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