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