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 "kernel-consumer.hpp"
  12
  13 #include <common/buffer-view.hpp>
  14 #include <common/common.hpp>
  15 #include <common/compat/endian.hpp>
  16 #include <common/compat/fcntl.hpp>
  17 #include <common/consumer/consumer-stream.hpp>
  18 #include <common/consumer/consumer-timer.hpp>
  19 #include <common/consumer/consumer.hpp>
  20 #include <common/consumer/metadata-bucket.hpp>
  21 #include <common/index/index.hpp>
  22 #include <common/kernel-ctl/kernel-ctl.hpp>
  23 #include <common/optional.hpp>
  24 #include <common/pipe.hpp>
  25 #include <common/relayd/relayd.hpp>
  26 #include <common/sessiond-comm/relayd.hpp>
  27 #include <common/sessiond-comm/sessiond-comm.hpp>
  28 #include <common/utils.hpp>
  29
  30 #include <bin/lttng-consumerd/health-consumerd.hpp>
  31 #include <inttypes.h>
  32 #include <poll.h>
  33 #include <pthread.h>
  34 #include <stdint.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <sys/mman.h>
  38 #include <sys/socket.h>
  39 #include <sys/stat.h>
  40 #include <sys/types.h>
  41 #include <unistd.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(struct lttng_consumer_stream *stream)
  74 {
  75         LTTNG_ASSERT(stream);
  76
  77         return kernctl_snapshot_sample_positions(stream->wait_fd);
  78 }
  79
  80 /*
  81  * Get the produced position
  82  *
  83  * Returns 0 on success, < 0 on error
  84  */
  85 int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream, unsigned long *pos)
  86 {
  87         int ret;
  88         int infd = stream->wait_fd;
  89
  90         ret = kernctl_snapshot_get_produced(infd, pos);
  91         if (ret != 0) {
  92                 PERROR("kernctl_snapshot_get_produced");
  93         }
  94
  95         return ret;
  96 }
  97
  98 /*
  99  * Get the consumerd position
 100  *
 101  * Returns 0 on success, < 0 on error
 102  */
 103 int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream *stream, unsigned long *pos)
 104 {
 105         int ret;
 106         int infd = stream->wait_fd;
 107
 108         ret = kernctl_snapshot_get_consumed(infd, pos);
 109         if (ret != 0) {
 110                 PERROR("kernctl_snapshot_get_consumed");
 111         }
 112
 113         return ret;
 114 }
 115
 116 static int get_current_subbuf_addr(struct lttng_consumer_stream *stream, const char **addr)
 117 {
 118         int ret;
 119         unsigned long mmap_offset;
 120         const char *mmap_base = (const char *) stream->mmap_base;
 121
 122         ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
 123         if (ret < 0) {
 124                 PERROR("Failed to get mmap read offset");
 125                 goto error;
 126         }
 127
 128         *addr = mmap_base + mmap_offset;
 129 error:
 130         return ret;
 131 }
 132
 133 /*
 134  * Take a snapshot of all the stream of a channel
 135  * RCU read-side lock must be held across this function to ensure existence of
 136  * channel.
 137  *
 138  * Returns 0 on success, < 0 on error
 139  */
 140 static int lttng_kconsumer_snapshot_channel(struct lttng_consumer_channel *channel,
 141                                             uint64_t key,
 142                                             char *path,
 143                                             uint64_t relayd_id,
 144                                             uint64_t nb_packets_per_stream)
 145 {
 146         int ret;
 147         struct lttng_consumer_stream *stream;
 148
 149         DBG("Kernel consumer snapshot channel %" PRIu64, key);
 150
 151         /* Prevent channel modifications while we perform the snapshot.*/
 152         pthread_mutex_lock(&channel->lock);
 153
 154         rcu_read_lock();
 155
 156         /* Splice is not supported yet for channel snapshot. */
 157         if (channel->output != CONSUMER_CHANNEL_MMAP) {
 158                 ERR("Unsupported output type for channel \"%s\": mmap output is required to record a snapshot",
 159                     channel->name);
 160                 ret = -1;
 161                 goto end;
 162         }
 163
 164         cds_list_for_each_entry (stream, &channel->streams.head, send_node) {
 165                 unsigned long consumed_pos, produced_pos;
 166
 167                 health_code_update();
 168
 169                 /*
 170                  * Lock stream because we are about to change its state.
 171                  */
 172                 pthread_mutex_lock(&stream->lock);
 173
 174                 LTTNG_ASSERT(channel->trace_chunk);
 175                 if (!lttng_trace_chunk_get(channel->trace_chunk)) {
 176                         /*
 177                          * Can't happen barring an internal error as the channel
 178                          * holds a reference to the trace chunk.
 179                          */
 180                         ERR("Failed to acquire reference to channel's trace chunk");
 181                         ret = -1;
 182                         goto end_unlock;
 183                 }
 184                 LTTNG_ASSERT(!stream->trace_chunk);
 185                 stream->trace_chunk = channel->trace_chunk;
 186
 187                 /*
 188                  * Assign the received relayd ID so we can use it for streaming. The streams
 189                  * are not visible to anyone so this is OK to change it.
 190                  */
 191                 stream->net_seq_idx = relayd_id;
 192                 channel->relayd_id = relayd_id;
 193                 if (relayd_id != (uint64_t) -1ULL) {
 194                         ret = consumer_send_relayd_stream(stream, path);
 195                         if (ret < 0) {
 196                                 ERR("sending stream to relayd");
 197                                 goto error_close_stream_output;
 198                         }
 199                 } else {
 200                         ret = consumer_stream_create_output_files(stream, false);
 201                         if (ret < 0) {
 202                                 goto error_close_stream_output;
 203                         }
 204                         DBG("Kernel consumer snapshot stream (%" PRIu64 ")", stream->key);
 205                 }
 206
 207                 ret = kernctl_buffer_flush_empty(stream->wait_fd);
 208                 if (ret < 0) {
 209                         /*
 210                          * Doing a buffer flush which does not take into
 211                          * account empty packets. This is not perfect
 212                          * for stream intersection, but required as a
 213                          * fall-back when "flush_empty" is not
 214                          * implemented by lttng-modules.
 215                          */
 216                         ret = kernctl_buffer_flush(stream->wait_fd);
 217                         if (ret < 0) {
 218                                 ERR("Failed to flush kernel stream");
 219                                 goto error_close_stream_output;
 220                         }
 221                         goto end_unlock;
 222                 }
 223
 224                 ret = lttng_kconsumer_take_snapshot(stream);
 225                 if (ret < 0) {
 226                         ERR("Taking kernel snapshot");
 227                         goto error_close_stream_output;
 228                 }
 229
 230                 ret = lttng_kconsumer_get_produced_snapshot(stream, &produced_pos);
 231                 if (ret < 0) {
 232                         ERR("Produced kernel snapshot position");
 233                         goto error_close_stream_output;
 234                 }
 235
 236                 ret = lttng_kconsumer_get_consumed_snapshot(stream, &consumed_pos);
 237                 if (ret < 0) {
 238                         ERR("Consumerd kernel snapshot position");
 239                         goto error_close_stream_output;
 240                 }
 241
 242                 consumed_pos = consumer_get_consume_start_pos(
 243                         consumed_pos, produced_pos, nb_packets_per_stream, stream->max_sb_size);
 244
 245                 while ((long) (consumed_pos - produced_pos) < 0) {
 246                         ssize_t read_len;
 247                         unsigned long len, padded_len;
 248                         const char *subbuf_addr;
 249                         struct lttng_buffer_view subbuf_view;
 250
 251                         health_code_update();
 252                         DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 253
 254                         ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
 255                         if (ret < 0) {
 256                                 if (ret != -EAGAIN) {
 257                                         PERROR("kernctl_get_subbuf snapshot");
 258                                         goto error_close_stream_output;
 259                                 }
 260                                 DBG("Kernel consumer get subbuf failed. Skipping it.");
 261                                 consumed_pos += stream->max_sb_size;
 262                                 stream->chan->lost_packets++;
 263                                 continue;
 264                         }
 265
 266                         ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
 267                         if (ret < 0) {
 268                                 ERR("Snapshot kernctl_get_subbuf_size");
 269                                 goto error_put_subbuf;
 270                         }
 271
 272                         ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
 273                         if (ret < 0) {
 274                                 ERR("Snapshot kernctl_get_padded_subbuf_size");
 275                                 goto error_put_subbuf;
 276                         }
 277
 278                         ret = get_current_subbuf_addr(stream, &subbuf_addr);
 279                         if (ret) {
 280                                 goto error_put_subbuf;
 281                         }
 282
 283                         subbuf_view = lttng_buffer_view_init(subbuf_addr, 0, padded_len);
 284                         read_len = lttng_consumer_on_read_subbuffer_mmap(
 285                                 stream, &subbuf_view, padded_len - len);
 286                         /*
 287                          * We write the padded len in local tracefiles but the data len
 288                          * when using a relay. Display the error but continue processing
 289                          * to try to release the subbuffer.
 290                          */
 291                         if (relayd_id != (uint64_t) -1ULL) {
 292                                 if (read_len != len) {
 293                                         ERR("Error sending to the relay (ret: %zd != len: %lu)",
 294                                             read_len,
 295                                             len);
 296                                 }
 297                         } else {
 298                                 if (read_len != padded_len) {
 299                                         ERR("Error writing to tracefile (ret: %zd != len: %lu)",
 300                                             read_len,
 301                                             padded_len);
 302                                 }
 303                         }
 304
 305                         ret = kernctl_put_subbuf(stream->wait_fd);
 306                         if (ret < 0) {
 307                                 ERR("Snapshot kernctl_put_subbuf");
 308                                 goto error_close_stream_output;
 309                         }
 310                         consumed_pos += stream->max_sb_size;
 311                 }
 312
 313                 consumer_stream_close_output(stream);
 314                 pthread_mutex_unlock(&stream->lock);
 315         }
 316
 317         /* All good! */
 318         ret = 0;
 319         goto end;
 320
 321 error_put_subbuf:
 322         ret = kernctl_put_subbuf(stream->wait_fd);
 323         if (ret < 0) {
 324                 ERR("Snapshot kernctl_put_subbuf error path");
 325         }
 326 error_close_stream_output:
 327         consumer_stream_close_output(stream);
 328 end_unlock:
 329         pthread_mutex_unlock(&stream->lock);
 330 end:
 331         rcu_read_unlock();
 332         pthread_mutex_unlock(&channel->lock);
 333         return ret;
 334 }
 335
 336 /*
 337  * Read the whole metadata available for a snapshot.
 338  * RCU read-side lock must be held across this function to ensure existence of
 339  * metadata_channel.
 340  *
 341  * Returns 0 on success, < 0 on error
 342  */
 343 static int lttng_kconsumer_snapshot_metadata(struct lttng_consumer_channel *metadata_channel,
 344                                              uint64_t key,
 345                                              char *path,
 346                                              uint64_t relayd_id,
 347                                              struct lttng_consumer_local_data *ctx)
 348 {
 349         int ret, use_relayd = 0;
 350         ssize_t ret_read;
 351         struct lttng_consumer_stream *metadata_stream;
 352
 353         LTTNG_ASSERT(ctx);
 354
 355         DBG("Kernel consumer snapshot metadata with key %" PRIu64 " at path %s", key, path);
 356
 357         rcu_read_lock();
 358
 359         metadata_stream = metadata_channel->metadata_stream;
 360         LTTNG_ASSERT(metadata_stream);
 361
 362         metadata_stream->read_subbuffer_ops.lock(metadata_stream);
 363         LTTNG_ASSERT(metadata_channel->trace_chunk);
 364         LTTNG_ASSERT(metadata_stream->trace_chunk);
 365
 366         /* Flag once that we have a valid relayd for the stream. */
 367         if (relayd_id != (uint64_t) -1ULL) {
 368                 use_relayd = 1;
 369         }
 370
 371         if (use_relayd) {
 372                 ret = consumer_send_relayd_stream(metadata_stream, path);
 373                 if (ret < 0) {
 374                         goto error_snapshot;
 375                 }
 376         } else {
 377                 ret = consumer_stream_create_output_files(metadata_stream, false);
 378                 if (ret < 0) {
 379                         goto error_snapshot;
 380                 }
 381         }
 382
 383         do {
 384                 health_code_update();
 385
 386                 ret_read = lttng_consumer_read_subbuffer(metadata_stream, ctx, true);
 387                 if (ret_read < 0) {
 388                         ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)", ret_read);
 389                         ret = ret_read;
 390                         goto error_snapshot;
 391                 }
 392         } while (ret_read > 0);
 393
 394         if (use_relayd) {
 395                 close_relayd_stream(metadata_stream);
 396                 metadata_stream->net_seq_idx = (uint64_t) -1ULL;
 397         } else {
 398                 if (metadata_stream->out_fd >= 0) {
 399                         ret = close(metadata_stream->out_fd);
 400                         if (ret < 0) {
 401                                 PERROR("Kernel consumer snapshot metadata close out_fd");
 402                                 /*
 403                                  * Don't go on error here since the snapshot was successful at this
 404                                  * point but somehow the close failed.
 405                                  */
 406                         }
 407                         metadata_stream->out_fd = -1;
 408                         lttng_trace_chunk_put(metadata_stream->trace_chunk);
 409                         metadata_stream->trace_chunk = nullptr;
 410                 }
 411         }
 412
 413         ret = 0;
 414 error_snapshot:
 415         metadata_stream->read_subbuffer_ops.unlock(metadata_stream);
 416         consumer_stream_destroy(metadata_stream, nullptr);
 417         metadata_channel->metadata_stream = nullptr;
 418         rcu_read_unlock();
 419         return ret;
 420 }
 421
 422 /*
 423  * Receive command from session daemon and process it.
 424  *
 425  * Return 1 on success else a negative value or 0.
 426  */
 427 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 428                              int sock,
 429                              struct pollfd *consumer_sockpoll)
 430 {
 431         int ret_func;
 432         enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 433         struct lttcomm_consumer_msg msg;
 434
 435         health_code_update();
 436
 437         {
 438                 ssize_t ret_recv;
 439
 440                 ret_recv = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 441                 if (ret_recv != sizeof(msg)) {
 442                         if (ret_recv > 0) {
 443                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 444                                 ret_recv = -1;
 445                         }
 446                         return ret_recv;
 447                 }
 448         }
 449
 450         health_code_update();
 451
 452         /* Deprecated command */
 453         LTTNG_ASSERT(msg.cmd_type != LTTNG_CONSUMER_STOP);
 454
 455         health_code_update();
 456
 457         /* relayd needs RCU read-side protection */
 458         rcu_read_lock();
 459
 460         switch (msg.cmd_type) {
 461         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 462         {
 463                 uint32_t major = msg.u.relayd_sock.major;
 464                 uint32_t minor = msg.u.relayd_sock.minor;
 465                 enum lttcomm_sock_proto protocol =
 466                         (enum lttcomm_sock_proto) msg.u.relayd_sock.relayd_socket_protocol;
 467
 468                 /* Session daemon status message are handled in the following call. */
 469                 consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 470                                            msg.u.relayd_sock.type,
 471                                            ctx,
 472                                            sock,
 473                                            consumer_sockpoll,
 474                                            msg.u.relayd_sock.session_id,
 475                                            msg.u.relayd_sock.relayd_session_id,
 476                                            major,
 477                                            minor,
 478                                            protocol);
 479                 goto end_nosignal;
 480         }
 481         case LTTNG_CONSUMER_ADD_CHANNEL:
 482         {
 483                 struct lttng_consumer_channel *new_channel;
 484                 int ret_send_status, ret_add_channel = 0;
 485                 const uint64_t chunk_id = msg.u.channel.chunk_id.value;
 486
 487                 health_code_update();
 488
 489                 /* First send a status message before receiving the fds. */
 490                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 491                 if (ret_send_status < 0) {
 492                         /* Somehow, the session daemon is not responding anymore. */
 493                         goto error_fatal;
 494                 }
 495
 496                 health_code_update();
 497
 498                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 499                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 500                                                         msg.u.channel.session_id,
 501                                                         msg.u.channel.chunk_id.is_set ? &chunk_id :
 502                                                                                         nullptr,
 503                                                         msg.u.channel.pathname,
 504                                                         msg.u.channel.name,
 505                                                         msg.u.channel.relayd_id,
 506                                                         msg.u.channel.output,
 507                                                         msg.u.channel.tracefile_size,
 508                                                         msg.u.channel.tracefile_count,
 509                                                         0,
 510                                                         msg.u.channel.monitor,
 511                                                         msg.u.channel.live_timer_interval,
 512                                                         msg.u.channel.is_live,
 513                                                         nullptr,
 514                                                         nullptr);
 515                 if (new_channel == nullptr) {
 516                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 517                         goto end_nosignal;
 518                 }
 519                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 520                 switch (msg.u.channel.output) {
 521                 case LTTNG_EVENT_SPLICE:
 522                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 523                         break;
 524                 case LTTNG_EVENT_MMAP:
 525                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 526                         break;
 527                 default:
 528                         ERR("Channel output unknown %d", msg.u.channel.output);
 529                         goto end_nosignal;
 530                 }
 531
 532                 /* Translate and save channel type. */
 533                 switch (msg.u.channel.type) {
 534                 case CONSUMER_CHANNEL_TYPE_DATA:
 535                 case CONSUMER_CHANNEL_TYPE_METADATA:
 536                         new_channel->type = (consumer_channel_type) msg.u.channel.type;
 537                         break;
 538                 default:
 539                         abort();
 540                         goto end_nosignal;
 541                 };
 542
 543                 health_code_update();
 544
 545                 if (ctx->on_recv_channel != nullptr) {
 546                         int ret_recv_channel = ctx->on_recv_channel(new_channel);
 547                         if (ret_recv_channel == 0) {
 548                                 ret_add_channel = consumer_add_channel(new_channel, ctx);
 549                         } else if (ret_recv_channel < 0) {
 550                                 goto end_nosignal;
 551                         }
 552                 } else {
 553                         ret_add_channel = consumer_add_channel(new_channel, ctx);
 554                 }
 555                 if (msg.u.channel.type == CONSUMER_CHANNEL_TYPE_DATA && !ret_add_channel) {
 556                         int monitor_start_ret;
 557
 558                         DBG("Consumer starting monitor timer");
 559                         consumer_timer_live_start(new_channel, msg.u.channel.live_timer_interval);
 560                         monitor_start_ret = consumer_timer_monitor_start(
 561                                 new_channel, msg.u.channel.monitor_timer_interval);
 562                         if (monitor_start_ret < 0) {
 563                                 ERR("Starting channel monitoring timer failed");
 564                                 goto end_nosignal;
 565                         }
 566                 }
 567
 568                 health_code_update();
 569
 570                 /* If we received an error in add_channel, we need to report it. */
 571                 if (ret_add_channel < 0) {
 572                         ret_send_status = consumer_send_status_msg(sock, ret_add_channel);
 573                         if (ret_send_status < 0) {
 574                                 goto error_fatal;
 575                         }
 576                         goto end_nosignal;
 577                 }
 578
 579                 goto end_nosignal;
 580         }
 581         case LTTNG_CONSUMER_ADD_STREAM:
 582         {
 583                 int fd;
 584                 struct lttng_pipe *stream_pipe;
 585                 struct lttng_consumer_stream *new_stream;
 586                 struct lttng_consumer_channel *channel;
 587                 int alloc_ret = 0;
 588                 int ret_send_status, ret_poll, ret_get_max_subbuf_size;
 589                 ssize_t ret_pipe_write, ret_recv;
 590
 591                 /*
 592                  * Get stream's channel reference. Needed when adding the stream to the
 593                  * global hash table.
 594                  */
 595                 channel = consumer_find_channel(msg.u.stream.channel_key);
 596                 if (!channel) {
 597                         /*
 598                          * We could not find the channel. Can happen if cpu hotplug
 599                          * happens while tearing down.
 600                          */
 601                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 602                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 603                 }
 604
 605                 health_code_update();
 606
 607                 /* First send a status message before receiving the fds. */
 608                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 609                 if (ret_send_status < 0) {
 610                         /* Somehow, the session daemon is not responding anymore. */
 611                         goto error_add_stream_fatal;
 612                 }
 613
 614                 health_code_update();
 615
 616                 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 617                         /* Channel was not found. */
 618                         goto error_add_stream_nosignal;
 619                 }
 620
 621                 /* Blocking call */
 622                 health_poll_entry();
 623                 ret_poll = lttng_consumer_poll_socket(consumer_sockpoll);
 624                 health_poll_exit();
 625                 if (ret_poll) {
 626                         goto error_add_stream_fatal;
 627                 }
 628
 629                 health_code_update();
 630
 631                 /* Get stream file descriptor from socket */
 632                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 633                 if (ret_recv != sizeof(fd)) {
 634                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 635                         ret_func = ret_recv;
 636                         goto end;
 637                 }
 638
 639                 health_code_update();
 640
 641                 /*
 642                  * Send status code to session daemon only if the recv works. If the
 643                  * above recv() failed, the session daemon is notified through the
 644                  * error socket and the teardown is eventually done.
 645                  */
 646                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 647                 if (ret_send_status < 0) {
 648                         /* Somehow, the session daemon is not responding anymore. */
 649                         goto error_add_stream_nosignal;
 650                 }
 651
 652                 health_code_update();
 653
 654                 pthread_mutex_lock(&channel->lock);
 655                 new_stream = consumer_stream_create(channel,
 656                                                     channel->key,
 657                                                     fd,
 658                                                     channel->name,
 659                                                     channel->relayd_id,
 660                                                     channel->session_id,
 661                                                     channel->trace_chunk,
 662                                                     msg.u.stream.cpu,
 663                                                     &alloc_ret,
 664                                                     channel->type,
 665                                                     channel->monitor);
 666                 if (new_stream == nullptr) {
 667                         switch (alloc_ret) {
 668                         case -ENOMEM:
 669                         case -EINVAL:
 670                         default:
 671                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 672                                 break;
 673                         }
 674                         pthread_mutex_unlock(&channel->lock);
 675                         goto error_add_stream_nosignal;
 676                 }
 677
 678                 new_stream->wait_fd = fd;
 679                 ret_get_max_subbuf_size =
 680                         kernctl_get_max_subbuf_size(new_stream->wait_fd, &new_stream->max_sb_size);
 681                 if (ret_get_max_subbuf_size < 0) {
 682                         pthread_mutex_unlock(&channel->lock);
 683                         ERR("Failed to get kernel maximal subbuffer size");
 684                         goto error_add_stream_nosignal;
 685                 }
 686
 687                 consumer_stream_update_channel_attributes(new_stream, channel);
 688
 689                 /*
 690                  * We've just assigned the channel to the stream so increment the
 691                  * refcount right now. We don't need to increment the refcount for
 692                  * streams in no monitor because we handle manually the cleanup of
 693                  * those. It is very important to make sure there is NO prior
 694                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 695                  */
 696                 if (channel->monitor) {
 697                         uatomic_inc(&new_stream->chan->refcount);
 698                 }
 699
 700                 /*
 701                  * The buffer flush is done on the session daemon side for the kernel
 702                  * so no need for the stream "hangup_flush_done" variable to be
 703                  * tracked. This is important for a kernel stream since we don't rely
 704                  * on the flush state of the stream to read data. It's not the case for
 705                  * user space tracing.
 706                  */
 707                 new_stream->hangup_flush_done = 0;
 708
 709                 health_code_update();
 710
 711                 pthread_mutex_lock(&new_stream->lock);
 712                 if (ctx->on_recv_stream) {
 713                         int ret_recv_stream = ctx->on_recv_stream(new_stream);
 714                         if (ret_recv_stream < 0) {
 715                                 pthread_mutex_unlock(&new_stream->lock);
 716                                 pthread_mutex_unlock(&channel->lock);
 717                                 consumer_stream_free(new_stream);
 718                                 goto error_add_stream_nosignal;
 719                         }
 720                 }
 721                 health_code_update();
 722
 723                 if (new_stream->metadata_flag) {
 724                         channel->metadata_stream = new_stream;
 725                 }
 726
 727                 /* Do not monitor this stream. */
 728                 if (!channel->monitor) {
 729                         DBG("Kernel consumer add stream %s in no monitor mode with "
 730                             "relayd id %" PRIu64,
 731                             new_stream->name,
 732                             new_stream->net_seq_idx);
 733                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 734                         pthread_mutex_unlock(&new_stream->lock);
 735                         pthread_mutex_unlock(&channel->lock);
 736                         goto end_add_stream;
 737                 }
 738
 739                 /* Send stream to relayd if the stream has an ID. */
 740                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 741                         int ret_send_relayd_stream;
 742
 743                         ret_send_relayd_stream =
 744                                 consumer_send_relayd_stream(new_stream, new_stream->chan->pathname);
 745                         if (ret_send_relayd_stream < 0) {
 746                                 pthread_mutex_unlock(&new_stream->lock);
 747                                 pthread_mutex_unlock(&channel->lock);
 748                                 consumer_stream_free(new_stream);
 749                                 goto error_add_stream_nosignal;
 750                         }
 751
 752                         /*
 753                          * If adding an extra stream to an already
 754                          * existing channel (e.g. cpu hotplug), we need
 755                          * to send the "streams_sent" command to relayd.
 756                          */
 757                         if (channel->streams_sent_to_relayd) {
 758                                 int ret_send_relayd_streams_sent;
 759
 760                                 ret_send_relayd_streams_sent =
 761                                         consumer_send_relayd_streams_sent(new_stream->net_seq_idx);
 762                                 if (ret_send_relayd_streams_sent < 0) {
 763                                         pthread_mutex_unlock(&new_stream->lock);
 764                                         pthread_mutex_unlock(&channel->lock);
 765                                         goto error_add_stream_nosignal;
 766                                 }
 767                         }
 768                 }
 769                 pthread_mutex_unlock(&new_stream->lock);
 770                 pthread_mutex_unlock(&channel->lock);
 771
 772                 /* Get the right pipe where the stream will be sent. */
 773                 if (new_stream->metadata_flag) {
 774                         consumer_add_metadata_stream(new_stream);
 775                         stream_pipe = ctx->consumer_metadata_pipe;
 776                 } else {
 777                         consumer_add_data_stream(new_stream);
 778                         stream_pipe = ctx->consumer_data_pipe;
 779                 }
 780
 781                 /* Visible to other threads */
 782                 new_stream->globally_visible = 1;
 783
 784                 health_code_update();
 785
 786                 ret_pipe_write =
 787                         lttng_pipe_write(stream_pipe, &new_stream, sizeof(new_stream)); /* NOLINT
 788                                                                                            sizeof
 789                                                                                            used on a
 790                                                                                            pointer.
 791                                                                                          */
 792                 if (ret_pipe_write < 0) {
 793                         ERR("Consumer write %s stream to pipe %d",
 794                             new_stream->metadata_flag ? "metadata" : "data",
 795                             lttng_pipe_get_writefd(stream_pipe));
 796                         if (new_stream->metadata_flag) {
 797                                 consumer_del_stream_for_metadata(new_stream);
 798                         } else {
 799                                 consumer_del_stream_for_data(new_stream);
 800                         }
 801                         goto error_add_stream_nosignal;
 802                 }
 803
 804                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
 805                     new_stream->name,
 806                     fd,
 807                     new_stream->chan->pathname,
 808                     new_stream->relayd_stream_id);
 809         end_add_stream:
 810                 break;
 811         error_add_stream_nosignal:
 812                 goto end_nosignal;
 813         error_add_stream_fatal:
 814                 goto error_fatal;
 815         }
 816         case LTTNG_CONSUMER_STREAMS_SENT:
 817         {
 818                 struct lttng_consumer_channel *channel;
 819                 int ret_send_status;
 820
 821                 /*
 822                  * Get stream's channel reference. Needed when adding the stream to the
 823                  * global hash table.
 824                  */
 825                 channel = consumer_find_channel(msg.u.sent_streams.channel_key);
 826                 if (!channel) {
 827                         /*
 828                          * We could not find the channel. Can happen if cpu hotplug
 829                          * happens while tearing down.
 830                          */
 831                         ERR("Unable to find channel key %" PRIu64, msg.u.sent_streams.channel_key);
 832                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 833                 }
 834
 835                 health_code_update();
 836
 837                 /*
 838                  * Send status code to session daemon.
 839                  */
 840                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 841                 if (ret_send_status < 0 || ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 842                         /* Somehow, the session daemon is not responding anymore. */
 843                         goto error_streams_sent_nosignal;
 844                 }
 845
 846                 health_code_update();
 847
 848                 /*
 849                  * We should not send this message if we don't monitor the
 850                  * streams in this channel.
 851                  */
 852                 if (!channel->monitor) {
 853                         goto end_error_streams_sent;
 854                 }
 855
 856                 health_code_update();
 857                 /* Send stream to relayd if the stream has an ID. */
 858                 if (msg.u.sent_streams.net_seq_idx != (uint64_t) -1ULL) {
 859                         int ret_send_relay_streams;
 860
 861                         ret_send_relay_streams =
 862                                 consumer_send_relayd_streams_sent(msg.u.sent_streams.net_seq_idx);
 863                         if (ret_send_relay_streams < 0) {
 864                                 goto error_streams_sent_nosignal;
 865                         }
 866                         channel->streams_sent_to_relayd = true;
 867                 }
 868         end_error_streams_sent:
 869                 break;
 870         error_streams_sent_nosignal:
 871                 goto end_nosignal;
 872         }
 873         case LTTNG_CONSUMER_UPDATE_STREAM:
 874         {
 875                 rcu_read_unlock();
 876                 return -ENOSYS;
 877         }
 878         case LTTNG_CONSUMER_DESTROY_RELAYD:
 879         {
 880                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 881                 struct consumer_relayd_sock_pair *relayd;
 882                 int ret_send_status;
 883
 884                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 885
 886                 /* Get relayd reference if exists. */
 887                 relayd = consumer_find_relayd(index);
 888                 if (relayd == nullptr) {
 889                         DBG("Unable to find relayd %" PRIu64, index);
 890                         ret_code = LTTCOMM_CONSUMERD_RELAYD_FAIL;
 891                 }
 892
 893                 /*
 894                  * Each relayd socket pair has a refcount of stream attached to it
 895                  * which tells if the relayd is still active or not depending on the
 896                  * refcount value.
 897                  *
 898                  * This will set the destroy flag of the relayd object and destroy it
 899                  * if the refcount reaches zero when called.
 900                  *
 901                  * The destroy can happen either here or when a stream fd hangs up.
 902                  */
 903                 if (relayd) {
 904                         consumer_flag_relayd_for_destroy(relayd);
 905                 }
 906
 907                 health_code_update();
 908
 909                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 910                 if (ret_send_status < 0) {
 911                         /* Somehow, the session daemon is not responding anymore. */
 912                         goto error_fatal;
 913                 }
 914
 915                 goto end_nosignal;
 916         }
 917         case LTTNG_CONSUMER_DATA_PENDING:
 918         {
 919                 int32_t ret_data_pending;
 920                 uint64_t id = msg.u.data_pending.session_id;
 921                 ssize_t ret_send;
 922
 923                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 924
 925                 ret_data_pending = consumer_data_pending(id);
 926
 927                 health_code_update();
 928
 929                 /* Send back returned value to session daemon */
 930                 ret_send =
 931                         lttcomm_send_unix_sock(sock, &ret_data_pending, sizeof(ret_data_pending));
 932                 if (ret_send < 0) {
 933                         PERROR("send data pending ret code");
 934                         goto error_fatal;
 935                 }
 936
 937                 /*
 938                  * No need to send back a status message since the data pending
 939                  * returned value is the response.
 940                  */
 941                 break;
 942         }
 943         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 944         {
 945                 struct lttng_consumer_channel *channel;
 946                 uint64_t key = msg.u.snapshot_channel.key;
 947                 int ret_send_status;
 948
 949                 channel = consumer_find_channel(key);
 950                 if (!channel) {
 951                         ERR("Channel %" PRIu64 " not found", key);
 952                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 953                 } else {
 954                         if (msg.u.snapshot_channel.metadata == 1) {
 955                                 int ret_snapshot;
 956
 957                                 ret_snapshot = lttng_kconsumer_snapshot_metadata(
 958                                         channel,
 959                                         key,
 960                                         msg.u.snapshot_channel.pathname,
 961                                         msg.u.snapshot_channel.relayd_id,
 962                                         ctx);
 963                                 if (ret_snapshot < 0) {
 964                                         ERR("Snapshot metadata failed");
 965                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 966                                 }
 967                         } else {
 968                                 int ret_snapshot;
 969
 970                                 ret_snapshot = lttng_kconsumer_snapshot_channel(
 971                                         channel,
 972                                         key,
 973                                         msg.u.snapshot_channel.pathname,
 974                                         msg.u.snapshot_channel.relayd_id,
 975                                         msg.u.snapshot_channel.nb_packets_per_stream);
 976                                 if (ret_snapshot < 0) {
 977                                         ERR("Snapshot channel failed");
 978                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 979                                 }
 980                         }
 981                 }
 982                 health_code_update();
 983
 984                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 985                 if (ret_send_status < 0) {
 986                         /* Somehow, the session daemon is not responding anymore. */
 987                         goto end_nosignal;
 988                 }
 989                 break;
 990         }
 991         case LTTNG_CONSUMER_DESTROY_CHANNEL:
 992         {
 993                 uint64_t key = msg.u.destroy_channel.key;
 994                 struct lttng_consumer_channel *channel;
 995                 int ret_send_status;
 996
 997                 channel = consumer_find_channel(key);
 998                 if (!channel) {
 999                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
1000                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1001                 }
1002
1003                 health_code_update();
1004
1005                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1006                 if (ret_send_status < 0) {
1007                         /* Somehow, the session daemon is not responding anymore. */
1008                         goto end_destroy_channel;
1009                 }
1010
1011                 health_code_update();
1012
1013                 /* Stop right now if no channel was found. */
1014                 if (!channel) {
1015                         goto end_destroy_channel;
1016                 }
1017
1018                 /*
1019                  * This command should ONLY be issued for channel with streams set in
1020                  * no monitor mode.
1021                  */
1022                 LTTNG_ASSERT(!channel->monitor);
1023
1024                 /*
1025                  * The refcount should ALWAYS be 0 in the case of a channel in no
1026                  * monitor mode.
1027                  */
1028                 LTTNG_ASSERT(!uatomic_sub_return(&channel->refcount, 1));
1029
1030                 consumer_del_channel(channel);
1031         end_destroy_channel:
1032                 goto end_nosignal;
1033         }
1034         case LTTNG_CONSUMER_DISCARDED_EVENTS:
1035         {
1036                 ssize_t ret;
1037                 uint64_t count;
1038                 struct lttng_consumer_channel *channel;
1039                 uint64_t id = msg.u.discarded_events.session_id;
1040                 uint64_t key = msg.u.discarded_events.channel_key;
1041
1042                 DBG("Kernel consumer discarded events command for session id %" PRIu64
1043                     ", channel key %" PRIu64,
1044                     id,
1045                     key);
1046
1047                 channel = consumer_find_channel(key);
1048                 if (!channel) {
1049                         ERR("Kernel consumer discarded events channel %" PRIu64 " not found", key);
1050                         count = 0;
1051                 } else {
1052                         count = channel->discarded_events;
1053                 }
1054
1055                 health_code_update();
1056
1057                 /* Send back returned value to session daemon */
1058                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1059                 if (ret < 0) {
1060                         PERROR("send discarded events");
1061                         goto error_fatal;
1062                 }
1063
1064                 break;
1065         }
1066         case LTTNG_CONSUMER_LOST_PACKETS:
1067         {
1068                 ssize_t ret;
1069                 uint64_t count;
1070                 struct lttng_consumer_channel *channel;
1071                 uint64_t id = msg.u.lost_packets.session_id;
1072                 uint64_t key = msg.u.lost_packets.channel_key;
1073
1074                 DBG("Kernel consumer lost packets command for session id %" PRIu64
1075                     ", channel key %" PRIu64,
1076                     id,
1077                     key);
1078
1079                 channel = consumer_find_channel(key);
1080                 if (!channel) {
1081                         ERR("Kernel consumer lost packets channel %" PRIu64 " not found", key);
1082                         count = 0;
1083                 } else {
1084                         count = channel->lost_packets;
1085                 }
1086
1087                 health_code_update();
1088
1089                 /* Send back returned value to session daemon */
1090                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1091                 if (ret < 0) {
1092                         PERROR("send lost packets");
1093                         goto error_fatal;
1094                 }
1095
1096                 break;
1097         }
1098         case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
1099         {
1100                 int channel_monitor_pipe;
1101                 int ret_send_status, ret_set_channel_monitor_pipe;
1102                 ssize_t ret_recv;
1103
1104                 ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1105                 /* Successfully received the command's type. */
1106                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1107                 if (ret_send_status < 0) {
1108                         goto error_fatal;
1109                 }
1110
1111                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &channel_monitor_pipe, 1);
1112                 if (ret_recv != sizeof(channel_monitor_pipe)) {
1113                         ERR("Failed to receive channel monitor pipe");
1114                         goto error_fatal;
1115                 }
1116
1117                 DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
1118                 ret_set_channel_monitor_pipe =
1119                         consumer_timer_thread_set_channel_monitor_pipe(channel_monitor_pipe);
1120                 if (!ret_set_channel_monitor_pipe) {
1121                         int flags;
1122                         int ret_fcntl;
1123
1124                         ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1125                         /* Set the pipe as non-blocking. */
1126                         ret_fcntl = fcntl(channel_monitor_pipe, F_GETFL, 0);
1127                         if (ret_fcntl == -1) {
1128                                 PERROR("fcntl get flags of the channel monitoring pipe");
1129                                 goto error_fatal;
1130                         }
1131                         flags = ret_fcntl;
1132
1133                         ret_fcntl = fcntl(channel_monitor_pipe, F_SETFL, flags | O_NONBLOCK);
1134                         if (ret_fcntl == -1) {
1135                                 PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
1136                                 goto error_fatal;
1137                         }
1138                         DBG("Channel monitor pipe set as non-blocking");
1139                 } else {
1140                         ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
1141                 }
1142                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1143                 if (ret_send_status < 0) {
1144                         goto error_fatal;
1145                 }
1146                 break;
1147         }
1148         case LTTNG_CONSUMER_ROTATE_CHANNEL:
1149         {
1150                 struct lttng_consumer_channel *channel;
1151                 uint64_t key = msg.u.rotate_channel.key;
1152                 int ret_send_status;
1153
1154                 DBG("Consumer rotate channel %" PRIu64, key);
1155
1156                 channel = consumer_find_channel(key);
1157                 if (!channel) {
1158                         ERR("Channel %" PRIu64 " not found", key);
1159                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1160                 } else {
1161                         /*
1162                          * Sample the rotate position of all the streams in this channel.
1163                          */
1164                         int ret_rotate_channel;
1165
1166                         ret_rotate_channel = lttng_consumer_rotate_channel(
1167                                 channel, key, msg.u.rotate_channel.relayd_id);
1168                         if (ret_rotate_channel < 0) {
1169                                 ERR("Rotate channel failed");
1170                                 ret_code = LTTCOMM_CONSUMERD_ROTATION_FAIL;
1171                         }
1172
1173                         health_code_update();
1174                 }
1175
1176                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1177                 if (ret_send_status < 0) {
1178                         /* Somehow, the session daemon is not responding anymore. */
1179                         goto error_rotate_channel;
1180                 }
1181                 if (channel) {
1182                         /* Rotate the streams that are ready right now. */
1183                         int ret_rotate;
1184
1185                         ret_rotate = lttng_consumer_rotate_ready_streams(channel, key);
1186                         if (ret_rotate < 0) {
1187                                 ERR("Rotate ready streams failed");
1188                         }
1189                 }
1190                 break;
1191         error_rotate_channel:
1192                 goto end_nosignal;
1193         }
1194         case LTTNG_CONSUMER_CLEAR_CHANNEL:
1195         {
1196                 struct lttng_consumer_channel *channel;
1197                 uint64_t key = msg.u.clear_channel.key;
1198                 int ret_send_status;
1199
1200                 channel = consumer_find_channel(key);
1201                 if (!channel) {
1202                         DBG("Channel %" PRIu64 " not found", key);
1203                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1204                 } else {
1205                         int ret_clear_channel;
1206
1207                         ret_clear_channel = lttng_consumer_clear_channel(channel);
1208                         if (ret_clear_channel) {
1209                                 ERR("Clear channel failed");
1210                                 ret_code = (lttcomm_return_code) ret_clear_channel;
1211                         }
1212
1213                         health_code_update();
1214                 }
1215
1216                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1217                 if (ret_send_status < 0) {
1218                         /* Somehow, the session daemon is not responding anymore. */
1219                         goto end_nosignal;
1220                 }
1221
1222                 break;
1223         }
1224         case LTTNG_CONSUMER_INIT:
1225         {
1226                 int ret_send_status;
1227                 lttng_uuid sessiond_uuid;
1228
1229                 std::copy(std::begin(msg.u.init.sessiond_uuid),
1230                           std::end(msg.u.init.sessiond_uuid),
1231                           sessiond_uuid.begin());
1232
1233                 ret_code = lttng_consumer_init_command(ctx, sessiond_uuid);
1234                 health_code_update();
1235                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1236                 if (ret_send_status < 0) {
1237                         /* Somehow, the session daemon is not responding anymore. */
1238                         goto end_nosignal;
1239                 }
1240                 break;
1241         }
1242         case LTTNG_CONSUMER_CREATE_TRACE_CHUNK:
1243         {
1244                 const struct lttng_credentials credentials = {
1245                         .uid = LTTNG_OPTIONAL_INIT_VALUE(
1246                                 msg.u.create_trace_chunk.credentials.value.uid),
1247                         .gid = LTTNG_OPTIONAL_INIT_VALUE(
1248                                 msg.u.create_trace_chunk.credentials.value.gid),
1249                 };
1250                 const bool is_local_trace = !msg.u.create_trace_chunk.relayd_id.is_set;
1251                 const uint64_t relayd_id = msg.u.create_trace_chunk.relayd_id.value;
1252                 const char *chunk_override_name = *msg.u.create_trace_chunk.override_name ?
1253                         msg.u.create_trace_chunk.override_name :
1254                         nullptr;
1255                 struct lttng_directory_handle *chunk_directory_handle = nullptr;
1256
1257                 /*
1258                  * The session daemon will only provide a chunk directory file
1259                  * descriptor for local traces.
1260                  */
1261                 if (is_local_trace) {
1262                         int chunk_dirfd;
1263                         int ret_send_status;
1264                         ssize_t ret_recv;
1265
1266                         /* Acnowledge the reception of the command. */
1267                         ret_send_status = consumer_send_status_msg(sock, LTTCOMM_CONSUMERD_SUCCESS);
1268                         if (ret_send_status < 0) {
1269                                 /* Somehow, the session daemon is not responding anymore. */
1270                                 goto end_nosignal;
1271                         }
1272
1273                         ret_recv = lttcomm_recv_fds_unix_sock(sock, &chunk_dirfd, 1);
1274                         if (ret_recv != sizeof(chunk_dirfd)) {
1275                                 ERR("Failed to receive trace chunk directory file descriptor");
1276                                 goto error_fatal;
1277                         }
1278
1279                         DBG("Received trace chunk directory fd (%d)", chunk_dirfd);
1280                         chunk_directory_handle =
1281                                 lttng_directory_handle_create_from_dirfd(chunk_dirfd);
1282                         if (!chunk_directory_handle) {
1283                                 ERR("Failed to initialize chunk directory handle from directory file descriptor");
1284                                 if (close(chunk_dirfd)) {
1285                                         PERROR("Failed to close chunk directory file descriptor");
1286                                 }
1287                                 goto error_fatal;
1288                         }
1289                 }
1290
1291                 ret_code = lttng_consumer_create_trace_chunk(
1292                         !is_local_trace ? &relayd_id : nullptr,
1293                         msg.u.create_trace_chunk.session_id,
1294                         msg.u.create_trace_chunk.chunk_id,
1295                         (time_t) msg.u.create_trace_chunk.creation_timestamp,
1296                         chunk_override_name,
1297                         msg.u.create_trace_chunk.credentials.is_set ? &credentials : nullptr,
1298                         chunk_directory_handle);
1299                 lttng_directory_handle_put(chunk_directory_handle);
1300                 goto end_msg_sessiond;
1301         }
1302         case LTTNG_CONSUMER_CLOSE_TRACE_CHUNK:
1303         {
1304                 enum lttng_trace_chunk_command_type close_command =
1305                         (lttng_trace_chunk_command_type) msg.u.close_trace_chunk.close_command.value;
1306                 const uint64_t relayd_id = msg.u.close_trace_chunk.relayd_id.value;
1307                 struct lttcomm_consumer_close_trace_chunk_reply reply;
1308                 char path[LTTNG_PATH_MAX];
1309                 ssize_t ret_send;
1310
1311                 ret_code = lttng_consumer_close_trace_chunk(
1312                         msg.u.close_trace_chunk.relayd_id.is_set ? &relayd_id : nullptr,
1313                         msg.u.close_trace_chunk.session_id,
1314                         msg.u.close_trace_chunk.chunk_id,
1315                         (time_t) msg.u.close_trace_chunk.close_timestamp,
1316                         msg.u.close_trace_chunk.close_command.is_set ? &close_command : nullptr,
1317                         path);
1318                 reply.ret_code = ret_code;
1319                 reply.path_length = strlen(path) + 1;
1320                 ret_send = lttcomm_send_unix_sock(sock, &reply, sizeof(reply));
1321                 if (ret_send != sizeof(reply)) {
1322                         goto error_fatal;
1323                 }
1324                 ret_send = lttcomm_send_unix_sock(sock, path, reply.path_length);
1325                 if (ret_send != reply.path_length) {
1326                         goto error_fatal;
1327                 }
1328                 goto end_nosignal;
1329         }
1330         case LTTNG_CONSUMER_TRACE_CHUNK_EXISTS:
1331         {
1332                 const uint64_t relayd_id = msg.u.trace_chunk_exists.relayd_id.value;
1333
1334                 ret_code = lttng_consumer_trace_chunk_exists(
1335                         msg.u.trace_chunk_exists.relayd_id.is_set ? &relayd_id : nullptr,
1336                         msg.u.trace_chunk_exists.session_id,
1337                         msg.u.trace_chunk_exists.chunk_id);
1338                 goto end_msg_sessiond;
1339         }
1340         case LTTNG_CONSUMER_OPEN_CHANNEL_PACKETS:
1341         {
1342                 const uint64_t key = msg.u.open_channel_packets.key;
1343                 struct lttng_consumer_channel *channel = consumer_find_channel(key);
1344
1345                 if (channel) {
1346                         pthread_mutex_lock(&channel->lock);
1347                         ret_code = lttng_consumer_open_channel_packets(channel);
1348                         pthread_mutex_unlock(&channel->lock);
1349                 } else {
1350                         WARN("Channel %" PRIu64 " not found", key);
1351                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1352                 }
1353
1354                 health_code_update();
1355                 goto end_msg_sessiond;
1356         }
1357         default:
1358                 goto end_nosignal;
1359         }
1360
1361 end_nosignal:
1362         /*
1363          * Return 1 to indicate success since the 0 value can be a socket
1364          * shutdown during the recv() or send() call.
1365          */
1366         ret_func = 1;
1367         goto end;
1368 error_fatal:
1369         /* This will issue a consumer stop. */
1370         ret_func = -1;
1371         goto end;
1372 end_msg_sessiond:
1373         /*
1374          * The returned value here is not useful since either way we'll return 1 to
1375          * the caller because the session daemon socket management is done
1376          * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1377          */
1378         {
1379                 int ret_send_status;
1380
1381                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1382                 if (ret_send_status < 0) {
1383                         goto error_fatal;
1384                 }
1385         }
1386
1387         ret_func = 1;
1388
1389 end:
1390         health_code_update();
1391         rcu_read_unlock();
1392         return ret_func;
1393 }
1394
1395 /*
1396  * Sync metadata meaning request them to the session daemon and snapshot to the
1397  * metadata thread can consumer them.
1398  *
1399  * Metadata stream lock MUST be acquired.
1400  */
1401 enum sync_metadata_status lttng_kconsumer_sync_metadata(struct lttng_consumer_stream *metadata)
1402 {
1403         int ret;
1404         enum sync_metadata_status status;
1405
1406         LTTNG_ASSERT(metadata);
1407
1408         ret = kernctl_buffer_flush(metadata->wait_fd);
1409         if (ret < 0) {
1410                 ERR("Failed to flush kernel stream");
1411                 status = SYNC_METADATA_STATUS_ERROR;
1412                 goto end;
1413         }
1414
1415         ret = kernctl_snapshot(metadata->wait_fd);
1416         if (ret < 0) {
1417                 if (errno == EAGAIN) {
1418                         /* No new metadata, exit. */
1419                         DBG("Sync metadata, no new kernel metadata");
1420                         status = SYNC_METADATA_STATUS_NO_DATA;
1421                 } else {
1422                         ERR("Sync metadata, taking kernel snapshot failed.");
1423                         status = SYNC_METADATA_STATUS_ERROR;
1424                 }
1425         } else {
1426                 status = SYNC_METADATA_STATUS_NEW_DATA;
1427         }
1428
1429 end:
1430         return status;
1431 }
1432
1433 static int extract_common_subbuffer_info(struct lttng_consumer_stream *stream,
1434                                          struct stream_subbuffer *subbuf)
1435 {
1436         int ret;
1437
1438         ret = kernctl_get_subbuf_size(stream->wait_fd, &subbuf->info.data.subbuf_size);
1439         if (ret) {
1440                 goto end;
1441         }
1442
1443         ret = kernctl_get_padded_subbuf_size(stream->wait_fd,
1444                                              &subbuf->info.data.padded_subbuf_size);
1445         if (ret) {
1446                 goto end;
1447         }
1448
1449 end:
1450         return ret;
1451 }
1452
1453 static int extract_metadata_subbuffer_info(struct lttng_consumer_stream *stream,
1454                                            struct stream_subbuffer *subbuf)
1455 {
1456         int ret;
1457
1458         ret = extract_common_subbuffer_info(stream, subbuf);
1459         if (ret) {
1460                 goto end;
1461         }
1462
1463         ret = kernctl_get_metadata_version(stream->wait_fd, &subbuf->info.metadata.version);
1464         if (ret) {
1465                 goto end;
1466         }
1467
1468 end:
1469         return ret;
1470 }
1471
1472 static int extract_data_subbuffer_info(struct lttng_consumer_stream *stream,
1473                                        struct stream_subbuffer *subbuf)
1474 {
1475         int ret;
1476
1477         ret = extract_common_subbuffer_info(stream, subbuf);
1478         if (ret) {
1479                 goto end;
1480         }
1481
1482         ret = kernctl_get_packet_size(stream->wait_fd, &subbuf->info.data.packet_size);
1483         if (ret < 0) {
1484                 PERROR("Failed to get sub-buffer packet size");
1485                 goto end;
1486         }
1487
1488         ret = kernctl_get_content_size(stream->wait_fd, &subbuf->info.data.content_size);
1489         if (ret < 0) {
1490                 PERROR("Failed to get sub-buffer content size");
1491                 goto end;
1492         }
1493
1494         ret = kernctl_get_timestamp_begin(stream->wait_fd, &subbuf->info.data.timestamp_begin);
1495         if (ret < 0) {
1496                 PERROR("Failed to get sub-buffer begin timestamp");
1497                 goto end;
1498         }
1499
1500         ret = kernctl_get_timestamp_end(stream->wait_fd, &subbuf->info.data.timestamp_end);
1501         if (ret < 0) {
1502                 PERROR("Failed to get sub-buffer end timestamp");
1503                 goto end;
1504         }
1505
1506         ret = kernctl_get_events_discarded(stream->wait_fd, &subbuf->info.data.events_discarded);
1507         if (ret) {
1508                 PERROR("Failed to get sub-buffer events discarded count");
1509                 goto end;
1510         }
1511
1512         ret = kernctl_get_sequence_number(stream->wait_fd,
1513                                           &subbuf->info.data.sequence_number.value);
1514         if (ret) {
1515                 /* May not be supported by older LTTng-modules. */
1516                 if (ret != -ENOTTY) {
1517                         PERROR("Failed to get sub-buffer sequence number");
1518                         goto end;
1519                 }
1520         } else {
1521                 subbuf->info.data.sequence_number.is_set = true;
1522         }
1523
1524         ret = kernctl_get_stream_id(stream->wait_fd, &subbuf->info.data.stream_id);
1525         if (ret < 0) {
1526                 PERROR("Failed to get stream id");
1527                 goto end;
1528         }
1529
1530         ret = kernctl_get_instance_id(stream->wait_fd, &subbuf->info.data.stream_instance_id.value);
1531         if (ret) {
1532                 /* May not be supported by older LTTng-modules. */
1533                 if (ret != -ENOTTY) {
1534                         PERROR("Failed to get stream instance id");
1535                         goto end;
1536                 }
1537         } else {
1538                 subbuf->info.data.stream_instance_id.is_set = true;
1539         }
1540 end:
1541         return ret;
1542 }
1543
1544 static enum get_next_subbuffer_status get_subbuffer_common(struct lttng_consumer_stream *stream,
1545                                                            struct stream_subbuffer *subbuffer)
1546 {
1547         int ret;
1548         enum get_next_subbuffer_status status;
1549
1550         ret = kernctl_get_next_subbuf(stream->wait_fd);
1551         switch (ret) {
1552         case 0:
1553                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1554                 break;
1555         case -ENODATA:
1556         case -EAGAIN:
1557                 /*
1558                  * The caller only expects -ENODATA when there is no data to
1559                  * read, but the kernel tracer returns -EAGAIN when there is
1560                  * currently no data for a non-finalized stream, and -ENODATA
1561                  * when there is no data for a finalized stream. Those can be
1562                  * combined into a -ENODATA return value.
1563                  */
1564                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1565                 goto end;
1566         default:
1567                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1568                 goto end;
1569         }
1570
1571         ret = stream->read_subbuffer_ops.extract_subbuffer_info(stream, subbuffer);
1572         if (ret) {
1573                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1574         }
1575 end:
1576         return status;
1577 }
1578
1579 static enum get_next_subbuffer_status
1580 get_next_subbuffer_splice(struct lttng_consumer_stream *stream, struct stream_subbuffer *subbuffer)
1581 {
1582         const enum get_next_subbuffer_status status = get_subbuffer_common(stream, subbuffer);
1583
1584         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1585                 goto end;
1586         }
1587
1588         subbuffer->buffer.fd = stream->wait_fd;
1589 end:
1590         return status;
1591 }
1592
1593 static enum get_next_subbuffer_status get_next_subbuffer_mmap(struct lttng_consumer_stream *stream,
1594                                                               struct stream_subbuffer *subbuffer)
1595 {
1596         int ret;
1597         enum get_next_subbuffer_status status;
1598         const char *addr;
1599
1600         status = get_subbuffer_common(stream, subbuffer);
1601         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1602                 goto end;
1603         }
1604
1605         ret = get_current_subbuf_addr(stream, &addr);
1606         if (ret) {
1607                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1608                 goto end;
1609         }
1610
1611         subbuffer->buffer.buffer =
1612                 lttng_buffer_view_init(addr, 0, subbuffer->info.data.padded_subbuf_size);
1613 end:
1614         return status;
1615 }
1616
1617 static enum get_next_subbuffer_status
1618 get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
1619                                   struct stream_subbuffer *subbuffer)
1620 {
1621         int ret;
1622         const char *addr;
1623         bool coherent;
1624         enum get_next_subbuffer_status status;
1625
1626         ret = kernctl_get_next_subbuf_metadata_check(stream->wait_fd, &coherent);
1627         if (ret) {
1628                 goto end;
1629         }
1630
1631         ret = stream->read_subbuffer_ops.extract_subbuffer_info(stream, subbuffer);
1632         if (ret) {
1633                 goto end;
1634         }
1635
1636         LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
1637
1638         ret = get_current_subbuf_addr(stream, &addr);
1639         if (ret) {
1640                 goto end;
1641         }
1642
1643         subbuffer->buffer.buffer =
1644                 lttng_buffer_view_init(addr, 0, subbuffer->info.data.padded_subbuf_size);
1645         DBG("Got metadata packet with padded_subbuf_size = %lu, coherent = %s",
1646             subbuffer->info.metadata.padded_subbuf_size,
1647             coherent ? "true" : "false");
1648 end:
1649         /*
1650          * The caller only expects -ENODATA when there is no data to read, but
1651          * the kernel tracer returns -EAGAIN when there is currently no data
1652          * for a non-finalized stream, and -ENODATA when there is no data for a
1653          * finalized stream. Those can be combined into a -ENODATA return value.
1654          */
1655         switch (ret) {
1656         case 0:
1657                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1658                 break;
1659         case -ENODATA:
1660         case -EAGAIN:
1661                 /*
1662                  * The caller only expects -ENODATA when there is no data to
1663                  * read, but the kernel tracer returns -EAGAIN when there is
1664                  * currently no data for a non-finalized stream, and -ENODATA
1665                  * when there is no data for a finalized stream. Those can be
1666                  * combined into a -ENODATA return value.
1667                  */
1668                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1669                 break;
1670         default:
1671                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1672                 break;
1673         }
1674
1675         return status;
1676 }
1677
1678 static int put_next_subbuffer(struct lttng_consumer_stream *stream,
1679                               struct stream_subbuffer *subbuffer __attribute__((unused)))
1680 {
1681         const int ret = kernctl_put_next_subbuf(stream->wait_fd);
1682
1683         if (ret) {
1684                 if (ret == -EFAULT) {
1685                         PERROR("Error in unreserving sub buffer");
1686                 } else if (ret == -EIO) {
1687                         /* Should never happen with newer LTTng versions */
1688                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted");
1689                 }
1690         }
1691
1692         return ret;
1693 }
1694
1695 static bool is_get_next_check_metadata_available(int tracer_fd)
1696 {
1697         const int ret = kernctl_get_next_subbuf_metadata_check(tracer_fd, nullptr);
1698         const bool available = ret != -ENOTTY;
1699
1700         if (ret == 0) {
1701                 /* get succeeded, make sure to put the subbuffer. */
1702                 kernctl_put_subbuf(tracer_fd);
1703         }
1704
1705         return available;
1706 }
1707
1708 static int signal_metadata(struct lttng_consumer_stream *stream,
1709                            struct lttng_consumer_local_data *ctx __attribute__((unused)))
1710 {
1711         ASSERT_LOCKED(stream->metadata_rdv_lock);
1712         return pthread_cond_broadcast(&stream->metadata_rdv) ? -errno : 0;
1713 }
1714
1715 static int lttng_kconsumer_set_stream_ops(struct lttng_consumer_stream *stream)
1716 {
1717         int ret = 0;
1718
1719         if (stream->metadata_flag && stream->chan->is_live) {
1720                 DBG("Attempting to enable metadata bucketization for live consumers");
1721                 if (is_get_next_check_metadata_available(stream->wait_fd)) {
1722                         DBG("Kernel tracer supports get_next_subbuffer_metadata_check, metadata will be accumulated until a coherent state is reached");
1723                         stream->read_subbuffer_ops.get_next_subbuffer =
1724                                 get_next_subbuffer_metadata_check;
1725                         ret = consumer_stream_enable_metadata_bucketization(stream);
1726                         if (ret) {
1727                                 goto end;
1728                         }
1729                 } else {
1730                         /*
1731                          * The kernel tracer version is too old to indicate
1732                          * when the metadata stream has reached a "coherent"
1733                          * (parseable) point.
1734                          *
1735                          * This means that a live viewer may see an incoherent
1736                          * sequence of metadata and fail to parse it.
1737                          */
1738                         WARN("Kernel tracer does not support get_next_subbuffer_metadata_check which may cause live clients to fail to parse the metadata stream");
1739                         metadata_bucket_destroy(stream->metadata_bucket);
1740                         stream->metadata_bucket = nullptr;
1741                 }
1742
1743                 stream->read_subbuffer_ops.on_sleep = signal_metadata;
1744         }
1745
1746         if (!stream->read_subbuffer_ops.get_next_subbuffer) {
1747                 if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
1748                         stream->read_subbuffer_ops.get_next_subbuffer = get_next_subbuffer_mmap;
1749                 } else {
1750                         stream->read_subbuffer_ops.get_next_subbuffer = get_next_subbuffer_splice;
1751                 }
1752         }
1753
1754         if (stream->metadata_flag) {
1755                 stream->read_subbuffer_ops.extract_subbuffer_info = extract_metadata_subbuffer_info;
1756         } else {
1757                 stream->read_subbuffer_ops.extract_subbuffer_info = extract_data_subbuffer_info;
1758                 if (stream->chan->is_live) {
1759                         stream->read_subbuffer_ops.send_live_beacon = consumer_flush_kernel_index;
1760                 }
1761         }
1762
1763         stream->read_subbuffer_ops.put_next_subbuffer = put_next_subbuffer;
1764 end:
1765         return ret;
1766 }
1767
1768 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1769 {
1770         int ret;
1771
1772         LTTNG_ASSERT(stream);
1773
1774         /*
1775          * Don't create anything if this is set for streaming or if there is
1776          * no current trace chunk on the parent channel.
1777          */
1778         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor &&
1779             stream->chan->trace_chunk) {
1780                 ret = consumer_stream_create_output_files(stream, true);
1781                 if (ret) {
1782                         goto error;
1783                 }
1784         }
1785
1786         if (stream->output == LTTNG_EVENT_MMAP) {
1787                 /* get the len of the mmap region */
1788                 unsigned long mmap_len;
1789
1790                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1791                 if (ret != 0) {
1792                         PERROR("kernctl_get_mmap_len");
1793                         goto error_close_fd;
1794                 }
1795                 stream->mmap_len = (size_t) mmap_len;
1796
1797                 stream->mmap_base =
1798                         mmap(nullptr, stream->mmap_len, PROT_READ, MAP_PRIVATE, stream->wait_fd, 0);
1799                 if (stream->mmap_base == MAP_FAILED) {
1800                         PERROR("Error mmaping");
1801                         ret = -1;
1802                         goto error_close_fd;
1803                 }
1804         }
1805
1806         ret = lttng_kconsumer_set_stream_ops(stream);
1807         if (ret) {
1808                 goto error_close_fd;
1809         }
1810
1811         /* we return 0 to let the library handle the FD internally */
1812         return 0;
1813
1814 error_close_fd:
1815         if (stream->out_fd >= 0) {
1816                 int err;
1817
1818                 err = close(stream->out_fd);
1819                 LTTNG_ASSERT(!err);
1820                 stream->out_fd = -1;
1821         }
1822 error:
1823         return ret;
1824 }
1825
1826 /*
1827  * Check if data is still being extracted from the buffers for a specific
1828  * stream. Consumer data lock MUST be acquired before calling this function
1829  * and the stream lock.
1830  *
1831  * Return 1 if the traced data are still getting read else 0 meaning that the
1832  * data is available for trace viewer reading.
1833  */
1834 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1835 {
1836         int ret;
1837
1838         LTTNG_ASSERT(stream);
1839
1840         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1841                 ret = 0;
1842                 goto end;
1843         }
1844
1845         ret = kernctl_get_next_subbuf(stream->wait_fd);
1846         if (ret == 0) {
1847                 /* There is still data so let's put back this subbuffer. */
1848                 ret = kernctl_put_subbuf(stream->wait_fd);
1849                 LTTNG_ASSERT(ret == 0);
1850                 ret = 1; /* Data is pending */
1851                 goto end;
1852         }
1853
1854         /* Data is NOT pending and ready to be read. */
1855         ret = 0;
1856
1857 end:
1858         return ret;
1859 }