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