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

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License, version 2 only,
   6  * as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #define _LGPL_SOURCE
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <inttypes.h>
  25
  26 #include <common/common.h>
  27 #include <common/defaults.h>
  28
  29 #include "buffer-registry.h"
  30 #include "trace-ust.h"
  31 #include "utils.h"
  32 #include "ust-app.h"
  33 #include "agent.h"
  34
  35 /*
  36  * Match function for the events hash table lookup.
  37  *
  38  * Matches by name only. Used by the disable command.
  39  */
  40 int trace_ust_ht_match_event_by_name(struct cds_lfht_node *node,
  41                 const void *_key)
  42 {
  43         struct ltt_ust_event *event;
  44         const char *name;
  45
  46         assert(node);
  47         assert(_key);
  48
  49         event = caa_container_of(node, struct ltt_ust_event, node.node);
  50         name = _key;
  51
  52         /* Event name */
  53         if (strncmp(event->attr.name, name, sizeof(event->attr.name)) != 0) {
  54                 goto no_match;
  55         }
  56
  57         /* Match */
  58         return 1;
  59
  60 no_match:
  61         return 0;
  62 }
  63
  64 /*
  65  * Match function for the hash table lookup.
  66  *
  67  * It matches an ust event based on three attributes which are the event name,
  68  * the filter bytecode and the loglevel.
  69  */
  70 int trace_ust_ht_match_event(struct cds_lfht_node *node, const void *_key)
  71 {
  72         struct ltt_ust_event *event;
  73         const struct ltt_ust_ht_key *key;
  74
  75         assert(node);
  76         assert(_key);
  77
  78         event = caa_container_of(node, struct ltt_ust_event, node.node);
  79         key = _key;
  80
  81         /* Match the 4 elements of the key: name, filter, loglevel, exclusions. */
  82
  83         /* Event name */
  84         if (strncmp(event->attr.name, key->name, sizeof(event->attr.name)) != 0) {
  85                 goto no_match;
  86         }
  87
  88         /* Event loglevel. */
  89         if (event->attr.loglevel != key->loglevel) {
  90                 if (event->attr.loglevel_type == LTTNG_UST_LOGLEVEL_ALL
  91                                 && key->loglevel == 0 && event->attr.loglevel == -1) {
  92                         /*
  93                          * Match is accepted. This is because on event creation, the
  94                          * loglevel is set to -1 if the event loglevel type is ALL so 0 and
  95                          * -1 are accepted for this loglevel type since 0 is the one set by
  96                          * the API when receiving an enable event.
  97                          */
  98                 } else {
  99                         goto no_match;
 100                 }
 101         }
 102
 103         /* Only one of the filters is NULL, fail. */
 104         if ((key->filter && !event->filter) || (!key->filter && event->filter)) {
 105                 goto no_match;
 106         }
 107
 108         if (key->filter && event->filter) {
 109                 /* Both filters exists, check length followed by the bytecode. */
 110                 if (event->filter->len != key->filter->len ||
 111                                 memcmp(event->filter->data, key->filter->data,
 112                                         event->filter->len) != 0) {
 113                         goto no_match;
 114                 }
 115         }
 116
 117         /* If only one of the exclusions is NULL, fail. */
 118         if ((key->exclusion && !event->exclusion) || (!key->exclusion && event->exclusion)) {
 119                 goto no_match;
 120         }
 121
 122         if (key->exclusion && event->exclusion) {
 123                 /* Both exclusions exist; check count followed by names. */
 124                 if (event->exclusion->count != key->exclusion->count ||
 125                                 memcmp(event->exclusion->names, key->exclusion->names,
 126                                         event->exclusion->count * LTTNG_SYMBOL_NAME_LEN) != 0) {
 127                         goto no_match;
 128                 }
 129         }
 130         /* Match. */
 131         return 1;
 132
 133 no_match:
 134         return 0;
 135 }
 136
 137 /*
 138  * Find the channel in the hashtable and return channel pointer. RCU read side
 139  * lock MUST be acquired before calling this.
 140  */
 141 struct ltt_ust_channel *trace_ust_find_channel_by_name(struct lttng_ht *ht,
 142                 char *name)
 143 {
 144         struct lttng_ht_node_str *node;
 145         struct lttng_ht_iter iter;
 146
 147         /*
 148          * If we receive an empty string for channel name, it means the
 149          * default channel name is requested.
 150          */
 151         if (name[0] == '\0')
 152                 name = DEFAULT_CHANNEL_NAME;
 153
 154         lttng_ht_lookup(ht, (void *)name, &iter);
 155         node = lttng_ht_iter_get_node_str(&iter);
 156         if (node == NULL) {
 157                 goto error;
 158         }
 159
 160         DBG2("Trace UST channel %s found by name", name);
 161
 162         return caa_container_of(node, struct ltt_ust_channel, node);
 163
 164 error:
 165         DBG2("Trace UST channel %s not found by name", name);
 166         return NULL;
 167 }
 168
 169 /*
 170  * Find the event in the hashtable and return event pointer. RCU read side lock
 171  * MUST be acquired before calling this.
 172  */
 173 struct ltt_ust_event *trace_ust_find_event(struct lttng_ht *ht,
 174                 char *name, struct lttng_filter_bytecode *filter, int loglevel,
 175                 struct lttng_event_exclusion *exclusion)
 176 {
 177         struct lttng_ht_node_str *node;
 178         struct lttng_ht_iter iter;
 179         struct ltt_ust_ht_key key;
 180
 181         assert(name);
 182         assert(ht);
 183
 184         key.name = name;
 185         key.filter = filter;
 186         key.loglevel = loglevel;
 187         key.exclusion = exclusion;
 188
 189         cds_lfht_lookup(ht->ht, ht->hash_fct((void *) name, lttng_ht_seed),
 190                         trace_ust_ht_match_event, &key, &iter.iter);
 191         node = lttng_ht_iter_get_node_str(&iter);
 192         if (node == NULL) {
 193                 goto error;
 194         }
 195
 196         DBG2("Trace UST event %s found", key.name);
 197
 198         return caa_container_of(node, struct ltt_ust_event, node);
 199
 200 error:
 201         DBG2("Trace UST event %s NOT found", key.name);
 202         return NULL;
 203 }
 204
 205 /*
 206  * Lookup an agent in the session agents hash table by domain type and return
 207  * the object if found else NULL.
 208  *
 209  * RCU read side lock must be acquired before calling and only released
 210  * once the agent is no longer in scope or being used.
 211  */
 212 struct agent *trace_ust_find_agent(struct ltt_ust_session *session,
 213                 enum lttng_domain_type domain_type)
 214 {
 215         struct agent *agt = NULL;
 216         struct lttng_ht_node_u64 *node;
 217         struct lttng_ht_iter iter;
 218         uint64_t key;
 219
 220         assert(session);
 221
 222         DBG3("Trace ust agent lookup for domain %d", domain_type);
 223
 224         key = domain_type;
 225
 226         lttng_ht_lookup(session->agents, &key, &iter);
 227         node = lttng_ht_iter_get_node_u64(&iter);
 228         if (!node) {
 229                 goto end;
 230         }
 231         agt = caa_container_of(node, struct agent, node);
 232
 233 end:
 234         return agt;
 235 }
 236
 237 /*
 238  * Allocate and initialize a ust session data structure.
 239  *
 240  * Return pointer to structure or NULL.
 241  */
 242 struct ltt_ust_session *trace_ust_create_session(uint64_t session_id)
 243 {
 244         struct ltt_ust_session *lus;
 245
 246         /* Allocate a new ltt ust session */
 247         lus = zmalloc(sizeof(struct ltt_ust_session));
 248         if (lus == NULL) {
 249                 PERROR("create ust session zmalloc");
 250                 goto error;
 251         }
 252
 253         /* Init data structure */
 254         lus->id = session_id;
 255         lus->active = 0;
 256
 257         /* Set default metadata channel attribute. */
 258         lus->metadata_attr.overwrite = DEFAULT_CHANNEL_OVERWRITE;
 259         lus->metadata_attr.subbuf_size = default_get_metadata_subbuf_size();
 260         lus->metadata_attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM;
 261         lus->metadata_attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER;
 262         lus->metadata_attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER;
 263         lus->metadata_attr.output = LTTNG_UST_MMAP;
 264
 265         /*
 266          * Default buffer type. This can be changed through an enable channel
 267          * requesting a different type. Note that this can only be changed once
 268          * during the session lifetime which is at the first enable channel and
 269          * only before start. The flag buffer_type_changed indicates the status.
 270          */
 271         lus->buffer_type = LTTNG_BUFFER_PER_UID;
 272         /* Once set to 1, the buffer_type is immutable for the session. */
 273         lus->buffer_type_changed = 0;
 274         /* Init it in case it get used after allocation. */
 275         CDS_INIT_LIST_HEAD(&lus->buffer_reg_uid_list);
 276
 277         /* Alloc UST global domain channels' HT */
 278         lus->domain_global.channels = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 279         /* Alloc agent hash table. */
 280         lus->agents = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 281
 282         lus->consumer = consumer_create_output(CONSUMER_DST_LOCAL);
 283         if (lus->consumer == NULL) {
 284                 goto error_consumer;
 285         }
 286
 287         /*
 288          * The tmp_consumer stays NULL until a set_consumer_uri command is
 289          * executed. At this point, the consumer should be nullify until an
 290          * enable_consumer command. This assignment is symbolic since we've zmalloc
 291          * the struct.
 292          */
 293         lus->tmp_consumer = NULL;
 294
 295         DBG2("UST trace session create successful");
 296
 297         return lus;
 298
 299 error_consumer:
 300         ht_cleanup_push(lus->domain_global.channels);
 301         ht_cleanup_push(lus->agents);
 302         free(lus);
 303 error:
 304         return NULL;
 305 }
 306
 307 /*
 308  * Allocate and initialize a ust channel data structure.
 309  *
 310  * Return pointer to structure or NULL.
 311  */
 312 struct ltt_ust_channel *trace_ust_create_channel(struct lttng_channel *chan,
 313                 enum lttng_domain_type domain)
 314 {
 315         struct ltt_ust_channel *luc;
 316
 317         assert(chan);
 318
 319         luc = zmalloc(sizeof(struct ltt_ust_channel));
 320         if (luc == NULL) {
 321                 PERROR("ltt_ust_channel zmalloc");
 322                 goto error;
 323         }
 324
 325         luc->domain = domain;
 326
 327         /* Copy UST channel attributes */
 328         luc->attr.overwrite = chan->attr.overwrite;
 329         luc->attr.subbuf_size = chan->attr.subbuf_size;
 330         luc->attr.num_subbuf = chan->attr.num_subbuf;
 331         luc->attr.switch_timer_interval = chan->attr.switch_timer_interval;
 332         luc->attr.read_timer_interval = chan->attr.read_timer_interval;
 333         luc->attr.output = (enum lttng_ust_output) chan->attr.output;
 334
 335         /* Translate to UST output enum */
 336         switch (luc->attr.output) {
 337         default:
 338                 luc->attr.output = LTTNG_UST_MMAP;
 339                 break;
 340         }
 341
 342         /*
 343          * If we receive an empty string for channel name, it means the
 344          * default channel name is requested.
 345          */
 346         if (chan->name[0] == '\0') {
 347                 strncpy(luc->name, DEFAULT_CHANNEL_NAME, sizeof(luc->name));
 348         } else {
 349                 /* Copy channel name */
 350                 strncpy(luc->name, chan->name, sizeof(luc->name));
 351         }
 352         luc->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 353
 354         /* Init node */
 355         lttng_ht_node_init_str(&luc->node, luc->name);
 356         CDS_INIT_LIST_HEAD(&luc->ctx_list);
 357
 358         /* Alloc hash tables */
 359         luc->events = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 360         luc->ctx = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 361
 362         /* On-disk circular buffer parameters */
 363         luc->tracefile_size = chan->attr.tracefile_size;
 364         luc->tracefile_count = chan->attr.tracefile_count;
 365
 366         DBG2("Trace UST channel %s created", luc->name);
 367
 368 error:
 369         return luc;
 370 }
 371
 372 /*
 373  * Allocate and initialize a ust event. Set name and event type.
 374  * We own filter_expression, filter, and exclusion.
 375  *
 376  * Return pointer to structure or NULL.
 377  */
 378 struct ltt_ust_event *trace_ust_create_event(struct lttng_event *ev,
 379                 char *filter_expression,
 380                 struct lttng_filter_bytecode *filter,
 381                 struct lttng_event_exclusion *exclusion,
 382                 bool internal_event)
 383 {
 384         struct ltt_ust_event *lue;
 385
 386         assert(ev);
 387
 388         lue = zmalloc(sizeof(struct ltt_ust_event));
 389         if (lue == NULL) {
 390                 PERROR("ust event zmalloc");
 391                 goto error;
 392         }
 393
 394         lue->internal = internal_event;
 395
 396         switch (ev->type) {
 397         case LTTNG_EVENT_PROBE:
 398                 lue->attr.instrumentation = LTTNG_UST_PROBE;
 399                 break;
 400         case LTTNG_EVENT_FUNCTION:
 401                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 402                 break;
 403         case LTTNG_EVENT_FUNCTION_ENTRY:
 404                 lue->attr.instrumentation = LTTNG_UST_FUNCTION;
 405                 break;
 406         case LTTNG_EVENT_TRACEPOINT:
 407                 lue->attr.instrumentation = LTTNG_UST_TRACEPOINT;
 408                 break;
 409         default:
 410                 ERR("Unknown ust instrumentation type (%d)", ev->type);
 411                 goto error_free_event;
 412         }
 413
 414         /* Copy event name */
 415         strncpy(lue->attr.name, ev->name, LTTNG_UST_SYM_NAME_LEN);
 416         lue->attr.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 417
 418         switch (ev->loglevel_type) {
 419         case LTTNG_EVENT_LOGLEVEL_ALL:
 420                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_ALL;
 421                 lue->attr.loglevel = -1;        /* Force to -1 */
 422                 break;
 423         case LTTNG_EVENT_LOGLEVEL_RANGE:
 424                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_RANGE;
 425                 lue->attr.loglevel = ev->loglevel;
 426                 break;
 427         case LTTNG_EVENT_LOGLEVEL_SINGLE:
 428                 lue->attr.loglevel_type = LTTNG_UST_LOGLEVEL_SINGLE;
 429                 lue->attr.loglevel = ev->loglevel;
 430                 break;
 431         default:
 432                 ERR("Unknown ust loglevel type (%d)", ev->loglevel_type);
 433                 goto error_free_event;
 434         }
 435
 436         /* Same layout. */
 437         lue->filter_expression = filter_expression;
 438         lue->filter = filter;
 439         lue->exclusion = exclusion;
 440
 441         /* Init node */
 442         lttng_ht_node_init_str(&lue->node, lue->attr.name);
 443
 444         DBG2("Trace UST event %s, loglevel (%d,%d) created",
 445                 lue->attr.name, lue->attr.loglevel_type,
 446                 lue->attr.loglevel);
 447
 448         return lue;
 449
 450 error_free_event:
 451         free(lue);
 452 error:
 453         free(filter_expression);
 454         free(filter);
 455         free(exclusion);
 456         return NULL;
 457 }
 458
 459 static
 460 int trace_ust_context_type_event_to_ust(enum lttng_event_context_type type)
 461 {
 462         int utype;
 463
 464         switch (type) {
 465         case LTTNG_EVENT_CONTEXT_VTID:
 466                 utype = LTTNG_UST_CONTEXT_VTID;
 467                 break;
 468         case LTTNG_EVENT_CONTEXT_VPID:
 469                 utype = LTTNG_UST_CONTEXT_VPID;
 470                 break;
 471         case LTTNG_EVENT_CONTEXT_PTHREAD_ID:
 472                 utype = LTTNG_UST_CONTEXT_PTHREAD_ID;
 473                 break;
 474         case LTTNG_EVENT_CONTEXT_PROCNAME:
 475                 utype = LTTNG_UST_CONTEXT_PROCNAME;
 476                 break;
 477         case LTTNG_EVENT_CONTEXT_IP:
 478                 utype = LTTNG_UST_CONTEXT_IP;
 479                 break;
 480         case LTTNG_EVENT_CONTEXT_PERF_THREAD_COUNTER:
 481                 if (!ustctl_has_perf_counters()) {
 482                         utype = -1;
 483                         WARN("Perf counters not implemented in UST");
 484                 } else {
 485                         utype = LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER;
 486                 }
 487                 break;
 488         default:
 489                 ERR("Invalid UST context");
 490                 utype = -1;
 491                 break;
 492         }
 493         return utype;
 494 }
 495
 496 /*
 497  * Return 1 if contexts match, 0 otherwise.
 498  */
 499 int trace_ust_match_context(struct ltt_ust_context *uctx,
 500                 struct lttng_event_context *ctx)
 501 {
 502         int utype;
 503
 504         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 505         if (utype < 0) {
 506                 return 0;
 507         }
 508         if (uctx->ctx.ctx != utype) {
 509                 return 0;
 510         }
 511         switch (utype) {
 512         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 513                 if (uctx->ctx.u.perf_counter.type
 514                                 != ctx->u.perf_counter.type) {
 515                         return 0;
 516                 }
 517                 if (uctx->ctx.u.perf_counter.config
 518                                 != ctx->u.perf_counter.config) {
 519                         return 0;
 520                 }
 521                 if (strncmp(uctx->ctx.u.perf_counter.name,
 522                                 ctx->u.perf_counter.name,
 523                                 LTTNG_UST_SYM_NAME_LEN)) {
 524                         return 0;
 525                 }
 526                 break;
 527         default:
 528                 break;
 529
 530         }
 531         return 1;
 532 }
 533
 534 /*
 535  * Allocate and initialize an UST context.
 536  *
 537  * Return pointer to structure or NULL.
 538  */
 539 struct ltt_ust_context *trace_ust_create_context(
 540                 struct lttng_event_context *ctx)
 541 {
 542         struct ltt_ust_context *uctx;
 543         int utype;
 544
 545         assert(ctx);
 546
 547         utype = trace_ust_context_type_event_to_ust(ctx->ctx);
 548         if (utype < 0) {
 549                 return NULL;
 550         }
 551
 552         uctx = zmalloc(sizeof(struct ltt_ust_context));
 553         if (uctx == NULL) {
 554                 PERROR("zmalloc ltt_ust_context");
 555                 goto error;
 556         }
 557
 558         uctx->ctx.ctx = (enum lttng_ust_context_type) utype;
 559         switch (utype) {
 560         case LTTNG_UST_CONTEXT_PERF_THREAD_COUNTER:
 561                 uctx->ctx.u.perf_counter.type = ctx->u.perf_counter.type;
 562                 uctx->ctx.u.perf_counter.config = ctx->u.perf_counter.config;
 563                 strncpy(uctx->ctx.u.perf_counter.name, ctx->u.perf_counter.name,
 564                                 LTTNG_UST_SYM_NAME_LEN);
 565                 uctx->ctx.u.perf_counter.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 566                 break;
 567         default:
 568                 break;
 569         }
 570         lttng_ht_node_init_ulong(&uctx->node, (unsigned long) uctx->ctx.ctx);
 571
 572         return uctx;
 573
 574 error:
 575         return NULL;
 576 }
 577
 578 static
 579 void destroy_pid_tracker_node_rcu(struct rcu_head *head)
 580 {
 581         struct ust_pid_tracker_node *tracker_node =
 582                 caa_container_of(head, struct ust_pid_tracker_node, node.head);
 583         free(tracker_node);
 584 }
 585
 586 static
 587 void destroy_pid_tracker_node(struct ust_pid_tracker_node *tracker_node)
 588 {
 589
 590         call_rcu(&tracker_node->node.head, destroy_pid_tracker_node_rcu);
 591 }
 592
 593 static
 594 int init_pid_tracker(struct ust_pid_tracker *pid_tracker)
 595 {
 596         int ret = 0;
 597
 598         pid_tracker->ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
 599         if (!pid_tracker->ht) {
 600                 ret = -1;
 601                 goto end;
 602         }
 603
 604 end:
 605         return ret;
 606 }
 607
 608 /*
 609  * Teardown pid tracker content, but don't free pid_tracker object.
 610  */
 611 static
 612 void fini_pid_tracker(struct ust_pid_tracker *pid_tracker)
 613 {
 614         struct ust_pid_tracker_node *tracker_node;
 615         struct lttng_ht_iter iter;
 616
 617         if (!pid_tracker->ht) {
 618                 return;
 619         }
 620         rcu_read_lock();
 621         cds_lfht_for_each_entry(pid_tracker->ht->ht,
 622                         &iter.iter, tracker_node, node.node) {
 623                 int ret = lttng_ht_del(pid_tracker->ht, &iter);
 624
 625                 assert(!ret);
 626                 destroy_pid_tracker_node(tracker_node);
 627         }
 628         rcu_read_unlock();
 629         ht_cleanup_push(pid_tracker->ht);
 630         pid_tracker->ht = NULL;
 631 }
 632
 633 static
 634 struct ust_pid_tracker_node *pid_tracker_lookup(
 635                 struct ust_pid_tracker *pid_tracker, int pid,
 636                 struct lttng_ht_iter *iter)
 637 {
 638         unsigned long _pid = (unsigned long) pid;
 639         struct lttng_ht_node_ulong *node;
 640
 641         lttng_ht_lookup(pid_tracker->ht, (void *) _pid, iter);
 642         node = lttng_ht_iter_get_node_ulong(iter);
 643         if (node) {
 644                 return caa_container_of(node, struct ust_pid_tracker_node,
 645                         node);
 646         } else {
 647                 return NULL;
 648         }
 649 }
 650
 651 static
 652 int pid_tracker_add_pid(struct ust_pid_tracker *pid_tracker, int pid)
 653 {
 654         int retval = LTTNG_OK;
 655         struct ust_pid_tracker_node *tracker_node;
 656         struct lttng_ht_iter iter;
 657
 658         if (pid < 0) {
 659                 retval = LTTNG_ERR_INVALID;
 660                 goto end;
 661         }
 662         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 663         if (tracker_node) {
 664                 /* Already exists. */
 665                 retval = LTTNG_ERR_PID_TRACKED;
 666                 goto end;
 667         }
 668         tracker_node = zmalloc(sizeof(*tracker_node));
 669         if (!tracker_node) {
 670                 retval = LTTNG_ERR_NOMEM;
 671                 goto end;
 672         }
 673         lttng_ht_node_init_ulong(&tracker_node->node, (unsigned long) pid);
 674         lttng_ht_add_unique_ulong(pid_tracker->ht, &tracker_node->node);
 675 end:
 676         return retval;
 677 }
 678
 679 static
 680 int pid_tracker_del_pid(struct ust_pid_tracker *pid_tracker, int pid)
 681 {
 682         int retval = LTTNG_OK, ret;
 683         struct ust_pid_tracker_node *tracker_node;
 684         struct lttng_ht_iter iter;
 685
 686         if (pid < 0) {
 687                 retval = LTTNG_ERR_INVALID;
 688                 goto end;
 689         }
 690         tracker_node = pid_tracker_lookup(pid_tracker, pid, &iter);
 691         if (!tracker_node) {
 692                 /* Not found */
 693                 retval = LTTNG_ERR_PID_NOT_TRACKED;
 694                 goto end;
 695         }
 696         ret = lttng_ht_del(pid_tracker->ht, &iter);
 697         assert(!ret);
 698
 699         destroy_pid_tracker_node(tracker_node);
 700 end:
 701         return retval;
 702 }
 703
 704 /*
 705  * The session lock is held when calling this function.
 706  */
 707 int trace_ust_pid_tracker_lookup(struct ltt_ust_session *session, int pid)
 708 {
 709         struct lttng_ht_iter iter;
 710
 711         if (!session->pid_tracker.ht) {
 712                 return 1;
 713         }
 714         if (pid_tracker_lookup(&session->pid_tracker, pid, &iter)) {
 715                 return 1;
 716         }
 717         return 0;
 718 }
 719
 720 /*
 721  * Called with the session lock held.
 722  */
 723 int trace_ust_track_pid(struct ltt_ust_session *session, int pid)
 724 {
 725         int retval = LTTNG_OK;
 726
 727         if (pid == -1) {
 728                 /* Track all pids: destroy tracker if exists. */
 729                 if (session->pid_tracker.ht) {
 730                         fini_pid_tracker(&session->pid_tracker);
 731                         /* Ensure all apps have session. */
 732                         ust_app_global_update_all(session);
 733                 }
 734         } else {
 735                 int ret;
 736
 737                 if (!session->pid_tracker.ht) {
 738                         /* Create tracker. */
 739                         if (init_pid_tracker(&session->pid_tracker)) {
 740                                 ERR("Error initializing PID tracker");
 741                                 retval = LTTNG_ERR_NOMEM;
 742                                 goto end;
 743                         }
 744                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 745                         if (ret != LTTNG_OK) {
 746                                 retval = ret;
 747                                 fini_pid_tracker(&session->pid_tracker);
 748                                 goto end;
 749                         }
 750                         /* Remove all apps from session except pid. */
 751                         ust_app_global_update_all(session);
 752                 } else {
 753                         struct ust_app *app;
 754
 755                         ret = pid_tracker_add_pid(&session->pid_tracker, pid);
 756                         if (ret != LTTNG_OK) {
 757                                 retval = ret;
 758                                 goto end;
 759                         }
 760                         /* Add session to application */
 761                         app = ust_app_find_by_pid(pid);
 762                         if (app) {
 763                                 ust_app_global_update(session, app);
 764                         }
 765                 }
 766         }
 767 end:
 768         return retval;
 769 }
 770
 771 /*
 772  * Called with the session lock held.
 773  */
 774 int trace_ust_untrack_pid(struct ltt_ust_session *session, int pid)
 775 {
 776         int retval = LTTNG_OK;
 777
 778         if (pid == -1) {
 779                 /* Create empty tracker, replace old tracker. */
 780                 struct ust_pid_tracker tmp_tracker;
 781
 782                 tmp_tracker = session->pid_tracker;
 783                 if (init_pid_tracker(&session->pid_tracker)) {
 784                         ERR("Error initializing PID tracker");
 785                         retval = LTTNG_ERR_NOMEM;
 786                         /* Rollback operation. */
 787                         session->pid_tracker = tmp_tracker;
 788                         goto end;
 789                 }
 790                 fini_pid_tracker(&tmp_tracker);
 791
 792                 /* Remove session from all applications */
 793                 ust_app_global_update_all(session);
 794         } else {
 795                 int ret;
 796                 struct ust_app *app;
 797
 798                 if (!session->pid_tracker.ht) {
 799                         retval = LTTNG_ERR_INVALID;
 800                         goto end;
 801                 }
 802                 /* Remove PID from tracker */
 803                 ret = pid_tracker_del_pid(&session->pid_tracker, pid);
 804                 if (ret != LTTNG_OK) {
 805                         retval = ret;
 806                         goto end;
 807                 }
 808                 /* Remove session from application. */
 809                 app = ust_app_find_by_pid(pid);
 810                 if (app) {
 811                         ust_app_global_update(session, app);
 812                 }
 813         }
 814 end:
 815         return retval;
 816 }
 817
 818 /*
 819  * Called with session lock held.
 820  */
 821 ssize_t trace_ust_list_tracker_pids(struct ltt_ust_session *session,
 822                 int32_t **_pids)
 823 {
 824         struct ust_pid_tracker_node *tracker_node;
 825         struct lttng_ht_iter iter;
 826         unsigned long count, i = 0;
 827         long approx[2];
 828         int32_t *pids;
 829         int ret = 0;
 830
 831         if (!session->pid_tracker.ht) {
 832                 /* Tracker disabled. Set first entry to -1. */
 833                 pids = zmalloc(sizeof(*pids));
 834                 if (!pids) {
 835                         ret = -1;
 836                         goto end;
 837                 }
 838                 pids[0] = -1;
 839                 *_pids = pids;
 840                 return 1;
 841         }
 842
 843         rcu_read_lock();
 844         cds_lfht_count_nodes(session->pid_tracker.ht->ht,
 845                 &approx[0], &count, &approx[1]);
 846         pids = zmalloc(sizeof(*pids) * count);
 847         if (!pids) {
 848                 ret = -1;
 849                 goto end;
 850         }
 851         cds_lfht_for_each_entry(session->pid_tracker.ht->ht,
 852                         &iter.iter, tracker_node, node.node) {
 853                 pids[i++] = tracker_node->node.key;
 854         }
 855         *_pids = pids;
 856         ret = count;
 857 end:
 858         rcu_read_unlock();
 859         return ret;
 860 }
 861
 862 /*
 863  * RCU safe free context structure.
 864  */
 865 static void destroy_context_rcu(struct rcu_head *head)
 866 {
 867         struct lttng_ht_node_ulong *node =
 868                 caa_container_of(head, struct lttng_ht_node_ulong, head);
 869         struct ltt_ust_context *ctx =
 870                 caa_container_of(node, struct ltt_ust_context, node);
 871
 872         free(ctx);
 873 }
 874
 875 /*
 876  * Cleanup UST context hash table.
 877  */
 878 static void destroy_contexts(struct lttng_ht *ht)
 879 {
 880         int ret;
 881         struct lttng_ht_node_ulong *node;
 882         struct lttng_ht_iter iter;
 883         struct ltt_ust_context *ctx;
 884
 885         assert(ht);
 886
 887         rcu_read_lock();
 888         cds_lfht_for_each_entry(ht->ht, &iter.iter, node, node) {
 889                 /* Remove from ordered list. */
 890                 ctx = caa_container_of(node, struct ltt_ust_context, node);
 891                 cds_list_del(&ctx->list);
 892                 /* Remove from channel's hash table. */
 893                 ret = lttng_ht_del(ht, &iter);
 894                 if (!ret) {
 895                         call_rcu(&node->head, destroy_context_rcu);
 896                 }
 897         }
 898         rcu_read_unlock();
 899
 900         ht_cleanup_push(ht);
 901 }
 902
 903 /*
 904  * Cleanup ust event structure.
 905  */
 906 void trace_ust_destroy_event(struct ltt_ust_event *event)
 907 {
 908         assert(event);
 909
 910         DBG2("Trace destroy UST event %s", event->attr.name);
 911         free(event->filter_expression);
 912         free(event->filter);
 913         free(event->exclusion);
 914         free(event);
 915 }
 916
 917 /*
 918  * URCU intermediate call to complete destroy event.
 919  */
 920 static void destroy_event_rcu(struct rcu_head *head)
 921 {
 922         struct lttng_ht_node_str *node =
 923                 caa_container_of(head, struct lttng_ht_node_str, head);
 924         struct ltt_ust_event *event =
 925                 caa_container_of(node, struct ltt_ust_event, node);
 926
 927         trace_ust_destroy_event(event);
 928 }
 929
 930 /*
 931  * Cleanup UST events hashtable.
 932  */
 933 static void destroy_events(struct lttng_ht *events)
 934 {
 935         int ret;
 936         struct lttng_ht_node_str *node;
 937         struct lttng_ht_iter iter;
 938
 939         assert(events);
 940
 941         rcu_read_lock();
 942         cds_lfht_for_each_entry(events->ht, &iter.iter, node, node) {
 943                 ret = lttng_ht_del(events, &iter);
 944                 assert(!ret);
 945                 call_rcu(&node->head, destroy_event_rcu);
 946         }
 947         rcu_read_unlock();
 948
 949         ht_cleanup_push(events);
 950 }
 951
 952 /*
 953  * Cleanup ust channel structure.
 954  *
 955  * Should _NOT_ be called with RCU read lock held.
 956  */
 957 static void _trace_ust_destroy_channel(struct ltt_ust_channel *channel)
 958 {
 959         assert(channel);
 960
 961         DBG2("Trace destroy UST channel %s", channel->name);
 962
 963         /* Destroying all events of the channel */
 964         destroy_events(channel->events);
 965         /* Destroying all context of the channel */
 966         destroy_contexts(channel->ctx);
 967
 968         free(channel);
 969 }
 970
 971 /*
 972  * URCU intermediate call to complete destroy channel.
 973  */
 974 static void destroy_channel_rcu(struct rcu_head *head)
 975 {
 976         struct lttng_ht_node_str *node =
 977                 caa_container_of(head, struct lttng_ht_node_str, head);
 978         struct ltt_ust_channel *channel =
 979                 caa_container_of(node, struct ltt_ust_channel, node);
 980
 981         _trace_ust_destroy_channel(channel);
 982 }
 983
 984 void trace_ust_destroy_channel(struct ltt_ust_channel *channel)
 985 {
 986         call_rcu(&channel->node.head, destroy_channel_rcu);
 987 }
 988
 989 /*
 990  * Remove an UST channel from a channel HT.
 991  */
 992 void trace_ust_delete_channel(struct lttng_ht *ht,
 993                 struct ltt_ust_channel *channel)
 994 {
 995         int ret;
 996         struct lttng_ht_iter iter;
 997
 998         assert(ht);
 999         assert(channel);
1000
1001         iter.iter.node = &channel->node.node;
1002         ret = lttng_ht_del(ht, &iter);
1003         assert(!ret);
1004 }
1005
1006 /*
1007  * Iterate over a hash table containing channels and cleanup safely.
1008  */
1009 static void destroy_channels(struct lttng_ht *channels)
1010 {
1011         int ret;
1012         struct lttng_ht_node_str *node;
1013         struct lttng_ht_iter iter;
1014
1015         assert(channels);
1016
1017         rcu_read_lock();
1018
1019         cds_lfht_for_each_entry(channels->ht, &iter.iter, node, node) {
1020                 ret = lttng_ht_del(channels, &iter);
1021                 assert(!ret);
1022                 call_rcu(&node->head, destroy_channel_rcu);
1023         }
1024         rcu_read_unlock();
1025
1026         ht_cleanup_push(channels);
1027 }
1028
1029 /*
1030  * Cleanup UST global domain.
1031  */
1032 static void destroy_domain_global(struct ltt_ust_domain_global *dom)
1033 {
1034         assert(dom);
1035
1036         destroy_channels(dom->channels);
1037 }
1038
1039 /*
1040  * Cleanup ust session structure
1041  *
1042  * Should *NOT* be called with RCU read-side lock held.
1043  */
1044 void trace_ust_destroy_session(struct ltt_ust_session *session)
1045 {
1046         struct agent *agt;
1047         struct buffer_reg_uid *reg, *sreg;
1048         struct lttng_ht_iter iter;
1049
1050         assert(session);
1051
1052         DBG2("Trace UST destroy session %" PRIu64, session->id);
1053
1054         /* Cleaning up UST domain */
1055         destroy_domain_global(&session->domain_global);
1056
1057         rcu_read_lock();
1058         cds_lfht_for_each_entry(session->agents->ht, &iter.iter, agt, node.node) {
1059                 int ret = lttng_ht_del(session->agents, &iter);
1060
1061                 assert(!ret);
1062                 agent_destroy(agt);
1063         }
1064         rcu_read_unlock();
1065
1066         ht_cleanup_push(session->agents);
1067
1068         /* Cleanup UID buffer registry object(s). */
1069         cds_list_for_each_entry_safe(reg, sreg, &session->buffer_reg_uid_list,
1070                         lnode) {
1071                 cds_list_del(&reg->lnode);
1072                 buffer_reg_uid_remove(reg);
1073                 buffer_reg_uid_destroy(reg, session->consumer);
1074         }
1075
1076         consumer_destroy_output(session->consumer);
1077         consumer_destroy_output(session->tmp_consumer);
1078
1079         fini_pid_tracker(&session->pid_tracker);
1080
1081         free(session);
1082 }