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