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

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