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