src/bin/lttng-sessiond/trace-ust.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  * Copyright (C) 2016 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  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                 size_t i;
 121
 122                 /* Check exclusion counts first. */
 123                 if (event->exclusion->count != key->exclusion->count) {
 124                         goto no_match;
 125                 }
 126
 127                 /* Compare names individually. */
 128                 for (i = 0; i < event->exclusion->count; ++i) {
 129                         size_t j;
 130                         bool found = false;
 131                         const char *name_ev =
 132                                 LTTNG_EVENT_EXCLUSION_NAME_AT(
 133                                         event->exclusion, i);
 134
 135                         /*
 136                          * Compare this exclusion name to all the key's
 137                          * exclusion names.
 138                          */
 139                         for (j = 0; j < key->exclusion->count; ++j) {
 140                                 const char *name_key =
 141                                         LTTNG_EVENT_EXCLUSION_NAME_AT(
 142                                                 key->exclusion, j);
 143
 144                                 if (!strncmp(name_ev, name_key,
 145                                                 LTTNG_SYMBOL_NAME_LEN)) {
 146                                         /* Names match! */
 147                                         found = true;
 148                                         break;
 149                                 }
 150                         }
 151
 152                         /*
 153                          * If the current exclusion name was not found amongst
 154                          * the key's exclusion names, then there's no match.
 155                          */
 156                         if (!found) {
 157                                 goto no_match;
 158                         }
 159                 }
 160         }
 161         /* Match. */
 162         return 1;
 163
 164 no_match:
 165         return 0;
 166 }
 167
 168 /*
 169  * Find the channel in the hashtable and return channel pointer. RCU read side
 170  * lock MUST be acquired before calling this.
 171  */
 172 struct ltt_ust_channel *trace_ust_find_channel_by_name(struct lttng_ht *ht,
 173                 char *name)
 174 {
 175         struct lttng_ht_node_str *node;
 176         struct lttng_ht_iter iter;
 177
 178         /*
 179          * If we receive an empty string for channel name, it means the
 180          * default channel name is requested.
 181          */
 182         if (name[0] == '\0')
 183                 name = DEFAULT_CHANNEL_NAME;
 184
 185         lttng_ht_lookup(ht, (void *)name, &iter);
 186         node = lttng_ht_iter_get_node_str(&iter);
 187         if (node == NULL) {
 188                 goto error;
 189         }
 190
 191         DBG2("Trace UST channel %s found by name", name);
 192
 193         return caa_container_of(node, struct ltt_ust_channel, node);
 194
 195 error:
 196         DBG2("Trace UST channel %s not found by name", name);
 197         return NULL;
 198 }
 199
 200 /*
 201  * Find the event in the hashtable and return event pointer. RCU read side lock
 202  * MUST be acquired before calling this.
 203  */
 204 struct ltt_ust_event *trace_ust_find_event(struct lttng_ht *ht,
 205                 char *name, struct lttng_filter_bytecode *filter,
 206                 enum lttng_ust_loglevel_type loglevel_type, int loglevel_value,
 207                 struct lttng_event_exclusion *exclusion)
 208 {
 209         struct lttng_ht_node_str *node;
 210         struct lttng_ht_iter iter;
 211         struct ltt_ust_ht_key key;
 212
 213         assert(name);
 214         assert(ht);
 215
 216         key.name = name;
 217         key.filter = filter;
 218         key.loglevel_type = loglevel_type;
 219         key.loglevel_value = loglevel_value;
 220         key.exclusion = exclusion;
 221
 222         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 223                         trace_ust_ht_match_event, &key, &iter.iter);
 224         node = lttng_ht_iter_get_node_str(&iter);
 225         if (node == NULL) {
 226                 goto error;
 227         }
 228
 229         DBG2("Trace UST event %s found", key.name);
 230
 231         return caa_container_of(node, struct ltt_ust_event, node);
 232
 233 error:
 234         DBG2("Trace UST event %s NOT found", key.name);
 235         return NULL;
 236 }
 237
 238 /*
 239  * Lookup an agent in the session agents hash table by domain type and return
 240  * the object if found else NULL.
 241  *
 242  * RCU read side lock must be acquired before calling and only released
 243  * once the agent is no longer in scope or being used.
 244  */
 245 struct agent *trace_ust_find_agent(struct ltt_ust_session *session,
 246                 enum lttng_domain_type domain_type)
 247 {
 248         struct agent *agt = NULL;
 249         struct lttng_ht_node_u64 *node;
 250         struct lttng_ht_iter iter;
 251         uint64_t key;
 252
 253         assert(session);
 254
 255         DBG3("Trace ust agent lookup for domain %d", domain_type);
 256
 257         key = domain_type;
 258
 259         lttng_ht_lookup(session->agents, &key, &iter);
 260         node = lttng_ht_iter_get_node_u64(&iter);
 261         if (!node) {
 262                 goto end;
 263         }
 264         agt = caa_container_of(node, struct agent, node);
 265
 266 end:
 267         return agt;
 268 }
 269
 270 /*
 271  * Allocate and initialize a ust session data structure.
 272  *
 273  * Return pointer to structure or NULL.
 274  */
 275 struct ltt_ust_session *trace_ust_create_session(uint64_t session_id)
 276 {
 277         struct ltt_ust_session *lus;
 278
 279         /* Allocate a new ltt ust session */
 280         lus = zmalloc(sizeof(struct ltt_ust_session));
 281         if (lus == NULL) {
 282                 PERROR("create ust session zmalloc");
 283                 goto error;
 284         }
 285
 286         /* Init data structure */
 287         lus->id = session_id;
 288         lus->active = 0;
 289
 290         /* Set default metadata channel attribute. */
 291         lus->metadata_attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 292         lus->metadata_attr.subbuf_size = default_get_metadata_subbuf_size();
 293         lus->metadata_attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 294         lus->metadata_attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
 295         lus->metadata_attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;
 296         lus->metadata_attr.output = LTTNG_UST_MMAP;
 297
 298         /*
 299          * Default buffer type. This can be changed through an enable channel
 300          * requesting a different type. Note that this can only be changed once
 301          * during the session lifetime which is at the first enable channel and
 302          * only before start. The flag buffer_type_changed indicates the status.
 303          */
 304         lus->buffer_type = LTTNG_BUFFER_PER_UID;
 305         /* Once set to 1, the buffer_type is immutable for the session. */
 306         lus->buffer_type_changed = 0;
 307         /* Init it in case it get used after allocation. */
 308         CDS_INIT_LIST_HEAD(&lus->buffer_reg_uid_list);
 309
 310         /* Alloc UST global domain channels' HT */
 311         lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 312         /* Alloc agent hash table. */
 313         lus->agents = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 314
 315         lus->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 316         if (lus->consumer == NULL) {
 317                 goto error_consumer;
 318         }
 319
 320         DBG2("UST trace session create successful");
 321
 322         return lus;
 323
 324 error_consumer:
 325         ht_cleanup_push(lus->domain_global.channels);
 326         ht_cleanup_push(lus->agents);
 327         free(lus);
 328 error:
 329         return NULL;
 330 }
 331
 332 /*
 333  * Allocate and initialize a ust channel data structure.
 334  *
 335  * Return pointer to structure or NULL.
 336  */
 337 struct ltt_ust_channel *trace_ust_create_channel(struct lttng_channel *chan,
 338                 enum lttng_domain_type domain)
 339 {
 340         struct ltt_ust_channel *luc;
 341
 342         assert(chan);
 343
 344         luc = zmalloc(sizeof(struct ltt_ust_channel));
 345         if (luc == NULL) {
 346                 PERROR("ltt_ust_channel zmalloc");
 347                 goto error;
 348         }
 349
 350         luc->domain = domain;
 351
 352         /* Copy UST channel attributes */
 353         luc->attr.overwrite = chan->attr.overwrite;
 354         luc->attr.subbuf_size = chan->attr.subbuf_size;
 355         luc->attr.num_subbuf = chan->attr.num_subbuf;
 356         luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
 357         luc->attr.read_timer_interval = chan->attr.read_timer_interval;
 358         luc->attr.output = (enum lttng_ust_output) chan->attr.output;
 359         luc->monitor_timer_interval = ((struct lttng_channel_extended *)
 360                         chan->attr.extended.ptr)->monitor_timer_interval;
 361         luc->attr.u.s.blocking_timeout = ((struct lttng_channel_extended *)
 362                         chan->attr.extended.ptr)->blocking_timeout;
 363
 364         /* Translate to UST output enum */
 365         switch (luc->attr.output) {
 366         default:
 367                 luc->attr.output = LTTNG_UST_MMAP;
 368                 break;
 369         }
 370
 371         /*
 372          * If we receive an empty string for channel name, it means the
 373          * default channel name is requested.
 374          */
 375         if (chan->name[0] == '\0') {
 376                 strncpy(luc->name, DEFAULT_CHANNEL_NAME, sizeof(luc->name));
 377         } else {
 378                 /* Copy channel name */
 379                 strncpy(luc->name, chan->name, sizeof(luc->name));
 380         }
 381         luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 382
 383         /* Init node */
 384         lttng_ht_node_init_str(&luc->node, luc->name);
 385         CDS_INIT_LIST_HEAD(&luc->ctx_list);
 386
 387         /* Alloc hash tables */
 388         luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 389         luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 390
 391         /* On-disk circular buffer parameters */
 392         luc->tracefile_size = chan->attr.tracefile_size;
 393         luc->tracefile_count = chan->attr.tracefile_count;
 394
 395         DBG2("Trace UST channel %s created", luc->name);
 396
 397 error:
 398         return luc;
 399 }
 400
 401 /*
 402  * Validates an exclusion list.
 403  *
 404  * Returns 0 if valid, negative value if invalid.
 405  */
 406 static int validate_exclusion(struct lttng_event_exclusion *exclusion)
 407 {
 408         size_t i;
 409         int ret = 0;
 410
 411         assert(exclusion);
 412
 413         for (i = 0; i < exclusion->count; ++i) {
 414                 size_t j;
 415                 const char *name_a =
 416                         LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, i);
 417
 418                 for (j = 0; j < i; ++j) {
 419                         const char *name_b =
 420                                 LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, j);
 421
 422                         if (!strncmp(name_a, name_b, LTTNG_SYMBOL_NAME_LEN)) {
 423                                 /* Match! */
 424                                 ret = -1;
 425                                 goto end;
 426                         }
 427                 }
 428         }
 429
 430 end:
 431         return ret;
 432 }
 433
 434 /*
 435  * Allocate and initialize a ust event. Set name and event type.
 436  * We own filter_expression, filter, and exclusion.
 437  *
 438  * Return an lttng_error_code
 439  */
 440 enum lttng_error_code trace_ust_create_event(struct lttng_event *ev,
 441                 char *filter_expression,
 442                 struct lttng_filter_bytecode *filter,
 443                 struct lttng_event_exclusion *exclusion,
 444                 bool internal_event,
 445                 struct ltt_ust_event **ust_event)
 446 {
 447         struct ltt_ust_event *local_ust_event;
 448         enum lttng_error_code ret = LTTNG_OK;
 449
 450         assert(ev);
 451
 452         if (exclusion && validate_exclusion(exclusion)) {
 453                 ret = LTTNG_ERR_INVALID;
 454                 goto error;
 455         }
 456
 457         local_ust_event = zmalloc(sizeof(struct ltt_ust_event));
 458         if (local_ust_event == NULL) {
 459                 PERROR("ust event zmalloc");
 460                 ret = LTTNG_ERR_NOMEM;
 461                 goto error;
 462         }
 463
 464         local_ust_event->internal = internal_event;
 465
 466         switch (ev->type) {
 467         case LTTNG_EVENT_PROBE:
 468                 local_ust_event->attr.instrumentation = LTTNG_UST_PROBE;
 469                 break;
 470         case LTTNG_EVENT_FUNCTION:
 471                 local_ust_event->attr.instrumentation = LTTNG_UST_FUNCTION;
 472                 break;
 473         case LTTNG_EVENT_FUNCTION_ENTRY:
 474                 local_ust_event->attr.instrumentation = LTTNG_UST_FUNCTION;
 475                 break;
 476         case LTTNG_EVENT_TRACEPOINT:
 477                 local_ust_event->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 478                 break;
 479         default:
 480                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 481                 ret = LTTNG_ERR_INVALID;
 482                 goto error_free_event;
 483         }
 484
 485         /* Copy event name */
 486         strncpy(local_ust_event->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 487         local_ust_event->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 488
 489         switch (ev->loglevel_type) {
 490         case LTTNG_EVENT_LOGLEVEL_ALL:
 491                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 492                 local_ust_event->attr.loglevel = -1;    /* Force to -1 */
 493                 break;
 494         case LTTNG_EVENT_LOGLEVEL_RANGE:
 495                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 496                 local_ust_event->attr.loglevel = ev->loglevel;
 497                 break;
 498         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 499                 local_ust_event->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 500                 local_ust_event->attr.loglevel = ev->loglevel;
 501                 break;
 502         default:
 503                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 504                 ret = LTTNG_ERR_INVALID;
 505                 goto error_free_event;
 506         }
 507
 508         /* Same layout. */
 509         local_ust_event->filter_expression = filter_expression;
 510         local_ust_event->filter = filter;
 511         local_ust_event->exclusion = exclusion;
 512
 513         /* Init node */
 514         lttng_ht_node_init_str(&local_ust_event->node, local_ust_event->attr.name);
 515
 516         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 517                 local_ust_event->attr.name, local_ust_event->attr.loglevel_type,
 518                 local_ust_event->attr.loglevel);
 519
 520         *ust_event = local_ust_event;
 521
 522         return ret;
 523
 524 error_free_event:
 525         free(local_ust_event);
 526 error:
 527         free(filter_expression);
 528         free(filter);
 529         free(exclusion);
 530         return ret;
 531 }
 532
 533 static
 534 int trace_ust_context_type_event_to_ust(
 535                 enum lttng_event_context_type type)
 536 {
 537         int utype;
 538
 539         switch (type) {
 540         case LTTNG_EVENT_CONTEXT_VTID:
 541                 utype = LTTNG_UST_CONTEXT_VTID;
 542                 break;
 543         case LTTNG_EVENT_CONTEXT_VPID:
 544                 utype = LTTNG_UST_CONTEXT_VPID;
 545                 break;
 546         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 547                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 548                 break;
 549         case LTTNG_EVENT_CONTEXT_PROCNAME:
 550                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 551                 break;
 552         case LTTNG_EVENT_CONTEXT_IP:
 553                 utype = LTTNG_UST_CONTEXT_IP;
 554                 break;
 555         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 556                 if (!ustctl_has_perf_counters()) {
 557                         utype = -1;
 558                         WARN("Perf counters not implemented in UST");
 559                 } else {
 560                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 561                 }
 562                 break;
 563         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
 564                 utype = LTTNG_UST_CONTEXT_APP_CONTEXT;
 565                 break;
 566         default:
 567                 utype = -1;
 568                 break;
 569         }
 570         return utype;
 571 }
 572
 573 /*
 574  * Return 1 if contexts match, 0 otherwise.
 575  */
 576 int trace_ust_match_context(struct ltt_ust_context *uctx,
 577                 struct lttng_event_context *ctx)
 578 {
 579         int utype;
 580
 581         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 582         if (utype < 0) {
 583                 return 0;
 584         }
 585         if (uctx->ctx.ctx != utype) {
 586                 return 0;
 587         }
 588         switch (utype) {
 589         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 590                 if (uctx->ctx.u.perf_counter.type
 591                                 != ctx->u.perf_counter.type) {
 592                         return 0;
 593                 }
 594                 if (uctx->ctx.u.perf_counter.config
 595                                 != ctx->u.perf_counter.config) {
 596                         return 0;
 597                 }
 598                 if (strncmp(uctx->ctx.u.perf_counter.name,
 599                                 ctx->u.perf_counter.name,
 600                                 LTTNG_UST_SYM_NAME_LEN)) {
 601                         return 0;
 602                 }
 603                 break;
 604         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 605                 assert(uctx->ctx.u.app_ctx.provider_name);
 606                 assert(uctx->ctx.u.app_ctx.ctx_name);
 607                 if (strcmp(uctx->ctx.u.app_ctx.provider_name,
 608                                 ctx->u.app_ctx.provider_name) ||
 609                                 strcmp(uctx->ctx.u.app_ctx.ctx_name,
 610                                 ctx->u.app_ctx.ctx_name)) {
 611                         return 0;
 612                 }
 613         default:
 614                 break;
 615
 616         }
 617         return 1;
 618 }
 619
 620 /*
 621  * Allocate and initialize an UST context.
 622  *
 623  * Return pointer to structure or NULL.
 624  */
 625 struct ltt_ust_context *trace_ust_create_context(
 626                 struct lttng_event_context *ctx)
 627 {
 628         struct ltt_ust_context *uctx = NULL;
 629         int utype;
 630
 631         assert(ctx);
 632
 633         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 634         if (utype < 0) {
 635                 ERR("Invalid UST context");
 636                 goto end;
 637         }
 638
 639         uctx = zmalloc(sizeof(struct ltt_ust_context));
 640         if (!uctx) {
 641                 PERROR("zmalloc ltt_ust_context");
 642                 goto end;
 643         }
 644
 645         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 646         switch (utype) {
 647         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 648                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 649                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 650                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 651                                 LTTNG_UST_SYM_NAME_LEN);
 652                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 653                 break;
 654         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 655         {
 656                 char *provider_name = NULL, *ctx_name = NULL;
 657
 658                 provider_name = strdup(ctx->u.app_ctx.provider_name);
 659                 if (!provider_name) {
 660                         goto error;
 661                 }
 662                 uctx->ctx.u.app_ctx.provider_name = provider_name;
 663
 664                 ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 665                 if (!ctx_name) {
 666                         goto error;
 667                 }
 668                 uctx->ctx.u.app_ctx.ctx_name = ctx_name;
 669                 break;
 670         }
 671         default:
 672                 break;
 673         }
 674         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 675 end:
 676         return uctx;
 677 error:
 678         trace_ust_destroy_context(uctx);
 679         return NULL;
 680 }
 681
 682 static
 683 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 684 {
 685         struct ust_pid_tracker_node *tracker_node =
 686                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 687         free(tracker_node);
 688 }
 689
 690 static
 691 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 692 {
 693
 694         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 695 }
 696
 697 static
 698 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 699 {
 700         int ret = 0;
 701
 702         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 703         if (!pid_tracker->ht) {
 704                 ret = -1;
 705                 goto end;
 706         }
 707
 708 end:
 709         return ret;
 710 }
 711
 712 /*
 713  * Teardown pid tracker content, but don't free pid_tracker object.
 714  */
 715 static
 716 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 717 {
 718         struct ust_pid_tracker_node *tracker_node;
 719         struct lttng_ht_iter iter;
 720
 721         if (!pid_tracker->ht) {
 722                 return;
 723         }
 724         rcu_read_lock();
 725         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 726                         &iter.iter, tracker_node, node.node) {
 727                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 728
 729                 assert(!ret);
 730                 destroy_pid_tracker_node(tracker_node);
 731         }
 732         rcu_read_unlock();
 733         ht_cleanup_push(pid_tracker->ht);
 734         pid_tracker->ht = NULL;
 735 }
 736
 737 static
 738 struct ust_pid_tracker_node *pid_tracker_lookup(
 739                 struct ust_pid_tracker *pid_tracker, int pid,
 740                 struct lttng_ht_iter *iter)
 741 {
 742         unsigned long _pid = (unsigned long) pid;
 743         struct lttng_ht_node_ulong *node;
 744
 745         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 746         node = lttng_ht_iter_get_node_ulong(iter);
 747         if (node) {
 748                 return caa_container_of(node, struct ust_pid_tracker_node,
 749                         node);
 750         } else {
 751                 return NULL;
 752         }
 753 }
 754
 755 static
 756 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 757 {
 758         int retval = LTTNG_OK;
 759         struct ust_pid_tracker_node *tracker_node;
 760         struct lttng_ht_iter iter;
 761
 762         if (pid < 0) {
 763                 retval = LTTNG_ERR_INVALID;
 764                 goto end;
 765         }
 766         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 767         if (tracker_node) {
 768                 /* Already exists. */
 769                 retval = LTTNG_ERR_PID_TRACKED;
 770                 goto end;
 771         }
 772         tracker_node = zmalloc(sizeof(*tracker_node));
 773         if (!tracker_node) {
 774                 retval = LTTNG_ERR_NOMEM;
 775                 goto end;
 776         }
 777         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 778         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 779 end:
 780         return retval;
 781 }
 782
 783 static
 784 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 785 {
 786         int retval = LTTNG_OK, ret;
 787         struct ust_pid_tracker_node *tracker_node;
 788         struct lttng_ht_iter iter;
 789
 790         if (pid < 0) {
 791                 retval = LTTNG_ERR_INVALID;
 792                 goto end;
 793         }
 794         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 795         if (!tracker_node) {
 796                 /* Not found */
 797                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 798                 goto end;
 799         }
 800         ret = lttng_ht_del(pid_tracker->ht, &iter);
 801         assert(!ret);
 802
 803         destroy_pid_tracker_node(tracker_node);
 804 end:
 805         return retval;
 806 }
 807
 808 /*
 809  * The session lock is held when calling this function.
 810  */
 811 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 812 {
 813         struct lttng_ht_iter iter;
 814
 815         if (!session->pid_tracker.ht) {
 816                 return 1;
 817         }
 818         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 819                 return 1;
 820         }
 821         return 0;
 822 }
 823
 824 /*
 825  * Called with the session lock held.
 826  */
 827 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 828 {
 829         int retval = LTTNG_OK;
 830
 831         if (pid == -1) {
 832                 /* Track all pids: destroy tracker if exists. */
 833                 if (session->pid_tracker.ht) {
 834                         fini_pid_tracker(&session->pid_tracker);
 835                         /* Ensure all apps have session. */
 836                         ust_app_global_update_all(session);
 837                 }
 838         } else {
 839                 int ret;
 840
 841                 if (!session->pid_tracker.ht) {
 842                         /* Create tracker. */
 843                         if (init_pid_tracker(&session->pid_tracker)) {
 844                                 ERR("Error initializing PID tracker");
 845                                 retval = LTTNG_ERR_NOMEM;
 846                                 goto end;
 847                         }
 848                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 849                         if (ret != LTTNG_OK) {
 850                                 retval = ret;
 851                                 fini_pid_tracker(&session->pid_tracker);
 852                                 goto end;
 853                         }
 854                         /* Remove all apps from session except pid. */
 855                         ust_app_global_update_all(session);
 856                 } else {
 857                         struct ust_app *app;
 858
 859                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 860                         if (ret != LTTNG_OK) {
 861                                 retval = ret;
 862                                 goto end;
 863                         }
 864                         /* Add session to application */
 865                         app = ust_app_find_by_pid(pid);
 866                         if (app) {
 867                                 ust_app_global_update(session, app);
 868                         }
 869                 }
 870         }
 871 end:
 872         return retval;
 873 }
 874
 875 /*
 876  * Called with the session lock held.
 877  */
 878 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 879 {
 880         int retval = LTTNG_OK;
 881
 882         if (pid == -1) {
 883                 /* Create empty tracker, replace old tracker. */
 884                 struct ust_pid_tracker tmp_tracker;
 885
 886                 tmp_tracker = session->pid_tracker;
 887                 if (init_pid_tracker(&session->pid_tracker)) {
 888                         ERR("Error initializing PID tracker");
 889                         retval = LTTNG_ERR_NOMEM;
 890                         /* Rollback operation. */
 891                         session->pid_tracker = tmp_tracker;
 892                         goto end;
 893                 }
 894                 fini_pid_tracker(&tmp_tracker);
 895
 896                 /* Remove session from all applications */
 897                 ust_app_global_update_all(session);
 898         } else {
 899                 int ret;
 900                 struct ust_app *app;
 901
 902                 if (!session->pid_tracker.ht) {
 903                         /* No PID being tracked. */
 904                         retval = LTTNG_ERR_PID_NOT_TRACKED;
 905                         goto end;
 906                 }
 907                 /* Remove PID from tracker */
 908                 ret = pid_tracker_del_pid(&session->pid_tracker, pid);
 909                 if (ret != LTTNG_OK) {
 910                         retval = ret;
 911                         goto end;
 912                 }
 913                 /* Remove session from application. */
 914                 app = ust_app_find_by_pid(pid);
 915                 if (app) {
 916                         ust_app_global_update(session, app);
 917                 }
 918         }
 919 end:
 920         return retval;
 921 }
 922
 923 /*
 924  * Called with session lock held.
 925  */
 926 ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
 927                 int32_t **_pids)
 928 {
 929         struct ust_pid_tracker_node *tracker_node;
 930         struct lttng_ht_iter iter;
 931         unsigned long count, i = 0;
 932         long approx[2];
 933         int32_t *pids;
 934         int ret = 0;
 935
 936         if (!session->pid_tracker.ht) {
 937                 /* Tracker disabled. Set first entry to -1. */
 938                 pids = zmalloc(sizeof(*pids));
 939                 if (!pids) {
 940                         ret = -1;
 941                         goto end;
 942                 }
 943                 pids[0] = -1;
 944                 *_pids = pids;
 945                 return 1;
 946         }
 947
 948         rcu_read_lock();
 949         cds_lfht_count_nodes(session->pid_tracker.ht->ht,
 950                 &approx[0], &count, &approx[1]);
 951         pids = zmalloc(sizeof(*pids) * count);
 952         if (!pids) {
 953                 ret = -1;
 954                 goto end;
 955         }
 956         cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
 957                         &iter.iter, tracker_node, node.node) {
 958                 pids[i++] = tracker_node->node.key;
 959         }
 960         *_pids = pids;
 961         ret = count;
 962 end:
 963         rcu_read_unlock();
 964         return ret;
 965 }
 966
 967 /*
 968  * RCU safe free context structure.
 969  */
 970 static void destroy_context_rcu(struct rcu_head *head)
 971 {
 972         struct lttng_ht_node_ulong *node =
 973                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 974         struct ltt_ust_context *ctx =
 975                 caa_container_of(node, struct ltt_ust_context, node);
 976
 977         trace_ust_destroy_context(ctx);
 978 }
 979
 980 /*
 981  * Cleanup UST context hash table.
 982  */
 983 static void destroy_contexts(struct lttng_ht *ht)
 984 {
 985         int ret;
 986         struct lttng_ht_node_ulong *node;
 987         struct lttng_ht_iter iter;
 988         struct ltt_ust_context *ctx;
 989
 990         assert(ht);
 991
 992         rcu_read_lock();
 993         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
 994                 /* Remove from ordered list. */
 995                 ctx = caa_container_of(node, struct ltt_ust_context, node);
 996                 cds_list_del(&ctx->list);
 997                 /* Remove from channel's hash table. */
 998                 ret = lttng_ht_del(ht, &iter);
 999                 if (!ret) {
1000                         call_rcu(&node->head, destroy_context_rcu);
1001                 }
1002         }
1003         rcu_read_unlock();
1004
1005         ht_cleanup_push(ht);
1006 }
1007
1008 /*
1009  * Cleanup ust event structure.
1010  */
1011 void trace_ust_destroy_event(struct ltt_ust_event *event)
1012 {
1013         assert(event);
1014
1015         DBG2("Trace destroy UST event %s", event->attr.name);
1016         free(event->filter_expression);
1017         free(event->filter);
1018         free(event->exclusion);
1019         free(event);
1020 }
1021
1022 /*
1023  * Cleanup ust context structure.
1024  */
1025 void trace_ust_destroy_context(struct ltt_ust_context *ctx)
1026 {
1027         assert(ctx);
1028
1029         if (ctx->ctx.ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1030                 free(ctx->ctx.u.app_ctx.provider_name);
1031                 free(ctx->ctx.u.app_ctx.ctx_name);
1032         }
1033         free(ctx);
1034 }
1035
1036 /*
1037  * URCU intermediate call to complete destroy event.
1038  */
1039 static void destroy_event_rcu(struct rcu_head *head)
1040 {
1041         struct lttng_ht_node_str *node =
1042                 caa_container_of(head, struct lttng_ht_node_str, head);
1043         struct ltt_ust_event *event =
1044                 caa_container_of(node, struct ltt_ust_event, node);
1045
1046         trace_ust_destroy_event(event);
1047 }
1048
1049 /*
1050  * Cleanup UST events hashtable.
1051  */
1052 static void destroy_events(struct lttng_ht *events)
1053 {
1054         int ret;
1055         struct lttng_ht_node_str *node;
1056         struct lttng_ht_iter iter;
1057
1058         assert(events);
1059
1060         rcu_read_lock();
1061         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1062                 ret = lttng_ht_del(events, &iter);
1063                 assert(!ret);
1064                 call_rcu(&node->head, destroy_event_rcu);
1065         }
1066         rcu_read_unlock();
1067
1068         ht_cleanup_push(events);
1069 }
1070
1071 /*
1072  * Cleanup ust channel structure.
1073  *
1074  * Should _NOT_ be called with RCU read lock held.
1075  */
1076 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1077 {
1078         assert(channel);
1079
1080         DBG2("Trace destroy UST channel %s", channel->name);
1081
1082         free(channel);
1083 }
1084
1085 /*
1086  * URCU intermediate call to complete destroy channel.
1087  */
1088 static void destroy_channel_rcu(struct rcu_head *head)
1089 {
1090         struct lttng_ht_node_str *node =
1091                 caa_container_of(head, struct lttng_ht_node_str, head);
1092         struct ltt_ust_channel *channel =
1093                 caa_container_of(node, struct ltt_ust_channel, node);
1094
1095         _trace_ust_destroy_channel(channel);
1096 }
1097
1098 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1099 {
1100         /* Destroying all events of the channel */
1101         destroy_events(channel->events);
1102         /* Destroying all context of the channel */
1103         destroy_contexts(channel->ctx);
1104
1105         call_rcu(&channel->node.head, destroy_channel_rcu);
1106 }
1107
1108 /*
1109  * Remove an UST channel from a channel HT.
1110  */
1111 void trace_ust_delete_channel(struct lttng_ht *ht,
1112                 struct ltt_ust_channel *channel)
1113 {
1114         int ret;
1115         struct lttng_ht_iter iter;
1116
1117         assert(ht);
1118         assert(channel);
1119
1120         iter.iter.node = &channel->node.node;
1121         ret = lttng_ht_del(ht, &iter);
1122         assert(!ret);
1123 }
1124
1125 /*
1126  * Iterate over a hash table containing channels and cleanup safely.
1127  */
1128 static void destroy_channels(struct lttng_ht *channels)
1129 {
1130         struct lttng_ht_node_str *node;
1131         struct lttng_ht_iter iter;
1132
1133         assert(channels);
1134
1135         rcu_read_lock();
1136         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1137                 struct ltt_ust_channel *chan =
1138                         caa_container_of(node, struct ltt_ust_channel, node);
1139
1140                 trace_ust_delete_channel(channels, chan);
1141                 trace_ust_destroy_channel(chan);
1142         }
1143         rcu_read_unlock();
1144
1145         ht_cleanup_push(channels);
1146 }
1147
1148 /*
1149  * Cleanup UST global domain.
1150  */
1151 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1152 {
1153         assert(dom);
1154
1155         destroy_channels(dom->channels);
1156 }
1157
1158 /*
1159  * Cleanup ust session structure
1160  *
1161  * Should *NOT* be called with RCU read-side lock held.
1162  */
1163 void trace_ust_destroy_session(struct ltt_ust_session *session)
1164 {
1165         struct agent *agt;
1166         struct buffer_reg_uid *reg, *sreg;
1167         struct lttng_ht_iter iter;
1168
1169         assert(session);
1170
1171         DBG2("Trace UST destroy session %" PRIu64, session->id);
1172
1173         /* Cleaning up UST domain */
1174         destroy_domain_global(&session->domain_global);
1175
1176         rcu_read_lock();
1177         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1178                 int ret = lttng_ht_del(session->agents, &iter);
1179
1180                 assert(!ret);
1181                 agent_destroy(agt);
1182         }
1183         rcu_read_unlock();
1184
1185         ht_cleanup_push(session->agents);
1186
1187         /* Cleanup UID buffer registry object(s). */
1188         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1189                         lnode) {
1190                 cds_list_del(&reg->lnode);
1191                 buffer_reg_uid_remove(reg);
1192                 buffer_reg_uid_destroy(reg, session->consumer);
1193         }
1194
1195         consumer_output_put(session->consumer);
1196
1197         fini_pid_tracker(&session->pid_tracker);
1198
1199         free(session);
1200 }