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/consumer/consumer-stream.hpp>
  17 #include <common/consumer/consumer-timer.hpp>
  18 #include <common/consumer/consumer.hpp>
  19 #include <common/consumer/metadata-bucket.hpp>
  20 #include <common/index/index.hpp>
  21 #include <common/kernel-ctl/kernel-ctl.hpp>
  22 #include <common/optional.hpp>
  23 #include <common/pipe.hpp>
  24 #include <common/relayd/relayd.hpp>
  25 #include <common/sessiond-comm/relayd.hpp>
  26 #include <common/sessiond-comm/sessiond-comm.hpp>
  27 #include <common/urcu.hpp>
  28 #include <common/utils.hpp>
  29
  30 #include <bin/lttng-consumerd/health-consumerd.hpp>
  31 #include <fcntl.h>
  32 #include <inttypes.h>
  33 #include <poll.h>
  34 #include <pthread.h>
  35 #include <stdint.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <sys/mman.h>
  39 #include <sys/socket.h>
  40 #include <sys/stat.h>
  41 #include <sys/types.h>
  42 #include <unistd.h>
  43
  44 extern struct lttng_consumer_global_data the_consumer_data;
  45 extern int consumer_poll_timeout;
  46
  47 /*
  48  * Take a snapshot for a specific fd
  49  *
  50  * Returns 0 on success, < 0 on error
  51  */
  52 int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream *stream)
  53 {
  54         int ret = 0;
  55         int infd = stream->wait_fd;
  56
  57         ret = kernctl_snapshot(infd);
  58         /*
  59          * -EAGAIN is not an error, it just means that there is no data to
  60          *  be read.
  61          */
  62         if (ret != 0 && ret != -EAGAIN) {
  63                 PERROR("Getting sub-buffer snapshot.");
  64         }
  65
  66         return ret;
  67 }
  68
  69 /*
  70  * Sample consumed and produced positions for a specific fd.
  71  *
  72  * Returns 0 on success, < 0 on error.
  73  */
  74 int lttng_kconsumer_sample_snapshot_positions(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, unsigned long *pos)
  87 {
  88         int ret;
  89         int infd = stream->wait_fd;
  90
  91         ret = kernctl_snapshot_get_produced(infd, pos);
  92         if (ret != 0) {
  93                 PERROR("kernctl_snapshot_get_produced");
  94         }
  95
  96         return ret;
  97 }
  98
  99 /*
 100  * Get the consumerd position
 101  *
 102  * Returns 0 on success, < 0 on error
 103  */
 104 int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream *stream, unsigned long *pos)
 105 {
 106         int ret;
 107         int infd = stream->wait_fd;
 108
 109         ret = kernctl_snapshot_get_consumed(infd, pos);
 110         if (ret != 0) {
 111                 PERROR("kernctl_snapshot_get_consumed");
 112         }
 113
 114         return ret;
 115 }
 116
 117 static int get_current_subbuf_addr(struct lttng_consumer_stream *stream, const char **addr)
 118 {
 119         int ret;
 120         unsigned long mmap_offset;
 121         const char *mmap_base = (const char *) stream->mmap_base;
 122
 123         ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
 124         if (ret < 0) {
 125                 PERROR("Failed to get mmap read offset");
 126                 goto error;
 127         }
 128
 129         *addr = mmap_base + mmap_offset;
 130 error:
 131         return ret;
 132 }
 133
 134 /*
 135  * Take a snapshot of all the stream of a channel
 136  * RCU read-side lock must be held across this function to ensure existence of
 137  * channel.
 138  *
 139  * Returns 0 on success, < 0 on error
 140  */
 141 static int lttng_kconsumer_snapshot_channel(struct lttng_consumer_channel *channel,
 142                                             uint64_t key,
 143                                             char *path,
 144                                             uint64_t relayd_id,
 145                                             uint64_t nb_packets_per_stream)
 146 {
 147         int ret;
 148         struct lttng_consumer_stream *stream;
 149
 150         DBG("Kernel consumer snapshot channel %" PRIu64, key);
 151
 152         /* Prevent channel modifications while we perform the snapshot.*/
 153         pthread_mutex_lock(&channel->lock);
 154
 155         lttng::urcu::read_lock_guard read_lock;
 156
 157         /* Splice is not supported yet for channel snapshot. */
 158         if (channel->output != CONSUMER_CHANNEL_MMAP) {
 159                 ERR("Unsupported output type for channel \"%s\": mmap output is required to record a snapshot",
 160                     channel->name);
 161                 ret = -1;
 162                 goto end;
 163         }
 164
 165         cds_list_for_each_entry (stream, &channel->streams.head, send_node) {
 166                 unsigned long consumed_pos, produced_pos;
 167
 168                 health_code_update();
 169
 170                 /*
 171                  * Lock stream because we are about to change its state.
 172                  */
 173                 pthread_mutex_lock(&stream->lock);
 174
 175                 LTTNG_ASSERT(channel->trace_chunk);
 176                 if (!lttng_trace_chunk_get(channel->trace_chunk)) {
 177                         /*
 178                          * Can't happen barring an internal error as the channel
 179                          * holds a reference to the trace chunk.
 180                          */
 181                         ERR("Failed to acquire reference to channel's trace chunk");
 182                         ret = -1;
 183                         goto end_unlock;
 184                 }
 185                 LTTNG_ASSERT(!stream->trace_chunk);
 186                 stream->trace_chunk = channel->trace_chunk;
 187
 188                 /*
 189                  * Assign the received relayd ID so we can use it for streaming. The streams
 190                  * are not visible to anyone so this is OK to change it.
 191                  */
 192                 stream->net_seq_idx = relayd_id;
 193                 channel->relayd_id = relayd_id;
 194                 if (relayd_id != (uint64_t) -1ULL) {
 195                         ret = consumer_send_relayd_stream(stream, path);
 196                         if (ret < 0) {
 197                                 ERR("sending stream to relayd");
 198                                 goto error_close_stream_output;
 199                         }
 200                 } else {
 201                         ret = consumer_stream_create_output_files(stream, false);
 202                         if (ret < 0) {
 203                                 goto error_close_stream_output;
 204                         }
 205                         DBG("Kernel consumer snapshot stream (%" PRIu64 ")", stream->key);
 206                 }
 207
 208                 ret = kernctl_buffer_flush_empty(stream->wait_fd);
 209                 if (ret < 0) {
 210                         /*
 211                          * Doing a buffer flush which does not take into
 212                          * account empty packets. This is not perfect
 213                          * for stream intersection, but required as a
 214                          * fall-back when "flush_empty" is not
 215                          * implemented by lttng-modules.
 216                          */
 217                         ret = kernctl_buffer_flush(stream->wait_fd);
 218                         if (ret < 0) {
 219                                 ERR("Failed to flush kernel stream");
 220                                 goto error_close_stream_output;
 221                         }
 222                         goto end_unlock;
 223                 }
 224
 225                 ret = lttng_kconsumer_take_snapshot(stream);
 226                 if (ret < 0) {
 227                         ERR("Taking kernel snapshot");
 228                         goto error_close_stream_output;
 229                 }
 230
 231                 ret = lttng_kconsumer_get_produced_snapshot(stream, &produced_pos);
 232                 if (ret < 0) {
 233                         ERR("Produced kernel snapshot position");
 234                         goto error_close_stream_output;
 235                 }
 236
 237                 ret = lttng_kconsumer_get_consumed_snapshot(stream, &consumed_pos);
 238                 if (ret < 0) {
 239                         ERR("Consumerd kernel snapshot position");
 240                         goto error_close_stream_output;
 241                 }
 242
 243                 consumed_pos = consumer_get_consume_start_pos(
 244                         consumed_pos, produced_pos, nb_packets_per_stream, stream->max_sb_size);
 245
 246                 while ((long) (consumed_pos - produced_pos) < 0) {
 247                         ssize_t read_len;
 248                         unsigned long len, padded_len;
 249                         const char *subbuf_addr;
 250                         struct lttng_buffer_view subbuf_view;
 251
 252                         health_code_update();
 253                         DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 254
 255                         ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
 256                         if (ret < 0) {
 257                                 if (ret != -EAGAIN) {
 258                                         PERROR("kernctl_get_subbuf snapshot");
 259                                         goto error_close_stream_output;
 260                                 }
 261                                 DBG("Kernel consumer get subbuf failed. Skipping it.");
 262                                 consumed_pos += stream->max_sb_size;
 263                                 stream->chan->lost_packets++;
 264                                 continue;
 265                         }
 266
 267                         ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
 268                         if (ret < 0) {
 269                                 ERR("Snapshot kernctl_get_subbuf_size");
 270                                 goto error_put_subbuf;
 271                         }
 272
 273                         ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
 274                         if (ret < 0) {
 275                                 ERR("Snapshot kernctl_get_padded_subbuf_size");
 276                                 goto error_put_subbuf;
 277                         }
 278
 279                         ret = get_current_subbuf_addr(stream, &subbuf_addr);
 280                         if (ret) {
 281                                 goto error_put_subbuf;
 282                         }
 283
 284                         subbuf_view = lttng_buffer_view_init(subbuf_addr, 0, padded_len);
 285                         read_len = lttng_consumer_on_read_subbuffer_mmap(
 286                                 stream, &subbuf_view, padded_len - len);
 287                         /*
 288                          * We write the padded len in local tracefiles but the data len
 289                          * when using a relay. Display the error but continue processing
 290                          * to try to release the subbuffer.
 291                          */
 292                         if (relayd_id != (uint64_t) -1ULL) {
 293                                 if (read_len != len) {
 294                                         ERR("Error sending to the relay (ret: %zd != len: %lu)",
 295                                             read_len,
 296                                             len);
 297                                 }
 298                         } else {
 299                                 if (read_len != padded_len) {
 300                                         ERR("Error writing to tracefile (ret: %zd != len: %lu)",
 301                                             read_len,
 302                                             padded_len);
 303                                 }
 304                         }
 305
 306                         ret = kernctl_put_subbuf(stream->wait_fd);
 307                         if (ret < 0) {
 308                                 ERR("Snapshot kernctl_put_subbuf");
 309                                 goto error_close_stream_output;
 310                         }
 311                         consumed_pos += stream->max_sb_size;
 312                 }
 313
 314                 consumer_stream_close_output(stream);
 315                 pthread_mutex_unlock(&stream->lock);
 316         }
 317
 318         /* All good! */
 319         ret = 0;
 320         goto end;
 321
 322 error_put_subbuf:
 323         ret = kernctl_put_subbuf(stream->wait_fd);
 324         if (ret < 0) {
 325                 ERR("Snapshot kernctl_put_subbuf error path");
 326         }
 327 error_close_stream_output:
 328         consumer_stream_close_output(stream);
 329 end_unlock:
 330         pthread_mutex_unlock(&stream->lock);
 331 end:
 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         lttng::urcu::read_lock_guard 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         return ret;
 419 }
 420
 421 /*
 422  * Receive command from session daemon and process it.
 423  *
 424  * Return 1 on success else a negative value or 0.
 425  */
 426 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 427                              int sock,
 428                              struct pollfd *consumer_sockpoll)
 429 {
 430         int ret_func;
 431         enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 432         struct lttcomm_consumer_msg msg;
 433
 434         health_code_update();
 435
 436         {
 437                 ssize_t ret_recv;
 438
 439                 ret_recv = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 440                 if (ret_recv != sizeof(msg)) {
 441                         if (ret_recv > 0) {
 442                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 443                                 ret_recv = -1;
 444                         }
 445                         return ret_recv;
 446                 }
 447         }
 448
 449         health_code_update();
 450
 451         /* Deprecated command */
 452         LTTNG_ASSERT(msg.cmd_type != LTTNG_CONSUMER_STOP);
 453
 454         health_code_update();
 455
 456         /* relayd needs RCU read-side protection */
 457         lttng::urcu::read_lock_guard read_lock;
 458
 459         switch (msg.cmd_type) {
 460         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 461         {
 462                 uint32_t major = msg.u.relayd_sock.major;
 463                 uint32_t minor = msg.u.relayd_sock.minor;
 464                 enum lttcomm_sock_proto protocol =
 465                         (enum lttcomm_sock_proto) msg.u.relayd_sock.relayd_socket_protocol;
 466
 467                 /* Session daemon status message are handled in the following call. */
 468                 consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 469                                            msg.u.relayd_sock.type,
 470                                            ctx,
 471                                            sock,
 472                                            consumer_sockpoll,
 473                                            msg.u.relayd_sock.session_id,
 474                                            msg.u.relayd_sock.relayd_session_id,
 475                                            major,
 476                                            minor,
 477                                            protocol);
 478                 goto end_nosignal;
 479         }
 480         case LTTNG_CONSUMER_ADD_CHANNEL:
 481         {
 482                 struct lttng_consumer_channel *new_channel;
 483                 int ret_send_status, ret_add_channel = 0;
 484                 const uint64_t chunk_id = msg.u.channel.chunk_id.value;
 485
 486                 health_code_update();
 487
 488                 /* First send a status message before receiving the fds. */
 489                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 490                 if (ret_send_status < 0) {
 491                         /* Somehow, the session daemon is not responding anymore. */
 492                         goto error_fatal;
 493                 }
 494
 495                 health_code_update();
 496
 497                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 498                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 499                                                         msg.u.channel.session_id,
 500                                                         msg.u.channel.chunk_id.is_set ? &chunk_id :
 501                                                                                         nullptr,
 502                                                         msg.u.channel.pathname,
 503                                                         msg.u.channel.name,
 504                                                         msg.u.channel.relayd_id,
 505                                                         msg.u.channel.output,
 506                                                         msg.u.channel.tracefile_size,
 507                                                         msg.u.channel.tracefile_count,
 508                                                         0,
 509                                                         msg.u.channel.monitor,
 510                                                         msg.u.channel.live_timer_interval,
 511                                                         msg.u.channel.is_live,
 512                                                         nullptr,
 513                                                         nullptr);
 514                 if (new_channel == nullptr) {
 515                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 516                         goto end_nosignal;
 517                 }
 518                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 519                 switch (msg.u.channel.output) {
 520                 case LTTNG_EVENT_SPLICE:
 521                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 522                         break;
 523                 case LTTNG_EVENT_MMAP:
 524                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 525                         break;
 526                 default:
 527                         ERR("Channel output unknown %d", msg.u.channel.output);
 528                         goto end_nosignal;
 529                 }
 530
 531                 /* Translate and save channel type. */
 532                 switch (msg.u.channel.type) {
 533                 case CONSUMER_CHANNEL_TYPE_DATA:
 534                 case CONSUMER_CHANNEL_TYPE_METADATA:
 535                         new_channel->type = (consumer_channel_type) msg.u.channel.type;
 536                         break;
 537                 default:
 538                         abort();
 539                         goto end_nosignal;
 540                 };
 541
 542                 health_code_update();
 543
 544                 if (ctx->on_recv_channel != nullptr) {
 545                         int ret_recv_channel = ctx->on_recv_channel(new_channel);
 546                         if (ret_recv_channel == 0) {
 547                                 ret_add_channel = consumer_add_channel(new_channel, ctx);
 548                         } else if (ret_recv_channel < 0) {
 549                                 goto end_nosignal;
 550                         }
 551                 } else {
 552                         ret_add_channel = consumer_add_channel(new_channel, ctx);
 553                 }
 554                 if (msg.u.channel.type == CONSUMER_CHANNEL_TYPE_DATA && !ret_add_channel) {
 555                         int monitor_start_ret;
 556
 557                         DBG("Consumer starting monitor timer");
 558                         consumer_timer_live_start(new_channel, msg.u.channel.live_timer_interval);
 559                         monitor_start_ret = consumer_timer_monitor_start(
 560                                 new_channel, msg.u.channel.monitor_timer_interval);
 561                         if (monitor_start_ret < 0) {
 562                                 ERR("Starting channel monitoring timer failed");
 563                                 goto end_nosignal;
 564                         }
 565                 }
 566
 567                 health_code_update();
 568
 569                 /* If we received an error in add_channel, we need to report it. */
 570                 if (ret_add_channel < 0) {
 571                         ret_send_status = consumer_send_status_msg(sock, ret_add_channel);
 572                         if (ret_send_status < 0) {
 573                                 goto error_fatal;
 574                         }
 575                         goto end_nosignal;
 576                 }
 577
 578                 goto end_nosignal;
 579         }
 580         case LTTNG_CONSUMER_ADD_STREAM:
 581         {
 582                 int fd;
 583                 struct lttng_pipe *stream_pipe;
 584                 struct lttng_consumer_stream *new_stream;
 585                 struct lttng_consumer_channel *channel;
 586                 int alloc_ret = 0;
 587                 int ret_send_status, ret_poll, ret_get_max_subbuf_size;
 588                 ssize_t ret_pipe_write, ret_recv;
 589
 590                 /*
 591                  * Get stream's channel reference. Needed when adding the stream to the
 592                  * global hash table.
 593                  */
 594                 channel = consumer_find_channel(msg.u.stream.channel_key);
 595                 if (!channel) {
 596                         /*
 597                          * We could not find the channel. Can happen if cpu hotplug
 598                          * happens while tearing down.
 599                          */
 600                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 601                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 602                 }
 603
 604                 health_code_update();
 605
 606                 /* First send a status message before receiving the fds. */
 607                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 608                 if (ret_send_status < 0) {
 609                         /* Somehow, the session daemon is not responding anymore. */
 610                         goto error_add_stream_fatal;
 611                 }
 612
 613                 health_code_update();
 614
 615                 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 616                         /* Channel was not found. */
 617                         goto error_add_stream_nosignal;
 618                 }
 619
 620                 /* Blocking call */
 621                 health_poll_entry();
 622                 ret_poll = lttng_consumer_poll_socket(consumer_sockpoll);
 623                 health_poll_exit();
 624                 if (ret_poll) {
 625                         goto error_add_stream_fatal;
 626                 }
 627
 628                 health_code_update();
 629
 630                 /* Get stream file descriptor from socket */
 631                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 632                 if (ret_recv != sizeof(fd)) {
 633                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 634                         ret_func = ret_recv;
 635                         goto end;
 636                 }
 637
 638                 health_code_update();
 639
 640                 /*
 641                  * Send status code to session daemon only if the recv works. If the
 642                  * above recv() failed, the session daemon is notified through the
 643                  * error socket and the teardown is eventually done.
 644                  */
 645                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 646                 if (ret_send_status < 0) {
 647                         /* Somehow, the session daemon is not responding anymore. */
 648                         goto error_add_stream_nosignal;
 649                 }
 650
 651                 health_code_update();
 652
 653                 pthread_mutex_lock(&channel->lock);
 654                 new_stream = consumer_stream_create(channel,
 655                                                     channel->key,
 656                                                     fd,
 657                                                     channel->name,
 658                                                     channel->relayd_id,
 659                                                     channel->session_id,
 660                                                     channel->trace_chunk,
 661                                                     msg.u.stream.cpu,
 662                                                     &alloc_ret,
 663                                                     channel->type,
 664                                                     channel->monitor);
 665                 if (new_stream == nullptr) {
 666                         switch (alloc_ret) {
 667                         case -ENOMEM:
 668                         case -EINVAL:
 669                         default:
 670                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 671                                 break;
 672                         }
 673                         pthread_mutex_unlock(&channel->lock);
 674                         goto error_add_stream_nosignal;
 675                 }
 676
 677                 new_stream->wait_fd = fd;
 678                 ret_get_max_subbuf_size =
 679                         kernctl_get_max_subbuf_size(new_stream->wait_fd, &new_stream->max_sb_size);
 680                 if (ret_get_max_subbuf_size < 0) {
 681                         pthread_mutex_unlock(&channel->lock);
 682                         ERR("Failed to get kernel maximal subbuffer size");
 683                         goto error_add_stream_nosignal;
 684                 }
 685
 686                 consumer_stream_update_channel_attributes(new_stream, channel);
 687
 688                 /*
 689                  * We've just assigned the channel to the stream so increment the
 690                  * refcount right now. We don't need to increment the refcount for
 691                  * streams in no monitor because we handle manually the cleanup of
 692                  * those. It is very important to make sure there is NO prior
 693                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 694                  */
 695                 if (channel->monitor) {
 696                         uatomic_inc(&new_stream->chan->refcount);
 697                 }
 698
 699                 /*
 700                  * The buffer flush is done on the session daemon side for the kernel
 701                  * so no need for the stream "hangup_flush_done" variable to be
 702                  * tracked. This is important for a kernel stream since we don't rely
 703                  * on the flush state of the stream to read data. It's not the case for
 704                  * user space tracing.
 705                  */
 706                 new_stream->hangup_flush_done = 0;
 707
 708                 health_code_update();
 709
 710                 pthread_mutex_lock(&new_stream->lock);
 711                 if (ctx->on_recv_stream) {
 712                         int ret_recv_stream = ctx->on_recv_stream(new_stream);
 713                         if (ret_recv_stream < 0) {
 714                                 pthread_mutex_unlock(&new_stream->lock);
 715                                 pthread_mutex_unlock(&channel->lock);
 716                                 consumer_stream_free(new_stream);
 717                                 goto error_add_stream_nosignal;
 718                         }
 719                 }
 720                 health_code_update();
 721
 722                 if (new_stream->metadata_flag) {
 723                         channel->metadata_stream = new_stream;
 724                 }
 725
 726                 /* Do not monitor this stream. */
 727                 if (!channel->monitor) {
 728                         DBG("Kernel consumer add stream %s in no monitor mode with "
 729                             "relayd id %" PRIu64,
 730                             new_stream->name,
 731                             new_stream->net_seq_idx);
 732                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 733                         pthread_mutex_unlock(&new_stream->lock);
 734                         pthread_mutex_unlock(&channel->lock);
 735                         goto end_add_stream;
 736                 }
 737
 738                 /* Send stream to relayd if the stream has an ID. */
 739                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 740                         int ret_send_relayd_stream;
 741
 742                         ret_send_relayd_stream =
 743                                 consumer_send_relayd_stream(new_stream, new_stream->chan->pathname);
 744                         if (ret_send_relayd_stream < 0) {
 745                                 pthread_mutex_unlock(&new_stream->lock);
 746                                 pthread_mutex_unlock(&channel->lock);
 747                                 consumer_stream_free(new_stream);
 748                                 goto error_add_stream_nosignal;
 749                         }
 750
 751                         /*
 752                          * If adding an extra stream to an already
 753                          * existing channel (e.g. cpu hotplug), we need
 754                          * to send the "streams_sent" command to relayd.
 755                          */
 756                         if (channel->streams_sent_to_relayd) {
 757                                 int ret_send_relayd_streams_sent;
 758
 759                                 ret_send_relayd_streams_sent =
 760                                         consumer_send_relayd_streams_sent(new_stream->net_seq_idx);
 761                                 if (ret_send_relayd_streams_sent < 0) {
 762                                         pthread_mutex_unlock(&new_stream->lock);
 763                                         pthread_mutex_unlock(&channel->lock);
 764                                         goto error_add_stream_nosignal;
 765                                 }
 766                         }
 767                 }
 768                 pthread_mutex_unlock(&new_stream->lock);
 769                 pthread_mutex_unlock(&channel->lock);
 770
 771                 /* Get the right pipe where the stream will be sent. */
 772                 if (new_stream->metadata_flag) {
 773                         consumer_add_metadata_stream(new_stream);
 774                         stream_pipe = ctx->consumer_metadata_pipe;
 775                 } else {
 776                         consumer_add_data_stream(new_stream);
 777                         stream_pipe = ctx->consumer_data_pipe;
 778                 }
 779
 780                 /* Visible to other threads */
 781                 new_stream->globally_visible = 1;
 782
 783                 health_code_update();
 784
 785                 ret_pipe_write =
 786                         lttng_pipe_write(stream_pipe, &new_stream, sizeof(new_stream)); /* NOLINT
 787                                                                                            sizeof
 788                                                                                            used on a
 789                                                                                            pointer.
 790                                                                                          */
 791                 if (ret_pipe_write < 0) {
 792                         ERR("Consumer write %s stream to pipe %d",
 793                             new_stream->metadata_flag ? "metadata" : "data",
 794                             lttng_pipe_get_writefd(stream_pipe));
 795                         if (new_stream->metadata_flag) {
 796                                 consumer_del_stream_for_metadata(new_stream);
 797                         } else {
 798                                 consumer_del_stream_for_data(new_stream);
 799                         }
 800                         goto error_add_stream_nosignal;
 801                 }
 802
 803                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
 804                     new_stream->name,
 805                     fd,
 806                     new_stream->chan->pathname,
 807                     new_stream->relayd_stream_id);
 808         end_add_stream:
 809                 break;
 810         error_add_stream_nosignal:
 811                 goto end_nosignal;
 812         error_add_stream_fatal:
 813                 goto error_fatal;
 814         }
 815         case LTTNG_CONSUMER_STREAMS_SENT:
 816         {
 817                 struct lttng_consumer_channel *channel;
 818                 int ret_send_status;
 819
 820                 /*
 821                  * Get stream's channel reference. Needed when adding the stream to the
 822                  * global hash table.
 823                  */
 824                 channel = consumer_find_channel(msg.u.sent_streams.channel_key);
 825                 if (!channel) {
 826                         /*
 827                          * We could not find the channel. Can happen if cpu hotplug
 828                          * happens while tearing down.
 829                          */
 830                         ERR("Unable to find channel key %" PRIu64, msg.u.sent_streams.channel_key);
 831                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 832                 }
 833
 834                 health_code_update();
 835
 836                 /*
 837                  * Send status code to session daemon.
 838                  */
 839                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 840                 if (ret_send_status < 0 || ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 841                         /* Somehow, the session daemon is not responding anymore. */
 842                         goto error_streams_sent_nosignal;
 843                 }
 844
 845                 health_code_update();
 846
 847                 /*
 848                  * We should not send this message if we don't monitor the
 849                  * streams in this channel.
 850                  */
 851                 if (!channel->monitor) {
 852                         goto end_error_streams_sent;
 853                 }
 854
 855                 health_code_update();
 856                 /* Send stream to relayd if the stream has an ID. */
 857                 if (msg.u.sent_streams.net_seq_idx != (uint64_t) -1ULL) {
 858                         int ret_send_relay_streams;
 859
 860                         ret_send_relay_streams =
 861                                 consumer_send_relayd_streams_sent(msg.u.sent_streams.net_seq_idx);
 862                         if (ret_send_relay_streams < 0) {
 863                                 goto error_streams_sent_nosignal;
 864                         }
 865                         channel->streams_sent_to_relayd = true;
 866                 }
 867         end_error_streams_sent:
 868                 break;
 869         error_streams_sent_nosignal:
 870                 goto end_nosignal;
 871         }
 872         case LTTNG_CONSUMER_UPDATE_STREAM:
 873         {
 874                 return -ENOSYS;
 875         }
 876         case LTTNG_CONSUMER_DESTROY_RELAYD:
 877         {
 878                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 879                 struct consumer_relayd_sock_pair *relayd;
 880                 int ret_send_status;
 881
 882                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 883
 884                 /* Get relayd reference if exists. */
 885                 relayd = consumer_find_relayd(index);
 886                 if (relayd == nullptr) {
 887                         DBG("Unable to find relayd %" PRIu64, index);
 888                         ret_code = LTTCOMM_CONSUMERD_RELAYD_FAIL;
 889                 }
 890
 891                 /*
 892                  * Each relayd socket pair has a refcount of stream attached to it
 893                  * which tells if the relayd is still active or not depending on the
 894                  * refcount value.
 895                  *
 896                  * This will set the destroy flag of the relayd object and destroy it
 897                  * if the refcount reaches zero when called.
 898                  *
 899                  * The destroy can happen either here or when a stream fd hangs up.
 900                  */
 901                 if (relayd) {
 902                         consumer_flag_relayd_for_destroy(relayd);
 903                 }
 904
 905                 health_code_update();
 906
 907                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 908                 if (ret_send_status < 0) {
 909                         /* Somehow, the session daemon is not responding anymore. */
 910                         goto error_fatal;
 911                 }
 912
 913                 goto end_nosignal;
 914         }
 915         case LTTNG_CONSUMER_DATA_PENDING:
 916         {
 917                 int32_t ret_data_pending;
 918                 uint64_t id = msg.u.data_pending.session_id;
 919                 ssize_t ret_send;
 920
 921                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 922
 923                 ret_data_pending = consumer_data_pending(id);
 924
 925                 health_code_update();
 926
 927                 /* Send back returned value to session daemon */
 928                 ret_send =
 929                         lttcomm_send_unix_sock(sock, &ret_data_pending, sizeof(ret_data_pending));
 930                 if (ret_send < 0) {
 931                         PERROR("send data pending ret code");
 932                         goto error_fatal;
 933                 }
 934
 935                 /*
 936                  * No need to send back a status message since the data pending
 937                  * returned value is the response.
 938                  */
 939                 break;
 940         }
 941         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 942         {
 943                 struct lttng_consumer_channel *channel;
 944                 uint64_t key = msg.u.snapshot_channel.key;
 945                 int ret_send_status;
 946
 947                 channel = consumer_find_channel(key);
 948                 if (!channel) {
 949                         ERR("Channel %" PRIu64 " not found", key);
 950                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 951                 } else {
 952                         if (msg.u.snapshot_channel.metadata == 1) {
 953                                 int ret_snapshot;
 954
 955                                 ret_snapshot = lttng_kconsumer_snapshot_metadata(
 956                                         channel,
 957                                         key,
 958                                         msg.u.snapshot_channel.pathname,
 959                                         msg.u.snapshot_channel.relayd_id,
 960                                         ctx);
 961                                 if (ret_snapshot < 0) {
 962                                         ERR("Snapshot metadata failed");
 963                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 964                                 }
 965                         } else {
 966                                 int ret_snapshot;
 967
 968                                 ret_snapshot = lttng_kconsumer_snapshot_channel(
 969                                         channel,
 970                                         key,
 971                                         msg.u.snapshot_channel.pathname,
 972                                         msg.u.snapshot_channel.relayd_id,
 973                                         msg.u.snapshot_channel.nb_packets_per_stream);
 974                                 if (ret_snapshot < 0) {
 975                                         ERR("Snapshot channel failed");
 976                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 977                                 }
 978                         }
 979                 }
 980                 health_code_update();
 981
 982                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 983                 if (ret_send_status < 0) {
 984                         /* Somehow, the session daemon is not responding anymore. */
 985                         goto end_nosignal;
 986                 }
 987                 break;
 988         }
 989         case LTTNG_CONSUMER_DESTROY_CHANNEL:
 990         {
 991                 uint64_t key = msg.u.destroy_channel.key;
 992                 struct lttng_consumer_channel *channel;
 993                 int ret_send_status;
 994
 995                 channel = consumer_find_channel(key);
 996                 if (!channel) {
 997                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
 998                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 999                 }
1000
1001                 health_code_update();
1002
1003                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1004                 if (ret_send_status < 0) {
1005                         /* Somehow, the session daemon is not responding anymore. */
1006                         goto end_destroy_channel;
1007                 }
1008
1009                 health_code_update();
1010
1011                 /* Stop right now if no channel was found. */
1012                 if (!channel) {
1013                         goto end_destroy_channel;
1014                 }
1015
1016                 /*
1017                  * This command should ONLY be issued for channel with streams set in
1018                  * no monitor mode.
1019                  */
1020                 LTTNG_ASSERT(!channel->monitor);
1021
1022                 /*
1023                  * The refcount should ALWAYS be 0 in the case of a channel in no
1024                  * monitor mode.
1025                  */
1026                 LTTNG_ASSERT(!uatomic_sub_return(&channel->refcount, 1));
1027
1028                 consumer_del_channel(channel);
1029         end_destroy_channel:
1030                 goto end_nosignal;
1031         }
1032         case LTTNG_CONSUMER_DISCARDED_EVENTS:
1033         {
1034                 ssize_t ret;
1035                 uint64_t count;
1036                 struct lttng_consumer_channel *channel;
1037                 uint64_t id = msg.u.discarded_events.session_id;
1038                 uint64_t key = msg.u.discarded_events.channel_key;
1039
1040                 DBG("Kernel consumer discarded events command for session id %" PRIu64
1041                     ", channel key %" PRIu64,
1042                     id,
1043                     key);
1044
1045                 channel = consumer_find_channel(key);
1046                 if (!channel) {
1047                         ERR("Kernel consumer discarded events channel %" PRIu64 " not found", key);
1048                         count = 0;
1049                 } else {
1050                         count = channel->discarded_events;
1051                 }
1052
1053                 health_code_update();
1054
1055                 /* Send back returned value to session daemon */
1056                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1057                 if (ret < 0) {
1058                         PERROR("send discarded events");
1059                         goto error_fatal;
1060                 }
1061
1062                 break;
1063         }
1064         case LTTNG_CONSUMER_LOST_PACKETS:
1065         {
1066                 ssize_t ret;
1067                 uint64_t count;
1068                 struct lttng_consumer_channel *channel;
1069                 uint64_t id = msg.u.lost_packets.session_id;
1070                 uint64_t key = msg.u.lost_packets.channel_key;
1071
1072                 DBG("Kernel consumer lost packets command for session id %" PRIu64
1073                     ", channel key %" PRIu64,
1074                     id,
1075                     key);
1076
1077                 channel = consumer_find_channel(key);
1078                 if (!channel) {
1079                         ERR("Kernel consumer lost packets channel %" PRIu64 " not found", key);
1080                         count = 0;
1081                 } else {
1082                         count = channel->lost_packets;
1083                 }
1084
1085                 health_code_update();
1086
1087                 /* Send back returned value to session daemon */
1088                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1089                 if (ret < 0) {
1090                         PERROR("send lost packets");
1091                         goto error_fatal;
1092                 }
1093
1094                 break;
1095         }
1096         case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
1097         {
1098                 int channel_monitor_pipe;
1099                 int ret_send_status, ret_set_channel_monitor_pipe;
1100                 ssize_t ret_recv;
1101
1102                 ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1103                 /* Successfully received the command's type. */
1104                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1105                 if (ret_send_status < 0) {
1106                         goto error_fatal;
1107                 }
1108
1109                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &channel_monitor_pipe, 1);
1110                 if (ret_recv != sizeof(channel_monitor_pipe)) {
1111                         ERR("Failed to receive channel monitor pipe");
1112                         goto error_fatal;
1113                 }
1114
1115                 DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
1116                 ret_set_channel_monitor_pipe =
1117                         consumer_timer_thread_set_channel_monitor_pipe(channel_monitor_pipe);
1118                 if (!ret_set_channel_monitor_pipe) {
1119                         int flags;
1120                         int ret_fcntl;
1121
1122                         ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1123                         /* Set the pipe as non-blocking. */
1124                         ret_fcntl = fcntl(channel_monitor_pipe, F_GETFL, 0);
1125                         if (ret_fcntl == -1) {
1126                                 PERROR("fcntl get flags of the channel monitoring pipe");
1127                                 goto error_fatal;
1128                         }
1129                         flags = ret_fcntl;
1130
1131                         ret_fcntl = fcntl(channel_monitor_pipe, F_SETFL, flags | O_NONBLOCK);
1132                         if (ret_fcntl == -1) {
1133                                 PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
1134                                 goto error_fatal;
1135                         }
1136                         DBG("Channel monitor pipe set as non-blocking");
1137                 } else {
1138                         ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
1139                 }
1140                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1141                 if (ret_send_status < 0) {
1142                         goto error_fatal;
1143                 }
1144                 break;
1145         }
1146         case LTTNG_CONSUMER_ROTATE_CHANNEL:
1147         {
1148                 struct lttng_consumer_channel *channel;
1149                 uint64_t key = msg.u.rotate_channel.key;
1150                 int ret_send_status;
1151
1152                 DBG("Consumer rotate channel %" PRIu64, key);
1153
1154                 channel = consumer_find_channel(key);
1155                 if (!channel) {
1156                         ERR("Channel %" PRIu64 " not found", key);
1157                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1158                 } else {
1159                         /*
1160                          * Sample the rotate position of all the streams in this channel.
1161                          */
1162                         int ret_rotate_channel;
1163
1164                         ret_rotate_channel = lttng_consumer_rotate_channel(
1165                                 channel, key, msg.u.rotate_channel.relayd_id);
1166                         if (ret_rotate_channel < 0) {
1167                                 ERR("Rotate channel failed");
1168                                 ret_code = LTTCOMM_CONSUMERD_ROTATION_FAIL;
1169                         }
1170
1171                         health_code_update();
1172                 }
1173
1174                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1175                 if (ret_send_status < 0) {
1176                         /* Somehow, the session daemon is not responding anymore. */
1177                         goto error_rotate_channel;
1178                 }
1179                 if (channel) {
1180                         /* Rotate the streams that are ready right now. */
1181                         int ret_rotate;
1182
1183                         ret_rotate = lttng_consumer_rotate_ready_streams(channel, key);
1184                         if (ret_rotate < 0) {
1185                                 ERR("Rotate ready streams failed");
1186                         }
1187                 }
1188                 break;
1189         error_rotate_channel:
1190                 goto end_nosignal;
1191         }
1192         case LTTNG_CONSUMER_CLEAR_CHANNEL:
1193         {
1194                 struct lttng_consumer_channel *channel;
1195                 uint64_t key = msg.u.clear_channel.key;
1196                 int ret_send_status;
1197
1198                 channel = consumer_find_channel(key);
1199                 if (!channel) {
1200                         DBG("Channel %" PRIu64 " not found", key);
1201                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1202                 } else {
1203                         int ret_clear_channel;
1204
1205                         ret_clear_channel = lttng_consumer_clear_channel(channel);
1206                         if (ret_clear_channel) {
1207                                 ERR("Clear channel failed");
1208                                 ret_code = (lttcomm_return_code) ret_clear_channel;
1209                         }
1210
1211                         health_code_update();
1212                 }
1213
1214                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1215                 if (ret_send_status < 0) {
1216                         /* Somehow, the session daemon is not responding anymore. */
1217                         goto end_nosignal;
1218                 }
1219
1220                 break;
1221         }
1222         case LTTNG_CONSUMER_INIT:
1223         {
1224                 int ret_send_status;
1225                 lttng_uuid sessiond_uuid;
1226
1227                 std::copy(std::begin(msg.u.init.sessiond_uuid),
1228                           std::end(msg.u.init.sessiond_uuid),
1229                           sessiond_uuid.begin());
1230
1231                 ret_code = lttng_consumer_init_command(ctx, sessiond_uuid);
1232                 health_code_update();
1233                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1234                 if (ret_send_status < 0) {
1235                         /* Somehow, the session daemon is not responding anymore. */
1236                         goto end_nosignal;
1237                 }
1238                 break;
1239         }
1240         case LTTNG_CONSUMER_CREATE_TRACE_CHUNK:
1241         {
1242                 const struct lttng_credentials credentials = {
1243                         .uid = LTTNG_OPTIONAL_INIT_VALUE(
1244                                 msg.u.create_trace_chunk.credentials.value.uid),
1245                         .gid = LTTNG_OPTIONAL_INIT_VALUE(
1246                                 msg.u.create_trace_chunk.credentials.value.gid),
1247                 };
1248                 const bool is_local_trace = !msg.u.create_trace_chunk.relayd_id.is_set;
1249                 const uint64_t relayd_id = msg.u.create_trace_chunk.relayd_id.value;
1250                 const char *chunk_override_name = *msg.u.create_trace_chunk.override_name ?
1251                         msg.u.create_trace_chunk.override_name :
1252                         nullptr;
1253                 struct lttng_directory_handle *chunk_directory_handle = nullptr;
1254
1255                 /*
1256                  * The session daemon will only provide a chunk directory file
1257                  * descriptor for local traces.
1258                  */
1259                 if (is_local_trace) {
1260                         int chunk_dirfd;
1261                         int ret_send_status;
1262                         ssize_t ret_recv;
1263
1264                         /* Acnowledge the reception of the command. */
1265                         ret_send_status = consumer_send_status_msg(sock, LTTCOMM_CONSUMERD_SUCCESS);
1266                         if (ret_send_status < 0) {
1267                                 /* Somehow, the session daemon is not responding anymore. */
1268                                 goto end_nosignal;
1269                         }
1270
1271                         ret_recv = lttcomm_recv_fds_unix_sock(sock, &chunk_dirfd, 1);
1272                         if (ret_recv != sizeof(chunk_dirfd)) {
1273                                 ERR("Failed to receive trace chunk directory file descriptor");
1274                                 goto error_fatal;
1275                         }
1276
1277                         DBG("Received trace chunk directory fd (%d)", chunk_dirfd);
1278                         chunk_directory_handle =
1279                                 lttng_directory_handle_create_from_dirfd(chunk_dirfd);
1280                         if (!chunk_directory_handle) {
1281                                 ERR("Failed to initialize chunk directory handle from directory file descriptor");
1282                                 if (close(chunk_dirfd)) {
1283                                         PERROR("Failed to close chunk directory file descriptor");
1284                                 }
1285                                 goto error_fatal;
1286                         }
1287                 }
1288
1289                 ret_code = lttng_consumer_create_trace_chunk(
1290                         !is_local_trace ? &relayd_id : nullptr,
1291                         msg.u.create_trace_chunk.session_id,
1292                         msg.u.create_trace_chunk.chunk_id,
1293                         (time_t) msg.u.create_trace_chunk.creation_timestamp,
1294                         chunk_override_name,
1295                         msg.u.create_trace_chunk.credentials.is_set ? &credentials : nullptr,
1296                         chunk_directory_handle);
1297                 lttng_directory_handle_put(chunk_directory_handle);
1298                 goto end_msg_sessiond;
1299         }
1300         case LTTNG_CONSUMER_CLOSE_TRACE_CHUNK:
1301         {
1302                 enum lttng_trace_chunk_command_type close_command =
1303                         (lttng_trace_chunk_command_type) msg.u.close_trace_chunk.close_command.value;
1304                 const uint64_t relayd_id = msg.u.close_trace_chunk.relayd_id.value;
1305                 struct lttcomm_consumer_close_trace_chunk_reply reply;
1306                 char path[LTTNG_PATH_MAX];
1307                 ssize_t ret_send;
1308
1309                 ret_code = lttng_consumer_close_trace_chunk(
1310                         msg.u.close_trace_chunk.relayd_id.is_set ? &relayd_id : nullptr,
1311                         msg.u.close_trace_chunk.session_id,
1312                         msg.u.close_trace_chunk.chunk_id,
1313                         (time_t) msg.u.close_trace_chunk.close_timestamp,
1314                         msg.u.close_trace_chunk.close_command.is_set ? &close_command : nullptr,
1315                         path);
1316                 reply.ret_code = ret_code;
1317                 reply.path_length = strlen(path) + 1;
1318                 ret_send = lttcomm_send_unix_sock(sock, &reply, sizeof(reply));
1319                 if (ret_send != sizeof(reply)) {
1320                         goto error_fatal;
1321                 }
1322                 ret_send = lttcomm_send_unix_sock(sock, path, reply.path_length);
1323                 if (ret_send != reply.path_length) {
1324                         goto error_fatal;
1325                 }
1326                 goto end_nosignal;
1327         }
1328         case LTTNG_CONSUMER_TRACE_CHUNK_EXISTS:
1329         {
1330                 const uint64_t relayd_id = msg.u.trace_chunk_exists.relayd_id.value;
1331
1332                 ret_code = lttng_consumer_trace_chunk_exists(
1333                         msg.u.trace_chunk_exists.relayd_id.is_set ? &relayd_id : nullptr,
1334                         msg.u.trace_chunk_exists.session_id,
1335                         msg.u.trace_chunk_exists.chunk_id);
1336                 goto end_msg_sessiond;
1337         }
1338         case LTTNG_CONSUMER_OPEN_CHANNEL_PACKETS:
1339         {
1340                 const uint64_t key = msg.u.open_channel_packets.key;
1341                 struct lttng_consumer_channel *channel = consumer_find_channel(key);
1342
1343                 if (channel) {
1344                         pthread_mutex_lock(&channel->lock);
1345                         ret_code = lttng_consumer_open_channel_packets(channel);
1346                         pthread_mutex_unlock(&channel->lock);
1347                 } else {
1348                         WARN("Channel %" PRIu64 " not found", key);
1349                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1350                 }
1351
1352                 health_code_update();
1353                 goto end_msg_sessiond;
1354         }
1355         default:
1356                 goto end_nosignal;
1357         }
1358
1359 end_nosignal:
1360         /*
1361          * Return 1 to indicate success since the 0 value can be a socket
1362          * shutdown during the recv() or send() call.
1363          */
1364         ret_func = 1;
1365         goto end;
1366 error_fatal:
1367         /* This will issue a consumer stop. */
1368         ret_func = -1;
1369         goto end;
1370 end_msg_sessiond:
1371         /*
1372          * The returned value here is not useful since either way we'll return 1 to
1373          * the caller because the session daemon socket management is done
1374          * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1375          */
1376         {
1377                 int ret_send_status;
1378
1379                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1380                 if (ret_send_status < 0) {
1381                         goto error_fatal;
1382                 }
1383         }
1384
1385         ret_func = 1;
1386
1387 end:
1388         health_code_update();
1389         return ret_func;
1390 }
1391
1392 /*
1393  * Sync metadata meaning request them to the session daemon and snapshot to the
1394  * metadata thread can consumer them.
1395  *
1396  * Metadata stream lock MUST be acquired.
1397  */
1398 enum sync_metadata_status lttng_kconsumer_sync_metadata(struct lttng_consumer_stream *metadata)
1399 {
1400         int ret;
1401         enum sync_metadata_status status;
1402
1403         LTTNG_ASSERT(metadata);
1404
1405         ret = kernctl_buffer_flush(metadata->wait_fd);
1406         if (ret < 0) {
1407                 ERR("Failed to flush kernel stream");
1408                 status = SYNC_METADATA_STATUS_ERROR;
1409                 goto end;
1410         }
1411
1412         ret = kernctl_snapshot(metadata->wait_fd);
1413         if (ret < 0) {
1414                 if (errno == EAGAIN) {
1415                         /* No new metadata, exit. */
1416                         DBG("Sync metadata, no new kernel metadata");
1417                         status = SYNC_METADATA_STATUS_NO_DATA;
1418                 } else {
1419                         ERR("Sync metadata, taking kernel snapshot failed.");
1420                         status = SYNC_METADATA_STATUS_ERROR;
1421                 }
1422         } else {
1423                 status = SYNC_METADATA_STATUS_NEW_DATA;
1424         }
1425
1426 end:
1427         return status;
1428 }
1429
1430 static int extract_common_subbuffer_info(struct lttng_consumer_stream *stream,
1431                                          struct stream_subbuffer *subbuf)
1432 {
1433         int ret;
1434
1435         ret = kernctl_get_subbuf_size(stream->wait_fd, &subbuf->info.data.subbuf_size);
1436         if (ret) {
1437                 goto end;
1438         }
1439
1440         ret = kernctl_get_padded_subbuf_size(stream->wait_fd,
1441                                              &subbuf->info.data.padded_subbuf_size);
1442         if (ret) {
1443                 goto end;
1444         }
1445
1446 end:
1447         return ret;
1448 }
1449
1450 static int extract_metadata_subbuffer_info(struct lttng_consumer_stream *stream,
1451                                            struct stream_subbuffer *subbuf)
1452 {
1453         int ret;
1454
1455         ret = extract_common_subbuffer_info(stream, subbuf);
1456         if (ret) {
1457                 goto end;
1458         }
1459
1460         ret = kernctl_get_metadata_version(stream->wait_fd, &subbuf->info.metadata.version);
1461         if (ret) {
1462                 goto end;
1463         }
1464
1465 end:
1466         return ret;
1467 }
1468
1469 static int extract_data_subbuffer_info(struct lttng_consumer_stream *stream,
1470                                        struct stream_subbuffer *subbuf)
1471 {
1472         int ret;
1473
1474         ret = extract_common_subbuffer_info(stream, subbuf);
1475         if (ret) {
1476                 goto end;
1477         }
1478
1479         ret = kernctl_get_packet_size(stream->wait_fd, &subbuf->info.data.packet_size);
1480         if (ret < 0) {
1481                 PERROR("Failed to get sub-buffer packet size");
1482                 goto end;
1483         }
1484
1485         ret = kernctl_get_content_size(stream->wait_fd, &subbuf->info.data.content_size);
1486         if (ret < 0) {
1487                 PERROR("Failed to get sub-buffer content size");
1488                 goto end;
1489         }
1490
1491         ret = kernctl_get_timestamp_begin(stream->wait_fd, &subbuf->info.data.timestamp_begin);
1492         if (ret < 0) {
1493                 PERROR("Failed to get sub-buffer begin timestamp");
1494                 goto end;
1495         }
1496
1497         ret = kernctl_get_timestamp_end(stream->wait_fd, &subbuf->info.data.timestamp_end);
1498         if (ret < 0) {
1499                 PERROR("Failed to get sub-buffer end timestamp");
1500                 goto end;
1501         }
1502
1503         ret = kernctl_get_events_discarded(stream->wait_fd, &subbuf->info.data.events_discarded);
1504         if (ret) {
1505                 PERROR("Failed to get sub-buffer events discarded count");
1506                 goto end;
1507         }
1508
1509         ret = kernctl_get_sequence_number(stream->wait_fd,
1510                                           &subbuf->info.data.sequence_number.value);
1511         if (ret) {
1512                 /* May not be supported by older LTTng-modules. */
1513                 if (ret != -ENOTTY) {
1514                         PERROR("Failed to get sub-buffer sequence number");
1515                         goto end;
1516                 }
1517         } else {
1518                 subbuf->info.data.sequence_number.is_set = true;
1519         }
1520
1521         ret = kernctl_get_stream_id(stream->wait_fd, &subbuf->info.data.stream_id);
1522         if (ret < 0) {
1523                 PERROR("Failed to get stream id");
1524                 goto end;
1525         }
1526
1527         ret = kernctl_get_instance_id(stream->wait_fd, &subbuf->info.data.stream_instance_id.value);
1528         if (ret) {
1529                 /* May not be supported by older LTTng-modules. */
1530                 if (ret != -ENOTTY) {
1531                         PERROR("Failed to get stream instance id");
1532                         goto end;
1533                 }
1534         } else {
1535                 subbuf->info.data.stream_instance_id.is_set = true;
1536         }
1537 end:
1538         return ret;
1539 }
1540
1541 static enum get_next_subbuffer_status get_subbuffer_common(struct lttng_consumer_stream *stream,
1542                                                            struct stream_subbuffer *subbuffer)
1543 {
1544         int ret;
1545         enum get_next_subbuffer_status status;
1546
1547         ret = kernctl_get_next_subbuf(stream->wait_fd);
1548         switch (ret) {
1549         case 0:
1550                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1551                 break;
1552         case -ENODATA:
1553         case -EAGAIN:
1554                 /*
1555                  * The caller only expects -ENODATA when there is no data to
1556                  * read, but the kernel tracer returns -EAGAIN when there is
1557                  * currently no data for a non-finalized stream, and -ENODATA
1558                  * when there is no data for a finalized stream. Those can be
1559                  * combined into a -ENODATA return value.
1560                  */
1561                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1562                 goto end;
1563         default:
1564                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1565                 goto end;
1566         }
1567
1568         ret = stream->read_subbuffer_ops.extract_subbuffer_info(stream, subbuffer);
1569         if (ret) {
1570                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1571         }
1572 end:
1573         return status;
1574 }
1575
1576 static enum get_next_subbuffer_status
1577 get_next_subbuffer_splice(struct lttng_consumer_stream *stream, struct stream_subbuffer *subbuffer)
1578 {
1579         const enum get_next_subbuffer_status status = get_subbuffer_common(stream, subbuffer);
1580
1581         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1582                 goto end;
1583         }
1584
1585         subbuffer->buffer.fd = stream->wait_fd;
1586 end:
1587         return status;
1588 }
1589
1590 static enum get_next_subbuffer_status get_next_subbuffer_mmap(struct lttng_consumer_stream *stream,
1591                                                               struct stream_subbuffer *subbuffer)
1592 {
1593         int ret;
1594         enum get_next_subbuffer_status status;
1595         const char *addr;
1596
1597         status = get_subbuffer_common(stream, subbuffer);
1598         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1599                 goto end;
1600         }
1601
1602         ret = get_current_subbuf_addr(stream, &addr);
1603         if (ret) {
1604                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1605                 goto end;
1606         }
1607
1608         subbuffer->buffer.buffer =
1609                 lttng_buffer_view_init(addr, 0, subbuffer->info.data.padded_subbuf_size);
1610 end:
1611         return status;
1612 }
1613
1614 static enum get_next_subbuffer_status
1615 get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
1616                                   struct stream_subbuffer *subbuffer)
1617 {
1618         int ret;
1619         const char *addr;
1620         bool coherent;
1621         enum get_next_subbuffer_status status;
1622
1623         ret = kernctl_get_next_subbuf_metadata_check(stream->wait_fd, &coherent);
1624         if (ret) {
1625                 goto end;
1626         }
1627
1628         ret = stream->read_subbuffer_ops.extract_subbuffer_info(stream, subbuffer);
1629         if (ret) {
1630                 goto end;
1631         }
1632
1633         LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
1634
1635         ret = get_current_subbuf_addr(stream, &addr);
1636         if (ret) {
1637                 goto end;
1638         }
1639
1640         subbuffer->buffer.buffer =
1641                 lttng_buffer_view_init(addr, 0, subbuffer->info.data.padded_subbuf_size);
1642         DBG("Got metadata packet with padded_subbuf_size = %lu, coherent = %s",
1643             subbuffer->info.metadata.padded_subbuf_size,
1644             coherent ? "true" : "false");
1645 end:
1646         /*
1647          * The caller only expects -ENODATA when there is no data to read, but
1648          * the kernel tracer returns -EAGAIN when there is currently no data
1649          * for a non-finalized stream, and -ENODATA when there is no data for a
1650          * finalized stream. Those can be combined into a -ENODATA return value.
1651          */
1652         switch (ret) {
1653         case 0:
1654                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1655                 break;
1656         case -ENODATA:
1657         case -EAGAIN:
1658                 /*
1659                  * The caller only expects -ENODATA when there is no data to
1660                  * read, but the kernel tracer returns -EAGAIN when there is
1661                  * currently no data for a non-finalized stream, and -ENODATA
1662                  * when there is no data for a finalized stream. Those can be
1663                  * combined into a -ENODATA return value.
1664                  */
1665                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1666                 break;
1667         default:
1668                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1669                 break;
1670         }
1671
1672         return status;
1673 }
1674
1675 static int put_next_subbuffer(struct lttng_consumer_stream *stream,
1676                               struct stream_subbuffer *subbuffer __attribute__((unused)))
1677 {
1678         const int ret = kernctl_put_next_subbuf(stream->wait_fd);
1679
1680         if (ret) {
1681                 if (ret == -EFAULT) {
1682                         PERROR("Error in unreserving sub buffer");
1683                 } else if (ret == -EIO) {
1684                         /* Should never happen with newer LTTng versions */
1685                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted");
1686                 }
1687         }
1688
1689         return ret;
1690 }
1691
1692 static bool is_get_next_check_metadata_available(int tracer_fd)
1693 {
1694         const int ret = kernctl_get_next_subbuf_metadata_check(tracer_fd, nullptr);
1695         const bool available = ret != -ENOTTY;
1696
1697         if (ret == 0) {
1698                 /* get succeeded, make sure to put the subbuffer. */
1699                 kernctl_put_subbuf(tracer_fd);
1700         }
1701
1702         return available;
1703 }
1704
1705 static int signal_metadata(struct lttng_consumer_stream *stream,
1706                            struct lttng_consumer_local_data *ctx __attribute__((unused)))
1707 {
1708         ASSERT_LOCKED(stream->metadata_rdv_lock);
1709         return pthread_cond_broadcast(&stream->metadata_rdv) ? -errno : 0;
1710 }
1711
1712 static int lttng_kconsumer_set_stream_ops(struct lttng_consumer_stream *stream)
1713 {
1714         int ret = 0;
1715
1716         if (stream->metadata_flag && stream->chan->is_live) {
1717                 DBG("Attempting to enable metadata bucketization for live consumers");
1718                 if (is_get_next_check_metadata_available(stream->wait_fd)) {
1719                         DBG("Kernel tracer supports get_next_subbuffer_metadata_check, metadata will be accumulated until a coherent state is reached");
1720                         stream->read_subbuffer_ops.get_next_subbuffer =
1721                                 get_next_subbuffer_metadata_check;
1722                         ret = consumer_stream_enable_metadata_bucketization(stream);
1723                         if (ret) {
1724                                 goto end;
1725                         }
1726                 } else {
1727                         /*
1728                          * The kernel tracer version is too old to indicate
1729                          * when the metadata stream has reached a "coherent"
1730                          * (parseable) point.
1731                          *
1732                          * This means that a live viewer may see an incoherent
1733                          * sequence of metadata and fail to parse it.
1734                          */
1735                         WARN("Kernel tracer does not support get_next_subbuffer_metadata_check which may cause live clients to fail to parse the metadata stream");
1736                         metadata_bucket_destroy(stream->metadata_bucket);
1737                         stream->metadata_bucket = nullptr;
1738                 }
1739
1740                 stream->read_subbuffer_ops.on_sleep = signal_metadata;
1741         }
1742
1743         if (!stream->read_subbuffer_ops.get_next_subbuffer) {
1744                 if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
1745                         stream->read_subbuffer_ops.get_next_subbuffer = get_next_subbuffer_mmap;
1746                 } else {
1747                         stream->read_subbuffer_ops.get_next_subbuffer = get_next_subbuffer_splice;
1748                 }
1749         }
1750
1751         if (stream->metadata_flag) {
1752                 stream->read_subbuffer_ops.extract_subbuffer_info = extract_metadata_subbuffer_info;
1753         } else {
1754                 stream->read_subbuffer_ops.extract_subbuffer_info = extract_data_subbuffer_info;
1755                 if (stream->chan->is_live) {
1756                         stream->read_subbuffer_ops.send_live_beacon = consumer_flush_kernel_index;
1757                 }
1758         }
1759
1760         stream->read_subbuffer_ops.put_next_subbuffer = put_next_subbuffer;
1761 end:
1762         return ret;
1763 }
1764
1765 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1766 {
1767         int ret;
1768
1769         LTTNG_ASSERT(stream);
1770
1771         /*
1772          * Don't create anything if this is set for streaming or if there is
1773          * no current trace chunk on the parent channel.
1774          */
1775         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor &&
1776             stream->chan->trace_chunk) {
1777                 ret = consumer_stream_create_output_files(stream, true);
1778                 if (ret) {
1779                         goto error;
1780                 }
1781         }
1782
1783         if (stream->output == LTTNG_EVENT_MMAP) {
1784                 /* get the len of the mmap region */
1785                 unsigned long mmap_len;
1786
1787                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1788                 if (ret != 0) {
1789                         PERROR("kernctl_get_mmap_len");
1790                         goto error_close_fd;
1791                 }
1792                 stream->mmap_len = (size_t) mmap_len;
1793
1794                 stream->mmap_base =
1795                         mmap(nullptr, stream->mmap_len, PROT_READ, MAP_PRIVATE, stream->wait_fd, 0);
1796                 if (stream->mmap_base == MAP_FAILED) {
1797                         PERROR("Error mmaping");
1798                         ret = -1;
1799                         goto error_close_fd;
1800                 }
1801         }
1802
1803         ret = lttng_kconsumer_set_stream_ops(stream);
1804         if (ret) {
1805                 goto error_close_fd;
1806         }
1807
1808         /* we return 0 to let the library handle the FD internally */
1809         return 0;
1810
1811 error_close_fd:
1812         if (stream->out_fd >= 0) {
1813                 int err;
1814
1815                 err = close(stream->out_fd);
1816                 LTTNG_ASSERT(!err);
1817                 stream->out_fd = -1;
1818         }
1819 error:
1820         return ret;
1821 }
1822
1823 /*
1824  * Check if data is still being extracted from the buffers for a specific
1825  * stream. Consumer data lock MUST be acquired before calling this function
1826  * and the stream lock.
1827  *
1828  * Return 1 if the traced data are still getting read else 0 meaning that the
1829  * data is available for trace viewer reading.
1830  */
1831 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1832 {
1833         int ret;
1834
1835         LTTNG_ASSERT(stream);
1836
1837         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1838                 ret = 0;
1839                 goto end;
1840         }
1841
1842         ret = kernctl_get_next_subbuf(stream->wait_fd);
1843         if (ret == 0) {
1844                 /* There is still data so let's put back this subbuffer. */
1845                 ret = kernctl_put_subbuf(stream->wait_fd);
1846                 LTTNG_ASSERT(ret == 0);
1847                 ret = 1; /* Data is pending */
1848                 goto end;
1849         }
1850
1851         /* Data is NOT pending and ready to be read. */
1852         ret = 0;
1853
1854 end:
1855         return ret;
1856 }