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 #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)) != 0) {
  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) != 0)) {
  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 /*
  77  * Return negative value on error, 0 if OK.
  78  *
  79  * TODO: we could add stricter verification of more types to catch
  80  * errors in liblttng-ust implementation earlier than consumption by the
  81  * trace reader.
  82  */
  83 static
  84 int validate_event_field(struct ustctl_field *field,
  85                 const char *event_name,
  86                 struct ust_app *app)
  87 {
  88         switch(field->type.atype) {
  89         case ustctl_atype_integer:
  90         case ustctl_atype_enum:
  91         case ustctl_atype_array:
  92         case ustctl_atype_sequence:
  93         case ustctl_atype_string:
  94                 break;
  95
  96         case ustctl_atype_float:
  97                 switch (field->type.u.basic._float.mant_dig) {
  98                 case 0:
  99                         WARN("UST application '%s' (pid: %d) has unknown float mantissa '%u' "
 100                                 "in field '%s', rejecting event '%s'",
 101                                 app->name, app->pid,
 102                                 field->type.u.basic._float.mant_dig,
 103                                 field->name,
 104                                 event_name);
 105                         return -EINVAL;
 106                 default:
 107                         break;
 108                 }
 109                 break;
 110
 111         default:
 112                 return -ENOENT;
 113         }
 114         return 0;
 115 }
 116
 117 static
 118 int validate_event_fields(size_t nr_fields, struct ustctl_field *fields,
 119                 const char *event_name, struct ust_app *app)
 120 {
 121         unsigned int i;
 122
 123         for (i = 0; i < nr_fields; i++) {
 124                 if (validate_event_field(&fields[i], event_name, app) < 0)
 125                         return -EINVAL;
 126         }
 127         return 0;
 128 }
 129
 130 /*
 131  * Allocate event and initialize it. This does NOT set a valid event id from a
 132  * registry.
 133  */
 134 static struct ust_registry_event *alloc_event(int session_objd,
 135                 int channel_objd, char *name, char *sig, size_t nr_fields,
 136                 struct ustctl_field *fields, int loglevel, char *model_emf_uri,
 137                 struct ust_app *app)
 138 {
 139         struct ust_registry_event *event = NULL;
 140
 141         /*
 142          * Ensure that the field content is valid.
 143          */
 144         if (validate_event_fields(nr_fields, fields, name, app) < 0) {
 145                 return NULL;
 146         }
 147
 148         event = zmalloc(sizeof(*event));
 149         if (!event) {
 150                 PERROR("zmalloc ust registry event");
 151                 goto error;
 152         }
 153
 154         event->session_objd = session_objd;
 155         event->channel_objd = channel_objd;
 156         /* Allocated by ustctl. */
 157         event->signature = sig;
 158         event->nr_fields = nr_fields;
 159         event->fields = fields;
 160         event->loglevel = loglevel;
 161         event->model_emf_uri = model_emf_uri;
 162         if (name) {
 163                 /* Copy event name and force NULL byte. */
 164                 strncpy(event->name, name, sizeof(event->name));
 165                 event->name[sizeof(event->name) - 1] = '\0';
 166         }
 167         cds_lfht_node_init(&event->node.node);
 168
 169 error:
 170         return event;
 171 }
 172
 173 /*
 174  * Free event data structure. This does NOT delete it from any hash table. It's
 175  * safe to pass a NULL pointer. This shoudl be called inside a call RCU if the
 176  * event is previously deleted from a rcu hash table.
 177  */
 178 static void destroy_event(struct ust_registry_event *event)
 179 {
 180         if (!event) {
 181                 return;
 182         }
 183
 184         free(event->fields);
 185         free(event->model_emf_uri);
 186         free(event->signature);
 187         free(event);
 188 }
 189
 190 /*
 191  * Destroy event function call of the call RCU.
 192  */
 193 static void destroy_event_rcu(struct rcu_head *head)
 194 {
 195         struct lttng_ht_node_u64 *node =
 196                 caa_container_of(head, struct lttng_ht_node_u64, head);
 197         struct ust_registry_event *event =
 198                 caa_container_of(node, struct ust_registry_event, node);
 199
 200         destroy_event(event);
 201 }
 202
 203 /*
 204  * Find an event using the name and signature in the given registry. RCU read
 205  * side lock MUST be acquired before calling this function and as long as the
 206  * event reference is kept by the caller.
 207  *
 208  * On success, the event pointer is returned else NULL.
 209  */
 210 struct ust_registry_event *ust_registry_find_event(
 211                 struct ust_registry_channel *chan, char *name, char *sig)
 212 {
 213         struct lttng_ht_node_u64 *node;
 214         struct lttng_ht_iter iter;
 215         struct ust_registry_event *event = NULL;
 216         struct ust_registry_event key;
 217
 218         assert(chan);
 219         assert(name);
 220         assert(sig);
 221
 222         /* Setup key for the match function. */
 223         strncpy(key.name, name, sizeof(key.name));
 224         key.name[sizeof(key.name) - 1] = '\0';
 225         key.signature = sig;
 226
 227         cds_lfht_lookup(chan->ht->ht, chan->ht->hash_fct(&key, lttng_ht_seed),
 228                         chan->ht->match_fct, &key, &iter.iter);
 229         node = lttng_ht_iter_get_node_u64(&iter);
 230         if (!node) {
 231                 goto end;
 232         }
 233         event = caa_container_of(node, struct ust_registry_event, node);
 234
 235 end:
 236         return event;
 237 }
 238
 239 /*
 240  * Create a ust_registry_event from the given parameters and add it to the
 241  * registry hash table. If event_id is valid, it is set with the newly created
 242  * event id.
 243  *
 244  * On success, return 0 else a negative value. The created event MUST be unique
 245  * so on duplicate entry -EINVAL is returned. On error, event_id is untouched.
 246  *
 247  * Should be called with session registry mutex held.
 248  */
 249 int ust_registry_create_event(struct ust_registry_session *session,
 250                 uint64_t chan_key, int session_objd, int channel_objd, char *name,
 251                 char *sig, size_t nr_fields, struct ustctl_field *fields, int loglevel,
 252                 char *model_emf_uri, int buffer_type, uint32_t *event_id_p,
 253                 struct ust_app *app)
 254 {
 255         int ret;
 256         uint32_t event_id;
 257         struct cds_lfht_node *nptr;
 258         struct ust_registry_event *event = NULL;
 259         struct ust_registry_channel *chan;
 260
 261         assert(session);
 262         assert(name);
 263         assert(sig);
 264         assert(event_id_p);
 265
 266         rcu_read_lock();
 267
 268         /*
 269          * This should not happen but since it comes from the UST tracer, an
 270          * external party, don't assert and simply validate values.
 271          */
 272         if (session_objd < 0 || channel_objd < 0) {
 273                 ret = -EINVAL;
 274                 goto error_free;
 275         }
 276
 277         chan = ust_registry_channel_find(session, chan_key);
 278         if (!chan) {
 279                 ret = -EINVAL;
 280                 goto error_free;
 281         }
 282
 283         /* Check if we've reached the maximum possible id. */
 284         if (ust_registry_is_max_id(chan->used_event_id)) {
 285                 ret = -ENOENT;
 286                 goto error_free;
 287         }
 288
 289         event = alloc_event(session_objd, channel_objd, name, sig, nr_fields,
 290                         fields, loglevel, model_emf_uri, app);
 291         if (!event) {
 292                 ret = -ENOMEM;
 293                 goto error_free;
 294         }
 295
 296         DBG3("UST registry creating event with event: %s, sig: %s, id: %u, "
 297                         "chan_objd: %u, sess_objd: %u, chan_id: %u", event->name,
 298                         event->signature, event->id, event->channel_objd,
 299                         event->session_objd, chan->chan_id);
 300
 301         /*
 302          * This is an add unique with a custom match function for event. The node
 303          * are matched using the event name and signature.
 304          */
 305         nptr = cds_lfht_add_unique(chan->ht->ht, chan->ht->hash_fct(event,
 306                                 lttng_ht_seed), chan->ht->match_fct, event, &event->node.node);
 307         if (nptr != &event->node.node) {
 308                 if (buffer_type == LTTNG_BUFFER_PER_UID) {
 309                         /*
 310                          * This is normal, we just have to send the event id of the
 311                          * returned node and make sure we destroy the previously allocated
 312                          * event object.
 313                          */
 314                         destroy_event(event);
 315                         event = caa_container_of(nptr, struct ust_registry_event,
 316                                         node.node);
 317                         assert(event);
 318                         event_id = event->id;
 319                 } else {
 320                         ERR("UST registry create event add unique failed for event: %s, "
 321                                         "sig: %s, id: %u, chan_objd: %u, sess_objd: %u",
 322                                         event->name, event->signature, event->id,
 323                                         event->channel_objd, event->session_objd);
 324                         ret = -EINVAL;
 325                         goto error_unlock;
 326                 }
 327         } else {
 328                 /* Request next event id if the node was successfully added. */
 329                 event_id = event->id = ust_registry_get_next_event_id(chan);
 330         }
 331
 332         *event_id_p = event_id;
 333
 334         if (!event->metadata_dumped) {
 335                 /* Append to metadata */
 336                 ret = ust_metadata_event_statedump(session, chan, event);
 337                 if (ret) {
 338                         ERR("Error appending event metadata (errno = %d)", ret);
 339                         rcu_read_unlock();
 340                         return ret;
 341                 }
 342         }
 343
 344         rcu_read_unlock();
 345         return 0;
 346
 347 error_free:
 348         free(sig);
 349         free(fields);
 350         free(model_emf_uri);
 351 error_unlock:
 352         rcu_read_unlock();
 353         destroy_event(event);
 354         return ret;
 355 }
 356
 357 /*
 358  * For a given event in a registry, delete the entry and destroy the event.
 359  * This MUST be called within a RCU read side lock section.
 360  */
 361 void ust_registry_destroy_event(struct ust_registry_channel *chan,
 362                 struct ust_registry_event *event)
 363 {
 364         int ret;
 365         struct lttng_ht_iter iter;
 366
 367         assert(chan);
 368         assert(event);
 369
 370         /* Delete the node first. */
 371         iter.iter.node = &event->node.node;
 372         ret = lttng_ht_del(chan->ht, &iter);
 373         assert(!ret);
 374
 375         call_rcu(&event->node.head, destroy_event_rcu);
 376
 377         return;
 378 }
 379
 380 /*
 381  * We need to execute ht_destroy outside of RCU read-side critical
 382  * section and outside of call_rcu thread, so we postpone its execution
 383  * using ht_cleanup_push. It is simpler than to change the semantic of
 384  * the many callers of delete_ust_app_session().
 385  */
 386 static
 387 void destroy_channel_rcu(struct rcu_head *head)
 388 {
 389         struct ust_registry_channel *chan =
 390                 caa_container_of(head, struct ust_registry_channel, rcu_head);
 391
 392         if (chan->ht) {
 393                 ht_cleanup_push(chan->ht);
 394         }
 395         free(chan->ctx_fields);
 396         free(chan);
 397 }
 398
 399 /*
 400  * Destroy every element of the registry and free the memory. This does NOT
 401  * free the registry pointer since it might not have been allocated before so
 402  * it's the caller responsability.
 403  */
 404 static void destroy_channel(struct ust_registry_channel *chan)
 405 {
 406         struct lttng_ht_iter iter;
 407         struct ust_registry_event *event;
 408
 409         assert(chan);
 410
 411         rcu_read_lock();
 412         /* Destroy all event associated with this registry. */
 413         cds_lfht_for_each_entry(chan->ht->ht, &iter.iter, event, node.node) {
 414                 /* Delete the node from the ht and free it. */
 415                 ust_registry_destroy_event(chan, event);
 416         }
 417         rcu_read_unlock();
 418         call_rcu(&chan->rcu_head, destroy_channel_rcu);
 419 }
 420
 421 /*
 422  * Initialize registry with default values.
 423  */
 424 int ust_registry_channel_add(struct ust_registry_session *session,
 425                 uint64_t key)
 426 {
 427         int ret = 0;
 428         struct ust_registry_channel *chan;
 429
 430         assert(session);
 431
 432         chan = zmalloc(sizeof(*chan));
 433         if (!chan) {
 434                 PERROR("zmalloc ust registry channel");
 435                 ret = -ENOMEM;
 436                 goto error_alloc;
 437         }
 438
 439         chan->ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 440         if (!chan->ht) {
 441                 ret = -ENOMEM;
 442                 goto error;
 443         }
 444
 445         /* Set custom match function. */
 446         chan->ht->match_fct = ht_match_event;
 447         chan->ht->hash_fct = ht_hash_event;
 448
 449         /*
 450          * Assign a channel ID right now since the event notification comes
 451          * *before* the channel notify so the ID needs to be set at this point so
 452          * the metadata can be dumped for that event.
 453          */
 454         if (ust_registry_is_max_id(session->used_channel_id)) {
 455                 ret = -1;
 456                 goto error;
 457         }
 458         chan->chan_id = ust_registry_get_next_chan_id(session);
 459
 460         rcu_read_lock();
 461         lttng_ht_node_init_u64(&chan->node, key);
 462         lttng_ht_add_unique_u64(session->channels, &chan->node);
 463         rcu_read_unlock();
 464
 465         return 0;
 466
 467 error:
 468         destroy_channel(chan);
 469 error_alloc:
 470         return ret;
 471 }
 472
 473 /*
 474  * Find a channel in the given registry. RCU read side lock MUST be acquired
 475  * before calling this function and as long as the event reference is kept by
 476  * the caller.
 477  *
 478  * On success, the pointer is returned else NULL.
 479  */
 480 struct ust_registry_channel *ust_registry_channel_find(
 481                 struct ust_registry_session *session, uint64_t key)
 482 {
 483         struct lttng_ht_node_u64 *node;
 484         struct lttng_ht_iter iter;
 485         struct ust_registry_channel *chan = NULL;
 486
 487         assert(session);
 488         assert(session->channels);
 489
 490         DBG3("UST registry channel finding key %" PRIu64, key);
 491
 492         lttng_ht_lookup(session->channels, &key, &iter);
 493         node = lttng_ht_iter_get_node_u64(&iter);
 494         if (!node) {
 495                 goto end;
 496         }
 497         chan = caa_container_of(node, struct ust_registry_channel, node);
 498
 499 end:
 500         return chan;
 501 }
 502
 503 /*
 504  * Remove channel using key from registry and free memory.
 505  */
 506 void ust_registry_channel_del_free(struct ust_registry_session *session,
 507                 uint64_t key)
 508 {
 509         struct lttng_ht_iter iter;
 510         struct ust_registry_channel *chan;
 511         int ret;
 512
 513         assert(session);
 514
 515         rcu_read_lock();
 516         chan = ust_registry_channel_find(session, key);
 517         if (!chan) {
 518                 rcu_read_unlock();
 519                 goto end;
 520         }
 521
 522         iter.iter.node = &chan->node.node;
 523         ret = lttng_ht_del(session->channels, &iter);
 524         assert(!ret);
 525         rcu_read_unlock();
 526         destroy_channel(chan);
 527
 528 end:
 529         return;
 530 }
 531
 532 /*
 533  * Initialize registry with default values and set the newly allocated session
 534  * pointer to sessionp.
 535  *
 536  * Return 0 on success and sessionp is set or else return -1 and sessionp is
 537  * kept untouched.
 538  */
 539 int ust_registry_session_init(struct ust_registry_session **sessionp,
 540                 struct ust_app *app,
 541                 uint32_t bits_per_long,
 542                 uint32_t uint8_t_alignment,
 543                 uint32_t uint16_t_alignment,
 544                 uint32_t uint32_t_alignment,
 545                 uint32_t uint64_t_alignment,
 546                 uint32_t long_alignment,
 547                 int byte_order,
 548                 uint32_t major,
 549                 uint32_t minor)
 550 {
 551         int ret;
 552         struct ust_registry_session *session;
 553
 554         assert(sessionp);
 555
 556         session = zmalloc(sizeof(*session));
 557         if (!session) {
 558                 PERROR("zmalloc ust registry session");
 559                 goto error_alloc;
 560         }
 561
 562         pthread_mutex_init(&session->lock, NULL);
 563         session->bits_per_long = bits_per_long;
 564         session->uint8_t_alignment = uint8_t_alignment;
 565         session->uint16_t_alignment = uint16_t_alignment;
 566         session->uint32_t_alignment = uint32_t_alignment;
 567         session->uint64_t_alignment = uint64_t_alignment;
 568         session->long_alignment = long_alignment;
 569         session->byte_order = byte_order;
 570
 571         session->channels = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 572         if (!session->channels) {
 573                 goto error;
 574         }
 575
 576         ret = lttng_uuid_generate(session->uuid);
 577         if (ret) {
 578                 ERR("Failed to generate UST uuid (errno = %d)", ret);
 579                 goto error;
 580         }
 581
 582         pthread_mutex_lock(&session->lock);
 583         ret = ust_metadata_session_statedump(session, app, major, minor);
 584         pthread_mutex_unlock(&session->lock);
 585         if (ret) {
 586                 ERR("Failed to generate session metadata (errno = %d)", ret);
 587                 goto error;
 588         }
 589
 590         *sessionp = session;
 591
 592         return 0;
 593
 594 error:
 595         ust_registry_session_destroy(session);
 596         free(session);
 597 error_alloc:
 598         return -1;
 599 }
 600
 601 /*
 602  * Destroy session registry. This does NOT free the given pointer since it
 603  * might get passed as a reference. The registry lock should NOT be acquired.
 604  */
 605 void ust_registry_session_destroy(struct ust_registry_session *reg)
 606 {
 607         int ret;
 608         struct lttng_ht_iter iter;
 609         struct ust_registry_channel *chan;
 610
 611         assert(reg);
 612
 613         /* On error, EBUSY can be returned if lock. Code flow error. */
 614         ret = pthread_mutex_destroy(&reg->lock);
 615         assert(!ret);
 616
 617         if (reg->channels) {
 618                 rcu_read_lock();
 619                 /* Destroy all event associated with this registry. */
 620                 cds_lfht_for_each_entry(reg->channels->ht, &iter.iter, chan,
 621                                 node.node) {
 622                         /* Delete the node from the ht and free it. */
 623                         ret = lttng_ht_del(reg->channels, &iter);
 624                         assert(!ret);
 625                         destroy_channel(chan);
 626                 }
 627                 rcu_read_unlock();
 628                 ht_cleanup_push(reg->channels);
 629         }
 630
 631         free(reg->metadata);
 632 }