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 =
 360                         ((struct lttng_channel_extended *) chan->attr.extended.ptr)->monitor_timer_interval;
 361
 362         /* Translate to UST output enum */
 363         switch (luc->attr.output) {
 364         default:
 365                 luc->attr.output = LTTNG_UST_MMAP;
 366                 break;
 367         }
 368
 369         /*
 370          * If we receive an empty string for channel name, it means the
 371          * default channel name is requested.
 372          */
 373         if (chan->name[0] == '\0') {
 374                 strncpy(luc->name, DEFAULT_CHANNEL_NAME, sizeof(luc->name));
 375         } else {
 376                 /* Copy channel name */
 377                 strncpy(luc->name, chan->name, sizeof(luc->name));
 378         }
 379         luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 380
 381         /* Init node */
 382         lttng_ht_node_init_str(&luc->node, luc->name);
 383         CDS_INIT_LIST_HEAD(&luc->ctx_list);
 384
 385         /* Alloc hash tables */
 386         luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 387         luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 388
 389         /* On-disk circular buffer parameters */
 390         luc->tracefile_size = chan->attr.tracefile_size;
 391         luc->tracefile_count = chan->attr.tracefile_count;
 392
 393         DBG2("Trace UST channel %s created", luc->name);
 394
 395 error:
 396         return luc;
 397 }
 398
 399 /*
 400  * Validates an exclusion list.
 401  *
 402  * Returns 0 if valid, negative value if invalid.
 403  */
 404 static int validate_exclusion(struct lttng_event_exclusion *exclusion)
 405 {
 406         size_t i;
 407         int ret = 0;
 408
 409         assert(exclusion);
 410
 411         for (i = 0; i < exclusion->count; ++i) {
 412                 size_t j;
 413                 const char *name_a =
 414                         LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, i);
 415
 416                 for (j = 0; j < i; ++j) {
 417                         const char *name_b =
 418                                 LTTNG_EVENT_EXCLUSION_NAME_AT(exclusion, j);
 419
 420                         if (!strncmp(name_a, name_b, LTTNG_SYMBOL_NAME_LEN)) {
 421                                 /* Match! */
 422                                 ret = -1;
 423                                 goto end;
 424                         }
 425                 }
 426         }
 427
 428 end:
 429         return ret;
 430 }
 431
 432 /*
 433  * Allocate and initialize a ust event. Set name and event type.
 434  * We own filter_expression, filter, and exclusion.
 435  *
 436  * Return pointer to structure or NULL.
 437  */
 438 struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev,
 439                 char *filter_expression,
 440                 struct lttng_filter_bytecode *filter,
 441                 struct lttng_event_exclusion *exclusion,
 442                 bool internal_event)
 443 {
 444         struct ltt_ust_event *lue;
 445
 446         assert(ev);
 447
 448         if (exclusion && validate_exclusion(exclusion)) {
 449                 goto error;
 450         }
 451
 452         lue = zmalloc(sizeof(struct ltt_ust_event));
 453         if (lue == NULL) {
 454                 PERROR("ust event zmalloc");
 455                 goto error;
 456         }
 457
 458         lue->internal = internal_event;
 459
 460         switch (ev->type) {
 461         case LTTNG_EVENT_PROBE:
 462                 lue->attr.instrumentation = LTTNG_UST_PROBE;
 463                 break;
 464         case LTTNG_EVENT_FUNCTION:
 465                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 466                 break;
 467         case LTTNG_EVENT_FUNCTION_ENTRY:
 468                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 469                 break;
 470         case LTTNG_EVENT_TRACEPOINT:
 471                 lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 472                 break;
 473         default:
 474                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 475                 goto error_free_event;
 476         }
 477
 478         /* Copy event name */
 479         strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 480         lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 481
 482         switch (ev->loglevel_type) {
 483         case LTTNG_EVENT_LOGLEVEL_ALL:
 484                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 485                 lue->attr.loglevel = -1;        /* Force to -1 */
 486                 break;
 487         case LTTNG_EVENT_LOGLEVEL_RANGE:
 488                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 489                 lue->attr.loglevel = ev->loglevel;
 490                 break;
 491         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 492                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 493                 lue->attr.loglevel = ev->loglevel;
 494                 break;
 495         default:
 496                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 497                 goto error_free_event;
 498         }
 499
 500         /* Same layout. */
 501         lue->filter_expression = filter_expression;
 502         lue->filter = filter;
 503         lue->exclusion = exclusion;
 504
 505         /* Init node */
 506         lttng_ht_node_init_str(&lue->node, lue->attr.name);
 507
 508         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 509                 lue->attr.name, lue->attr.loglevel_type,
 510                 lue->attr.loglevel);
 511
 512         return lue;
 513
 514 error_free_event:
 515         free(lue);
 516 error:
 517         free(filter_expression);
 518         free(filter);
 519         free(exclusion);
 520         return NULL;
 521 }
 522
 523 static
 524 int trace_ust_context_type_event_to_ust(
 525                 enum lttng_event_context_type type)
 526 {
 527         int utype;
 528
 529         switch (type) {
 530         case LTTNG_EVENT_CONTEXT_VTID:
 531                 utype = LTTNG_UST_CONTEXT_VTID;
 532                 break;
 533         case LTTNG_EVENT_CONTEXT_VPID:
 534                 utype = LTTNG_UST_CONTEXT_VPID;
 535                 break;
 536         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 537                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 538                 break;
 539         case LTTNG_EVENT_CONTEXT_PROCNAME:
 540                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 541                 break;
 542         case LTTNG_EVENT_CONTEXT_IP:
 543                 utype = LTTNG_UST_CONTEXT_IP;
 544                 break;
 545         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 546                 if (!ustctl_has_perf_counters()) {
 547                         utype = -1;
 548                         WARN("Perf counters not implemented in UST");
 549                 } else {
 550                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 551                 }
 552                 break;
 553         case LTTNG_EVENT_CONTEXT_APP_CONTEXT:
 554                 utype = LTTNG_UST_CONTEXT_APP_CONTEXT;
 555                 break;
 556         default:
 557                 utype = -1;
 558                 break;
 559         }
 560         return utype;
 561 }
 562
 563 /*
 564  * Return 1 if contexts match, 0 otherwise.
 565  */
 566 int trace_ust_match_context(struct ltt_ust_context *uctx,
 567                 struct lttng_event_context *ctx)
 568 {
 569         int utype;
 570
 571         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 572         if (utype < 0) {
 573                 return 0;
 574         }
 575         if (uctx->ctx.ctx != utype) {
 576                 return 0;
 577         }
 578         switch (utype) {
 579         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 580                 if (uctx->ctx.u.perf_counter.type
 581                                 != ctx->u.perf_counter.type) {
 582                         return 0;
 583                 }
 584                 if (uctx->ctx.u.perf_counter.config
 585                                 != ctx->u.perf_counter.config) {
 586                         return 0;
 587                 }
 588                 if (strncmp(uctx->ctx.u.perf_counter.name,
 589                                 ctx->u.perf_counter.name,
 590                                 LTTNG_UST_SYM_NAME_LEN)) {
 591                         return 0;
 592                 }
 593                 break;
 594         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 595                 assert(uctx->ctx.u.app_ctx.provider_name);
 596                 assert(uctx->ctx.u.app_ctx.ctx_name);
 597                 if (strcmp(uctx->ctx.u.app_ctx.provider_name,
 598                                 ctx->u.app_ctx.provider_name) ||
 599                                 strcmp(uctx->ctx.u.app_ctx.ctx_name,
 600                                 ctx->u.app_ctx.ctx_name)) {
 601                         return 0;
 602                 }
 603         default:
 604                 break;
 605
 606         }
 607         return 1;
 608 }
 609
 610 /*
 611  * Allocate and initialize an UST context.
 612  *
 613  * Return pointer to structure or NULL.
 614  */
 615 struct ltt_ust_context *trace_ust_create_context(
 616                 struct lttng_event_context *ctx)
 617 {
 618         struct ltt_ust_context *uctx = NULL;
 619         int utype;
 620
 621         assert(ctx);
 622
 623         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 624         if (utype < 0) {
 625                 ERR("Invalid UST context");
 626                 goto end;
 627         }
 628
 629         uctx = zmalloc(sizeof(struct ltt_ust_context));
 630         if (!uctx) {
 631                 PERROR("zmalloc ltt_ust_context");
 632                 goto end;
 633         }
 634
 635         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 636         switch (utype) {
 637         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 638                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 639                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 640                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 641                                 LTTNG_UST_SYM_NAME_LEN);
 642                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 643                 break;
 644         case LTTNG_UST_CONTEXT_APP_CONTEXT:
 645         {
 646                 char *provider_name = NULL, *ctx_name = NULL;
 647
 648                 provider_name = strdup(ctx->u.app_ctx.provider_name);
 649                 if (!provider_name) {
 650                         goto error;
 651                 }
 652                 uctx->ctx.u.app_ctx.provider_name = provider_name;
 653
 654                 ctx_name = strdup(ctx->u.app_ctx.ctx_name);
 655                 if (!ctx_name) {
 656                         goto error;
 657                 }
 658                 uctx->ctx.u.app_ctx.ctx_name = ctx_name;
 659                 break;
 660         }
 661         default:
 662                 break;
 663         }
 664         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 665 end:
 666         return uctx;
 667 error:
 668         trace_ust_destroy_context(uctx);
 669         return NULL;
 670 }
 671
 672 static
 673 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 674 {
 675         struct ust_pid_tracker_node *tracker_node =
 676                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 677         free(tracker_node);
 678 }
 679
 680 static
 681 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 682 {
 683
 684         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 685 }
 686
 687 static
 688 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 689 {
 690         int ret = 0;
 691
 692         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 693         if (!pid_tracker->ht) {
 694                 ret = -1;
 695                 goto end;
 696         }
 697
 698 end:
 699         return ret;
 700 }
 701
 702 /*
 703  * Teardown pid tracker content, but don't free pid_tracker object.
 704  */
 705 static
 706 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 707 {
 708         struct ust_pid_tracker_node *tracker_node;
 709         struct lttng_ht_iter iter;
 710
 711         if (!pid_tracker->ht) {
 712                 return;
 713         }
 714         rcu_read_lock();
 715         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 716                         &iter.iter, tracker_node, node.node) {
 717                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 718
 719                 assert(!ret);
 720                 destroy_pid_tracker_node(tracker_node);
 721         }
 722         rcu_read_unlock();
 723         ht_cleanup_push(pid_tracker->ht);
 724         pid_tracker->ht = NULL;
 725 }
 726
 727 static
 728 struct ust_pid_tracker_node *pid_tracker_lookup(
 729                 struct ust_pid_tracker *pid_tracker, int pid,
 730                 struct lttng_ht_iter *iter)
 731 {
 732         unsigned long _pid = (unsigned long) pid;
 733         struct lttng_ht_node_ulong *node;
 734
 735         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 736         node = lttng_ht_iter_get_node_ulong(iter);
 737         if (node) {
 738                 return caa_container_of(node, struct ust_pid_tracker_node,
 739                         node);
 740         } else {
 741                 return NULL;
 742         }
 743 }
 744
 745 static
 746 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 747 {
 748         int retval = LTTNG_OK;
 749         struct ust_pid_tracker_node *tracker_node;
 750         struct lttng_ht_iter iter;
 751
 752         if (pid < 0) {
 753                 retval = LTTNG_ERR_INVALID;
 754                 goto end;
 755         }
 756         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 757         if (tracker_node) {
 758                 /* Already exists. */
 759                 retval = LTTNG_ERR_PID_TRACKED;
 760                 goto end;
 761         }
 762         tracker_node = zmalloc(sizeof(*tracker_node));
 763         if (!tracker_node) {
 764                 retval = LTTNG_ERR_NOMEM;
 765                 goto end;
 766         }
 767         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 768         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 769 end:
 770         return retval;
 771 }
 772
 773 static
 774 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 775 {
 776         int retval = LTTNG_OK, ret;
 777         struct ust_pid_tracker_node *tracker_node;
 778         struct lttng_ht_iter iter;
 779
 780         if (pid < 0) {
 781                 retval = LTTNG_ERR_INVALID;
 782                 goto end;
 783         }
 784         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 785         if (!tracker_node) {
 786                 /* Not found */
 787                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 788                 goto end;
 789         }
 790         ret = lttng_ht_del(pid_tracker->ht, &iter);
 791         assert(!ret);
 792
 793         destroy_pid_tracker_node(tracker_node);
 794 end:
 795         return retval;
 796 }
 797
 798 /*
 799  * The session lock is held when calling this function.
 800  */
 801 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 802 {
 803         struct lttng_ht_iter iter;
 804
 805         if (!session->pid_tracker.ht) {
 806                 return 1;
 807         }
 808         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 809                 return 1;
 810         }
 811         return 0;
 812 }
 813
 814 /*
 815  * Called with the session lock held.
 816  */
 817 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 818 {
 819         int retval = LTTNG_OK;
 820
 821         if (pid == -1) {
 822                 /* Track all pids: destroy tracker if exists. */
 823                 if (session->pid_tracker.ht) {
 824                         fini_pid_tracker(&session->pid_tracker);
 825                         /* Ensure all apps have session. */
 826                         ust_app_global_update_all(session);
 827                 }
 828         } else {
 829                 int ret;
 830
 831                 if (!session->pid_tracker.ht) {
 832                         /* Create tracker. */
 833                         if (init_pid_tracker(&session->pid_tracker)) {
 834                                 ERR("Error initializing PID tracker");
 835                                 retval = LTTNG_ERR_NOMEM;
 836                                 goto end;
 837                         }
 838                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 839                         if (ret != LTTNG_OK) {
 840                                 retval = ret;
 841                                 fini_pid_tracker(&session->pid_tracker);
 842                                 goto end;
 843                         }
 844                         /* Remove all apps from session except pid. */
 845                         ust_app_global_update_all(session);
 846                 } else {
 847                         struct ust_app *app;
 848
 849                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 850                         if (ret != LTTNG_OK) {
 851                                 retval = ret;
 852                                 goto end;
 853                         }
 854                         /* Add session to application */
 855                         app = ust_app_find_by_pid(pid);
 856                         if (app) {
 857                                 ust_app_global_update(session, app);
 858                         }
 859                 }
 860         }
 861 end:
 862         return retval;
 863 }
 864
 865 /*
 866  * Called with the session lock held.
 867  */
 868 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 869 {
 870         int retval = LTTNG_OK;
 871
 872         if (pid == -1) {
 873                 /* Create empty tracker, replace old tracker. */
 874                 struct ust_pid_tracker tmp_tracker;
 875
 876                 tmp_tracker = session->pid_tracker;
 877                 if (init_pid_tracker(&session->pid_tracker)) {
 878                         ERR("Error initializing PID tracker");
 879                         retval = LTTNG_ERR_NOMEM;
 880                         /* Rollback operation. */
 881                         session->pid_tracker = tmp_tracker;
 882                         goto end;
 883                 }
 884                 fini_pid_tracker(&tmp_tracker);
 885
 886                 /* Remove session from all applications */
 887                 ust_app_global_update_all(session);
 888         } else {
 889                 int ret;
 890                 struct ust_app *app;
 891
 892                 if (!session->pid_tracker.ht) {
 893                         /* No PID being tracked. */
 894                         retval = LTTNG_ERR_PID_NOT_TRACKED;
 895                         goto end;
 896                 }
 897                 /* Remove PID from tracker */
 898                 ret = pid_tracker_del_pid(&session->pid_tracker, pid);
 899                 if (ret != LTTNG_OK) {
 900                         retval = ret;
 901                         goto end;
 902                 }
 903                 /* Remove session from application. */
 904                 app = ust_app_find_by_pid(pid);
 905                 if (app) {
 906                         ust_app_global_update(session, app);
 907                 }
 908         }
 909 end:
 910         return retval;
 911 }
 912
 913 /*
 914  * Called with session lock held.
 915  */
 916 ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
 917                 int32_t **_pids)
 918 {
 919         struct ust_pid_tracker_node *tracker_node;
 920         struct lttng_ht_iter iter;
 921         unsigned long count, i = 0;
 922         long approx[2];
 923         int32_t *pids;
 924         int ret = 0;
 925
 926         if (!session->pid_tracker.ht) {
 927                 /* Tracker disabled. Set first entry to -1. */
 928                 pids = zmalloc(sizeof(*pids));
 929                 if (!pids) {
 930                         ret = -1;
 931                         goto end;
 932                 }
 933                 pids[0] = -1;
 934                 *_pids = pids;
 935                 return 1;
 936         }
 937
 938         rcu_read_lock();
 939         cds_lfht_count_nodes(session->pid_tracker.ht->ht,
 940                 &approx[0], &count, &approx[1]);
 941         pids = zmalloc(sizeof(*pids) * count);
 942         if (!pids) {
 943                 ret = -1;
 944                 goto end;
 945         }
 946         cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
 947                         &iter.iter, tracker_node, node.node) {
 948                 pids[i++] = tracker_node->node.key;
 949         }
 950         *_pids = pids;
 951         ret = count;
 952 end:
 953         rcu_read_unlock();
 954         return ret;
 955 }
 956
 957 /*
 958  * RCU safe free context structure.
 959  */
 960 static void destroy_context_rcu(struct rcu_head *head)
 961 {
 962         struct lttng_ht_node_ulong *node =
 963                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 964         struct ltt_ust_context *ctx =
 965                 caa_container_of(node, struct ltt_ust_context, node);
 966
 967         trace_ust_destroy_context(ctx);
 968 }
 969
 970 /*
 971  * Cleanup UST context hash table.
 972  */
 973 static void destroy_contexts(struct lttng_ht *ht)
 974 {
 975         int ret;
 976         struct lttng_ht_node_ulong *node;
 977         struct lttng_ht_iter iter;
 978         struct ltt_ust_context *ctx;
 979
 980         assert(ht);
 981
 982         rcu_read_lock();
 983         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
 984                 /* Remove from ordered list. */
 985                 ctx = caa_container_of(node, struct ltt_ust_context, node);
 986                 cds_list_del(&ctx->list);
 987                 /* Remove from channel's hash table. */
 988                 ret = lttng_ht_del(ht, &iter);
 989                 if (!ret) {
 990                         call_rcu(&node->head, destroy_context_rcu);
 991                 }
 992         }
 993         rcu_read_unlock();
 994
 995         ht_cleanup_push(ht);
 996 }
 997
 998 /*
 999  * Cleanup ust event structure.
1000  */
1001 void trace_ust_destroy_event(struct ltt_ust_event *event)
1002 {
1003         assert(event);
1004
1005         DBG2("Trace destroy UST event %s", event->attr.name);
1006         free(event->filter_expression);
1007         free(event->filter);
1008         free(event->exclusion);
1009         free(event);
1010 }
1011
1012 /*
1013  * Cleanup ust context structure.
1014  */
1015 void trace_ust_destroy_context(struct ltt_ust_context *ctx)
1016 {
1017         assert(ctx);
1018
1019         if (ctx->ctx.ctx == LTTNG_UST_CONTEXT_APP_CONTEXT) {
1020                 free(ctx->ctx.u.app_ctx.provider_name);
1021                 free(ctx->ctx.u.app_ctx.ctx_name);
1022         }
1023         free(ctx);
1024 }
1025
1026 /*
1027  * URCU intermediate call to complete destroy event.
1028  */
1029 static void destroy_event_rcu(struct rcu_head *head)
1030 {
1031         struct lttng_ht_node_str *node =
1032                 caa_container_of(head, struct lttng_ht_node_str, head);
1033         struct ltt_ust_event *event =
1034                 caa_container_of(node, struct ltt_ust_event, node);
1035
1036         trace_ust_destroy_event(event);
1037 }
1038
1039 /*
1040  * Cleanup UST events hashtable.
1041  */
1042 static void destroy_events(struct lttng_ht *events)
1043 {
1044         int ret;
1045         struct lttng_ht_node_str *node;
1046         struct lttng_ht_iter iter;
1047
1048         assert(events);
1049
1050         rcu_read_lock();
1051         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
1052                 ret = lttng_ht_del(events, &iter);
1053                 assert(!ret);
1054                 call_rcu(&node->head, destroy_event_rcu);
1055         }
1056         rcu_read_unlock();
1057
1058         ht_cleanup_push(events);
1059 }
1060
1061 /*
1062  * Cleanup ust channel structure.
1063  *
1064  * Should _NOT_ be called with RCU read lock held.
1065  */
1066 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1067 {
1068         assert(channel);
1069
1070         DBG2("Trace destroy UST channel %s", channel->name);
1071
1072         free(channel);
1073 }
1074
1075 /*
1076  * URCU intermediate call to complete destroy channel.
1077  */
1078 static void destroy_channel_rcu(struct rcu_head *head)
1079 {
1080         struct lttng_ht_node_str *node =
1081                 caa_container_of(head, struct lttng_ht_node_str, head);
1082         struct ltt_ust_channel *channel =
1083                 caa_container_of(node, struct ltt_ust_channel, node);
1084
1085         _trace_ust_destroy_channel(channel);
1086 }
1087
1088 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
1089 {
1090         /* Destroying all events of the channel */
1091         destroy_events(channel->events);
1092         /* Destroying all context of the channel */
1093         destroy_contexts(channel->ctx);
1094
1095         call_rcu(&channel->node.head, destroy_channel_rcu);
1096 }
1097
1098 /*
1099  * Remove an UST channel from a channel HT.
1100  */
1101 void trace_ust_delete_channel(struct lttng_ht *ht,
1102                 struct ltt_ust_channel *channel)
1103 {
1104         int ret;
1105         struct lttng_ht_iter iter;
1106
1107         assert(ht);
1108         assert(channel);
1109
1110         iter.iter.node = &channel->node.node;
1111         ret = lttng_ht_del(ht, &iter);
1112         assert(!ret);
1113 }
1114
1115 /*
1116  * Iterate over a hash table containing channels and cleanup safely.
1117  */
1118 static void destroy_channels(struct lttng_ht *channels)
1119 {
1120         struct lttng_ht_node_str *node;
1121         struct lttng_ht_iter iter;
1122
1123         assert(channels);
1124
1125         rcu_read_lock();
1126         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1127                 struct ltt_ust_channel *chan =
1128                         caa_container_of(node, struct ltt_ust_channel, node);
1129
1130                 trace_ust_delete_channel(channels, chan);
1131                 trace_ust_destroy_channel(chan);
1132         }
1133         rcu_read_unlock();
1134
1135         ht_cleanup_push(channels);
1136 }
1137
1138 /*
1139  * Cleanup UST global domain.
1140  */
1141 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1142 {
1143         assert(dom);
1144
1145         destroy_channels(dom->channels);
1146 }
1147
1148 /*
1149  * Cleanup ust session structure
1150  *
1151  * Should *NOT* be called with RCU read-side lock held.
1152  */
1153 void trace_ust_destroy_session(struct ltt_ust_session *session)
1154 {
1155         struct agent *agt;
1156         struct buffer_reg_uid *reg, *sreg;
1157         struct lttng_ht_iter iter;
1158
1159         assert(session);
1160
1161         DBG2("Trace UST destroy session %" PRIu64, session->id);
1162
1163         /* Cleaning up UST domain */
1164         destroy_domain_global(&session->domain_global);
1165
1166         rcu_read_lock();
1167         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1168                 int ret = lttng_ht_del(session->agents, &iter);
1169
1170                 assert(!ret);
1171                 agent_destroy(agt);
1172         }
1173         rcu_read_unlock();
1174
1175         ht_cleanup_push(session->agents);
1176
1177         /* Cleanup UID buffer registry object(s). */
1178         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1179                         lnode) {
1180                 cds_list_del(&reg->lnode);
1181                 buffer_reg_uid_remove(reg);
1182                 buffer_reg_uid_destroy(reg, session->consumer);
1183         }
1184
1185         consumer_output_put(session->consumer);
1186
1187         fini_pid_tracker(&session->pid_tracker);
1188
1189         free(session);
1190 }