src/common/kernel-consumer/kernel-consumer.cpp

   1 /*
   2  * Copyright (C) 2011 EfficiOS Inc.
   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 = (const char *) 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.
 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         /* Prevent channel modifications while we perform the snapshot.*/
 157         pthread_mutex_lock(&channel->lock);
 158
 159         rcu_read_lock();
 160
 161         /* Splice is not supported yet for channel snapshot. */
 162         if (channel->output != CONSUMER_CHANNEL_MMAP) {
 163                 ERR("Unsupported output type for channel \"%s\": mmap output is required to record a snapshot",
 164                                 channel->name);
 165                 ret = -1;
 166                 goto end;
 167         }
 168
 169         cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
 170                 unsigned long consumed_pos, produced_pos;
 171
 172                 health_code_update();
 173
 174                 /*
 175                  * Lock stream because we are about to change its state.
 176                  */
 177                 pthread_mutex_lock(&stream->lock);
 178
 179                 LTTNG_ASSERT(channel->trace_chunk);
 180                 if (!lttng_trace_chunk_get(channel->trace_chunk)) {
 181                         /*
 182                          * Can't happen barring an internal error as the channel
 183                          * holds a reference to the trace chunk.
 184                          */
 185                         ERR("Failed to acquire reference to channel's trace chunk");
 186                         ret = -1;
 187                         goto end_unlock;
 188                 }
 189                 LTTNG_ASSERT(!stream->trace_chunk);
 190                 stream->trace_chunk = channel->trace_chunk;
 191
 192                 /*
 193                  * Assign the received relayd ID so we can use it for streaming. The streams
 194                  * are not visible to anyone so this is OK to change it.
 195                  */
 196                 stream->net_seq_idx = relayd_id;
 197                 channel->relayd_id = relayd_id;
 198                 if (relayd_id != (uint64_t) -1ULL) {
 199                         ret = consumer_send_relayd_stream(stream, path);
 200                         if (ret < 0) {
 201                                 ERR("sending stream to relayd");
 202                                 goto end_unlock;
 203                         }
 204                 } else {
 205                         ret = consumer_stream_create_output_files(stream,
 206                                         false);
 207                         if (ret < 0) {
 208                                 goto end_unlock;
 209                         }
 210                         DBG("Kernel consumer snapshot stream (%" PRIu64 ")",
 211                                         stream->key);
 212                 }
 213
 214                 ret = kernctl_buffer_flush_empty(stream->wait_fd);
 215                 if (ret < 0) {
 216                         /*
 217                          * Doing a buffer flush which does not take into
 218                          * account empty packets. This is not perfect
 219                          * for stream intersection, but required as a
 220                          * fall-back when "flush_empty" is not
 221                          * implemented by lttng-modules.
 222                          */
 223                         ret = kernctl_buffer_flush(stream->wait_fd);
 224                         if (ret < 0) {
 225                                 ERR("Failed to flush kernel stream");
 226                                 goto end_unlock;
 227                         }
 228                         goto end_unlock;
 229                 }
 230
 231                 ret = lttng_kconsumer_take_snapshot(stream);
 232                 if (ret < 0) {
 233                         ERR("Taking kernel snapshot");
 234                         goto end_unlock;
 235                 }
 236
 237                 ret = lttng_kconsumer_get_produced_snapshot(stream, &produced_pos);
 238                 if (ret < 0) {
 239                         ERR("Produced kernel snapshot position");
 240                         goto end_unlock;
 241                 }
 242
 243                 ret = lttng_kconsumer_get_consumed_snapshot(stream, &consumed_pos);
 244                 if (ret < 0) {
 245                         ERR("Consumerd kernel snapshot position");
 246                         goto end_unlock;
 247                 }
 248
 249                 consumed_pos = consumer_get_consume_start_pos(consumed_pos,
 250                                 produced_pos, nb_packets_per_stream,
 251                                 stream->max_sb_size);
 252
 253                 while ((long) (consumed_pos - produced_pos) < 0) {
 254                         ssize_t read_len;
 255                         unsigned long len, padded_len;
 256                         const char *subbuf_addr;
 257                         struct lttng_buffer_view subbuf_view;
 258
 259                         health_code_update();
 260                         DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 261
 262                         ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
 263                         if (ret < 0) {
 264                                 if (ret != -EAGAIN) {
 265                                         PERROR("kernctl_get_subbuf snapshot");
 266                                         goto end_unlock;
 267                                 }
 268                                 DBG("Kernel consumer get subbuf failed. Skipping it.");
 269                                 consumed_pos += stream->max_sb_size;
 270                                 stream->chan->lost_packets++;
 271                                 continue;
 272                         }
 273
 274                         ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
 275                         if (ret < 0) {
 276                                 ERR("Snapshot kernctl_get_subbuf_size");
 277                                 goto error_put_subbuf;
 278                         }
 279
 280                         ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
 281                         if (ret < 0) {
 282                                 ERR("Snapshot kernctl_get_padded_subbuf_size");
 283                                 goto error_put_subbuf;
 284                         }
 285
 286                         ret = get_current_subbuf_addr(stream, &subbuf_addr);
 287                         if (ret) {
 288                                 goto error_put_subbuf;
 289                         }
 290
 291                         subbuf_view = lttng_buffer_view_init(
 292                                         subbuf_addr, 0, padded_len);
 293                         read_len = lttng_consumer_on_read_subbuffer_mmap(
 294                                         stream, &subbuf_view,
 295                                         padded_len - len);
 296                         /*
 297                          * We write the padded len in local tracefiles but the data len
 298                          * when using a relay. Display the error but continue processing
 299                          * to try to release the subbuffer.
 300                          */
 301                         if (relayd_id != (uint64_t) -1ULL) {
 302                                 if (read_len != len) {
 303                                         ERR("Error sending to the relay (ret: %zd != len: %lu)",
 304                                                         read_len, len);
 305                                 }
 306                         } else {
 307                                 if (read_len != padded_len) {
 308                                         ERR("Error writing to tracefile (ret: %zd != len: %lu)",
 309                                                         read_len, padded_len);
 310                                 }
 311                         }
 312
 313                         ret = kernctl_put_subbuf(stream->wait_fd);
 314                         if (ret < 0) {
 315                                 ERR("Snapshot kernctl_put_subbuf");
 316                                 goto end_unlock;
 317                         }
 318                         consumed_pos += stream->max_sb_size;
 319                 }
 320
 321                 if (relayd_id == (uint64_t) -1ULL) {
 322                         if (stream->out_fd >= 0) {
 323                                 ret = close(stream->out_fd);
 324                                 if (ret < 0) {
 325                                         PERROR("Kernel consumer snapshot close out_fd");
 326                                         goto end_unlock;
 327                                 }
 328                                 stream->out_fd = -1;
 329                         }
 330                 } else {
 331                         close_relayd_stream(stream);
 332                         stream->net_seq_idx = (uint64_t) -1ULL;
 333                 }
 334                 lttng_trace_chunk_put(stream->trace_chunk);
 335                 stream->trace_chunk = NULL;
 336                 pthread_mutex_unlock(&stream->lock);
 337         }
 338
 339         /* All good! */
 340         ret = 0;
 341         goto end;
 342
 343 error_put_subbuf:
 344         ret = kernctl_put_subbuf(stream->wait_fd);
 345         if (ret < 0) {
 346                 ERR("Snapshot kernctl_put_subbuf error path");
 347         }
 348 end_unlock:
 349         pthread_mutex_unlock(&stream->lock);
 350 end:
 351         rcu_read_unlock();
 352         pthread_mutex_unlock(&channel->lock);
 353         return ret;
 354 }
 355
 356 /*
 357  * Read the whole metadata available for a snapshot.
 358  * RCU read-side lock must be held across this function to ensure existence of
 359  * metadata_channel.
 360  *
 361  * Returns 0 on success, < 0 on error
 362  */
 363 static int lttng_kconsumer_snapshot_metadata(
 364                 struct lttng_consumer_channel *metadata_channel,
 365                 uint64_t key, char *path, uint64_t relayd_id,
 366                 struct lttng_consumer_local_data *ctx)
 367 {
 368         int ret, use_relayd = 0;
 369         ssize_t ret_read;
 370         struct lttng_consumer_stream *metadata_stream;
 371
 372         LTTNG_ASSERT(ctx);
 373
 374         DBG("Kernel consumer snapshot metadata with key %" PRIu64 " at path %s",
 375                         key, path);
 376
 377         rcu_read_lock();
 378
 379         metadata_stream = metadata_channel->metadata_stream;
 380         LTTNG_ASSERT(metadata_stream);
 381
 382         metadata_stream->read_subbuffer_ops.lock(metadata_stream);
 383         LTTNG_ASSERT(metadata_channel->trace_chunk);
 384         LTTNG_ASSERT(metadata_stream->trace_chunk);
 385
 386         /* Flag once that we have a valid relayd for the stream. */
 387         if (relayd_id != (uint64_t) -1ULL) {
 388                 use_relayd = 1;
 389         }
 390
 391         if (use_relayd) {
 392                 ret = consumer_send_relayd_stream(metadata_stream, path);
 393                 if (ret < 0) {
 394                         goto error_snapshot;
 395                 }
 396         } else {
 397                 ret = consumer_stream_create_output_files(metadata_stream,
 398                                 false);
 399                 if (ret < 0) {
 400                         goto error_snapshot;
 401                 }
 402         }
 403
 404         do {
 405                 health_code_update();
 406
 407                 ret_read = lttng_consumer_read_subbuffer(metadata_stream, ctx, true);
 408                 if (ret_read < 0) {
 409                         ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
 410                                         ret_read);
 411                         ret = ret_read;
 412                         goto error_snapshot;
 413                 }
 414         } while (ret_read > 0);
 415
 416         if (use_relayd) {
 417                 close_relayd_stream(metadata_stream);
 418                 metadata_stream->net_seq_idx = (uint64_t) -1ULL;
 419         } else {
 420                 if (metadata_stream->out_fd >= 0) {
 421                         ret = close(metadata_stream->out_fd);
 422                         if (ret < 0) {
 423                                 PERROR("Kernel consumer snapshot metadata close out_fd");
 424                                 /*
 425                                  * Don't go on error here since the snapshot was successful at this
 426                                  * point but somehow the close failed.
 427                                  */
 428                         }
 429                         metadata_stream->out_fd = -1;
 430                         lttng_trace_chunk_put(metadata_stream->trace_chunk);
 431                         metadata_stream->trace_chunk = NULL;
 432                 }
 433         }
 434
 435         ret = 0;
 436 error_snapshot:
 437         metadata_stream->read_subbuffer_ops.unlock(metadata_stream);
 438         consumer_stream_destroy(metadata_stream, NULL);
 439         metadata_channel->metadata_stream = NULL;
 440         rcu_read_unlock();
 441         return ret;
 442 }
 443
 444 /*
 445  * Receive command from session daemon and process it.
 446  *
 447  * Return 1 on success else a negative value or 0.
 448  */
 449 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 450                 int sock, struct pollfd *consumer_sockpoll)
 451 {
 452         int ret_func;
 453         enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 454         struct lttcomm_consumer_msg msg;
 455
 456         health_code_update();
 457
 458         {
 459                 ssize_t ret_recv;
 460
 461                 ret_recv = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 462                 if (ret_recv != sizeof(msg)) {
 463                         if (ret_recv > 0) {
 464                                 lttng_consumer_send_error(ctx,
 465                                                 LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 466                                 ret_recv = -1;
 467                         }
 468                         return ret_recv;
 469                 }
 470         }
 471
 472         health_code_update();
 473
 474         /* Deprecated command */
 475         LTTNG_ASSERT(msg.cmd_type != LTTNG_CONSUMER_STOP);
 476
 477         health_code_update();
 478
 479         /* relayd needs RCU read-side protection */
 480         rcu_read_lock();
 481
 482         switch (msg.cmd_type) {
 483         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 484         {
 485                 uint32_t major = msg.u.relayd_sock.major;
 486                 uint32_t minor = msg.u.relayd_sock.minor;
 487                 enum lttcomm_sock_proto protocol = (enum lttcomm_sock_proto)
 488                                 msg.u.relayd_sock.relayd_socket_protocol;
 489
 490                 /* Session daemon status message are handled in the following call. */
 491                 consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 492                                 msg.u.relayd_sock.type, ctx, sock,
 493                                 consumer_sockpoll, msg.u.relayd_sock.session_id,
 494                                 msg.u.relayd_sock.relayd_session_id, major,
 495                                 minor, protocol);
 496                 goto end_nosignal;
 497         }
 498         case LTTNG_CONSUMER_ADD_CHANNEL:
 499         {
 500                 struct lttng_consumer_channel *new_channel;
 501                 int ret_send_status, ret_add_channel = 0;
 502                 const uint64_t chunk_id = msg.u.channel.chunk_id.value;
 503
 504                 health_code_update();
 505
 506                 /* First send a status message before receiving the fds. */
 507                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 508                 if (ret_send_status < 0) {
 509                         /* Somehow, the session daemon is not responding anymore. */
 510                         goto error_fatal;
 511                 }
 512
 513                 health_code_update();
 514
 515                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 516                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 517                                 msg.u.channel.session_id,
 518                                 msg.u.channel.chunk_id.is_set ?
 519                                                 &chunk_id : NULL,
 520                                 msg.u.channel.pathname,
 521                                 msg.u.channel.name,
 522                                 msg.u.channel.relayd_id, msg.u.channel.output,
 523                                 msg.u.channel.tracefile_size,
 524                                 msg.u.channel.tracefile_count, 0,
 525                                 msg.u.channel.monitor,
 526                                 msg.u.channel.live_timer_interval,
 527                                 msg.u.channel.is_live,
 528                                 NULL, NULL);
 529                 if (new_channel == NULL) {
 530                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 531                         goto end_nosignal;
 532                 }
 533                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 534                 switch (msg.u.channel.output) {
 535                 case LTTNG_EVENT_SPLICE:
 536                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 537                         break;
 538                 case LTTNG_EVENT_MMAP:
 539                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 540                         break;
 541                 default:
 542                         ERR("Channel output unknown %d", msg.u.channel.output);
 543                         goto end_nosignal;
 544                 }
 545
 546                 /* Translate and save channel type. */
 547                 switch (msg.u.channel.type) {
 548                 case CONSUMER_CHANNEL_TYPE_DATA:
 549                 case CONSUMER_CHANNEL_TYPE_METADATA:
 550                         new_channel->type = (consumer_channel_type) msg.u.channel.type;
 551                         break;
 552                 default:
 553                         abort();
 554                         goto end_nosignal;
 555                 };
 556
 557                 health_code_update();
 558
 559                 if (ctx->on_recv_channel != NULL) {
 560                         int ret_recv_channel =
 561                                         ctx->on_recv_channel(new_channel);
 562                         if (ret_recv_channel == 0) {
 563                                 ret_add_channel = consumer_add_channel(
 564                                                 new_channel, ctx);
 565                         } else if (ret_recv_channel < 0) {
 566                                 goto end_nosignal;
 567                         }
 568                 } else {
 569                         ret_add_channel =
 570                                         consumer_add_channel(new_channel, ctx);
 571                 }
 572                 if (msg.u.channel.type == CONSUMER_CHANNEL_TYPE_DATA &&
 573                                 !ret_add_channel) {
 574                         int monitor_start_ret;
 575
 576                         DBG("Consumer starting monitor timer");
 577                         consumer_timer_live_start(new_channel,
 578                                         msg.u.channel.live_timer_interval);
 579                         monitor_start_ret = consumer_timer_monitor_start(
 580                                         new_channel,
 581                                         msg.u.channel.monitor_timer_interval);
 582                         if (monitor_start_ret < 0) {
 583                                 ERR("Starting channel monitoring timer failed");
 584                                 goto end_nosignal;
 585                         }
 586                 }
 587
 588                 health_code_update();
 589
 590                 /* If we received an error in add_channel, we need to report it. */
 591                 if (ret_add_channel < 0) {
 592                         ret_send_status = consumer_send_status_msg(
 593                                         sock, ret_add_channel);
 594                         if (ret_send_status < 0) {
 595                                 goto error_fatal;
 596                         }
 597                         goto end_nosignal;
 598                 }
 599
 600                 goto end_nosignal;
 601         }
 602         case LTTNG_CONSUMER_ADD_STREAM:
 603         {
 604                 int fd;
 605                 struct lttng_pipe *stream_pipe;
 606                 struct lttng_consumer_stream *new_stream;
 607                 struct lttng_consumer_channel *channel;
 608                 int alloc_ret = 0;
 609                 int ret_send_status, ret_poll, ret_get_max_subbuf_size;
 610                 ssize_t ret_pipe_write, ret_recv;
 611
 612                 /*
 613                  * Get stream's channel reference. Needed when adding the stream to the
 614                  * global hash table.
 615                  */
 616                 channel = consumer_find_channel(msg.u.stream.channel_key);
 617                 if (!channel) {
 618                         /*
 619                          * We could not find the channel. Can happen if cpu hotplug
 620                          * happens while tearing down.
 621                          */
 622                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 623                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 624                 }
 625
 626                 health_code_update();
 627
 628                 /* First send a status message before receiving the fds. */
 629                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 630                 if (ret_send_status < 0) {
 631                         /* Somehow, the session daemon is not responding anymore. */
 632                         goto error_add_stream_fatal;
 633                 }
 634
 635                 health_code_update();
 636
 637                 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 638                         /* Channel was not found. */
 639                         goto error_add_stream_nosignal;
 640                 }
 641
 642                 /* Blocking call */
 643                 health_poll_entry();
 644                 ret_poll = lttng_consumer_poll_socket(consumer_sockpoll);
 645                 health_poll_exit();
 646                 if (ret_poll) {
 647                         goto error_add_stream_fatal;
 648                 }
 649
 650                 health_code_update();
 651
 652                 /* Get stream file descriptor from socket */
 653                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 654                 if (ret_recv != sizeof(fd)) {
 655                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 656                         ret_func = ret_recv;
 657                         goto end;
 658                 }
 659
 660                 health_code_update();
 661
 662                 /*
 663                  * Send status code to session daemon only if the recv works. If the
 664                  * above recv() failed, the session daemon is notified through the
 665                  * error socket and the teardown is eventually done.
 666                  */
 667                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 668                 if (ret_send_status < 0) {
 669                         /* Somehow, the session daemon is not responding anymore. */
 670                         goto error_add_stream_nosignal;
 671                 }
 672
 673                 health_code_update();
 674
 675                 pthread_mutex_lock(&channel->lock);
 676                 new_stream = consumer_stream_create(
 677                                 channel,
 678                                 channel->key,
 679                                 fd,
 680                                 channel->name,
 681                                 channel->relayd_id,
 682                                 channel->session_id,
 683                                 channel->trace_chunk,
 684                                 msg.u.stream.cpu,
 685                                 &alloc_ret,
 686                                 channel->type,
 687                                 channel->monitor);
 688                 if (new_stream == NULL) {
 689                         switch (alloc_ret) {
 690                         case -ENOMEM:
 691                         case -EINVAL:
 692                         default:
 693                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 694                                 break;
 695                         }
 696                         pthread_mutex_unlock(&channel->lock);
 697                         goto error_add_stream_nosignal;
 698                 }
 699
 700                 new_stream->wait_fd = fd;
 701                 ret_get_max_subbuf_size = kernctl_get_max_subbuf_size(
 702                                 new_stream->wait_fd, &new_stream->max_sb_size);
 703                 if (ret_get_max_subbuf_size < 0) {
 704                         pthread_mutex_unlock(&channel->lock);
 705                         ERR("Failed to get kernel maximal subbuffer size");
 706                         goto error_add_stream_nosignal;
 707                 }
 708
 709                 consumer_stream_update_channel_attributes(new_stream,
 710                                 channel);
 711
 712                 /*
 713                  * We've just assigned the channel to the stream so increment the
 714                  * refcount right now. We don't need to increment the refcount for
 715                  * streams in no monitor because we handle manually the cleanup of
 716                  * those. It is very important to make sure there is NO prior
 717                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 718                  */
 719                 if (channel->monitor) {
 720                         uatomic_inc(&new_stream->chan->refcount);
 721                 }
 722
 723                 /*
 724                  * The buffer flush is done on the session daemon side for the kernel
 725                  * so no need for the stream "hangup_flush_done" variable to be
 726                  * tracked. This is important for a kernel stream since we don't rely
 727                  * on the flush state of the stream to read data. It's not the case for
 728                  * user space tracing.
 729                  */
 730                 new_stream->hangup_flush_done = 0;
 731
 732                 health_code_update();
 733
 734                 pthread_mutex_lock(&new_stream->lock);
 735                 if (ctx->on_recv_stream) {
 736                         int ret_recv_stream = ctx->on_recv_stream(new_stream);
 737                         if (ret_recv_stream < 0) {
 738                                 pthread_mutex_unlock(&new_stream->lock);
 739                                 pthread_mutex_unlock(&channel->lock);
 740                                 consumer_stream_free(new_stream);
 741                                 goto error_add_stream_nosignal;
 742                         }
 743                 }
 744                 health_code_update();
 745
 746                 if (new_stream->metadata_flag) {
 747                         channel->metadata_stream = new_stream;
 748                 }
 749
 750                 /* Do not monitor this stream. */
 751                 if (!channel->monitor) {
 752                         DBG("Kernel consumer add stream %s in no monitor mode with "
 753                                         "relayd id %" PRIu64, new_stream->name,
 754                                         new_stream->net_seq_idx);
 755                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 756                         pthread_mutex_unlock(&new_stream->lock);
 757                         pthread_mutex_unlock(&channel->lock);
 758                         goto end_add_stream;
 759                 }
 760
 761                 /* Send stream to relayd if the stream has an ID. */
 762                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 763                         int ret_send_relayd_stream;
 764
 765                         ret_send_relayd_stream = consumer_send_relayd_stream(
 766                                         new_stream, new_stream->chan->pathname);
 767                         if (ret_send_relayd_stream < 0) {
 768                                 pthread_mutex_unlock(&new_stream->lock);
 769                                 pthread_mutex_unlock(&channel->lock);
 770                                 consumer_stream_free(new_stream);
 771                                 goto error_add_stream_nosignal;
 772                         }
 773
 774                         /*
 775                          * If adding an extra stream to an already
 776                          * existing channel (e.g. cpu hotplug), we need
 777                          * to send the "streams_sent" command to relayd.
 778                          */
 779                         if (channel->streams_sent_to_relayd) {
 780                                 int ret_send_relayd_streams_sent;
 781
 782                                 ret_send_relayd_streams_sent =
 783                                                 consumer_send_relayd_streams_sent(
 784                                                                 new_stream->net_seq_idx);
 785                                 if (ret_send_relayd_streams_sent < 0) {
 786                                         pthread_mutex_unlock(&new_stream->lock);
 787                                         pthread_mutex_unlock(&channel->lock);
 788                                         goto error_add_stream_nosignal;
 789                                 }
 790                         }
 791                 }
 792                 pthread_mutex_unlock(&new_stream->lock);
 793                 pthread_mutex_unlock(&channel->lock);
 794
 795                 /* Get the right pipe where the stream will be sent. */
 796                 if (new_stream->metadata_flag) {
 797                         consumer_add_metadata_stream(new_stream);
 798                         stream_pipe = ctx->consumer_metadata_pipe;
 799                 } else {
 800                         consumer_add_data_stream(new_stream);
 801                         stream_pipe = ctx->consumer_data_pipe;
 802                 }
 803
 804                 /* Visible to other threads */
 805                 new_stream->globally_visible = 1;
 806
 807                 health_code_update();
 808
 809                 ret_pipe_write = lttng_pipe_write(
 810                                 stream_pipe, &new_stream, sizeof(new_stream));
 811                 if (ret_pipe_write < 0) {
 812                         ERR("Consumer write %s stream to pipe %d",
 813                                         new_stream->metadata_flag ? "metadata" : "data",
 814                                         lttng_pipe_get_writefd(stream_pipe));
 815                         if (new_stream->metadata_flag) {
 816                                 consumer_del_stream_for_metadata(new_stream);
 817                         } else {
 818                                 consumer_del_stream_for_data(new_stream);
 819                         }
 820                         goto error_add_stream_nosignal;
 821                 }
 822
 823                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
 824                                 new_stream->name, fd, new_stream->chan->pathname, new_stream->relayd_stream_id);
 825 end_add_stream:
 826                 break;
 827 error_add_stream_nosignal:
 828                 goto end_nosignal;
 829 error_add_stream_fatal:
 830                 goto error_fatal;
 831         }
 832         case LTTNG_CONSUMER_STREAMS_SENT:
 833         {
 834                 struct lttng_consumer_channel *channel;
 835                 int ret_send_status;
 836
 837                 /*
 838                  * Get stream's channel reference. Needed when adding the stream to the
 839                  * global hash table.
 840                  */
 841                 channel = consumer_find_channel(msg.u.sent_streams.channel_key);
 842                 if (!channel) {
 843                         /*
 844                          * We could not find the channel. Can happen if cpu hotplug
 845                          * happens while tearing down.
 846                          */
 847                         ERR("Unable to find channel key %" PRIu64,
 848                                         msg.u.sent_streams.channel_key);
 849                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 850                 }
 851
 852                 health_code_update();
 853
 854                 /*
 855                  * Send status code to session daemon.
 856                  */
 857                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 858                 if (ret_send_status < 0 ||
 859                                 ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 860                         /* Somehow, the session daemon is not responding anymore. */
 861                         goto error_streams_sent_nosignal;
 862                 }
 863
 864                 health_code_update();
 865
 866                 /*
 867                  * We should not send this message if we don't monitor the
 868                  * streams in this channel.
 869                  */
 870                 if (!channel->monitor) {
 871                         goto end_error_streams_sent;
 872                 }
 873
 874                 health_code_update();
 875                 /* Send stream to relayd if the stream has an ID. */
 876                 if (msg.u.sent_streams.net_seq_idx != (uint64_t) -1ULL) {
 877                         int ret_send_relay_streams;
 878
 879                         ret_send_relay_streams = consumer_send_relayd_streams_sent(
 880                                         msg.u.sent_streams.net_seq_idx);
 881                         if (ret_send_relay_streams < 0) {
 882                                 goto error_streams_sent_nosignal;
 883                         }
 884                         channel->streams_sent_to_relayd = true;
 885                 }
 886 end_error_streams_sent:
 887                 break;
 888 error_streams_sent_nosignal:
 889                 goto end_nosignal;
 890         }
 891         case LTTNG_CONSUMER_UPDATE_STREAM:
 892         {
 893                 rcu_read_unlock();
 894                 return -ENOSYS;
 895         }
 896         case LTTNG_CONSUMER_DESTROY_RELAYD:
 897         {
 898                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 899                 struct consumer_relayd_sock_pair *relayd;
 900                 int ret_send_status;
 901
 902                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 903
 904                 /* Get relayd reference if exists. */
 905                 relayd = consumer_find_relayd(index);
 906                 if (relayd == NULL) {
 907                         DBG("Unable to find relayd %" PRIu64, index);
 908                         ret_code = LTTCOMM_CONSUMERD_RELAYD_FAIL;
 909                 }
 910
 911                 /*
 912                  * Each relayd socket pair has a refcount of stream attached to it
 913                  * which tells if the relayd is still active or not depending on the
 914                  * refcount value.
 915                  *
 916                  * This will set the destroy flag of the relayd object and destroy it
 917                  * if the refcount reaches zero when called.
 918                  *
 919                  * The destroy can happen either here or when a stream fd hangs up.
 920                  */
 921                 if (relayd) {
 922                         consumer_flag_relayd_for_destroy(relayd);
 923                 }
 924
 925                 health_code_update();
 926
 927                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 928                 if (ret_send_status < 0) {
 929                         /* Somehow, the session daemon is not responding anymore. */
 930                         goto error_fatal;
 931                 }
 932
 933                 goto end_nosignal;
 934         }
 935         case LTTNG_CONSUMER_DATA_PENDING:
 936         {
 937                 int32_t ret_data_pending;
 938                 uint64_t id = msg.u.data_pending.session_id;
 939                 ssize_t ret_send;
 940
 941                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 942
 943                 ret_data_pending = consumer_data_pending(id);
 944
 945                 health_code_update();
 946
 947                 /* Send back returned value to session daemon */
 948                 ret_send = lttcomm_send_unix_sock(sock, &ret_data_pending,
 949                                 sizeof(ret_data_pending));
 950                 if (ret_send < 0) {
 951                         PERROR("send data pending ret code");
 952                         goto error_fatal;
 953                 }
 954
 955                 /*
 956                  * No need to send back a status message since the data pending
 957                  * returned value is the response.
 958                  */
 959                 break;
 960         }
 961         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 962         {
 963                 struct lttng_consumer_channel *channel;
 964                 uint64_t key = msg.u.snapshot_channel.key;
 965                 int ret_send_status;
 966
 967                 channel = consumer_find_channel(key);
 968                 if (!channel) {
 969                         ERR("Channel %" PRIu64 " not found", key);
 970                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 971                 } else {
 972                         if (msg.u.snapshot_channel.metadata == 1) {
 973                                 int ret_snapshot;
 974
 975                                 ret_snapshot = lttng_kconsumer_snapshot_metadata(
 976                                                 channel, key,
 977                                                 msg.u.snapshot_channel.pathname,
 978                                                 msg.u.snapshot_channel.relayd_id,
 979                                                 ctx);
 980                                 if (ret_snapshot < 0) {
 981                                         ERR("Snapshot metadata failed");
 982                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 983                                 }
 984                         } else {
 985                                 int ret_snapshot;
 986
 987                                 ret_snapshot = lttng_kconsumer_snapshot_channel(
 988                                                 channel, key,
 989                                                 msg.u.snapshot_channel.pathname,
 990                                                 msg.u.snapshot_channel.relayd_id,
 991                                                 msg.u.snapshot_channel
 992                                                                 .nb_packets_per_stream,
 993                                                 ctx);
 994                                 if (ret_snapshot < 0) {
 995                                         ERR("Snapshot channel failed");
 996                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 997                                 }
 998                         }
 999                 }
1000                 health_code_update();
1001
1002                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1003                 if (ret_send_status < 0) {
1004                         /* Somehow, the session daemon is not responding anymore. */
1005                         goto end_nosignal;
1006                 }
1007                 break;
1008         }
1009         case LTTNG_CONSUMER_DESTROY_CHANNEL:
1010         {
1011                 uint64_t key = msg.u.destroy_channel.key;
1012                 struct lttng_consumer_channel *channel;
1013                 int ret_send_status;
1014
1015                 channel = consumer_find_channel(key);
1016                 if (!channel) {
1017                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
1018                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1019                 }
1020
1021                 health_code_update();
1022
1023                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1024                 if (ret_send_status < 0) {
1025                         /* Somehow, the session daemon is not responding anymore. */
1026                         goto end_destroy_channel;
1027                 }
1028
1029                 health_code_update();
1030
1031                 /* Stop right now if no channel was found. */
1032                 if (!channel) {
1033                         goto end_destroy_channel;
1034                 }
1035
1036                 /*
1037                  * This command should ONLY be issued for channel with streams set in
1038                  * no monitor mode.
1039                  */
1040                 LTTNG_ASSERT(!channel->monitor);
1041
1042                 /*
1043                  * The refcount should ALWAYS be 0 in the case of a channel in no
1044                  * monitor mode.
1045                  */
1046                 LTTNG_ASSERT(!uatomic_sub_return(&channel->refcount, 1));
1047
1048                 consumer_del_channel(channel);
1049 end_destroy_channel:
1050                 goto end_nosignal;
1051         }
1052         case LTTNG_CONSUMER_DISCARDED_EVENTS:
1053         {
1054                 ssize_t ret;
1055                 uint64_t count;
1056                 struct lttng_consumer_channel *channel;
1057                 uint64_t id = msg.u.discarded_events.session_id;
1058                 uint64_t key = msg.u.discarded_events.channel_key;
1059
1060                 DBG("Kernel consumer discarded events command for session id %"
1061                                 PRIu64 ", channel key %" PRIu64, id, key);
1062
1063                 channel = consumer_find_channel(key);
1064                 if (!channel) {
1065                         ERR("Kernel consumer discarded events channel %"
1066                                         PRIu64 " not found", key);
1067                         count = 0;
1068                 } else {
1069                         count = channel->discarded_events;
1070                 }
1071
1072                 health_code_update();
1073
1074                 /* Send back returned value to session daemon */
1075                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1076                 if (ret < 0) {
1077                         PERROR("send discarded events");
1078                         goto error_fatal;
1079                 }
1080
1081                 break;
1082         }
1083         case LTTNG_CONSUMER_LOST_PACKETS:
1084         {
1085                 ssize_t ret;
1086                 uint64_t count;
1087                 struct lttng_consumer_channel *channel;
1088                 uint64_t id = msg.u.lost_packets.session_id;
1089                 uint64_t key = msg.u.lost_packets.channel_key;
1090
1091                 DBG("Kernel consumer lost packets command for session id %"
1092                                 PRIu64 ", channel key %" PRIu64, id, key);
1093
1094                 channel = consumer_find_channel(key);
1095                 if (!channel) {
1096                         ERR("Kernel consumer lost packets channel %"
1097                                         PRIu64 " not found", key);
1098                         count = 0;
1099                 } else {
1100                         count = channel->lost_packets;
1101                 }
1102
1103                 health_code_update();
1104
1105                 /* Send back returned value to session daemon */
1106                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1107                 if (ret < 0) {
1108                         PERROR("send lost packets");
1109                         goto error_fatal;
1110                 }
1111
1112                 break;
1113         }
1114         case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
1115         {
1116                 int channel_monitor_pipe;
1117                 int ret_send_status, ret_set_channel_monitor_pipe;
1118                 ssize_t ret_recv;
1119
1120                 ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1121                 /* Successfully received the command's type. */
1122                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1123                 if (ret_send_status < 0) {
1124                         goto error_fatal;
1125                 }
1126
1127                 ret_recv = lttcomm_recv_fds_unix_sock(
1128                                 sock, &channel_monitor_pipe, 1);
1129                 if (ret_recv != sizeof(channel_monitor_pipe)) {
1130                         ERR("Failed to receive channel monitor pipe");
1131                         goto error_fatal;
1132                 }
1133
1134                 DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
1135                 ret_set_channel_monitor_pipe =
1136                                 consumer_timer_thread_set_channel_monitor_pipe(
1137                                                 channel_monitor_pipe);
1138                 if (!ret_set_channel_monitor_pipe) {
1139                         int flags;
1140                         int ret_fcntl;
1141
1142                         ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1143                         /* Set the pipe as non-blocking. */
1144                         ret_fcntl = fcntl(channel_monitor_pipe, F_GETFL, 0);
1145                         if (ret_fcntl == -1) {
1146                                 PERROR("fcntl get flags of the channel monitoring pipe");
1147                                 goto error_fatal;
1148                         }
1149                         flags = ret_fcntl;
1150
1151                         ret_fcntl = fcntl(channel_monitor_pipe, F_SETFL,
1152                                         flags | O_NONBLOCK);
1153                         if (ret_fcntl == -1) {
1154                                 PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
1155                                 goto error_fatal;
1156                         }
1157                         DBG("Channel monitor pipe set as non-blocking");
1158                 } else {
1159                         ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
1160                 }
1161                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1162                 if (ret_send_status < 0) {
1163                         goto error_fatal;
1164                 }
1165                 break;
1166         }
1167         case LTTNG_CONSUMER_ROTATE_CHANNEL:
1168         {
1169                 struct lttng_consumer_channel *channel;
1170                 uint64_t key = msg.u.rotate_channel.key;
1171                 int ret_send_status;
1172
1173                 DBG("Consumer rotate channel %" PRIu64, key);
1174
1175                 channel = consumer_find_channel(key);
1176                 if (!channel) {
1177                         ERR("Channel %" PRIu64 " not found", key);
1178                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1179                 } else {
1180                         /*
1181                          * Sample the rotate position of all the streams in this channel.
1182                          */
1183                         int ret_rotate_channel;
1184
1185                         ret_rotate_channel = lttng_consumer_rotate_channel(
1186                                         channel, key,
1187                                         msg.u.rotate_channel.relayd_id,
1188                                         msg.u.rotate_channel.metadata, ctx);
1189                         if (ret_rotate_channel < 0) {
1190                                 ERR("Rotate channel failed");
1191                                 ret_code = LTTCOMM_CONSUMERD_ROTATION_FAIL;
1192                         }
1193
1194                         health_code_update();
1195                 }
1196
1197                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1198                 if (ret_send_status < 0) {
1199                         /* Somehow, the session daemon is not responding anymore. */
1200                         goto error_rotate_channel;
1201                 }
1202                 if (channel) {
1203                         /* Rotate the streams that are ready right now. */
1204                         int ret_rotate;
1205
1206                         ret_rotate = lttng_consumer_rotate_ready_streams(
1207                                         channel, key, ctx);
1208                         if (ret_rotate < 0) {
1209                                 ERR("Rotate ready streams failed");
1210                         }
1211                 }
1212                 break;
1213 error_rotate_channel:
1214                 goto end_nosignal;
1215         }
1216         case LTTNG_CONSUMER_CLEAR_CHANNEL:
1217         {
1218                 struct lttng_consumer_channel *channel;
1219                 uint64_t key = msg.u.clear_channel.key;
1220                 int ret_send_status;
1221
1222                 channel = consumer_find_channel(key);
1223                 if (!channel) {
1224                         DBG("Channel %" PRIu64 " not found", key);
1225                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1226                 } else {
1227                         int ret_clear_channel;
1228
1229                         ret_clear_channel =
1230                                         lttng_consumer_clear_channel(channel);
1231                         if (ret_clear_channel) {
1232                                 ERR("Clear channel failed");
1233                                 ret_code = (lttcomm_return_code) ret_clear_channel;
1234                         }
1235
1236                         health_code_update();
1237                 }
1238
1239                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1240                 if (ret_send_status < 0) {
1241                         /* Somehow, the session daemon is not responding anymore. */
1242                         goto end_nosignal;
1243                 }
1244
1245                 break;
1246         }
1247         case LTTNG_CONSUMER_INIT:
1248         {
1249                 int ret_send_status;
1250
1251                 ret_code = lttng_consumer_init_command(ctx,
1252                                 msg.u.init.sessiond_uuid);
1253                 health_code_update();
1254                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1255                 if (ret_send_status < 0) {
1256                         /* Somehow, the session daemon is not responding anymore. */
1257                         goto end_nosignal;
1258                 }
1259                 break;
1260         }
1261         case LTTNG_CONSUMER_CREATE_TRACE_CHUNK:
1262         {
1263                 const struct lttng_credentials credentials = {
1264                         .uid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.uid),
1265                         .gid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.gid),
1266                 };
1267                 const bool is_local_trace =
1268                                 !msg.u.create_trace_chunk.relayd_id.is_set;
1269                 const uint64_t relayd_id =
1270                                 msg.u.create_trace_chunk.relayd_id.value;
1271                 const char *chunk_override_name =
1272                                 *msg.u.create_trace_chunk.override_name ?
1273                                         msg.u.create_trace_chunk.override_name :
1274                                         NULL;
1275                 struct lttng_directory_handle *chunk_directory_handle = NULL;
1276
1277                 /*
1278                  * The session daemon will only provide a chunk directory file
1279                  * descriptor for local traces.
1280                  */
1281                 if (is_local_trace) {
1282                         int chunk_dirfd;
1283                         int ret_send_status;
1284                         ssize_t ret_recv;
1285
1286                         /* Acnowledge the reception of the command. */
1287                         ret_send_status = consumer_send_status_msg(
1288                                         sock, LTTCOMM_CONSUMERD_SUCCESS);
1289                         if (ret_send_status < 0) {
1290                                 /* Somehow, the session daemon is not responding anymore. */
1291                                 goto end_nosignal;
1292                         }
1293
1294                         ret_recv = lttcomm_recv_fds_unix_sock(
1295                                         sock, &chunk_dirfd, 1);
1296                         if (ret_recv != sizeof(chunk_dirfd)) {
1297                                 ERR("Failed to receive trace chunk directory file descriptor");
1298                                 goto error_fatal;
1299                         }
1300
1301                         DBG("Received trace chunk directory fd (%d)",
1302                                         chunk_dirfd);
1303                         chunk_directory_handle = lttng_directory_handle_create_from_dirfd(
1304                                         chunk_dirfd);
1305                         if (!chunk_directory_handle) {
1306                                 ERR("Failed to initialize chunk directory handle from directory file descriptor");
1307                                 if (close(chunk_dirfd)) {
1308                                         PERROR("Failed to close chunk directory file descriptor");
1309                                 }
1310                                 goto error_fatal;
1311                         }
1312                 }
1313
1314                 ret_code = lttng_consumer_create_trace_chunk(
1315                                 !is_local_trace ? &relayd_id : NULL,
1316                                 msg.u.create_trace_chunk.session_id,
1317                                 msg.u.create_trace_chunk.chunk_id,
1318                                 (time_t) msg.u.create_trace_chunk
1319                                                 .creation_timestamp,
1320                                 chunk_override_name,
1321                                 msg.u.create_trace_chunk.credentials.is_set ?
1322                                                 &credentials :
1323                                                 NULL,
1324                                 chunk_directory_handle);
1325                 lttng_directory_handle_put(chunk_directory_handle);
1326                 goto end_msg_sessiond;
1327         }
1328         case LTTNG_CONSUMER_CLOSE_TRACE_CHUNK:
1329         {
1330                 enum lttng_trace_chunk_command_type close_command =
1331                                 (lttng_trace_chunk_command_type) msg.u.close_trace_chunk.close_command.value;
1332                 const uint64_t relayd_id =
1333                                 msg.u.close_trace_chunk.relayd_id.value;
1334                 struct lttcomm_consumer_close_trace_chunk_reply reply;
1335                 char path[LTTNG_PATH_MAX];
1336                 ssize_t ret_send;
1337
1338                 ret_code = lttng_consumer_close_trace_chunk(
1339                                 msg.u.close_trace_chunk.relayd_id.is_set ?
1340                                                 &relayd_id :
1341                                                 NULL,
1342                                 msg.u.close_trace_chunk.session_id,
1343                                 msg.u.close_trace_chunk.chunk_id,
1344                                 (time_t) msg.u.close_trace_chunk.close_timestamp,
1345                                 msg.u.close_trace_chunk.close_command.is_set ?
1346                                                 &close_command :
1347                                                 NULL, path);
1348                 reply.ret_code = ret_code;
1349                 reply.path_length = strlen(path) + 1;
1350                 ret_send = lttcomm_send_unix_sock(sock, &reply, sizeof(reply));
1351                 if (ret_send != sizeof(reply)) {
1352                         goto error_fatal;
1353                 }
1354                 ret_send = lttcomm_send_unix_sock(
1355                                 sock, path, reply.path_length);
1356                 if (ret_send != reply.path_length) {
1357                         goto error_fatal;
1358                 }
1359                 goto end_nosignal;
1360         }
1361         case LTTNG_CONSUMER_TRACE_CHUNK_EXISTS:
1362         {
1363                 const uint64_t relayd_id =
1364                                 msg.u.trace_chunk_exists.relayd_id.value;
1365
1366                 ret_code = lttng_consumer_trace_chunk_exists(
1367                                 msg.u.trace_chunk_exists.relayd_id.is_set ?
1368                                                 &relayd_id : NULL,
1369                                 msg.u.trace_chunk_exists.session_id,
1370                                 msg.u.trace_chunk_exists.chunk_id);
1371                 goto end_msg_sessiond;
1372         }
1373         case LTTNG_CONSUMER_OPEN_CHANNEL_PACKETS:
1374         {
1375                 const uint64_t key = msg.u.open_channel_packets.key;
1376                 struct lttng_consumer_channel *channel =
1377                                 consumer_find_channel(key);
1378
1379                 if (channel) {
1380                         pthread_mutex_lock(&channel->lock);
1381                         ret_code = lttng_consumer_open_channel_packets(channel);
1382                         pthread_mutex_unlock(&channel->lock);
1383                 } else {
1384                         WARN("Channel %" PRIu64 " not found", key);
1385                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1386                 }
1387
1388                 health_code_update();
1389                 goto end_msg_sessiond;
1390         }
1391         default:
1392                 goto end_nosignal;
1393         }
1394
1395 end_nosignal:
1396         /*
1397          * Return 1 to indicate success since the 0 value can be a socket
1398          * shutdown during the recv() or send() call.
1399          */
1400         ret_func = 1;
1401         goto end;
1402 error_fatal:
1403         /* This will issue a consumer stop. */
1404         ret_func = -1;
1405         goto end;
1406 end_msg_sessiond:
1407         /*
1408          * The returned value here is not useful since either way we'll return 1 to
1409          * the caller because the session daemon socket management is done
1410          * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1411          */
1412         {
1413                 int ret_send_status;
1414
1415                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1416                 if (ret_send_status < 0) {
1417                         goto error_fatal;
1418                 }
1419         }
1420
1421         ret_func = 1;
1422
1423 end:
1424         health_code_update();
1425         rcu_read_unlock();
1426         return ret_func;
1427 }
1428
1429 /*
1430  * Sync metadata meaning request them to the session daemon and snapshot to the
1431  * metadata thread can consumer them.
1432  *
1433  * Metadata stream lock MUST be acquired.
1434  */
1435 enum sync_metadata_status lttng_kconsumer_sync_metadata(
1436                 struct lttng_consumer_stream *metadata)
1437 {
1438         int ret;
1439         enum sync_metadata_status status;
1440
1441         LTTNG_ASSERT(metadata);
1442
1443         ret = kernctl_buffer_flush(metadata->wait_fd);
1444         if (ret < 0) {
1445                 ERR("Failed to flush kernel stream");
1446                 status = SYNC_METADATA_STATUS_ERROR;
1447                 goto end;
1448         }
1449
1450         ret = kernctl_snapshot(metadata->wait_fd);
1451         if (ret < 0) {
1452                 if (errno == EAGAIN) {
1453                         /* No new metadata, exit. */
1454                         DBG("Sync metadata, no new kernel metadata");
1455                         status = SYNC_METADATA_STATUS_NO_DATA;
1456                 } else {
1457                         ERR("Sync metadata, taking kernel snapshot failed.");
1458                         status = SYNC_METADATA_STATUS_ERROR;
1459                 }
1460         } else {
1461                 status = SYNC_METADATA_STATUS_NEW_DATA;
1462         }
1463
1464 end:
1465         return status;
1466 }
1467
1468 static
1469 int extract_common_subbuffer_info(struct lttng_consumer_stream *stream,
1470                 struct stream_subbuffer *subbuf)
1471 {
1472         int ret;
1473
1474         ret = kernctl_get_subbuf_size(
1475                         stream->wait_fd, &subbuf->info.data.subbuf_size);
1476         if (ret) {
1477                 goto end;
1478         }
1479
1480         ret = kernctl_get_padded_subbuf_size(
1481                         stream->wait_fd, &subbuf->info.data.padded_subbuf_size);
1482         if (ret) {
1483                 goto end;
1484         }
1485
1486 end:
1487         return ret;
1488 }
1489
1490 static
1491 int extract_metadata_subbuffer_info(struct lttng_consumer_stream *stream,
1492                 struct stream_subbuffer *subbuf)
1493 {
1494         int ret;
1495
1496         ret = extract_common_subbuffer_info(stream, subbuf);
1497         if (ret) {
1498                 goto end;
1499         }
1500
1501         ret = kernctl_get_metadata_version(
1502                         stream->wait_fd, &subbuf->info.metadata.version);
1503         if (ret) {
1504                 goto end;
1505         }
1506
1507 end:
1508         return ret;
1509 }
1510
1511 static
1512 int extract_data_subbuffer_info(struct lttng_consumer_stream *stream,
1513                 struct stream_subbuffer *subbuf)
1514 {
1515         int ret;
1516
1517         ret = extract_common_subbuffer_info(stream, subbuf);
1518         if (ret) {
1519                 goto end;
1520         }
1521
1522         ret = kernctl_get_packet_size(
1523                         stream->wait_fd, &subbuf->info.data.packet_size);
1524         if (ret < 0) {
1525                 PERROR("Failed to get sub-buffer packet size");
1526                 goto end;
1527         }
1528
1529         ret = kernctl_get_content_size(
1530                         stream->wait_fd, &subbuf->info.data.content_size);
1531         if (ret < 0) {
1532                 PERROR("Failed to get sub-buffer content size");
1533                 goto end;
1534         }
1535
1536         ret = kernctl_get_timestamp_begin(
1537                         stream->wait_fd, &subbuf->info.data.timestamp_begin);
1538         if (ret < 0) {
1539                 PERROR("Failed to get sub-buffer begin timestamp");
1540                 goto end;
1541         }
1542
1543         ret = kernctl_get_timestamp_end(
1544                         stream->wait_fd, &subbuf->info.data.timestamp_end);
1545         if (ret < 0) {
1546                 PERROR("Failed to get sub-buffer end timestamp");
1547                 goto end;
1548         }
1549
1550         ret = kernctl_get_events_discarded(
1551                         stream->wait_fd, &subbuf->info.data.events_discarded);
1552         if (ret) {
1553                 PERROR("Failed to get sub-buffer events discarded count");
1554                 goto end;
1555         }
1556
1557         ret = kernctl_get_sequence_number(stream->wait_fd,
1558                         &subbuf->info.data.sequence_number.value);
1559         if (ret) {
1560                 /* May not be supported by older LTTng-modules. */
1561                 if (ret != -ENOTTY) {
1562                         PERROR("Failed to get sub-buffer sequence number");
1563                         goto end;
1564                 }
1565         } else {
1566                 subbuf->info.data.sequence_number.is_set = true;
1567         }
1568
1569         ret = kernctl_get_stream_id(
1570                         stream->wait_fd, &subbuf->info.data.stream_id);
1571         if (ret < 0) {
1572                 PERROR("Failed to get stream id");
1573                 goto end;
1574         }
1575
1576         ret = kernctl_get_instance_id(stream->wait_fd,
1577                         &subbuf->info.data.stream_instance_id.value);
1578         if (ret) {
1579                 /* May not be supported by older LTTng-modules. */
1580                 if (ret != -ENOTTY) {
1581                         PERROR("Failed to get stream instance id");
1582                         goto end;
1583                 }
1584         } else {
1585                 subbuf->info.data.stream_instance_id.is_set = true;
1586         }
1587 end:
1588         return ret;
1589 }
1590
1591 static
1592 enum get_next_subbuffer_status get_subbuffer_common(
1593                 struct lttng_consumer_stream *stream,
1594                 struct stream_subbuffer *subbuffer)
1595 {
1596         int ret;
1597         enum get_next_subbuffer_status status;
1598
1599         ret = kernctl_get_next_subbuf(stream->wait_fd);
1600         switch (ret) {
1601         case 0:
1602                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1603                 break;
1604         case -ENODATA:
1605                 case -EAGAIN:
1606                 /*
1607                  * The caller only expects -ENODATA when there is no data to
1608                  * read, but the kernel tracer returns -EAGAIN when there is
1609                  * currently no data for a non-finalized stream, and -ENODATA
1610                  * when there is no data for a finalized stream. Those can be
1611                  * combined into a -ENODATA return value.
1612                  */
1613                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1614                 goto end;
1615         default:
1616                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1617                 goto end;
1618         }
1619
1620         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1621                 stream, subbuffer);
1622         if (ret) {
1623                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1624         }
1625 end:
1626         return status;
1627 }
1628
1629 static
1630 enum get_next_subbuffer_status get_next_subbuffer_splice(
1631                 struct lttng_consumer_stream *stream,
1632                 struct stream_subbuffer *subbuffer)
1633 {
1634         const enum get_next_subbuffer_status status =
1635                         get_subbuffer_common(stream, subbuffer);
1636
1637         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1638                 goto end;
1639         }
1640
1641         subbuffer->buffer.fd = stream->wait_fd;
1642 end:
1643         return status;
1644 }
1645
1646 static
1647 enum get_next_subbuffer_status get_next_subbuffer_mmap(
1648                 struct lttng_consumer_stream *stream,
1649                 struct stream_subbuffer *subbuffer)
1650 {
1651         int ret;
1652         enum get_next_subbuffer_status status;
1653         const char *addr;
1654
1655         status = get_subbuffer_common(stream, subbuffer);
1656         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1657                 goto end;
1658         }
1659
1660         ret = get_current_subbuf_addr(stream, &addr);
1661         if (ret) {
1662                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1663                 goto end;
1664         }
1665
1666         subbuffer->buffer.buffer = lttng_buffer_view_init(
1667                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1668 end:
1669         return status;
1670 }
1671
1672 static
1673 enum get_next_subbuffer_status get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
1674                 struct stream_subbuffer *subbuffer)
1675 {
1676         int ret;
1677         const char *addr;
1678         bool coherent;
1679         enum get_next_subbuffer_status status;
1680
1681         ret = kernctl_get_next_subbuf_metadata_check(stream->wait_fd,
1682                         &coherent);
1683         if (ret) {
1684                 goto end;
1685         }
1686
1687         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1688                         stream, subbuffer);
1689         if (ret) {
1690                 goto end;
1691         }
1692
1693         LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
1694
1695         ret = get_current_subbuf_addr(stream, &addr);
1696         if (ret) {
1697                 goto end;
1698         }
1699
1700         subbuffer->buffer.buffer = lttng_buffer_view_init(
1701                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1702         DBG("Got metadata packet with padded_subbuf_size = %lu, coherent = %s",
1703                         subbuffer->info.metadata.padded_subbuf_size,
1704                         coherent ? "true" : "false");
1705 end:
1706         /*
1707          * The caller only expects -ENODATA when there is no data to read, but
1708          * the kernel tracer returns -EAGAIN when there is currently no data
1709          * for a non-finalized stream, and -ENODATA when there is no data for a
1710          * finalized stream. Those can be combined into a -ENODATA return value.
1711          */
1712         switch (ret) {
1713         case 0:
1714                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1715                 break;
1716         case -ENODATA:
1717         case -EAGAIN:
1718                 /*
1719                  * The caller only expects -ENODATA when there is no data to
1720                  * read, but the kernel tracer returns -EAGAIN when there is
1721                  * currently no data for a non-finalized stream, and -ENODATA
1722                  * when there is no data for a finalized stream. Those can be
1723                  * combined into a -ENODATA return value.
1724                  */
1725                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1726                 break;
1727         default:
1728                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1729                 break;
1730         }
1731
1732         return status;
1733 }
1734
1735 static
1736 int put_next_subbuffer(struct lttng_consumer_stream *stream,
1737                 struct stream_subbuffer *subbuffer)
1738 {
1739         const int ret = kernctl_put_next_subbuf(stream->wait_fd);
1740
1741         if (ret) {
1742                 if (ret == -EFAULT) {
1743                         PERROR("Error in unreserving sub buffer");
1744                 } else if (ret == -EIO) {
1745                         /* Should never happen with newer LTTng versions */
1746                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted");
1747                 }
1748         }
1749
1750         return ret;
1751 }
1752
1753 static
1754 bool is_get_next_check_metadata_available(int tracer_fd)
1755 {
1756         const int ret = kernctl_get_next_subbuf_metadata_check(tracer_fd, NULL);
1757         const bool available = ret != -ENOTTY;
1758
1759         if (ret == 0) {
1760                 /* get succeeded, make sure to put the subbuffer. */
1761                 kernctl_put_subbuf(tracer_fd);
1762         }
1763
1764         return available;
1765 }
1766
1767 static
1768 int signal_metadata(struct lttng_consumer_stream *stream,
1769                 struct lttng_consumer_local_data *ctx)
1770 {
1771         ASSERT_LOCKED(stream->metadata_rdv_lock);
1772         return pthread_cond_broadcast(&stream->metadata_rdv) ? -errno : 0;
1773 }
1774
1775 static
1776 int lttng_kconsumer_set_stream_ops(
1777                 struct lttng_consumer_stream *stream)
1778 {
1779         int ret = 0;
1780
1781         if (stream->metadata_flag && stream->chan->is_live) {
1782                 DBG("Attempting to enable metadata bucketization for live consumers");
1783                 if (is_get_next_check_metadata_available(stream->wait_fd)) {
1784                         DBG("Kernel tracer supports get_next_subbuffer_metadata_check, metadata will be accumulated until a coherent state is reached");
1785                         stream->read_subbuffer_ops.get_next_subbuffer =
1786                                         get_next_subbuffer_metadata_check;
1787                         ret = consumer_stream_enable_metadata_bucketization(
1788                                         stream);
1789                         if (ret) {
1790                                 goto end;
1791                         }
1792                 } else {
1793                         /*
1794                          * The kernel tracer version is too old to indicate
1795                          * when the metadata stream has reached a "coherent"
1796                          * (parseable) point.
1797                          *
1798                          * This means that a live viewer may see an incoherent
1799                          * sequence of metadata and fail to parse it.
1800                          */
1801                         WARN("Kernel tracer does not support get_next_subbuffer_metadata_check which may cause live clients to fail to parse the metadata stream");
1802                         metadata_bucket_destroy(stream->metadata_bucket);
1803                         stream->metadata_bucket = NULL;
1804                 }
1805
1806                 stream->read_subbuffer_ops.on_sleep = signal_metadata;
1807         }
1808
1809         if (!stream->read_subbuffer_ops.get_next_subbuffer) {
1810                 if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
1811                         stream->read_subbuffer_ops.get_next_subbuffer =
1812                                         get_next_subbuffer_mmap;
1813                 } else {
1814                         stream->read_subbuffer_ops.get_next_subbuffer =
1815                                         get_next_subbuffer_splice;
1816                 }
1817         }
1818
1819         if (stream->metadata_flag) {
1820                 stream->read_subbuffer_ops.extract_subbuffer_info =
1821                                 extract_metadata_subbuffer_info;
1822         } else {
1823                 stream->read_subbuffer_ops.extract_subbuffer_info =
1824                                 extract_data_subbuffer_info;
1825                 if (stream->chan->is_live) {
1826                         stream->read_subbuffer_ops.send_live_beacon =
1827                                         consumer_flush_kernel_index;
1828                 }
1829         }
1830
1831         stream->read_subbuffer_ops.put_next_subbuffer = put_next_subbuffer;
1832 end:
1833         return ret;
1834 }
1835
1836 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1837 {
1838         int ret;
1839
1840         LTTNG_ASSERT(stream);
1841
1842         /*
1843          * Don't create anything if this is set for streaming or if there is
1844          * no current trace chunk on the parent channel.
1845          */
1846         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor &&
1847                         stream->chan->trace_chunk) {
1848                 ret = consumer_stream_create_output_files(stream, true);
1849                 if (ret) {
1850                         goto error;
1851                 }
1852         }
1853
1854         if (stream->output == LTTNG_EVENT_MMAP) {
1855                 /* get the len of the mmap region */
1856                 unsigned long mmap_len;
1857
1858                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1859                 if (ret != 0) {
1860                         PERROR("kernctl_get_mmap_len");
1861                         goto error_close_fd;
1862                 }
1863                 stream->mmap_len = (size_t) mmap_len;
1864
1865                 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
1866                                 MAP_PRIVATE, stream->wait_fd, 0);
1867                 if (stream->mmap_base == MAP_FAILED) {
1868                         PERROR("Error mmaping");
1869                         ret = -1;
1870                         goto error_close_fd;
1871                 }
1872         }
1873
1874         ret = lttng_kconsumer_set_stream_ops(stream);
1875         if (ret) {
1876                 goto error_close_fd;
1877         }
1878
1879         /* we return 0 to let the library handle the FD internally */
1880         return 0;
1881
1882 error_close_fd:
1883         if (stream->out_fd >= 0) {
1884                 int err;
1885
1886                 err = close(stream->out_fd);
1887                 LTTNG_ASSERT(!err);
1888                 stream->out_fd = -1;
1889         }
1890 error:
1891         return ret;
1892 }
1893
1894 /*
1895  * Check if data is still being extracted from the buffers for a specific
1896  * stream. Consumer data lock MUST be acquired before calling this function
1897  * and the stream lock.
1898  *
1899  * Return 1 if the traced data are still getting read else 0 meaning that the
1900  * data is available for trace viewer reading.
1901  */
1902 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1903 {
1904         int ret;
1905
1906         LTTNG_ASSERT(stream);
1907
1908         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1909                 ret = 0;
1910                 goto end;
1911         }
1912
1913         ret = kernctl_get_next_subbuf(stream->wait_fd);
1914         if (ret == 0) {
1915                 /* There is still data so let's put back this subbuffer. */
1916                 ret = kernctl_put_subbuf(stream->wait_fd);
1917                 LTTNG_ASSERT(ret == 0);
1918                 ret = 1;   /* Data is pending */
1919                 goto end;
1920         }
1921
1922         /* Data is NOT pending and ready to be read. */
1923         ret = 0;
1924
1925 end:
1926         return ret;
1927 }