src/common/ust-consumer/ust-consumer.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <assert.h>
  21 #include <lttng/ust-ctl.h>
  22 #include <poll.h>
  23 #include <pthread.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/mman.h>
  27 #include <sys/socket.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <inttypes.h>
  31 #include <unistd.h>
  32 #include <urcu/list.h>
  33 #include <signal.h>
  34
  35 #include <common/common.h>
  36 #include <common/sessiond-comm/sessiond-comm.h>
  37 #include <common/relayd/relayd.h>
  38 #include <common/compat/fcntl.h>
  39 #include <common/consumer-metadata-cache.h>
  40 #include <common/consumer-timer.h>
  41 #include <common/utils.h>
  42
  43 #include "ust-consumer.h"
  44
  45 extern struct lttng_consumer_global_data consumer_data;
  46 extern int consumer_poll_timeout;
  47 extern volatile int consumer_quit;
  48
  49 /*
  50  * Free channel object and all streams associated with it. This MUST be used
  51  * only and only if the channel has _NEVER_ been added to the global channel
  52  * hash table.
  53  */
  54 static void destroy_channel(struct lttng_consumer_channel *channel)
  55 {
  56         struct lttng_consumer_stream *stream, *stmp;
  57
  58         assert(channel);
  59
  60         DBG("UST consumer cleaning stream list");
  61
  62         cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
  63                         send_node) {
  64                 cds_list_del(&stream->send_node);
  65                 ustctl_destroy_stream(stream->ustream);
  66                 free(stream);
  67         }
  68
  69         /*
  70          * If a channel is available meaning that was created before the streams
  71          * were, delete it.
  72          */
  73         if (channel->uchan) {
  74                 lttng_ustconsumer_del_channel(channel);
  75         }
  76         free(channel);
  77 }
  78
  79 /*
  80  * Add channel to internal consumer state.
  81  *
  82  * Returns 0 on success or else a negative value.
  83  */
  84 static int add_channel(struct lttng_consumer_channel *channel,
  85                 struct lttng_consumer_local_data *ctx)
  86 {
  87         int ret = 0;
  88
  89         assert(channel);
  90         assert(ctx);
  91
  92         if (ctx->on_recv_channel != NULL) {
  93                 ret = ctx->on_recv_channel(channel);
  94                 if (ret == 0) {
  95                         ret = consumer_add_channel(channel, ctx);
  96                 } else if (ret < 0) {
  97                         /* Most likely an ENOMEM. */
  98                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
  99                         goto error;
 100                 }
 101         } else {
 102                 ret = consumer_add_channel(channel, ctx);
 103         }
 104
 105         DBG("UST consumer channel added (key: %" PRIu64 ")", channel->key);
 106
 107 error:
 108         return ret;
 109 }
 110
 111 /*
 112  * Allocate and return a consumer channel object.
 113  */
 114 static struct lttng_consumer_channel *allocate_channel(uint64_t session_id,
 115                 const char *pathname, const char *name, uid_t uid, gid_t gid,
 116                 int relayd_id, uint64_t key, enum lttng_event_output output,
 117                 uint64_t tracefile_size, uint64_t tracefile_count)
 118 {
 119         assert(pathname);
 120         assert(name);
 121
 122         return consumer_allocate_channel(key, session_id, pathname, name, uid, gid,
 123                         relayd_id, output, tracefile_size, tracefile_count);
 124 }
 125
 126 /*
 127  * Allocate and return a consumer stream object. If _alloc_ret is not NULL, the
 128  * error value if applicable is set in it else it is kept untouched.
 129  *
 130  * Return NULL on error else the newly allocated stream object.
 131  */
 132 static struct lttng_consumer_stream *allocate_stream(int cpu, int key,
 133                 struct lttng_consumer_channel *channel,
 134                 struct lttng_consumer_local_data *ctx, int *_alloc_ret)
 135 {
 136         int alloc_ret;
 137         struct lttng_consumer_stream *stream = NULL;
 138
 139         assert(channel);
 140         assert(ctx);
 141
 142         stream = consumer_allocate_stream(channel->key,
 143                         key,
 144                         LTTNG_CONSUMER_ACTIVE_STREAM,
 145                         channel->name,
 146                         channel->uid,
 147                         channel->gid,
 148                         channel->relayd_id,
 149                         channel->session_id,
 150                         cpu,
 151                         &alloc_ret,
 152                         channel->type);
 153         if (stream == NULL) {
 154                 switch (alloc_ret) {
 155                 case -ENOENT:
 156                         /*
 157                          * We could not find the channel. Can happen if cpu hotplug
 158                          * happens while tearing down.
 159                          */
 160                         DBG3("Could not find channel");
 161                         break;
 162                 case -ENOMEM:
 163                 case -EINVAL:
 164                 default:
 165                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 166                         break;
 167                 }
 168                 goto error;
 169         }
 170
 171         stream->chan = channel;
 172
 173 error:
 174         if (_alloc_ret) {
 175                 *_alloc_ret = alloc_ret;
 176         }
 177         return stream;
 178 }
 179
 180 /*
 181  * Send the given stream pointer to the corresponding thread.
 182  *
 183  * Returns 0 on success else a negative value.
 184  */
 185 static int send_stream_to_thread(struct lttng_consumer_stream *stream,
 186                 struct lttng_consumer_local_data *ctx)
 187 {
 188         int ret, stream_pipe;
 189
 190         /* Get the right pipe where the stream will be sent. */
 191         if (stream->metadata_flag) {
 192                 stream_pipe = ctx->consumer_metadata_pipe[1];
 193         } else {
 194                 stream_pipe = ctx->consumer_data_pipe[1];
 195         }
 196
 197         do {
 198                 ret = write(stream_pipe, &stream, sizeof(stream));
 199         } while (ret < 0 && errno == EINTR);
 200         if (ret < 0) {
 201                 PERROR("Consumer write %s stream to pipe %d",
 202                                 stream->metadata_flag ? "metadata" : "data", stream_pipe);
 203         }
 204
 205         return ret;
 206 }
 207
 208 /*
 209  * Search for a relayd object related to the stream. If found, send the stream
 210  * to the relayd.
 211  *
 212  * On success, returns 0 else a negative value.
 213  */
 214 static int send_stream_to_relayd(struct lttng_consumer_stream *stream)
 215 {
 216         int ret = 0;
 217         struct consumer_relayd_sock_pair *relayd;
 218
 219         assert(stream);
 220
 221         relayd = consumer_find_relayd(stream->net_seq_idx);
 222         if (relayd != NULL) {
 223                 pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 224                 /* Add stream on the relayd */
 225                 ret = relayd_add_stream(&relayd->control_sock, stream->name,
 226                                 stream->chan->pathname, &stream->relayd_stream_id,
 227                                 stream->chan->tracefile_size,
 228                                 stream->chan->tracefile_count);
 229                 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 230                 if (ret < 0) {
 231                         goto error;
 232                 }
 233         } else if (stream->net_seq_idx != (uint64_t) -1ULL) {
 234                 ERR("Network sequence index %" PRIu64 " unknown. Not adding stream.",
 235                                 stream->net_seq_idx);
 236                 ret = -1;
 237                 goto error;
 238         }
 239
 240 error:
 241         return ret;
 242 }
 243
 244 /*
 245  * Create streams for the given channel using liblttng-ust-ctl.
 246  *
 247  * Return 0 on success else a negative value.
 248  */
 249 static int create_ust_streams(struct lttng_consumer_channel *channel,
 250                 struct lttng_consumer_local_data *ctx)
 251 {
 252         int ret, cpu = 0;
 253         struct ustctl_consumer_stream *ustream;
 254         struct lttng_consumer_stream *stream;
 255
 256         assert(channel);
 257         assert(ctx);
 258
 259         /*
 260          * While a stream is available from ustctl. When NULL is returned, we've
 261          * reached the end of the possible stream for the channel.
 262          */
 263         while ((ustream = ustctl_create_stream(channel->uchan, cpu))) {
 264                 int wait_fd;
 265
 266                 wait_fd = ustctl_stream_get_wait_fd(ustream);
 267
 268                 /* Allocate consumer stream object. */
 269                 stream = allocate_stream(cpu, wait_fd, channel, ctx, &ret);
 270                 if (!stream) {
 271                         goto error_alloc;
 272                 }
 273                 stream->ustream = ustream;
 274                 /*
 275                  * Store it so we can save multiple function calls afterwards since
 276                  * this value is used heavily in the stream threads. This is UST
 277                  * specific so this is why it's done after allocation.
 278                  */
 279                 stream->wait_fd = wait_fd;
 280
 281                 /*
 282                  * Order is important this is why a list is used. On error, the caller
 283                  * should clean this list.
 284                  */
 285                 cds_list_add_tail(&stream->send_node, &channel->streams.head);
 286
 287                 ret = ustctl_get_max_subbuf_size(stream->ustream,
 288                                 &stream->max_sb_size);
 289                 if (ret < 0) {
 290                         ERR("ustctl_get_max_subbuf_size failed for stream %s",
 291                                         stream->name);
 292                         goto error;
 293                 }
 294
 295                 /* Do actions once stream has been received. */
 296                 if (ctx->on_recv_stream) {
 297                         ret = ctx->on_recv_stream(stream);
 298                         if (ret < 0) {
 299                                 goto error;
 300                         }
 301                 }
 302
 303                 DBG("UST consumer add stream %s (key: %" PRIu64 ") with relayd id %" PRIu64,
 304                                 stream->name, stream->key, stream->relayd_stream_id);
 305
 306                 /* Set next CPU stream. */
 307                 channel->streams.count = ++cpu;
 308
 309                 /* Keep stream reference when creating metadata. */
 310                 if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA) {
 311                         channel->metadata_stream = stream;
 312                 }
 313         }
 314
 315         return 0;
 316
 317 error:
 318 error_alloc:
 319         return ret;
 320 }
 321
 322 /*
 323  * Create an UST channel with the given attributes and send it to the session
 324  * daemon using the ust ctl API.
 325  *
 326  * Return 0 on success or else a negative value.
 327  */
 328 static int create_ust_channel(struct ustctl_consumer_channel_attr *attr,
 329                 struct ustctl_consumer_channel **chanp)
 330 {
 331         int ret;
 332         struct ustctl_consumer_channel *channel;
 333
 334         assert(attr);
 335         assert(chanp);
 336
 337         DBG3("Creating channel to ustctl with attr: [overwrite: %d, "
 338                         "subbuf_size: %" PRIu64 ", num_subbuf: %" PRIu64 ", "
 339                         "switch_timer_interval: %u, read_timer_interval: %u, "
 340                         "output: %d, type: %d", attr->overwrite, attr->subbuf_size,
 341                         attr->num_subbuf, attr->switch_timer_interval,
 342                         attr->read_timer_interval, attr->output, attr->type);
 343
 344         channel = ustctl_create_channel(attr);
 345         if (!channel) {
 346                 ret = -1;
 347                 goto error_create;
 348         }
 349
 350         *chanp = channel;
 351
 352         return 0;
 353
 354 error_create:
 355         return ret;
 356 }
 357
 358 /*
 359  * Send a single given stream to the session daemon using the sock.
 360  *
 361  * Return 0 on success else a negative value.
 362  */
 363 static int send_sessiond_stream(int sock, struct lttng_consumer_stream *stream)
 364 {
 365         int ret;
 366
 367         assert(stream);
 368         assert(sock >= 0);
 369
 370         DBG2("UST consumer sending stream %" PRIu64 " to sessiond", stream->key);
 371
 372         /* Send stream to session daemon. */
 373         ret = ustctl_send_stream_to_sessiond(sock, stream->ustream);
 374         if (ret < 0) {
 375                 goto error;
 376         }
 377
 378 error:
 379         return ret;
 380 }
 381
 382 /*
 383  * Send channel to sessiond.
 384  *
 385  * Return 0 on success or else a negative value.
 386  */
 387 static int send_sessiond_channel(int sock,
 388                 struct lttng_consumer_channel *channel,
 389                 struct lttng_consumer_local_data *ctx, int *relayd_error)
 390 {
 391         int ret;
 392         struct lttng_consumer_stream *stream;
 393
 394         assert(channel);
 395         assert(ctx);
 396         assert(sock >= 0);
 397
 398         DBG("UST consumer sending channel %s to sessiond", channel->name);
 399
 400         /* Send channel to sessiond. */
 401         ret = ustctl_send_channel_to_sessiond(sock, channel->uchan);
 402         if (ret < 0) {
 403                 goto error;
 404         }
 405
 406         ret = ustctl_channel_close_wakeup_fd(channel->uchan);
 407         if (ret < 0) {
 408                 goto error;
 409         }
 410
 411         /* The channel was sent successfully to the sessiond at this point. */
 412         cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
 413                 /* Try to send the stream to the relayd if one is available. */
 414                 ret = send_stream_to_relayd(stream);
 415                 if (ret < 0) {
 416                         /*
 417                          * Flag that the relayd was the problem here probably due to a
 418                          * communicaton error on the socket.
 419                          */
 420                         if (relayd_error) {
 421                                 *relayd_error = 1;
 422                         }
 423                         goto error;
 424                 }
 425
 426                 /* Send stream to session daemon. */
 427                 ret = send_sessiond_stream(sock, stream);
 428                 if (ret < 0) {
 429                         goto error;
 430                 }
 431         }
 432
 433         /* Tell sessiond there is no more stream. */
 434         ret = ustctl_send_stream_to_sessiond(sock, NULL);
 435         if (ret < 0) {
 436                 goto error;
 437         }
 438
 439         DBG("UST consumer NULL stream sent to sessiond");
 440
 441         return 0;
 442
 443 error:
 444         return ret;
 445 }
 446
 447 /*
 448  * Creates a channel and streams and add the channel it to the channel internal
 449  * state. The created stream must ONLY be sent once the GET_CHANNEL command is
 450  * received.
 451  *
 452  * Return 0 on success or else, a negative value is returned and the channel
 453  * MUST be destroyed by consumer_del_channel().
 454  */
 455 static int ask_channel(struct lttng_consumer_local_data *ctx, int sock,
 456                 struct lttng_consumer_channel *channel,
 457                 struct ustctl_consumer_channel_attr *attr)
 458 {
 459         int ret;
 460
 461         assert(ctx);
 462         assert(channel);
 463         assert(attr);
 464
 465         /*
 466          * This value is still used by the kernel consumer since for the kernel,
 467          * the stream ownership is not IN the consumer so we need to have the
 468          * number of left stream that needs to be initialized so we can know when
 469          * to delete the channel (see consumer.c).
 470          *
 471          * As for the user space tracer now, the consumer creates and sends the
 472          * stream to the session daemon which only sends them to the application
 473          * once every stream of a channel is received making this value useless
 474          * because we they will be added to the poll thread before the application
 475          * receives them. This ensures that a stream can not hang up during
 476          * initilization of a channel.
 477          */
 478         channel->nb_init_stream_left = 0;
 479
 480         /* The reply msg status is handled in the following call. */
 481         ret = create_ust_channel(attr, &channel->uchan);
 482         if (ret < 0) {
 483                 goto error;
 484         }
 485
 486         channel->wait_fd = ustctl_channel_get_wait_fd(channel->uchan);
 487
 488         if (ret < 0) {
 489                 goto error;
 490         }
 491
 492         /* Open all streams for this channel. */
 493         ret = create_ust_streams(channel, ctx);
 494         if (ret < 0) {
 495                 goto error;
 496         }
 497
 498 error:
 499         return ret;
 500 }
 501
 502 /*
 503  * Send all stream of a channel to the right thread handling it.
 504  *
 505  * On error, return a negative value else 0 on success.
 506  */
 507 static int send_streams_to_thread(struct lttng_consumer_channel *channel,
 508                 struct lttng_consumer_local_data *ctx)
 509 {
 510         int ret = 0;
 511         struct lttng_consumer_stream *stream, *stmp;
 512
 513         assert(channel);
 514         assert(ctx);
 515
 516         /* Send streams to the corresponding thread. */
 517         cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
 518                         send_node) {
 519                 /* Sending the stream to the thread. */
 520                 ret = send_stream_to_thread(stream, ctx);
 521                 if (ret < 0) {
 522                         /*
 523                          * If we are unable to send the stream to the thread, there is
 524                          * a big problem so just stop everything.
 525                          */
 526                         goto error;
 527                 }
 528
 529                 /* Remove node from the channel stream list. */
 530                 cds_list_del(&stream->send_node);
 531         }
 532
 533 error:
 534         return ret;
 535 }
 536
 537 /*
 538  * Write metadata to the given channel using ustctl to convert the string to
 539  * the ringbuffer.
 540  * Called only from consumer_metadata_cache_write.
 541  * The metadata cache lock MUST be acquired to write in the cache.
 542  *
 543  * Return 0 on success else a negative value.
 544  */
 545 int lttng_ustconsumer_push_metadata(struct lttng_consumer_channel *metadata,
 546                 const char *metadata_str, uint64_t target_offset, uint64_t len)
 547 {
 548         int ret;
 549
 550         assert(metadata);
 551         assert(metadata_str);
 552
 553         DBG("UST consumer writing metadata to channel %s", metadata->name);
 554
 555         assert(target_offset <= metadata->metadata_cache->max_offset);
 556         ret = ustctl_write_metadata_to_channel(metadata->uchan,
 557                         metadata_str + target_offset, len);
 558         if (ret < 0) {
 559                 ERR("ustctl write metadata fail with ret %d, len %" PRIu64, ret, len);
 560                 goto error;
 561         }
 562
 563         ustctl_flush_buffer(metadata->metadata_stream->ustream, 1);
 564
 565 error:
 566         return ret;
 567 }
 568
 569 /*
 570  * Flush channel's streams using the given key to retrieve the channel.
 571  *
 572  * Return 0 on success else an LTTng error code.
 573  */
 574 static int flush_channel(uint64_t chan_key)
 575 {
 576         int ret = 0;
 577         struct lttng_consumer_channel *channel;
 578         struct lttng_consumer_stream *stream;
 579         struct lttng_ht *ht;
 580         struct lttng_ht_iter iter;
 581
 582         DBG("UST consumer flush channel key %" PRIu64, chan_key);
 583
 584         channel = consumer_find_channel(chan_key);
 585         if (!channel) {
 586                 ERR("UST consumer flush channel %" PRIu64 " not found", chan_key);
 587                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 588                 goto error;
 589         }
 590
 591         ht = consumer_data.stream_per_chan_id_ht;
 592
 593         /* For each stream of the channel id, flush it. */
 594         rcu_read_lock();
 595         cds_lfht_for_each_entry_duplicate(ht->ht,
 596                         ht->hash_fct(&channel->key, lttng_ht_seed), ht->match_fct,
 597                         &channel->key, &iter.iter, stream, node_channel_id.node) {
 598                         ustctl_flush_buffer(stream->ustream, 1);
 599         }
 600         rcu_read_unlock();
 601
 602 error:
 603         return ret;
 604 }
 605
 606 /*
 607  * Close metadata stream wakeup_fd using the given key to retrieve the channel.
 608  *
 609  * Return 0 on success else an LTTng error code.
 610  */
 611 static int close_metadata(uint64_t chan_key)
 612 {
 613         int ret;
 614         struct lttng_consumer_channel *channel;
 615
 616         DBG("UST consumer close metadata key %" PRIu64, chan_key);
 617
 618         channel = consumer_find_channel(chan_key);
 619         if (!channel) {
 620                 ERR("UST consumer close metadata %" PRIu64 " not found", chan_key);
 621                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 622                 goto error;
 623         }
 624
 625         ret = ustctl_stream_close_wakeup_fd(channel->metadata_stream->ustream);
 626         if (ret < 0) {
 627                 ERR("UST consumer unable to close fd of metadata (ret: %d)", ret);
 628                 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
 629                 goto error;
 630         }
 631         if (channel->switch_timer_enabled == 1) {
 632                 DBG("Deleting timer on metadata channel");
 633                 consumer_timer_switch_stop(channel);
 634         }
 635         consumer_metadata_cache_destroy(channel);
 636
 637 error:
 638         return ret;
 639 }
 640
 641 /*
 642  * RCU read side lock MUST be acquired before calling this function.
 643  *
 644  * Return 0 on success else an LTTng error code.
 645  */
 646 static int setup_metadata(struct lttng_consumer_local_data *ctx, uint64_t key)
 647 {
 648         int ret;
 649         struct lttng_consumer_channel *metadata;
 650
 651         DBG("UST consumer setup metadata key %" PRIu64, key);
 652
 653         metadata = consumer_find_channel(key);
 654         if (!metadata) {
 655                 ERR("UST consumer push metadata %" PRIu64 " not found", key);
 656                 ret = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 657                 goto error;
 658         }
 659
 660         /*
 661          * Send metadata stream to relayd if one available. Availability is
 662          * known if the stream is still in the list of the channel.
 663          */
 664         if (cds_list_empty(&metadata->streams.head)) {
 665                 ERR("Metadata channel key %" PRIu64 ", no stream available.", key);
 666                 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
 667                 goto error;
 668         }
 669
 670         /* Send metadata stream to relayd if needed. */
 671         ret = send_stream_to_relayd(metadata->metadata_stream);
 672         if (ret < 0) {
 673                 ret = LTTCOMM_CONSUMERD_ERROR_METADATA;
 674                 goto error;
 675         }
 676
 677         ret = send_streams_to_thread(metadata, ctx);
 678         if (ret < 0) {
 679                 /*
 680                  * If we are unable to send the stream to the thread, there is
 681                  * a big problem so just stop everything.
 682                  */
 683                 ret = LTTCOMM_CONSUMERD_FATAL;
 684                 goto error;
 685         }
 686         /* List MUST be empty after or else it could be reused. */
 687         assert(cds_list_empty(&metadata->streams.head));
 688
 689         ret = 0;
 690
 691 error:
 692         return ret;
 693 }
 694
 695 /*
 696  * Receive the metadata updates from the sessiond.
 697  */
 698 int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
 699                 uint64_t len, struct lttng_consumer_channel *channel)
 700 {
 701         int ret, ret_code = LTTNG_OK;
 702         char *metadata_str;
 703
 704         DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key, len);
 705
 706         metadata_str = zmalloc(len * sizeof(char));
 707         if (!metadata_str) {
 708                 PERROR("zmalloc metadata string");
 709                 ret_code = LTTCOMM_CONSUMERD_ENOMEM;
 710                 goto end;
 711         }
 712
 713         /* Receive metadata string. */
 714         ret = lttcomm_recv_unix_sock(sock, metadata_str, len);
 715         if (ret < 0) {
 716                 /* Session daemon is dead so return gracefully. */
 717                 ret_code = ret;
 718                 goto end_free;
 719         }
 720
 721         pthread_mutex_lock(&channel->metadata_cache->lock);
 722         ret = consumer_metadata_cache_write(channel, offset, len, metadata_str);
 723         if (ret < 0) {
 724                 /* Unable to handle metadata. Notify session daemon. */
 725                 ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
 726         }
 727         pthread_mutex_unlock(&channel->metadata_cache->lock);
 728
 729         while (consumer_metadata_cache_flushed(channel, offset + len)) {
 730                 DBG("Waiting for metadata to be flushed");
 731                 usleep(DEFAULT_METADATA_AVAILABILITY_WAIT_TIME);
 732         }
 733
 734 end_free:
 735         free(metadata_str);
 736 end:
 737         return ret_code;
 738 }
 739
 740 /*
 741  * Receive command from session daemon and process it.
 742  *
 743  * Return 1 on success else a negative value or 0.
 744  */
 745 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 746                 int sock, struct pollfd *consumer_sockpoll)
 747 {
 748         ssize_t ret;
 749         enum lttng_error_code ret_code = LTTNG_OK;
 750         struct lttcomm_consumer_msg msg;
 751         struct lttng_consumer_channel *channel = NULL;
 752
 753         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 754         if (ret != sizeof(msg)) {
 755                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 756                         ret, sizeof(msg));
 757                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 758                 /*
 759                  * The ret value might 0 meaning an orderly shutdown but this is ok
 760                  * since the caller handles this.
 761                  */
 762                 return ret;
 763         }
 764         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 765                 /*
 766                  * Notify the session daemon that the command is completed.
 767                  *
 768                  * On transport layer error, the function call will print an error
 769                  * message so handling the returned code is a bit useless since we
 770                  * return an error code anyway.
 771                  */
 772                 (void) consumer_send_status_msg(sock, ret_code);
 773                 return -ENOENT;
 774         }
 775
 776         /* relayd needs RCU read-side lock */
 777         rcu_read_lock();
 778
 779         switch (msg.cmd_type) {
 780         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 781         {
 782                 /* Session daemon status message are handled in the following call. */
 783                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 784                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 785                                 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id);
 786                 goto end_nosignal;
 787         }
 788         case LTTNG_CONSUMER_DESTROY_RELAYD:
 789         {
 790                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 791                 struct consumer_relayd_sock_pair *relayd;
 792
 793                 DBG("UST consumer destroying relayd %" PRIu64, index);
 794
 795                 /* Get relayd reference if exists. */
 796                 relayd = consumer_find_relayd(index);
 797                 if (relayd == NULL) {
 798                         DBG("Unable to find relayd %" PRIu64, index);
 799                         ret_code = LTTNG_ERR_NO_CONSUMER;
 800                 }
 801
 802                 /*
 803                  * Each relayd socket pair has a refcount of stream attached to it
 804                  * which tells if the relayd is still active or not depending on the
 805                  * refcount value.
 806                  *
 807                  * This will set the destroy flag of the relayd object and destroy it
 808                  * if the refcount reaches zero when called.
 809                  *
 810                  * The destroy can happen either here or when a stream fd hangs up.
 811                  */
 812                 if (relayd) {
 813                         consumer_flag_relayd_for_destroy(relayd);
 814                 }
 815
 816                 goto end_msg_sessiond;
 817         }
 818         case LTTNG_CONSUMER_UPDATE_STREAM:
 819         {
 820                 rcu_read_unlock();
 821                 return -ENOSYS;
 822         }
 823         case LTTNG_CONSUMER_DATA_PENDING:
 824         {
 825                 int ret, is_data_pending;
 826                 uint64_t id = msg.u.data_pending.session_id;
 827
 828                 DBG("UST consumer data pending command for id %" PRIu64, id);
 829
 830                 is_data_pending = consumer_data_pending(id);
 831
 832                 /* Send back returned value to session daemon */
 833                 ret = lttcomm_send_unix_sock(sock, &is_data_pending,
 834                                 sizeof(is_data_pending));
 835                 if (ret < 0) {
 836                         DBG("Error when sending the data pending ret code: %d", ret);
 837                 }
 838
 839                 /*
 840                  * No need to send back a status message since the data pending
 841                  * returned value is the response.
 842                  */
 843                 break;
 844         }
 845         case LTTNG_CONSUMER_ASK_CHANNEL_CREATION:
 846         {
 847                 int ret;
 848                 struct ustctl_consumer_channel_attr attr;
 849
 850                 /* Create a plain object and reserve a channel key. */
 851                 channel = allocate_channel(msg.u.ask_channel.session_id,
 852                                 msg.u.ask_channel.pathname, msg.u.ask_channel.name,
 853                                 msg.u.ask_channel.uid, msg.u.ask_channel.gid,
 854                                 msg.u.ask_channel.relayd_id, msg.u.ask_channel.key,
 855                                 (enum lttng_event_output) msg.u.ask_channel.output,
 856                                 msg.u.ask_channel.tracefile_size,
 857                                 msg.u.ask_channel.tracefile_count);
 858                 if (!channel) {
 859                         goto end_channel_error;
 860                 }
 861
 862                 /* Build channel attributes from received message. */
 863                 attr.subbuf_size = msg.u.ask_channel.subbuf_size;
 864                 attr.num_subbuf = msg.u.ask_channel.num_subbuf;
 865                 attr.overwrite = msg.u.ask_channel.overwrite;
 866                 attr.switch_timer_interval = msg.u.ask_channel.switch_timer_interval;
 867                 attr.read_timer_interval = msg.u.ask_channel.read_timer_interval;
 868                 attr.chan_id = msg.u.ask_channel.chan_id;
 869                 memcpy(attr.uuid, msg.u.ask_channel.uuid, sizeof(attr.uuid));
 870
 871                 /* Translate the event output type to UST. */
 872                 switch (channel->output) {
 873                 case LTTNG_EVENT_SPLICE:
 874                         /* Splice not supported so fallback on mmap(). */
 875                 case LTTNG_EVENT_MMAP:
 876                 default:
 877                         attr.output = CONSUMER_CHANNEL_MMAP;
 878                         break;
 879                 };
 880
 881                 /* Translate and save channel type. */
 882                 switch (msg.u.ask_channel.type) {
 883                 case LTTNG_UST_CHAN_PER_CPU:
 884                         channel->type = CONSUMER_CHANNEL_TYPE_DATA;
 885                         attr.type = LTTNG_UST_CHAN_PER_CPU;
 886                         break;
 887                 case LTTNG_UST_CHAN_METADATA:
 888                         channel->type = CONSUMER_CHANNEL_TYPE_METADATA;
 889                         attr.type = LTTNG_UST_CHAN_METADATA;
 890                         break;
 891                 default:
 892                         assert(0);
 893                         goto error_fatal;
 894                 };
 895
 896                 ret = ask_channel(ctx, sock, channel, &attr);
 897                 if (ret < 0) {
 898                         goto end_channel_error;
 899                 }
 900
 901                 /*
 902                  * Add the channel to the internal state AFTER all streams were created
 903                  * and successfully sent to session daemon. This way, all streams must
 904                  * be ready before this channel is visible to the threads.
 905                  */
 906                 ret = add_channel(channel, ctx);
 907                 if (ret < 0) {
 908                         goto end_channel_error;
 909                 }
 910
 911
 912                 /*
 913                  * Channel and streams are now created. Inform the session daemon that
 914                  * everything went well and should wait to receive the channel and
 915                  * streams with ustctl API.
 916                  */
 917                 ret = consumer_send_status_channel(sock, channel);
 918                 if (ret < 0) {
 919                         /*
 920                          * There is probably a problem on the socket so the poll will get
 921                          * it and clean everything up.
 922                          */
 923                         goto end_nosignal;
 924                 }
 925
 926                 if (msg.u.ask_channel.type == LTTNG_UST_CHAN_METADATA) {
 927                         ret = consumer_metadata_cache_allocate(channel);
 928                         if (ret < 0) {
 929                                 ERR("Allocating metadata cache");
 930                                 goto end_channel_error;
 931                         }
 932                         consumer_timer_switch_start(channel, attr.switch_timer_interval);
 933                         attr.switch_timer_interval = 0;
 934                 }
 935
 936                 break;
 937         }
 938         case LTTNG_CONSUMER_GET_CHANNEL:
 939         {
 940                 int ret, relayd_err = 0;
 941                 uint64_t key = msg.u.get_channel.key;
 942                 struct lttng_consumer_channel *channel;
 943
 944                 channel = consumer_find_channel(key);
 945                 if (!channel) {
 946                         ERR("UST consumer get channel key %" PRIu64 " not found", key);
 947                         ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 948                         goto end_msg_sessiond;
 949                 }
 950
 951                 /* Inform sessiond that we are about to send channel and streams. */
 952                 ret = consumer_send_status_msg(sock, LTTNG_OK);
 953                 if (ret < 0) {
 954                         /* Somehow, the session daemon is not responding anymore. */
 955                         goto end_nosignal;
 956                 }
 957
 958                 /* Send everything to sessiond. */
 959                 ret = send_sessiond_channel(sock, channel, ctx, &relayd_err);
 960                 if (ret < 0) {
 961                         if (relayd_err) {
 962                                 /*
 963                                  * We were unable to send to the relayd the stream so avoid
 964                                  * sending back a fatal error to the thread since this is OK
 965                                  * and the consumer can continue its work.
 966                                  */
 967                                 ret_code = LTTNG_ERR_RELAYD_CONNECT_FAIL;
 968                                 goto end_msg_sessiond;
 969                         }
 970                         /*
 971                          * The communicaton was broken hence there is a bad state between
 972                          * the consumer and sessiond so stop everything.
 973                          */
 974                         goto error_fatal;
 975                 }
 976
 977                 ret = send_streams_to_thread(channel, ctx);
 978                 if (ret < 0) {
 979                         /*
 980                          * If we are unable to send the stream to the thread, there is
 981                          * a big problem so just stop everything.
 982                          */
 983                         goto error_fatal;
 984                 }
 985                 /* List MUST be empty after or else it could be reused. */
 986                 assert(cds_list_empty(&channel->streams.head));
 987
 988                 goto end_msg_sessiond;
 989         }
 990         case LTTNG_CONSUMER_DESTROY_CHANNEL:
 991         {
 992                 uint64_t key = msg.u.destroy_channel.key;
 993                 struct lttng_consumer_channel *channel;
 994
 995                 channel = consumer_find_channel(key);
 996                 if (!channel) {
 997                         ERR("UST consumer get channel key %" PRIu64 " not found", key);
 998                         ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
 999                         goto end_msg_sessiond;
1000                 }
1001
1002                 destroy_channel(channel);
1003
1004                 goto end_msg_sessiond;
1005         }
1006         case LTTNG_CONSUMER_CLOSE_METADATA:
1007         {
1008                 int ret;
1009
1010                 ret = close_metadata(msg.u.close_metadata.key);
1011                 if (ret != 0) {
1012                         ret_code = ret;
1013                 }
1014
1015                 goto end_msg_sessiond;
1016         }
1017         case LTTNG_CONSUMER_FLUSH_CHANNEL:
1018         {
1019                 int ret;
1020
1021                 ret = flush_channel(msg.u.flush_channel.key);
1022                 if (ret != 0) {
1023                         ret_code = ret;
1024                 }
1025
1026                 goto end_msg_sessiond;
1027         }
1028         case LTTNG_CONSUMER_PUSH_METADATA:
1029         {
1030                 int ret;
1031                 uint64_t len = msg.u.push_metadata.len;
1032                 uint64_t key = msg.u.push_metadata.key;
1033                 uint64_t offset = msg.u.push_metadata.target_offset;
1034                 struct lttng_consumer_channel *channel;
1035
1036                 DBG("UST consumer push metadata key %" PRIu64 " of len %" PRIu64, key,
1037                                 len);
1038
1039                 channel = consumer_find_channel(key);
1040                 if (!channel) {
1041                         ERR("UST consumer push metadata %" PRIu64 " not found", key);
1042                         ret_code = LTTNG_ERR_UST_CHAN_NOT_FOUND;
1043                 }
1044
1045                 /* Tell session daemon we are ready to receive the metadata. */
1046                 ret = consumer_send_status_msg(sock, LTTNG_OK);
1047                 if (ret < 0) {
1048                         /* Somehow, the session daemon is not responding anymore. */
1049                         goto error_fatal;
1050                 }
1051
1052                 /* Wait for more data. */
1053                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
1054                         goto end_nosignal;
1055                 }
1056
1057                 ret = lttng_ustconsumer_recv_metadata(sock, key, offset,
1058                                 len, channel);
1059                 if (ret < 0) {
1060                         /* error receiving from sessiond */
1061                         goto end_nosignal;
1062                 } else {
1063                         ret_code = ret;
1064                         goto end_msg_sessiond;
1065                 }
1066         }
1067         case LTTNG_CONSUMER_SETUP_METADATA:
1068         {
1069                 int ret;
1070
1071                 ret = setup_metadata(ctx, msg.u.setup_metadata.key);
1072                 if (ret) {
1073                         ret_code = ret;
1074                 }
1075                 goto end_msg_sessiond;
1076         }
1077         default:
1078                 break;
1079         }
1080
1081 end_nosignal:
1082         rcu_read_unlock();
1083
1084         /*
1085          * Return 1 to indicate success since the 0 value can be a socket
1086          * shutdown during the recv() or send() call.
1087          */
1088         return 1;
1089
1090 end_msg_sessiond:
1091         /*
1092          * The returned value here is not useful since either way we'll return 1 to
1093          * the caller because the session daemon socket management is done
1094          * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1095          */
1096         (void) consumer_send_status_msg(sock, ret_code);
1097         rcu_read_unlock();
1098         return 1;
1099 end_channel_error:
1100         if (channel) {
1101                 /*
1102                  * Free channel here since no one has a reference to it. We don't
1103                  * free after that because a stream can store this pointer.
1104                  */
1105                 destroy_channel(channel);
1106         }
1107         /* We have to send a status channel message indicating an error. */
1108         ret = consumer_send_status_channel(sock, NULL);
1109         if (ret < 0) {
1110                 /* Stop everything if session daemon can not be notified. */
1111                 goto error_fatal;
1112         }
1113         rcu_read_unlock();
1114         return 1;
1115 error_fatal:
1116         rcu_read_unlock();
1117         /* This will issue a consumer stop. */
1118         return -1;
1119 }
1120
1121 /*
1122  * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
1123  * compiled out, we isolate it in this library.
1124  */
1125 int lttng_ustctl_get_mmap_read_offset(struct lttng_consumer_stream *stream,
1126                 unsigned long *off)
1127 {
1128         assert(stream);
1129         assert(stream->ustream);
1130
1131         return ustctl_get_mmap_read_offset(stream->ustream, off);
1132 }
1133
1134 /*
1135  * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
1136  * compiled out, we isolate it in this library.
1137  */
1138 void *lttng_ustctl_get_mmap_base(struct lttng_consumer_stream *stream)
1139 {
1140         assert(stream);
1141         assert(stream->ustream);
1142
1143         return ustctl_get_mmap_base(stream->ustream);
1144 }
1145
1146 /*
1147  * Take a snapshot for a specific fd
1148  *
1149  * Returns 0 on success, < 0 on error
1150  */
1151 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_stream *stream)
1152 {
1153         assert(stream);
1154         assert(stream->ustream);
1155
1156         return ustctl_snapshot(stream->ustream);
1157 }
1158
1159 /*
1160  * Get the produced position
1161  *
1162  * Returns 0 on success, < 0 on error
1163  */
1164 int lttng_ustconsumer_get_produced_snapshot(
1165                 struct lttng_consumer_stream *stream, unsigned long *pos)
1166 {
1167         assert(stream);
1168         assert(stream->ustream);
1169         assert(pos);
1170
1171         return ustctl_snapshot_get_produced(stream->ustream, pos);
1172 }
1173
1174 /*
1175  * Called when the stream signal the consumer that it has hang up.
1176  */
1177 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
1178 {
1179         assert(stream);
1180         assert(stream->ustream);
1181
1182         ustctl_flush_buffer(stream->ustream, 0);
1183         stream->hangup_flush_done = 1;
1184 }
1185
1186 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
1187 {
1188         assert(chan);
1189         assert(chan->uchan);
1190
1191         ustctl_destroy_channel(chan->uchan);
1192 }
1193
1194 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
1195 {
1196         assert(stream);
1197         assert(stream->ustream);
1198
1199         ustctl_destroy_stream(stream->ustream);
1200 }
1201
1202 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
1203                 struct lttng_consumer_local_data *ctx)
1204 {
1205         unsigned long len, subbuf_size, padding;
1206         int err;
1207         long ret = 0;
1208         char dummy;
1209         struct ustctl_consumer_stream *ustream;
1210
1211         assert(stream);
1212         assert(stream->ustream);
1213         assert(ctx);
1214
1215         DBG2("In UST read_subbuffer (wait_fd: %d, name: %s)", stream->wait_fd,
1216                         stream->name);
1217
1218         /* Ease our life for what's next. */
1219         ustream = stream->ustream;
1220
1221         /* We can consume the 1 byte written into the wait_fd by UST */
1222         if (!stream->hangup_flush_done) {
1223                 ssize_t readlen;
1224
1225                 do {
1226                         readlen = read(stream->wait_fd, &dummy, 1);
1227                 } while (readlen == -1 && errno == EINTR);
1228                 if (readlen == -1) {
1229                         ret = readlen;
1230                         goto end;
1231                 }
1232         }
1233
1234         /* Get the next subbuffer */
1235         err = ustctl_get_next_subbuf(ustream);
1236         if (err != 0) {
1237                 ret = err;      /* ustctl_get_next_subbuf returns negative, caller expect positive. */
1238                 /*
1239                  * This is a debug message even for single-threaded consumer,
1240                  * because poll() have more relaxed criterions than get subbuf,
1241                  * so get_subbuf may fail for short race windows where poll()
1242                  * would issue wakeups.
1243                  */
1244                 DBG("Reserving sub buffer failed (everything is normal, "
1245                                 "it is due to concurrency) [ret: %d]", err);
1246                 goto end;
1247         }
1248         assert(stream->chan->output == CONSUMER_CHANNEL_MMAP);
1249         /* Get the full padded subbuffer size */
1250         err = ustctl_get_padded_subbuf_size(ustream, &len);
1251         assert(err == 0);
1252
1253         /* Get subbuffer data size (without padding) */
1254         err = ustctl_get_subbuf_size(ustream, &subbuf_size);
1255         assert(err == 0);
1256
1257         /* Make sure we don't get a subbuffer size bigger than the padded */
1258         assert(len >= subbuf_size);
1259
1260         padding = len - subbuf_size;
1261         /* write the subbuffer to the tracefile */
1262         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
1263         /*
1264          * The mmap operation should write subbuf_size amount of data when network
1265          * streaming or the full padding (len) size when we are _not_ streaming.
1266          */
1267         if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
1268                         (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
1269                 /*
1270                  * Display the error but continue processing to try to release the
1271                  * subbuffer. This is a DBG statement since any unexpected kill or
1272                  * signal, the application gets unregistered, relayd gets closed or
1273                  * anything that affects the buffer lifetime will trigger this error.
1274                  * So, for the sake of the user, don't print this error since it can
1275                  * happen and it is OK with the code flow.
1276                  */
1277                 DBG("Error writing to tracefile "
1278                                 "(ret: %ld != len: %lu != subbuf_size: %lu)",
1279                                 ret, len, subbuf_size);
1280         }
1281         err = ustctl_put_next_subbuf(ustream);
1282         assert(err == 0);
1283
1284 end:
1285         return ret;
1286 }
1287
1288 /*
1289  * Called when a stream is created.
1290  *
1291  * Return 0 on success or else a negative value.
1292  */
1293 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1294 {
1295         int ret;
1296
1297         /* Don't create anything if this is set for streaming. */
1298         if (stream->net_seq_idx == (uint64_t) -1ULL) {
1299                 ret = utils_create_stream_file(stream->chan->pathname, stream->name,
1300                                 stream->chan->tracefile_size, stream->tracefile_count_current,
1301                                 stream->uid, stream->gid);
1302                 if (ret < 0) {
1303                         goto error;
1304                 }
1305                 stream->out_fd = ret;
1306                 stream->tracefile_size_current = 0;
1307         }
1308         ret = 0;
1309
1310 error:
1311         return ret;
1312 }
1313
1314 /*
1315  * Check if data is still being extracted from the buffers for a specific
1316  * stream. Consumer data lock MUST be acquired before calling this function
1317  * and the stream lock.
1318  *
1319  * Return 1 if the traced data are still getting read else 0 meaning that the
1320  * data is available for trace viewer reading.
1321  */
1322 int lttng_ustconsumer_data_pending(struct lttng_consumer_stream *stream)
1323 {
1324         int ret;
1325
1326         assert(stream);
1327         assert(stream->ustream);
1328
1329         DBG("UST consumer checking data pending");
1330
1331         ret = ustctl_get_next_subbuf(stream->ustream);
1332         if (ret == 0) {
1333                 /* There is still data so let's put back this subbuffer. */
1334                 ret = ustctl_put_subbuf(stream->ustream);
1335                 assert(ret == 0);
1336                 ret = 1;  /* Data is pending */
1337                 goto end;
1338         }
1339
1340         /* Data is NOT pending so ready to be read. */
1341         ret = 0;
1342
1343 end:
1344         return ret;
1345 }
1346
1347 /*
1348  * Close every metadata stream wait fd of the metadata hash table. This
1349  * function MUST be used very carefully so not to run into a race between the
1350  * metadata thread handling streams and this function closing their wait fd.
1351  *
1352  * For UST, this is used when the session daemon hangs up. Its the metadata
1353  * producer so calling this is safe because we are assured that no state change
1354  * can occur in the metadata thread for the streams in the hash table.
1355  */
1356 void lttng_ustconsumer_close_metadata(struct lttng_ht *metadata_ht)
1357 {
1358         int ret;
1359         struct lttng_ht_iter iter;
1360         struct lttng_consumer_stream *stream;
1361
1362         assert(metadata_ht);
1363         assert(metadata_ht->ht);
1364
1365         DBG("UST consumer closing all metadata streams");
1366
1367         rcu_read_lock();
1368         cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream,
1369                         node.node) {
1370                 int fd = stream->wait_fd;
1371
1372                 /*
1373                  * Whatever happens here we have to continue to try to close every
1374                  * streams. Let's report at least the error on failure.
1375                  */
1376                 ret = ustctl_stream_close_wakeup_fd(stream->ustream);
1377                 if (ret) {
1378                         ERR("Unable to close metadata stream fd %d ret %d", fd, ret);
1379                 }
1380                 DBG("Metadata wait fd %d closed", fd);
1381         }
1382         rcu_read_unlock();
1383 }
1384
1385 void lttng_ustconsumer_close_stream_wakeup(struct lttng_consumer_stream *stream)
1386 {
1387         int ret;
1388
1389         ret = ustctl_stream_close_wakeup_fd(stream->ustream);
1390         if (ret < 0) {
1391                 ERR("Unable to close wakeup fd");
1392         }
1393 }
1394
1395 int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
1396                 struct lttng_consumer_channel *channel)
1397 {
1398         struct lttcomm_metadata_request_msg request;
1399         struct lttcomm_consumer_msg msg;
1400         enum lttng_error_code ret_code = LTTNG_OK;
1401         uint64_t len, key, offset;
1402         int ret;
1403
1404         assert(channel);
1405         assert(channel->metadata_cache);
1406
1407         /* send the metadata request to sessiond */
1408         switch (consumer_data.type) {
1409         case LTTNG_CONSUMER64_UST:
1410                 request.bits_per_long = 64;
1411                 break;
1412         case LTTNG_CONSUMER32_UST:
1413                 request.bits_per_long = 32;
1414                 break;
1415         default:
1416                 request.bits_per_long = 0;
1417                 break;
1418         }
1419
1420         request.session_id = channel->session_id;
1421         request.uid = channel->uid;
1422         request.key = channel->key;
1423         DBG("Sending metadata request to sessiond, session %" PRIu64,
1424                         channel->session_id);
1425
1426         ret = lttcomm_send_unix_sock(ctx->consumer_metadata_socket, &request,
1427                         sizeof(request));
1428         if (ret < 0) {
1429                 ERR("Asking metadata to sessiond");
1430                 goto end;
1431         }
1432
1433         /* Receive the metadata from sessiond */
1434         ret = lttcomm_recv_unix_sock(ctx->consumer_metadata_socket, &msg,
1435                         sizeof(msg));
1436         if (ret != sizeof(msg)) {
1437                 DBG("Consumer received unexpected message size %d (expects %zu)",
1438                         ret, sizeof(msg));
1439                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
1440                 /*
1441                  * The ret value might 0 meaning an orderly shutdown but this is ok
1442                  * since the caller handles this.
1443                  */
1444                 goto end;
1445         }
1446
1447         if (msg.cmd_type == LTTNG_ERR_UND) {
1448                 /* No registry found */
1449                 (void) consumer_send_status_msg(ctx->consumer_metadata_socket,
1450                                 ret_code);
1451                 ret = 0;
1452                 goto end;
1453         } else if (msg.cmd_type != LTTNG_CONSUMER_PUSH_METADATA) {
1454                 ERR("Unexpected cmd_type received %d", msg.cmd_type);
1455                 ret = -1;
1456                 goto end;
1457         }
1458
1459         len = msg.u.push_metadata.len;
1460         key = msg.u.push_metadata.key;
1461         offset = msg.u.push_metadata.target_offset;
1462
1463         assert(key == channel->key);
1464         if (len == 0) {
1465                 DBG("No new metadata to receive for key %" PRIu64, key);
1466         }
1467
1468         /* Tell session daemon we are ready to receive the metadata. */
1469         ret = consumer_send_status_msg(ctx->consumer_metadata_socket,
1470                         LTTNG_OK);
1471         if (ret < 0 || len == 0) {
1472                 /*
1473                  * Somehow, the session daemon is not responding anymore or there is
1474                  * nothing to receive.
1475                  */
1476                 goto end;
1477         }
1478
1479         ret_code = lttng_ustconsumer_recv_metadata(ctx->consumer_metadata_socket,
1480                         key, offset, len, channel);
1481         (void) consumer_send_status_msg(ctx->consumer_metadata_socket, ret_code);
1482         ret = 0;
1483
1484 end:
1485         return ret;
1486 }