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         case LTTNG_EVENT_CONTEXT_CGROUP_NS:
 567                 utype = LTTNG_UST_CONTEXT_CGROUP_NS;
 568                 break;
 569         case LTTNG_EVENT_CONTEXT_IPC_NS:
 570                 utype = LTTNG_UST_CONTEXT_IPC_NS;
 571                 break;
 572         case LTTNG_EVENT_CONTEXT_MNT_NS:
 573                 utype = LTTNG_UST_CONTEXT_MNT_NS;
 574                 break;
 575         case LTTNG_EVENT_CONTEXT_NET_NS:
 576                 utype = LTTNG_UST_CONTEXT_NET_NS;
 577                 break;
 578         case LTTNG_EVENT_CONTEXT_PID_NS:
 579                 utype = LTTNG_UST_CONTEXT_PID_NS;
 580                 break;
 581         case LTTNG_EVENT_CONTEXT_USER_NS:
 582                 utype = LTTNG_UST_CONTEXT_USER_NS;
 583                 break;
 584         case LTTNG_EVENT_CONTEXT_UTS_NS:
 585                 utype = LTTNG_UST_CONTEXT_UTS_NS;
 586                 break;
 587         default:
 588                 utype = -1;
 589                 break;
 590         }
 591         return utype;
 592 }
 593
 594 /*
 595  * Return 1 if contexts match, 0 otherwise.
 596  */
 597 int trace_ust_match_context(struct ltt_ust_context *uctx,
 598                 struct lttng_event_context *ctx)
 599 {
 600         int utype;
 601
 602         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 603         if (utype < 0) {
 604                 return 0;
 605         }
 606         if (uctx->ctx.ctx != utype) {
 607                 return 0;
 608         }
 609         switch (utype) {
 610         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 611                 if (uctx->ctx.u.perf_counter.type
 612                                 != ctx->u.perf_counter.type) {
 613                         return 0;
 614                 }
 615                 if (uctx->ctx.u.perf_counter.config
 616                                 != ctx->u.perf_counter.config) {
 617                         return 0;
 618                 }
 619                 if (strncmp(uctx->ctx.u.perf_counter.name,
 620                                 ctx->u.perf_counter.name,
 621                                 LTTNG_UST_SYM_NAME_LEN)) {
 622                         return 0;
 623                 }
 624                 break;
 625         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 626                 assert(uctx->ctx.u.app_ctx.provider_name);
 627                 assert(uctx->ctx.u.app_ctx.ctx_name);
 628                 if (strcmp(uctx->ctx.u.app_ctx.provider_name,
 629                                 ctx->u.app_ctx.provider_name) ||
 630                                 strcmp(uctx->ctx.u.app_ctx.ctx_name,
 631                                 ctx->u.app_ctx.ctx_name)) {
 632                         return 0;
 633                 }
 634         default:
 635                 break;
 636
 637         }
 638         return 1;
 639 }
 640
 641 /*
 642  * Allocate and initialize an UST context.
 643  *
 644  * Return pointer to structure or NULL.
 645  */
 646 struct ltt_ust_context *trace_ust_create_context(
 647                 struct lttng_event_context *ctx)
 648 {
 649         struct ltt_ust_context *uctx = NULL;
 650         int utype;
 651
 652         assert(ctx);
 653
 654         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 655         if (utype < 0) {
 656                 ERR("Invalid UST context");
 657                 goto end;
 658         }
 659
 660         uctx = zmalloc(sizeof(struct ltt_ust_context));
 661         if (!uctx) {
 662                 PERROR("zmalloc ltt_ust_context");
 663                 goto end;
 664         }
 665
 666         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 667         switch (utype) {
 668         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 669                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 670                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 671                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 672                                 LTTNG_UST_SYM_NAME_LEN);
 673                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 674                 break;
 675         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 676         {
 677                 char *provider_name = NULL, *ctx_name = NULL;
 678
 679                 provider_name = strdup(ctx->u.app_ctx.provider_name);
 680                 if (!provider_name) {
 681                         goto error;
 682                 }
 683                 uctx->ctx.u.app_ctx.provider_name = provider_name;
 684
 685                 ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 686                 if (!ctx_name) {
 687                         goto error;
 688                 }
 689                 uctx->ctx.u.app_ctx.ctx_name = ctx_name;
 690                 break;
 691         }
 692         default:
 693                 break;
 694         }
 695         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 696 end:
 697         return uctx;
 698 error:
 699         trace_ust_destroy_context(uctx);
 700         return NULL;
 701 }
 702
 703 static
 704 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 705 {
 706         struct ust_pid_tracker_node *tracker_node =
 707                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 708         free(tracker_node);
 709 }
 710
 711 static
 712 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 713 {
 714
 715         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 716 }
 717
 718 static
 719 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 720 {
 721         int ret = 0;
 722
 723         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 724         if (!pid_tracker->ht) {
 725                 ret = -1;
 726                 goto end;
 727         }
 728
 729 end:
 730         return ret;
 731 }
 732
 733 /*
 734  * Teardown pid tracker content, but don't free pid_tracker object.
 735  */
 736 static
 737 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 738 {
 739         struct ust_pid_tracker_node *tracker_node;
 740         struct lttng_ht_iter iter;
 741
 742         if (!pid_tracker->ht) {
 743                 return;
 744         }
 745         rcu_read_lock();
 746         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 747                         &iter.iter, tracker_node, node.node) {
 748                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 749
 750                 assert(!ret);
 751                 destroy_pid_tracker_node(tracker_node);
 752         }
 753         rcu_read_unlock();
 754         ht_cleanup_push(pid_tracker->ht);
 755         pid_tracker->ht = NULL;
 756 }
 757
 758 static
 759 struct ust_pid_tracker_node *pid_tracker_lookup(
 760                 struct ust_pid_tracker *pid_tracker, int pid,
 761                 struct lttng_ht_iter *iter)
 762 {
 763         unsigned long _pid = (unsigned long) pid;
 764         struct lttng_ht_node_ulong *node;
 765
 766         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 767         node = lttng_ht_iter_get_node_ulong(iter);
 768         if (node) {
 769                 return caa_container_of(node, struct ust_pid_tracker_node,
 770                         node);
 771         } else {
 772                 return NULL;
 773         }
 774 }
 775
 776 static
 777 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 778 {
 779         int retval = LTTNG_OK;
 780         struct ust_pid_tracker_node *tracker_node;
 781         struct lttng_ht_iter iter;
 782
 783         if (pid < 0) {
 784                 retval = LTTNG_ERR_INVALID;
 785                 goto end;
 786         }
 787         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 788         if (tracker_node) {
 789                 /* Already exists. */
 790                 retval = LTTNG_ERR_PID_TRACKED;
 791                 goto end;
 792         }
 793         tracker_node = zmalloc(sizeof(*tracker_node));
 794         if (!tracker_node) {
 795                 retval = LTTNG_ERR_NOMEM;
 796                 goto end;
 797         }
 798         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 799         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 800 end:
 801         return retval;
 802 }
 803
 804 static
 805 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 806 {
 807         int retval = LTTNG_OK, ret;
 808         struct ust_pid_tracker_node *tracker_node;
 809         struct lttng_ht_iter iter;
 810
 811         if (pid < 0) {
 812                 retval = LTTNG_ERR_INVALID;
 813                 goto end;
 814         }
 815         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 816         if (!tracker_node) {
 817                 /* Not found */
 818                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 819                 goto end;
 820         }
 821         ret = lttng_ht_del(pid_tracker->ht, &iter);
 822         assert(!ret);
 823
 824         destroy_pid_tracker_node(tracker_node);
 825 end:
 826         return retval;
 827 }
 828
 829 /*
 830  * The session lock is held when calling this function.
 831  */
 832 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 833 {
 834         struct lttng_ht_iter iter;
 835
 836         if (!session->pid_tracker.ht) {
 837                 return 1;
 838         }
 839         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 840                 return 1;
 841         }
 842         return 0;
 843 }
 844
 845 /*
 846  * Called with the session lock held.
 847  */
 848 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 849 {
 850         int retval = LTTNG_OK;
 851         bool should_update_apps = false;
 852
 853         if (pid == -1) {
 854                 /* Track all pids: destroy tracker if exists. */
 855                 if (session->pid_tracker.ht) {
 856                         fini_pid_tracker(&session->pid_tracker);
 857                         /* Ensure all apps have session. */
 858                         should_update_apps = true;
 859                 }
 860         } else {
 861                 int ret;
 862
 863                 if (!session->pid_tracker.ht) {
 864                         /* Create tracker. */
 865                         if (init_pid_tracker(&session->pid_tracker)) {
 866                                 ERR("Error initializing PID tracker");
 867                                 retval = LTTNG_ERR_NOMEM;
 868                                 goto end;
 869                         }
 870                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 871                         if (ret != LTTNG_OK) {
 872                                 retval = ret;
 873                                 fini_pid_tracker(&session->pid_tracker);
 874                                 goto end;
 875                         }
 876                         /* Remove all apps from session except pid. */
 877                         should_update_apps = true;
 878                 } else {
 879                         struct ust_app *app;
 880
 881                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 882                         if (ret != LTTNG_OK) {
 883                                 retval = ret;
 884                                 goto end;
 885                         }
 886                         /* Add session to application */
 887                         app = ust_app_find_by_pid(pid);
 888                         if (app) {
 889                                 should_update_apps = true;
 890                         }
 891                 }
 892         }
 893         if (should_update_apps && session->active) {
 894                 ust_app_global_update_all(session);
 895         }
 896 end:
 897         return retval;
 898 }
 899
 900 /*
 901  * Called with the session lock held.
 902  */
 903 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 904 {
 905         int retval = LTTNG_OK;
 906
 907         if (pid == -1) {
 908                 /* Create empty tracker, replace old tracker. */
 909                 struct ust_pid_tracker tmp_tracker;
 910
 911                 tmp_tracker = session->pid_tracker;
 912                 if (init_pid_tracker(&session->pid_tracker)) {
 913                         ERR("Error initializing PID tracker");
 914                         retval = LTTNG_ERR_NOMEM;
 915                         /* Rollback operation. */
 916                         session->pid_tracker = tmp_tracker;
 917                         goto end;
 918                 }
 919                 fini_pid_tracker(&tmp_tracker);
 920
 921                 /* Remove session from all applications */
 922                 ust_app_global_update_all(session);
 923         } else {
 924                 int ret;
 925                 struct ust_app *app;
 926
 927                 if (!session->pid_tracker.ht) {
 928                         /* No PID being tracked. */
 929                         retval = LTTNG_ERR_PID_NOT_TRACKED;
 930                         goto end;
 931                 }
 932                 /* Remove PID from tracker */
 933                 ret = pid_tracker_del_pid(&session->pid_tracker, pid);
 934                 if (ret != LTTNG_OK) {
 935                         retval = ret;
 936                         goto end;
 937                 }
 938                 /* Remove session from application. */
 939                 app = ust_app_find_by_pid(pid);
 940                 if (app) {
 941                         ust_app_global_update(session, app);
 942                 }
 943         }
 944 end:
 945         return retval;
 946 }
 947
 948 /*
 949  * Called with session lock held.
 950  */
 951 ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
 952                 int32_t **_pids)
 953 {
 954         struct ust_pid_tracker_node *tracker_node;
 955         struct lttng_ht_iter iter;
 956         unsigned long count, i = 0;
 957         long approx[2];
 958         int32_t *pids;
 959         int ret = 0;
 960
 961         if (!session->pid_tracker.ht) {
 962                 /* Tracker disabled. Set first entry to -1. */
 963                 pids = zmalloc(sizeof(*pids));
 964                 if (!pids) {
 965                         ret = -1;
 966                         goto end;
 967                 }
 968                 pids[0] = -1;
 969                 *_pids = pids;
 970                 return 1;
 971         }
 972
 973         rcu_read_lock();
 974         cds_lfht_count_nodes(session->pid_tracker.ht->ht,
 975                 &approx[0], &count, &approx[1]);
 976         pids = zmalloc(sizeof(*pids) * count);
 977         if (!pids) {
 978                 ret = -1;
 979                 goto end;
 980         }
 981         cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
 982                         &iter.iter, tracker_node, node.node) {
 983                 pids[i++] = tracker_node->node.key;
 984         }
 985         *_pids = pids;
 986         ret = count;
 987 end:
 988         rcu_read_unlock();
 989         return ret;
 990 }
 991
 992 /*
 993  * RCU safe free context structure.
 994  */
 995 static void destroy_context_rcu(struct rcu_head *head)
 996 {
 997         struct lttng_ht_node_ulong *node =
 998                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 999         struct ltt_ust_context *ctx =
1000                 caa_container_of(node, struct ltt_ust_context, node);
1001
1002         trace_ust_destroy_context(ctx);
1003 }
1004
1005 /*
1006  * Cleanup UST context hash table.
1007  */
1008 static void destroy_contexts(struct lttng_ht *ht)
1009 {
1010         int ret;
1011         struct lttng_ht_node_ulong *node;
1012         struct lttng_ht_iter iter;
1013         struct ltt_ust_context *ctx;
1014
1015         assert(ht);
1016
1017         rcu_read_lock();
1018         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
1019                 /* Remove from ordered list. */
1020                 ctx = caa_container_of(node, struct ltt_ust_context, node);
1021                 cds_list_del(&ctx->list);
1022                 /* Remove from channel's hash table. */
1023                 ret = lttng_ht_del(ht, &iter);
1024                 if (!ret) {
1025                         call_rcu(&node->head, destroy_context_rcu);
1026                 }
1027         }
1028         rcu_read_unlock();
1029
1030         ht_cleanup_push(ht);
1031 }
1032
1033 /*
1034  * Cleanup ust event structure.
1035  */
1036 void trace_ust_destroy_event(struct ltt_ust_event *event)
1037 {
1038         assert(event);
1039
1040         DBG2("Trace destroy UST event %s", event->attr.name);
1041         free(event->filter_expression);
1042         free(event->filter);
1043         free(event->exclusion);
1044         free(event);
1045 }
1046
1047 /*
1048  * Cleanup ust context structure.
1049  */
1050 void trace_ust_destroy_context(struct ltt_ust_context *ctx)
1051 {
1052         assert(ctx);
1053
1054         if (ctx->ctx.ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1055                 free(ctx->ctx.u.app_ctx.provider_name);
1056                 free(ctx->ctx.u.app_ctx.ctx_name);
1057         }
1058         free(ctx);
1059 }
1060
1061 /*
1062  * URCU intermediate call to complete destroy event.
1063  */
1064 static void destroy_event_rcu(struct rcu_head *head)
1065 {
1066         struct lttng_ht_node_str *node =
1067                 caa_container_of(head, struct lttng_ht_node_str, head);
1068         struct ltt_ust_event *event =
1069                 caa_container_of(node, struct ltt_ust_event, node);
1070
1071         trace_ust_destroy_event(event);
1072 }
1073
1074 /*
1075  * Cleanup UST events hashtable.
1076  */
1077 static void destroy_events(struct lttng_ht *events)
1078 {
1079         int ret;
1080         struct lttng_ht_node_str *node;
1081         struct lttng_ht_iter iter;
1082
1083         assert(events);
1084
1085         rcu_read_lock();
1086         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1087                 ret = lttng_ht_del(events, &iter);
1088                 assert(!ret);
1089                 call_rcu(&node->head, destroy_event_rcu);
1090         }
1091         rcu_read_unlock();
1092
1093         ht_cleanup_push(events);
1094 }
1095
1096 /*
1097  * Cleanup ust channel structure.
1098  *
1099  * Should _NOT_ be called with RCU read lock held.
1100  */
1101 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1102 {
1103         assert(channel);
1104
1105         DBG2("Trace destroy UST channel %s", channel->name);
1106
1107         free(channel);
1108 }
1109
1110 /*
1111  * URCU intermediate call to complete destroy channel.
1112  */
1113 static void destroy_channel_rcu(struct rcu_head *head)
1114 {
1115         struct lttng_ht_node_str *node =
1116                 caa_container_of(head, struct lttng_ht_node_str, head);
1117         struct ltt_ust_channel *channel =
1118                 caa_container_of(node, struct ltt_ust_channel, node);
1119
1120         _trace_ust_destroy_channel(channel);
1121 }
1122
1123 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1124 {
1125         /* Destroying all events of the channel */
1126         destroy_events(channel->events);
1127         /* Destroying all context of the channel */
1128         destroy_contexts(channel->ctx);
1129
1130         call_rcu(&channel->node.head, destroy_channel_rcu);
1131 }
1132
1133 /*
1134  * Remove an UST channel from a channel HT.
1135  */
1136 void trace_ust_delete_channel(struct lttng_ht *ht,
1137                 struct ltt_ust_channel *channel)
1138 {
1139         int ret;
1140         struct lttng_ht_iter iter;
1141
1142         assert(ht);
1143         assert(channel);
1144
1145         iter.iter.node = &channel->node.node;
1146         ret = lttng_ht_del(ht, &iter);
1147         assert(!ret);
1148 }
1149
1150 /*
1151  * Iterate over a hash table containing channels and cleanup safely.
1152  */
1153 static void destroy_channels(struct lttng_ht *channels)
1154 {
1155         struct lttng_ht_node_str *node;
1156         struct lttng_ht_iter iter;
1157
1158         assert(channels);
1159
1160         rcu_read_lock();
1161         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1162                 struct ltt_ust_channel *chan =
1163                         caa_container_of(node, struct ltt_ust_channel, node);
1164
1165                 trace_ust_delete_channel(channels, chan);
1166                 trace_ust_destroy_channel(chan);
1167         }
1168         rcu_read_unlock();
1169
1170         ht_cleanup_push(channels);
1171 }
1172
1173 /*
1174  * Cleanup UST global domain.
1175  */
1176 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1177 {
1178         assert(dom);
1179
1180         destroy_channels(dom->channels);
1181 }
1182
1183 /*
1184  * Cleanup ust session structure
1185  *
1186  * Should *NOT* be called with RCU read-side lock held.
1187  */
1188 void trace_ust_destroy_session(struct ltt_ust_session *session)
1189 {
1190         struct agent *agt;
1191         struct buffer_reg_uid *reg, *sreg;
1192         struct lttng_ht_iter iter;
1193
1194         assert(session);
1195
1196         DBG2("Trace UST destroy session %" PRIu64, session->id);
1197
1198         /* Cleaning up UST domain */
1199         destroy_domain_global(&session->domain_global);
1200
1201         rcu_read_lock();
1202         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1203                 int ret = lttng_ht_del(session->agents, &iter);
1204
1205                 assert(!ret);
1206                 agent_destroy(agt);
1207         }
1208         rcu_read_unlock();
1209
1210         ht_cleanup_push(session->agents);
1211
1212         /* Cleanup UID buffer registry object(s). */
1213         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1214                         lnode) {
1215                 cds_list_del(&reg->lnode);
1216                 buffer_reg_uid_remove(reg);
1217                 buffer_reg_uid_destroy(reg, session->consumer);
1218         }
1219
1220         consumer_output_put(session->consumer);
1221
1222         fini_pid_tracker(&session->pid_tracker);
1223
1224         free(session);
1225 }