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