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