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