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

   1 /*
   2  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #define _LGPL_SOURCE
  19 #include <assert.h>
  20 #include <inttypes.h>
  21
  22 #include <common/common.h>
  23 #include <common/hashtable/utils.h>
  24 #include <lttng/lttng.h>
  25
  26 #include "ust-registry.h"
  27 #include "ust-app.h"
  28 #include "ust-field-utils.h"
  29 #include "utils.h"
  30
  31
  32 /*
  33  * Hash table match function for event in the registry.
  34  */
  35 static int ht_match_event(struct cds_lfht_node *node, const void *_key)
  36 {
  37         const struct ust_registry_event *key;
  38         struct ust_registry_event *event;
  39         int i;
  40
  41         assert(node);
  42         assert(_key);
  43
  44         event = caa_container_of(node, struct ust_registry_event, node.node);
  45         assert(event);
  46         key = _key;
  47
  48         /* It has to be a perfect match. First, compare the event names. */
  49         if (strncmp(event->name, key->name, sizeof(event->name))) {
  50                 goto no_match;
  51         }
  52
  53         /* Compare log levels. */
  54         if (event->loglevel_value != key->loglevel_value) {
  55                 goto no_match;
  56         }
  57
  58         /* Compare the number of fields. */
  59         if (event->nr_fields != key->nr_fields) {
  60                 goto no_match;
  61         }
  62
  63         /* Compare each field individually. */
  64         for (i = 0; i < event->nr_fields; i++) {
  65                 if (!match_ustctl_field(&event->fields[i], &key->fields[i])) {
  66                         goto no_match;
  67                 }
  68         }
  69
  70         /* Compare model URI. */
  71         if (event->model_emf_uri != NULL && key->model_emf_uri == NULL) {
  72                 goto no_match;
  73         } else if(event->model_emf_uri == NULL && key->model_emf_uri != NULL) {
  74                 goto no_match;
  75         } else if (event->model_emf_uri != NULL && key->model_emf_uri != NULL) {
  76                 if (strcmp(event->model_emf_uri, key->model_emf_uri)) {
  77                         goto no_match;
  78                 }
  79         }
  80
  81         /* Match */
  82         return 1;
  83
  84 no_match:
  85         return 0;
  86 }
  87
  88 static unsigned long ht_hash_event(void *_key, unsigned long seed)
  89 {
  90         uint64_t hashed_key;
  91         struct ust_registry_event *key = _key;
  92
  93         assert(key);
  94
  95         hashed_key = (uint64_t) hash_key_str(key->name, seed);
  96
  97         return hash_key_u64(&hashed_key, seed);
  98 }
  99
 100 static int compare_enums(const struct ust_registry_enum *reg_enum_a,
 101                 const struct ust_registry_enum *reg_enum_b)
 102 {
 103         int ret = 0;
 104         size_t i;
 105
 106         assert(strcmp(reg_enum_a->name, reg_enum_b->name) == 0);
 107         if (reg_enum_a->nr_entries != reg_enum_b->nr_entries) {
 108                 ret = -1;
 109                 goto end;
 110         }
 111         for (i = 0; i < reg_enum_a->nr_entries; i++) {
 112                 const struct ustctl_enum_entry *entries_a, *entries_b;
 113
 114                 entries_a = &reg_enum_a->entries[i];
 115                 entries_b = &reg_enum_b->entries[i];
 116                 if (entries_a->start.value != entries_b->start.value) {
 117                         ret = -1;
 118                         goto end;
 119                 }
 120                 if (entries_a->end.value != entries_b->end.value) {
 121                         ret = -1;
 122                         goto end;
 123                 }
 124                 if (entries_a->start.signedness != entries_b->start.signedness) {
 125                         ret = -1;
 126                         goto end;
 127                 }
 128                 if (entries_a->end.signedness != entries_b->end.signedness) {
 129                         ret = -1;
 130                         goto end;
 131                 }
 132
 133                 if (strcmp(entries_a->string, entries_b->string)) {
 134                         ret = -1;
 135                         goto end;
 136                 }
 137         }
 138 end:
 139         return ret;
 140 }
 141
 142 /*
 143  * Hash table match function for enumerations in the session. Match is
 144  * performed on enumeration name, and confirmed by comparing the enum
 145  * entries.
 146  */
 147 static int ht_match_enum(struct cds_lfht_node *node, const void *_key)
 148 {
 149         struct ust_registry_enum *_enum;
 150         const struct ust_registry_enum *key;
 151
 152         assert(node);
 153         assert(_key);
 154
 155         _enum = caa_container_of(node, struct ust_registry_enum,
 156                         node.node);
 157         assert(_enum);
 158         key = _key;
 159
 160         if (strncmp(_enum->name, key->name, LTTNG_UST_SYM_NAME_LEN)) {
 161                 goto no_match;
 162         }
 163         if (compare_enums(_enum, key)) {
 164                 goto no_match;
 165         }
 166
 167         /* Match. */
 168         return 1;
 169
 170 no_match:
 171         return 0;
 172 }
 173
 174 /*
 175  * Hash table match function for enumerations in the session. Match is
 176  * performed by enumeration ID.
 177  */
 178 static int ht_match_enum_id(struct cds_lfht_node *node, const void *_key)
 179 {
 180         struct ust_registry_enum *_enum;
 181         const struct ust_registry_enum *key = _key;
 182
 183         assert(node);
 184         assert(_key);
 185
 186         _enum = caa_container_of(node, struct ust_registry_enum, node.node);
 187         assert(_enum);
 188
 189         if (_enum->id != key->id) {
 190                 goto no_match;
 191         }
 192
 193         /* Match. */
 194         return 1;
 195
 196 no_match:
 197         return 0;
 198 }
 199
 200 /*
 201  * Hash table hash function for enumerations in the session. The
 202  * enumeration name is used for hashing.
 203  */
 204 static unsigned long ht_hash_enum(void *_key, unsigned long seed)
 205 {
 206         struct ust_registry_enum *key = _key;
 207
 208         assert(key);
 209         return hash_key_str(key->name, seed);
 210 }
 211
 212 /*
 213  * Return negative value on error, 0 if OK.
 214  *
 215  * TODO: we could add stricter verification of more types to catch
 216  * errors in liblttng-ust implementation earlier than consumption by the
 217  * trace reader.
 218  */
 219 static
 220 int validate_event_field(struct ustctl_field *field,
 221                 const char *event_name,
 222                 struct ust_app *app)
 223 {
 224         int ret = 0;
 225
 226         switch(field->type.atype) {
 227         case ustctl_atype_integer:
 228         case ustctl_atype_enum:
 229         case ustctl_atype_array:
 230         case ustctl_atype_sequence:
 231         case ustctl_atype_string:
 232         case ustctl_atype_variant:
 233                 break;
 234         case ustctl_atype_struct:
 235                 if (field->type.u._struct.nr_fields != 0) {
 236                         WARN("Unsupported non-empty struct field.");
 237                         ret = -EINVAL;
 238                         goto end;
 239                 }
 240                 break;
 241
 242         case ustctl_atype_float:
 243                 switch (field->type.u.basic._float.mant_dig) {
 244                 case 0:
 245                         WARN("UST application '%s' (pid: %d) has unknown float mantissa '%u' "
 246                                 "in field '%s', rejecting event '%s'",
 247                                 app->name, app->pid,
 248                                 field->type.u.basic._float.mant_dig,
 249                                 field->name,
 250                                 event_name);
 251                         ret = -EINVAL;
 252                         goto end;
 253                 default:
 254                         break;
 255                 }
 256                 break;
 257
 258         default:
 259                 ret = -ENOENT;
 260                 goto end;
 261         }
 262 end:
 263         return ret;
 264 }
 265
 266 static
 267 int validate_event_fields(size_t nr_fields, struct ustctl_field *fields,
 268                 const char *event_name, struct ust_app *app)
 269 {
 270         unsigned int i;
 271
 272         for (i = 0; i < nr_fields; i++) {
 273                 if (validate_event_field(&fields[i], event_name, app) < 0)
 274                         return -EINVAL;
 275         }
 276         return 0;
 277 }
 278
 279 /*
 280  * Allocate event and initialize it. This does NOT set a valid event id from a
 281  * registry.
 282  */
 283 static struct ust_registry_event *alloc_event(int session_objd,
 284                 int channel_objd, char *name, char *sig, size_t nr_fields,
 285                 struct ustctl_field *fields, int loglevel_value,
 286                 char *model_emf_uri, struct ust_app *app)
 287 {
 288         struct ust_registry_event *event = NULL;
 289
 290         /*
 291          * Ensure that the field content is valid.
 292          */
 293         if (validate_event_fields(nr_fields, fields, name, app) < 0) {
 294                 return NULL;
 295         }
 296
 297         event = zmalloc(sizeof(*event));
 298         if (!event) {
 299                 PERROR("zmalloc ust registry event");
 300                 goto error;
 301         }
 302
 303         event->session_objd = session_objd;
 304         event->channel_objd = channel_objd;
 305         /* Allocated by ustctl. */
 306         event->signature = sig;
 307         event->nr_fields = nr_fields;
 308         event->fields = fields;
 309         event->loglevel_value = loglevel_value;
 310         event->model_emf_uri = model_emf_uri;
 311         if (name) {
 312                 /* Copy event name and force NULL byte. */
 313                 strncpy(event->name, name, sizeof(event->name));
 314                 event->name[sizeof(event->name) - 1] = '\0';
 315         }
 316         cds_lfht_node_init(&event->node.node);
 317
 318 error:
 319         return event;
 320 }
 321
 322 /*
 323  * Free event data structure. This does NOT delete it from any hash table. It's
 324  * safe to pass a NULL pointer. This shoudl be called inside a call RCU if the
 325  * event is previously deleted from a rcu hash table.
 326  */
 327 static void destroy_event(struct ust_registry_event *event)
 328 {
 329         if (!event) {
 330                 return;
 331         }
 332
 333         free(event->fields);
 334         free(event->model_emf_uri);
 335         free(event->signature);
 336         free(event);
 337 }
 338
 339 /*
 340  * Destroy event function call of the call RCU.
 341  */
 342 static void destroy_event_rcu(struct rcu_head *head)
 343 {
 344         struct lttng_ht_node_u64 *node =
 345                 caa_container_of(head, struct lttng_ht_node_u64, head);
 346         struct ust_registry_event *event =
 347                 caa_container_of(node, struct ust_registry_event, node);
 348
 349         destroy_event(event);
 350 }
 351
 352 /*
 353  * Find an event using the name and signature in the given registry. RCU read
 354  * side lock MUST be acquired before calling this function and as long as the
 355  * event reference is kept by the caller.
 356  *
 357  * On success, the event pointer is returned else NULL.
 358  */
 359 struct ust_registry_event *ust_registry_find_event(
 360                 struct ust_registry_channel *chan, char *name, char *sig)
 361 {
 362         struct lttng_ht_node_u64 *node;
 363         struct lttng_ht_iter iter;
 364         struct ust_registry_event *event = NULL;
 365         struct ust_registry_event key;
 366
 367         assert(chan);
 368         assert(name);
 369         assert(sig);
 370
 371         /* Setup key for the match function. */
 372         strncpy(key.name, name, sizeof(key.name));
 373         key.name[sizeof(key.name) - 1] = '\0';
 374         key.signature = sig;
 375
 376         cds_lfht_lookup(chan->ht->ht, chan->ht->hash_fct(&key, lttng_ht_seed),
 377                         chan->ht->match_fct, &key, &iter.iter);
 378         node = lttng_ht_iter_get_node_u64(&iter);
 379         if (!node) {
 380                 goto end;
 381         }
 382         event = caa_container_of(node, struct ust_registry_event, node);
 383
 384 end:
 385         return event;
 386 }
 387
 388 /*
 389  * Create a ust_registry_event from the given parameters and add it to the
 390  * registry hash table. If event_id is valid, it is set with the newly created
 391  * event id.
 392  *
 393  * On success, return 0 else a negative value. The created event MUST be unique
 394  * so on duplicate entry -EINVAL is returned. On error, event_id is untouched.
 395  *
 396  * Should be called with session registry mutex held.
 397  */
 398 int ust_registry_create_event(struct ust_registry_session *session,
 399                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 400                 char *sig, size_t nr_fields, struct ustctl_field *fields,
 401                 int loglevel_value, char *model_emf_uri, int buffer_type,
 402                 uint32_t *event_id_p, struct ust_app *app)
 403 {
 404         int ret;
 405         uint32_t event_id;
 406         struct cds_lfht_node *nptr;
 407         struct ust_registry_event *event = NULL;
 408         struct ust_registry_channel *chan;
 409
 410         assert(session);
 411         assert(name);
 412         assert(sig);
 413         assert(event_id_p);
 414
 415         rcu_read_lock();
 416
 417         /*
 418          * This should not happen but since it comes from the UST tracer, an
 419          * external party, don't assert and simply validate values.
 420          */
 421         if (session_objd < 0 || channel_objd < 0) {
 422                 ret = -EINVAL;
 423                 goto error_free;
 424         }
 425
 426         chan = ust_registry_channel_find(session, chan_key);
 427         if (!chan) {
 428                 ret = -EINVAL;
 429                 goto error_free;
 430         }
 431
 432         /* Check if we've reached the maximum possible id. */
 433         if (ust_registry_is_max_id(chan->used_event_id)) {
 434                 ret = -ENOENT;
 435                 goto error_free;
 436         }
 437
 438         event = alloc_event(session_objd, channel_objd, name, sig, nr_fields,
 439                         fields, loglevel_value, model_emf_uri, app);
 440         if (!event) {
 441                 ret = -ENOMEM;
 442                 goto error_free;
 443         }
 444
 445         DBG3("UST registry creating event with event: %s, sig: %s, id: %u, "
 446                         "chan_objd: %u, sess_objd: %u, chan_id: %u", event->name,
 447                         event->signature, event->id, event->channel_objd,
 448                         event->session_objd, chan->chan_id);
 449
 450         /*
 451          * This is an add unique with a custom match function for event. The node
 452          * are matched using the event name and signature.
 453          */
 454         nptr = cds_lfht_add_unique(chan->ht->ht, chan->ht->hash_fct(event,
 455                                 lttng_ht_seed), chan->ht->match_fct, event, &event->node.node);
 456         if (nptr != &event->node.node) {
 457                 if (buffer_type == LTTNG_BUFFER_PER_UID) {
 458                         /*
 459                          * This is normal, we just have to send the event id of the
 460                          * returned node and make sure we destroy the previously allocated
 461                          * event object.
 462                          */
 463                         destroy_event(event);
 464                         event = caa_container_of(nptr, struct ust_registry_event,
 465                                         node.node);
 466                         assert(event);
 467                         event_id = event->id;
 468                 } else {
 469                         ERR("UST registry create event add unique failed for event: %s, "
 470                                         "sig: %s, id: %u, chan_objd: %u, sess_objd: %u",
 471                                         event->name, event->signature, event->id,
 472                                         event->channel_objd, event->session_objd);
 473                         ret = -EINVAL;
 474                         goto error_unlock;
 475                 }
 476         } else {
 477                 /* Request next event id if the node was successfully added. */
 478                 event_id = event->id = ust_registry_get_next_event_id(chan);
 479         }
 480
 481         *event_id_p = event_id;
 482
 483         if (!event->metadata_dumped) {
 484                 /* Append to metadata */
 485                 ret = ust_metadata_event_statedump(session, chan, event);
 486                 if (ret) {
 487                         ERR("Error appending event metadata (errno = %d)", ret);
 488                         rcu_read_unlock();
 489                         return ret;
 490                 }
 491         }
 492
 493         rcu_read_unlock();
 494         return 0;
 495
 496 error_free:
 497         free(sig);
 498         free(fields);
 499         free(model_emf_uri);
 500 error_unlock:
 501         rcu_read_unlock();
 502         destroy_event(event);
 503         return ret;
 504 }
 505
 506 /*
 507  * For a given event in a registry, delete the entry and destroy the event.
 508  * This MUST be called within a RCU read side lock section.
 509  */
 510 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 511                 struct ust_registry_event *event)
 512 {
 513         int ret;
 514         struct lttng_ht_iter iter;
 515
 516         assert(chan);
 517         assert(event);
 518
 519         /* Delete the node first. */
 520         iter.iter.node = &event->node.node;
 521         ret = lttng_ht_del(chan->ht, &iter);
 522         assert(!ret);
 523
 524         call_rcu(&event->node.head, destroy_event_rcu);
 525
 526         return;
 527 }
 528
 529 static void destroy_enum(struct ust_registry_enum *reg_enum)
 530 {
 531         if (!reg_enum) {
 532                 return;
 533         }
 534         free(reg_enum->entries);
 535         free(reg_enum);
 536 }
 537
 538 static void destroy_enum_rcu(struct rcu_head *head)
 539 {
 540         struct ust_registry_enum *reg_enum =
 541                 caa_container_of(head, struct ust_registry_enum, rcu_head);
 542
 543         destroy_enum(reg_enum);
 544 }
 545
 546 /*
 547  * Lookup enumeration by name and comparing enumeration entries.
 548  * Needs to be called from RCU read-side critical section.
 549  */
 550 struct ust_registry_enum *
 551         ust_registry_lookup_enum(struct ust_registry_session *session,
 552                 const struct ust_registry_enum *reg_enum_lookup)
 553 {
 554         struct ust_registry_enum *reg_enum = NULL;
 555         struct lttng_ht_node_str *node;
 556         struct lttng_ht_iter iter;
 557
 558         cds_lfht_lookup(session->enums->ht,
 559                         ht_hash_enum((void *) reg_enum_lookup, lttng_ht_seed),
 560                         ht_match_enum, reg_enum_lookup, &iter.iter);
 561         node = lttng_ht_iter_get_node_str(&iter);
 562         if (!node) {
 563                 goto end;
 564         }
 565         reg_enum = caa_container_of(node, struct ust_registry_enum, node);
 566 end:
 567         return reg_enum;
 568 }
 569
 570 /*
 571  * Lookup enumeration by enum ID.
 572  * Needs to be called from RCU read-side critical section.
 573  */
 574 struct ust_registry_enum *
 575         ust_registry_lookup_enum_by_id(struct ust_registry_session *session,
 576                 const char *enum_name, uint64_t enum_id)
 577 {
 578         struct ust_registry_enum *reg_enum = NULL;
 579         struct lttng_ht_node_str *node;
 580         struct lttng_ht_iter iter;
 581         struct ust_registry_enum reg_enum_lookup;
 582
 583         memset(&reg_enum_lookup, 0, sizeof(reg_enum_lookup));
 584         strncpy(reg_enum_lookup.name, enum_name, LTTNG_UST_SYM_NAME_LEN);
 585         reg_enum_lookup.name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 586         reg_enum_lookup.id = enum_id;
 587         cds_lfht_lookup(session->enums->ht,
 588                         ht_hash_enum((void *) &reg_enum_lookup, lttng_ht_seed),
 589                         ht_match_enum_id, &reg_enum_lookup, &iter.iter);
 590         node = lttng_ht_iter_get_node_str(&iter);
 591         if (!node) {
 592                 goto end;
 593         }
 594         reg_enum = caa_container_of(node, struct ust_registry_enum, node);
 595 end:
 596         return reg_enum;
 597 }
 598
 599 /*
 600  * Create a ust_registry_enum from the given parameters and add it to the
 601  * registry hash table, or find it if already there.
 602  *
 603  * On success, return 0 else a negative value.
 604  *
 605  * Should be called with session registry mutex held.
 606  *
 607  * We receive ownership of entries.
 608  */
 609 int ust_registry_create_or_find_enum(struct ust_registry_session *session,
 610                 int session_objd, char *enum_name,
 611                 struct ustctl_enum_entry *entries, size_t nr_entries,
 612                 uint64_t *enum_id)
 613 {
 614         int ret = 0;
 615         struct cds_lfht_node *nodep;
 616         struct ust_registry_enum *reg_enum = NULL, *old_reg_enum;
 617
 618         assert(session);
 619         assert(enum_name);
 620
 621         rcu_read_lock();
 622
 623         /*
 624          * This should not happen but since it comes from the UST tracer, an
 625          * external party, don't assert and simply validate values.
 626          */
 627         if (session_objd < 0) {
 628                 ret = -EINVAL;
 629                 goto end;
 630         }
 631
 632         /* Check if the enumeration was already dumped */
 633         reg_enum = zmalloc(sizeof(*reg_enum));
 634         if (!reg_enum) {
 635                 PERROR("zmalloc ust registry enumeration");
 636                 ret = -ENOMEM;
 637                 goto end;
 638         }
 639         strncpy(reg_enum->name, enum_name, LTTNG_UST_SYM_NAME_LEN);
 640         reg_enum->name[LTTNG_UST_SYM_NAME_LEN - 1] = '\0';
 641         /* entries will be owned by reg_enum. */
 642         reg_enum->entries = entries;
 643         reg_enum->nr_entries = nr_entries;
 644         entries = NULL;
 645
 646         old_reg_enum = ust_registry_lookup_enum(session, reg_enum);
 647         if (old_reg_enum) {
 648                 DBG("enum %s already in sess_objd: %u", enum_name, session_objd);
 649                 /* Fall through. Use prior enum. */
 650                 destroy_enum(reg_enum);
 651                 reg_enum = old_reg_enum;
 652         } else {
 653                 DBG("UST registry creating enum: %s, sess_objd: %u",
 654                                 enum_name, session_objd);
 655                 if (session->next_enum_id == -1ULL) {
 656                         ret = -EOVERFLOW;
 657                         destroy_enum(reg_enum);
 658                         goto end;
 659                 }
 660                 reg_enum->id = session->next_enum_id++;
 661                 cds_lfht_node_init(&reg_enum->node.node);
 662                 nodep = cds_lfht_add_unique(session->enums->ht,
 663                                 ht_hash_enum(reg_enum, lttng_ht_seed),
 664                                 ht_match_enum_id, reg_enum,
 665                                 &reg_enum->node.node);
 666                 assert(nodep == &reg_enum->node.node);
 667         }
 668         DBG("UST registry reply with enum %s with id %" PRIu64 " in sess_objd: %u",
 669                         enum_name, reg_enum->id, session_objd);
 670         *enum_id = reg_enum->id;
 671 end:
 672         free(entries);
 673         rcu_read_unlock();
 674         return ret;
 675 }
 676
 677 /*
 678  * For a given enumeration in a registry, delete the entry and destroy
 679  * the enumeration.
 680  * This MUST be called within a RCU read side lock section.
 681  */
 682 void ust_registry_destroy_enum(struct ust_registry_session *reg_session,
 683                 struct ust_registry_enum *reg_enum)
 684 {
 685         int ret;
 686         struct lttng_ht_iter iter;
 687
 688         assert(reg_session);
 689         assert(reg_enum);
 690
 691         /* Delete the node first. */
 692         iter.iter.node = &reg_enum->node.node;
 693         ret = lttng_ht_del(reg_session->enums, &iter);
 694         assert(!ret);
 695         call_rcu(&reg_enum->rcu_head, destroy_enum_rcu);
 696 }
 697
 698 /*
 699  * We need to execute ht_destroy outside of RCU read-side critical
 700  * section and outside of call_rcu thread, so we postpone its execution
 701  * using ht_cleanup_push. It is simpler than to change the semantic of
 702  * the many callers of delete_ust_app_session().
 703  */
 704 static
 705 void destroy_channel_rcu(struct rcu_head *head)
 706 {
 707         struct ust_registry_channel *chan =
 708                 caa_container_of(head, struct ust_registry_channel, rcu_head);
 709
 710         if (chan->ht) {
 711                 ht_cleanup_push(chan->ht);
 712         }
 713         free(chan->ctx_fields);
 714         free(chan);
 715 }
 716
 717 /*
 718  * Destroy every element of the registry and free the memory. This does NOT
 719  * free the registry pointer since it might not have been allocated before so
 720  * it's the caller responsability.
 721  */
 722 static void destroy_channel(struct ust_registry_channel *chan)
 723 {
 724         struct lttng_ht_iter iter;
 725         struct ust_registry_event *event;
 726
 727         assert(chan);
 728
 729         rcu_read_lock();
 730         /* Destroy all event associated with this registry. */
 731         cds_lfht_for_each_entry(chan->ht->ht, &iter.iter, event, node.node) {
 732                 /* Delete the node from the ht and free it. */
 733                 ust_registry_destroy_event(chan, event);
 734         }
 735         rcu_read_unlock();
 736         call_rcu(&chan->rcu_head, destroy_channel_rcu);
 737 }
 738
 739 /*
 740  * Initialize registry with default values.
 741  */
 742 int ust_registry_channel_add(struct ust_registry_session *session,
 743                 uint64_t key)
 744 {
 745         int ret = 0;
 746         struct ust_registry_channel *chan;
 747
 748         assert(session);
 749
 750         chan = zmalloc(sizeof(*chan));
 751         if (!chan) {
 752                 PERROR("zmalloc ust registry channel");
 753                 ret = -ENOMEM;
 754                 goto error_alloc;
 755         }
 756
 757         chan->ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 758         if (!chan->ht) {
 759                 ret = -ENOMEM;
 760                 goto error;
 761         }
 762
 763         /* Set custom match function. */
 764         chan->ht->match_fct = ht_match_event;
 765         chan->ht->hash_fct = ht_hash_event;
 766
 767         /*
 768          * Assign a channel ID right now since the event notification comes
 769          * *before* the channel notify so the ID needs to be set at this point so
 770          * the metadata can be dumped for that event.
 771          */
 772         if (ust_registry_is_max_id(session->used_channel_id)) {
 773                 ret = -1;
 774                 goto error;
 775         }
 776         chan->chan_id = ust_registry_get_next_chan_id(session);
 777
 778         rcu_read_lock();
 779         lttng_ht_node_init_u64(&chan->node, key);
 780         lttng_ht_add_unique_u64(session->channels, &chan->node);
 781         rcu_read_unlock();
 782
 783         return 0;
 784
 785 error:
 786         destroy_channel(chan);
 787 error_alloc:
 788         return ret;
 789 }
 790
 791 /*
 792  * Find a channel in the given registry. RCU read side lock MUST be acquired
 793  * before calling this function and as long as the event reference is kept by
 794  * the caller.
 795  *
 796  * On success, the pointer is returned else NULL.
 797  */
 798 struct ust_registry_channel *ust_registry_channel_find(
 799                 struct ust_registry_session *session, uint64_t key)
 800 {
 801         struct lttng_ht_node_u64 *node;
 802         struct lttng_ht_iter iter;
 803         struct ust_registry_channel *chan = NULL;
 804
 805         assert(session);
 806         assert(session->channels);
 807
 808         DBG3("UST registry channel finding key %" PRIu64, key);
 809
 810         lttng_ht_lookup(session->channels, &key, &iter);
 811         node = lttng_ht_iter_get_node_u64(&iter);
 812         if (!node) {
 813                 goto end;
 814         }
 815         chan = caa_container_of(node, struct ust_registry_channel, node);
 816
 817 end:
 818         return chan;
 819 }
 820
 821 /*
 822  * Remove channel using key from registry and free memory.
 823  */
 824 void ust_registry_channel_del_free(struct ust_registry_session *session,
 825                 uint64_t key)
 826 {
 827         struct lttng_ht_iter iter;
 828         struct ust_registry_channel *chan;
 829         int ret;
 830
 831         assert(session);
 832
 833         rcu_read_lock();
 834         chan = ust_registry_channel_find(session, key);
 835         if (!chan) {
 836                 rcu_read_unlock();
 837                 goto end;
 838         }
 839
 840         iter.iter.node = &chan->node.node;
 841         ret = lttng_ht_del(session->channels, &iter);
 842         assert(!ret);
 843         rcu_read_unlock();
 844         destroy_channel(chan);
 845
 846 end:
 847         return;
 848 }
 849
 850 /*
 851  * Initialize registry with default values and set the newly allocated session
 852  * pointer to sessionp.
 853  *
 854  * Return 0 on success and sessionp is set or else return -1 and sessionp is
 855  * kept untouched.
 856  */
 857 int ust_registry_session_init(struct ust_registry_session **sessionp,
 858                 struct ust_app *app,
 859                 uint32_t bits_per_long,
 860                 uint32_t uint8_t_alignment,
 861                 uint32_t uint16_t_alignment,
 862                 uint32_t uint32_t_alignment,
 863                 uint32_t uint64_t_alignment,
 864                 uint32_t long_alignment,
 865                 int byte_order,
 866                 uint32_t major,
 867                 uint32_t minor,
 868                 const char *root_shm_path,
 869                 const char *shm_path,
 870                 uid_t euid,
 871                 gid_t egid)
 872 {
 873         int ret;
 874         struct ust_registry_session *session;
 875
 876         assert(sessionp);
 877
 878         session = zmalloc(sizeof(*session));
 879         if (!session) {
 880                 PERROR("zmalloc ust registry session");
 881                 goto error_alloc;
 882         }
 883
 884         pthread_mutex_init(&session->lock, NULL);
 885         session->bits_per_long = bits_per_long;
 886         session->uint8_t_alignment = uint8_t_alignment;
 887         session->uint16_t_alignment = uint16_t_alignment;
 888         session->uint32_t_alignment = uint32_t_alignment;
 889         session->uint64_t_alignment = uint64_t_alignment;
 890         session->long_alignment = long_alignment;
 891         session->byte_order = byte_order;
 892         session->metadata_fd = -1;
 893         session->uid = euid;
 894         session->gid = egid;
 895         session->next_enum_id = 0;
 896         session->major = major;
 897         session->minor = minor;
 898         strncpy(session->root_shm_path, root_shm_path,
 899                 sizeof(session->root_shm_path));
 900         session->root_shm_path[sizeof(session->root_shm_path) - 1] = '\0';
 901         if (shm_path[0]) {
 902                 strncpy(session->shm_path, shm_path,
 903                         sizeof(session->shm_path));
 904                 session->shm_path[sizeof(session->shm_path) - 1] = '\0';
 905                 strncpy(session->metadata_path, shm_path,
 906                         sizeof(session->metadata_path));
 907                 session->metadata_path[sizeof(session->metadata_path) - 1] = '\0';
 908                 strncat(session->metadata_path, "/metadata",
 909                         sizeof(session->metadata_path)
 910                                 - strlen(session->metadata_path) - 1);
 911         }
 912         if (session->shm_path[0]) {
 913                 ret = run_as_mkdir_recursive(session->shm_path,
 914                         S_IRWXU | S_IRWXG,
 915                         euid, egid);
 916                 if (ret) {
 917                         PERROR("run_as_mkdir_recursive");
 918                         goto error;
 919                 }
 920         }
 921         if (session->metadata_path[0]) {
 922                 /* Create metadata file */
 923                 ret = run_as_open(session->metadata_path,
 924                         O_WRONLY | O_CREAT | O_EXCL,
 925                         S_IRUSR | S_IWUSR, euid, egid);
 926                 if (ret < 0) {
 927                         PERROR("Opening metadata file");
 928                         goto error;
 929                 }
 930                 session->metadata_fd = ret;
 931         }
 932
 933         session->enums = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 934         if (!session->enums) {
 935                 ret = -ENOMEM;
 936                 goto error;
 937         }
 938         /* hash/match functions are specified at call site. */
 939         session->enums->match_fct = NULL;
 940         session->enums->hash_fct = NULL;
 941
 942         session->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 943         if (!session->channels) {
 944                 goto error;
 945         }
 946
 947         ret = lttng_uuid_generate(session->uuid);
 948         if (ret) {
 949                 ERR("Failed to generate UST uuid (errno = %d)", ret);
 950                 goto error;
 951         }
 952
 953         pthread_mutex_lock(&session->lock);
 954         ret = ust_metadata_session_statedump(session, app, major, minor);
 955         pthread_mutex_unlock(&session->lock);
 956         if (ret) {
 957                 ERR("Failed to generate session metadata (errno = %d)", ret);
 958                 goto error;
 959         }
 960
 961         *sessionp = session;
 962
 963         return 0;
 964
 965 error:
 966         ust_registry_session_destroy(session);
 967         free(session);
 968 error_alloc:
 969         return -1;
 970 }
 971
 972 /*
 973  * Destroy session registry. This does NOT free the given pointer since it
 974  * might get passed as a reference. The registry lock should NOT be acquired.
 975  */
 976 void ust_registry_session_destroy(struct ust_registry_session *reg)
 977 {
 978         int ret;
 979         struct lttng_ht_iter iter;
 980         struct ust_registry_channel *chan;
 981         struct ust_registry_enum *reg_enum;
 982
 983         if (!reg) {
 984                 return;
 985         }
 986
 987         /* On error, EBUSY can be returned if lock. Code flow error. */
 988         ret = pthread_mutex_destroy(&reg->lock);
 989         assert(!ret);
 990
 991         if (reg->channels) {
 992                 rcu_read_lock();
 993                 /* Destroy all event associated with this registry. */
 994                 cds_lfht_for_each_entry(reg->channels->ht, &iter.iter, chan,
 995                                 node.node) {
 996                         /* Delete the node from the ht and free it. */
 997                         ret = lttng_ht_del(reg->channels, &iter);
 998                         assert(!ret);
 999                         destroy_channel(chan);
1000                 }
1001                 rcu_read_unlock();
1002                 ht_cleanup_push(reg->channels);
1003         }
1004
1005         free(reg->metadata);
1006         if (reg->metadata_fd >= 0) {
1007                 ret = close(reg->metadata_fd);
1008                 if (ret) {
1009                         PERROR("close");
1010                 }
1011                 ret = run_as_unlink(reg->metadata_path,
1012                                 reg->uid, reg->gid);
1013                 if (ret) {
1014                         PERROR("unlink");
1015                 }
1016         }
1017         if (reg->root_shm_path[0]) {
1018                 /*
1019                  * Try deleting the directory hierarchy.
1020                  */
1021                 (void) run_as_recursive_rmdir(reg->root_shm_path,
1022                                 reg->uid, reg->gid);
1023         }
1024         /* Destroy the enum hash table */
1025         if (reg->enums) {
1026                 rcu_read_lock();
1027                 /* Destroy all enum entries associated with this registry. */
1028                 cds_lfht_for_each_entry(reg->enums->ht, &iter.iter, reg_enum,
1029                                 node.node) {
1030                         ust_registry_destroy_enum(reg, reg_enum);
1031                 }
1032                 rcu_read_unlock();
1033                 ht_cleanup_push(reg->enums);
1034         }
1035 }