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 #define _GNU_SOURCE
  18 #include <assert.h>
  19 #include <inttypes.h>
  20
  21 #include <common/common.h>
  22 #include <common/hashtable/utils.h>
  23 #include <lttng/lttng.h>
  24
  25 #include "ust-registry.h"
  26 #include "ust-app.h"
  27 #include "utils.h"
  28
  29 /*
  30  * Hash table match function for event in the registry.
  31  */
  32 static int ht_match_event(struct cds_lfht_node *node, const void *_key)
  33 {
  34         struct ust_registry_event *event;
  35         const struct ust_registry_event *key;
  36
  37         assert(node);
  38         assert(_key);
  39
  40         event = caa_container_of(node, struct ust_registry_event, node.node);
  41         assert(event);
  42         key = _key;
  43
  44         /* It has to be a perfect match. */
  45         if (strncmp(event->name, key->name, sizeof(event->name)) != 0) {
  46                 goto no_match;
  47         }
  48
  49         /* It has to be a perfect match. */
  50         if (strncmp(event->signature, key->signature,
  51                                 strlen(event->signature) != 0)) {
  52                 goto no_match;
  53         }
  54
  55         /* Match */
  56         return 1;
  57
  58 no_match:
  59         return 0;
  60 }
  61
  62 static unsigned long ht_hash_event(void *_key, unsigned long seed)
  63 {
  64         uint64_t xored_key;
  65         struct ust_registry_event *key = _key;
  66
  67         assert(key);
  68
  69         xored_key = (uint64_t) (hash_key_str(key->name, seed) ^
  70                         hash_key_str(key->signature, seed));
  71
  72         return hash_key_u64(&xored_key, seed);
  73 }
  74
  75 /*
  76  * Return negative value on error, 0 if OK.
  77  *
  78  * TODO: we could add stricter verification of more types to catch
  79  * errors in liblttng-ust implementation earlier than consumption by the
  80  * trace reader.
  81  */
  82 static
  83 int validate_event_field(struct ustctl_field *field,
  84                 const char *event_name,
  85                 struct ust_app *app)
  86 {
  87         switch(field->type.atype) {
  88         case ustctl_atype_integer:
  89         case ustctl_atype_enum:
  90         case ustctl_atype_array:
  91         case ustctl_atype_sequence:
  92         case ustctl_atype_string:
  93                 break;
  94
  95         case ustctl_atype_float:
  96                 switch (field->type.u.basic._float.mant_dig) {
  97                 case 0:
  98                         WARN("UST application '%s' (pid: %d) has unknown float mantissa '%u' "
  99                                 "in field '%s', rejecting event '%s'",
 100                                 app->name, app->pid,
 101                                 field->type.u.basic._float.mant_dig,
 102                                 field->name,
 103                                 event_name);
 104                         return -EINVAL;
 105                 default:
 106                         break;
 107                 }
 108                 break;
 109
 110         default:
 111                 return -ENOENT;
 112         }
 113         return 0;
 114 }
 115
 116 static
 117 int validate_event_fields(size_t nr_fields, struct ustctl_field *fields,
 118                 const char *event_name, struct ust_app *app)
 119 {
 120         unsigned int i;
 121
 122         for (i = 0; i < nr_fields; i++) {
 123                 if (validate_event_field(&fields[i], event_name, app) < 0)
 124                         return -EINVAL;
 125         }
 126         return 0;
 127 }
 128
 129 /*
 130  * Allocate event and initialize it. This does NOT set a valid event id from a
 131  * registry.
 132  */
 133 static struct ust_registry_event *alloc_event(int session_objd,
 134                 int channel_objd, char *name, char *sig, size_t nr_fields,
 135                 struct ustctl_field *fields, int loglevel, char *model_emf_uri,
 136                 struct ust_app *app)
 137 {
 138         struct ust_registry_event *event = NULL;
 139
 140         /*
 141          * Ensure that the field content is valid.
 142          */
 143         if (validate_event_fields(nr_fields, fields, name, app) < 0) {
 144                 return NULL;
 145         }
 146
 147         event = zmalloc(sizeof(*event));
 148         if (!event) {
 149                 PERROR("zmalloc ust registry event");
 150                 goto error;
 151         }
 152
 153         event->session_objd = session_objd;
 154         event->channel_objd = channel_objd;
 155         /* Allocated by ustctl. */
 156         event->signature = sig;
 157         event->nr_fields = nr_fields;
 158         event->fields = fields;
 159         event->loglevel = loglevel;
 160         event->model_emf_uri = model_emf_uri;
 161         if (name) {
 162                 /* Copy event name and force NULL byte. */
 163                 strncpy(event->name, name, sizeof(event->name));
 164                 event->name[sizeof(event->name) - 1] = '\0';
 165         }
 166         cds_lfht_node_init(&event->node.node);
 167
 168 error:
 169         return event;
 170 }
 171
 172 /*
 173  * Free event data structure. This does NOT delete it from any hash table. It's
 174  * safe to pass a NULL pointer. This shoudl be called inside a call RCU if the
 175  * event is previously deleted from a rcu hash table.
 176  */
 177 static void destroy_event(struct ust_registry_event *event)
 178 {
 179         if (!event) {
 180                 return;
 181         }
 182
 183         free(event->fields);
 184         free(event->model_emf_uri);
 185         free(event->signature);
 186         free(event);
 187 }
 188
 189 /*
 190  * Destroy event function call of the call RCU.
 191  */
 192 static void destroy_event_rcu(struct rcu_head *head)
 193 {
 194         struct lttng_ht_node_u64 *node =
 195                 caa_container_of(head, struct lttng_ht_node_u64, head);
 196         struct ust_registry_event *event =
 197                 caa_container_of(node, struct ust_registry_event, node);
 198
 199         destroy_event(event);
 200 }
 201
 202 /*
 203  * Find an event using the name and signature in the given registry. RCU read
 204  * side lock MUST be acquired before calling this function and as long as the
 205  * event reference is kept by the caller.
 206  *
 207  * On success, the event pointer is returned else NULL.
 208  */
 209 struct ust_registry_event *ust_registry_find_event(
 210                 struct ust_registry_channel *chan, char *name, char *sig)
 211 {
 212         struct lttng_ht_node_u64 *node;
 213         struct lttng_ht_iter iter;
 214         struct ust_registry_event *event = NULL;
 215         struct ust_registry_event key;
 216
 217         assert(chan);
 218         assert(name);
 219         assert(sig);
 220
 221         /* Setup key for the match function. */
 222         strncpy(key.name, name, sizeof(key.name));
 223         key.name[sizeof(key.name) - 1] = '\0';
 224         key.signature = sig;
 225
 226         cds_lfht_lookup(chan->ht->ht, chan->ht->hash_fct(&key, lttng_ht_seed),
 227                         chan->ht->match_fct, &key, &iter.iter);
 228         node = lttng_ht_iter_get_node_u64(&iter);
 229         if (!node) {
 230                 goto end;
 231         }
 232         event = caa_container_of(node, struct ust_registry_event, node);
 233
 234 end:
 235         return event;
 236 }
 237
 238 /*
 239  * Create a ust_registry_event from the given parameters and add it to the
 240  * registry hash table. If event_id is valid, it is set with the newly created
 241  * event id.
 242  *
 243  * On success, return 0 else a negative value. The created event MUST be unique
 244  * so on duplicate entry -EINVAL is returned. On error, event_id is untouched.
 245  *
 246  * Should be called with session registry mutex held.
 247  */
 248 int ust_registry_create_event(struct ust_registry_session *session,
 249                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 250                 char *sig, size_t nr_fields, struct ustctl_field *fields, int loglevel,
 251                 char *model_emf_uri, int buffer_type, uint32_t *event_id_p,
 252                 struct ust_app *app)
 253 {
 254         int ret;
 255         uint32_t event_id;
 256         struct cds_lfht_node *nptr;
 257         struct ust_registry_event *event = NULL;
 258         struct ust_registry_channel *chan;
 259
 260         assert(session);
 261         assert(name);
 262         assert(sig);
 263         assert(event_id_p);
 264
 265         rcu_read_lock();
 266
 267         /*
 268          * This should not happen but since it comes from the UST tracer, an
 269          * external party, don't assert and simply validate values.
 270          */
 271         if (session_objd < 0 || channel_objd < 0) {
 272                 ret = -EINVAL;
 273                 goto error_free;
 274         }
 275
 276         chan = ust_registry_channel_find(session, chan_key);
 277         if (!chan) {
 278                 ret = -EINVAL;
 279                 goto error_free;
 280         }
 281
 282         /* Check if we've reached the maximum possible id. */
 283         if (ust_registry_is_max_id(chan->used_event_id)) {
 284                 ret = -ENOENT;
 285                 goto error_free;
 286         }
 287
 288         event = alloc_event(session_objd, channel_objd, name, sig, nr_fields,
 289                         fields, loglevel, model_emf_uri, app);
 290         if (!event) {
 291                 ret = -ENOMEM;
 292                 goto error_free;
 293         }
 294
 295         DBG3("UST registry creating event with event: %s, sig: %s, id: %u, "
 296                         "chan_objd: %u, sess_objd: %u, chan_id: %u", event->name,
 297                         event->signature, event->id, event->channel_objd,
 298                         event->session_objd, chan->chan_id);
 299
 300         /*
 301          * This is an add unique with a custom match function for event. The node
 302          * are matched using the event name and signature.
 303          */
 304         nptr = cds_lfht_add_unique(chan->ht->ht, chan->ht->hash_fct(event,
 305                                 lttng_ht_seed), chan->ht->match_fct, event, &event->node.node);
 306         if (nptr != &event->node.node) {
 307                 if (buffer_type == LTTNG_BUFFER_PER_UID) {
 308                         /*
 309                          * This is normal, we just have to send the event id of the
 310                          * returned node and make sure we destroy the previously allocated
 311                          * event object.
 312                          */
 313                         destroy_event(event);
 314                         event = caa_container_of(nptr, struct ust_registry_event,
 315                                         node.node);
 316                         assert(event);
 317                         event_id = event->id;
 318                 } else {
 319                         ERR("UST registry create event add unique failed for event: %s, "
 320                                         "sig: %s, id: %u, chan_objd: %u, sess_objd: %u",
 321                                         event->name, event->signature, event->id,
 322                                         event->channel_objd, event->session_objd);
 323                         ret = -EINVAL;
 324                         goto error_unlock;
 325                 }
 326         } else {
 327                 /* Request next event id if the node was successfully added. */
 328                 event_id = event->id = ust_registry_get_next_event_id(chan);
 329         }
 330
 331         *event_id_p = event_id;
 332
 333         if (!event->metadata_dumped) {
 334                 /* Append to metadata */
 335                 ret = ust_metadata_event_statedump(session, chan, event);
 336                 if (ret) {
 337                         ERR("Error appending event metadata (errno = %d)", ret);
 338                         rcu_read_unlock();
 339                         return ret;
 340                 }
 341         }
 342
 343         rcu_read_unlock();
 344         return 0;
 345
 346 error_free:
 347         free(sig);
 348         free(fields);
 349         free(model_emf_uri);
 350 error_unlock:
 351         rcu_read_unlock();
 352         destroy_event(event);
 353         return ret;
 354 }
 355
 356 /*
 357  * For a given event in a registry, delete the entry and destroy the event.
 358  * This MUST be called within a RCU read side lock section.
 359  */
 360 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 361                 struct ust_registry_event *event)
 362 {
 363         int ret;
 364         struct lttng_ht_iter iter;
 365
 366         assert(chan);
 367         assert(event);
 368
 369         /* Delete the node first. */
 370         iter.iter.node = &event->node.node;
 371         ret = lttng_ht_del(chan->ht, &iter);
 372         assert(!ret);
 373
 374         call_rcu(&event->node.head, destroy_event_rcu);
 375
 376         return;
 377 }
 378
 379 /*
 380  * We need to execute ht_destroy outside of RCU read-side critical
 381  * section and outside of call_rcu thread, so we postpone its execution
 382  * using ht_cleanup_push. It is simpler than to change the semantic of
 383  * the many callers of delete_ust_app_session().
 384  */
 385 static
 386 void destroy_channel_rcu(struct rcu_head *head)
 387 {
 388         struct ust_registry_channel *chan =
 389                 caa_container_of(head, struct ust_registry_channel, rcu_head);
 390
 391         if (chan->ht) {
 392                 ht_cleanup_push(chan->ht);
 393         }
 394         free(chan->ctx_fields);
 395         free(chan);
 396 }
 397
 398 /*
 399  * Destroy every element of the registry and free the memory. This does NOT
 400  * free the registry pointer since it might not have been allocated before so
 401  * it's the caller responsability.
 402  */
 403 static void destroy_channel(struct ust_registry_channel *chan)
 404 {
 405         struct lttng_ht_iter iter;
 406         struct ust_registry_event *event;
 407
 408         assert(chan);
 409
 410         rcu_read_lock();
 411         /* Destroy all event associated with this registry. */
 412         cds_lfht_for_each_entry(chan->ht->ht, &iter.iter, event, node.node) {
 413                 /* Delete the node from the ht and free it. */
 414                 ust_registry_destroy_event(chan, event);
 415         }
 416         rcu_read_unlock();
 417         call_rcu(&chan->rcu_head, destroy_channel_rcu);
 418 }
 419
 420 /*
 421  * Initialize registry with default values.
 422  */
 423 int ust_registry_channel_add(struct ust_registry_session *session,
 424                 uint64_t key)
 425 {
 426         int ret = 0;
 427         struct ust_registry_channel *chan;
 428
 429         assert(session);
 430
 431         chan = zmalloc(sizeof(*chan));
 432         if (!chan) {
 433                 PERROR("zmalloc ust registry channel");
 434                 ret = -ENOMEM;
 435                 goto error_alloc;
 436         }
 437
 438         chan->ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 439         if (!chan->ht) {
 440                 ret = -ENOMEM;
 441                 goto error;
 442         }
 443
 444         /* Set custom match function. */
 445         chan->ht->match_fct = ht_match_event;
 446         chan->ht->hash_fct = ht_hash_event;
 447
 448         /*
 449          * Assign a channel ID right now since the event notification comes
 450          * *before* the channel notify so the ID needs to be set at this point so
 451          * the metadata can be dumped for that event.
 452          */
 453         if (ust_registry_is_max_id(session->used_channel_id)) {
 454                 ret = -1;
 455                 goto error;
 456         }
 457         chan->chan_id = ust_registry_get_next_chan_id(session);
 458
 459         rcu_read_lock();
 460         lttng_ht_node_init_u64(&chan->node, key);
 461         lttng_ht_add_unique_u64(session->channels, &chan->node);
 462         rcu_read_unlock();
 463
 464         return 0;
 465
 466 error:
 467         destroy_channel(chan);
 468 error_alloc:
 469         return ret;
 470 }
 471
 472 /*
 473  * Find a channel in the given registry. RCU read side lock MUST be acquired
 474  * before calling this function and as long as the event reference is kept by
 475  * the caller.
 476  *
 477  * On success, the pointer is returned else NULL.
 478  */
 479 struct ust_registry_channel *ust_registry_channel_find(
 480                 struct ust_registry_session *session, uint64_t key)
 481 {
 482         struct lttng_ht_node_u64 *node;
 483         struct lttng_ht_iter iter;
 484         struct ust_registry_channel *chan = NULL;
 485
 486         assert(session);
 487         assert(session->channels);
 488
 489         DBG3("UST registry channel finding key %" PRIu64, key);
 490
 491         lttng_ht_lookup(session->channels, &key, &iter);
 492         node = lttng_ht_iter_get_node_u64(&iter);
 493         if (!node) {
 494                 goto end;
 495         }
 496         chan = caa_container_of(node, struct ust_registry_channel, node);
 497
 498 end:
 499         return chan;
 500 }
 501
 502 /*
 503  * Remove channel using key from registry and free memory.
 504  */
 505 void ust_registry_channel_del_free(struct ust_registry_session *session,
 506                 uint64_t key)
 507 {
 508         struct lttng_ht_iter iter;
 509         struct ust_registry_channel *chan;
 510         int ret;
 511
 512         assert(session);
 513
 514         rcu_read_lock();
 515         chan = ust_registry_channel_find(session, key);
 516         if (!chan) {
 517                 rcu_read_unlock();
 518                 goto end;
 519         }
 520
 521         iter.iter.node = &chan->node.node;
 522         ret = lttng_ht_del(session->channels, &iter);
 523         assert(!ret);
 524         rcu_read_unlock();
 525         destroy_channel(chan);
 526
 527 end:
 528         return;
 529 }
 530
 531 /*
 532  * Initialize registry with default values and set the newly allocated session
 533  * pointer to sessionp.
 534  *
 535  * Return 0 on success and sessionp is set or else return -1 and sessionp is
 536  * kept untouched.
 537  */
 538 int ust_registry_session_init(struct ust_registry_session **sessionp,
 539                 struct ust_app *app,
 540                 uint32_t bits_per_long,
 541                 uint32_t uint8_t_alignment,
 542                 uint32_t uint16_t_alignment,
 543                 uint32_t uint32_t_alignment,
 544                 uint32_t uint64_t_alignment,
 545                 uint32_t long_alignment,
 546                 int byte_order,
 547                 uint32_t major,
 548                 uint32_t minor)
 549 {
 550         int ret;
 551         struct ust_registry_session *session;
 552
 553         assert(sessionp);
 554
 555         session = zmalloc(sizeof(*session));
 556         if (!session) {
 557                 PERROR("zmalloc ust registry session");
 558                 goto error_alloc;
 559         }
 560
 561         pthread_mutex_init(&session->lock, NULL);
 562         session->bits_per_long = bits_per_long;
 563         session->uint8_t_alignment = uint8_t_alignment;
 564         session->uint16_t_alignment = uint16_t_alignment;
 565         session->uint32_t_alignment = uint32_t_alignment;
 566         session->uint64_t_alignment = uint64_t_alignment;
 567         session->long_alignment = long_alignment;
 568         session->byte_order = byte_order;
 569
 570         session->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 571         if (!session->channels) {
 572                 goto error;
 573         }
 574
 575         ret = lttng_uuid_generate(session->uuid);
 576         if (ret) {
 577                 ERR("Failed to generate UST uuid (errno = %d)", ret);
 578                 goto error;
 579         }
 580
 581         pthread_mutex_lock(&session->lock);
 582         ret = ust_metadata_session_statedump(session, app, major, minor);
 583         pthread_mutex_unlock(&session->lock);
 584         if (ret) {
 585                 ERR("Failed to generate session metadata (errno = %d)", ret);
 586                 goto error;
 587         }
 588
 589         *sessionp = session;
 590
 591         return 0;
 592
 593 error:
 594         ust_registry_session_destroy(session);
 595         free(session);
 596 error_alloc:
 597         return -1;
 598 }
 599
 600 /*
 601  * Destroy session registry. This does NOT free the given pointer since it
 602  * might get passed as a reference. The registry lock should NOT be acquired.
 603  */
 604 void ust_registry_session_destroy(struct ust_registry_session *reg)
 605 {
 606         int ret;
 607         struct lttng_ht_iter iter;
 608         struct ust_registry_channel *chan;
 609
 610         assert(reg);
 611
 612         /* On error, EBUSY can be returned if lock. Code flow error. */
 613         ret = pthread_mutex_destroy(&reg->lock);
 614         assert(!ret);
 615
 616         if (reg->channels) {
 617                 rcu_read_lock();
 618                 /* Destroy all event associated with this registry. */
 619                 cds_lfht_for_each_entry(reg->channels->ht, &iter.iter, chan,
 620                                 node.node) {
 621                         /* Delete the node from the ht and free it. */
 622                         ret = lttng_ht_del(reg->channels, &iter);
 623                         assert(!ret);
 624                         destroy_channel(chan);
 625                 }
 626                 rcu_read_unlock();
 627                 ht_cleanup_push(reg->channels);
 628         }
 629
 630         free(reg->metadata);
 631 }