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

   1 /*
   2  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #define _LGPL_SOURCE
   9 #include <assert.h>
  10 #include <inttypes.h>
  11
  12 #include <common/common.h>
  13 #include <common/hashtable/utils.h>
  14 #include <lttng/lttng.h>
  15
  16 #include "ust-registry.h"
  17 #include "ust-app.h"
  18 #include "ust-field-utils.h"
  19 #include "utils.h"
  20 #include "lttng-sessiond.h"
  21 #include "notification-thread-commands.h"
  22
  23
  24 /*
  25  * Hash table match function for event in the registry.
  26  */
  27 static int ht_match_event(struct cds_lfht_node *node, const void *_key)
  28 {
  29         const struct ust_registry_event *key;
  30         struct ust_registry_event *event;
  31         int i;
  32
  33         assert(node);
  34         assert(_key);
  35
  36         event = caa_container_of(node, struct ust_registry_event, node.node);
  37         assert(event);
  38         key = _key;
  39
  40         /* It has to be a perfect match. First, compare the event names. */
  41         if (strncmp(event->name, key->name, sizeof(event->name))) {
  42                 goto no_match;
  43         }
  44
  45         /* Compare log levels. */
  46         if (event->loglevel_value != key->loglevel_value) {
  47                 goto no_match;
  48         }
  49
  50         /* Compare the number of fields. */
  51         if (event->nr_fields != key->nr_fields) {
  52                 goto no_match;
  53         }
  54
  55         /* Compare each field individually. */
  56         for (i = 0; i < event->nr_fields; i++) {
  57                 if (!match_ustctl_field(&event->fields[i], &key->fields[i])) {
  58                         goto no_match;
  59                 }
  60         }
  61
  62         /* Compare model URI. */
  63         if (event->model_emf_uri != NULL && key->model_emf_uri == NULL) {
  64                 goto no_match;
  65         } else if(event->model_emf_uri == NULL && key->model_emf_uri != NULL) {
  66                 goto no_match;
  67         } else if (event->model_emf_uri != NULL && key->model_emf_uri != NULL) {
  68                 if (strcmp(event->model_emf_uri, key->model_emf_uri)) {
  69                         goto no_match;
  70                 }
  71         }
  72
  73         /* Match */
  74         return 1;
  75
  76 no_match:
  77         return 0;
  78 }
  79
  80 static unsigned long ht_hash_event(const void *_key, unsigned long seed)
  81 {
  82         uint64_t hashed_key;
  83         const struct ust_registry_event *key = _key;
  84
  85         assert(key);
  86
  87         hashed_key = (uint64_t) hash_key_str(key->name, seed);
  88
  89         return hash_key_u64(&hashed_key, seed);
  90 }
  91
  92 static int compare_enums(const struct ust_registry_enum *reg_enum_a,
  93                 const struct ust_registry_enum *reg_enum_b)
  94 {
  95         int ret = 0;
  96         size_t i;
  97
  98         assert(strcmp(reg_enum_a->name, reg_enum_b->name) == 0);
  99         if (reg_enum_a->nr_entries != reg_enum_b->nr_entries) {
 100                 ret = -1;
 101                 goto end;
 102         }
 103         for (i = 0; i < reg_enum_a->nr_entries; i++) {
 104                 const struct ustctl_enum_entry *entries_a, *entries_b;
 105
 106                 entries_a = &reg_enum_a->entries[i];
 107                 entries_b = &reg_enum_b->entries[i];
 108                 if (entries_a->start.value != entries_b->start.value) {
 109                         ret = -1;
 110                         goto end;
 111                 }
 112                 if (entries_a->end.value != entries_b->end.value) {
 113                         ret = -1;
 114                         goto end;
 115                 }
 116                 if (entries_a->start.signedness != entries_b->start.signedness) {
 117                         ret = -1;
 118                         goto end;
 119                 }
 120                 if (entries_a->end.signedness != entries_b->end.signedness) {
 121                         ret = -1;
 122                         goto end;
 123                 }
 124
 125                 if (strcmp(entries_a->string, entries_b->string)) {
 126                         ret = -1;
 127                         goto end;
 128                 }
 129         }
 130 end:
 131         return ret;
 132 }
 133
 134 /*
 135  * Hash table match function for enumerations in the session. Match is
 136  * performed on enumeration name, and confirmed by comparing the enum
 137  * entries.
 138  */
 139 static int ht_match_enum(struct cds_lfht_node *node, const void *_key)
 140 {
 141         struct ust_registry_enum *_enum;
 142         const struct ust_registry_enum *key;
 143
 144         assert(node);
 145         assert(_key);
 146
 147         _enum = caa_container_of(node, struct ust_registry_enum,
 148                         node.node);
 149         assert(_enum);
 150         key = _key;
 151
 152         if (strncmp(_enum->name, key->name, LTTNG_UST_SYM_NAME_LEN)) {
 153                 goto no_match;
 154         }
 155         if (compare_enums(_enum, key)) {
 156                 goto no_match;
 157         }
 158
 159         /* Match. */
 160         return 1;
 161
 162 no_match:
 163         return 0;
 164 }
 165
 166 /*
 167  * Hash table match function for enumerations in the session. Match is
 168  * performed by enumeration ID.
 169  */
 170 static int ht_match_enum_id(struct cds_lfht_node *node, const void *_key)
 171 {
 172         struct ust_registry_enum *_enum;
 173         const struct ust_registry_enum *key = _key;
 174
 175         assert(node);
 176         assert(_key);
 177
 178         _enum = caa_container_of(node, struct ust_registry_enum, node.node);
 179         assert(_enum);
 180
 181         if (_enum->id != key->id) {
 182                 goto no_match;
 183         }
 184
 185         /* Match. */
 186         return 1;
 187
 188 no_match:
 189         return 0;
 190 }
 191
 192 /*
 193  * Hash table hash function for enumerations in the session. The
 194  * enumeration name is used for hashing.
 195  */
 196 static unsigned long ht_hash_enum(void *_key, unsigned long seed)
 197 {
 198         struct ust_registry_enum *key = _key;
 199
 200         assert(key);
 201         return hash_key_str(key->name, seed);
 202 }
 203
 204 /*
 205  * Return negative value on error, 0 if OK.
 206  *
 207  * TODO: we could add stricter verification of more types to catch
 208  * errors in liblttng-ust implementation earlier than consumption by the
 209  * trace reader.
 210  */
 211 static
 212 int validate_event_field(struct ustctl_field *field,
 213                 const char *event_name,
 214                 struct ust_app *app)
 215 {
 216         int ret = 0;
 217
 218         switch(field->type.atype) {
 219         case ustctl_atype_integer:
 220         case ustctl_atype_enum:
 221         case ustctl_atype_array:
 222         case ustctl_atype_sequence:
 223         case ustctl_atype_string:
 224         case ustctl_atype_variant:
 225         case ustctl_atype_array_nestable:
 226         case ustctl_atype_sequence_nestable:
 227         case ustctl_atype_enum_nestable:
 228         case ustctl_atype_variant_nestable:
 229                 break;
 230         case ustctl_atype_struct:
 231                 if (field->type.u.legacy._struct.nr_fields != 0) {
 232                         WARN("Unsupported non-empty struct field.");
 233                         ret = -EINVAL;
 234                         goto end;
 235                 }
 236                 break;
 237         case ustctl_atype_struct_nestable:
 238                 if (field->type.u.struct_nestable.nr_fields != 0) {
 239                         WARN("Unsupported non-empty struct field.");
 240                         ret = -EINVAL;
 241                         goto end;
 242                 }
 243                 break;
 244
 245         case ustctl_atype_float:
 246                 switch (field->type.u._float.mant_dig) {
 247                 case 0:
 248                         WARN("UST application '%s' (pid: %d) has unknown float mantissa '%u' "
 249                                 "in field '%s', rejecting event '%s'",
 250                                 app->name, app->pid,
 251                                 field->type.u._float.mant_dig,
 252                                 field->name,
 253                                 event_name);
 254                         ret = -EINVAL;
 255                         goto end;
 256                 default:
 257                         break;
 258                 }
 259                 break;
 260
 261         default:
 262                 ret = -ENOENT;
 263                 goto end;
 264         }
 265 end:
 266         return ret;
 267 }
 268
 269 static
 270 int validate_event_fields(size_t nr_fields, struct ustctl_field *fields,
 271                 const char *event_name, struct ust_app *app)
 272 {
 273         unsigned int i;
 274
 275         for (i = 0; i < nr_fields; i++) {
 276                 if (validate_event_field(&fields[i], event_name, app) < 0)
 277                         return -EINVAL;
 278         }
 279         return 0;
 280 }
 281
 282 /*
 283  * Allocate event and initialize it. This does NOT set a valid event id from a
 284  * registry.
 285  */
 286 static struct ust_registry_event *alloc_event(int session_objd,
 287                 int channel_objd, char *name, char *sig, size_t nr_fields,
 288                 struct ustctl_field *fields, int loglevel_value,
 289                 char *model_emf_uri, struct ust_app *app)
 290 {
 291         struct ust_registry_event *event = NULL;
 292
 293         /*
 294          * Ensure that the field content is valid.
 295          */
 296         if (validate_event_fields(nr_fields, fields, name, app) < 0) {
 297                 return NULL;
 298         }
 299
 300         event = zmalloc(sizeof(*event));
 301         if (!event) {
 302                 PERROR("zmalloc ust registry event");
 303                 goto error;
 304         }
 305
 306         event->session_objd = session_objd;
 307         event->channel_objd = channel_objd;
 308         /* Allocated by ustctl. */
 309         event->signature = sig;
 310         event->nr_fields = nr_fields;
 311         event->fields = fields;
 312         event->loglevel_value = loglevel_value;
 313         event->model_emf_uri = model_emf_uri;
 314         if (name) {
 315                 /* Copy event name and force NULL byte. */
 316                 strncpy(event->name, name, sizeof(event->name));
 317                 event->name[sizeof(event->name) - 1] = '\0';
 318         }
 319         cds_lfht_node_init(&event->node.node);
 320
 321 error:
 322         return event;
 323 }
 324
 325 /*
 326  * Free event data structure. This does NOT delete it from any hash table. It's
 327  * safe to pass a NULL pointer. This shoudl be called inside a call RCU if the
 328  * event is previously deleted from a rcu hash table.
 329  */
 330 static void destroy_event(struct ust_registry_event *event)
 331 {
 332         if (!event) {
 333                 return;
 334         }
 335
 336         free(event->fields);
 337         free(event->model_emf_uri);
 338         free(event->signature);
 339         free(event);
 340 }
 341
 342 /*
 343  * Destroy event function call of the call RCU.
 344  */
 345 static void destroy_event_rcu(struct rcu_head *head)
 346 {
 347         struct lttng_ht_node_u64 *node =
 348                 caa_container_of(head, struct lttng_ht_node_u64, head);
 349         struct ust_registry_event *event =
 350                 caa_container_of(node, struct ust_registry_event, node);
 351
 352         destroy_event(event);
 353 }
 354
 355 /*
 356  * Find an event using the name and signature in the given registry. RCU read
 357  * side lock MUST be acquired before calling this function and as long as the
 358  * event reference is kept by the caller.
 359  *
 360  * On success, the event pointer is returned else NULL.
 361  */
 362 struct ust_registry_event *ust_registry_find_event(
 363                 struct ust_registry_channel *chan, char *name, char *sig)
 364 {
 365         struct lttng_ht_node_u64 *node;
 366         struct lttng_ht_iter iter;
 367         struct ust_registry_event *event = NULL;
 368         struct ust_registry_event key;
 369
 370         assert(chan);
 371         assert(name);
 372         assert(sig);
 373
 374         /* Setup key for the match function. */
 375         strncpy(key.name, name, sizeof(key.name));
 376         key.name[sizeof(key.name) - 1] = '\0';
 377         key.signature = sig;
 378
 379         cds_lfht_lookup(chan->ht->ht, chan->ht->hash_fct(&key, lttng_ht_seed),
 380                         chan->ht->match_fct, &key, &iter.iter);
 381         node = lttng_ht_iter_get_node_u64(&iter);
 382         if (!node) {
 383                 goto end;
 384         }
 385         event = caa_container_of(node, struct ust_registry_event, node);
 386
 387 end:
 388         return event;
 389 }
 390
 391 /*
 392  * Create a ust_registry_event from the given parameters and add it to the
 393  * registry hash table. If event_id is valid, it is set with the newly created
 394  * event id.
 395  *
 396  * On success, return 0 else a negative value. The created event MUST be unique
 397  * so on duplicate entry -EINVAL is returned. On error, event_id is untouched.
 398  *
 399  * Should be called with session registry mutex held.
 400  */
 401 int ust_registry_create_event(struct ust_registry_session *session,
 402                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 403                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 404                 int loglevel_value, char *model_emf_uri, int buffer_type,
 405                 uint32_t *event_id_p, struct ust_app *app)
 406 {
 407         int ret;
 408         uint32_t event_id;
 409         struct cds_lfht_node *nptr;
 410         struct ust_registry_event *event = NULL;
 411         struct ust_registry_channel *chan;
 412
 413         assert(session);
 414         assert(name);
 415         assert(sig);
 416         assert(event_id_p);
 417
 418         rcu_read_lock();
 419
 420         /*
 421          * This should not happen but since it comes from the UST tracer, an
 422          * external party, don't assert and simply validate values.
 423          */
 424         if (session_objd < 0 || channel_objd < 0) {
 425                 ret = -EINVAL;
 426                 goto error_free;
 427         }
 428
 429         chan = ust_registry_channel_find(session, chan_key);
 430         if (!chan) {
 431                 ret = -EINVAL;
 432                 goto error_free;
 433         }
 434
 435         /* Check if we've reached the maximum possible id. */
 436         if (ust_registry_is_max_id(chan->used_event_id)) {
 437                 ret = -ENOENT;
 438                 goto error_free;
 439         }
 440
 441         event = alloc_event(session_objd, channel_objd, name, sig, nr_fields,
 442                         fields, loglevel_value, model_emf_uri, app);
 443         if (!event) {
 444                 ret = -ENOMEM;
 445                 goto error_free;
 446         }
 447
 448         DBG3("UST registry creating event with event: %s, sig: %s, id: %u, "
 449                         "chan_objd: %u, sess_objd: %u, chan_id: %u", event->name,
 450                         event->signature, event->id, event->channel_objd,
 451                         event->session_objd, chan->chan_id);
 452
 453         /*
 454          * This is an add unique with a custom match function for event. The node
 455          * are matched using the event name and signature.
 456          */
 457         nptr = cds_lfht_add_unique(chan->ht->ht, chan->ht->hash_fct(event,
 458                                 lttng_ht_seed), chan->ht->match_fct, event, &event->node.node);
 459         if (nptr != &event->node.node) {
 460                 if (buffer_type == LTTNG_BUFFER_PER_UID) {
 461                         /*
 462                          * This is normal, we just have to send the event id of the
 463                          * returned node and make sure we destroy the previously allocated
 464                          * event object.
 465                          */
 466                         destroy_event(event);
 467                         event = caa_container_of(nptr, struct ust_registry_event,
 468                                         node.node);
 469                         assert(event);
 470                         event_id = event->id;
 471                 } else {
 472                         ERR("UST registry create event add unique failed for event: %s, "
 473                                         "sig: %s, id: %u, chan_objd: %u, sess_objd: %u",
 474                                         event->name, event->signature, event->id,
 475                                         event->channel_objd, event->session_objd);
 476                         ret = -EINVAL;
 477                         goto error_unlock;
 478                 }
 479         } else {
 480                 /* Request next event id if the node was successfully added. */
 481                 event_id = event->id = ust_registry_get_next_event_id(chan);
 482         }
 483
 484         *event_id_p = event_id;
 485
 486         if (!event->metadata_dumped) {
 487                 /* Append to metadata */
 488                 ret = ust_metadata_event_statedump(session, chan, event);
 489                 if (ret) {
 490                         ERR("Error appending event metadata (errno = %d)", ret);
 491                         rcu_read_unlock();
 492                         return ret;
 493                 }
 494         }
 495
 496         rcu_read_unlock();
 497         return 0;
 498
 499 error_free:
 500         free(sig);
 501         free(fields);
 502         free(model_emf_uri);
 503 error_unlock:
 504         rcu_read_unlock();
 505         destroy_event(event);
 506         return ret;
 507 }
 508
 509 /*
 510  * For a given event in a registry, delete the entry and destroy the event.
 511  * This MUST be called within a RCU read side lock section.
 512  */
 513 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 514                 struct ust_registry_event *event)
 515 {
 516         int ret;
 517         struct lttng_ht_iter iter;
 518
 519         assert(chan);
 520         assert(event);
 521
 522         /* Delete the node first. */
 523         iter.iter.node = &event->node.node;
 524         ret = lttng_ht_del(chan->ht, &iter);
 525         assert(!ret);
 526
 527         call_rcu(&event->node.head, destroy_event_rcu);
 528
 529         return;
 530 }
 531
 532 static void destroy_enum(struct ust_registry_enum *reg_enum)
 533 {
 534         if (!reg_enum) {
 535                 return;
 536         }
 537         free(reg_enum->entries);
 538         free(reg_enum);
 539 }
 540
 541 static void destroy_enum_rcu(struct rcu_head *head)
 542 {
 543         struct ust_registry_enum *reg_enum =
 544                 caa_container_of(head, struct ust_registry_enum, rcu_head);
 545
 546         destroy_enum(reg_enum);
 547 }
 548
 549 /*
 550  * Lookup enumeration by name and comparing enumeration entries.
 551  * Needs to be called from RCU read-side critical section.
 552  */
 553 static struct ust_registry_enum *ust_registry_lookup_enum(
 554                 struct ust_registry_session *session,
 555                 const struct ust_registry_enum *reg_enum_lookup)
 556 {
 557         struct ust_registry_enum *reg_enum = NULL;
 558         struct lttng_ht_node_str *node;
 559         struct lttng_ht_iter iter;
 560
 561         cds_lfht_lookup(session->enums->ht,
 562                         ht_hash_enum((void *) reg_enum_lookup, lttng_ht_seed),
 563                         ht_match_enum, reg_enum_lookup, &iter.iter);
 564         node = lttng_ht_iter_get_node_str(&iter);
 565         if (!node) {
 566                 goto end;
 567         }
 568         reg_enum = caa_container_of(node, struct ust_registry_enum, node);
 569 end:
 570         return reg_enum;
 571 }
 572
 573 /*
 574  * Lookup enumeration by enum ID.
 575  * Needs to be called from RCU read-side critical section.
 576  */
 577 struct ust_registry_enum *
 578         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 579                 const char *enum_name, uint64_t enum_id)
 580 {
 581         struct ust_registry_enum *reg_enum = NULL;
 582         struct lttng_ht_node_str *node;
 583         struct lttng_ht_iter iter;
 584         struct ust_registry_enum reg_enum_lookup;
 585
 586         memset(&reg_enum_lookup, 0, sizeof(reg_enum_lookup));
 587         strncpy(reg_enum_lookup.name, enum_name, LTTNG_UST_SYM_NAME_LEN);
 588         reg_enum_lookup.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 589         reg_enum_lookup.id = enum_id;
 590         cds_lfht_lookup(session->enums->ht,
 591                         ht_hash_enum((void *) &reg_enum_lookup, lttng_ht_seed),
 592                         ht_match_enum_id, &reg_enum_lookup, &iter.iter);
 593         node = lttng_ht_iter_get_node_str(&iter);
 594         if (!node) {
 595                 goto end;
 596         }
 597         reg_enum = caa_container_of(node, struct ust_registry_enum, node);
 598 end:
 599         return reg_enum;
 600 }
 601
 602 /*
 603  * Create a ust_registry_enum from the given parameters and add it to the
 604  * registry hash table, or find it if already there.
 605  *
 606  * On success, return 0 else a negative value.
 607  *
 608  * Should be called with session registry mutex held.
 609  *
 610  * We receive ownership of entries.
 611  */
 612 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 613                 int session_objd, char *enum_name,
 614                 struct ustctl_enum_entry *entries, size_t nr_entries,
 615                 uint64_t *enum_id)
 616 {
 617         int ret = 0;
 618         struct cds_lfht_node *nodep;
 619         struct ust_registry_enum *reg_enum = NULL, *old_reg_enum;
 620
 621         assert(session);
 622         assert(enum_name);
 623
 624         rcu_read_lock();
 625
 626         /*
 627          * This should not happen but since it comes from the UST tracer, an
 628          * external party, don't assert and simply validate values.
 629          */
 630         if (session_objd < 0) {
 631                 ret = -EINVAL;
 632                 goto end;
 633         }
 634
 635         /* Check if the enumeration was already dumped */
 636         reg_enum = zmalloc(sizeof(*reg_enum));
 637         if (!reg_enum) {
 638                 PERROR("zmalloc ust registry enumeration");
 639                 ret = -ENOMEM;
 640                 goto end;
 641         }
 642         strncpy(reg_enum->name, enum_name, LTTNG_UST_SYM_NAME_LEN);
 643         reg_enum->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 644         /* entries will be owned by reg_enum. */
 645         reg_enum->entries = entries;
 646         reg_enum->nr_entries = nr_entries;
 647         entries = NULL;
 648
 649         old_reg_enum = ust_registry_lookup_enum(session, reg_enum);
 650         if (old_reg_enum) {
 651                 DBG("enum %s already in sess_objd: %u", enum_name, session_objd);
 652                 /* Fall through. Use prior enum. */
 653                 destroy_enum(reg_enum);
 654                 reg_enum = old_reg_enum;
 655         } else {
 656                 DBG("UST registry creating enum: %s, sess_objd: %u",
 657                                 enum_name, session_objd);
 658                 if (session->next_enum_id == -1ULL) {
 659                         ret = -EOVERFLOW;
 660                         destroy_enum(reg_enum);
 661                         goto end;
 662                 }
 663                 reg_enum->id = session->next_enum_id++;
 664                 cds_lfht_node_init(&reg_enum->node.node);
 665                 nodep = cds_lfht_add_unique(session->enums->ht,
 666                                 ht_hash_enum(reg_enum, lttng_ht_seed),
 667                                 ht_match_enum_id, reg_enum,
 668                                 &reg_enum->node.node);
 669                 assert(nodep == &reg_enum->node.node);
 670         }
 671         DBG("UST registry reply with enum %s with id %" PRIu64 " in sess_objd: %u",
 672                         enum_name, reg_enum->id, session_objd);
 673         *enum_id = reg_enum->id;
 674 end:
 675         free(entries);
 676         rcu_read_unlock();
 677         return ret;
 678 }
 679
 680 /*
 681  * For a given enumeration in a registry, delete the entry and destroy
 682  * the enumeration.
 683  * This MUST be called within a RCU read side lock section.
 684  */
 685 static void ust_registry_destroy_enum(struct ust_registry_session *reg_session,
 686                 struct ust_registry_enum *reg_enum)
 687 {
 688         int ret;
 689         struct lttng_ht_iter iter;
 690
 691         assert(reg_session);
 692         assert(reg_enum);
 693
 694         /* Delete the node first. */
 695         iter.iter.node = &reg_enum->node.node;
 696         ret = lttng_ht_del(reg_session->enums, &iter);
 697         assert(!ret);
 698         call_rcu(&reg_enum->rcu_head, destroy_enum_rcu);
 699 }
 700
 701 /*
 702  * We need to execute ht_destroy outside of RCU read-side critical
 703  * section and outside of call_rcu thread, so we postpone its execution
 704  * using ht_cleanup_push. It is simpler than to change the semantic of
 705  * the many callers of delete_ust_app_session().
 706  */
 707 static
 708 void destroy_channel_rcu(struct rcu_head *head)
 709 {
 710         struct ust_registry_channel *chan =
 711                 caa_container_of(head, struct ust_registry_channel, rcu_head);
 712
 713         if (chan->ht) {
 714                 ht_cleanup_push(chan->ht);
 715         }
 716         free(chan->ctx_fields);
 717         free(chan);
 718 }
 719
 720 /*
 721  * Destroy every element of the registry and free the memory. This does NOT
 722  * free the registry pointer since it might not have been allocated before so
 723  * it's the caller responsability.
 724  */
 725 static void destroy_channel(struct ust_registry_channel *chan, bool notif)
 726 {
 727         struct lttng_ht_iter iter;
 728         struct ust_registry_event *event;
 729         enum lttng_error_code cmd_ret;
 730
 731         assert(chan);
 732
 733         if (notif) {
 734                 cmd_ret = notification_thread_command_remove_channel(
 735                                 notification_thread_handle, chan->consumer_key,
 736                                 LTTNG_DOMAIN_UST);
 737                 if (cmd_ret != LTTNG_OK) {
 738                         ERR("Failed to remove channel from notification thread");
 739                 }
 740         }
 741
 742         if (chan->ht) {
 743                 rcu_read_lock();
 744                 /* Destroy all event associated with this registry. */
 745                 cds_lfht_for_each_entry(
 746                                 chan->ht->ht, &iter.iter, event, node.node) {
 747                         /* Delete the node from the ht and free it. */
 748                         ust_registry_destroy_event(chan, event);
 749                 }
 750                 rcu_read_unlock();
 751         }
 752         call_rcu(&chan->rcu_head, destroy_channel_rcu);
 753 }
 754
 755 /*
 756  * Initialize registry with default values.
 757  */
 758 int ust_registry_channel_add(struct ust_registry_session *session,
 759                 uint64_t key)
 760 {
 761         int ret = 0;
 762         struct ust_registry_channel *chan;
 763
 764         assert(session);
 765
 766         chan = zmalloc(sizeof(*chan));
 767         if (!chan) {
 768                 PERROR("zmalloc ust registry channel");
 769                 ret = -ENOMEM;
 770                 goto error_alloc;
 771         }
 772
 773         chan->ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 774         if (!chan->ht) {
 775                 ret = -ENOMEM;
 776                 goto error;
 777         }
 778
 779         /* Set custom match function. */
 780         chan->ht->match_fct = ht_match_event;
 781         chan->ht->hash_fct = ht_hash_event;
 782
 783         /*
 784          * Assign a channel ID right now since the event notification comes
 785          * *before* the channel notify so the ID needs to be set at this point so
 786          * the metadata can be dumped for that event.
 787          */
 788         if (ust_registry_is_max_id(session->used_channel_id)) {
 789                 ret = -1;
 790                 goto error;
 791         }
 792         chan->chan_id = ust_registry_get_next_chan_id(session);
 793
 794         rcu_read_lock();
 795         lttng_ht_node_init_u64(&chan->node, key);
 796         lttng_ht_add_unique_u64(session->channels, &chan->node);
 797         rcu_read_unlock();
 798
 799         return 0;
 800
 801 error:
 802         destroy_channel(chan, false);
 803 error_alloc:
 804         return ret;
 805 }
 806
 807 /*
 808  * Find a channel in the given registry. RCU read side lock MUST be acquired
 809  * before calling this function and as long as the event reference is kept by
 810  * the caller.
 811  *
 812  * On success, the pointer is returned else NULL.
 813  */
 814 struct ust_registry_channel *ust_registry_channel_find(
 815                 struct ust_registry_session *session, uint64_t key)
 816 {
 817         struct lttng_ht_node_u64 *node;
 818         struct lttng_ht_iter iter;
 819         struct ust_registry_channel *chan = NULL;
 820
 821         assert(session);
 822         assert(session->channels);
 823
 824         DBG3("UST registry channel finding key %" PRIu64, key);
 825
 826         lttng_ht_lookup(session->channels, &key, &iter);
 827         node = lttng_ht_iter_get_node_u64(&iter);
 828         if (!node) {
 829                 goto end;
 830         }
 831         chan = caa_container_of(node, struct ust_registry_channel, node);
 832
 833 end:
 834         return chan;
 835 }
 836
 837 /*
 838  * Remove channel using key from registry and free memory.
 839  */
 840 void ust_registry_channel_del_free(struct ust_registry_session *session,
 841                 uint64_t key, bool notif)
 842 {
 843         struct lttng_ht_iter iter;
 844         struct ust_registry_channel *chan;
 845         int ret;
 846
 847         assert(session);
 848
 849         rcu_read_lock();
 850         chan = ust_registry_channel_find(session, key);
 851         if (!chan) {
 852                 rcu_read_unlock();
 853                 goto end;
 854         }
 855
 856         iter.iter.node = &chan->node.node;
 857         ret = lttng_ht_del(session->channels, &iter);
 858         assert(!ret);
 859         rcu_read_unlock();
 860         destroy_channel(chan, notif);
 861
 862 end:
 863         return;
 864 }
 865
 866 /*
 867  * Initialize registry with default values and set the newly allocated session
 868  * pointer to sessionp.
 869  *
 870  * Return 0 on success and sessionp is set or else return -1 and sessionp is
 871  * kept untouched.
 872  */
 873 int ust_registry_session_init(struct ust_registry_session **sessionp,
 874                 struct ust_app *app,
 875                 uint32_t bits_per_long,
 876                 uint32_t uint8_t_alignment,
 877                 uint32_t uint16_t_alignment,
 878                 uint32_t uint32_t_alignment,
 879                 uint32_t uint64_t_alignment,
 880                 uint32_t long_alignment,
 881                 int byte_order,
 882                 uint32_t major,
 883                 uint32_t minor,
 884                 const char *root_shm_path,
 885                 const char *shm_path,
 886                 uid_t euid,
 887                 gid_t egid,
 888                 uint64_t tracing_id,
 889                 uid_t tracing_uid)
 890 {
 891         int ret;
 892         struct ust_registry_session *session;
 893
 894         assert(sessionp);
 895
 896         session = zmalloc(sizeof(*session));
 897         if (!session) {
 898                 PERROR("zmalloc ust registry session");
 899                 goto error_alloc;
 900         }
 901
 902         pthread_mutex_init(&session->lock, NULL);
 903         session->bits_per_long = bits_per_long;
 904         session->uint8_t_alignment = uint8_t_alignment;
 905         session->uint16_t_alignment = uint16_t_alignment;
 906         session->uint32_t_alignment = uint32_t_alignment;
 907         session->uint64_t_alignment = uint64_t_alignment;
 908         session->long_alignment = long_alignment;
 909         session->byte_order = byte_order;
 910         session->metadata_fd = -1;
 911         session->uid = euid;
 912         session->gid = egid;
 913         session->next_enum_id = 0;
 914         session->major = major;
 915         session->minor = minor;
 916         strncpy(session->root_shm_path, root_shm_path,
 917                 sizeof(session->root_shm_path));
 918         session->root_shm_path[sizeof(session->root_shm_path) - 1] = '\0';
 919         if (shm_path[0]) {
 920                 strncpy(session->shm_path, shm_path,
 921                         sizeof(session->shm_path));
 922                 session->shm_path[sizeof(session->shm_path) - 1] = '\0';
 923                 strncpy(session->metadata_path, shm_path,
 924                         sizeof(session->metadata_path));
 925                 session->metadata_path[sizeof(session->metadata_path) - 1] = '\0';
 926                 strncat(session->metadata_path, "/metadata",
 927                         sizeof(session->metadata_path)
 928                                 - strlen(session->metadata_path) - 1);
 929         }
 930         if (session->shm_path[0]) {
 931                 ret = run_as_mkdir_recursive(session->shm_path,
 932                         S_IRWXU | S_IRWXG,
 933                         euid, egid);
 934                 if (ret) {
 935                         PERROR("run_as_mkdir_recursive");
 936                         goto error;
 937                 }
 938         }
 939         if (session->metadata_path[0]) {
 940                 /* Create metadata file */
 941                 ret = run_as_open(session->metadata_path,
 942                         O_WRONLY | O_CREAT | O_EXCL,
 943                         S_IRUSR | S_IWUSR, euid, egid);
 944                 if (ret < 0) {
 945                         PERROR("Opening metadata file");
 946                         goto error;
 947                 }
 948                 session->metadata_fd = ret;
 949         }
 950
 951         session->enums = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 952         if (!session->enums) {
 953                 ERR("Failed to create enums hash table");
 954                 goto error;
 955         }
 956         /* hash/match functions are specified at call site. */
 957         session->enums->match_fct = NULL;
 958         session->enums->hash_fct = NULL;
 959
 960         session->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 961         if (!session->channels) {
 962                 goto error;
 963         }
 964
 965         ret = lttng_uuid_generate(session->uuid);
 966         if (ret) {
 967                 ERR("Failed to generate UST uuid (errno = %d)", ret);
 968                 goto error;
 969         }
 970
 971         session->tracing_id = tracing_id;
 972         session->tracing_uid = tracing_uid;
 973
 974         pthread_mutex_lock(&session->lock);
 975         ret = ust_metadata_session_statedump(session, app, major, minor);
 976         pthread_mutex_unlock(&session->lock);
 977         if (ret) {
 978                 ERR("Failed to generate session metadata (errno = %d)", ret);
 979                 goto error;
 980         }
 981
 982         *sessionp = session;
 983
 984         return 0;
 985
 986 error:
 987         ust_registry_session_destroy(session);
 988         free(session);
 989 error_alloc:
 990         return -1;
 991 }
 992
 993 /*
 994  * Destroy session registry. This does NOT free the given pointer since it
 995  * might get passed as a reference. The registry lock should NOT be acquired.
 996  */
 997 void ust_registry_session_destroy(struct ust_registry_session *reg)
 998 {
 999         int ret;
1000         struct lttng_ht_iter iter;
1001         struct ust_registry_channel *chan;
1002         struct ust_registry_enum *reg_enum;
1003
1004         if (!reg) {
1005                 return;
1006         }
1007
1008         /* On error, EBUSY can be returned if lock. Code flow error. */
1009         ret = pthread_mutex_destroy(&reg->lock);
1010         assert(!ret);
1011
1012         if (reg->channels) {
1013                 rcu_read_lock();
1014                 /* Destroy all event associated with this registry. */
1015                 cds_lfht_for_each_entry(reg->channels->ht, &iter.iter, chan,
1016                                 node.node) {
1017                         /* Delete the node from the ht and free it. */
1018                         ret = lttng_ht_del(reg->channels, &iter);
1019                         assert(!ret);
1020                         destroy_channel(chan, true);
1021                 }
1022                 rcu_read_unlock();
1023                 ht_cleanup_push(reg->channels);
1024         }
1025
1026         free(reg->metadata);
1027         if (reg->metadata_fd >= 0) {
1028                 ret = close(reg->metadata_fd);
1029                 if (ret) {
1030                         PERROR("close");
1031                 }
1032                 ret = run_as_unlink(reg->metadata_path,
1033                                 reg->uid, reg->gid);
1034                 if (ret) {
1035                         PERROR("unlink");
1036                 }
1037         }
1038         if (reg->root_shm_path[0]) {
1039                 /*
1040                  * Try deleting the directory hierarchy.
1041                  */
1042                 (void) run_as_rmdir_recursive(reg->root_shm_path,
1043                                 reg->uid, reg->gid,
1044                                 LTTNG_DIRECTORY_HANDLE_SKIP_NON_EMPTY_FLAG);
1045         }
1046         /* Destroy the enum hash table */
1047         if (reg->enums) {
1048                 rcu_read_lock();
1049                 /* Destroy all enum entries associated with this registry. */
1050                 cds_lfht_for_each_entry(reg->enums->ht, &iter.iter, reg_enum,
1051                                 node.node) {
1052                         ust_registry_destroy_enum(reg, reg_enum);
1053                 }
1054                 rcu_read_unlock();
1055                 ht_cleanup_push(reg->enums);
1056         }
1057 }