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

   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 <assert.h>
  12 #include <poll.h>
  13 #include <pthread.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/mman.h>
  17 #include <sys/socket.h>
  18 #include <sys/types.h>
  19 #include <inttypes.h>
  20 #include <unistd.h>
  21 #include <sys/stat.h>
  22 #include <stdint.h>
  23
  24 #include <bin/lttng-consumerd/health-consumerd.h>
  25 #include <common/common.h>
  26 #include <common/kernel-ctl/kernel-ctl.h>
  27 #include <common/sessiond-comm/sessiond-comm.h>
  28 #include <common/sessiond-comm/relayd.h>
  29 #include <common/compat/fcntl.h>
  30 #include <common/compat/endian.h>
  31 #include <common/pipe.h>
  32 #include <common/relayd/relayd.h>
  33 #include <common/utils.h>
  34 #include <common/consumer/consumer-stream.h>
  35 #include <common/index/index.h>
  36 #include <common/consumer/consumer-timer.h>
  37 #include <common/optional.h>
  38 #include <common/buffer-view.h>
  39 #include <common/consumer/consumer.h>
  40 #include <common/consumer/metadata-bucket.h>
  41
  42 #include "kernel-consumer.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(
  75                 struct lttng_consumer_stream *stream)
  76 {
  77         assert(stream);
  78
  79         return kernctl_snapshot_sample_positions(stream->wait_fd);
  80 }
  81
  82 /*
  83  * Get the produced position
  84  *
  85  * Returns 0 on success, < 0 on error
  86  */
  87 int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
  88                 unsigned long *pos)
  89 {
  90         int ret;
  91         int infd = stream->wait_fd;
  92
  93         ret = kernctl_snapshot_get_produced(infd, pos);
  94         if (ret != 0) {
  95                 PERROR("kernctl_snapshot_get_produced");
  96         }
  97
  98         return ret;
  99 }
 100
 101 /*
 102  * Get the consumerd position
 103  *
 104  * Returns 0 on success, < 0 on error
 105  */
 106 int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
 107                 unsigned long *pos)
 108 {
 109         int ret;
 110         int infd = stream->wait_fd;
 111
 112         ret = kernctl_snapshot_get_consumed(infd, pos);
 113         if (ret != 0) {
 114                 PERROR("kernctl_snapshot_get_consumed");
 115         }
 116
 117         return ret;
 118 }
 119
 120 static
 121 int get_current_subbuf_addr(struct lttng_consumer_stream *stream,
 122                 const char **addr)
 123 {
 124         int ret;
 125         unsigned long mmap_offset;
 126         const char *mmap_base = stream->mmap_base;
 127
 128         ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
 129         if (ret < 0) {
 130                 PERROR("Failed to get mmap read offset");
 131                 goto error;
 132         }
 133
 134         *addr = mmap_base + mmap_offset;
 135 error:
 136         return ret;
 137 }
 138
 139 /*
 140  * Take a snapshot of all the stream of a channel
 141  * RCU read-side lock must be held across this function to ensure existence of
 142  * channel.
 143  *
 144  * Returns 0 on success, < 0 on error
 145  */
 146 static int lttng_kconsumer_snapshot_channel(
 147                 struct lttng_consumer_channel *channel,
 148                 uint64_t key, char *path, uint64_t relayd_id,
 149                 uint64_t nb_packets_per_stream,
 150                 struct lttng_consumer_local_data *ctx)
 151 {
 152         int ret;
 153         struct lttng_consumer_stream *stream;
 154
 155         DBG("Kernel consumer snapshot channel %" PRIu64, key);
 156
 157         /* Prevent channel modifications while we perform the snapshot.*/
 158         pthread_mutex_lock(&channel->lock);
 159
 160         rcu_read_lock();
 161
 162         /* Splice is not supported yet for channel snapshot. */
 163         if (channel->output != CONSUMER_CHANNEL_MMAP) {
 164                 ERR("Unsupported output type for channel \"%s\": mmap output is required to record a snapshot",
 165                                 channel->name);
 166                 ret = -1;
 167                 goto end;
 168         }
 169
 170         cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
 171                 unsigned long consumed_pos, produced_pos;
 172
 173                 health_code_update();
 174
 175                 /*
 176                  * Lock stream because we are about to change its state.
 177                  */
 178                 pthread_mutex_lock(&stream->lock);
 179
 180                 assert(channel->trace_chunk);
 181                 if (!lttng_trace_chunk_get(channel->trace_chunk)) {
 182                         /*
 183                          * Can't happen barring an internal error as the channel
 184                          * holds a reference to the trace chunk.
 185                          */
 186                         ERR("Failed to acquire reference to channel's trace chunk");
 187                         ret = -1;
 188                         goto end_unlock;
 189                 }
 190                 assert(!stream->trace_chunk);
 191                 stream->trace_chunk = channel->trace_chunk;
 192
 193                 /*
 194                  * Assign the received relayd ID so we can use it for streaming. The streams
 195                  * are not visible to anyone so this is OK to change it.
 196                  */
 197                 stream->net_seq_idx = relayd_id;
 198                 channel->relayd_id = relayd_id;
 199                 if (relayd_id != (uint64_t) -1ULL) {
 200                         ret = consumer_send_relayd_stream(stream, path);
 201                         if (ret < 0) {
 202                                 ERR("sending stream to relayd");
 203                                 goto end_unlock;
 204                         }
 205                 } else {
 206                         ret = consumer_stream_create_output_files(stream,
 207                                         false);
 208                         if (ret < 0) {
 209                                 goto end_unlock;
 210                         }
 211                         DBG("Kernel consumer snapshot stream (%" PRIu64 ")",
 212                                         stream->key);
 213                 }
 214
 215                 ret = kernctl_buffer_flush_empty(stream->wait_fd);
 216                 if (ret < 0) {
 217                         /*
 218                          * Doing a buffer flush which does not take into
 219                          * account empty packets. This is not perfect
 220                          * for stream intersection, but required as a
 221                          * fall-back when "flush_empty" is not
 222                          * implemented by lttng-modules.
 223                          */
 224                         ret = kernctl_buffer_flush(stream->wait_fd);
 225                         if (ret < 0) {
 226                                 ERR("Failed to flush kernel stream");
 227                                 goto end_unlock;
 228                         }
 229                         goto end_unlock;
 230                 }
 231
 232                 ret = lttng_kconsumer_take_snapshot(stream);
 233                 if (ret < 0) {
 234                         ERR("Taking kernel snapshot");
 235                         goto end_unlock;
 236                 }
 237
 238                 ret = lttng_kconsumer_get_produced_snapshot(stream, &produced_pos);
 239                 if (ret < 0) {
 240                         ERR("Produced kernel snapshot position");
 241                         goto end_unlock;
 242                 }
 243
 244                 ret = lttng_kconsumer_get_consumed_snapshot(stream, &consumed_pos);
 245                 if (ret < 0) {
 246                         ERR("Consumerd kernel snapshot position");
 247                         goto end_unlock;
 248                 }
 249
 250                 consumed_pos = consumer_get_consume_start_pos(consumed_pos,
 251                                 produced_pos, nb_packets_per_stream,
 252                                 stream->max_sb_size);
 253
 254                 while ((long) (consumed_pos - produced_pos) < 0) {
 255                         ssize_t read_len;
 256                         unsigned long len, padded_len;
 257                         const char *subbuf_addr;
 258                         struct lttng_buffer_view subbuf_view;
 259
 260                         health_code_update();
 261                         DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 262
 263                         ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
 264                         if (ret < 0) {
 265                                 if (ret != -EAGAIN) {
 266                                         PERROR("kernctl_get_subbuf snapshot");
 267                                         goto end_unlock;
 268                                 }
 269                                 DBG("Kernel consumer get subbuf failed. Skipping it.");
 270                                 consumed_pos += stream->max_sb_size;
 271                                 stream->chan->lost_packets++;
 272                                 continue;
 273                         }
 274
 275                         ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
 276                         if (ret < 0) {
 277                                 ERR("Snapshot kernctl_get_subbuf_size");
 278                                 goto error_put_subbuf;
 279                         }
 280
 281                         ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
 282                         if (ret < 0) {
 283                                 ERR("Snapshot kernctl_get_padded_subbuf_size");
 284                                 goto error_put_subbuf;
 285                         }
 286
 287                         ret = get_current_subbuf_addr(stream, &subbuf_addr);
 288                         if (ret) {
 289                                 goto error_put_subbuf;
 290                         }
 291
 292                         subbuf_view = lttng_buffer_view_init(
 293                                         subbuf_addr, 0, padded_len);
 294                         read_len = lttng_consumer_on_read_subbuffer_mmap(
 295                                         stream, &subbuf_view,
 296                                         padded_len - len);
 297                         /*
 298                          * We write the padded len in local tracefiles but the data len
 299                          * when using a relay. Display the error but continue processing
 300                          * to try to release the subbuffer.
 301                          */
 302                         if (relayd_id != (uint64_t) -1ULL) {
 303                                 if (read_len != len) {
 304                                         ERR("Error sending to the relay (ret: %zd != len: %lu)",
 305                                                         read_len, len);
 306                                 }
 307                         } else {
 308                                 if (read_len != padded_len) {
 309                                         ERR("Error writing to tracefile (ret: %zd != len: %lu)",
 310                                                         read_len, padded_len);
 311                                 }
 312                         }
 313
 314                         ret = kernctl_put_subbuf(stream->wait_fd);
 315                         if (ret < 0) {
 316                                 ERR("Snapshot kernctl_put_subbuf");
 317                                 goto end_unlock;
 318                         }
 319                         consumed_pos += stream->max_sb_size;
 320                 }
 321
 322                 if (relayd_id == (uint64_t) -1ULL) {
 323                         if (stream->out_fd >= 0) {
 324                                 ret = close(stream->out_fd);
 325                                 if (ret < 0) {
 326                                         PERROR("Kernel consumer snapshot close out_fd");
 327                                         goto end_unlock;
 328                                 }
 329                                 stream->out_fd = -1;
 330                         }
 331                 } else {
 332                         close_relayd_stream(stream);
 333                         stream->net_seq_idx = (uint64_t) -1ULL;
 334                 }
 335                 lttng_trace_chunk_put(stream->trace_chunk);
 336                 stream->trace_chunk = NULL;
 337                 pthread_mutex_unlock(&stream->lock);
 338         }
 339
 340         /* All good! */
 341         ret = 0;
 342         goto end;
 343
 344 error_put_subbuf:
 345         ret = kernctl_put_subbuf(stream->wait_fd);
 346         if (ret < 0) {
 347                 ERR("Snapshot kernctl_put_subbuf error path");
 348         }
 349 end_unlock:
 350         pthread_mutex_unlock(&stream->lock);
 351 end:
 352         rcu_read_unlock();
 353         pthread_mutex_unlock(&channel->lock);
 354         return ret;
 355 }
 356
 357 /*
 358  * Read the whole metadata available for a snapshot.
 359  * RCU read-side lock must be held across this function to ensure existence of
 360  * metadata_channel.
 361  *
 362  * Returns 0 on success, < 0 on error
 363  */
 364 static int lttng_kconsumer_snapshot_metadata(
 365                 struct lttng_consumer_channel *metadata_channel,
 366                 uint64_t key, char *path, uint64_t relayd_id,
 367                 struct lttng_consumer_local_data *ctx)
 368 {
 369         int ret, use_relayd = 0;
 370         ssize_t ret_read;
 371         struct lttng_consumer_stream *metadata_stream;
 372
 373         assert(ctx);
 374
 375         DBG("Kernel consumer snapshot metadata with key %" PRIu64 " at path %s",
 376                         key, path);
 377
 378         rcu_read_lock();
 379
 380         metadata_stream = metadata_channel->metadata_stream;
 381         assert(metadata_stream);
 382
 383         metadata_stream->read_subbuffer_ops.lock(metadata_stream);
 384         assert(metadata_channel->trace_chunk);
 385         assert(metadata_stream->trace_chunk);
 386
 387         /* Flag once that we have a valid relayd for the stream. */
 388         if (relayd_id != (uint64_t) -1ULL) {
 389                 use_relayd = 1;
 390         }
 391
 392         if (use_relayd) {
 393                 ret = consumer_send_relayd_stream(metadata_stream, path);
 394                 if (ret < 0) {
 395                         goto error_snapshot;
 396                 }
 397         } else {
 398                 ret = consumer_stream_create_output_files(metadata_stream,
 399                                 false);
 400                 if (ret < 0) {
 401                         goto error_snapshot;
 402                 }
 403         }
 404
 405         do {
 406                 health_code_update();
 407
 408                 ret_read = lttng_consumer_read_subbuffer(metadata_stream, ctx, true);
 409                 if (ret_read < 0) {
 410                         ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
 411                                         ret_read);
 412                         ret = ret_read;
 413                         goto error_snapshot;
 414                 }
 415         } while (ret_read > 0);
 416
 417         if (use_relayd) {
 418                 close_relayd_stream(metadata_stream);
 419                 metadata_stream->net_seq_idx = (uint64_t) -1ULL;
 420         } else {
 421                 if (metadata_stream->out_fd >= 0) {
 422                         ret = close(metadata_stream->out_fd);
 423                         if (ret < 0) {
 424                                 PERROR("Kernel consumer snapshot metadata close out_fd");
 425                                 /*
 426                                  * Don't go on error here since the snapshot was successful at this
 427                                  * point but somehow the close failed.
 428                                  */
 429                         }
 430                         metadata_stream->out_fd = -1;
 431                         lttng_trace_chunk_put(metadata_stream->trace_chunk);
 432                         metadata_stream->trace_chunk = NULL;
 433                 }
 434         }
 435
 436         ret = 0;
 437 error_snapshot:
 438         metadata_stream->read_subbuffer_ops.unlock(metadata_stream);
 439         cds_list_del(&metadata_stream->send_node);
 440         consumer_stream_destroy(metadata_stream, NULL);
 441         metadata_channel->metadata_stream = NULL;
 442         rcu_read_unlock();
 443         return ret;
 444 }
 445
 446 /*
 447  * Receive command from session daemon and process it.
 448  *
 449  * Return 1 on success else a negative value or 0.
 450  */
 451 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 452                 int sock, struct pollfd *consumer_sockpoll)
 453 {
 454         int ret_func;
 455         enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 456         struct lttcomm_consumer_msg msg;
 457
 458         health_code_update();
 459
 460         {
 461                 ssize_t ret_recv;
 462
 463                 ret_recv = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 464                 if (ret_recv != sizeof(msg)) {
 465                         if (ret_recv > 0) {
 466                                 lttng_consumer_send_error(ctx,
 467                                                 LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 468                                 ret_recv = -1;
 469                         }
 470                         return ret_recv;
 471                 }
 472         }
 473
 474         health_code_update();
 475
 476         /* Deprecated command */
 477         assert(msg.cmd_type != LTTNG_CONSUMER_STOP);
 478
 479         health_code_update();
 480
 481         /* relayd needs RCU read-side protection */
 482         rcu_read_lock();
 483
 484         switch (msg.cmd_type) {
 485         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 486         {
 487                 uint32_t major = msg.u.relayd_sock.major;
 488                 uint32_t minor = msg.u.relayd_sock.minor;
 489                 enum lttcomm_sock_proto protocol = (enum lttcomm_sock_proto)
 490                                 msg.u.relayd_sock.relayd_socket_protocol;
 491
 492                 /* Session daemon status message are handled in the following call. */
 493                 consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 494                                 msg.u.relayd_sock.type, ctx, sock,
 495                                 consumer_sockpoll, msg.u.relayd_sock.session_id,
 496                                 msg.u.relayd_sock.relayd_session_id, major,
 497                                 minor, protocol);
 498                 goto end_nosignal;
 499         }
 500         case LTTNG_CONSUMER_ADD_CHANNEL:
 501         {
 502                 struct lttng_consumer_channel *new_channel;
 503                 int ret_send_status, ret_add_channel = 0;
 504                 const uint64_t chunk_id = msg.u.channel.chunk_id.value;
 505
 506                 health_code_update();
 507
 508                 /* First send a status message before receiving the fds. */
 509                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 510                 if (ret_send_status < 0) {
 511                         /* Somehow, the session daemon is not responding anymore. */
 512                         goto error_fatal;
 513                 }
 514
 515                 health_code_update();
 516
 517                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 518                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 519                                 msg.u.channel.session_id,
 520                                 msg.u.channel.chunk_id.is_set ?
 521                                                 &chunk_id : NULL,
 522                                 msg.u.channel.pathname,
 523                                 msg.u.channel.name,
 524                                 msg.u.channel.relayd_id, msg.u.channel.output,
 525                                 msg.u.channel.tracefile_size,
 526                                 msg.u.channel.tracefile_count, 0,
 527                                 msg.u.channel.monitor,
 528                                 msg.u.channel.live_timer_interval,
 529                                 msg.u.channel.is_live,
 530                                 NULL, NULL);
 531                 if (new_channel == NULL) {
 532                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 533                         goto end_nosignal;
 534                 }
 535                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 536                 switch (msg.u.channel.output) {
 537                 case LTTNG_EVENT_SPLICE:
 538                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 539                         break;
 540                 case LTTNG_EVENT_MMAP:
 541                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 542                         break;
 543                 default:
 544                         ERR("Channel output unknown %d", msg.u.channel.output);
 545                         goto end_nosignal;
 546                 }
 547
 548                 /* Translate and save channel type. */
 549                 switch (msg.u.channel.type) {
 550                 case CONSUMER_CHANNEL_TYPE_DATA:
 551                 case CONSUMER_CHANNEL_TYPE_METADATA:
 552                         new_channel->type = msg.u.channel.type;
 553                         break;
 554                 default:
 555                         assert(0);
 556                         goto end_nosignal;
 557                 };
 558
 559                 health_code_update();
 560
 561                 if (ctx->on_recv_channel != NULL) {
 562                         int ret_recv_channel =
 563                                         ctx->on_recv_channel(new_channel);
 564                         if (ret_recv_channel == 0) {
 565                                 ret_add_channel = consumer_add_channel(
 566                                                 new_channel, ctx);
 567                         } else if (ret_recv_channel < 0) {
 568                                 goto end_nosignal;
 569                         }
 570                 } else {
 571                         ret_add_channel =
 572                                         consumer_add_channel(new_channel, ctx);
 573                 }
 574                 if (msg.u.channel.type == CONSUMER_CHANNEL_TYPE_DATA &&
 575                                 !ret_add_channel) {
 576                         int monitor_start_ret;
 577
 578                         DBG("Consumer starting monitor timer");
 579                         consumer_timer_live_start(new_channel,
 580                                         msg.u.channel.live_timer_interval);
 581                         monitor_start_ret = consumer_timer_monitor_start(
 582                                         new_channel,
 583                                         msg.u.channel.monitor_timer_interval);
 584                         if (monitor_start_ret < 0) {
 585                                 ERR("Starting channel monitoring timer failed");
 586                                 goto end_nosignal;
 587                         }
 588                 }
 589
 590                 health_code_update();
 591
 592                 /* If we received an error in add_channel, we need to report it. */
 593                 if (ret_add_channel < 0) {
 594                         ret_send_status = consumer_send_status_msg(
 595                                         sock, ret_add_channel);
 596                         if (ret_send_status < 0) {
 597                                 goto error_fatal;
 598                         }
 599                         goto end_nosignal;
 600                 }
 601
 602                 goto end_nosignal;
 603         }
 604         case LTTNG_CONSUMER_ADD_STREAM:
 605         {
 606                 int fd;
 607                 struct lttng_pipe *stream_pipe;
 608                 struct lttng_consumer_stream *new_stream;
 609                 struct lttng_consumer_channel *channel;
 610                 int alloc_ret = 0;
 611                 int ret_send_status, ret_poll, ret_get_max_subbuf_size;
 612                 ssize_t ret_pipe_write, ret_recv;
 613
 614                 /*
 615                  * Get stream's channel reference. Needed when adding the stream to the
 616                  * global hash table.
 617                  */
 618                 channel = consumer_find_channel(msg.u.stream.channel_key);
 619                 if (!channel) {
 620                         /*
 621                          * We could not find the channel. Can happen if cpu hotplug
 622                          * happens while tearing down.
 623                          */
 624                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 625                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 626                 }
 627
 628                 health_code_update();
 629
 630                 /* First send a status message before receiving the fds. */
 631                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 632                 if (ret_send_status < 0) {
 633                         /* Somehow, the session daemon is not responding anymore. */
 634                         goto error_add_stream_fatal;
 635                 }
 636
 637                 health_code_update();
 638
 639                 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 640                         /* Channel was not found. */
 641                         goto error_add_stream_nosignal;
 642                 }
 643
 644                 /* Blocking call */
 645                 health_poll_entry();
 646                 ret_poll = lttng_consumer_poll_socket(consumer_sockpoll);
 647                 health_poll_exit();
 648                 if (ret_poll) {
 649                         goto error_add_stream_fatal;
 650                 }
 651
 652                 health_code_update();
 653
 654                 /* Get stream file descriptor from socket */
 655                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 656                 if (ret_recv != sizeof(fd)) {
 657                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 658                         ret_func = ret_recv;
 659                         goto end;
 660                 }
 661
 662                 health_code_update();
 663
 664                 /*
 665                  * Send status code to session daemon only if the recv works. If the
 666                  * above recv() failed, the session daemon is notified through the
 667                  * error socket and the teardown is eventually done.
 668                  */
 669                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 670                 if (ret_send_status < 0) {
 671                         /* Somehow, the session daemon is not responding anymore. */
 672                         goto error_add_stream_nosignal;
 673                 }
 674
 675                 health_code_update();
 676
 677                 pthread_mutex_lock(&channel->lock);
 678                 new_stream = consumer_stream_create(
 679                                 channel,
 680                                 channel->key,
 681                                 fd,
 682                                 channel->name,
 683                                 channel->relayd_id,
 684                                 channel->session_id,
 685                                 channel->trace_chunk,
 686                                 msg.u.stream.cpu,
 687                                 &alloc_ret,
 688                                 channel->type,
 689                                 channel->monitor);
 690                 if (new_stream == NULL) {
 691                         switch (alloc_ret) {
 692                         case -ENOMEM:
 693                         case -EINVAL:
 694                         default:
 695                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 696                                 break;
 697                         }
 698                         pthread_mutex_unlock(&channel->lock);
 699                         goto error_add_stream_nosignal;
 700                 }
 701
 702                 new_stream->wait_fd = fd;
 703                 ret_get_max_subbuf_size = kernctl_get_max_subbuf_size(
 704                                 new_stream->wait_fd, &new_stream->max_sb_size);
 705                 if (ret_get_max_subbuf_size < 0) {
 706                         pthread_mutex_unlock(&channel->lock);
 707                         ERR("Failed to get kernel maximal subbuffer size");
 708                         goto error_add_stream_nosignal;
 709                 }
 710
 711                 consumer_stream_update_channel_attributes(new_stream,
 712                                 channel);
 713
 714                 /*
 715                  * We've just assigned the channel to the stream so increment the
 716                  * refcount right now. We don't need to increment the refcount for
 717                  * streams in no monitor because we handle manually the cleanup of
 718                  * those. It is very important to make sure there is NO prior
 719                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 720                  */
 721                 if (channel->monitor) {
 722                         uatomic_inc(&new_stream->chan->refcount);
 723                 }
 724
 725                 /*
 726                  * The buffer flush is done on the session daemon side for the kernel
 727                  * so no need for the stream "hangup_flush_done" variable to be
 728                  * tracked. This is important for a kernel stream since we don't rely
 729                  * on the flush state of the stream to read data. It's not the case for
 730                  * user space tracing.
 731                  */
 732                 new_stream->hangup_flush_done = 0;
 733
 734                 health_code_update();
 735
 736                 pthread_mutex_lock(&new_stream->lock);
 737                 if (ctx->on_recv_stream) {
 738                         int ret_recv_stream = ctx->on_recv_stream(new_stream);
 739                         if (ret_recv_stream < 0) {
 740                                 pthread_mutex_unlock(&new_stream->lock);
 741                                 pthread_mutex_unlock(&channel->lock);
 742                                 consumer_stream_free(new_stream);
 743                                 goto error_add_stream_nosignal;
 744                         }
 745                 }
 746                 health_code_update();
 747
 748                 if (new_stream->metadata_flag) {
 749                         channel->metadata_stream = new_stream;
 750                 }
 751
 752                 /* Do not monitor this stream. */
 753                 if (!channel->monitor) {
 754                         DBG("Kernel consumer add stream %s in no monitor mode with "
 755                                         "relayd id %" PRIu64, new_stream->name,
 756                                         new_stream->net_seq_idx);
 757                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 758                         pthread_mutex_unlock(&new_stream->lock);
 759                         pthread_mutex_unlock(&channel->lock);
 760                         goto end_add_stream;
 761                 }
 762
 763                 /* Send stream to relayd if the stream has an ID. */
 764                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 765                         int ret_send_relayd_stream;
 766
 767                         ret_send_relayd_stream = consumer_send_relayd_stream(
 768                                         new_stream, new_stream->chan->pathname);
 769                         if (ret_send_relayd_stream < 0) {
 770                                 pthread_mutex_unlock(&new_stream->lock);
 771                                 pthread_mutex_unlock(&channel->lock);
 772                                 consumer_stream_free(new_stream);
 773                                 goto error_add_stream_nosignal;
 774                         }
 775
 776                         /*
 777                          * If adding an extra stream to an already
 778                          * existing channel (e.g. cpu hotplug), we need
 779                          * to send the "streams_sent" command to relayd.
 780                          */
 781                         if (channel->streams_sent_to_relayd) {
 782                                 int ret_send_relayd_streams_sent;
 783
 784                                 ret_send_relayd_streams_sent =
 785                                                 consumer_send_relayd_streams_sent(
 786                                                                 new_stream->net_seq_idx);
 787                                 if (ret_send_relayd_streams_sent < 0) {
 788                                         pthread_mutex_unlock(&new_stream->lock);
 789                                         pthread_mutex_unlock(&channel->lock);
 790                                         goto error_add_stream_nosignal;
 791                                 }
 792                         }
 793                 }
 794                 pthread_mutex_unlock(&new_stream->lock);
 795                 pthread_mutex_unlock(&channel->lock);
 796
 797                 /* Get the right pipe where the stream will be sent. */
 798                 if (new_stream->metadata_flag) {
 799                         consumer_add_metadata_stream(new_stream);
 800                         stream_pipe = ctx->consumer_metadata_pipe;
 801                 } else {
 802                         consumer_add_data_stream(new_stream);
 803                         stream_pipe = ctx->consumer_data_pipe;
 804                 }
 805
 806                 /* Visible to other threads */
 807                 new_stream->globally_visible = 1;
 808
 809                 health_code_update();
 810
 811                 ret_pipe_write = lttng_pipe_write(
 812                                 stream_pipe, &new_stream, sizeof(new_stream));
 813                 if (ret_pipe_write < 0) {
 814                         ERR("Consumer write %s stream to pipe %d",
 815                                         new_stream->metadata_flag ? "metadata" : "data",
 816                                         lttng_pipe_get_writefd(stream_pipe));
 817                         if (new_stream->metadata_flag) {
 818                                 consumer_del_stream_for_metadata(new_stream);
 819                         } else {
 820                                 consumer_del_stream_for_data(new_stream);
 821                         }
 822                         goto error_add_stream_nosignal;
 823                 }
 824
 825                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
 826                                 new_stream->name, fd, new_stream->chan->pathname, new_stream->relayd_stream_id);
 827 end_add_stream:
 828                 break;
 829 error_add_stream_nosignal:
 830                 goto end_nosignal;
 831 error_add_stream_fatal:
 832                 goto error_fatal;
 833         }
 834         case LTTNG_CONSUMER_STREAMS_SENT:
 835         {
 836                 struct lttng_consumer_channel *channel;
 837                 int ret_send_status;
 838
 839                 /*
 840                  * Get stream's channel reference. Needed when adding the stream to the
 841                  * global hash table.
 842                  */
 843                 channel = consumer_find_channel(msg.u.sent_streams.channel_key);
 844                 if (!channel) {
 845                         /*
 846                          * We could not find the channel. Can happen if cpu hotplug
 847                          * happens while tearing down.
 848                          */
 849                         ERR("Unable to find channel key %" PRIu64,
 850                                         msg.u.sent_streams.channel_key);
 851                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 852                 }
 853
 854                 health_code_update();
 855
 856                 /*
 857                  * Send status code to session daemon.
 858                  */
 859                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 860                 if (ret_send_status < 0 ||
 861                                 ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 862                         /* Somehow, the session daemon is not responding anymore. */
 863                         goto error_streams_sent_nosignal;
 864                 }
 865
 866                 health_code_update();
 867
 868                 /*
 869                  * We should not send this message if we don't monitor the
 870                  * streams in this channel.
 871                  */
 872                 if (!channel->monitor) {
 873                         goto end_error_streams_sent;
 874                 }
 875
 876                 health_code_update();
 877                 /* Send stream to relayd if the stream has an ID. */
 878                 if (msg.u.sent_streams.net_seq_idx != (uint64_t) -1ULL) {
 879                         int ret_send_relay_streams;
 880
 881                         ret_send_relay_streams = consumer_send_relayd_streams_sent(
 882                                         msg.u.sent_streams.net_seq_idx);
 883                         if (ret_send_relay_streams < 0) {
 884                                 goto error_streams_sent_nosignal;
 885                         }
 886                         channel->streams_sent_to_relayd = true;
 887                 }
 888 end_error_streams_sent:
 889                 break;
 890 error_streams_sent_nosignal:
 891                 goto end_nosignal;
 892         }
 893         case LTTNG_CONSUMER_UPDATE_STREAM:
 894         {
 895                 rcu_read_unlock();
 896                 return -ENOSYS;
 897         }
 898         case LTTNG_CONSUMER_DESTROY_RELAYD:
 899         {
 900                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 901                 struct consumer_relayd_sock_pair *relayd;
 902                 int ret_send_status;
 903
 904                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 905
 906                 /* Get relayd reference if exists. */
 907                 relayd = consumer_find_relayd(index);
 908                 if (relayd == NULL) {
 909                         DBG("Unable to find relayd %" PRIu64, index);
 910                         ret_code = LTTCOMM_CONSUMERD_RELAYD_FAIL;
 911                 }
 912
 913                 /*
 914                  * Each relayd socket pair has a refcount of stream attached to it
 915                  * which tells if the relayd is still active or not depending on the
 916                  * refcount value.
 917                  *
 918                  * This will set the destroy flag of the relayd object and destroy it
 919                  * if the refcount reaches zero when called.
 920                  *
 921                  * The destroy can happen either here or when a stream fd hangs up.
 922                  */
 923                 if (relayd) {
 924                         consumer_flag_relayd_for_destroy(relayd);
 925                 }
 926
 927                 health_code_update();
 928
 929                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 930                 if (ret_send_status < 0) {
 931                         /* Somehow, the session daemon is not responding anymore. */
 932                         goto error_fatal;
 933                 }
 934
 935                 goto end_nosignal;
 936         }
 937         case LTTNG_CONSUMER_DATA_PENDING:
 938         {
 939                 int32_t ret_data_pending;
 940                 uint64_t id = msg.u.data_pending.session_id;
 941                 ssize_t ret_send;
 942
 943                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 944
 945                 ret_data_pending = consumer_data_pending(id);
 946
 947                 health_code_update();
 948
 949                 /* Send back returned value to session daemon */
 950                 ret_send = lttcomm_send_unix_sock(sock, &ret_data_pending,
 951                                 sizeof(ret_data_pending));
 952                 if (ret_send < 0) {
 953                         PERROR("send data pending ret code");
 954                         goto error_fatal;
 955                 }
 956
 957                 /*
 958                  * No need to send back a status message since the data pending
 959                  * returned value is the response.
 960                  */
 961                 break;
 962         }
 963         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 964         {
 965                 struct lttng_consumer_channel *channel;
 966                 uint64_t key = msg.u.snapshot_channel.key;
 967                 int ret_send_status;
 968
 969                 channel = consumer_find_channel(key);
 970                 if (!channel) {
 971                         ERR("Channel %" PRIu64 " not found", key);
 972                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 973                 } else {
 974                         if (msg.u.snapshot_channel.metadata == 1) {
 975                                 int ret_snapshot;
 976
 977                                 ret_snapshot = lttng_kconsumer_snapshot_metadata(
 978                                                 channel, key,
 979                                                 msg.u.snapshot_channel.pathname,
 980                                                 msg.u.snapshot_channel.relayd_id,
 981                                                 ctx);
 982                                 if (ret_snapshot < 0) {
 983                                         ERR("Snapshot metadata failed");
 984                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 985                                 }
 986                         } else {
 987                                 int ret_snapshot;
 988
 989                                 ret_snapshot = lttng_kconsumer_snapshot_channel(
 990                                                 channel, key,
 991                                                 msg.u.snapshot_channel.pathname,
 992                                                 msg.u.snapshot_channel.relayd_id,
 993                                                 msg.u.snapshot_channel
 994                                                                 .nb_packets_per_stream,
 995                                                 ctx);
 996                                 if (ret_snapshot < 0) {
 997                                         ERR("Snapshot channel failed");
 998                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 999                                 }
1000                         }
1001                 }
1002                 health_code_update();
1003
1004                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1005                 if (ret_send_status < 0) {
1006                         /* Somehow, the session daemon is not responding anymore. */
1007                         goto end_nosignal;
1008                 }
1009                 break;
1010         }
1011         case LTTNG_CONSUMER_DESTROY_CHANNEL:
1012         {
1013                 uint64_t key = msg.u.destroy_channel.key;
1014                 struct lttng_consumer_channel *channel;
1015                 int ret_send_status;
1016
1017                 channel = consumer_find_channel(key);
1018                 if (!channel) {
1019                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
1020                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1021                 }
1022
1023                 health_code_update();
1024
1025                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1026                 if (ret_send_status < 0) {
1027                         /* Somehow, the session daemon is not responding anymore. */
1028                         goto end_destroy_channel;
1029                 }
1030
1031                 health_code_update();
1032
1033                 /* Stop right now if no channel was found. */
1034                 if (!channel) {
1035                         goto end_destroy_channel;
1036                 }
1037
1038                 /*
1039                  * This command should ONLY be issued for channel with streams set in
1040                  * no monitor mode.
1041                  */
1042                 assert(!channel->monitor);
1043
1044                 /*
1045                  * The refcount should ALWAYS be 0 in the case of a channel in no
1046                  * monitor mode.
1047                  */
1048                 assert(!uatomic_sub_return(&channel->refcount, 1));
1049
1050                 consumer_del_channel(channel);
1051 end_destroy_channel:
1052                 goto end_nosignal;
1053         }
1054         case LTTNG_CONSUMER_DISCARDED_EVENTS:
1055         {
1056                 ssize_t ret;
1057                 uint64_t count;
1058                 struct lttng_consumer_channel *channel;
1059                 uint64_t id = msg.u.discarded_events.session_id;
1060                 uint64_t key = msg.u.discarded_events.channel_key;
1061
1062                 DBG("Kernel consumer discarded events command for session id %"
1063                                 PRIu64 ", channel key %" PRIu64, id, key);
1064
1065                 channel = consumer_find_channel(key);
1066                 if (!channel) {
1067                         ERR("Kernel consumer discarded events channel %"
1068                                         PRIu64 " not found", key);
1069                         count = 0;
1070                 } else {
1071                         count = channel->discarded_events;
1072                 }
1073
1074                 health_code_update();
1075
1076                 /* Send back returned value to session daemon */
1077                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1078                 if (ret < 0) {
1079                         PERROR("send discarded events");
1080                         goto error_fatal;
1081                 }
1082
1083                 break;
1084         }
1085         case LTTNG_CONSUMER_LOST_PACKETS:
1086         {
1087                 ssize_t ret;
1088                 uint64_t count;
1089                 struct lttng_consumer_channel *channel;
1090                 uint64_t id = msg.u.lost_packets.session_id;
1091                 uint64_t key = msg.u.lost_packets.channel_key;
1092
1093                 DBG("Kernel consumer lost packets command for session id %"
1094                                 PRIu64 ", channel key %" PRIu64, id, key);
1095
1096                 channel = consumer_find_channel(key);
1097                 if (!channel) {
1098                         ERR("Kernel consumer lost packets channel %"
1099                                         PRIu64 " not found", key);
1100                         count = 0;
1101                 } else {
1102                         count = channel->lost_packets;
1103                 }
1104
1105                 health_code_update();
1106
1107                 /* Send back returned value to session daemon */
1108                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1109                 if (ret < 0) {
1110                         PERROR("send lost packets");
1111                         goto error_fatal;
1112                 }
1113
1114                 break;
1115         }
1116         case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
1117         {
1118                 int channel_monitor_pipe;
1119                 int ret_send_status, ret_set_channel_monitor_pipe;
1120                 ssize_t ret_recv;
1121
1122                 ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1123                 /* Successfully received the command's type. */
1124                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1125                 if (ret_send_status < 0) {
1126                         goto error_fatal;
1127                 }
1128
1129                 ret_recv = lttcomm_recv_fds_unix_sock(
1130                                 sock, &channel_monitor_pipe, 1);
1131                 if (ret_recv != sizeof(channel_monitor_pipe)) {
1132                         ERR("Failed to receive channel monitor pipe");
1133                         goto error_fatal;
1134                 }
1135
1136                 DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
1137                 ret_set_channel_monitor_pipe =
1138                                 consumer_timer_thread_set_channel_monitor_pipe(
1139                                                 channel_monitor_pipe);
1140                 if (!ret_set_channel_monitor_pipe) {
1141                         int flags;
1142                         int ret_fcntl;
1143
1144                         ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1145                         /* Set the pipe as non-blocking. */
1146                         ret_fcntl = fcntl(channel_monitor_pipe, F_GETFL, 0);
1147                         if (ret_fcntl == -1) {
1148                                 PERROR("fcntl get flags of the channel monitoring pipe");
1149                                 goto error_fatal;
1150                         }
1151                         flags = ret_fcntl;
1152
1153                         ret_fcntl = fcntl(channel_monitor_pipe, F_SETFL,
1154                                         flags | O_NONBLOCK);
1155                         if (ret_fcntl == -1) {
1156                                 PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
1157                                 goto error_fatal;
1158                         }
1159                         DBG("Channel monitor pipe set as non-blocking");
1160                 } else {
1161                         ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
1162                 }
1163                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1164                 if (ret_send_status < 0) {
1165                         goto error_fatal;
1166                 }
1167                 break;
1168         }
1169         case LTTNG_CONSUMER_ROTATE_CHANNEL:
1170         {
1171                 struct lttng_consumer_channel *channel;
1172                 uint64_t key = msg.u.rotate_channel.key;
1173                 int ret_send_status;
1174
1175                 DBG("Consumer rotate channel %" PRIu64, key);
1176
1177                 channel = consumer_find_channel(key);
1178                 if (!channel) {
1179                         ERR("Channel %" PRIu64 " not found", key);
1180                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1181                 } else {
1182                         /*
1183                          * Sample the rotate position of all the streams in this channel.
1184                          */
1185                         int ret_rotate_channel;
1186
1187                         ret_rotate_channel = lttng_consumer_rotate_channel(
1188                                         channel, key,
1189                                         msg.u.rotate_channel.relayd_id,
1190                                         msg.u.rotate_channel.metadata, ctx);
1191                         if (ret_rotate_channel < 0) {
1192                                 ERR("Rotate channel failed");
1193                                 ret_code = LTTCOMM_CONSUMERD_ROTATION_FAIL;
1194                         }
1195
1196                         health_code_update();
1197                 }
1198
1199                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1200                 if (ret_send_status < 0) {
1201                         /* Somehow, the session daemon is not responding anymore. */
1202                         goto error_rotate_channel;
1203                 }
1204                 if (channel) {
1205                         /* Rotate the streams that are ready right now. */
1206                         int ret_rotate;
1207
1208                         ret_rotate = lttng_consumer_rotate_ready_streams(
1209                                         channel, key, ctx);
1210                         if (ret_rotate < 0) {
1211                                 ERR("Rotate ready streams failed");
1212                         }
1213                 }
1214                 break;
1215 error_rotate_channel:
1216                 goto end_nosignal;
1217         }
1218         case LTTNG_CONSUMER_CLEAR_CHANNEL:
1219         {
1220                 struct lttng_consumer_channel *channel;
1221                 uint64_t key = msg.u.clear_channel.key;
1222                 int ret_send_status;
1223
1224                 channel = consumer_find_channel(key);
1225                 if (!channel) {
1226                         DBG("Channel %" PRIu64 " not found", key);
1227                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1228                 } else {
1229                         int ret_clear_channel;
1230
1231                         ret_clear_channel =
1232                                         lttng_consumer_clear_channel(channel);
1233                         if (ret_clear_channel) {
1234                                 ERR("Clear channel failed");
1235                                 ret_code = ret_clear_channel;
1236                         }
1237
1238                         health_code_update();
1239                 }
1240
1241                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1242                 if (ret_send_status < 0) {
1243                         /* Somehow, the session daemon is not responding anymore. */
1244                         goto end_nosignal;
1245                 }
1246
1247                 break;
1248         }
1249         case LTTNG_CONSUMER_INIT:
1250         {
1251                 int ret_send_status;
1252
1253                 ret_code = lttng_consumer_init_command(ctx,
1254                                 msg.u.init.sessiond_uuid);
1255                 health_code_update();
1256                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1257                 if (ret_send_status < 0) {
1258                         /* Somehow, the session daemon is not responding anymore. */
1259                         goto end_nosignal;
1260                 }
1261                 break;
1262         }
1263         case LTTNG_CONSUMER_CREATE_TRACE_CHUNK:
1264         {
1265                 const struct lttng_credentials credentials = {
1266                         .uid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.uid),
1267                         .gid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.gid),
1268                 };
1269                 const bool is_local_trace =
1270                                 !msg.u.create_trace_chunk.relayd_id.is_set;
1271                 const uint64_t relayd_id =
1272                                 msg.u.create_trace_chunk.relayd_id.value;
1273                 const char *chunk_override_name =
1274                                 *msg.u.create_trace_chunk.override_name ?
1275                                         msg.u.create_trace_chunk.override_name :
1276                                         NULL;
1277                 struct lttng_directory_handle *chunk_directory_handle = NULL;
1278
1279                 /*
1280                  * The session daemon will only provide a chunk directory file
1281                  * descriptor for local traces.
1282                  */
1283                 if (is_local_trace) {
1284                         int chunk_dirfd;
1285                         int ret_send_status;
1286                         ssize_t ret_recv;
1287
1288                         /* Acnowledge the reception of the command. */
1289                         ret_send_status = consumer_send_status_msg(
1290                                         sock, LTTCOMM_CONSUMERD_SUCCESS);
1291                         if (ret_send_status < 0) {
1292                                 /* Somehow, the session daemon is not responding anymore. */
1293                                 goto end_nosignal;
1294                         }
1295
1296                         ret_recv = lttcomm_recv_fds_unix_sock(
1297                                         sock, &chunk_dirfd, 1);
1298                         if (ret_recv != sizeof(chunk_dirfd)) {
1299                                 ERR("Failed to receive trace chunk directory file descriptor");
1300                                 goto error_fatal;
1301                         }
1302
1303                         DBG("Received trace chunk directory fd (%d)",
1304                                         chunk_dirfd);
1305                         chunk_directory_handle = lttng_directory_handle_create_from_dirfd(
1306                                         chunk_dirfd);
1307                         if (!chunk_directory_handle) {
1308                                 ERR("Failed to initialize chunk directory handle from directory file descriptor");
1309                                 if (close(chunk_dirfd)) {
1310                                         PERROR("Failed to close chunk directory file descriptor");
1311                                 }
1312                                 goto error_fatal;
1313                         }
1314                 }
1315
1316                 ret_code = lttng_consumer_create_trace_chunk(
1317                                 !is_local_trace ? &relayd_id : NULL,
1318                                 msg.u.create_trace_chunk.session_id,
1319                                 msg.u.create_trace_chunk.chunk_id,
1320                                 (time_t) msg.u.create_trace_chunk
1321                                                 .creation_timestamp,
1322                                 chunk_override_name,
1323                                 msg.u.create_trace_chunk.credentials.is_set ?
1324                                                 &credentials :
1325                                                 NULL,
1326                                 chunk_directory_handle);
1327                 lttng_directory_handle_put(chunk_directory_handle);
1328                 goto end_msg_sessiond;
1329         }
1330         case LTTNG_CONSUMER_CLOSE_TRACE_CHUNK:
1331         {
1332                 enum lttng_trace_chunk_command_type close_command =
1333                                 msg.u.close_trace_chunk.close_command.value;
1334                 const uint64_t relayd_id =
1335                                 msg.u.close_trace_chunk.relayd_id.value;
1336                 struct lttcomm_consumer_close_trace_chunk_reply reply;
1337                 char path[LTTNG_PATH_MAX];
1338                 ssize_t ret_send;
1339
1340                 ret_code = lttng_consumer_close_trace_chunk(
1341                                 msg.u.close_trace_chunk.relayd_id.is_set ?
1342                                                 &relayd_id :
1343                                                 NULL,
1344                                 msg.u.close_trace_chunk.session_id,
1345                                 msg.u.close_trace_chunk.chunk_id,
1346                                 (time_t) msg.u.close_trace_chunk.close_timestamp,
1347                                 msg.u.close_trace_chunk.close_command.is_set ?
1348                                                 &close_command :
1349                                                 NULL, path);
1350                 reply.ret_code = ret_code;
1351                 reply.path_length = strlen(path) + 1;
1352                 ret_send = lttcomm_send_unix_sock(sock, &reply, sizeof(reply));
1353                 if (ret_send != sizeof(reply)) {
1354                         goto error_fatal;
1355                 }
1356                 ret_send = lttcomm_send_unix_sock(
1357                                 sock, path, reply.path_length);
1358                 if (ret_send != reply.path_length) {
1359                         goto error_fatal;
1360                 }
1361                 goto end_nosignal;
1362         }
1363         case LTTNG_CONSUMER_TRACE_CHUNK_EXISTS:
1364         {
1365                 const uint64_t relayd_id =
1366                                 msg.u.trace_chunk_exists.relayd_id.value;
1367
1368                 ret_code = lttng_consumer_trace_chunk_exists(
1369                                 msg.u.trace_chunk_exists.relayd_id.is_set ?
1370                                                 &relayd_id : NULL,
1371                                 msg.u.trace_chunk_exists.session_id,
1372                                 msg.u.trace_chunk_exists.chunk_id);
1373                 goto end_msg_sessiond;
1374         }
1375         case LTTNG_CONSUMER_OPEN_CHANNEL_PACKETS:
1376         {
1377                 const uint64_t key = msg.u.open_channel_packets.key;
1378                 struct lttng_consumer_channel *channel =
1379                                 consumer_find_channel(key);
1380
1381                 if (channel) {
1382                         pthread_mutex_lock(&channel->lock);
1383                         ret_code = lttng_consumer_open_channel_packets(channel);
1384                         pthread_mutex_unlock(&channel->lock);
1385                 } else {
1386                         WARN("Channel %" PRIu64 " not found", key);
1387                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1388                 }
1389
1390                 health_code_update();
1391                 goto end_msg_sessiond;
1392         }
1393         default:
1394                 goto end_nosignal;
1395         }
1396
1397 end_nosignal:
1398         /*
1399          * Return 1 to indicate success since the 0 value can be a socket
1400          * shutdown during the recv() or send() call.
1401          */
1402         ret_func = 1;
1403         goto end;
1404 error_fatal:
1405         /* This will issue a consumer stop. */
1406         ret_func = -1;
1407         goto end;
1408 end_msg_sessiond:
1409         /*
1410          * The returned value here is not useful since either way we'll return 1 to
1411          * the caller because the session daemon socket management is done
1412          * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1413          */
1414         {
1415                 int ret_send_status;
1416
1417                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1418                 if (ret_send_status < 0) {
1419                         goto error_fatal;
1420                 }
1421         }
1422
1423         ret_func = 1;
1424
1425 end:
1426         health_code_update();
1427         rcu_read_unlock();
1428         return ret_func;
1429 }
1430
1431 /*
1432  * Sync metadata meaning request them to the session daemon and snapshot to the
1433  * metadata thread can consumer them.
1434  *
1435  * Metadata stream lock MUST be acquired.
1436  */
1437 enum sync_metadata_status lttng_kconsumer_sync_metadata(
1438                 struct lttng_consumer_stream *metadata)
1439 {
1440         int ret;
1441         enum sync_metadata_status status;
1442
1443         assert(metadata);
1444
1445         ret = kernctl_buffer_flush(metadata->wait_fd);
1446         if (ret < 0) {
1447                 ERR("Failed to flush kernel stream");
1448                 status = SYNC_METADATA_STATUS_ERROR;
1449                 goto end;
1450         }
1451
1452         ret = kernctl_snapshot(metadata->wait_fd);
1453         if (ret < 0) {
1454                 if (errno == EAGAIN) {
1455                         /* No new metadata, exit. */
1456                         DBG("Sync metadata, no new kernel metadata");
1457                         status = SYNC_METADATA_STATUS_NO_DATA;
1458                 } else {
1459                         ERR("Sync metadata, taking kernel snapshot failed.");
1460                         status = SYNC_METADATA_STATUS_ERROR;
1461                 }
1462         } else {
1463                 status = SYNC_METADATA_STATUS_NEW_DATA;
1464         }
1465
1466 end:
1467         return status;
1468 }
1469
1470 static
1471 int extract_common_subbuffer_info(struct lttng_consumer_stream *stream,
1472                 struct stream_subbuffer *subbuf)
1473 {
1474         int ret;
1475
1476         ret = kernctl_get_subbuf_size(
1477                         stream->wait_fd, &subbuf->info.data.subbuf_size);
1478         if (ret) {
1479                 goto end;
1480         }
1481
1482         ret = kernctl_get_padded_subbuf_size(
1483                         stream->wait_fd, &subbuf->info.data.padded_subbuf_size);
1484         if (ret) {
1485                 goto end;
1486         }
1487
1488 end:
1489         return ret;
1490 }
1491
1492 static
1493 int extract_metadata_subbuffer_info(struct lttng_consumer_stream *stream,
1494                 struct stream_subbuffer *subbuf)
1495 {
1496         int ret;
1497
1498         ret = extract_common_subbuffer_info(stream, subbuf);
1499         if (ret) {
1500                 goto end;
1501         }
1502
1503         ret = kernctl_get_metadata_version(
1504                         stream->wait_fd, &subbuf->info.metadata.version);
1505         if (ret) {
1506                 goto end;
1507         }
1508
1509 end:
1510         return ret;
1511 }
1512
1513 static
1514 int extract_data_subbuffer_info(struct lttng_consumer_stream *stream,
1515                 struct stream_subbuffer *subbuf)
1516 {
1517         int ret;
1518
1519         ret = extract_common_subbuffer_info(stream, subbuf);
1520         if (ret) {
1521                 goto end;
1522         }
1523
1524         ret = kernctl_get_packet_size(
1525                         stream->wait_fd, &subbuf->info.data.packet_size);
1526         if (ret < 0) {
1527                 PERROR("Failed to get sub-buffer packet size");
1528                 goto end;
1529         }
1530
1531         ret = kernctl_get_content_size(
1532                         stream->wait_fd, &subbuf->info.data.content_size);
1533         if (ret < 0) {
1534                 PERROR("Failed to get sub-buffer content size");
1535                 goto end;
1536         }
1537
1538         ret = kernctl_get_timestamp_begin(
1539                         stream->wait_fd, &subbuf->info.data.timestamp_begin);
1540         if (ret < 0) {
1541                 PERROR("Failed to get sub-buffer begin timestamp");
1542                 goto end;
1543         }
1544
1545         ret = kernctl_get_timestamp_end(
1546                         stream->wait_fd, &subbuf->info.data.timestamp_end);
1547         if (ret < 0) {
1548                 PERROR("Failed to get sub-buffer end timestamp");
1549                 goto end;
1550         }
1551
1552         ret = kernctl_get_events_discarded(
1553                         stream->wait_fd, &subbuf->info.data.events_discarded);
1554         if (ret) {
1555                 PERROR("Failed to get sub-buffer events discarded count");
1556                 goto end;
1557         }
1558
1559         ret = kernctl_get_sequence_number(stream->wait_fd,
1560                         &subbuf->info.data.sequence_number.value);
1561         if (ret) {
1562                 /* May not be supported by older LTTng-modules. */
1563                 if (ret != -ENOTTY) {
1564                         PERROR("Failed to get sub-buffer sequence number");
1565                         goto end;
1566                 }
1567         } else {
1568                 subbuf->info.data.sequence_number.is_set = true;
1569         }
1570
1571         ret = kernctl_get_stream_id(
1572                         stream->wait_fd, &subbuf->info.data.stream_id);
1573         if (ret < 0) {
1574                 PERROR("Failed to get stream id");
1575                 goto end;
1576         }
1577
1578         ret = kernctl_get_instance_id(stream->wait_fd,
1579                         &subbuf->info.data.stream_instance_id.value);
1580         if (ret) {
1581                 /* May not be supported by older LTTng-modules. */
1582                 if (ret != -ENOTTY) {
1583                         PERROR("Failed to get stream instance id");
1584                         goto end;
1585                 }
1586         } else {
1587                 subbuf->info.data.stream_instance_id.is_set = true;
1588         }
1589 end:
1590         return ret;
1591 }
1592
1593 static
1594 enum get_next_subbuffer_status get_subbuffer_common(
1595                 struct lttng_consumer_stream *stream,
1596                 struct stream_subbuffer *subbuffer)
1597 {
1598         int ret;
1599         enum get_next_subbuffer_status status;
1600
1601         ret = kernctl_get_next_subbuf(stream->wait_fd);
1602         switch (ret) {
1603         case 0:
1604                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1605                 break;
1606         case -ENODATA:
1607                 case -EAGAIN:
1608                 /*
1609                  * The caller only expects -ENODATA when there is no data to
1610                  * read, but the kernel tracer returns -EAGAIN when there is
1611                  * currently no data for a non-finalized stream, and -ENODATA
1612                  * when there is no data for a finalized stream. Those can be
1613                  * combined into a -ENODATA return value.
1614                  */
1615                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1616                 goto end;
1617         default:
1618                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1619                 goto end;
1620         }
1621
1622         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1623                 stream, subbuffer);
1624         if (ret) {
1625                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1626         }
1627 end:
1628         return status;
1629 }
1630
1631 static
1632 enum get_next_subbuffer_status get_next_subbuffer_splice(
1633                 struct lttng_consumer_stream *stream,
1634                 struct stream_subbuffer *subbuffer)
1635 {
1636         const enum get_next_subbuffer_status status =
1637                         get_subbuffer_common(stream, subbuffer);
1638
1639         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1640                 goto end;
1641         }
1642
1643         subbuffer->buffer.fd = stream->wait_fd;
1644 end:
1645         return status;
1646 }
1647
1648 static
1649 enum get_next_subbuffer_status get_next_subbuffer_mmap(
1650                 struct lttng_consumer_stream *stream,
1651                 struct stream_subbuffer *subbuffer)
1652 {
1653         int ret;
1654         enum get_next_subbuffer_status status;
1655         const char *addr;
1656
1657         status = get_subbuffer_common(stream, subbuffer);
1658         if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
1659                 goto end;
1660         }
1661
1662         ret = get_current_subbuf_addr(stream, &addr);
1663         if (ret) {
1664                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1665                 goto end;
1666         }
1667
1668         subbuffer->buffer.buffer = lttng_buffer_view_init(
1669                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1670 end:
1671         return status;
1672 }
1673
1674 static
1675 enum get_next_subbuffer_status get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
1676                 struct stream_subbuffer *subbuffer)
1677 {
1678         int ret;
1679         const char *addr;
1680         bool coherent;
1681         enum get_next_subbuffer_status status;
1682
1683         ret = kernctl_get_next_subbuf_metadata_check(stream->wait_fd,
1684                         &coherent);
1685         if (ret) {
1686                 goto end;
1687         }
1688
1689         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1690                         stream, subbuffer);
1691         if (ret) {
1692                 goto end;
1693         }
1694
1695         LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
1696
1697         ret = get_current_subbuf_addr(stream, &addr);
1698         if (ret) {
1699                 goto end;
1700         }
1701
1702         subbuffer->buffer.buffer = lttng_buffer_view_init(
1703                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1704         DBG("Got metadata packet with padded_subbuf_size = %lu, coherent = %s",
1705                         subbuffer->info.metadata.padded_subbuf_size,
1706                         coherent ? "true" : "false");
1707 end:
1708         /*
1709          * The caller only expects -ENODATA when there is no data to read, but
1710          * the kernel tracer returns -EAGAIN when there is currently no data
1711          * for a non-finalized stream, and -ENODATA when there is no data for a
1712          * finalized stream. Those can be combined into a -ENODATA return value.
1713          */
1714         switch (ret) {
1715         case 0:
1716                 status = GET_NEXT_SUBBUFFER_STATUS_OK;
1717                 break;
1718         case -ENODATA:
1719         case -EAGAIN:
1720                 /*
1721                  * The caller only expects -ENODATA when there is no data to
1722                  * read, but the kernel tracer returns -EAGAIN when there is
1723                  * currently no data for a non-finalized stream, and -ENODATA
1724                  * when there is no data for a finalized stream. Those can be
1725                  * combined into a -ENODATA return value.
1726                  */
1727                 status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
1728                 break;
1729         default:
1730                 status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
1731                 break;
1732         }
1733
1734         return status;
1735 }
1736
1737 static
1738 int put_next_subbuffer(struct lttng_consumer_stream *stream,
1739                 struct stream_subbuffer *subbuffer)
1740 {
1741         const int ret = kernctl_put_next_subbuf(stream->wait_fd);
1742
1743         if (ret) {
1744                 if (ret == -EFAULT) {
1745                         PERROR("Error in unreserving sub buffer");
1746                 } else if (ret == -EIO) {
1747                         /* Should never happen with newer LTTng versions */
1748                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted");
1749                 }
1750         }
1751
1752         return ret;
1753 }
1754
1755 static
1756 bool is_get_next_check_metadata_available(int tracer_fd)
1757 {
1758         const int ret = kernctl_get_next_subbuf_metadata_check(tracer_fd, NULL);
1759         const bool available = ret != -ENOTTY;
1760
1761         if (ret == 0) {
1762                 /* get succeeded, make sure to put the subbuffer. */
1763                 kernctl_put_subbuf(tracer_fd);
1764         }
1765
1766         return available;
1767 }
1768
1769 static
1770 int signal_metadata(struct lttng_consumer_stream *stream,
1771                 struct lttng_consumer_local_data *ctx)
1772 {
1773         ASSERT_LOCKED(stream->metadata_rdv_lock);
1774         return pthread_cond_broadcast(&stream->metadata_rdv) ? -errno : 0;
1775 }
1776
1777 static
1778 int lttng_kconsumer_set_stream_ops(
1779                 struct lttng_consumer_stream *stream)
1780 {
1781         int ret = 0;
1782
1783         if (stream->metadata_flag && stream->chan->is_live) {
1784                 DBG("Attempting to enable metadata bucketization for live consumers");
1785                 if (is_get_next_check_metadata_available(stream->wait_fd)) {
1786                         DBG("Kernel tracer supports get_next_subbuffer_metadata_check, metadata will be accumulated until a coherent state is reached");
1787                         stream->read_subbuffer_ops.get_next_subbuffer =
1788                                         get_next_subbuffer_metadata_check;
1789                         ret = consumer_stream_enable_metadata_bucketization(
1790                                         stream);
1791                         if (ret) {
1792                                 goto end;
1793                         }
1794                 } else {
1795                         /*
1796                          * The kernel tracer version is too old to indicate
1797                          * when the metadata stream has reached a "coherent"
1798                          * (parseable) point.
1799                          *
1800                          * This means that a live viewer may see an incoherent
1801                          * sequence of metadata and fail to parse it.
1802                          */
1803                         WARN("Kernel tracer does not support get_next_subbuffer_metadata_check which may cause live clients to fail to parse the metadata stream");
1804                         metadata_bucket_destroy(stream->metadata_bucket);
1805                         stream->metadata_bucket = NULL;
1806                 }
1807
1808                 stream->read_subbuffer_ops.on_sleep = signal_metadata;
1809         }
1810
1811         if (!stream->read_subbuffer_ops.get_next_subbuffer) {
1812                 if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
1813                         stream->read_subbuffer_ops.get_next_subbuffer =
1814                                         get_next_subbuffer_mmap;
1815                 } else {
1816                         stream->read_subbuffer_ops.get_next_subbuffer =
1817                                         get_next_subbuffer_splice;
1818                 }
1819         }
1820
1821         if (stream->metadata_flag) {
1822                 stream->read_subbuffer_ops.extract_subbuffer_info =
1823                                 extract_metadata_subbuffer_info;
1824         } else {
1825                 stream->read_subbuffer_ops.extract_subbuffer_info =
1826                                 extract_data_subbuffer_info;
1827                 if (stream->chan->is_live) {
1828                         stream->read_subbuffer_ops.send_live_beacon =
1829                                         consumer_flush_kernel_index;
1830                 }
1831         }
1832
1833         stream->read_subbuffer_ops.put_next_subbuffer = put_next_subbuffer;
1834 end:
1835         return ret;
1836 }
1837
1838 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1839 {
1840         int ret;
1841
1842         assert(stream);
1843
1844         /*
1845          * Don't create anything if this is set for streaming or if there is
1846          * no current trace chunk on the parent channel.
1847          */
1848         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor &&
1849                         stream->chan->trace_chunk) {
1850                 ret = consumer_stream_create_output_files(stream, true);
1851                 if (ret) {
1852                         goto error;
1853                 }
1854         }
1855
1856         if (stream->output == LTTNG_EVENT_MMAP) {
1857                 /* get the len of the mmap region */
1858                 unsigned long mmap_len;
1859
1860                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1861                 if (ret != 0) {
1862                         PERROR("kernctl_get_mmap_len");
1863                         goto error_close_fd;
1864                 }
1865                 stream->mmap_len = (size_t) mmap_len;
1866
1867                 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
1868                                 MAP_PRIVATE, stream->wait_fd, 0);
1869                 if (stream->mmap_base == MAP_FAILED) {
1870                         PERROR("Error mmaping");
1871                         ret = -1;
1872                         goto error_close_fd;
1873                 }
1874         }
1875
1876         ret = lttng_kconsumer_set_stream_ops(stream);
1877         if (ret) {
1878                 goto error_close_fd;
1879         }
1880
1881         /* we return 0 to let the library handle the FD internally */
1882         return 0;
1883
1884 error_close_fd:
1885         if (stream->out_fd >= 0) {
1886                 int err;
1887
1888                 err = close(stream->out_fd);
1889                 assert(!err);
1890                 stream->out_fd = -1;
1891         }
1892 error:
1893         return ret;
1894 }
1895
1896 /*
1897  * Check if data is still being extracted from the buffers for a specific
1898  * stream. Consumer data lock MUST be acquired before calling this function
1899  * and the stream lock.
1900  *
1901  * Return 1 if the traced data are still getting read else 0 meaning that the
1902  * data is available for trace viewer reading.
1903  */
1904 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1905 {
1906         int ret;
1907
1908         assert(stream);
1909
1910         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1911                 ret = 0;
1912                 goto end;
1913         }
1914
1915         ret = kernctl_get_next_subbuf(stream->wait_fd);
1916         if (ret == 0) {
1917                 /* There is still data so let's put back this subbuffer. */
1918                 ret = kernctl_put_subbuf(stream->wait_fd);
1919                 assert(ret == 0);
1920                 ret = 1;   /* Data is pending */
1921                 goto end;
1922         }
1923
1924         /* Data is NOT pending and ready to be read. */
1925         ret = 0;
1926
1927 end:
1928         return ret;
1929 }