Invalid UST context");
 489                 utype = -1;
 490                 break;
 491         }
 492         return utype;
 493 }
 494
 495 /*
 496  * Return 1 if contexts match, 0 otherwise.
 497  */
 498 int trace_ust_match_context(struct ltt_ust_context *uctx,
 499                 struct lttng_event_context *ctx)
 500 {
 501         int utype;
 502
 503         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 504         if (utype < 0) {
 505                 return 0;
 506         }
 507         if (uctx->ctx.ctx != utype) {
 508                 return 0;
 509         }
 510         switch (utype) {
 511         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 512                 if (uctx->ctx.u.perf_counter.type
 513                                 != ctx->u.perf_counter.type) {
 514                         return 0;
 515                 }
 516                 if (uctx->ctx.u.perf_counter.config
 517                                 != ctx->u.perf_counter.config) {
 518                         return 0;
 519                 }
 520                 if (strncmp(uctx->ctx.u.perf_counter.name,
 521                                 ctx->u.perf_counter.name,
 522                                 LTTNG_UST_SYM_NAME_LEN)) {
 523                         return 0;
 524                 }
 525                 break;
 526         default:
 527                 break;
 528
 529         }
 530         return 1;
 531 }
 532
 533 /*
 534  * Allocate and initialize an UST context.
 535  *
 536  * Return pointer to structure or NULL.
 537  */
 538 struct ltt_ust_context *trace_ust_create_context(
 539                 struct lttng_event_context *ctx)
 540 {
 541         struct ltt_ust_context *uctx;
 542         int utype;
 543
 544         assert(ctx);
 545
 546         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 547         if (utype < 0) {
 548                 return NULL;
 549         }
 550
 551         uctx = zmalloc(sizeof(struct ltt_ust_context));
 552         if (uctx == NULL) {
 553                 PERROR("zmalloc ltt_ust_context");
 554                 goto error;
 555         }
 556
 557         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 558         switch (utype) {
 559         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 560                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 561                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 562                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 563                                 LTTNG_UST_SYM_NAME_LEN);
 564                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 565                 break;
 566         default:
 567                 break;
 568         }
 569         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 570
 571         return uctx;
 572
 573 error:
 574         return NULL;
 575 }
 576
 577 static
 578 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 579 {
 580         struct ust_pid_tracker_node *tracker_node =
 581                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 582         free(tracker_node);
 583 }
 584
 585 static
 586 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 587 {
 588
 589         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 590 }
 591
 592 static
 593 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 594 {
 595         int ret = 0;
 596
 597         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 598         if (!pid_tracker->ht) {
 599                 ret = -1;
 600                 goto end;
 601         }
 602
 603 end:
 604         return ret;
 605 }
 606
 607 /*
 608  * Teardown pid tracker content, but don't free pid_tracker object.
 609  */
 610 static
 611 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 612 {
 613         struct ust_pid_tracker_node *tracker_node;
 614         struct lttng_ht_iter iter;
 615
 616         if (!pid_tracker->ht) {
 617                 return;
 618         }
 619         rcu_read_lock();
 620         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 621                         &iter.iter, tracker_node, node.node) {
 622                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 623
 624                 assert(!ret);
 625                 destroy_pid_tracker_node(tracker_node);
 626         }
 627         rcu_read_unlock();
 628         ht_cleanup_push(pid_tracker->ht);
 629         pid_tracker->ht = NULL;
 630 }
 631
 632 static
 633 struct ust_pid_tracker_node *pid_tracker_lookup(
 634                 struct ust_pid_tracker *pid_tracker, int pid,
 635                 struct lttng_ht_iter *iter)
 636 {
 637         unsigned long _pid = (unsigned long) pid;
 638         struct lttng_ht_node_ulong *node;
 639
 640         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 641         node = lttng_ht_iter_get_node_ulong(iter);
 642         if (node) {
 643                 return caa_container_of(node, struct ust_pid_tracker_node,
 644                         node);
 645         } else {
 646                 return NULL;
 647         }
 648 }
 649
 650 static
 651 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 652 {
 653         int retval = LTTNG_OK;
 654         struct ust_pid_tracker_node *tracker_node;
 655         struct lttng_ht_iter iter;
 656
 657         if (pid < 0) {
 658                 retval = LTTNG_ERR_INVALID;
 659                 goto end;
 660         }
 661         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 662         if (tracker_node) {
 663                 /* Already exists. */
 664                 retval = LTTNG_ERR_PID_TRACKED;
 665                 goto end;
 666         }
 667         tracker_node = zmalloc(sizeof(*tracker_node));
 668         if (!tracker_node) {
 669                 retval = LTTNG_ERR_NOMEM;
 670                 goto end;
 671         }
 672         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 673         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 674 end:
 675         return retval;
 676 }
 677
 678 static
 679 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 680 {
 681         int retval = LTTNG_OK, ret;
 682         struct ust_pid_tracker_node *tracker_node;
 683         struct lttng_ht_iter iter;
 684
 685         if (pid < 0) {
 686                 retval = LTTNG_ERR_INVALID;
 687                 goto end;
 688         }
 689         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 690         if (!tracker_node) {
 691                 /* Not found */
 692                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 693                 goto end;
 694         }
 695         ret = lttng_ht_del(pid_tracker->ht, &iter);
 696         assert(!ret);
 697
 698         destroy_pid_tracker_node(tracker_node);
 699 end:
 700         return retval;
 701 }
 702
 703 /*
 704  * The session lock is held when calling this function.
 705  */
 706 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 707 {
 708         struct lttng_ht_iter iter;
 709
 710         if (!session->pid_tracker.ht) {
 711                 return 1;
 712         }
 713         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 714                 return 1;
 715         }
 716         return 0;
 717 }
 718
 719 /*
 720  * Called with the session lock held.
 721  */
 722 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 723 {
 724         int retval = LTTNG_OK;
 725
 726         if (pid == -1) {
 727                 /* Track all pids: destroy tracker if exists. */
 728                 if (session->pid_tracker.ht) {
 729                         fini_pid_tracker(&session->pid_tracker);
 730                         /* Ensure all apps have session. */
 731                         ust_app_global_update_all(session);
 732                 }
 733         } else {
 734                 int ret;
 735
 736                 if (!session->pid_tracker.ht) {
 737                         /* Create tracker. */
 738                         if (init_pid_tracker(&session->pid_tracker)) {
 739                                 ERR("Error initializing PID tracker");
 740                                 retval = LTTNG_ERR_NOMEM;
 741                                 goto end;
 742                         }
 743                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 744                         if (ret != LTTNG_OK) {
 745                                 retval = ret;
 746                                 fini_pid_tracker(&session->pid_tracker);
 747                                 goto end;
 748                         }
 749                         /* Remove all apps from session except pid. */
 750                         ust_app_global_update_all(session);
 751                 } else {
 752                         struct ust_app *app;
 753
 754                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 755                         if (ret != LTTNG_OK) {
 756                                 retval = ret;
 757                                 goto end;
 758                         }
 759                         /* Add session to application */
 760                         app = ust_app_find_by_pid(pid);
 761                         if (app) {
 762                                 ust_app_global_update(session, app);
 763                         }
 764                 }
 765         }
 766 end:
 767         return retval;
 768 }
 769
 770 /*
 771  * Called with the session lock held.
 772  */
 773 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 774 {
 775         int retval = LTTNG_OK;
 776
 777         if (pid == -1) {
 778                 /* Create empty tracker, replace old tracker. */
 779                 struct ust_pid_tracker tmp_tracker;
 780
 781                 tmp_tracker = session->pid_tracker;
 782                 if (init_pid_tracker(&session->pid_tracker)) {
 783                         ERR("Error initializing PID tracker");
 784                         retval = LTTNG_ERR_NOMEM;
 785                         /* Rollback operation. */
 786                         session->pid_tracker = tmp_tracker;
 787                         goto end;
 788                 }
 789                 fini_pid_tracker(&tmp_tracker);
 790
 791                 /* Remove session from all applications */
 792                 ust_app_global_update_all(session);
 793         } else {
 794                 int ret;
 795                 struct ust_app *app;
 796
 797                 if (!session->pid_tracker.ht) {
 798                         retval = LTTNG_ERR_INVALID;
 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         /* Destroying all events of the channel */
 963         destroy_events(channel->events);
 964         /* Destroying all context of the channel */
 965         destroy_contexts(channel->ctx);
 966
 967         free(channel);
 968 }
 969
 970 /*
 971  * URCU intermediate call to complete destroy channel.
 972  */
 973 static void destroy_channel_rcu(struct rcu_head *head)
 974 {
 975         struct lttng_ht_node_str *node =
 976                 caa_container_of(head, struct lttng_ht_node_str, head);
 977         struct ltt_ust_channel *channel =
 978                 caa_container_of(node, struct ltt_ust_channel, node);
 979
 980         _trace_ust_destroy_channel(channel);
 981 }
 982
 983 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
 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         int ret;
1011         struct lttng_ht_node_str *node;
1012         struct lttng_ht_iter iter;
1013
1014         assert(channels);
1015
1016         rcu_read_lock();
1017
1018         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1019                 ret = lttng_ht_del(channels, &iter);
1020                 assert(!ret);
1021                 call_rcu(&node->head, destroy_channel_rcu);
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_destroy_output(session->consumer);
1076         consumer_destroy_output(session->tmp_consumer);
1077
1078         fini_pid_tracker(&session->pid_tracker);
1079
1080         free(session);
1081 }