src/common/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 _GNU_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
  32 #include "consumer-stream.h"
  33
  34 /*
  35  * RCU call to free stream. MUST only be used with call_rcu().
  36  */
  37 static void free_stream_rcu(struct rcu_head *head)
  38 {
  39         struct lttng_ht_node_u64 *node =
  40                 caa_container_of(head, struct lttng_ht_node_u64, head);
  41         struct lttng_consumer_stream *stream =
  42                 caa_container_of(node, struct lttng_consumer_stream, node);
  43
  44         pthread_mutex_destroy(&stream->lock);
  45         free(stream);
  46 }
  47
  48 /*
  49  * Close stream on the relayd side. This call can destroy a relayd if the
  50  * conditions are met.
  51  *
  52  * A RCU read side lock MUST be acquired if the relayd object was looked up in
  53  * a hash table before calling this.
  54  */
  55 void consumer_stream_relayd_close(struct lttng_consumer_stream *stream,
  56                 struct consumer_relayd_sock_pair *relayd)
  57 {
  58         int ret;
  59
  60         assert(stream);
  61         assert(relayd);
  62
  63         if (stream->sent_to_relayd) {
  64                 uatomic_dec(&relayd->refcount);
  65                 assert(uatomic_read(&relayd->refcount) >= 0);
  66         }
  67
  68         /* Closing streams requires to lock the control socket. */
  69         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
  70         ret = relayd_send_close_stream(&relayd->control_sock,
  71                         stream->relayd_stream_id,
  72                         stream->next_net_seq_num - 1);
  73         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
  74         if (ret < 0) {
  75                 DBG("Unable to close stream on the relayd. Continuing");
  76                 /*
  77                  * Continue here. There is nothing we can do for the relayd.
  78                  * Chances are that the relayd has closed the socket so we just
  79                  * continue cleaning up.
  80                  */
  81         }
  82
  83         /* Both conditions are met, we destroy the relayd. */
  84         if (uatomic_read(&relayd->refcount) == 0 &&
  85                         uatomic_read(&relayd->destroy_flag)) {
  86                 consumer_destroy_relayd(relayd);
  87         }
  88         stream->net_seq_idx = (uint64_t) -1ULL;
  89         stream->sent_to_relayd = 0;
  90 }
  91
  92 /*
  93  * Close stream's file descriptors and, if needed, close stream also on the
  94  * relayd side.
  95  *
  96  * The consumer data lock MUST be acquired.
  97  * The stream lock MUST be acquired.
  98  */
  99 void consumer_stream_close(struct lttng_consumer_stream *stream)
 100 {
 101         int ret;
 102         struct consumer_relayd_sock_pair *relayd;
 103
 104         assert(stream);
 105
 106         switch (consumer_data.type) {
 107         case LTTNG_CONSUMER_KERNEL:
 108                 if (stream->mmap_base != NULL) {
 109                         ret = munmap(stream->mmap_base, stream->mmap_len);
 110                         if (ret != 0) {
 111                                 PERROR("munmap");
 112                         }
 113                 }
 114
 115                 if (stream->wait_fd >= 0) {
 116                         ret = close(stream->wait_fd);
 117                         if (ret) {
 118                                 PERROR("close");
 119                         }
 120                         stream->wait_fd = -1;
 121                 }
 122                 break;
 123         case LTTNG_CONSUMER32_UST:
 124         case LTTNG_CONSUMER64_UST:
 125                 break;
 126         default:
 127                 ERR("Unknown consumer_data type");
 128                 assert(0);
 129         }
 130
 131         /* Close output fd. Could be a socket or local file at this point. */
 132         if (stream->out_fd >= 0) {
 133                 ret = close(stream->out_fd);
 134                 if (ret) {
 135                         PERROR("close");
 136                 }
 137                 stream->out_fd = -1;
 138         }
 139
 140         if (stream->index_fd >= 0) {
 141                 ret = close(stream->index_fd);
 142                 if (ret) {
 143                         PERROR("close stream index_fd");
 144                 }
 145                 stream->index_fd = -1;
 146         }
 147
 148         /* Check and cleanup relayd if needed. */
 149         rcu_read_lock();
 150         relayd = consumer_find_relayd(stream->net_seq_idx);
 151         if (relayd != NULL) {
 152                 consumer_stream_relayd_close(stream, relayd);
 153         }
 154         rcu_read_unlock();
 155 }
 156
 157 /*
 158  * Delete the stream from all possible hash tables.
 159  *
 160  * The consumer data lock MUST be acquired.
 161  * The stream lock MUST be acquired.
 162  */
 163 void consumer_stream_delete(struct lttng_consumer_stream *stream,
 164                 struct lttng_ht *ht)
 165 {
 166         int ret;
 167         struct lttng_ht_iter iter;
 168
 169         assert(stream);
 170         /* Should NEVER be called not in monitor mode. */
 171         assert(stream->chan->monitor);
 172
 173         rcu_read_lock();
 174
 175         if (ht) {
 176                 iter.iter.node = &stream->node.node;
 177                 ret = lttng_ht_del(ht, &iter);
 178                 assert(!ret);
 179         }
 180
 181         /* Delete from stream per channel ID hash table. */
 182         iter.iter.node = &stream->node_channel_id.node;
 183         /*
 184          * The returned value is of no importance. Even if the node is NOT in the
 185          * hash table, we continue since we may have been called by a code path
 186          * that did not add the stream to a (all) hash table. Same goes for the
 187          * next call ht del call.
 188          */
 189         (void) lttng_ht_del(consumer_data.stream_per_chan_id_ht, &iter);
 190
 191         /* Delete from the global stream list. */
 192         iter.iter.node = &stream->node_session_id.node;
 193         /* See the previous ht del on why we ignore the returned value. */
 194         (void) lttng_ht_del(consumer_data.stream_list_ht, &iter);
 195
 196         rcu_read_unlock();
 197
 198         /* Decrement the stream count of the global consumer data. */
 199         assert(consumer_data.stream_count > 0);
 200         consumer_data.stream_count--;
 201 }
 202
 203 /*
 204  * Free the given stream within a RCU call.
 205  */
 206 void consumer_stream_free(struct lttng_consumer_stream *stream)
 207 {
 208         assert(stream);
 209
 210         call_rcu(&stream->node.head, free_stream_rcu);
 211 }
 212
 213 /*
 214  * Destroy the stream's buffers of the tracer.
 215  */
 216 void consumer_stream_destroy_buffers(struct lttng_consumer_stream *stream)
 217 {
 218         assert(stream);
 219
 220         switch (consumer_data.type) {
 221         case LTTNG_CONSUMER_KERNEL:
 222                 break;
 223         case LTTNG_CONSUMER32_UST:
 224         case LTTNG_CONSUMER64_UST:
 225                 lttng_ustconsumer_del_stream(stream);
 226                 break;
 227         default:
 228                 ERR("Unknown consumer_data type");
 229                 assert(0);
 230         }
 231 }
 232
 233 /*
 234  * Destroy and close a already created stream.
 235  */
 236 static void destroy_close_stream(struct lttng_consumer_stream *stream)
 237 {
 238         assert(stream);
 239
 240         DBG("Consumer stream destroy monitored key: %" PRIu64, stream->key);
 241
 242         /* Destroy tracer buffers of the stream. */
 243         consumer_stream_destroy_buffers(stream);
 244         /* Close down everything including the relayd if one. */
 245         consumer_stream_close(stream);
 246 }
 247
 248 /*
 249  * Decrement the stream's channel refcount and if down to 0, return the channel
 250  * pointer so it can be destroyed by the caller or NULL if not.
 251  */
 252 static struct lttng_consumer_channel *unref_channel(
 253                 struct lttng_consumer_stream *stream)
 254 {
 255         struct lttng_consumer_channel *free_chan = NULL;
 256
 257         assert(stream);
 258         assert(stream->chan);
 259
 260         /* Update refcount of channel and see if we need to destroy it. */
 261         if (!uatomic_sub_return(&stream->chan->refcount, 1)
 262                         && !uatomic_read(&stream->chan->nb_init_stream_left)) {
 263                 free_chan = stream->chan;
 264         }
 265
 266         return free_chan;
 267 }
 268
 269 /*
 270  * Destroy a stream completely. This will delete, close and free the stream.
 271  * Once return, the stream is NO longer usable. Its channel may get destroyed
 272  * if conditions are met for a monitored stream.
 273  *
 274  * This MUST be called WITHOUT the consumer data and stream lock acquired if
 275  * the stream is in _monitor_ mode else it does not matter.
 276  */
 277 void consumer_stream_destroy(struct lttng_consumer_stream *stream,
 278                 struct lttng_ht *ht)
 279 {
 280         assert(stream);
 281
 282         /* Stream is in monitor mode. */
 283         if (stream->monitor) {
 284                 struct lttng_consumer_channel *free_chan = NULL;
 285
 286                 /*
 287                  * This means that the stream was successfully removed from the streams
 288                  * list of the channel and sent to the right thread managing this
 289                  * stream thus being globally visible.
 290                  */
 291                 if (stream->globally_visible) {
 292                         pthread_mutex_lock(&consumer_data.lock);
 293                         pthread_mutex_lock(&stream->chan->lock);
 294                         pthread_mutex_lock(&stream->lock);
 295                         /* Remove every reference of the stream in the consumer. */
 296                         consumer_stream_delete(stream, ht);
 297
 298                         destroy_close_stream(stream);
 299
 300                         /* Update channel's refcount of the stream. */
 301                         free_chan = unref_channel(stream);
 302
 303                         /* Indicates that the consumer data state MUST be updated after this. */
 304                         consumer_data.need_update = 1;
 305
 306                         pthread_mutex_unlock(&stream->lock);
 307                         pthread_mutex_unlock(&stream->chan->lock);
 308                         pthread_mutex_unlock(&consumer_data.lock);
 309                 } else {
 310                         /*
 311                          * If the stream is not visible globally, this needs to be done
 312                          * outside of the consumer data lock section.
 313                          */
 314                         free_chan = unref_channel(stream);
 315                 }
 316
 317                 if (free_chan) {
 318                         consumer_del_channel(free_chan);
 319                 }
 320         } else {
 321                 destroy_close_stream(stream);
 322         }
 323
 324         /* Free stream within a RCU call. */
 325         consumer_stream_free(stream);
 326 }
 327
 328 /*
 329  * Write index of a specific stream either on the relayd or local disk.
 330  *
 331  * Return 0 on success or else a negative value.
 332  */
 333 int consumer_stream_write_index(struct lttng_consumer_stream *stream,
 334                 struct lttng_packet_index *index)
 335 {
 336         int ret;
 337         struct consumer_relayd_sock_pair *relayd;
 338
 339         assert(stream);
 340         assert(index);
 341
 342         rcu_read_lock();
 343         relayd = consumer_find_relayd(stream->net_seq_idx);
 344         if (relayd) {
 345                 ret = relayd_send_index(&relayd->control_sock, index,
 346                                 stream->relayd_stream_id, stream->next_net_seq_num - 1);
 347         } else {
 348                 ret = index_write(stream->index_fd, index,
 349                                 sizeof(struct lttng_packet_index));
 350         }
 351         if (ret < 0) {
 352                 goto error;
 353         }
 354
 355 error:
 356         rcu_read_unlock();
 357         return ret;
 358 }
 359
 360 /*
 361  * Synchronize the metadata using a given session ID. A successful acquisition
 362  * of a metadata stream will trigger a request to the session daemon and a
 363  * snapshot so the metadata thread can consume it.
 364  *
 365  * This function call is a rendez-vous point between the metadata thread and
 366  * the data thread.
 367  *
 368  * Return 0 on success or else a negative value.
 369  */
 370 int consumer_stream_sync_metadata(struct lttng_consumer_local_data *ctx,
 371                 uint64_t session_id)
 372 {
 373         int ret;
 374         struct lttng_consumer_stream *metadata = NULL, *stream = NULL;
 375         struct lttng_ht_iter iter;
 376         struct lttng_ht *ht;
 377
 378         assert(ctx);
 379
 380         /* Ease our life a bit. */
 381         ht = consumer_data.stream_list_ht;
 382
 383         rcu_read_lock();
 384
 385         /* Search the metadata associated with the session id of the given stream. */
 386
 387         cds_lfht_for_each_entry_duplicate(ht->ht,
 388                         ht->hash_fct(&session_id, lttng_ht_seed), ht->match_fct,
 389                         &session_id, &iter.iter, stream, node_session_id.node) {
 390                 if (stream->metadata_flag) {
 391                         metadata = stream;
 392                         break;
 393                 }
 394         }
 395         if (!metadata) {
 396                 ret = 0;
 397                 goto end_unlock_rcu;
 398         }
 399
 400         /*
 401          * In UST, since we have to write the metadata from the cache packet
 402          * by packet, we might need to start this procedure multiple times
 403          * until all the metadata from the cache has been extracted.
 404          */
 405         do {
 406                 /*
 407                  * Steps :
 408                  * - Lock the metadata stream
 409                  * - Check if metadata stream node was deleted before locking.
 410                  *   - if yes, release and return success
 411                  * - Check if new metadata is ready (flush + snapshot pos)
 412                  * - If nothing : release and return.
 413                  * - Lock the metadata_rdv_lock
 414                  * - Unlock the metadata stream
 415                  * - cond_wait on metadata_rdv to wait the wakeup from the
 416                  *   metadata thread
 417                  * - Unlock the metadata_rdv_lock
 418                  */
 419                 pthread_mutex_lock(&metadata->lock);
 420
 421                 /*
 422                  * There is a possibility that we were able to acquire a reference on the
 423                  * stream from the RCU hash table but between then and now, the node might
 424                  * have been deleted just before the lock is acquired. Thus, after locking,
 425                  * we make sure the metadata node has not been deleted which means that the
 426                  * buffers are closed.
 427                  *
 428                  * In that case, there is no need to sync the metadata hence returning a
 429                  * success return code.
 430                  */
 431                 ret = cds_lfht_is_node_deleted(&metadata->node.node);
 432                 if (ret) {
 433                         ret = 0;
 434                         goto end_unlock_mutex;
 435                 }
 436
 437                 switch (ctx->type) {
 438                 case LTTNG_CONSUMER_KERNEL:
 439                         /*
 440                          * Empty the metadata cache and flush the current stream.
 441                          */
 442                         ret = lttng_kconsumer_sync_metadata(metadata);
 443                         break;
 444                 case LTTNG_CONSUMER32_UST:
 445                 case LTTNG_CONSUMER64_UST:
 446                         /*
 447                          * Ask the sessiond if we have new metadata waiting and update the
 448                          * consumer metadata cache.
 449                          */
 450                         ret = lttng_ustconsumer_sync_metadata(ctx, metadata);
 451                         break;
 452                 default:
 453                         assert(0);
 454                         ret = -1;
 455                         break;
 456                 }
 457                 /*
 458                  * Error or no new metadata, we exit here.
 459                  */
 460                 if (ret <= 0 || ret == ENODATA) {
 461                         goto end_unlock_mutex;
 462                 }
 463
 464                 /*
 465                  * At this point, new metadata have been flushed, so we wait on the
 466                  * rendez-vous point for the metadata thread to wake us up when it
 467                  * finishes consuming the metadata and continue execution.
 468                  */
 469
 470                 pthread_mutex_lock(&metadata->metadata_rdv_lock);
 471
 472                 /*
 473                  * Release metadata stream lock so the metadata thread can process it.
 474                  */
 475                 pthread_mutex_unlock(&metadata->lock);
 476
 477                 /*
 478                  * Wait on the rendez-vous point. Once woken up, it means the metadata was
 479                  * consumed and thus synchronization is achieved.
 480                  */
 481                 pthread_cond_wait(&metadata->metadata_rdv, &metadata->metadata_rdv_lock);
 482                 pthread_mutex_unlock(&metadata->metadata_rdv_lock);
 483         } while (ret == EAGAIN);
 484
 485         ret = 0;
 486         goto end_unlock_rcu;
 487
 488 end_unlock_mutex:
 489         pthread_mutex_unlock(&metadata->lock);
 490 end_unlock_rcu:
 491         rcu_read_unlock();
 492         return ret;
 493 }