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