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 pointer to structure or NULL.
 439  */
 440 struct ltt_ust_event *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 {
 446         struct ltt_ust_event *lue;
 447
 448         assert(ev);
 449
 450         if (exclusion && validate_exclusion(exclusion)) {
 451                 goto error;
 452         }
 453
 454         lue = zmalloc(sizeof(struct ltt_ust_event));
 455         if (lue == NULL) {
 456                 PERROR("ust event zmalloc");
 457                 goto error;
 458         }
 459
 460         lue->internal = internal_event;
 461
 462         switch (ev->type) {
 463         case LTTNG_EVENT_PROBE:
 464                 lue->attr.instrumentation = LTTNG_UST_PROBE;
 465                 break;
 466         case LTTNG_EVENT_FUNCTION:
 467                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 468                 break;
 469         case LTTNG_EVENT_FUNCTION_ENTRY:
 470                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 471                 break;
 472         case LTTNG_EVENT_TRACEPOINT:
 473                 lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 474                 break;
 475         default:
 476                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 477                 goto error_free_event;
 478         }
 479
 480         /* Copy event name */
 481         strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 482         lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 483
 484         switch (ev->loglevel_type) {
 485         case LTTNG_EVENT_LOGLEVEL_ALL:
 486                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 487                 lue->attr.loglevel = -1;        /* Force to -1 */
 488                 break;
 489         case LTTNG_EVENT_LOGLEVEL_RANGE:
 490                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 491                 lue->attr.loglevel = ev->loglevel;
 492                 break;
 493         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 494                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 495                 lue->attr.loglevel = ev->loglevel;
 496                 break;
 497         default:
 498                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 499                 goto error_free_event;
 500         }
 501
 502         /* Same layout. */
 503         lue->filter_expression = filter_expression;
 504         lue->filter = filter;
 505         lue->exclusion = exclusion;
 506
 507         /* Init node */
 508         lttng_ht_node_init_str(&lue->node, lue->attr.name);
 509
 510         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 511                 lue->attr.name, lue->attr.loglevel_type,
 512                 lue->attr.loglevel);
 513
 514         return lue;
 515
 516 error_free_event:
 517         free(lue);
 518 error:
 519         free(filter_expression);
 520         free(filter);
 521         free(exclusion);
 522         return NULL;
 523 }
 524
 525 static
 526 int trace_ust_context_type_event_to_ust(
 527                 enum lttng_event_context_type type)
 528 {
 529         int utype;
 530
 531         switch (type) {
 532         case LTTNG_EVENT_CONTEXT_VTID:
 533                 utype = LTTNG_UST_CONTEXT_VTID;
 534                 break;
 535         case LTTNG_EVENT_CONTEXT_VPID:
 536                 utype = LTTNG_UST_CONTEXT_VPID;
 537                 break;
 538         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 539                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 540                 break;
 541         case LTTNG_EVENT_CONTEXT_PROCNAME:
 542                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 543                 break;
 544         case LTTNG_EVENT_CONTEXT_IP:
 545                 utype = LTTNG_UST_CONTEXT_IP;
 546                 break;
 547         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 548                 if (!ustctl_has_perf_counters()) {
 549                         utype = -1;
 550                         WARN("Perf counters not implemented in UST");
 551                 } else {
 552                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 553                 }
 554                 break;
 555         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
 556                 utype = LTTNG_UST_CONTEXT_APP_CONTEXT;
 557                 break;
 558         default:
 559                 utype = -1;
 560                 break;
 561         }
 562         return utype;
 563 }
 564
 565 /*
 566  * Return 1 if contexts match, 0 otherwise.
 567  */
 568 int trace_ust_match_context(struct ltt_ust_context *uctx,
 569                 struct lttng_event_context *ctx)
 570 {
 571         int utype;
 572
 573         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 574         if (utype < 0) {
 575                 return 0;
 576         }
 577         if (uctx->ctx.ctx != utype) {
 578                 return 0;
 579         }
 580         switch (utype) {
 581         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 582                 if (uctx->ctx.u.perf_counter.type
 583                                 != ctx->u.perf_counter.type) {
 584                         return 0;
 585                 }
 586                 if (uctx->ctx.u.perf_counter.config
 587                                 != ctx->u.perf_counter.config) {
 588                         return 0;
 589                 }
 590                 if (strncmp(uctx->ctx.u.perf_counter.name,
 591                                 ctx->u.perf_counter.name,
 592                                 LTTNG_UST_SYM_NAME_LEN)) {
 593                         return 0;
 594                 }
 595                 break;
 596         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 597                 assert(uctx->ctx.u.app_ctx.provider_name);
 598                 assert(uctx->ctx.u.app_ctx.ctx_name);
 599                 if (strcmp(uctx->ctx.u.app_ctx.provider_name,
 600                                 ctx->u.app_ctx.provider_name) ||
 601                                 strcmp(uctx->ctx.u.app_ctx.ctx_name,
 602                                 ctx->u.app_ctx.ctx_name)) {
 603                         return 0;
 604                 }
 605         default:
 606                 break;
 607
 608         }
 609         return 1;
 610 }
 611
 612 /*
 613  * Allocate and initialize an UST context.
 614  *
 615  * Return pointer to structure or NULL.
 616  */
 617 struct ltt_ust_context *trace_ust_create_context(
 618                 struct lttng_event_context *ctx)
 619 {
 620         struct ltt_ust_context *uctx = NULL;
 621         int utype;
 622
 623         assert(ctx);
 624
 625         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 626         if (utype < 0) {
 627                 ERR("Invalid UST context");
 628                 goto end;
 629         }
 630
 631         uctx = zmalloc(sizeof(struct ltt_ust_context));
 632         if (!uctx) {
 633                 PERROR("zmalloc ltt_ust_context");
 634                 goto end;
 635         }
 636
 637         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 638         switch (utype) {
 639         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 640                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 641                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 642                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 643                                 LTTNG_UST_SYM_NAME_LEN);
 644                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 645                 break;
 646         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 647         {
 648                 char *provider_name = NULL, *ctx_name = NULL;
 649
 650                 provider_name = strdup(ctx->u.app_ctx.provider_name);
 651                 if (!provider_name) {
 652                         goto error;
 653                 }
 654                 uctx->ctx.u.app_ctx.provider_name = provider_name;
 655
 656                 ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 657                 if (!ctx_name) {
 658                         goto error;
 659                 }
 660                 uctx->ctx.u.app_ctx.ctx_name = ctx_name;
 661                 break;
 662         }
 663         default:
 664                 break;
 665         }
 666         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 667 end:
 668         return uctx;
 669 error:
 670         trace_ust_destroy_context(uctx);
 671         return NULL;
 672 }
 673
 674 static
 675 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 676 {
 677         struct ust_pid_tracker_node *tracker_node =
 678                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 679         free(tracker_node);
 680 }
 681
 682 static
 683 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 684 {
 685
 686         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 687 }
 688
 689 static
 690 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 691 {
 692         int ret = 0;
 693
 694         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 695         if (!pid_tracker->ht) {
 696                 ret = -1;
 697                 goto end;
 698         }
 699
 700 end:
 701         return ret;
 702 }
 703
 704 /*
 705  * Teardown pid tracker content, but don't free pid_tracker object.
 706  */
 707 static
 708 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 709 {
 710         struct ust_pid_tracker_node *tracker_node;
 711         struct lttng_ht_iter iter;
 712
 713         if (!pid_tracker->ht) {
 714                 return;
 715         }
 716         rcu_read_lock();
 717         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 718                         &iter.iter, tracker_node, node.node) {
 719                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 720
 721                 assert(!ret);
 722                 destroy_pid_tracker_node(tracker_node);
 723         }
 724         rcu_read_unlock();
 725         ht_cleanup_push(pid_tracker->ht);
 726         pid_tracker->ht = NULL;
 727 }
 728
 729 static
 730 struct ust_pid_tracker_node *pid_tracker_lookup(
 731                 struct ust_pid_tracker *pid_tracker, int pid,
 732                 struct lttng_ht_iter *iter)
 733 {
 734         unsigned long _pid = (unsigned long) pid;
 735         struct lttng_ht_node_ulong *node;
 736
 737         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 738         node = lttng_ht_iter_get_node_ulong(iter);
 739         if (node) {
 740                 return caa_container_of(node, struct ust_pid_tracker_node,
 741                         node);
 742         } else {
 743                 return NULL;
 744         }
 745 }
 746
 747 static
 748 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 749 {
 750         int retval = LTTNG_OK;
 751         struct ust_pid_tracker_node *tracker_node;
 752         struct lttng_ht_iter iter;
 753
 754         if (pid < 0) {
 755                 retval = LTTNG_ERR_INVALID;
 756                 goto end;
 757         }
 758         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 759         if (tracker_node) {
 760                 /* Already exists. */
 761                 retval = LTTNG_ERR_PID_TRACKED;
 762                 goto end;
 763         }
 764         tracker_node = zmalloc(sizeof(*tracker_node));
 765         if (!tracker_node) {
 766                 retval = LTTNG_ERR_NOMEM;
 767                 goto end;
 768         }
 769         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 770         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 771 end:
 772         return retval;
 773 }
 774
 775 static
 776 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 777 {
 778         int retval = LTTNG_OK, ret;
 779         struct ust_pid_tracker_node *tracker_node;
 780         struct lttng_ht_iter iter;
 781
 782         if (pid < 0) {
 783                 retval = LTTNG_ERR_INVALID;
 784                 goto end;
 785         }
 786         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 787         if (!tracker_node) {
 788                 /* Not found */
 789                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 790                 goto end;
 791         }
 792         ret = lttng_ht_del(pid_tracker->ht, &iter);
 793         assert(!ret);
 794
 795         destroy_pid_tracker_node(tracker_node);
 796 end:
 797         return retval;
 798 }
 799
 800 /*
 801  * The session lock is held when calling this function.
 802  */
 803 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 804 {
 805         struct lttng_ht_iter iter;
 806
 807         if (!session->pid_tracker.ht) {
 808                 return 1;
 809         }
 810         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 811                 return 1;
 812         }
 813         return 0;
 814 }
 815
 816 /*
 817  * Called with the session lock held.
 818  */
 819 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 820 {
 821         int retval = LTTNG_OK;
 822
 823         if (pid == -1) {
 824                 /* Track all pids: destroy tracker if exists. */
 825                 if (session->pid_tracker.ht) {
 826                         fini_pid_tracker(&session->pid_tracker);
 827                         /* Ensure all apps have session. */
 828                         ust_app_global_update_all(session);
 829                 }
 830         } else {
 831                 int ret;
 832
 833                 if (!session->pid_tracker.ht) {
 834                         /* Create tracker. */
 835                         if (init_pid_tracker(&session->pid_tracker)) {
 836                                 ERR("Error initializing PID tracker");
 837                                 retval = LTTNG_ERR_NOMEM;
 838                                 goto end;
 839                         }
 840                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 841                         if (ret != LTTNG_OK) {
 842                                 retval = ret;
 843                                 fini_pid_tracker(&session->pid_tracker);
 844                                 goto end;
 845                         }
 846                         /* Remove all apps from session except pid. */
 847                         ust_app_global_update_all(session);
 848                 } else {
 849                         struct ust_app *app;
 850
 851                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 852                         if (ret != LTTNG_OK) {
 853                                 retval = ret;
 854                                 goto end;
 855                         }
 856                         /* Add session to application */
 857                         app = ust_app_find_by_pid(pid);
 858                         if (app) {
 859                                 ust_app_global_update(session, app);
 860                         }
 861                 }
 862         }
 863 end:
 864         return retval;
 865 }
 866
 867 /*
 868  * Called with the session lock held.
 869  */
 870 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 871 {
 872         int retval = LTTNG_OK;
 873
 874         if (pid == -1) {
 875                 /* Create empty tracker, replace old tracker. */
 876                 struct ust_pid_tracker tmp_tracker;
 877
 878                 tmp_tracker = session->pid_tracker;
 879                 if (init_pid_tracker(&session->pid_tracker)) {
 880                         ERR("Error initializing PID tracker");
 881                         retval = LTTNG_ERR_NOMEM;
 882                         /* Rollback operation. */
 883                         session->pid_tracker = tmp_tracker;
 884                         goto end;
 885                 }
 886                 fini_pid_tracker(&tmp_tracker);
 887
 888                 /* Remove session from all applications */
 889                 ust_app_global_update_all(session);
 890         } else {
 891                 int ret;
 892                 struct ust_app *app;
 893
 894                 if (!session->pid_tracker.ht) {
 895                         /* No PID being tracked. */
 896                         retval = LTTNG_ERR_PID_NOT_TRACKED;
 897                         goto end;
 898                 }
 899                 /* Remove PID from tracker */
 900                 ret = pid_tracker_del_pid(&session->pid_tracker, pid);
 901                 if (ret != LTTNG_OK) {
 902                         retval = ret;
 903                         goto end;
 904                 }
 905                 /* Remove session from application. */
 906                 app = ust_app_find_by_pid(pid);
 907                 if (app) {
 908                         ust_app_global_update(session, app);
 909                 }
 910         }
 911 end:
 912         return retval;
 913 }
 914
 915 /*
 916  * Called with session lock held.
 917  */
 918 ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
 919                 int32_t **_pids)
 920 {
 921         struct ust_pid_tracker_node *tracker_node;
 922         struct lttng_ht_iter iter;
 923         unsigned long count, i = 0;
 924         long approx[2];
 925         int32_t *pids;
 926         int ret = 0;
 927
 928         if (!session->pid_tracker.ht) {
 929                 /* Tracker disabled. Set first entry to -1. */
 930                 pids = zmalloc(sizeof(*pids));
 931                 if (!pids) {
 932                         ret = -1;
 933                         goto end;
 934                 }
 935                 pids[0] = -1;
 936                 *_pids = pids;
 937                 return 1;
 938         }
 939
 940         rcu_read_lock();
 941         cds_lfht_count_nodes(session->pid_tracker.ht->ht,
 942                 &approx[0], &count, &approx[1]);
 943         pids = zmalloc(sizeof(*pids) * count);
 944         if (!pids) {
 945                 ret = -1;
 946                 goto end;
 947         }
 948         cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
 949                         &iter.iter, tracker_node, node.node) {
 950                 pids[i++] = tracker_node->node.key;
 951         }
 952         *_pids = pids;
 953         ret = count;
 954 end:
 955         rcu_read_unlock();
 956         return ret;
 957 }
 958
 959 /*
 960  * RCU safe free context structure.
 961  */
 962 static void destroy_context_rcu(struct rcu_head *head)
 963 {
 964         struct lttng_ht_node_ulong *node =
 965                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 966         struct ltt_ust_context *ctx =
 967                 caa_container_of(node, struct ltt_ust_context, node);
 968
 969         trace_ust_destroy_context(ctx);
 970 }
 971
 972 /*
 973  * Cleanup UST context hash table.
 974  */
 975 static void destroy_contexts(struct lttng_ht *ht)
 976 {
 977         int ret;
 978         struct lttng_ht_node_ulong *node;
 979         struct lttng_ht_iter iter;
 980         struct ltt_ust_context *ctx;
 981
 982         assert(ht);
 983
 984         rcu_read_lock();
 985         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
 986                 /* Remove from ordered list. */
 987                 ctx = caa_container_of(node, struct ltt_ust_context, node);
 988                 cds_list_del(&ctx->list);
 989                 /* Remove from channel's hash table. */
 990                 ret = lttng_ht_del(ht, &iter);
 991                 if (!ret) {
 992                         call_rcu(&node->head, destroy_context_rcu);
 993                 }
 994         }
 995         rcu_read_unlock();
 996
 997         ht_cleanup_push(ht);
 998 }
 999
1000 /*
1001  * Cleanup ust event structure.
1002  */
1003 void trace_ust_destroy_event(struct ltt_ust_event *event)
1004 {
1005         assert(event);
1006
1007         DBG2("Trace destroy UST event %s", event->attr.name);
1008         free(event->filter_expression);
1009         free(event->filter);
1010         free(event->exclusion);
1011         free(event);
1012 }
1013
1014 /*
1015  * Cleanup ust context structure.
1016  */
1017 void trace_ust_destroy_context(struct ltt_ust_context *ctx)
1018 {
1019         assert(ctx);
1020
1021         if (ctx->ctx.ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1022                 free(ctx->ctx.u.app_ctx.provider_name);
1023                 free(ctx->ctx.u.app_ctx.ctx_name);
1024         }
1025         free(ctx);
1026 }
1027
1028 /*
1029  * URCU intermediate call to complete destroy event.
1030  */
1031 static void destroy_event_rcu(struct rcu_head *head)
1032 {
1033         struct lttng_ht_node_str *node =
1034                 caa_container_of(head, struct lttng_ht_node_str, head);
1035         struct ltt_ust_event *event =
1036                 caa_container_of(node, struct ltt_ust_event, node);
1037
1038         trace_ust_destroy_event(event);
1039 }
1040
1041 /*
1042  * Cleanup UST events hashtable.
1043  */
1044 static void destroy_events(struct lttng_ht *events)
1045 {
1046         int ret;
1047         struct lttng_ht_node_str *node;
1048         struct lttng_ht_iter iter;
1049
1050         assert(events);
1051
1052         rcu_read_lock();
1053         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1054                 ret = lttng_ht_del(events, &iter);
1055                 assert(!ret);
1056                 call_rcu(&node->head, destroy_event_rcu);
1057         }
1058         rcu_read_unlock();
1059
1060         ht_cleanup_push(events);
1061 }
1062
1063 /*
1064  * Cleanup ust channel structure.
1065  *
1066  * Should _NOT_ be called with RCU read lock held.
1067  */
1068 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1069 {
1070         assert(channel);
1071
1072         DBG2("Trace destroy UST channel %s", channel->name);
1073
1074         free(channel);
1075 }
1076
1077 /*
1078  * URCU intermediate call to complete destroy channel.
1079  */
1080 static void destroy_channel_rcu(struct rcu_head *head)
1081 {
1082         struct lttng_ht_node_str *node =
1083                 caa_container_of(head, struct lttng_ht_node_str, head);
1084         struct ltt_ust_channel *channel =
1085                 caa_container_of(node, struct ltt_ust_channel, node);
1086
1087         _trace_ust_destroy_channel(channel);
1088 }
1089
1090 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1091 {
1092         /* Destroying all events of the channel */
1093         destroy_events(channel->events);
1094         /* Destroying all context of the channel */
1095         destroy_contexts(channel->ctx);
1096
1097         call_rcu(&channel->node.head, destroy_channel_rcu);
1098 }
1099
1100 /*
1101  * Remove an UST channel from a channel HT.
1102  */
1103 void trace_ust_delete_channel(struct lttng_ht *ht,
1104                 struct ltt_ust_channel *channel)
1105 {
1106         int ret;
1107         struct lttng_ht_iter iter;
1108
1109         assert(ht);
1110         assert(channel);
1111
1112         iter.iter.node = &channel->node.node;
1113         ret = lttng_ht_del(ht, &iter);
1114         assert(!ret);
1115 }
1116
1117 /*
1118  * Iterate over a hash table containing channels and cleanup safely.
1119  */
1120 static void destroy_channels(struct lttng_ht *channels)
1121 {
1122         struct lttng_ht_node_str *node;
1123         struct lttng_ht_iter iter;
1124
1125         assert(channels);
1126
1127         rcu_read_lock();
1128         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1129                 struct ltt_ust_channel *chan =
1130                         caa_container_of(node, struct ltt_ust_channel, node);
1131
1132                 trace_ust_delete_channel(channels, chan);
1133                 trace_ust_destroy_channel(chan);
1134         }
1135         rcu_read_unlock();
1136
1137         ht_cleanup_push(channels);
1138 }
1139
1140 /*
1141  * Cleanup UST global domain.
1142  */
1143 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1144 {
1145         assert(dom);
1146
1147         destroy_channels(dom->channels);
1148 }
1149
1150 /*
1151  * Cleanup ust session structure
1152  *
1153  * Should *NOT* be called with RCU read-side lock held.
1154  */
1155 void trace_ust_destroy_session(struct ltt_ust_session *session)
1156 {
1157         struct agent *agt;
1158         struct buffer_reg_uid *reg, *sreg;
1159         struct lttng_ht_iter iter;
1160
1161         assert(session);
1162
1163         DBG2("Trace UST destroy session %" PRIu64, session->id);
1164
1165         /* Cleaning up UST domain */
1166         destroy_domain_global(&session->domain_global);
1167
1168         rcu_read_lock();
1169         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1170                 int ret = lttng_ht_del(session->agents, &iter);
1171
1172                 assert(!ret);
1173                 agent_destroy(agt);
1174         }
1175         rcu_read_unlock();
1176
1177         ht_cleanup_push(session->agents);
1178
1179         /* Cleanup UID buffer registry object(s). */
1180         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1181                         lnode) {
1182                 cds_list_del(&reg->lnode);
1183                 buffer_reg_uid_remove(reg);
1184                 buffer_reg_uid_destroy(reg, session->consumer);
1185         }
1186
1187         consumer_output_put(session->consumer);
1188
1189         fini_pid_tracker(&session->pid_tracker);
1190
1191         free(session);
1192 }