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                         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         int ret_func;
 455         enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 456         struct lttcomm_consumer_msg msg;
 457
 458         health_code_update();
 459
 460         {
 461                 ssize_t ret_recv;
 462
 463                 ret_recv = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 464                 if (ret_recv != sizeof(msg)) {
 465                         if (ret_recv > 0) {
 466                                 lttng_consumer_send_error(ctx,
 467                                                 LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 468                                 ret_recv = -1;
 469                         }
 470                         return ret_recv;
 471                 }
 472         }
 473
 474         health_code_update();
 475
 476         /* Deprecated command */
 477         assert(msg.cmd_type != LTTNG_CONSUMER_STOP);
 478
 479         health_code_update();
 480
 481         /* relayd needs RCU read-side protection */
 482         rcu_read_lock();
 483
 484         switch (msg.cmd_type) {
 485         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 486         {
 487                 /* Session daemon status message are handled in the following call. */
 488                 consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 489                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 490                                 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
 491                                 msg.u.relayd_sock.relayd_session_id);
 492                 goto end_nosignal;
 493         }
 494         case LTTNG_CONSUMER_ADD_CHANNEL:
 495         {
 496                 struct lttng_consumer_channel *new_channel;
 497                 int ret_send_status, ret_add_channel = 0;
 498                 const uint64_t chunk_id = msg.u.channel.chunk_id.value;
 499
 500                 health_code_update();
 501
 502                 /* First send a status message before receiving the fds. */
 503                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 504                 if (ret_send_status < 0) {
 505                         /* Somehow, the session daemon is not responding anymore. */
 506                         goto error_fatal;
 507                 }
 508
 509                 health_code_update();
 510
 511                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 512                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 513                                 msg.u.channel.session_id,
 514                                 msg.u.channel.chunk_id.is_set ?
 515                                                 &chunk_id : NULL,
 516                                 msg.u.channel.pathname,
 517                                 msg.u.channel.name,
 518                                 msg.u.channel.relayd_id, msg.u.channel.output,
 519                                 msg.u.channel.tracefile_size,
 520                                 msg.u.channel.tracefile_count, 0,
 521                                 msg.u.channel.monitor,
 522                                 msg.u.channel.live_timer_interval,
 523                                 msg.u.channel.is_live,
 524                                 NULL, NULL);
 525                 if (new_channel == NULL) {
 526                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 527                         goto end_nosignal;
 528                 }
 529                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 530                 switch (msg.u.channel.output) {
 531                 case LTTNG_EVENT_SPLICE:
 532                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 533                         break;
 534                 case LTTNG_EVENT_MMAP:
 535                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 536                         break;
 537                 default:
 538                         ERR("Channel output unknown %d", msg.u.channel.output);
 539                         goto end_nosignal;
 540                 }
 541
 542                 /* Translate and save channel type. */
 543                 switch (msg.u.channel.type) {
 544                 case CONSUMER_CHANNEL_TYPE_DATA:
 545                 case CONSUMER_CHANNEL_TYPE_METADATA:
 546                         new_channel->type = msg.u.channel.type;
 547                         break;
 548                 default:
 549                         assert(0);
 550                         goto end_nosignal;
 551                 };
 552
 553                 health_code_update();
 554
 555                 if (ctx->on_recv_channel != NULL) {
 556                         int ret_recv_channel =
 557                                         ctx->on_recv_channel(new_channel);
 558                         if (ret_recv_channel == 0) {
 559                                 ret_add_channel = consumer_add_channel(
 560                                                 new_channel, ctx);
 561                         } else if (ret_recv_channel < 0) {
 562                                 goto end_nosignal;
 563                         }
 564                 } else {
 565                         ret_add_channel =
 566                                         consumer_add_channel(new_channel, ctx);
 567                 }
 568                 if (msg.u.channel.type == CONSUMER_CHANNEL_TYPE_DATA &&
 569                                 !ret_add_channel) {
 570                         int monitor_start_ret;
 571
 572                         DBG("Consumer starting monitor timer");
 573                         consumer_timer_live_start(new_channel,
 574                                         msg.u.channel.live_timer_interval);
 575                         monitor_start_ret = consumer_timer_monitor_start(
 576                                         new_channel,
 577                                         msg.u.channel.monitor_timer_interval);
 578                         if (monitor_start_ret < 0) {
 579                                 ERR("Starting channel monitoring timer failed");
 580                                 goto end_nosignal;
 581                         }
 582                 }
 583
 584                 health_code_update();
 585
 586                 /* If we received an error in add_channel, we need to report it. */
 587                 if (ret_add_channel < 0) {
 588                         ret_send_status = consumer_send_status_msg(
 589                                         sock, ret_add_channel);
 590                         if (ret_send_status < 0) {
 591                                 goto error_fatal;
 592                         }
 593                         goto end_nosignal;
 594                 }
 595
 596                 goto end_nosignal;
 597         }
 598         case LTTNG_CONSUMER_ADD_STREAM:
 599         {
 600                 int fd;
 601                 struct lttng_pipe *stream_pipe;
 602                 struct lttng_consumer_stream *new_stream;
 603                 struct lttng_consumer_channel *channel;
 604                 int alloc_ret = 0;
 605                 int ret_send_status, ret_poll, ret_get_max_subbuf_size;
 606                 ssize_t ret_pipe_write, ret_recv;
 607
 608                 /*
 609                  * Get stream's channel reference. Needed when adding the stream to the
 610                  * global hash table.
 611                  */
 612                 channel = consumer_find_channel(msg.u.stream.channel_key);
 613                 if (!channel) {
 614                         /*
 615                          * We could not find the channel. Can happen if cpu hotplug
 616                          * happens while tearing down.
 617                          */
 618                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 619                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 620                 }
 621
 622                 health_code_update();
 623
 624                 /* First send a status message before receiving the fds. */
 625                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 626                 if (ret_send_status < 0) {
 627                         /* Somehow, the session daemon is not responding anymore. */
 628                         goto error_add_stream_fatal;
 629                 }
 630
 631                 health_code_update();
 632
 633                 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 634                         /* Channel was not found. */
 635                         goto error_add_stream_nosignal;
 636                 }
 637
 638                 /* Blocking call */
 639                 health_poll_entry();
 640                 ret_poll = lttng_consumer_poll_socket(consumer_sockpoll);
 641                 health_poll_exit();
 642                 if (ret_poll) {
 643                         goto error_add_stream_fatal;
 644                 }
 645
 646                 health_code_update();
 647
 648                 /* Get stream file descriptor from socket */
 649                 ret_recv = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 650                 if (ret_recv != sizeof(fd)) {
 651                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 652                         ret_func = ret_recv;
 653                         goto end;
 654                 }
 655
 656                 health_code_update();
 657
 658                 /*
 659                  * Send status code to session daemon only if the recv works. If the
 660                  * above recv() failed, the session daemon is notified through the
 661                  * error socket and the teardown is eventually done.
 662                  */
 663                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 664                 if (ret_send_status < 0) {
 665                         /* Somehow, the session daemon is not responding anymore. */
 666                         goto error_add_stream_nosignal;
 667                 }
 668
 669                 health_code_update();
 670
 671                 pthread_mutex_lock(&channel->lock);
 672                 new_stream = consumer_stream_create(
 673                                 channel,
 674                                 channel->key,
 675                                 fd,
 676                                 channel->name,
 677                                 channel->relayd_id,
 678                                 channel->session_id,
 679                                 channel->trace_chunk,
 680                                 msg.u.stream.cpu,
 681                                 &alloc_ret,
 682                                 channel->type,
 683                                 channel->monitor);
 684                 if (new_stream == NULL) {
 685                         switch (alloc_ret) {
 686                         case -ENOMEM:
 687                         case -EINVAL:
 688                         default:
 689                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 690                                 break;
 691                         }
 692                         pthread_mutex_unlock(&channel->lock);
 693                         goto error_add_stream_nosignal;
 694                 }
 695
 696                 new_stream->wait_fd = fd;
 697                 ret_get_max_subbuf_size = kernctl_get_max_subbuf_size(
 698                                 new_stream->wait_fd, &new_stream->max_sb_size);
 699                 if (ret_get_max_subbuf_size < 0) {
 700                         pthread_mutex_unlock(&channel->lock);
 701                         ERR("Failed to get kernel maximal subbuffer size");
 702                         goto error_add_stream_nosignal;
 703                 }
 704
 705                 consumer_stream_update_channel_attributes(new_stream,
 706                                 channel);
 707
 708                 /*
 709                  * We've just assigned the channel to the stream so increment the
 710                  * refcount right now. We don't need to increment the refcount for
 711                  * streams in no monitor because we handle manually the cleanup of
 712                  * those. It is very important to make sure there is NO prior
 713                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 714                  */
 715                 if (channel->monitor) {
 716                         uatomic_inc(&new_stream->chan->refcount);
 717                 }
 718
 719                 /*
 720                  * The buffer flush is done on the session daemon side for the kernel
 721                  * so no need for the stream "hangup_flush_done" variable to be
 722                  * tracked. This is important for a kernel stream since we don't rely
 723                  * on the flush state of the stream to read data. It's not the case for
 724                  * user space tracing.
 725                  */
 726                 new_stream->hangup_flush_done = 0;
 727
 728                 health_code_update();
 729
 730                 pthread_mutex_lock(&new_stream->lock);
 731                 if (ctx->on_recv_stream) {
 732                         int ret_recv_stream = ctx->on_recv_stream(new_stream);
 733                         if (ret_recv_stream < 0) {
 734                                 pthread_mutex_unlock(&new_stream->lock);
 735                                 pthread_mutex_unlock(&channel->lock);
 736                                 consumer_stream_free(new_stream);
 737                                 goto error_add_stream_nosignal;
 738                         }
 739                 }
 740                 health_code_update();
 741
 742                 if (new_stream->metadata_flag) {
 743                         channel->metadata_stream = new_stream;
 744                 }
 745
 746                 /* Do not monitor this stream. */
 747                 if (!channel->monitor) {
 748                         DBG("Kernel consumer add stream %s in no monitor mode with "
 749                                         "relayd id %" PRIu64, new_stream->name,
 750                                         new_stream->net_seq_idx);
 751                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 752                         pthread_mutex_unlock(&new_stream->lock);
 753                         pthread_mutex_unlock(&channel->lock);
 754                         goto end_add_stream;
 755                 }
 756
 757                 /* Send stream to relayd if the stream has an ID. */
 758                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 759                         int ret_send_relayd_stream;
 760
 761                         ret_send_relayd_stream = consumer_send_relayd_stream(
 762                                         new_stream, new_stream->chan->pathname);
 763                         if (ret_send_relayd_stream < 0) {
 764                                 pthread_mutex_unlock(&new_stream->lock);
 765                                 pthread_mutex_unlock(&channel->lock);
 766                                 consumer_stream_free(new_stream);
 767                                 goto error_add_stream_nosignal;
 768                         }
 769
 770                         /*
 771                          * If adding an extra stream to an already
 772                          * existing channel (e.g. cpu hotplug), we need
 773                          * to send the "streams_sent" command to relayd.
 774                          */
 775                         if (channel->streams_sent_to_relayd) {
 776                                 int ret_send_relayd_streams_sent;
 777
 778                                 ret_send_relayd_streams_sent =
 779                                                 consumer_send_relayd_streams_sent(
 780                                                                 new_stream->net_seq_idx);
 781                                 if (ret_send_relayd_streams_sent < 0) {
 782                                         pthread_mutex_unlock(&new_stream->lock);
 783                                         pthread_mutex_unlock(&channel->lock);
 784                                         goto error_add_stream_nosignal;
 785                                 }
 786                         }
 787                 }
 788                 pthread_mutex_unlock(&new_stream->lock);
 789                 pthread_mutex_unlock(&channel->lock);
 790
 791                 /* Get the right pipe where the stream will be sent. */
 792                 if (new_stream->metadata_flag) {
 793                         consumer_add_metadata_stream(new_stream);
 794                         stream_pipe = ctx->consumer_metadata_pipe;
 795                 } else {
 796                         consumer_add_data_stream(new_stream);
 797                         stream_pipe = ctx->consumer_data_pipe;
 798                 }
 799
 800                 /* Visible to other threads */
 801                 new_stream->globally_visible = 1;
 802
 803                 health_code_update();
 804
 805                 ret_pipe_write = lttng_pipe_write(
 806                                 stream_pipe, &new_stream, sizeof(new_stream));
 807                 if (ret_pipe_write < 0) {
 808                         ERR("Consumer write %s stream to pipe %d",
 809                                         new_stream->metadata_flag ? "metadata" : "data",
 810                                         lttng_pipe_get_writefd(stream_pipe));
 811                         if (new_stream->metadata_flag) {
 812                                 consumer_del_stream_for_metadata(new_stream);
 813                         } else {
 814                                 consumer_del_stream_for_data(new_stream);
 815                         }
 816                         goto error_add_stream_nosignal;
 817                 }
 818
 819                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
 820                                 new_stream->name, fd, new_stream->chan->pathname, new_stream->relayd_stream_id);
 821 end_add_stream:
 822                 break;
 823 error_add_stream_nosignal:
 824                 goto end_nosignal;
 825 error_add_stream_fatal:
 826                 goto error_fatal;
 827         }
 828         case LTTNG_CONSUMER_STREAMS_SENT:
 829         {
 830                 struct lttng_consumer_channel *channel;
 831                 int ret_send_status;
 832
 833                 /*
 834                  * Get stream's channel reference. Needed when adding the stream to the
 835                  * global hash table.
 836                  */
 837                 channel = consumer_find_channel(msg.u.sent_streams.channel_key);
 838                 if (!channel) {
 839                         /*
 840                          * We could not find the channel. Can happen if cpu hotplug
 841                          * happens while tearing down.
 842                          */
 843                         ERR("Unable to find channel key %" PRIu64,
 844                                         msg.u.sent_streams.channel_key);
 845                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 846                 }
 847
 848                 health_code_update();
 849
 850                 /*
 851                  * Send status code to session daemon.
 852                  */
 853                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 854                 if (ret_send_status < 0 ||
 855                                 ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 856                         /* Somehow, the session daemon is not responding anymore. */
 857                         goto error_streams_sent_nosignal;
 858                 }
 859
 860                 health_code_update();
 861
 862                 /*
 863                  * We should not send this message if we don't monitor the
 864                  * streams in this channel.
 865                  */
 866                 if (!channel->monitor) {
 867                         goto end_error_streams_sent;
 868                 }
 869
 870                 health_code_update();
 871                 /* Send stream to relayd if the stream has an ID. */
 872                 if (msg.u.sent_streams.net_seq_idx != (uint64_t) -1ULL) {
 873                         int ret_send_relay_streams;
 874
 875                         ret_send_relay_streams = consumer_send_relayd_streams_sent(
 876                                         msg.u.sent_streams.net_seq_idx);
 877                         if (ret_send_relay_streams < 0) {
 878                                 goto error_streams_sent_nosignal;
 879                         }
 880                         channel->streams_sent_to_relayd = true;
 881                 }
 882 end_error_streams_sent:
 883                 break;
 884 error_streams_sent_nosignal:
 885                 goto end_nosignal;
 886         }
 887         case LTTNG_CONSUMER_UPDATE_STREAM:
 888         {
 889                 rcu_read_unlock();
 890                 return -ENOSYS;
 891         }
 892         case LTTNG_CONSUMER_DESTROY_RELAYD:
 893         {
 894                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 895                 struct consumer_relayd_sock_pair *relayd;
 896                 int ret_send_status;
 897
 898                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 899
 900                 /* Get relayd reference if exists. */
 901                 relayd = consumer_find_relayd(index);
 902                 if (relayd == NULL) {
 903                         DBG("Unable to find relayd %" PRIu64, index);
 904                         ret_code = LTTCOMM_CONSUMERD_RELAYD_FAIL;
 905                 }
 906
 907                 /*
 908                  * Each relayd socket pair has a refcount of stream attached to it
 909                  * which tells if the relayd is still active or not depending on the
 910                  * refcount value.
 911                  *
 912                  * This will set the destroy flag of the relayd object and destroy it
 913                  * if the refcount reaches zero when called.
 914                  *
 915                  * The destroy can happen either here or when a stream fd hangs up.
 916                  */
 917                 if (relayd) {
 918                         consumer_flag_relayd_for_destroy(relayd);
 919                 }
 920
 921                 health_code_update();
 922
 923                 ret_send_status = consumer_send_status_msg(sock, ret_code);
 924                 if (ret_send_status < 0) {
 925                         /* Somehow, the session daemon is not responding anymore. */
 926                         goto error_fatal;
 927                 }
 928
 929                 goto end_nosignal;
 930         }
 931         case LTTNG_CONSUMER_DATA_PENDING:
 932         {
 933                 int32_t ret_data_pending;
 934                 uint64_t id = msg.u.data_pending.session_id;
 935                 ssize_t ret_send;
 936
 937                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 938
 939                 ret_data_pending = consumer_data_pending(id);
 940
 941                 health_code_update();
 942
 943                 /* Send back returned value to session daemon */
 944                 ret_send = lttcomm_send_unix_sock(sock, &ret_data_pending,
 945                                 sizeof(ret_data_pending));
 946                 if (ret_send < 0) {
 947                         PERROR("send data pending ret code");
 948                         goto error_fatal;
 949                 }
 950
 951                 /*
 952                  * No need to send back a status message since the data pending
 953                  * returned value is the response.
 954                  */
 955                 break;
 956         }
 957         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 958         {
 959                 struct lttng_consumer_channel *channel;
 960                 uint64_t key = msg.u.snapshot_channel.key;
 961                 int ret_send_status;
 962
 963                 channel = consumer_find_channel(key);
 964                 if (!channel) {
 965                         ERR("Channel %" PRIu64 " not found", key);
 966                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 967                 } else {
 968                         pthread_mutex_lock(&channel->lock);
 969                         if (msg.u.snapshot_channel.metadata == 1) {
 970                                 int ret_snapshot;
 971
 972                                 ret_snapshot = lttng_kconsumer_snapshot_metadata(
 973                                                 channel, key,
 974                                                 msg.u.snapshot_channel.pathname,
 975                                                 msg.u.snapshot_channel.relayd_id,
 976                                                 ctx);
 977                                 if (ret_snapshot < 0) {
 978                                         ERR("Snapshot metadata failed");
 979                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 980                                 }
 981                         } else {
 982                                 int ret_snapshot;
 983
 984                                 ret_snapshot = lttng_kconsumer_snapshot_channel(
 985                                                 channel, key,
 986                                                 msg.u.snapshot_channel.pathname,
 987                                                 msg.u.snapshot_channel.relayd_id,
 988                                                 msg.u.snapshot_channel
 989                                                                 .nb_packets_per_stream,
 990                                                 ctx);
 991                                 if (ret_snapshot < 0) {
 992                                         ERR("Snapshot channel failed");
 993                                         ret_code = LTTCOMM_CONSUMERD_SNAPSHOT_FAILED;
 994                                 }
 995                         }
 996                         pthread_mutex_unlock(&channel->lock);
 997                 }
 998                 health_code_update();
 999
1000                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1001                 if (ret_send_status < 0) {
1002                         /* Somehow, the session daemon is not responding anymore. */
1003                         goto end_nosignal;
1004                 }
1005                 break;
1006         }
1007         case LTTNG_CONSUMER_DESTROY_CHANNEL:
1008         {
1009                 uint64_t key = msg.u.destroy_channel.key;
1010                 struct lttng_consumer_channel *channel;
1011                 int ret_send_status;
1012
1013                 channel = consumer_find_channel(key);
1014                 if (!channel) {
1015                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
1016                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1017                 }
1018
1019                 health_code_update();
1020
1021                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1022                 if (ret_send_status < 0) {
1023                         /* Somehow, the session daemon is not responding anymore. */
1024                         goto end_destroy_channel;
1025                 }
1026
1027                 health_code_update();
1028
1029                 /* Stop right now if no channel was found. */
1030                 if (!channel) {
1031                         goto end_destroy_channel;
1032                 }
1033
1034                 /*
1035                  * This command should ONLY be issued for channel with streams set in
1036                  * no monitor mode.
1037                  */
1038                 assert(!channel->monitor);
1039
1040                 /*
1041                  * The refcount should ALWAYS be 0 in the case of a channel in no
1042                  * monitor mode.
1043                  */
1044                 assert(!uatomic_sub_return(&channel->refcount, 1));
1045
1046                 consumer_del_channel(channel);
1047 end_destroy_channel:
1048                 goto end_nosignal;
1049         }
1050         case LTTNG_CONSUMER_DISCARDED_EVENTS:
1051         {
1052                 ssize_t ret;
1053                 uint64_t count;
1054                 struct lttng_consumer_channel *channel;
1055                 uint64_t id = msg.u.discarded_events.session_id;
1056                 uint64_t key = msg.u.discarded_events.channel_key;
1057
1058                 DBG("Kernel consumer discarded events command for session id %"
1059                                 PRIu64 ", channel key %" PRIu64, id, key);
1060
1061                 channel = consumer_find_channel(key);
1062                 if (!channel) {
1063                         ERR("Kernel consumer discarded events channel %"
1064                                         PRIu64 " not found", key);
1065                         count = 0;
1066                 } else {
1067                         count = channel->discarded_events;
1068                 }
1069
1070                 health_code_update();
1071
1072                 /* Send back returned value to session daemon */
1073                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1074                 if (ret < 0) {
1075                         PERROR("send discarded events");
1076                         goto error_fatal;
1077                 }
1078
1079                 break;
1080         }
1081         case LTTNG_CONSUMER_LOST_PACKETS:
1082         {
1083                 ssize_t ret;
1084                 uint64_t count;
1085                 struct lttng_consumer_channel *channel;
1086                 uint64_t id = msg.u.lost_packets.session_id;
1087                 uint64_t key = msg.u.lost_packets.channel_key;
1088
1089                 DBG("Kernel consumer lost packets command for session id %"
1090                                 PRIu64 ", channel key %" PRIu64, id, key);
1091
1092                 channel = consumer_find_channel(key);
1093                 if (!channel) {
1094                         ERR("Kernel consumer lost packets channel %"
1095                                         PRIu64 " not found", key);
1096                         count = 0;
1097                 } else {
1098                         count = channel->lost_packets;
1099                 }
1100
1101                 health_code_update();
1102
1103                 /* Send back returned value to session daemon */
1104                 ret = lttcomm_send_unix_sock(sock, &count, sizeof(count));
1105                 if (ret < 0) {
1106                         PERROR("send lost packets");
1107                         goto error_fatal;
1108                 }
1109
1110                 break;
1111         }
1112         case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
1113         {
1114                 int channel_monitor_pipe;
1115                 int ret_send_status, ret_set_channel_monitor_pipe;
1116                 ssize_t ret_recv;
1117
1118                 ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1119                 /* Successfully received the command's type. */
1120                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1121                 if (ret_send_status < 0) {
1122                         goto error_fatal;
1123                 }
1124
1125                 ret_recv = lttcomm_recv_fds_unix_sock(
1126                                 sock, &channel_monitor_pipe, 1);
1127                 if (ret_recv != sizeof(channel_monitor_pipe)) {
1128                         ERR("Failed to receive channel monitor pipe");
1129                         goto error_fatal;
1130                 }
1131
1132                 DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
1133                 ret_set_channel_monitor_pipe =
1134                                 consumer_timer_thread_set_channel_monitor_pipe(
1135                                                 channel_monitor_pipe);
1136                 if (!ret_set_channel_monitor_pipe) {
1137                         int flags;
1138                         int ret_fcntl;
1139
1140                         ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1141                         /* Set the pipe as non-blocking. */
1142                         ret_fcntl = fcntl(channel_monitor_pipe, F_GETFL, 0);
1143                         if (ret_fcntl == -1) {
1144                                 PERROR("fcntl get flags of the channel monitoring pipe");
1145                                 goto error_fatal;
1146                         }
1147                         flags = ret_fcntl;
1148
1149                         ret_fcntl = fcntl(channel_monitor_pipe, F_SETFL,
1150                                         flags | O_NONBLOCK);
1151                         if (ret_fcntl == -1) {
1152                                 PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
1153                                 goto error_fatal;
1154                         }
1155                         DBG("Channel monitor pipe set as non-blocking");
1156                 } else {
1157                         ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
1158                 }
1159                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1160                 if (ret_send_status < 0) {
1161                         goto error_fatal;
1162                 }
1163                 break;
1164         }
1165         case LTTNG_CONSUMER_ROTATE_CHANNEL:
1166         {
1167                 struct lttng_consumer_channel *channel;
1168                 uint64_t key = msg.u.rotate_channel.key;
1169                 int ret_send_status;
1170
1171                 DBG("Consumer rotate channel %" PRIu64, key);
1172
1173                 channel = consumer_find_channel(key);
1174                 if (!channel) {
1175                         ERR("Channel %" PRIu64 " not found", key);
1176                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1177                 } else {
1178                         /*
1179                          * Sample the rotate position of all the streams in this channel.
1180                          */
1181                         int ret_rotate_channel;
1182
1183                         ret_rotate_channel = lttng_consumer_rotate_channel(
1184                                         channel, key,
1185                                         msg.u.rotate_channel.relayd_id,
1186                                         msg.u.rotate_channel.metadata, ctx);
1187                         if (ret_rotate_channel < 0) {
1188                                 ERR("Rotate channel failed");
1189                                 ret_code = LTTCOMM_CONSUMERD_ROTATION_FAIL;
1190                         }
1191
1192                         health_code_update();
1193                 }
1194
1195                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1196                 if (ret_send_status < 0) {
1197                         /* Somehow, the session daemon is not responding anymore. */
1198                         goto error_rotate_channel;
1199                 }
1200                 if (channel) {
1201                         /* Rotate the streams that are ready right now. */
1202                         int ret_rotate;
1203
1204                         ret_rotate = lttng_consumer_rotate_ready_streams(
1205                                         channel, key, ctx);
1206                         if (ret_rotate < 0) {
1207                                 ERR("Rotate ready streams failed");
1208                         }
1209                 }
1210                 break;
1211 error_rotate_channel:
1212                 goto end_nosignal;
1213         }
1214         case LTTNG_CONSUMER_CLEAR_CHANNEL:
1215         {
1216                 struct lttng_consumer_channel *channel;
1217                 uint64_t key = msg.u.clear_channel.key;
1218                 int ret_send_status;
1219
1220                 channel = consumer_find_channel(key);
1221                 if (!channel) {
1222                         DBG("Channel %" PRIu64 " not found", key);
1223                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1224                 } else {
1225                         int ret_clear_channel;
1226
1227                         ret_clear_channel =
1228                                         lttng_consumer_clear_channel(channel);
1229                         if (ret_clear_channel) {
1230                                 ERR("Clear channel failed");
1231                                 ret_code = ret_clear_channel;
1232                         }
1233
1234                         health_code_update();
1235                 }
1236
1237                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1238                 if (ret_send_status < 0) {
1239                         /* Somehow, the session daemon is not responding anymore. */
1240                         goto end_nosignal;
1241                 }
1242
1243                 break;
1244         }
1245         case LTTNG_CONSUMER_INIT:
1246         {
1247                 int ret_send_status;
1248
1249                 ret_code = lttng_consumer_init_command(ctx,
1250                                 msg.u.init.sessiond_uuid);
1251                 health_code_update();
1252                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1253                 if (ret_send_status < 0) {
1254                         /* Somehow, the session daemon is not responding anymore. */
1255                         goto end_nosignal;
1256                 }
1257                 break;
1258         }
1259         case LTTNG_CONSUMER_CREATE_TRACE_CHUNK:
1260         {
1261                 const struct lttng_credentials credentials = {
1262                         .uid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.uid),
1263                         .gid = LTTNG_OPTIONAL_INIT_VALUE(msg.u.create_trace_chunk.credentials.value.gid),
1264                 };
1265                 const bool is_local_trace =
1266                                 !msg.u.create_trace_chunk.relayd_id.is_set;
1267                 const uint64_t relayd_id =
1268                                 msg.u.create_trace_chunk.relayd_id.value;
1269                 const char *chunk_override_name =
1270                                 *msg.u.create_trace_chunk.override_name ?
1271                                         msg.u.create_trace_chunk.override_name :
1272                                         NULL;
1273                 struct lttng_directory_handle *chunk_directory_handle = NULL;
1274
1275                 /*
1276                  * The session daemon will only provide a chunk directory file
1277                  * descriptor for local traces.
1278                  */
1279                 if (is_local_trace) {
1280                         int chunk_dirfd;
1281                         int ret_send_status;
1282                         ssize_t ret_recv;
1283
1284                         /* Acnowledge the reception of the command. */
1285                         ret_send_status = consumer_send_status_msg(
1286                                         sock, LTTCOMM_CONSUMERD_SUCCESS);
1287                         if (ret_send_status < 0) {
1288                                 /* Somehow, the session daemon is not responding anymore. */
1289                                 goto end_nosignal;
1290                         }
1291
1292                         ret_recv = lttcomm_recv_fds_unix_sock(
1293                                         sock, &chunk_dirfd, 1);
1294                         if (ret_recv != sizeof(chunk_dirfd)) {
1295                                 ERR("Failed to receive trace chunk directory file descriptor");
1296                                 goto error_fatal;
1297                         }
1298
1299                         DBG("Received trace chunk directory fd (%d)",
1300                                         chunk_dirfd);
1301                         chunk_directory_handle = lttng_directory_handle_create_from_dirfd(
1302                                         chunk_dirfd);
1303                         if (!chunk_directory_handle) {
1304                                 ERR("Failed to initialize chunk directory handle from directory file descriptor");
1305                                 if (close(chunk_dirfd)) {
1306                                         PERROR("Failed to close chunk directory file descriptor");
1307                                 }
1308                                 goto error_fatal;
1309                         }
1310                 }
1311
1312                 ret_code = lttng_consumer_create_trace_chunk(
1313                                 !is_local_trace ? &relayd_id : NULL,
1314                                 msg.u.create_trace_chunk.session_id,
1315                                 msg.u.create_trace_chunk.chunk_id,
1316                                 (time_t) msg.u.create_trace_chunk
1317                                                 .creation_timestamp,
1318                                 chunk_override_name,
1319                                 msg.u.create_trace_chunk.credentials.is_set ?
1320                                                 &credentials :
1321                                                 NULL,
1322                                 chunk_directory_handle);
1323                 lttng_directory_handle_put(chunk_directory_handle);
1324                 goto end_msg_sessiond;
1325         }
1326         case LTTNG_CONSUMER_CLOSE_TRACE_CHUNK:
1327         {
1328                 enum lttng_trace_chunk_command_type close_command =
1329                                 msg.u.close_trace_chunk.close_command.value;
1330                 const uint64_t relayd_id =
1331                                 msg.u.close_trace_chunk.relayd_id.value;
1332                 struct lttcomm_consumer_close_trace_chunk_reply reply;
1333                 char path[LTTNG_PATH_MAX];
1334                 ssize_t ret_send;
1335
1336                 ret_code = lttng_consumer_close_trace_chunk(
1337                                 msg.u.close_trace_chunk.relayd_id.is_set ?
1338                                                 &relayd_id :
1339                                                 NULL,
1340                                 msg.u.close_trace_chunk.session_id,
1341                                 msg.u.close_trace_chunk.chunk_id,
1342                                 (time_t) msg.u.close_trace_chunk.close_timestamp,
1343                                 msg.u.close_trace_chunk.close_command.is_set ?
1344                                                 &close_command :
1345                                                 NULL, path);
1346                 reply.ret_code = ret_code;
1347                 reply.path_length = strlen(path) + 1;
1348                 ret_send = lttcomm_send_unix_sock(sock, &reply, sizeof(reply));
1349                 if (ret_send != sizeof(reply)) {
1350                         goto error_fatal;
1351                 }
1352                 ret_send = lttcomm_send_unix_sock(
1353                                 sock, path, reply.path_length);
1354                 if (ret_send != reply.path_length) {
1355                         goto error_fatal;
1356                 }
1357                 goto end_nosignal;
1358         }
1359         case LTTNG_CONSUMER_TRACE_CHUNK_EXISTS:
1360         {
1361                 const uint64_t relayd_id =
1362                                 msg.u.trace_chunk_exists.relayd_id.value;
1363
1364                 ret_code = lttng_consumer_trace_chunk_exists(
1365                                 msg.u.trace_chunk_exists.relayd_id.is_set ?
1366                                                 &relayd_id : NULL,
1367                                 msg.u.trace_chunk_exists.session_id,
1368                                 msg.u.trace_chunk_exists.chunk_id);
1369                 goto end_msg_sessiond;
1370         }
1371         case LTTNG_CONSUMER_OPEN_CHANNEL_PACKETS:
1372         {
1373                 const uint64_t key = msg.u.open_channel_packets.key;
1374                 struct lttng_consumer_channel *channel =
1375                                 consumer_find_channel(key);
1376
1377                 if (channel) {
1378                         pthread_mutex_lock(&channel->lock);
1379                         ret_code = lttng_consumer_open_channel_packets(channel);
1380                         pthread_mutex_unlock(&channel->lock);
1381                 } else {
1382                         WARN("Channel %" PRIu64 " not found", key);
1383                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
1384                 }
1385
1386                 health_code_update();
1387                 goto end_msg_sessiond;
1388         }
1389         default:
1390                 goto end_nosignal;
1391         }
1392
1393 end_nosignal:
1394         /*
1395          * Return 1 to indicate success since the 0 value can be a socket
1396          * shutdown during the recv() or send() call.
1397          */
1398         ret_func = 1;
1399         goto end;
1400 error_fatal:
1401         /* This will issue a consumer stop. */
1402         ret_func = -1;
1403         goto end;
1404 end_msg_sessiond:
1405         /*
1406          * The returned value here is not useful since either way we'll return 1 to
1407          * the caller because the session daemon socket management is done
1408          * elsewhere. Returning a negative code or 0 will shutdown the consumer.
1409          */
1410         {
1411                 int ret_send_status;
1412
1413                 ret_send_status = consumer_send_status_msg(sock, ret_code);
1414                 if (ret_send_status < 0) {
1415                         goto error_fatal;
1416                 }
1417         }
1418
1419         ret_func = 1;
1420
1421 end:
1422         health_code_update();
1423         rcu_read_unlock();
1424         return ret_func;
1425 }
1426
1427 /*
1428  * Sync metadata meaning request them to the session daemon and snapshot to the
1429  * metadata thread can consumer them.
1430  *
1431  * Metadata stream lock MUST be acquired.
1432  */
1433 enum sync_metadata_status lttng_kconsumer_sync_metadata(
1434                 struct lttng_consumer_stream *metadata)
1435 {
1436         int ret;
1437         enum sync_metadata_status status;
1438
1439         assert(metadata);
1440
1441         ret = kernctl_buffer_flush(metadata->wait_fd);
1442         if (ret < 0) {
1443                 ERR("Failed to flush kernel stream");
1444                 status = SYNC_METADATA_STATUS_ERROR;
1445                 goto end;
1446         }
1447
1448         ret = kernctl_snapshot(metadata->wait_fd);
1449         if (ret < 0) {
1450                 if (errno == EAGAIN) {
1451                         /* No new metadata, exit. */
1452                         DBG("Sync metadata, no new kernel metadata");
1453                         status = SYNC_METADATA_STATUS_NO_DATA;
1454                 } else {
1455                         ERR("Sync metadata, taking kernel snapshot failed.");
1456                         status = SYNC_METADATA_STATUS_ERROR;
1457                 }
1458         } else {
1459                 status = SYNC_METADATA_STATUS_NEW_DATA;
1460         }
1461
1462 end:
1463         return status;
1464 }
1465
1466 static
1467 int extract_common_subbuffer_info(struct lttng_consumer_stream *stream,
1468                 struct stream_subbuffer *subbuf)
1469 {
1470         int ret;
1471
1472         ret = kernctl_get_subbuf_size(
1473                         stream->wait_fd, &subbuf->info.data.subbuf_size);
1474         if (ret) {
1475                 goto end;
1476         }
1477
1478         ret = kernctl_get_padded_subbuf_size(
1479                         stream->wait_fd, &subbuf->info.data.padded_subbuf_size);
1480         if (ret) {
1481                 goto end;
1482         }
1483
1484 end:
1485         return ret;
1486 }
1487
1488 static
1489 int extract_metadata_subbuffer_info(struct lttng_consumer_stream *stream,
1490                 struct stream_subbuffer *subbuf)
1491 {
1492         int ret;
1493
1494         ret = extract_common_subbuffer_info(stream, subbuf);
1495         if (ret) {
1496                 goto end;
1497         }
1498
1499         ret = kernctl_get_metadata_version(
1500                         stream->wait_fd, &subbuf->info.metadata.version);
1501         if (ret) {
1502                 goto end;
1503         }
1504
1505 end:
1506         return ret;
1507 }
1508
1509 static
1510 int extract_data_subbuffer_info(struct lttng_consumer_stream *stream,
1511                 struct stream_subbuffer *subbuf)
1512 {
1513         int ret;
1514
1515         ret = extract_common_subbuffer_info(stream, subbuf);
1516         if (ret) {
1517                 goto end;
1518         }
1519
1520         ret = kernctl_get_packet_size(
1521                         stream->wait_fd, &subbuf->info.data.packet_size);
1522         if (ret < 0) {
1523                 PERROR("Failed to get sub-buffer packet size");
1524                 goto end;
1525         }
1526
1527         ret = kernctl_get_content_size(
1528                         stream->wait_fd, &subbuf->info.data.content_size);
1529         if (ret < 0) {
1530                 PERROR("Failed to get sub-buffer content size");
1531                 goto end;
1532         }
1533
1534         ret = kernctl_get_timestamp_begin(
1535                         stream->wait_fd, &subbuf->info.data.timestamp_begin);
1536         if (ret < 0) {
1537                 PERROR("Failed to get sub-buffer begin timestamp");
1538                 goto end;
1539         }
1540
1541         ret = kernctl_get_timestamp_end(
1542                         stream->wait_fd, &subbuf->info.data.timestamp_end);
1543         if (ret < 0) {
1544                 PERROR("Failed to get sub-buffer end timestamp");
1545                 goto end;
1546         }
1547
1548         ret = kernctl_get_events_discarded(
1549                         stream->wait_fd, &subbuf->info.data.events_discarded);
1550         if (ret) {
1551                 PERROR("Failed to get sub-buffer events discarded count");
1552                 goto end;
1553         }
1554
1555         ret = kernctl_get_sequence_number(stream->wait_fd,
1556                         &subbuf->info.data.sequence_number.value);
1557         if (ret) {
1558                 /* May not be supported by older LTTng-modules. */
1559                 if (ret != -ENOTTY) {
1560                         PERROR("Failed to get sub-buffer sequence number");
1561                         goto end;
1562                 }
1563         } else {
1564                 subbuf->info.data.sequence_number.is_set = true;
1565         }
1566
1567         ret = kernctl_get_stream_id(
1568                         stream->wait_fd, &subbuf->info.data.stream_id);
1569         if (ret < 0) {
1570                 PERROR("Failed to get stream id");
1571                 goto end;
1572         }
1573
1574         ret = kernctl_get_instance_id(stream->wait_fd,
1575                         &subbuf->info.data.stream_instance_id.value);
1576         if (ret) {
1577                 /* May not be supported by older LTTng-modules. */
1578                 if (ret != -ENOTTY) {
1579                         PERROR("Failed to get stream instance id");
1580                         goto end;
1581                 }
1582         } else {
1583                 subbuf->info.data.stream_instance_id.is_set = true;
1584         }
1585 end:
1586         return ret;
1587 }
1588
1589 static
1590 int get_subbuffer_common(struct lttng_consumer_stream *stream,
1591                 struct stream_subbuffer *subbuffer)
1592 {
1593         int ret;
1594
1595         ret = kernctl_get_next_subbuf(stream->wait_fd);
1596         if (ret) {
1597                 goto end;
1598         }
1599
1600         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1601                         stream, subbuffer);
1602 end:
1603         return ret;
1604 }
1605
1606 static
1607 int get_next_subbuffer_splice(struct lttng_consumer_stream *stream,
1608                 struct stream_subbuffer *subbuffer)
1609 {
1610         int ret;
1611
1612         ret = get_subbuffer_common(stream, subbuffer);
1613         if (ret) {
1614                 goto end;
1615         }
1616
1617         subbuffer->buffer.fd = stream->wait_fd;
1618 end:
1619         return ret;
1620 }
1621
1622 static
1623 int get_next_subbuffer_mmap(struct lttng_consumer_stream *stream,
1624                 struct stream_subbuffer *subbuffer)
1625 {
1626         int ret;
1627         const char *addr;
1628
1629         ret = get_subbuffer_common(stream, subbuffer);
1630         if (ret) {
1631                 goto end;
1632         }
1633
1634         ret = get_current_subbuf_addr(stream, &addr);
1635         if (ret) {
1636                 goto end;
1637         }
1638
1639         subbuffer->buffer.buffer = lttng_buffer_view_init(
1640                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1641 end:
1642         return ret;
1643 }
1644
1645 static
1646 int get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
1647                 struct stream_subbuffer *subbuffer)
1648 {
1649         int ret;
1650         const char *addr;
1651         bool coherent;
1652
1653         ret = kernctl_get_next_subbuf_metadata_check(stream->wait_fd,
1654                         &coherent);
1655         if (ret) {
1656                 goto end;
1657         }
1658
1659         ret = stream->read_subbuffer_ops.extract_subbuffer_info(
1660                         stream, subbuffer);
1661         if (ret) {
1662                 goto end;
1663         }
1664
1665         LTTNG_OPTIONAL_SET(&subbuffer->info.metadata.coherent, coherent);
1666
1667         ret = get_current_subbuf_addr(stream, &addr);
1668         if (ret) {
1669                 goto end;
1670         }
1671
1672         subbuffer->buffer.buffer = lttng_buffer_view_init(
1673                         addr, 0, subbuffer->info.data.padded_subbuf_size);
1674         DBG("Got metadata packet with padded_subbuf_size = %lu, coherent = %s",
1675                         subbuffer->info.metadata.padded_subbuf_size,
1676                         coherent ? "true" : "false");
1677 end:
1678         return ret;
1679 }
1680
1681 static
1682 int put_next_subbuffer(struct lttng_consumer_stream *stream,
1683                 struct stream_subbuffer *subbuffer)
1684 {
1685         const int ret = kernctl_put_next_subbuf(stream->wait_fd);
1686
1687         if (ret) {
1688                 if (ret == -EFAULT) {
1689                         PERROR("Error in unreserving sub buffer");
1690                 } else if (ret == -EIO) {
1691                         /* Should never happen with newer LTTng versions */
1692                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted");
1693                 }
1694         }
1695
1696         return ret;
1697 }
1698
1699 static
1700 bool is_get_next_check_metadata_available(int tracer_fd)
1701 {
1702         const int ret = kernctl_get_next_subbuf_metadata_check(tracer_fd, NULL);
1703         const bool available = ret != -ENOTTY;
1704
1705         if (ret == 0) {
1706                 /* get succeeded, make sure to put the subbuffer. */
1707                 kernctl_put_subbuf(tracer_fd);
1708         }
1709
1710         return available;
1711 }
1712
1713 static
1714 int lttng_kconsumer_set_stream_ops(
1715                 struct lttng_consumer_stream *stream)
1716 {
1717         int ret = 0;
1718
1719         if (stream->metadata_flag && stream->chan->is_live) {
1720                 DBG("Attempting to enable metadata bucketization for live consumers");
1721                 if (is_get_next_check_metadata_available(stream->wait_fd)) {
1722                         DBG("Kernel tracer supports get_next_subbuffer_metadata_check, metadata will be accumulated until a coherent state is reached");
1723                         stream->read_subbuffer_ops.get_next_subbuffer =
1724                                         get_next_subbuffer_metadata_check;
1725                         ret = consumer_stream_enable_metadata_bucketization(
1726                                         stream);
1727                         if (ret) {
1728                                 goto end;
1729                         }
1730                 } else {
1731                         /*
1732                          * The kernel tracer version is too old to indicate
1733                          * when the metadata stream has reached a "coherent"
1734                          * (parseable) point.
1735                          *
1736                          * This means that a live viewer may see an incoherent
1737                          * sequence of metadata and fail to parse it.
1738                          */
1739                         WARN("Kernel tracer does not support get_next_subbuffer_metadata_check which may cause live clients to fail to parse the metadata stream");
1740                         metadata_bucket_destroy(stream->metadata_bucket);
1741                         stream->metadata_bucket = NULL;
1742                 }
1743         }
1744
1745         if (!stream->read_subbuffer_ops.get_next_subbuffer) {
1746                 if (stream->chan->output == CONSUMER_CHANNEL_MMAP) {
1747                         stream->read_subbuffer_ops.get_next_subbuffer =
1748                                         get_next_subbuffer_mmap;
1749                 } else {
1750                         stream->read_subbuffer_ops.get_next_subbuffer =
1751                                         get_next_subbuffer_splice;
1752                 }
1753         }
1754
1755         if (stream->metadata_flag) {
1756                 stream->read_subbuffer_ops.extract_subbuffer_info =
1757                                 extract_metadata_subbuffer_info;
1758         } else {
1759                 stream->read_subbuffer_ops.extract_subbuffer_info =
1760                                 extract_data_subbuffer_info;
1761                 if (stream->chan->is_live) {
1762                         stream->read_subbuffer_ops.send_live_beacon =
1763                                         consumer_flush_kernel_index;
1764                 }
1765         }
1766
1767         stream->read_subbuffer_ops.put_next_subbuffer = put_next_subbuffer;
1768 end:
1769         return ret;
1770 }
1771
1772 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1773 {
1774         int ret;
1775
1776         assert(stream);
1777
1778         /*
1779          * Don't create anything if this is set for streaming or if there is
1780          * no current trace chunk on the parent channel.
1781          */
1782         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor &&
1783                         stream->chan->trace_chunk) {
1784                 ret = consumer_stream_create_output_files(stream, true);
1785                 if (ret) {
1786                         goto error;
1787                 }
1788         }
1789
1790         if (stream->output == LTTNG_EVENT_MMAP) {
1791                 /* get the len of the mmap region */
1792                 unsigned long mmap_len;
1793
1794                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1795                 if (ret != 0) {
1796                         PERROR("kernctl_get_mmap_len");
1797                         goto error_close_fd;
1798                 }
1799                 stream->mmap_len = (size_t) mmap_len;
1800
1801                 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
1802                                 MAP_PRIVATE, stream->wait_fd, 0);
1803                 if (stream->mmap_base == MAP_FAILED) {
1804                         PERROR("Error mmaping");
1805                         ret = -1;
1806                         goto error_close_fd;
1807                 }
1808         }
1809
1810         ret = lttng_kconsumer_set_stream_ops(stream);
1811         if (ret) {
1812                 goto error_close_fd;
1813         }
1814
1815         /* we return 0 to let the library handle the FD internally */
1816         return 0;
1817
1818 error_close_fd:
1819         if (stream->out_fd >= 0) {
1820                 int err;
1821
1822                 err = close(stream->out_fd);
1823                 assert(!err);
1824                 stream->out_fd = -1;
1825         }
1826 error:
1827         return ret;
1828 }
1829
1830 /*
1831  * Check if data is still being extracted from the buffers for a specific
1832  * stream. Consumer data lock MUST be acquired before calling this function
1833  * and the stream lock.
1834  *
1835  * Return 1 if the traced data are still getting read else 0 meaning that the
1836  * data is available for trace viewer reading.
1837  */
1838 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1839 {
1840         int ret;
1841
1842         assert(stream);
1843
1844         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1845                 ret = 0;
1846                 goto end;
1847         }
1848
1849         ret = kernctl_get_next_subbuf(stream->wait_fd);
1850         if (ret == 0) {
1851                 /* There is still data so let's put back this subbuffer. */
1852                 ret = kernctl_put_subbuf(stream->wait_fd);
1853                 assert(ret == 0);
1854                 ret = 1;   /* Data is pending */
1855                 goto end;
1856         }
1857
1858         /* Data is NOT pending and ready to be read. */
1859         ret = 0;
1860
1861 end:
1862         return ret;
1863 }