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

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