src/common/consumer/consumer-stream.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  * Copyright (C) 2013 - David Goulet <dgoulet@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <assert.h>
  22 #include <inttypes.h>
  23 #include <sys/mman.h>
  24 #include <unistd.h>
  25
  26 #include <common/common.h>
  27 #include <common/index/index.h>
  28 #include <common/kernel-consumer/kernel-consumer.h>
  29 #include <common/relayd/relayd.h>
  30 #include <common/ust-consumer/ust-consumer.h>
  31 #include <common/utils.h>
  32
  33 #include "consumer-stream.h"
  34
  35 /*
  36  * RCU call to free stream. MUST only be used with call_rcu().
  37  */
  38 static void free_stream_rcu(struct rcu_head *head)
  39 {
  40         struct lttng_ht_node_u64 *node =
  41                 caa_container_of(head, struct lttng_ht_node_u64, head);
  42         struct lttng_consumer_stream *stream =
  43                 caa_container_of(node, struct lttng_consumer_stream, node);
  44
  45         pthread_mutex_destroy(&stream->lock);
  46         free(stream);
  47 }
  48
  49 /*
  50  * Close stream on the relayd side. This call can destroy a relayd if the
  51  * conditions are met.
  52  *
  53  * A RCU read side lock MUST be acquired if the relayd object was looked up in
  54  * a hash table before calling this.
  55  */
  56 void consumer_stream_relayd_close(struct lttng_consumer_stream *stream,
  57                 struct consumer_relayd_sock_pair *relayd)
  58 {
  59         int ret;
  60
  61         assert(stream);
  62         assert(relayd);
  63
  64         if (stream->sent_to_relayd) {
  65                 uatomic_dec(&relayd->refcount);
  66                 assert(uatomic_read(&relayd->refcount) >= 0);
  67         }
  68
  69         /* Closing streams requires to lock the control socket. */
  70         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
  71         ret = relayd_send_close_stream(&relayd->control_sock,
  72                         stream->relayd_stream_id,
  73                         stream->next_net_seq_num - 1);
  74         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
  75         if (ret < 0) {
  76                 ERR("Relayd send close stream failed. Cleaning up relayd %" PRIu64 ".", relayd->net_seq_idx);
  77                 lttng_consumer_cleanup_relayd(relayd);
  78         }
  79
  80         /* Both conditions are met, we destroy the relayd. */
  81         if (uatomic_read(&relayd->refcount) == 0 &&
  82                         uatomic_read(&relayd->destroy_flag)) {
  83                 consumer_destroy_relayd(relayd);
  84         }
  85         stream->net_seq_idx = (uint64_t) -1ULL;
  86         stream->sent_to_relayd = 0;
  87 }
  88
  89 /*
  90  * Close stream's file descriptors and, if needed, close stream also on the
  91  * relayd side.
  92  *
  93  * The consumer data lock MUST be acquired.
  94  * The stream lock MUST be acquired.
  95  */
  96 void consumer_stream_close(struct lttng_consumer_stream *stream)
  97 {
  98         int ret;
  99         struct consumer_relayd_sock_pair *relayd;
 100
 101         assert(stream);
 102
 103         switch (consumer_data.type) {
 104         case LTTNG_CONSUMER_KERNEL:
 105                 if (stream->mmap_base != NULL) {
 106                         ret = munmap(stream->mmap_base, stream->mmap_len);
 107                         if (ret != 0) {
 108                                 PERROR("munmap");
 109                         }
 110                 }
 111
 112                 if (stream->wait_fd >= 0) {
 113                         ret = close(stream->wait_fd);
 114                         if (ret) {
 115                                 PERROR("close");
 116                         }
 117                         stream->wait_fd = -1;
 118                 }
 119                 if (stream->chan->output == CONSUMER_CHANNEL_SPLICE) {
 120                         utils_close_pipe(stream->splice_pipe);
 121                 }
 122                 break;
 123         case LTTNG_CONSUMER32_UST:
 124         case LTTNG_CONSUMER64_UST:
 125         {
 126                 /*
 127                  * Special case for the metadata since the wait fd is an internal pipe
 128                  * polled in the metadata thread.
 129                  */
 130                 if (stream->metadata_flag && stream->chan->monitor) {
 131                         int rpipe = stream->ust_metadata_poll_pipe[0];
 132
 133                         /*
 134                          * This will stop the channel timer if one and close the write side
 135                          * of the metadata poll pipe.
 136                          */
 137                         lttng_ustconsumer_close_metadata(stream->chan);
 138                         if (rpipe >= 0) {
 139                                 ret = close(rpipe);
 140                                 if (ret < 0) {
 141                                         PERROR("closing metadata pipe read side");
 142                                 }
 143                                 stream->ust_metadata_poll_pipe[0] = -1;
 144                         }
 145                 }
 146                 break;
 147         }
 148         default:
 149                 ERR("Unknown consumer_data type");
 150                 assert(0);
 151         }
 152
 153         /* Close output fd. Could be a socket or local file at this point. */
 154         if (stream->out_fd >= 0) {
 155                 ret = close(stream->out_fd);
 156                 if (ret) {
 157                         PERROR("close");
 158                 }
 159                 stream->out_fd = -1;
 160         }
 161
 162         if (stream->index_file) {
 163                 lttng_index_file_put(stream->index_file);
 164                 stream->index_file = NULL;
 165         }
 166
 167         /* Check and cleanup relayd if needed. */
 168         rcu_read_lock();
 169         relayd = consumer_find_relayd(stream->net_seq_idx);
 170         if (relayd != NULL) {
 171                 consumer_stream_relayd_close(stream, relayd);
 172         }
 173         rcu_read_unlock();
 174 }
 175
 176 /*
 177  * Delete the stream from all possible hash tables.
 178  *
 179  * The consumer data lock MUST be acquired.
 180  * The stream lock MUST be acquired.
 181  */
 182 void consumer_stream_delete(struct lttng_consumer_stream *stream,
 183                 struct lttng_ht *ht)
 184 {
 185         int ret;
 186         struct lttng_ht_iter iter;
 187
 188         assert(stream);
 189         /* Should NEVER be called not in monitor mode. */
 190         assert(stream->chan->monitor);
 191
 192         rcu_read_lock();
 193
 194         if (ht) {
 195                 iter.iter.node = &stream->node.node;
 196                 ret = lttng_ht_del(ht, &iter);
 197                 assert(!ret);
 198         }
 199
 200         /* Delete from stream per channel ID hash table. */
 201         iter.iter.node = &stream->node_channel_id.node;
 202         /*
 203          * The returned value is of no importance. Even if the node is NOT in the
 204          * hash table, we continue since we may have been called by a code path
 205          * that did not add the stream to a (all) hash table. Same goes for the
 206          * next call ht del call.
 207          */
 208         (void) lttng_ht_del(consumer_data.stream_per_chan_id_ht, &iter);
 209
 210         /* Delete from the global stream list. */
 211         iter.iter.node = &stream->node_session_id.node;
 212         /* See the previous ht del on why we ignore the returned value. */
 213         (void) lttng_ht_del(consumer_data.stream_list_ht, &iter);
 214
 215         rcu_read_unlock();
 216
 217         if (!stream->metadata_flag) {
 218                 /* Decrement the stream count of the global consumer data. */
 219                 assert(consumer_data.stream_count > 0);
 220                 consumer_data.stream_count--;
 221         }
 222 }
 223
 224 /*
 225  * Free the given stream within a RCU call.
 226  */
 227 void consumer_stream_free(struct lttng_consumer_stream *stream)
 228 {
 229         assert(stream);
 230
 231         call_rcu(&stream->node.head, free_stream_rcu);
 232 }
 233
 234 /*
 235  * Destroy the stream's buffers of the tracer.
 236  */
 237 void consumer_stream_destroy_buffers(struct lttng_consumer_stream *stream)
 238 {
 239         assert(stream);
 240
 241         switch (consumer_data.type) {
 242         case LTTNG_CONSUMER_KERNEL:
 243                 break;
 244         case LTTNG_CONSUMER32_UST:
 245         case LTTNG_CONSUMER64_UST:
 246                 lttng_ustconsumer_del_stream(stream);
 247                 break;
 248         default:
 249                 ERR("Unknown consumer_data type");
 250                 assert(0);
 251         }
 252 }
 253
 254 /*
 255  * Destroy and close a already created stream.
 256  */
 257 static void destroy_close_stream(struct lttng_consumer_stream *stream)
 258 {
 259         assert(stream);
 260
 261         DBG("Consumer stream destroy monitored key: %" PRIu64, stream->key);
 262
 263         /* Destroy tracer buffers of the stream. */
 264         consumer_stream_destroy_buffers(stream);
 265         /* Close down everything including the relayd if one. */
 266         consumer_stream_close(stream);
 267 }
 268
 269 /*
 270  * Decrement the stream's channel refcount and if down to 0, return the channel
 271  * pointer so it can be destroyed by the caller or NULL if not.
 272  */
 273 static struct lttng_consumer_channel *unref_channel(
 274                 struct lttng_consumer_stream *stream)
 275 {
 276         struct lttng_consumer_channel *free_chan = NULL;
 277
 278         assert(stream);
 279         assert(stream->chan);
 280
 281         /* Update refcount of channel and see if we need to destroy it. */
 282         if (!uatomic_sub_return(&stream->chan->refcount, 1)
 283                         && !uatomic_read(&stream->chan->nb_init_stream_left)) {
 284                 free_chan = stream->chan;
 285         }
 286
 287         return free_chan;
 288 }
 289
 290 /*
 291  * Destroy a stream completely. This will delete, close and free the stream.
 292  * Once return, the stream is NO longer usable. Its channel may get destroyed
 293  * if conditions are met for a monitored stream.
 294  *
 295  * This MUST be called WITHOUT the consumer data and stream lock acquired if
 296  * the stream is in _monitor_ mode else it does not matter.
 297  */
 298 void consumer_stream_destroy(struct lttng_consumer_stream *stream,
 299                 struct lttng_ht *ht)
 300 {
 301         assert(stream);
 302
 303         /* Stream is in monitor mode. */
 304         if (stream->monitor) {
 305                 struct lttng_consumer_channel *free_chan = NULL;
 306
 307                 /*
 308                  * This means that the stream was successfully removed from the streams
 309                  * list of the channel and sent to the right thread managing this
 310                  * stream thus being globally visible.
 311                  */
 312                 if (stream->globally_visible) {
 313                         pthread_mutex_lock(&consumer_data.lock);
 314                         pthread_mutex_lock(&stream->chan->lock);
 315                         pthread_mutex_lock(&stream->lock);
 316                         /* Remove every reference of the stream in the consumer. */
 317                         consumer_stream_delete(stream, ht);
 318
 319                         destroy_close_stream(stream);
 320
 321                         /* Update channel's refcount of the stream. */
 322                         free_chan = unref_channel(stream);
 323
 324                         /* Indicates that the consumer data state MUST be updated after this. */
 325                         consumer_data.need_update = 1;
 326
 327                         pthread_mutex_unlock(&stream->lock);
 328                         pthread_mutex_unlock(&stream->chan->lock);
 329                         pthread_mutex_unlock(&consumer_data.lock);
 330                 } else {
 331                         /*
 332                          * If the stream is not visible globally, this needs to be done
 333                          * outside of the consumer data lock section.
 334                          */
 335                         free_chan = unref_channel(stream);
 336                 }
 337
 338                 if (free_chan) {
 339                         consumer_del_channel(free_chan);
 340                 }
 341         } else {
 342                 destroy_close_stream(stream);
 343         }
 344
 345         /* Free stream within a RCU call. */
 346         consumer_stream_free(stream);
 347 }
 348
 349 /*
 350  * Write index of a specific stream either on the relayd or local disk.
 351  *
 352  * Return 0 on success or else a negative value.
 353  */
 354 int consumer_stream_write_index(struct lttng_consumer_stream *stream,
 355                 struct ctf_packet_index *element)
 356 {
 357         int ret;
 358
 359         assert(stream);
 360         assert(element);
 361
 362         rcu_read_lock();
 363         if (stream->net_seq_idx != (uint64_t) -1ULL) {
 364                 struct consumer_relayd_sock_pair *relayd;
 365                 relayd = consumer_find_relayd(stream->net_seq_idx);
 366                 if (relayd) {
 367                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 368                         ret = relayd_send_index(&relayd->control_sock, element,
 369                                 stream->relayd_stream_id, stream->next_net_seq_num - 1);
 370                         if (ret < 0) {
 371                                 /*
 372                                  * Communication error with lttng-relayd,
 373                                  * perform cleanup now
 374                                  */
 375                                 ERR("Relayd send index failed. Cleaning up relayd %" PRIu64 ".", relayd->net_seq_idx);
 376                                 lttng_consumer_cleanup_relayd(relayd);
 377                                 ret = -1;
 378                         }
 379                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 380                 } else {
 381                         ERR("Stream %" PRIu64 " relayd ID %" PRIu64 " unknown. Can't write index.",
 382                                         stream->key, stream->net_seq_idx);
 383                         ret = -1;
 384                 }
 385         } else {
 386                 if (lttng_index_file_write(stream->index_file, element)) {
 387                         ret = -1;
 388                 } else {
 389                         ret = 0;
 390                 }
 391         }
 392         if (ret < 0) {
 393                 goto error;
 394         }
 395
 396 error:
 397         rcu_read_unlock();
 398         return ret;
 399 }
 400
 401 /*
 402  * Actually do the metadata sync using the given metadata stream.
 403  *
 404  * Return 0 on success else a negative value. ENODATA can be returned also
 405  * indicating that there is no metadata available for that stream.
 406  */
 407 static int do_sync_metadata(struct lttng_consumer_stream *metadata,
 408                 struct lttng_consumer_local_data *ctx)
 409 {
 410         int ret;
 411
 412         assert(metadata);
 413         assert(metadata->metadata_flag);
 414         assert(ctx);
 415
 416         /*
 417          * In UST, since we have to write the metadata from the cache packet
 418          * by packet, we might need to start this procedure multiple times
 419          * until all the metadata from the cache has been extracted.
 420          */
 421         do {
 422                 /*
 423                  * Steps :
 424                  * - Lock the metadata stream
 425                  * - Check if metadata stream node was deleted before locking.
 426                  *   - if yes, release and return success
 427                  * - Check if new metadata is ready (flush + snapshot pos)
 428                  * - If nothing : release and return.
 429                  * - Lock the metadata_rdv_lock
 430                  * - Unlock the metadata stream
 431                  * - cond_wait on metadata_rdv to wait the wakeup from the
 432                  *   metadata thread
 433                  * - Unlock the metadata_rdv_lock
 434                  */
 435                 pthread_mutex_lock(&metadata->lock);
 436
 437                 /*
 438                  * There is a possibility that we were able to acquire a reference on the
 439                  * stream from the RCU hash table but between then and now, the node might
 440                  * have been deleted just before the lock is acquired. Thus, after locking,
 441                  * we make sure the metadata node has not been deleted which means that the
 442                  * buffers are closed.
 443                  *
 444                  * In that case, there is no need to sync the metadata hence returning a
 445                  * success return code.
 446                  */
 447                 ret = cds_lfht_is_node_deleted(&metadata->node.node);
 448                 if (ret) {
 449                         ret = 0;
 450                         goto end_unlock_mutex;
 451                 }
 452
 453                 switch (ctx->type) {
 454                 case LTTNG_CONSUMER_KERNEL:
 455                         /*
 456                          * Empty the metadata cache and flush the current stream.
 457                          */
 458                         ret = lttng_kconsumer_sync_metadata(metadata);
 459                         break;
 460                 case LTTNG_CONSUMER32_UST:
 461                 case LTTNG_CONSUMER64_UST:
 462                         /*
 463                          * Ask the sessiond if we have new metadata waiting and update the
 464                          * consumer metadata cache.
 465                          */
 466                         ret = lttng_ustconsumer_sync_metadata(ctx, metadata);
 467                         break;
 468                 default:
 469                         assert(0);
 470                         ret = -1;
 471                         break;
 472                 }
 473                 /*
 474                  * Error or no new metadata, we exit here.
 475                  */
 476                 if (ret <= 0 || ret == ENODATA) {
 477                         goto end_unlock_mutex;
 478                 }
 479
 480                 /*
 481                  * At this point, new metadata have been flushed, so we wait on the
 482                  * rendez-vous point for the metadata thread to wake us up when it
 483                  * finishes consuming the metadata and continue execution.
 484                  */
 485
 486                 pthread_mutex_lock(&metadata->metadata_rdv_lock);
 487
 488                 /*
 489                  * Release metadata stream lock so the metadata thread can process it.
 490                  */
 491                 pthread_mutex_unlock(&metadata->lock);
 492
 493                 /*
 494                  * Wait on the rendez-vous point. Once woken up, it means the metadata was
 495                  * consumed and thus synchronization is achieved.
 496                  */
 497                 pthread_cond_wait(&metadata->metadata_rdv, &metadata->metadata_rdv_lock);
 498                 pthread_mutex_unlock(&metadata->metadata_rdv_lock);
 499         } while (ret == EAGAIN);
 500
 501         /* Success */
 502         return 0;
 503
 504 end_unlock_mutex:
 505         pthread_mutex_unlock(&metadata->lock);
 506         return ret;
 507 }
 508
 509 /*
 510  * Synchronize the metadata using a given session ID. A successful acquisition
 511  * of a metadata stream will trigger a request to the session daemon and a
 512  * snapshot so the metadata thread can consume it.
 513  *
 514  * This function call is a rendez-vous point between the metadata thread and
 515  * the data thread.
 516  *
 517  * Return 0 on success or else a negative value.
 518  */
 519 int consumer_stream_sync_metadata(struct lttng_consumer_local_data *ctx,
 520                 uint64_t session_id)
 521 {
 522         int ret;
 523         struct lttng_consumer_stream *stream = NULL;
 524         struct lttng_ht_iter iter;
 525         struct lttng_ht *ht;
 526
 527         assert(ctx);
 528
 529         /* Ease our life a bit. */
 530         ht = consumer_data.stream_list_ht;
 531
 532         rcu_read_lock();
 533
 534         /* Search the metadata associated with the session id of the given stream. */
 535
 536         cds_lfht_for_each_entry_duplicate(ht->ht,
 537                         ht->hash_fct(&session_id, lttng_ht_seed), ht->match_fct,
 538                         &session_id, &iter.iter, stream, node_session_id.node) {
 539                 if (!stream->metadata_flag) {
 540                         continue;
 541                 }
 542
 543                 ret = do_sync_metadata(stream, ctx);
 544                 if (ret < 0) {
 545                         goto end;
 546                 }
 547         }
 548
 549         /*
 550          * Force return code to 0 (success) since ret might be ENODATA for instance
 551          * which is not an error but rather that we should come back.
 552          */
 553         ret = 0;
 554
 555 end:
 556         rcu_read_unlock();
 557         return ret;
 558 }