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