src/common/kernel-consumer/kernel-consumer.c

   1 /*
   2  * Copyright (C) 2011 Julien Desfossez <julien.desfossez@polymtl.ca>
   3  * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  * Copyright (C) 2017 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-only
   7  *
   8  */
   9
  10 #define _LGPL_SOURCE
  11 #include <poll.h>
  12 #include <pthread.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/mman.h>
  16 #include <sys/socket.h>
  17 #include <sys/types.h>
  18 #include <inttypes.h>
  19 #include <unistd.h>
  20 #include <sys/stat.h>
  21 #include <stdint.h>
  22
  23 #include <bin/lttng-consumerd/health-consumerd.h>
  24 #include <common/common.h>
  25 #include <common/kernel-ctl/kernel-ctl.h>
  26 #include <common/sessiond-comm/sessiond-comm.h>
  27 #include <common/sessiond-comm/relayd.h>
  28 #include <common/compat/fcntl.h>
  29 #include <common/compat/endian.h>
  30 #include <common/pipe.h>
  31 #include <common/relayd/relayd.h>
  32 #include <common/utils.h>
  33 #include <common/consumer/consumer-stream.h>
  34 #include <common/index/index.h>
  35 #include <common/consumer/consumer-timer.h>
  36 #include <common/optional.h>
  37 #include <common/buffer-view.h>
  38 #include <common/consumer/consumer.h>
  39 #include <common/consumer/metadata-bucket.h>
  40
  41 #include "kernel-consumer.h"
  42
  43 extern struct lttng_consumer_global_data the_consumer_data;
  44 extern int consumer_poll_timeout;
  45
  46 /*
  47  * Take a snapshot for a specific fd
  48  *
  49  * Returns 0 on success, < 0 on error
  50  */
  51 int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream *stream)
  52 {
  53         int ret = 0;
  54         int infd = stream->wait_fd;
  55
  56         ret = kernctl_snapshot(infd);
  57         /*
  58          * -EAGAIN is not an error, it just means that there is no data to
  59          *  be read.
  60          */
  61         if (ret != 0 && ret != -EAGAIN) {
  62                 PERROR("Getting sub-buffer snapshot.");
  63         }
  64
  65         return ret;
  66 }
  67
  68 /*
  69  * Sample consumed and produced positions for a specific fd.
  70  *
  71  * Returns 0 on success, < 0 on error.
  72  */
  73 int lttng_kconsumer_sample_snapshot_positions(
  74                 struct lttng_consumer_stream *stream)
  75 {
  76         LTTNG_ASSERT(stream);
  77
  78         return kernctl_snapshot_sample_positions(stream->wait_fd);
  79 }
  80
  81 /*
  82  * Get the produced position
  83  *
  84  * Returns 0 on success, < 0 on error
  85  */
  86 int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
  87                 unsigned long *pos)
  88 {
  89         int ret;
  90         int infd = stream->wait_fd;
  91
  92         ret = kernctl_snapshot_get_produced(infd, pos);
  93         if (ret != 0) {
  94                 PERROR("kernctl_snapshot_get_produced");
  95         }
  96
  97         return ret;
  98 }
  99
 100 /*
 101  * Get the consumerd position
 102  *
 103  * Returns 0 on success, < 0 on error
 104  */
 105 int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
 106                 unsigned long *pos)
 107 {
 108         int ret;
 109         int infd = stream->wait_fd;
 110
 111         ret = kernctl_snapshot_get_consumed(infd, pos);
 112         if (ret != 0) {
 113                 PERROR("kernctl_snapshot_get_consumed");
 114         }
 115
 116         return ret;
 117 }
 118
 119 static
 120 int get_current_subbuf_addr(struct lttng_consumer_stream *stream,
 121                 const char **addr)
 122 {
 123         int ret;
 124         unsigned long mmap_offset;
 125         const char *mmap_base = stream->mmap_base;
 126
 127         ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
 128         if (ret < 0) {
 129                 PERROR("Failed to get mmap read offset");
 130                 goto error;
 131         }
 132
 133         *addr = mmap_base + mmap_offset;
 134 error:
 135         return ret;
 136 }
 137
 138 /*
 139  * Take a snapshot of all the stream of a channel
 140  * RCU read-side lock must be held across this function to ensure existence of
 141  * channel. The channel lock must be held by the caller.
 142  *
 143  * Returns 0 on success, < 0 on error
 144  */
 145 static int lttng_kconsumer_snapshot_channel(
 146                 struct lttng_consumer_channel *channel,
 147                 uint64_t key, char *path, uint64_t relayd_id,
 148                 uint64_t nb_packets_per_stream,
 149                 struct lttng_consumer_local_data *ctx)
 150 {
 151         int ret;
 152         struct lttng_consumer_stream *stream;
 153
 154         DBG("Kernel consumer snapshot channel %" PRIu64, key);
 155
 156         rcu_read_lock();
 157
 158         /* Splice is not supported yet for channel snapshot. */
 159         if (channel->output != CONSUMER_CHANNEL_MMAP) {
 160                 ERR("Unsupported output type for channel \"%s\": mmap output is required to record a snapshot",
 161                                 channel->name);
 162                 ret = -1;
 163                 goto end;
 164         }
 165
 166         cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
 167                 unsigned long consumed_pos, produced_pos;
 168
 169                 health_code_update();
 170
 171                 /*
 172                  * Lock stream because we are about to change its state.
 173                  */
 174                 pthread_mutex_lock(&stream->lock);
 175
 176                 LTTNG_ASSERT(channel->trace_chunk);
 177                 if (!lttng_trace_chunk_get(channel->trace_chunk)) {
 178                         /*
 179                          * Can't happen barring an internal error as the channel
 180                          * holds a reference to the trace chunk.
 181                          */
 182                         ERR("Failed to acquire reference to channel's trace chunk");
 183                         ret = -1;
 184                         goto end_unlock;
 185                 }
 186                 LTTNG_ASSERT(!stream->trace_chunk);
 187                 stream->trace_chunk = channel->trace_chunk;
 188
 189                 /*
 190                  * Assign the received relayd ID so we can use it for streaming. The streams
 191                  * are not visible to anyone so this is OK to change it.
 192                  */
 193                 stream->net_seq_idx = relayd_id;
 194                 channel->relayd_id = relayd_id;
 195                 if (relayd_id != (uint64_t) -1ULL) {
 196                         ret = consumer_send_relayd_stream(stream, path);
 197                         if (ret < 0) {
 198                                 ERR("sending stream to relayd");
 199                                 goto end_unlock;
 200                         }
 201                 } else {
 202                         ret = consumer_stream_create_output_files(stream,
 203                                         false);
 204                         if (ret < 0) {
 205                                 goto end_unlock;
 206                         }
 207                         DBG("Kernel consumer snapshot stream (%" PRIu64 ")",
 208                                         stream->key);
 209                 }
 210
 211                 ret = kernctl_buffer_flush_empty(stream->wait_fd);
 212                 if (ret < 0) {
 213                         /*
 214                          * Doing a buffer flush which does not take into
 215                          * account empty packets. This is not perfect
 216                          * for stream intersection, but required as a
 217                          * fall-back when "flush_empty" is not
 218                          * implemented by lttng-modules.
 219                          */
 220                         ret = kernctl_buffer_flush(stream->wait_fd);
 221                         if (ret < 0) {
 222                                 ERR("Failed to flush kernel stream");
 223                                 goto end_unlock;
 224                         }
 225                         goto end_unlock;
 226                 }
 227
 228                 ret = lttng_kconsumer_take_snapshot(stream);
 229                 if (ret < 0) {
 230                         ERR("Taking kernel snapshot");
 231                         goto end_unlock;
 232                 }
 233
 234                 ret = lttng_kconsumer_get_produced_snapshot(stream, &produced_pos);
 235                 if (ret < 0) {
 236                         ERR("Produced kernel snapshot position");
 237                         goto end_unlock;
 238                 }
 239
 240                 ret = lttng_kconsumer_get_consumed_snapshot(stream, &consumed_pos);
 241                 if (ret < 0) {
 242                         ERR("Consumerd kernel snapshot position");
 243                         goto end_unlock;
 244                 }
 245
 246                 consumed_pos = consumer_get_consume_start_pos(consumed_pos,
 247                                 produced_pos, nb_packets_per_stream,
 248                                 stream->max_sb_size);
 249
 250                 while ((long) (consumed_pos - produced_pos) < 0) {
 251                         ssize_t read_len;
 252                         unsigned long len, padded_len;
 253                         const char *subbuf_addr;
 254                         struct lttng_buffer_view subbuf_view;
 255
 256                         health_code_update();
 257                         DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 258
 259                         ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
 260                         if (ret < 0) {
 261                                 if (ret != -EAGAIN) {
 262                                         PERROR("kernctl_get_subbuf snapshot");
 263                                         goto end_unlock;
 264                                 }
 265                                 DBG("Kernel consumer get subbuf failed. Skipping it.");
 266                                 consumed_pos += stream->max_sb_size;
 267                                 stream->chan->lost_packets++;
 268                                 continue;
 269                         }
 270
 271                         ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
 272                         if (ret < 0) {
 273                                 ERR("Snapshot kernctl_get_subbuf_size");
 274                                 goto error_put_subbuf;
 275                         }
 276
 277                         ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
 278                         if (ret < 0) {
 279                                 ERR("Snapshot kernctl_get_padded_subbuf_size");
 280                                 goto error_put_subbuf;
 281                         }
 282
 283                         ret = get_current_subbuf_addr(stream, &subbuf_addr);
 284                         if (ret) {
 285                                 goto error_put_subbuf;
 286                         }
 287
 288                         subbuf_view = lttng_buffer_view_init(
 289                                         subbuf_addr, 0, padded_len);
 290                         read_len = lttng_consumer_on_read_subbuffer_mmap(
 291                                         stream, &subbuf_view,
 292                                         padded_len - len);
 293                         /*
 294                          * We write the padded len in local tracefiles but the data len
 295                          * when using a relay. Display the error but continue processing
 296                          * to try to release the subbuffer.
 297                          */
 298                         if (relayd_id != (uint64_t) -1ULL) {
 299                                 if (read_len != len) {
 300                                         ERR("Error sending to the relay (ret: %zd != len: %lu)",
 301                                                         read_len, len);
 302                                 }
 303                         } else {
 304                                 if (read_len != padded_len) {
 305                                         ERR("Error writing to tracefile (ret: %zd != len: %lu)",
 306                                                         read_len, padded_len);
 307                                 }
 308                         }
 309
 310                         ret = kernctl_put_subbuf(stream->wait_fd);
 311                         if (ret < 0) {
 312                                 ERR("Snapshot kernctl_put_subbuf");
 313                                 goto end_unlock;
 314                         }
 315                         consumed_pos += stream->max_sb_size;
 316                 }
 317
 318                 if (relayd_id == (uint64_t) -1ULL) {
 319                         if (stream->out_fd >= 0) {
 320                                 ret = close(stream->out_fd);
 321                                 if (ret < 0) {
 322                                         PERROR("Kernel consumer snapshot close out_fd");
 323                                         goto end_unlock;
 324                                 }
 325                                 stream->out_fd = -1;
 326                         }
 327                 } else {
 328                         close_relayd_stream(stream);
 329                         stream->net_seq_idx = (uint64_t) -1ULL;
 330                 }
 331                 lttng_trace_chunk_put(stream->trace_chunk);
 332                 stream->trace_chunk = NULL;
 333                 pthread_mutex_unlock(&stream->lock);
 334         }
 335
 336         /* All good! */
 337         ret = 0;
 338         goto end;
 339
 340 error_put_subbuf:
 341         ret = kernctl_put_subbuf(stream->wait_fd);
 342         if (ret < 0) {
 343                 ERR("Snapshot kernctl_put_subbuf error path");
 344         }
 345 end_unlock:
 346         pthread_mutex_unlock(&stream->lock);
 347 end:
 348         rcu_read_unlock();
 349         return ret;
 350 }
 351
 352 /*
 353  * Read the whole metadata available for a snapshot.
 354  * RCU read-side lock must be held across this function to ensure existence of
 355  * metadata_channel. The channel lock must be held by the caller.
 356  *
 357  * Returns 0 on success, < 0 on error
 358  */
 359 static int lttng_kconsumer_snapshot_metadata(
 360                 struct lttng_consumer_channel *metadata_channel,
 361                 uint64_t key, char *path, uint64_t relayd_id,
 362                 struct lttng_consumer_local_data *ctx)
 363 {
 364         int ret, use_relayd = 0;
 365         ssize_t ret_read;
 366         struct lttng_consumer_stream *metadata_stream;
 367
 368         LTTNG_ASSERT(ctx);
 369
 370         DBG("Kernel consumer snapshot metadata with key %" PRIu64 " at path %s",
 371                         key, path);
 372
 373         rcu_read_lock();
 374
 375         metadata_stream = metadata_channel->metadata_stream;
 376         LTTNG_ASSERT(metadata_stream);
 377
 378         pthread_mutex_lock(&metadata_stream->lock);
 379         LTTNG_ASSERT(metadata_channel->trace_chunk);
 380         LTTNG_ASSERT(metadata_stream->trace_chunk);
 381
 382         /* Flag once that we have a valid relayd for the stream. */
 383         if (relayd_id != (uint64_t) -1ULL) {
 384                 use_relayd = 1;
 385         }
 386
 387         if (use_relayd) {
 388                 ret = consumer_send_relayd_stream(metadata_stream, path);
 389                 if (ret < 0) {
 390                         goto error_snapshot;
 391                 }
 392         } else {
 393                 ret = consumer_stream_create_output_files(metadata_stream,
 394                                 false);
 395                 if (ret < 0) {
 396                         goto error_snapshot;
 397                 }
 398         }
 399
 400         do {
 401                 health_code_update();
 402
 403                 ret_read = lttng_consumer_read_subbuffer(metadata_stream, ctx, true);
 404                 if (ret_read < 0) {
 405                         ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
 406                                         ret_read);
 407                         ret = ret_read;
 408                         goto error_snapshot;
 409                 }
 410         } while (ret_read > 0);
 411
 412         if (use_relayd) {
 413                 close_relayd_stream(metadata_stream);
 414                 metadata_stream->net_seq_idx = (uint64_t) -1ULL;
 415         } else {
 416                 if (metadata_stream->out_fd >= 0) {
 417                         ret = close(metadata_stream->out_fd);
 418                         if (ret < 0) {
 419                                 PERROR("Kernel consumer snapshot metadata close out_fd");
 420                                 /*
 421                                  * Don't go on error here since the snapshot was successful at this
 422                                  * point but somehow the close failed.
 423                                  */
 424                         }
 425                         metadata_stream->out_fd = -1;
 426                         lttng_trace_chunk_put(metadata_stream->trace_chunk);
 427                         metadata_stream->trace_chunk = NULL;
 428                 }
 429         }
 430
 431         ret = 0;
 432 error_snapshot:
 433         pthread_mutex_unlock(&metadata_stream->lock);
 434         cds_list_del(&metadata_stream->send_node);
 435         consumer_stream_destroy(metadata_stream, NULL);
 436         metadata_channel->metadata_stream = NULL;
 437         rcu_read_unlock();
 438         return ret;
 439 }
 440
 441 /*
 442  * Receive command from session daemon and process it.
 443  *
 444  * Return 1 on success else a negative value or 0.
 445  */
 446 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 447                 int sock, struct pollfd *consumer_sockpoll)
 448 {
 449         int ret_func;
 450         enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 451         struct lttcomm_consumer_msg msg;
 452
 453         health_code_update();
 454
 455         {
 456                 ssize_t ret_recv;
 457
 458                 ret_recv = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 459                 if (ret_recv != sizeof(msg)) {
 460                         if (ret_recv > 0) {
 461                                 lttng_consumer_send_error(ctx,
 462                                                 LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 463                                 ret_recv = -1;
 464                         }
 465                         return ret_recv;
 466                 }
 467         }
 468
 469         health_code_update();
 470
 471         /* Deprecated command */
 472         LTTNG_ASSERT(msg.cmd_type != LTTNG_CONSUMER_STOP);
 473
 474         health_code_update();
 475
 476         /* relayd needs RCU read-side protection */
 477         rcu_read_lock();
 478
 479         switch (msg.cmd_type) {
 480         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 481         {
 482                 /* Session daemon status message are handled in the following call. */
 483                 consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 484                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 485                                 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
 486                                 msg.u.relayd_sock.relayd_session_id);
 487                 goto end_nosignal;
 488         }
 489         case LTTNG_CONSUMER_ADD_CHANNEL:
 490         {
 491                 struct lttng_consumer_channel *new_channel;
 492                 int ret_send_status, ret_add_channel = 0;
 493                 const uint64_t chunk_id = msg.u.channel.chunk_id.value;
 494
 495                 health_code_update();
 496
 497                 /* First send a status message before receiving the fds. */
 498                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 499                 if (ret_send_status < 0) {
 500                         /* Somehow, the session daemon is not responding anymore. */
 501                         goto error_fatal;
 502                 }
 503
 504                 health_code_update();
 505
 506                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 507                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 508                                 msg.u.channel.session_id,
 509                                 msg.u.channel.chunk_id.is_set ?
 510                                                 &chunk_id : NULL,
 511                                 msg.u.channel.pathname,
 512                                 msg.u.channel.name,
 513                                 msg.u.channel.relayd_id, msg.u.channel.output,
 514                                 msg.u.channel.tracefile_size,
 515                                 msg.u.channel.tracefile_count, 0,
 516                                 msg.u.channel.monitor,
 517                                 msg.u.channel.live_timer_interval,
 518                                 msg.u.channel.is_live,
 519                                 NULL, NULL);
 520                 if (new_channel == NULL) {
 521                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 522                         goto end_nosignal;
 523                 }
 524                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 525                 switch (msg.u.channel.output) {
 526                 case LTTNG_EVENT_SPLICE:
 527                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 528                         break;
 529                 case LTTNG_EVENT_MMAP:
 530                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 531                         break;
 532                 default:
 533                         ERR("Channel output unknown %d", msg.u.channel.output);
 534                         goto end_nosignal;
 535                 }
 536
 537                 /* Translate and save channel type. */
 538                 switch (msg.u.channel.type) {
 539                 case CONSUMER_CHANNEL_TYPE_DATA:
 540                 case CONSUMER_CHANNEL_TYPE_METADATA:
 541                         new_channel->type = msg.u.channel.type;
 542                         break;
 543                 default:
 544                         abort();
 545                         goto end_nosignal;
 546                 };
 547
 548                 health_code_update();
 549
 550                 if (ctx->on_recv_channel != NULL) {
 551                         int ret_recv_channel =
 552                                         ctx->on_recv_channel(new_channel);
 553                         if (ret_recv_channel == 0) {
 554                                 ret_add_channel = consumer_add_channel(
 555                                                 new_channel, ctx);
 556                         } else if (ret_recv_channel < 0) {
 557                                 goto end_nosignal;
 558                         }
 559                 } else {
 560                         ret_add_channel =
 561                                         consumer_add_channel(new_channel, ctx);
 562                 }
 563                 if (msg.u.channel.type == CONSUMER_CHANNEL_TYPE_DATA &&
 564                                 !ret_add_channel) {
 565                         int monitor_start_ret;
 566
 567                         DBG("Consumer starting monitor timer");
 568                         consumer_timer_live_start(new_channel,
 569                                         msg.u.channel.live_timer_interval);
 570                         monitor_start_ret = consumer_timer_monitor_start(
 571                                         new_channel,
 572                                         msg.u.channel.monitor_timer_interval);
 573                         if (monitor_start_ret < 0) {
 574                                 ERR("Starting channel monitoring timer failed");
 575                                 goto end_nosignal;
 576                         }
 577                 }
 578
 579                 health_code_update();
 580
 581                 /* If we received an error in add_channel, we need to report it. */
 582                 if (ret_add_channel < 0) {
 583                         ret_send_status = consumer_send_status_msg(
 584                                         sock, ret_add_channel);
 585                         if (ret_send_status < 0) {
 586                                 goto error_fatal;
 587                         }
 588                         goto end_nosignal;
 589                 }
 590
 591                 goto end_nosignal;
 592         }
 593         case LTTNG_CONSUMER_ADD_STREAM:
 594         {
 595                 int fd;
 596                 struct lttng_pipe *stream_pipe;
 597                 struct lttng_consumer_stream *new_stream;
 598                 struct lttng_consumer_channel *channel;
 599                 int alloc_ret = 0;
 600                 int ret_send_status, ret_poll, ret_get_max_subbuf_size;
 601                 ssize_t ret_pipe_write, ret_recv;
 602
 603                 /*
 604                  * Get stream's channel reference. Needed when adding the stream to the
 605                  * global hash table.
 606                  */
 607                 channel = consumer_find_channel(msg.u.stream.channel_key);
 608                 if (!channel) {
 609                         /*
 610                          * We could not find the channel. Can happen if cpu hotplug
 611                          * happens while tearing down.
 612                          */
 613                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 614                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 615                 }
 616
 617                 health_code_update();
 618
 619                 /* First send a status message before receiving the fds. */
 620                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 621                 if (ret_send_status < 0) {
 622                         /* Somehow, the session daemon is not responding anymore. */
 623                         goto error_add_stream_fatal;
 624                 }
 625
 626                 health_code_update();
 627
 628                 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 629                         /* Channel was not found. */
 630                         goto error_add_stream_nosignal;
 631                 }
 632
 633                 /* Blocking call */
 634                 health_poll_entry();
 635                 ret_poll = lttng_consumer_poll_socket(consumer_sockpoll);
 636                 health_poll_exit();
 637                 if (ret_poll) {
 638                         goto error_add_stream_fatal;
 639                 }
 640
 641                 health_code_update();
 642
 643                 /* Get stream file descriptor from socket */
 644                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 645                 if (ret_recv != sizeof(fd)) {
 646                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 647                         ret_func = ret_recv;
 648                         goto end;
 649                 }
 650
 651                 health_code_update();
 652
 653                 /*
 654                  * Send status code to session daemon only if the recv works. If the
 655                  * above recv() failed, the session daemon is notified through the
 656                  * error socket and the teardown is eventually done.
 657                  */
 658                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 659                 if (ret_send_status < 0) {
 660                         /* Somehow, the session daemon is not responding anymore. */
 661                         goto error_add_stream_nosignal;
 662                 }
 663
 664                 health_code_update();
 665
 666                 pthread_mutex_lock(&channel->lock);
 667                 new_stream = consumer_stream_create(
 668                                 channel,
 669                                 channel->key,
 670                                 fd,
 671                                 channel->name,
 672                                 channel->relayd_id,
 673                                 channel->session_id,
 674                                 channel->trace_chunk,
 675                                 msg.u.stream.cpu,
 676                                 &alloc_ret,
 677                                 channel->type,
 678                                 channel->monitor);
 679                 if (new_stream == NULL) {
 680                         switch (alloc_ret) {
 681                         case -ENOMEM:
 682                         case -EINVAL:
 683                         default:
 684                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 685                                 break;
 686                         }
 687                         pthread_mutex_unlock(&channel->lock);
 688                         goto error_add_stream_nosignal;
 689                 }
 690
 691                 new_stream->wait_fd = fd;
 692                 ret_get_max_subbuf_size = kernctl_get_max_subbuf_size(
 693                                 new_stream->wait_fd, &new_stream->max_sb_size);
 694                 if (ret_get_max_subbuf_size < 0) {
 695                         pthread_mutex_unlock(&channel->lock);
 696                         ERR("Failed to get kernel maximal subbuffer size");
 697                         goto error_add_stream_nosignal;
 698                 }
 699
 700                 consumer_stream_update_channel_attributes(new_stream,
 701                                 channel);
 702
 703                 /*
 704                  * We've just assigned the channel to the stream so increment the
 705                  * refcount right now. We don't need to increment the refcount for
 706                  * streams in no monitor because we handle manually the cleanup of
 707                  * those. It is very important to make sure there is NO prior
 708                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 709                  */
 710                 if (channel->monitor) {
 711                         uatomic_inc(&new_stream->chan->refcount);
 712                 }
 713
 714                 /*
 715                  * The buffer flush is done on the session daemon side for the kernel
 716                  * so no need for the stream "hangup_flush_done" variable to be
 717                  * tracked. This is important for a kernel stream since we don't rely
 718                  * on the flush state of the stream to read data. It's not the case for
 719                  * user space tracing.
 720                  */
 721                 new_stream->hangup_flush_done = 0;
 722
 723                 health_code_update();
 724
 725                 pthread_mutex_lock(&new_stream->lock);
 726                 if (ctx->on_recv_stream) {
 727                         int ret_recv_stream = ctx->on_recv_stream(new_stream);
 728                         if (ret_recv_stream < 0) {
 729                                 pthread_mutex_unlock(&new_stream->lock);
 730                                 pthread_mutex_unlock(&channel->lock);
 731                                 consumer_stream_free(new_stream);
 732                                 goto error_add_stream_nosignal;
 733                         }
 734                 }
 735                 health_code_update();
 736
 737                 if (new_stream->metadata_flag) {
 738                         channel->metadata_stream = new_stream;
 739                 }
 740
 741                 /* Do not monitor this stream. */
 742                 if (!channel->monitor) {
 743                         DBG("Kernel consumer add stream %s in no monitor mode with "
 744                                         "relayd id %" PRIu64, new_stream->name,
 745                                         new_stream->net_seq_idx);
 746                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 747                         pthread_mutex_unlock(&new_stream->lock);
 748                         pthread_mutex_unlock(&channel->lock);
 749                         goto end_add_stream;
 750                 }
 751
 752                 /* Send stream to relayd if the stream has an ID. */
 753                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 754                         int ret_send_relayd_stream;
 755
 756                         ret_send_relayd_stream = consumer_send_relayd_stream(
 757                                         new_stream, new_stream->chan->pathname);
 758                         if (ret_send_relayd_stream < 0) {
 759                                 pthread_mutex_unlock(&new_stream->lock);
 760                                 pthread_mutex_unlock(&channel->lock);
 761                                 consumer_stream_free(new_stream);
 762                                 goto error_add_stream_nosignal;
 763                         }
 764
 765                         /*
 766                          * If adding an extra stream to an already
 767                          * existing channel (e.g. cpu hotplug), we need
 768                          * to send the "streams_sent" command to relayd.
 769                          */
 770                         if (channel->streams_sent_to_relayd) {
 771                                 int ret_send_relayd_streams_sent;
 772
 773                                 ret_send_relayd_streams_sent =
 774                                                 consumer_send_relayd_streams_sent(
 775                                                                 new_stream->net_seq_idx);
 776                                 if (ret_send_relayd_streams_sent < 0) {
 777                                         pthread_mutex_unlock(&new_stream->lock);
 778                                         pthread_mutex_unlock(&channel->lock);
 779                                         goto error_add_stream_nosignal;
 780                                 }
 781                         }
 782                 }
 783                 pthread_mutex_unlock(&new_stream->lock);
 784                 pthread_mutex_unlock(&channel->lock);
 785
 786                 /* Get the right pipe where the stream will be sent. */
 787                 if (new_stream->metadata_flag) {
 788                         consumer_add_metadata_stream(new_stream);
 789                         stream_pipe = ctx->consumer_metadata_pipe;
 790                 } else {
 791                         consumer_add_data_stream(new_stream);
 792                         stream_pipe = ctx->consumer_data_pipe;
 793                 }
 794
 795                 /* Visible to other threads */
 796                 new_stream->globally_visible = 1;
 797
 798                 health_code_update();
 799
 800                 ret_pipe_write = lttng_pipe_write(
 801                                 stream_pipe, &new_stream, sizeof(new_stream));
 802                 if (ret_pipe_write < 0) {
 803                         ERR("Consumer write %s stream to pipe %d",
 804                                         new_stream->metadata_flag ? "metadata" : "data",
 805                                         lttng_pipe_get_writefd(stream_pipe));
 806                         if (new_stream->metadata_flag) {
 807                                 consumer_del_stream_for_metadata(new_stream);
 808                         } else {
 809                                 consumer_del_stream_for_data(new_stream);
 810                         }
 811                         goto error_add_stream_nosignal;
 812                 }
 813
 814                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
 815                                 new_stream->name, fd, new_stream->chan->pathname, new_stream->relayd_stream_id);
 816 end_add_stream:
 817                 break;
 818 error_add_stream_nosignal:
 819                 goto end_nosignal;
 820 error_add_stream_fatal:
 821                 goto error_fatal;
 822         }
 823         case LTTNG_CONSUMER_STREAMS_SENT:
 824         {
 825                 struct lttng_consumer_channel *channel;
 826                 int ret_send_status;
 827
 828                 /*
 829                  * Get stream's channel reference. Needed when adding the stream to the
 830                  * global hash table.
 831                  */
 832                 channel = consumer_find_channel(msg.u.sent_streams.channel_key);
 833                 if (!channel) {
 834                         /*
 835                          * We could not find the channel. Can happen if cpu hotplug
 836                          * happens while tearing down.
 837                          */
 838                         ERR("Unable to find channel key %" PRIu64,
 839                                         msg.u.sent_streams.channel_key);
 840                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 841                 }
 842
 843                 health_code_update();
 844
 845                 /*
 846                  * Send status code to session daemon.
 847                  */
 848                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 849                 if (ret_send_status < 0 ||
 850                                 ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 851                         /* Somehow, the session daemon is not responding anymore. */
 852                         goto error_streams_sent_nosignal;
 853                 }
 854
 855                 health_code_update();
 856
 857                 /*
 858                  * We should not send this message if we don't monitor the
 859                  * streams in this channel.
 860                  */
 861                 if (!channel->monitor) {
 862                         goto end_error_streams_sent;
 863                 }
 864
 865                 health_code_update();
 866                 /* Send stream to relayd if the stream has an ID. */
 867                 if (msg.u.sent_streams.net_seq_idx != (uint64_t) -1ULL) {
 868                         int ret_send_relay_streams;
 869
 870                         ret_send_relay_streams = consumer_send_relayd_streams_sent(
 871                                         msg.u.sent_streams.net_seq_idx);
 872                         if (ret_send_relay_streams < 0) {
 873                                 goto error_streams_sent_nosignal;
 874                         }
 875                         channel->streams_sent_to_relayd = true;
 876                 }
 877 end_error_streams_sent:
 878                 break;
 879 error_streams_sent_nosignal:
 880                 goto end_nosignal;
 881         }
 882         case LTTNG_CONSUMER_UPDATE_STREAM:
 883         {
 884                 rcu_read_unlock();
 885                 return -ENOSYS;
 886         }
 887         case LTTNG_CONSUMER_DESTROY_RELAYD:
 888         {
 889                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 890                 struct consumer_relayd_sock_pair *relayd;
 891                 int ret_send_status;
 892
 893                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 894
 895                 /* Get relayd reference if exists. */
 896                 relayd = consumer_find_relayd(index);
 897                 if (relayd == NULL) {
 898                         DBG("Unable to find relayd %" PRIu64, index);
 899                         ret_code = LTTCOMM_CONSUMERD_RELAYD_FAIL;
 900                 }
 901
 902                 /*
 903                  * Each relayd socket pair has a refcount of stream attached to it
 904                  * which tells if the relayd is still active or not depending on the
 905                  * refcount value.
 906                  *
 907                  * This will set the destroy flag of the relayd object and destroy it
 908                  * if the refcount reaches zero when called.
 909                  *
 910                  * The destroy can happen either here or when a stream fd hangs up.
 911                  */
 912                 if (relayd) {
 913                         consumer_flag_relayd_for_destroy(relayd);
 914                 }
 915
 916                 health_code_update();
 917
 918                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 919                 if (ret_send_status < 0) {
 920                         /* Somehow, the session daemon is not responding anymore. */
 921                         goto error_fatal;
 922                 }
 923
 924                 goto end_nosignal;
 925         }
 926         case LTTNG_CONSUMER_DATA_PENDING:
 927         {
 928                 int32_t ret_data_pending;
 929                 uint64_t id = msg.u.data_pending.session_id;
 930                 ssize_t ret_send;
 931
 932                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 933
 934                 ret_data_pending = consumer_data_pending(id);
 935
 936                 health_code_update();
 937
 938                 /* Send back returned value to session daemon */
 939                 ret_send = lttcomm_send_unix_sock(sock, &ret_data_pending,
 940                                 sizeof(ret_data_pending));
 941                 if (ret_send < 0) {
 942                         PERROR("send data pending ret code");
 943                         goto error_fatal;
 944                 }
 945
 946                 /*
 947                  * No need to send back a status message since the data pending
 948                  * returned value is the response.
 949                  */
 950                 break;
 951         }
 952         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 953         {
 954                 struct lttng_consumer_channel *channel;
 955                 uint64_t key = msg.u.snapshot_channel.key;
 956                 int ret_send_status;
 957
 958                 channel = consumer_find_channel(key);
 959                 if (!channel) {
 960                         ERR("Channel %" PRIu64 " not found", key);
 961                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 962                 } else {
 963                         pthread_mutex_lock(&channel->lock);
 964                         if (msg.u.snapshot_channel.metadata == 1) {
 965                                 int ret_snapshot;
 966
 967                                 ret_snapshot = lttng_kconsumer_snapshot_metadata(
 968                                                 channel, key,
 969                                                 msg.u.snapshot_channel.pathname,
 970                                                 msg.u.snapshot_channel.relayd_id,
 971                                                 ctx);
 972                                 if (ret_snapshot < 0) {
 973                                         ERR("Snapshot metadata failed");
 974                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 975                                 }
 976                         } else {
 977                                 int ret_snapshot;
 978
 979                                 ret_snapshot = lttng_kconsumer_snapshot_channel(
 980                                                 channel, key,
 981                                                 msg.u.snapshot_channel.pathname,
 982                                                 msg.u.snapshot_channel.relayd_id,
 983                                                 msg.u.snapshot_channel
 984                                                                 .nb_packets_per_stream,
 985                                                 ctx);
 986                                 if (ret_snapshot < 0) {
 987                                         ERR("Snapshot channel failed");
 988                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 989                                 }
 990                         }
 991                         pthread_mutex_unlock(&channel->lock);
 992                 }
 993                 health_code_update();
 994
 995                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 996                 if (ret_send_status < 0) {
 997                         /* Somehow, the session daemon is not responding anymore. */
 998                         goto end_nosignal;
 999                 }
1000                 break;
1001         }
1002         case LTTNG_CONSUMER_DESTROY_CHANNEL:
1003         {
1004                 uint64_t key = msg.u.destroy_channel.key;
1005                 struct lttng_consumer_channel *channel;
1006                 int ret_send_status;
1007
1008                 channel = consumer_find_channel(key);
1009                 if (!channel) {
1010                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
1011                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1012                 }
1013
1014                 health_code_update();
1015
1016                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1017                 if (ret_send_status < 0) {
1018                         /* Somehow, the session daemon is not responding anymore. */
1019                         goto end_destroy_channel;
1020                 }
1021
1022                 health_code_update();
1023
1024                 /* Stop right now if no channel was found. */
1025                 if (!channel) {
1026                         goto end_destroy_channel;
1027                 }
1028
1029                 /*
1030                  * This command should ONLY be issued for channel with streams set in
1031                  * no monitor mode.
1032                  */
1033                 LTTNG_ASSERT(!channel->monitor);
1034
1035                 /*
1036                  * The refcount should ALWAYS be 0 in the case of a channel in no
1037                  * monitor mode.
1038                  */
1039                 LTTNG_ASSERT(!uatomic_sub_return(&channel->refcount, 1));
1040
1041                 consumer_del_channel(channel);
1042 end_destroy_channel:
1043                 goto end_nosignal;
1044         }
1045         case LTTNG_CONSUMER_DISCARDED_EVENTS:
1046         {
1047                 ssize_t ret;
1048                 uint64_t count;
1049                 struct lttng_consumer_channel *channel;
1050                 uint64_t id = msg.u.discarded_events.session_id;
1051                 uint64_t key = msg.u.discarded_events.channel_key;
1052
1053                 DBG("Kernel consumer discarded events command for session id %"
1054                                 PRIu64 ", channel key %" PRIu64, id, key);
1055
1056                 channel = consumer_find_channel(key);
1057                 if (!channel) {
1058                         ERR("Kernel consumer discarded events channel %"
1059                                         PRIu64 " not found", key);
1060                         count = 0;
1061                 } else {
1062                         count = channel->discarded_events;
1063                 }
1064
1065                 health_code_update();
1066
1067                 /* Send back returned value to session daemon */
1068                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1069                 if (ret < 0) {
1070                         PERROR("send discarded events");
1071                         goto error_fatal;
1072                 }
1073
1074                 break;
1075         }
1076         case LTTNG_CONSUMER_LOST_PACKETS:
1077         {
1078                 ssize_t ret;
1079                 uint64_t count;
1080                 struct lttng_consumer_channel *channel;
1081                 uint64_t id = msg.u.lost_packets.session_id;
1082                 uint64_t key = msg.u.lost_packets.channel_key;
1083
1084                 DBG("Kernel consumer lost packets command for session id %"
1085                                 PRIu64 ", channel key %" PRIu64, id, key);
1086
1087                 channel = consumer_find_channel(key);
1088                 if (!channel) {
1089                         ERR("Kernel consumer lost packets channel %"
1090                                         PRIu64 " not found", key);
1091                         count = 0;
1092                 } else {
1093                         count = channel->lost_packets;
1094                 }
1095
1096                 health_code_update();
1097
1098                 /* Send back returned value to session daemon */
1099                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1100                 if (ret < 0) {
1101                         PERROR("send lost packets");
1102                         goto error_fatal;
1103                 }
1104
1105                 break;
1106         }
1107         case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
1108         {
1109                 int channel_monitor_pipe;
1110                 int ret_send_status, ret_set_channel_monitor_pipe;
1111                 ssize_t ret_recv;
1112
1113                 ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1114                 /* Successfully received the command's type. */
1115                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1116                 if (ret_send_status < 0) {
1117                         goto error_fatal;
1118                 }
1119
1120                 ret_recv = lttcomm_recv_fds_unix_sock(
1121                                 sock, &channel_monitor_pipe, 1);
1122                 if (ret_recv != sizeof(channel_monitor_pipe)) {
1123                         ERR("Failed to receive channel monitor pipe");
1124                         goto error_fatal;
1125                 }
1126
1127                 DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
1128                 ret_set_channel_monitor_pipe =
1129                                 consumer_timer_thread_set_channel_monitor_pipe(
1130                                                 channel_monitor_pipe);
1131                 if (!ret_set_channel_monitor_pipe) {
1132                         int flags;
1133                         int ret_fcntl;
1134
1135                         ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1136                         /* Set the pipe as non-blocking. */
1137                         ret_fcntl = fcntl(channel_monitor_pipe, F_GETFL, 0);
1138                         if (ret_fcntl == -1) {
1139                                 PERROR("fcntl get flags of the channel monitoring pipe");
1140                                 goto error_fatal;
1141                         }
1142                         flags = ret_fcntl;
1143
1144                         ret_fcntl = fcntl(channel_monitor_pipe, F_SETFL,
1145                                         flags | O_NONBLOCK);
1146                         if (ret_fcntl == -1) {
1147                                 PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
1148                                 goto error_fatal;
1149                         }
1150                         DBG("Channel monitor pipe set as non-blocking");
1151                 } else {
1152                         ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
1153                 }
1154                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1155                 if (ret_send_status < 0) {
1156                         goto error_fatal;
1157                 }
1158                 break;
1159         }
1160         case LTTNG_CONSUMER_ROTATE_CHANNEL:
1161         {
1162                 struct lttng_consumer_channel *channel;
1163                 uint64_t key = msg.u.rotate_channel.key;
1164                 int ret_send_status;
1165
1166                 DBG("Consumer rotate channel %" PRIu64, key);
1167
1168                 channel = consumer_find_channel(key);
1169                 if (!channel) {
1170                         ERR("Channel %" PRIu64 " not found", key);
1171                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1172                 } else {
1173                         /*
1174                          * Sample the rotate position of all the streams in this channel.
1175                          */
1176                         int ret_rotate_channel;
1177
1178                         ret_rotate_channel = lttng_consumer_rotate_channel(
1179                                         channel, key,
1180                                         msg.u.rotate_channel.relayd_id,
1181                                         msg.u.rotate_channel.metadata, ctx);
1182                         if (ret_rotate_channel < 0) {
1183                                 ERR("Rotate channel failed");
1184                                 ret_code = LTTCOMM_CONSUMERD_ROTATION_FAIL;
1185                         }
1186
1187                         health_code_update();
1188                 }
1189
1190                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1191                 if (ret_send_status < 0) {
1192                         /* Somehow, the session daemon is not responding anymore. */
1193                         goto error_rotate_channel;
1194                 }
1195                 if (channel) {
1196                         /* Rotate the streams that are ready right now. */
1197                         int ret_rotate;
1198
1199                         ret_rotate = lttng_consumer_rotate_ready_streams(
1200                                         channel, key, ctx);
1201                         if (ret_rotate < 0) {
1202                                 ERR("Rotate ready streams failed");
1203                         }
1204                 }
1205                 break;
1206 error_rotate_channel:
1207                 goto end_nosignal;
1208         }
1209         case LTTNG_CONSUMER_CLEAR_CHANNEL:
1210         {
1211                 struct lttng_consumer_channel *channel;
1212                 uint64_t key = msg.u.clear_channel.key;
1213                 int ret_send_status;
1214
1215                 channel = consumer_find_channel(key);
1216                 if (!channel) {
1217                         DBG("Channel %" PRIu64 " not found", key);
1218                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1219                 } else {
1220                         int ret_clear_channel;
1221
1222                         ret_clear_channel =
1223                                         lttng_consumer_clear_channel(channel);
1224                         if (ret_clear_channel) {
1225                                 ERR("Clear channel failed");
1226                                 ret_code = ret_clear_channel;
1227                         }
1228
1229                         health_code_update();
1230                 }
1231
1232                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1233                 if (ret_send_status < 0) {
1234                         /* Somehow, the session daemon is not responding anymore. */
1235                         goto end_nosignal;
1236                 }
1237
1238                 break;
1239         }
1240         case LTTNG_CONSUMER_INIT:
1241         {
1242                 int ret_send_status;
1243
1244                 ret_code = lttng_consumer_init_command(ctx,
1245                                 msg.u.init.sessiond_uuid);
1246                 health_code_update();
1247                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1248                 if (ret_send_status < 0) {
1249                         /* Somehow, the session daemon is not responding anymore. */
1250                         goto end_nosignal;
1251                 }
1252                 break;
1253         }
1254         case LTTNG_CONSUMER_CREATE_TRACE_CHUNK:
1255         {
1256                 const struct lttng_credentials credentials = {
1257                         .uid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.uid),
1258                         .gid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.gid),
1259                 };
1260                 const bool is_local_trace =
1261                                 !msg.u.create_trace_chunk.relayd_id.is_set;
1262                 const uint64_t relayd_id =
1263                                 msg.u.create_trace_chunk.relayd_id.value;
1264                 const char *chunk_override_name =
1265                                 *msg.u.create_trace_chunk.override_name ?
1266                                         msg.u.create_trace_chunk.override_name :
1267                                         NULL;
1268                 struct lttng_directory_handle *chunk_directory_handle = NULL;
1269
1270                 /*
1271                  * The session daemon will only provide a chunk directory file
1272                  * descriptor for local traces.
1273                  */
1274                 if (is_local_trace) {
1275                         int chunk_dirfd;
1276                         int ret_send_status;
1277                         ssize_t ret_recv;
1278
1279                         /* Acnowledge the reception of the command. */
1280                         ret_send_status = consumer_send_status_msg(
1281                                         sock, LTTCOMM_CONSUMERD_SUCCESS);
1282                         if (ret_send_status < 0) {
1283                                 /* Somehow, the session daemon is not responding anymore. */
1284                                 goto end_nosignal;
1285                         }
1286
1287                         ret_recv = lttcomm_recv_fds_unix_sock(
1288                                         sock, &chunk_dirfd, 1);
1289                         if (ret_recv != sizeof(chunk_dirfd)) {
1290                                 ERR("Failed to receive trace chunk directory file descriptor");
1291                                 goto error_fatal;
1292                         }
1293
1294                         DBG("Received trace chunk directory fd (%d)",
1295                                         chunk_dirfd);
1296                         chunk_directory_handle = lttng_directory_handle_create_from_dirfd(
1297                                         chunk_dirfd);
1298                         if (!chunk_directory_handle) {
1299                                 ERR("Failed to initialize chunk directory handle from directory file descriptor");
1300                                 if (close(chunk_dirfd)) {
1301                                         PERROR("Failed to close chunk directory file descriptor");
1302                                 }
1303                                 goto error_fatal;
1304                         }
1305                 }
1306
1307                 ret_code = lttng_consumer_create_trace_chunk(
1308                                 !is_local_trace ? &relayd_id : NULL,
1309                                 msg.u.create_trace_chunk.session_id,
1310                                 msg.u.create_trace_chunk.chunk_id,
1311                                 (time_t) msg.u.create_trace_chunk
1312                                                 .creation_timestamp,
1313                                 chunk_override_name,
1314                                 msg.u.create_trace_chunk.credentials.is_set ?
1315                                                 &credentials :
1316                                                 NULL,
1317                                 chunk_directory_handle);
1318                 lttng_directory_handle_put(chunk_directory_handle);
1319                 goto end_msg_sessiond;
1320         }
1321         case LTTNG_CONSUMER_CLOSE_TRACE_CHUNK:
1322         {
1323                 enum lttng_trace_chunk_command_type close_command =
1324                                 msg.u.close_trace_chunk.close_command.value;
1325                 const uint64_t relayd_id =
1326                                 msg.u.close_trace_chunk.relayd_id.value;
1327                 struct lttcomm_consumer_close_trace_chunk_reply reply;
1328                 char path[LTTNG_PATH_MAX];
1329                 ssize_t ret_send;
1330
1331                 ret_code = lttng_consumer_close_trace_chunk(
1332                                 msg.u.close_trace_chunk.relayd_id.is_set ?
1333                                                 &relayd_id :
1334                                                 NULL,
1335                                 msg.u.close_trace_chunk.session_id,
1336                                 msg.u.close_trace_chunk.chunk_id,
1337                                 (time_t) msg.u.close_trace_chunk.close_timestamp,
1338                                 msg.u.close_trace_chunk.close_command.is_set ?
1339                                                 &close_command :
1340                                                 NULL, path);
1341                 reply.ret_code = ret_code;
1342                 reply.path_length = strlen(path) + 1;
1343                 ret_send = lttcomm_send_unix_sock(sock, &reply, sizeof(reply));
1344                 if (ret_send != sizeof(reply)) {
1345                         goto error_fatal;
1346                 }
1347                 ret_send = lttcomm_send_unix_sock(
1348                                 sock, path, reply.path_length);
1349                 if (ret_send != reply.path_length) {
1350                         goto error_fatal;
1351                 }
1352                 goto end_nosignal;
1353         }
1354         case LTTNG_CONSUMER_TRACE_CHUNK_EXISTS:
1355         {
1356                 const uint64_t relayd_id =
1357                                 msg.u.trace_chunk_exists.relayd_id.value;
1358
1359                 ret_code = lttng_consumer_trace_chunk_exists(
1360                                 msg.u.trace_chunk_exists.relayd_id.is_set ?
1361                                                 &relayd_id : NULL,
1362                                 msg.u.trace_chunk_exists.session_id,
1363                                 msg.u.trace_chunk_exists.chunk_id);
1364                 goto end_msg_sessiond;
1365         }
1366         case LTTNG_CONSUMER_OPEN_CHANNEL_PACKETS:
1367         {
1368                 const uint64_t key = msg.u.open_channel_packets.key;
1369                 struct lttng_consumer_channel *channel =
1370                                 consumer_find_channel(key);
1371
1372                 if (channel) {
1373                         pthread_mutex_lock(&channel->lock);
1374                         ret_code = lttng_consumer_open_channel_packets(channel);
1375                         pthread_mutex_unlock(&channel->lock);
1376                 } else {
1377                         WARN("Channel %" PRIu64 " not found", key);
1378                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1379                 }
1380
1381                 health_code_update();
1382                 goto end_msg_sessiond;
1383         }
1384         default:
1385                 goto end_nosignal;
1386         }
1387
1388 end_nosignal:
1389         /*
1390          * Return 1 to indicate success since the 0 value can be a socket
1391          * shutdown during the recv() or send() call.
1392          */
1393         ret_func = 1;
1394         goto end;
1395 error_fatal:
1396         /* This will issue a consumer stop. */
1397         ret_func = -1;
1398         goto end;
1399 end_msg_sessiond:
1400         /*
1401          * The returned value here is not useful since either way we'll return 1 to
1402          * the caller because the session daemon socket management is done
1403          * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1404          */
1405         {
1406                 int ret_send_status;
1407
1408                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1409                 if (ret_send_status < 0) {
1410                         goto error_fatal;
1411                 }
1412         }
1413
1414         ret_func = 1;
1415
1416 end:
1417         health_code_update();
1418         rcu_read_unlock();
1419         return ret_func;
1420 }
1421
1422 /*
1423  * Sync metadata meaning request them to the session daemon and snapshot to the
1424  * metadata thread can consumer them.
1425  *
1426  * Metadata stream lock MUST be acquired.
1427  */
1428 enum sync_metadata_status lttng_kconsumer_sync_metadata(
1429                 struct lttng_consumer_stream *metadata)
1430 {
1431         int ret;
1432         enum sync_metadata_status status;
1433
1434         LTTNG_ASSERT(metadata);
1435
1436         ret = kernctl_buffer_flush(metadata->wait_fd);
1437         if (ret < 0) {
1438                 ERR("Failed to flush kernel stream");
1439                 status = SYNC_METADATA_STATUS_ERROR;
1440                 goto end;
1441         }
1442
1443         ret = kernctl_snapshot(metadata->wait_fd);
1444         if (ret < 0) {
1445                 if (errno == EAGAIN) {
1446                         /* No new metadata, exit. */
1447                         DBG("Sync metadata, no new kernel metadata");
1448                         status = SYNC_METADATA_STATUS_NO_DATA;
1449                 } else {
1450                         ERR("Sync metadata, taking kernel snapshot failed.");
1451                         status = SYNC_METADATA_STATUS_ERROR;
1452                 }
1453         } else {
1454                 status = SYNC_METADATA_STATUS_NEW_DATA;
1455         }
1456
1457 end:
1458         return status;
1459 }
1460
1461 static
1462 int extract_common_subbuffer_info(struct lttng_consumer_stream *stream,
1463                 struct stream_subbuffer *subbuf)
1464 {
1465         int ret;
1466
1467         ret = kernctl_get_subbuf_size(
1468                         stream->wait_fd, &subbuf->info.data.subbuf_size);
1469         if (ret) {
1470                 goto end;
1471         }
1472
1473         ret = kernctl_get_padded_subbuf_size(
1474                         stream->wait_fd, &subbuf->info.data.padded_subbuf_size);
1475         if (ret) {
1476                 goto end;
1477         }
1478
1479 end:
1480         return ret;
1481 }
1482
1483 static
1484 int extract_metadata_subbuffer_info(struct lttng_consumer_stream *stream,
1485                 struct stream_subbuffer *subbuf)
1486 {
1487         int ret;
1488
1489         ret = extract_common_subbuffer_info(stream, subbuf);
1490         if (ret) {
1491                 goto end;
1492         }
1493
1494         ret = kernctl_get_metadata_version(
1495                         stream->wait_fd, &subbuf->info.metadata.version);
1496         if (ret) {
1497                 goto end;
1498         }
1499
1500 end:
1501         return ret;
1502 }
1503
1504 static
1505 int extract_data_subbuffer_info(struct lttng_consumer_stream *stream,
1506                 struct stream_subbuffer *subbuf)
1507 {
1508         int ret;
1509
1510         ret = extract_common_subbuffer_info(stream, subbuf);
1511         if (ret) {
1512                 goto end;
1513         }
1514
1515         ret = kernctl_get_packet_size(
1516                         stream->wait_fd, &subbuf->info.data.packet_size);
1517         if (ret < 0) {
1518                 PERROR("Failed to get sub-buffer packet size");
1519                 goto end;
1520         }
1521
1522         ret = kernctl_get_content_size(
1523                         stream->wait_fd, &subbuf->info.data.content_size);
1524         if (ret < 0) {
1525                 PERROR("Failed to get sub-buffer content size");
1526                 goto end;
1527         }
1528
1529         ret = kernctl_get_timestamp_begin(
1530                         stream->wait_fd, &subbuf->info.data.timestamp_begin);
1531         if (ret < 0) {
1532                 PERROR("Failed to get sub-buffer begin timestamp");
1533                 goto end;
1534         }
1535
1536         ret = kernctl_get_timestamp_end(
1537                         stream->wait_fd, &subbuf->info.data.timestamp_end);
1538         if (ret < 0) {
1539                 PERROR("Failed to get sub-buffer end timestamp");
1540                 goto end;
1541         }
1542
1543         ret = kernctl_get_events_discarded(
1544                         stream->wait_fd, &subbuf->info.data.events_discarded);
1545         if (ret) {
1546                 PERROR("Failed to get sub-buffer events discarded count");
1547                 goto end;
1548         }
1549
1550         ret = kernctl_get_sequence_number(stream->wait_fd,
1551                         &subbuf->info.data.sequence_number.value);
1552         if (ret) {
1553                 /* May not be supported by older LTTng-modules. */
1554                 if (ret != -ENOTTY) {
1555                         PERROR("Failed to get sub-buffer sequence number");
1556                         goto end;
1557                 }
1558         } else {
1559                 subbuf->info.data.sequence_number.is_set = true;
1560         }
1561
1562         ret = kernctl_get_stream_id(
1563                         stream->wait_fd, &subbuf->info.data.stream_id);
1564         if (ret < 0) {
1565                 PERROR("Failed to get stream id");
1566                 goto end;
1567         }
1568
1569         ret = kernctl_get_instance_id(stream->wait_fd,
1570                         &subbuf->info.data.stream_instance_id.value);
1571         if (ret) {
1572                 /* May not be supported by older LTTng-modules. */
1573                 if (ret != -ENOTTY) {
1574                         PERROR("Failed to get stream instance id");
1575                         goto end;
1576                 }
1577         } else {
1578                 subbuf->info.data.stream_instance_id.is_set = true;
1579         }
1580 end:
1581         return ret;
1582 }
1583
1584 static
1585 enum get_next_subbuffer_status get_subbuffer_common(
1586                 struct lttng_consumer_stream *stream,
1587                 struct stream_subbuffer *subbuffer)
1588 {
1589         int ret;
1590         enum get_next_subbuffer_status status;
1591
1592         ret = kernctl_get_next_subbuf(stream->wait_fd);
1593         switch (ret) {
1594         case 0:
1595                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1596                 break;
1597         case -ENODATA:
1598                 case -EAGAIN:
1599                 /*
1600                  * The caller only expects -ENODATA when there is no data to
1601                  * read, but the kernel tracer returns -EAGAIN when there is
1602                  * currently no data for a non-finalized stream, and -ENODATA
1603                  * when there is no data for a finalized stream. Those can be
1604                  * combined into a -ENODATA return value.
1605                  */
1606                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1607                 goto end;
1608         default:
1609                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1610                 goto end;
1611         }
1612
1613         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1614                 stream, subbuffer);
1615         if (ret) {
1616                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1617         }
1618 end:
1619         return status;
1620 }
1621
1622 static
1623 enum get_next_subbuffer_status get_next_subbuffer_splice(
1624                 struct lttng_consumer_stream *stream,
1625                 struct stream_subbuffer *subbuffer)
1626 {
1627         const enum get_next_subbuffer_status status =
1628                         get_subbuffer_common(stream, subbuffer);
1629
1630         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1631                 goto end;
1632         }
1633
1634         subbuffer->buffer.fd = stream->wait_fd;
1635 end:
1636         return status;
1637 }
1638
1639 static
1640 enum get_next_subbuffer_status get_next_subbuffer_mmap(
1641                 struct lttng_consumer_stream *stream,
1642                 struct stream_subbuffer *subbuffer)
1643 {
1644         int ret;
1645         enum get_next_subbuffer_status status;
1646         const char *addr;
1647
1648         status = get_subbuffer_common(stream, subbuffer);
1649         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1650                 goto end;
1651         }
1652
1653         ret = get_current_subbuf_addr(stream, &addr);
1654         if (ret) {
1655                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1656                 goto end;
1657         }
1658
1659         subbuffer->buffer.buffer = lttng_buffer_view_init(
1660                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1661 end:
1662         return status;
1663 }
1664
1665 static
1666 enum get_next_subbuffer_status get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
1667                 struct stream_subbuffer *subbuffer)
1668 {
1669         int ret;
1670         const char *addr;
1671         bool coherent;
1672         enum get_next_subbuffer_status status;
1673
1674         ret = kernctl_get_next_subbuf_metadata_check(stream->wait_fd,
1675                         &coherent);
1676         if (ret) {
1677                 goto end;
1678         }
1679
1680         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1681                         stream, subbuffer);
1682         if (ret) {
1683                 goto end;
1684         }
1685
1686         LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
1687
1688         ret = get_current_subbuf_addr(stream, &addr);
1689         if (ret) {
1690                 goto end;
1691         }
1692
1693         subbuffer->buffer.buffer = lttng_buffer_view_init(
1694                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1695         DBG("Got metadata packet with padded_subbuf_size = %lu, coherent = %s",
1696                         subbuffer->info.metadata.padded_subbuf_size,
1697                         coherent ? "true" : "false");
1698 end:
1699         /*
1700          * The caller only expects -ENODATA when there is no data to read, but
1701          * the kernel tracer returns -EAGAIN when there is currently no data
1702          * for a non-finalized stream, and -ENODATA when there is no data for a
1703          * finalized stream. Those can be combined into a -ENODATA return value.
1704          */
1705         switch (ret) {
1706         case 0:
1707                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1708                 break;
1709         case -ENODATA:
1710         case -EAGAIN:
1711                 /*
1712                  * The caller only expects -ENODATA when there is no data to
1713                  * read, but the kernel tracer returns -EAGAIN when there is
1714                  * currently no data for a non-finalized stream, and -ENODATA
1715                  * when there is no data for a finalized stream. Those can be
1716                  * combined into a -ENODATA return value.
1717                  */
1718                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1719                 break;
1720         default:
1721                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1722                 break;
1723         }
1724
1725         return status;
1726 }
1727
1728 static
1729 int put_next_subbuffer(struct lttng_consumer_stream *stream,
1730                 struct stream_subbuffer *subbuffer)
1731 {
1732         const int ret = kernctl_put_next_subbuf(stream->wait_fd);
1733
1734         if (ret) {
1735                 if (ret == -EFAULT) {
1736                         PERROR("Error in unreserving sub buffer");
1737                 } else if (ret == -EIO) {
1738                         /* Should never happen with newer LTTng versions */
1739                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted");
1740                 }
1741         }
1742
1743         return ret;
1744 }
1745
1746 static
1747 bool is_get_next_check_metadata_available(int tracer_fd)
1748 {
1749         const int ret = kernctl_get_next_subbuf_metadata_check(tracer_fd, NULL);
1750         const bool available = ret != -ENOTTY;
1751
1752         if (ret == 0) {
1753                 /* get succeeded, make sure to put the subbuffer. */
1754                 kernctl_put_subbuf(tracer_fd);
1755         }
1756
1757         return available;
1758 }
1759
1760 static
1761 int signal_metadata(struct lttng_consumer_stream *stream,
1762                 struct lttng_consumer_local_data *ctx)
1763 {
1764         ASSERT_LOCKED(stream->metadata_rdv_lock);
1765         return pthread_cond_broadcast(&stream->metadata_rdv) ? -errno : 0;
1766 }
1767
1768 static
1769 int lttng_kconsumer_set_stream_ops(
1770                 struct lttng_consumer_stream *stream)
1771 {
1772         int ret = 0;
1773
1774         if (stream->metadata_flag && stream->chan->is_live) {
1775                 DBG("Attempting to enable metadata bucketization for live consumers");
1776                 if (is_get_next_check_metadata_available(stream->wait_fd)) {
1777                         DBG("Kernel tracer supports get_next_subbuffer_metadata_check, metadata will be accumulated until a coherent state is reached");
1778                         stream->read_subbuffer_ops.get_next_subbuffer =
1779                                         get_next_subbuffer_metadata_check;
1780                         ret = consumer_stream_enable_metadata_bucketization(
1781                                         stream);
1782                         if (ret) {
1783                                 goto end;
1784                         }
1785                 } else {
1786                         /*
1787                          * The kernel tracer version is too old to indicate
1788                          * when the metadata stream has reached a "coherent"
1789                          * (parseable) point.
1790                          *
1791                          * This means that a live viewer may see an incoherent
1792                          * sequence of metadata and fail to parse it.
1793                          */
1794                         WARN("Kernel tracer does not support get_next_subbuffer_metadata_check which may cause live clients to fail to parse the metadata stream");
1795                         metadata_bucket_destroy(stream->metadata_bucket);
1796                         stream->metadata_bucket = NULL;
1797                 }
1798
1799                 stream->read_subbuffer_ops.on_sleep = signal_metadata;
1800         }
1801
1802         if (!stream->read_subbuffer_ops.get_next_subbuffer) {
1803                 if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
1804                         stream->read_subbuffer_ops.get_next_subbuffer =
1805                                         get_next_subbuffer_mmap;
1806                 } else {
1807                         stream->read_subbuffer_ops.get_next_subbuffer =
1808                                         get_next_subbuffer_splice;
1809                 }
1810         }
1811
1812         if (stream->metadata_flag) {
1813                 stream->read_subbuffer_ops.extract_subbuffer_info =
1814                                 extract_metadata_subbuffer_info;
1815         } else {
1816                 stream->read_subbuffer_ops.extract_subbuffer_info =
1817                                 extract_data_subbuffer_info;
1818                 if (stream->chan->is_live) {
1819                         stream->read_subbuffer_ops.send_live_beacon =
1820                                         consumer_flush_kernel_index;
1821                 }
1822         }
1823
1824         stream->read_subbuffer_ops.put_next_subbuffer = put_next_subbuffer;
1825 end:
1826         return ret;
1827 }
1828
1829 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1830 {
1831         int ret;
1832
1833         LTTNG_ASSERT(stream);
1834
1835         /*
1836          * Don't create anything if this is set for streaming or if there is
1837          * no current trace chunk on the parent channel.
1838          */
1839         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor &&
1840                         stream->chan->trace_chunk) {
1841                 ret = consumer_stream_create_output_files(stream, true);
1842                 if (ret) {
1843                         goto error;
1844                 }
1845         }
1846
1847         if (stream->output == LTTNG_EVENT_MMAP) {
1848                 /* get the len of the mmap region */
1849                 unsigned long mmap_len;
1850
1851                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1852                 if (ret != 0) {
1853                         PERROR("kernctl_get_mmap_len");
1854                         goto error_close_fd;
1855                 }
1856                 stream->mmap_len = (size_t) mmap_len;
1857
1858                 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
1859                                 MAP_PRIVATE, stream->wait_fd, 0);
1860                 if (stream->mmap_base == MAP_FAILED) {
1861                         PERROR("Error mmaping");
1862                         ret = -1;
1863                         goto error_close_fd;
1864                 }
1865         }
1866
1867         ret = lttng_kconsumer_set_stream_ops(stream);
1868         if (ret) {
1869                 goto error_close_fd;
1870         }
1871
1872         /* we return 0 to let the library handle the FD internally */
1873         return 0;
1874
1875 error_close_fd:
1876         if (stream->out_fd >= 0) {
1877                 int err;
1878
1879                 err = close(stream->out_fd);
1880                 LTTNG_ASSERT(!err);
1881                 stream->out_fd = -1;
1882         }
1883 error:
1884         return ret;
1885 }
1886
1887 /*
1888  * Check if data is still being extracted from the buffers for a specific
1889  * stream. Consumer data lock MUST be acquired before calling this function
1890  * and the stream lock.
1891  *
1892  * Return 1 if the traced data are still getting read else 0 meaning that the
1893  * data is available for trace viewer reading.
1894  */
1895 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1896 {
1897         int ret;
1898
1899         LTTNG_ASSERT(stream);
1900
1901         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1902                 ret = 0;
1903                 goto end;
1904         }
1905
1906         ret = kernctl_get_next_subbuf(stream->wait_fd);
1907         if (ret == 0) {
1908                 /* There is still data so let's put back this subbuffer. */
1909                 ret = kernctl_put_subbuf(stream->wait_fd);
1910                 LTTNG_ASSERT(ret == 0);
1911                 ret = 1;   /* Data is pending */
1912                 goto end;
1913         }
1914
1915         /* Data is NOT pending and ready to be read. */
1916         ret = 0;
1917
1918 end:
1919         return ret;
1920 }