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 #include "lttng-sessiond.h"
  31 #include "notification-thread-commands.h"
  32
  33
  34 /*
  35  * Hash table match function for event in the registry.
  36  */
  37 static int ht_match_event(struct cds_lfht_node *node, const void *_key)
  38 {
  39         const struct ust_registry_event *key;
  40         struct ust_registry_event *event;
  41         int i;
  42
  43         assert(node);
  44         assert(_key);
  45
  46         event = caa_container_of(node, struct ust_registry_event, node.node);
  47         assert(event);
  48         key = _key;
  49
  50         /* It has to be a perfect match. First, compare the event names. */
  51         if (strncmp(event->name, key->name, sizeof(event->name))) {
  52                 goto no_match;
  53         }
  54
  55         /* Compare log levels. */
  56         if (event->loglevel_value != key->loglevel_value) {
  57                 goto no_match;
  58         }
  59
  60         /* Compare the number of fields. */
  61         if (event->nr_fields != key->nr_fields) {
  62                 goto no_match;
  63         }
  64
  65         /* Compare each field individually. */
  66         for (i = 0; i < event->nr_fields; i++) {
  67                 if (!match_ustctl_field(&event->fields[i], &key->fields[i])) {
  68                         goto no_match;
  69                 }
  70         }
  71
  72         /* Compare model URI. */
  73         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                 goto no_match;
  77         } else if (event->model_emf_uri != NULL && key->model_emf_uri != NULL) {
  78                 if (strcmp(event->model_emf_uri, key->model_emf_uri)) {
  79                         goto no_match;
  80                 }
  81         }
  82
  83         /* Match */
  84         return 1;
  85
  86 no_match:
  87         return 0;
  88 }
  89
  90 static unsigned long ht_hash_event(const void *_key, unsigned long seed)
  91 {
  92         uint64_t hashed_key;
  93         const struct ust_registry_event *key = _key;
  94
  95         assert(key);
  96
  97         hashed_key = (uint64_t) hash_key_str(key->name, seed);
  98
  99         return hash_key_u64(&hashed_key, seed);
 100 }
 101
 102 static int compare_enums(const struct ust_registry_enum *reg_enum_a,
 103                 const struct ust_registry_enum *reg_enum_b)
 104 {
 105         int ret = 0;
 106         size_t i;
 107
 108         assert(strcmp(reg_enum_a->name, reg_enum_b->name) == 0);
 109         if (reg_enum_a->nr_entries != reg_enum_b->nr_entries) {
 110                 ret = -1;
 111                 goto end;
 112         }
 113         for (i = 0; i < reg_enum_a->nr_entries; i++) {
 114                 const struct ustctl_enum_entry *entries_a, *entries_b;
 115
 116                 entries_a = &reg_enum_a->entries[i];
 117                 entries_b = &reg_enum_b->entries[i];
 118                 if (entries_a->start.value != entries_b->start.value) {
 119                         ret = -1;
 120                         goto end;
 121                 }
 122                 if (entries_a->end.value != entries_b->end.value) {
 123                         ret = -1;
 124                         goto end;
 125                 }
 126                 if (entries_a->start.signedness != entries_b->start.signedness) {
 127                         ret = -1;
 128                         goto end;
 129                 }
 130                 if (entries_a->end.signedness != entries_b->end.signedness) {
 131                         ret = -1;
 132                         goto end;
 133                 }
 134
 135                 if (strcmp(entries_a->string, entries_b->string)) {
 136                         ret = -1;
 137                         goto end;
 138                 }
 139         }
 140 end:
 141         return ret;
 142 }
 143
 144 /*
 145  * Hash table match function for enumerations in the session. Match is
 146  * performed on enumeration name, and confirmed by comparing the enum
 147  * entries.
 148  */
 149 static int ht_match_enum(struct cds_lfht_node *node, const void *_key)
 150 {
 151         struct ust_registry_enum *_enum;
 152         const struct ust_registry_enum *key;
 153
 154         assert(node);
 155         assert(_key);
 156
 157         _enum = caa_container_of(node, struct ust_registry_enum,
 158                         node.node);
 159         assert(_enum);
 160         key = _key;
 161
 162         if (strncmp(_enum->name, key->name, LTTNG_UST_SYM_NAME_LEN)) {
 163                 goto no_match;
 164         }
 165         if (compare_enums(_enum, key)) {
 166                 goto no_match;
 167         }
 168
 169         /* Match. */
 170         return 1;
 171
 172 no_match:
 173         return 0;
 174 }
 175
 176 /*
 177  * Hash table match function for enumerations in the session. Match is
 178  * performed by enumeration ID.
 179  */
 180 static int ht_match_enum_id(struct cds_lfht_node *node, const void *_key)
 181 {
 182         struct ust_registry_enum *_enum;
 183         const struct ust_registry_enum *key = _key;
 184
 185         assert(node);
 186         assert(_key);
 187
 188         _enum = caa_container_of(node, struct ust_registry_enum, node.node);
 189         assert(_enum);
 190
 191         if (_enum->id != key->id) {
 192                 goto no_match;
 193         }
 194
 195         /* Match. */
 196         return 1;
 197
 198 no_match:
 199         return 0;
 200 }
 201
 202 /*
 203  * Hash table hash function for enumerations in the session. The
 204  * enumeration name is used for hashing.
 205  */
 206 static unsigned long ht_hash_enum(void *_key, unsigned long seed)
 207 {
 208         struct ust_registry_enum *key = _key;
 209
 210         assert(key);
 211         return hash_key_str(key->name, seed);
 212 }
 213
 214 /*
 215  * Return negative value on error, 0 if OK.
 216  *
 217  * TODO: we could add stricter verification of more types to catch
 218  * errors in liblttng-ust implementation earlier than consumption by the
 219  * trace reader.
 220  */
 221 static
 222 int validate_event_field(struct ustctl_field *field,
 223                 const char *event_name,
 224                 struct ust_app *app)
 225 {
 226         int ret = 0;
 227
 228         switch(field->type.atype) {
 229         case ustctl_atype_integer:
 230         case ustctl_atype_enum:
 231         case ustctl_atype_array:
 232         case ustctl_atype_sequence:
 233         case ustctl_atype_string:
 234         case ustctl_atype_variant:
 235                 break;
 236         case ustctl_atype_struct:
 237                 if (field->type.u._struct.nr_fields != 0) {
 238                         WARN("Unsupported non-empty struct field.");
 239                         ret = -EINVAL;
 240                         goto end;
 241                 }
 242                 break;
 243
 244         case ustctl_atype_float:
 245                 switch (field->type.u.basic._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.basic._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 ustctl_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 ustctl_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 = 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         assert(chan);
 370         assert(name);
 371         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 ustctl_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         assert(session);
 413         assert(name);
 414         assert(sig);
 415         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                         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         assert(chan);
 519         assert(event);
 520
 521         /* Delete the node first. */
 522         iter.iter.node = &event->node.node;
 523         ret = lttng_ht_del(chan->ht, &iter);
 524         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 struct ust_registry_enum *
 553         ust_registry_lookup_enum(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_SYM_NAME_LEN);
 587         reg_enum_lookup.name[LTTNG_UST_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 ustctl_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         assert(session);
 621         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 = 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_SYM_NAME_LEN);
 642         reg_enum->name[LTTNG_UST_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                 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 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         assert(reg_session);
 691         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         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         assert(chan);
 731
 732         if (notif) {
 733                 cmd_ret = notification_thread_command_remove_channel(
 734                                 notification_thread_handle, chan->consumer_key,
 735                                 LTTNG_DOMAIN_UST);
 736                 if (cmd_ret != LTTNG_OK) {
 737                         ERR("Failed to remove channel from notification thread");
 738                 }
 739         }
 740
 741         rcu_read_lock();
 742         /* Destroy all event associated with this registry. */
 743         cds_lfht_for_each_entry(chan->ht->ht, &iter.iter, event, node.node) {
 744                 /* Delete the node from the ht and free it. */
 745                 ust_registry_destroy_event(chan, event);
 746         }
 747         rcu_read_unlock();
 748         call_rcu(&chan->rcu_head, destroy_channel_rcu);
 749 }
 750
 751 /*
 752  * Initialize registry with default values.
 753  */
 754 int ust_registry_channel_add(struct ust_registry_session *session,
 755                 uint64_t key)
 756 {
 757         int ret = 0;
 758         struct ust_registry_channel *chan;
 759
 760         assert(session);
 761
 762         chan = zmalloc(sizeof(*chan));
 763         if (!chan) {
 764                 PERROR("zmalloc ust registry channel");
 765                 ret = -ENOMEM;
 766                 goto error_alloc;
 767         }
 768
 769         chan->ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 770         if (!chan->ht) {
 771                 ret = -ENOMEM;
 772                 goto error;
 773         }
 774
 775         /* Set custom match function. */
 776         chan->ht->match_fct = ht_match_event;
 777         chan->ht->hash_fct = ht_hash_event;
 778
 779         /*
 780          * Assign a channel ID right now since the event notification comes
 781          * *before* the channel notify so the ID needs to be set at this point so
 782          * the metadata can be dumped for that event.
 783          */
 784         if (ust_registry_is_max_id(session->used_channel_id)) {
 785                 ret = -1;
 786                 goto error;
 787         }
 788         chan->chan_id = ust_registry_get_next_chan_id(session);
 789
 790         rcu_read_lock();
 791         lttng_ht_node_init_u64(&chan->node, key);
 792         lttng_ht_add_unique_u64(session->channels, &chan->node);
 793         rcu_read_unlock();
 794
 795         return 0;
 796
 797 error:
 798         destroy_channel(chan, false);
 799 error_alloc:
 800         return ret;
 801 }
 802
 803 /*
 804  * Find a channel in the given registry. RCU read side lock MUST be acquired
 805  * before calling this function and as long as the event reference is kept by
 806  * the caller.
 807  *
 808  * On success, the pointer is returned else NULL.
 809  */
 810 struct ust_registry_channel *ust_registry_channel_find(
 811                 struct ust_registry_session *session, uint64_t key)
 812 {
 813         struct lttng_ht_node_u64 *node;
 814         struct lttng_ht_iter iter;
 815         struct ust_registry_channel *chan = NULL;
 816
 817         assert(session);
 818         assert(session->channels);
 819
 820         DBG3("UST registry channel finding key %" PRIu64, key);
 821
 822         lttng_ht_lookup(session->channels, &key, &iter);
 823         node = lttng_ht_iter_get_node_u64(&iter);
 824         if (!node) {
 825                 goto end;
 826         }
 827         chan = caa_container_of(node, struct ust_registry_channel, node);
 828
 829 end:
 830         return chan;
 831 }
 832
 833 /*
 834  * Remove channel using key from registry and free memory.
 835  */
 836 void ust_registry_channel_del_free(struct ust_registry_session *session,
 837                 uint64_t key, bool notif)
 838 {
 839         struct lttng_ht_iter iter;
 840         struct ust_registry_channel *chan;
 841         int ret;
 842
 843         assert(session);
 844
 845         rcu_read_lock();
 846         chan = ust_registry_channel_find(session, key);
 847         if (!chan) {
 848                 rcu_read_unlock();
 849                 goto end;
 850         }
 851
 852         iter.iter.node = &chan->node.node;
 853         ret = lttng_ht_del(session->channels, &iter);
 854         assert(!ret);
 855         rcu_read_unlock();
 856         destroy_channel(chan, notif);
 857
 858 end:
 859         return;
 860 }
 861
 862 /*
 863  * Initialize registry with default values and set the newly allocated session
 864  * pointer to sessionp.
 865  *
 866  * Return 0 on success and sessionp is set or else return -1 and sessionp is
 867  * kept untouched.
 868  */
 869 int ust_registry_session_init(struct ust_registry_session **sessionp,
 870                 struct ust_app *app,
 871                 uint32_t bits_per_long,
 872                 uint32_t uint8_t_alignment,
 873                 uint32_t uint16_t_alignment,
 874                 uint32_t uint32_t_alignment,
 875                 uint32_t uint64_t_alignment,
 876                 uint32_t long_alignment,
 877                 int byte_order,
 878                 uint32_t major,
 879                 uint32_t minor,
 880                 const char *root_shm_path,
 881                 const char *shm_path,
 882                 uid_t euid,
 883                 gid_t egid)
 884 {
 885         int ret;
 886         struct ust_registry_session *session;
 887
 888         assert(sessionp);
 889
 890         session = zmalloc(sizeof(*session));
 891         if (!session) {
 892                 PERROR("zmalloc ust registry session");
 893                 goto error_alloc;
 894         }
 895
 896         pthread_mutex_init(&session->lock, NULL);
 897         session->bits_per_long = bits_per_long;
 898         session->uint8_t_alignment = uint8_t_alignment;
 899         session->uint16_t_alignment = uint16_t_alignment;
 900         session->uint32_t_alignment = uint32_t_alignment;
 901         session->uint64_t_alignment = uint64_t_alignment;
 902         session->long_alignment = long_alignment;
 903         session->byte_order = byte_order;
 904         session->metadata_fd = -1;
 905         session->uid = euid;
 906         session->gid = egid;
 907         session->next_enum_id = 0;
 908         session->major = major;
 909         session->minor = minor;
 910         strncpy(session->root_shm_path, root_shm_path,
 911                 sizeof(session->root_shm_path));
 912         session->root_shm_path[sizeof(session->root_shm_path) - 1] = '\0';
 913         if (shm_path[0]) {
 914                 strncpy(session->shm_path, shm_path,
 915                         sizeof(session->shm_path));
 916                 session->shm_path[sizeof(session->shm_path) - 1] = '\0';
 917                 strncpy(session->metadata_path, shm_path,
 918                         sizeof(session->metadata_path));
 919                 session->metadata_path[sizeof(session->metadata_path) - 1] = '\0';
 920                 strncat(session->metadata_path, "/metadata",
 921                         sizeof(session->metadata_path)
 922                                 - strlen(session->metadata_path) - 1);
 923         }
 924         if (session->shm_path[0]) {
 925                 ret = run_as_mkdir_recursive(session->shm_path,
 926                         S_IRWXU | S_IRWXG,
 927                         euid, egid);
 928                 if (ret) {
 929                         PERROR("run_as_mkdir_recursive");
 930                         goto error;
 931                 }
 932         }
 933         if (session->metadata_path[0]) {
 934                 /* Create metadata file */
 935                 ret = run_as_open(session->metadata_path,
 936                         O_WRONLY | O_CREAT | O_EXCL,
 937                         S_IRUSR | S_IWUSR, euid, egid);
 938                 if (ret < 0) {
 939                         PERROR("Opening metadata file");
 940                         goto error;
 941                 }
 942                 session->metadata_fd = ret;
 943         }
 944
 945         session->enums = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 946         if (!session->enums) {
 947                 ERR("Failed to create enums hash table");
 948                 goto error;
 949         }
 950         /* hash/match functions are specified at call site. */
 951         session->enums->match_fct = NULL;
 952         session->enums->hash_fct = NULL;
 953
 954         session->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 955         if (!session->channels) {
 956                 goto error;
 957         }
 958
 959         ret = lttng_uuid_generate(session->uuid);
 960         if (ret) {
 961                 ERR("Failed to generate UST uuid (errno = %d)", ret);
 962                 goto error;
 963         }
 964
 965         pthread_mutex_lock(&session->lock);
 966         ret = ust_metadata_session_statedump(session, app, major, minor);
 967         pthread_mutex_unlock(&session->lock);
 968         if (ret) {
 969                 ERR("Failed to generate session metadata (errno = %d)", ret);
 970                 goto error;
 971         }
 972
 973         *sessionp = session;
 974
 975         return 0;
 976
 977 error:
 978         ust_registry_session_destroy(session);
 979         free(session);
 980 error_alloc:
 981         return -1;
 982 }
 983
 984 /*
 985  * Destroy session registry. This does NOT free the given pointer since it
 986  * might get passed as a reference. The registry lock should NOT be acquired.
 987  */
 988 void ust_registry_session_destroy(struct ust_registry_session *reg)
 989 {
 990         int ret;
 991         struct lttng_ht_iter iter;
 992         struct ust_registry_channel *chan;
 993         struct ust_registry_enum *reg_enum;
 994
 995         if (!reg) {
 996                 return;
 997         }
 998
 999         /* On error, EBUSY can be returned if lock. Code flow error. */
1000         ret = pthread_mutex_destroy(&reg->lock);
1001         assert(!ret);
1002
1003         if (reg->channels) {
1004                 rcu_read_lock();
1005                 /* Destroy all event associated with this registry. */
1006                 cds_lfht_for_each_entry(reg->channels->ht, &iter.iter, chan,
1007                                 node.node) {
1008                         /* Delete the node from the ht and free it. */
1009                         ret = lttng_ht_del(reg->channels, &iter);
1010                         assert(!ret);
1011                         destroy_channel(chan, true);
1012                 }
1013                 rcu_read_unlock();
1014                 ht_cleanup_push(reg->channels);
1015         }
1016
1017         free(reg->metadata);
1018         if (reg->metadata_fd >= 0) {
1019                 ret = close(reg->metadata_fd);
1020                 if (ret) {
1021                         PERROR("close");
1022                 }
1023                 ret = run_as_unlink(reg->metadata_path,
1024                                 reg->uid, reg->gid);
1025                 if (ret) {
1026                         PERROR("unlink");
1027                 }
1028         }
1029         if (reg->root_shm_path[0]) {
1030                 /*
1031                  * Try deleting the directory hierarchy.
1032                  */
1033                 (void) run_as_rmdir_recursive(reg->root_shm_path,
1034                                 reg->uid, reg->gid);
1035         }
1036         /* Destroy the enum hash table */
1037         if (reg->enums) {
1038                 rcu_read_lock();
1039                 /* Destroy all enum entries associated with this registry. */
1040                 cds_lfht_for_each_entry(reg->enums->ht, &iter.iter, reg_enum,
1041                                 node.node) {
1042                         ust_registry_destroy_enum(reg, reg_enum);
1043                 }
1044                 rcu_read_unlock();
1045                 ht_cleanup_push(reg->enums);
1046         }
1047 }