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

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  * Copyright (C) 2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <assert.h>
  22 #include <poll.h>
  23 #include <pthread.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/mman.h>
  27 #include <sys/socket.h>
  28 #include <sys/types.h>
  29 #include <inttypes.h>
  30 #include <unistd.h>
  31 #include <sys/stat.h>
  32
  33 #include <bin/lttng-consumerd/health-consumerd.h>
  34 #include <common/common.h>
  35 #include <common/kernel-ctl/kernel-ctl.h>
  36 #include <common/sessiond-comm/sessiond-comm.h>
  37 #include <common/sessiond-comm/relayd.h>
  38 #include <common/compat/fcntl.h>
  39 #include <common/compat/endian.h>
  40 #include <common/pipe.h>
  41 #include <common/relayd/relayd.h>
  42 #include <common/utils.h>
  43 #include <common/consumer/consumer-stream.h>
  44 #include <common/index/index.h>
  45 #include <common/consumer/consumer-timer.h>
  46
  47 #include "kernel-consumer.h"
  48
  49 extern struct lttng_consumer_global_data consumer_data;
  50 extern int consumer_poll_timeout;
  51 extern volatile int consumer_quit;
  52
  53 /*
  54  * Take a snapshot for a specific fd
  55  *
  56  * Returns 0 on success, < 0 on error
  57  */
  58 int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream *stream)
  59 {
  60         int ret = 0;
  61         int infd = stream->wait_fd;
  62
  63         ret = kernctl_snapshot(infd);
  64         if (ret != 0) {
  65                 PERROR("Getting sub-buffer snapshot.");
  66         }
  67
  68         return ret;
  69 }
  70
  71 /*
  72  * Get the produced position
  73  *
  74  * Returns 0 on success, < 0 on error
  75  */
  76 int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
  77                 unsigned long *pos)
  78 {
  79         int ret;
  80         int infd = stream->wait_fd;
  81
  82         ret = kernctl_snapshot_get_produced(infd, pos);
  83         if (ret != 0) {
  84                 PERROR("kernctl_snapshot_get_produced");
  85         }
  86
  87         return ret;
  88 }
  89
  90 /*
  91  * Get the consumerd position
  92  *
  93  * Returns 0 on success, < 0 on error
  94  */
  95 int lttng_kconsumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
  96                 unsigned long *pos)
  97 {
  98         int ret;
  99         int infd = stream->wait_fd;
 100
 101         ret = kernctl_snapshot_get_consumed(infd, pos);
 102         if (ret != 0) {
 103                 PERROR("kernctl_snapshot_get_consumed");
 104         }
 105
 106         return ret;
 107 }
 108
 109 /*
 110  * Take a snapshot of all the stream of a channel
 111  *
 112  * Returns 0 on success, < 0 on error
 113  */
 114 int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
 115                 uint64_t relayd_id, uint64_t nb_packets_per_stream,
 116                 struct lttng_consumer_local_data *ctx)
 117 {
 118         int ret;
 119         struct lttng_consumer_channel *channel;
 120         struct lttng_consumer_stream *stream;
 121
 122         DBG("Kernel consumer snapshot channel %" PRIu64, key);
 123
 124         rcu_read_lock();
 125
 126         channel = consumer_find_channel(key);
 127         if (!channel) {
 128                 ERR("No channel found for key %" PRIu64, key);
 129                 ret = -1;
 130                 goto end;
 131         }
 132
 133         /* Splice is not supported yet for channel snapshot. */
 134         if (channel->output != CONSUMER_CHANNEL_MMAP) {
 135                 ERR("Unsupported output %d", channel->output);
 136                 ret = -1;
 137                 goto end;
 138         }
 139
 140         cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
 141                 /* Are we at a position _before_ the first available packet ? */
 142                 bool before_first_packet = true;
 143                 unsigned long consumed_pos, produced_pos;
 144
 145                 health_code_update();
 146
 147                 /*
 148                  * Lock stream because we are about to change its state.
 149                  */
 150                 pthread_mutex_lock(&stream->lock);
 151
 152                 /*
 153                  * Assign the received relayd ID so we can use it for streaming. The streams
 154                  * are not visible to anyone so this is OK to change it.
 155                  */
 156                 stream->net_seq_idx = relayd_id;
 157                 channel->relayd_id = relayd_id;
 158                 if (relayd_id != (uint64_t) -1ULL) {
 159                         ret = consumer_send_relayd_stream(stream, path);
 160                         if (ret < 0) {
 161                                 ERR("sending stream to relayd");
 162                                 goto end_unlock;
 163                         }
 164                 } else {
 165                         ret = utils_create_stream_file(path, stream->name,
 166                                         stream->chan->tracefile_size,
 167                                         stream->tracefile_count_current,
 168                                         stream->uid, stream->gid, NULL);
 169                         if (ret < 0) {
 170                                 ERR("utils_create_stream_file");
 171                                 goto end_unlock;
 172                         }
 173
 174                         stream->out_fd = ret;
 175                         stream->tracefile_size_current = 0;
 176
 177                         DBG("Kernel consumer snapshot stream %s/%s (%" PRIu64 ")",
 178                                         path, stream->name, stream->key);
 179                 }
 180                 if (relayd_id != -1ULL) {
 181                         ret = consumer_send_relayd_streams_sent(relayd_id);
 182                         if (ret < 0) {
 183                                 ERR("sending streams sent to relayd");
 184                                 goto end_unlock;
 185                         }
 186                 }
 187
 188                 ret = kernctl_buffer_flush(stream->wait_fd);
 189                 if (ret < 0) {
 190                         ERR("Failed to flush kernel stream");
 191                         goto end_unlock;
 192                 }
 193
 194                 ret = lttng_kconsumer_take_snapshot(stream);
 195                 if (ret < 0) {
 196                         ERR("Taking kernel snapshot");
 197                         goto end_unlock;
 198                 }
 199
 200                 ret = lttng_kconsumer_get_produced_snapshot(stream, &produced_pos);
 201                 if (ret < 0) {
 202                         ERR("Produced kernel snapshot position");
 203                         goto end_unlock;
 204                 }
 205
 206                 ret = lttng_kconsumer_get_consumed_snapshot(stream, &consumed_pos);
 207                 if (ret < 0) {
 208                         ERR("Consumerd kernel snapshot position");
 209                         goto end_unlock;
 210                 }
 211
 212                 if (stream->max_sb_size == 0) {
 213                         ret = kernctl_get_max_subbuf_size(stream->wait_fd,
 214                                         &stream->max_sb_size);
 215                         if (ret < 0) {
 216                                 ERR("Getting kernel max_sb_size");
 217                                 goto end_unlock;
 218                         }
 219                 }
 220
 221                 consumed_pos = consumer_get_consume_start_pos(consumed_pos,
 222                                 produced_pos, nb_packets_per_stream,
 223                                 stream->max_sb_size);
 224
 225                 while (consumed_pos < produced_pos) {
 226                         ssize_t read_len;
 227                         unsigned long len, padded_len;
 228                         int lost_packet = 0;
 229
 230                         health_code_update();
 231
 232                         DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 233
 234                         ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
 235                         if (ret < 0) {
 236                                 if (ret != -EAGAIN) {
 237                                         PERROR("kernctl_get_subbuf snapshot");
 238                                         goto end_unlock;
 239                                 }
 240                                 DBG("Kernel consumer get subbuf failed. Skipping it.");
 241                                 consumed_pos += stream->max_sb_size;
 242
 243                                 /*
 244                                  * Start accounting lost packets only when we
 245                                  * already have extracted packets (to match the
 246                                  * content of the final snapshot).
 247                                  */
 248                                 if (!before_first_packet) {
 249                                         lost_packet = 1;
 250                                 }
 251                                 continue;
 252                         }
 253
 254                         ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
 255                         if (ret < 0) {
 256                                 ERR("Snapshot kernctl_get_subbuf_size");
 257                                 goto error_put_subbuf;
 258                         }
 259
 260                         ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
 261                         if (ret < 0) {
 262                                 ERR("Snapshot kernctl_get_padded_subbuf_size");
 263                                 goto error_put_subbuf;
 264                         }
 265
 266                         read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
 267                                         padded_len - len, NULL);
 268                         /*
 269                          * We write the padded len in local tracefiles but the data len
 270                          * when using a relay. Display the error but continue processing
 271                          * to try to release the subbuffer.
 272                          */
 273                         if (relayd_id != (uint64_t) -1ULL) {
 274                                 if (read_len != len) {
 275                                         ERR("Error sending to the relay (ret: %zd != len: %lu)",
 276                                                         read_len, len);
 277                                 }
 278                         } else {
 279                                 if (read_len != padded_len) {
 280                                         ERR("Error writing to tracefile (ret: %zd != len: %lu)",
 281                                                         read_len, padded_len);
 282                                 }
 283                         }
 284
 285                         ret = kernctl_put_subbuf(stream->wait_fd);
 286                         if (ret < 0) {
 287                                 ERR("Snapshot kernctl_put_subbuf");
 288                                 goto end_unlock;
 289                         }
 290                         consumed_pos += stream->max_sb_size;
 291
 292                         /*
 293                          * Only account lost packets located between
 294                          * succesfully extracted packets (do not account before
 295                          * and after since they are not visible in the
 296                          * resulting snapshot).
 297                          */
 298                         stream->chan->lost_packets += lost_packet;
 299                         lost_packet = 0;
 300                         before_first_packet = false;
 301                 }
 302
 303                 if (relayd_id == (uint64_t) -1ULL) {
 304                         if (stream->out_fd >= 0) {
 305                                 ret = close(stream->out_fd);
 306                                 if (ret < 0) {
 307                                         PERROR("Kernel consumer snapshot close out_fd");
 308                                         goto end_unlock;
 309                                 }
 310                                 stream->out_fd = -1;
 311                         }
 312                 } else {
 313                         close_relayd_stream(stream);
 314                         stream->net_seq_idx = (uint64_t) -1ULL;
 315                 }
 316                 pthread_mutex_unlock(&stream->lock);
 317         }
 318
 319         /* All good! */
 320         ret = 0;
 321         goto end;
 322
 323 error_put_subbuf:
 324         ret = kernctl_put_subbuf(stream->wait_fd);
 325         if (ret < 0) {
 326                 ERR("Snapshot kernctl_put_subbuf error path");
 327         }
 328 end_unlock:
 329         pthread_mutex_unlock(&stream->lock);
 330 end:
 331         rcu_read_unlock();
 332         return ret;
 333 }
 334
 335 /*
 336  * Read the whole metadata available for a snapshot.
 337  *
 338  * Returns 0 on success, < 0 on error
 339  */
 340 int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
 341                 uint64_t relayd_id, struct lttng_consumer_local_data *ctx)
 342 {
 343         int ret, use_relayd = 0;
 344         ssize_t ret_read;
 345         struct lttng_consumer_channel *metadata_channel;
 346         struct lttng_consumer_stream *metadata_stream;
 347
 348         assert(ctx);
 349
 350         DBG("Kernel consumer snapshot metadata with key %" PRIu64 " at path %s",
 351                         key, path);
 352
 353         rcu_read_lock();
 354
 355         metadata_channel = consumer_find_channel(key);
 356         if (!metadata_channel) {
 357                 ERR("Kernel snapshot metadata not found for key %" PRIu64, key);
 358                 ret = -1;
 359                 goto error;
 360         }
 361
 362         metadata_stream = metadata_channel->metadata_stream;
 363         assert(metadata_stream);
 364
 365         /* Flag once that we have a valid relayd for the stream. */
 366         if (relayd_id != (uint64_t) -1ULL) {
 367                 use_relayd = 1;
 368         }
 369
 370         if (use_relayd) {
 371                 ret = consumer_send_relayd_stream(metadata_stream, path);
 372                 if (ret < 0) {
 373                         goto error;
 374                 }
 375         } else {
 376                 ret = utils_create_stream_file(path, metadata_stream->name,
 377                                 metadata_stream->chan->tracefile_size,
 378                                 metadata_stream->tracefile_count_current,
 379                                 metadata_stream->uid, metadata_stream->gid, NULL);
 380                 if (ret < 0) {
 381                         goto error;
 382                 }
 383                 metadata_stream->out_fd = ret;
 384         }
 385
 386         do {
 387                 health_code_update();
 388
 389                 ret_read = lttng_kconsumer_read_subbuffer(metadata_stream, ctx);
 390                 if (ret_read < 0) {
 391                         if (ret_read != -EAGAIN) {
 392                                 ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
 393                                                 ret_read);
 394                                 goto error;
 395                         }
 396                         /* ret_read is negative at this point so we will exit the loop. */
 397                         continue;
 398                 }
 399         } while (ret_read >= 0);
 400
 401         if (use_relayd) {
 402                 close_relayd_stream(metadata_stream);
 403                 metadata_stream->net_seq_idx = (uint64_t) -1ULL;
 404         } else {
 405                 if (metadata_stream->out_fd >= 0) {
 406                         ret = close(metadata_stream->out_fd);
 407                         if (ret < 0) {
 408                                 PERROR("Kernel consumer snapshot metadata close out_fd");
 409                                 /*
 410                                  * Don't go on error here since the snapshot was successful at this
 411                                  * point but somehow the close failed.
 412                                  */
 413                         }
 414                         metadata_stream->out_fd = -1;
 415                 }
 416         }
 417
 418         ret = 0;
 419
 420         cds_list_del(&metadata_stream->send_node);
 421         consumer_stream_destroy(metadata_stream, NULL);
 422         metadata_channel->metadata_stream = NULL;
 423 error:
 424         rcu_read_unlock();
 425         return ret;
 426 }
 427
 428 /*
 429  * Receive command from session daemon and process it.
 430  *
 431  * Return 1 on success else a negative value or 0.
 432  */
 433 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 434                 int sock, struct pollfd *consumer_sockpoll)
 435 {
 436         ssize_t ret;
 437         enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
 438         struct lttcomm_consumer_msg msg;
 439
 440         health_code_update();
 441
 442         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 443         if (ret != sizeof(msg)) {
 444                 if (ret > 0) {
 445                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 446                         ret = -1;
 447                 }
 448                 return ret;
 449         }
 450
 451         health_code_update();
 452
 453         /* Deprecated command */
 454         assert(msg.cmd_type != LTTNG_CONSUMER_STOP);
 455
 456         health_code_update();
 457
 458         /* relayd needs RCU read-side protection */
 459         rcu_read_lock();
 460
 461         switch (msg.cmd_type) {
 462         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 463         {
 464                 /* Session daemon status message are handled in the following call. */
 465                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 466                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 467                                 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
 468                                  msg.u.relayd_sock.relayd_session_id);
 469                 goto end_nosignal;
 470         }
 471         case LTTNG_CONSUMER_ADD_CHANNEL:
 472         {
 473                 struct lttng_consumer_channel *new_channel;
 474                 int ret_recv;
 475
 476                 health_code_update();
 477
 478                 /* First send a status message before receiving the fds. */
 479                 ret = consumer_send_status_msg(sock, ret_code);
 480                 if (ret < 0) {
 481                         /* Somehow, the session daemon is not responding anymore. */
 482                         goto error_fatal;
 483                 }
 484
 485                 health_code_update();
 486
 487                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 488                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 489                                 msg.u.channel.session_id, msg.u.channel.pathname,
 490                                 msg.u.channel.name, msg.u.channel.uid, msg.u.channel.gid,
 491                                 msg.u.channel.relayd_id, msg.u.channel.output,
 492                                 msg.u.channel.tracefile_size,
 493                                 msg.u.channel.tracefile_count, 0,
 494                                 msg.u.channel.monitor,
 495                                 msg.u.channel.live_timer_interval,
 496                                 NULL, NULL);
 497                 if (new_channel == NULL) {
 498                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 499                         goto end_nosignal;
 500                 }
 501                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 502                 switch (msg.u.channel.output) {
 503                 case LTTNG_EVENT_SPLICE:
 504                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 505                         break;
 506                 case LTTNG_EVENT_MMAP:
 507                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 508                         break;
 509                 default:
 510                         ERR("Channel output unknown %d", msg.u.channel.output);
 511                         goto end_nosignal;
 512                 }
 513
 514                 /* Translate and save channel type. */
 515                 switch (msg.u.channel.type) {
 516                 case CONSUMER_CHANNEL_TYPE_DATA:
 517                 case CONSUMER_CHANNEL_TYPE_METADATA:
 518                         new_channel->type = msg.u.channel.type;
 519                         break;
 520                 default:
 521                         assert(0);
 522                         goto end_nosignal;
 523                 };
 524
 525                 health_code_update();
 526
 527                 if (ctx->on_recv_channel != NULL) {
 528                         ret_recv = ctx->on_recv_channel(new_channel);
 529                         if (ret_recv == 0) {
 530                                 ret = consumer_add_channel(new_channel, ctx);
 531                         } else if (ret_recv < 0) {
 532                                 goto end_nosignal;
 533                         }
 534                 } else {
 535                         ret = consumer_add_channel(new_channel, ctx);
 536                 }
 537                 if (CONSUMER_CHANNEL_TYPE_DATA) {
 538                         consumer_timer_live_start(new_channel,
 539                                         msg.u.channel.live_timer_interval);
 540                 }
 541
 542                 health_code_update();
 543
 544                 /* If we received an error in add_channel, we need to report it. */
 545                 if (ret < 0) {
 546                         ret = consumer_send_status_msg(sock, ret);
 547                         if (ret < 0) {
 548                                 goto error_fatal;
 549                         }
 550                         goto end_nosignal;
 551                 }
 552
 553                 goto end_nosignal;
 554         }
 555         case LTTNG_CONSUMER_ADD_STREAM:
 556         {
 557                 int fd;
 558                 struct lttng_pipe *stream_pipe;
 559                 struct lttng_consumer_stream *new_stream;
 560                 struct lttng_consumer_channel *channel;
 561                 int alloc_ret = 0;
 562
 563                 /*
 564                  * Get stream's channel reference. Needed when adding the stream to the
 565                  * global hash table.
 566                  */
 567                 channel = consumer_find_channel(msg.u.stream.channel_key);
 568                 if (!channel) {
 569                         /*
 570                          * We could not find the channel. Can happen if cpu hotplug
 571                          * happens while tearing down.
 572                          */
 573                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 574                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 575                 }
 576
 577                 health_code_update();
 578
 579                 /* First send a status message before receiving the fds. */
 580                 ret = consumer_send_status_msg(sock, ret_code);
 581                 if (ret < 0) {
 582                         /* Somehow, the session daemon is not responding anymore. */
 583                         goto error_fatal;
 584                 }
 585
 586                 health_code_update();
 587
 588                 if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 589                         /* Channel was not found. */
 590                         goto end_nosignal;
 591                 }
 592
 593                 /* Blocking call */
 594                 health_poll_entry();
 595                 ret = lttng_consumer_poll_socket(consumer_sockpoll);
 596                 health_poll_exit();
 597                 if (ret) {
 598                         goto error_fatal;
 599                 }
 600
 601                 health_code_update();
 602
 603                 /* Get stream file descriptor from socket */
 604                 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 605                 if (ret != sizeof(fd)) {
 606                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 607                         rcu_read_unlock();
 608                         return ret;
 609                 }
 610
 611                 health_code_update();
 612
 613                 /*
 614                  * Send status code to session daemon only if the recv works. If the
 615                  * above recv() failed, the session daemon is notified through the
 616                  * error socket and the teardown is eventually done.
 617                  */
 618                 ret = consumer_send_status_msg(sock, ret_code);
 619                 if (ret < 0) {
 620                         /* Somehow, the session daemon is not responding anymore. */
 621                         goto end_nosignal;
 622                 }
 623
 624                 health_code_update();
 625
 626                 new_stream = consumer_allocate_stream(channel->key,
 627                                 fd,
 628                                 LTTNG_CONSUMER_ACTIVE_STREAM,
 629                                 channel->name,
 630                                 channel->uid,
 631                                 channel->gid,
 632                                 channel->relayd_id,
 633                                 channel->session_id,
 634                                 msg.u.stream.cpu,
 635                                 &alloc_ret,
 636                                 channel->type,
 637                                 channel->monitor);
 638                 if (new_stream == NULL) {
 639                         switch (alloc_ret) {
 640                         case -ENOMEM:
 641                         case -EINVAL:
 642                         default:
 643                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 644                                 break;
 645                         }
 646                         goto end_nosignal;
 647                 }
 648
 649                 new_stream->chan = channel;
 650                 new_stream->wait_fd = fd;
 651                 switch (channel->output) {
 652                 case CONSUMER_CHANNEL_SPLICE:
 653                         new_stream->output = LTTNG_EVENT_SPLICE;
 654                         ret = utils_create_pipe(new_stream->splice_pipe);
 655                         if (ret < 0) {
 656                                 goto end_nosignal;
 657                         }
 658                         break;
 659                 case CONSUMER_CHANNEL_MMAP:
 660                         new_stream->output = LTTNG_EVENT_MMAP;
 661                         break;
 662                 default:
 663                         ERR("Stream output unknown %d", channel->output);
 664                         goto end_nosignal;
 665                 }
 666
 667                 /*
 668                  * We've just assigned the channel to the stream so increment the
 669                  * refcount right now. We don't need to increment the refcount for
 670                  * streams in no monitor because we handle manually the cleanup of
 671                  * those. It is very important to make sure there is NO prior
 672                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 673                  */
 674                 if (channel->monitor) {
 675                         uatomic_inc(&new_stream->chan->refcount);
 676                 }
 677
 678                 /*
 679                  * The buffer flush is done on the session daemon side for the kernel
 680                  * so no need for the stream "hangup_flush_done" variable to be
 681                  * tracked. This is important for a kernel stream since we don't rely
 682                  * on the flush state of the stream to read data. It's not the case for
 683                  * user space tracing.
 684                  */
 685                 new_stream->hangup_flush_done = 0;
 686
 687                 health_code_update();
 688
 689                 if (ctx->on_recv_stream) {
 690                         ret = ctx->on_recv_stream(new_stream);
 691                         if (ret < 0) {
 692                                 consumer_stream_free(new_stream);
 693                                 goto end_nosignal;
 694                         }
 695                 }
 696
 697                 health_code_update();
 698
 699                 if (new_stream->metadata_flag) {
 700                         channel->metadata_stream = new_stream;
 701                 }
 702
 703                 /* Do not monitor this stream. */
 704                 if (!channel->monitor) {
 705                         DBG("Kernel consumer add stream %s in no monitor mode with "
 706                                         "relayd id %" PRIu64, new_stream->name,
 707                                         new_stream->net_seq_idx);
 708                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 709                         break;
 710                 }
 711
 712                 /* Send stream to relayd if the stream has an ID. */
 713                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 714                         ret = consumer_send_relayd_stream(new_stream,
 715                                         new_stream->chan->pathname);
 716                         if (ret < 0) {
 717                                 consumer_stream_free(new_stream);
 718                                 goto end_nosignal;
 719                         }
 720                 }
 721
 722                 /* Get the right pipe where the stream will be sent. */
 723                 if (new_stream->metadata_flag) {
 724                         ret = consumer_add_metadata_stream(new_stream);
 725                         if (ret) {
 726                                 ERR("Consumer add metadata stream %" PRIu64 " failed. Continuing",
 727                                                 new_stream->key);
 728                                 consumer_stream_free(new_stream);
 729                                 goto end_nosignal;
 730                         }
 731                         stream_pipe = ctx->consumer_metadata_pipe;
 732                 } else {
 733                         ret = consumer_add_data_stream(new_stream);
 734                         if (ret) {
 735                                 ERR("Consumer add stream %" PRIu64 " failed. Continuing",
 736                                                 new_stream->key);
 737                                 consumer_stream_free(new_stream);
 738                                 goto end_nosignal;
 739                         }
 740                         stream_pipe = ctx->consumer_data_pipe;
 741                 }
 742
 743                 /* Vitible to other threads */
 744                 new_stream->globally_visible = 1;
 745
 746                 health_code_update();
 747
 748                 ret = lttng_pipe_write(stream_pipe, &new_stream, sizeof(new_stream));
 749                 if (ret < 0) {
 750                         ERR("Consumer write %s stream to pipe %d",
 751                                         new_stream->metadata_flag ? "metadata" : "data",
 752                                         lttng_pipe_get_writefd(stream_pipe));
 753                         if (new_stream->metadata_flag) {
 754                                 consumer_del_stream_for_metadata(new_stream);
 755                         } else {
 756                                 consumer_del_stream_for_data(new_stream);
 757                         }
 758                         goto end_nosignal;
 759                 }
 760
 761                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64,
 762                                 new_stream->name, fd, new_stream->relayd_stream_id);
 763                 break;
 764         }
 765         case LTTNG_CONSUMER_STREAMS_SENT:
 766         {
 767                 struct lttng_consumer_channel *channel;
 768
 769                 /*
 770                  * Get stream's channel reference. Needed when adding the stream to the
 771                  * global hash table.
 772                  */
 773                 channel = consumer_find_channel(msg.u.sent_streams.channel_key);
 774                 if (!channel) {
 775                         /*
 776                          * We could not find the channel. Can happen if cpu hotplug
 777                          * happens while tearing down.
 778                          */
 779                         ERR("Unable to find channel key %" PRIu64,
 780                                         msg.u.sent_streams.channel_key);
 781                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 782                 }
 783
 784                 health_code_update();
 785
 786                 /*
 787                  * Send status code to session daemon.
 788                  */
 789                 ret = consumer_send_status_msg(sock, ret_code);
 790                 if (ret < 0 || ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
 791                         /* Somehow, the session daemon is not responding anymore. */
 792                         goto end_nosignal;
 793                 }
 794
 795                 health_code_update();
 796
 797                 /*
 798                  * We should not send this message if we don't monitor the
 799                  * streams in this channel.
 800                  */
 801                 if (!channel->monitor) {
 802                         break;
 803                 }
 804
 805                 health_code_update();
 806                 /* Send stream to relayd if the stream has an ID. */
 807                 if (msg.u.sent_streams.net_seq_idx != (uint64_t) -1ULL) {
 808                         ret = consumer_send_relayd_streams_sent(
 809                                         msg.u.sent_streams.net_seq_idx);
 810                         if (ret < 0) {
 811                                 goto end_nosignal;
 812                         }
 813                 }
 814                 break;
 815         }
 816         case LTTNG_CONSUMER_UPDATE_STREAM:
 817         {
 818                 rcu_read_unlock();
 819                 return -ENOSYS;
 820         }
 821         case LTTNG_CONSUMER_DESTROY_RELAYD:
 822         {
 823                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 824                 struct consumer_relayd_sock_pair *relayd;
 825
 826                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 827
 828                 /* Get relayd reference if exists. */
 829                 relayd = consumer_find_relayd(index);
 830                 if (relayd == NULL) {
 831                         DBG("Unable to find relayd %" PRIu64, index);
 832                         ret_code = LTTCOMM_CONSUMERD_RELAYD_FAIL;
 833                 }
 834
 835                 /*
 836                  * Each relayd socket pair has a refcount of stream attached to it
 837                  * which tells if the relayd is still active or not depending on the
 838                  * refcount value.
 839                  *
 840                  * This will set the destroy flag of the relayd object and destroy it
 841                  * if the refcount reaches zero when called.
 842                  *
 843                  * The destroy can happen either here or when a stream fd hangs up.
 844                  */
 845                 if (relayd) {
 846                         consumer_flag_relayd_for_destroy(relayd);
 847                 }
 848
 849                 health_code_update();
 850
 851                 ret = consumer_send_status_msg(sock, ret_code);
 852                 if (ret < 0) {
 853                         /* Somehow, the session daemon is not responding anymore. */
 854                         goto error_fatal;
 855                 }
 856
 857                 goto end_nosignal;
 858         }
 859         case LTTNG_CONSUMER_DATA_PENDING:
 860         {
 861                 int32_t ret;
 862                 uint64_t id = msg.u.data_pending.session_id;
 863
 864                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 865
 866                 ret = consumer_data_pending(id);
 867
 868                 health_code_update();
 869
 870                 /* Send back returned value to session daemon */
 871                 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
 872                 if (ret < 0) {
 873                         PERROR("send data pending ret code");
 874                         goto error_fatal;
 875                 }
 876
 877                 /*
 878                  * No need to send back a status message since the data pending
 879                  * returned value is the response.
 880                  */
 881                 break;
 882         }
 883         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 884         {
 885                 if (msg.u.snapshot_channel.metadata == 1) {
 886                         ret = lttng_kconsumer_snapshot_metadata(msg.u.snapshot_channel.key,
 887                                         msg.u.snapshot_channel.pathname,
 888                                         msg.u.snapshot_channel.relayd_id, ctx);
 889                         if (ret < 0) {
 890                                 ERR("Snapshot metadata failed");
 891                                 ret_code = LTTCOMM_CONSUMERD_ERROR_METADATA;
 892                         }
 893                 } else {
 894                         ret = lttng_kconsumer_snapshot_channel(msg.u.snapshot_channel.key,
 895                                         msg.u.snapshot_channel.pathname,
 896                                         msg.u.snapshot_channel.relayd_id,
 897                                         msg.u.snapshot_channel.nb_packets_per_stream,
 898                                         ctx);
 899                         if (ret < 0) {
 900                                 ERR("Snapshot channel failed");
 901                                 ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 902                         }
 903                 }
 904
 905                 health_code_update();
 906
 907                 ret = consumer_send_status_msg(sock, ret_code);
 908                 if (ret < 0) {
 909                         /* Somehow, the session daemon is not responding anymore. */
 910                         goto end_nosignal;
 911                 }
 912                 break;
 913         }
 914         case LTTNG_CONSUMER_DESTROY_CHANNEL:
 915         {
 916                 uint64_t key = msg.u.destroy_channel.key;
 917                 struct lttng_consumer_channel *channel;
 918
 919                 channel = consumer_find_channel(key);
 920                 if (!channel) {
 921                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
 922                         ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
 923                 }
 924
 925                 health_code_update();
 926
 927                 ret = consumer_send_status_msg(sock, ret_code);
 928                 if (ret < 0) {
 929                         /* Somehow, the session daemon is not responding anymore. */
 930                         goto end_nosignal;
 931                 }
 932
 933                 health_code_update();
 934
 935                 /* Stop right now if no channel was found. */
 936                 if (!channel) {
 937                         goto end_nosignal;
 938                 }
 939
 940                 /*
 941                  * This command should ONLY be issued for channel with streams set in
 942                  * no monitor mode.
 943                  */
 944                 assert(!channel->monitor);
 945
 946                 /*
 947                  * The refcount should ALWAYS be 0 in the case of a channel in no
 948                  * monitor mode.
 949                  */
 950                 assert(!uatomic_sub_return(&channel->refcount, 1));
 951
 952                 consumer_del_channel(channel);
 953
 954                 goto end_nosignal;
 955         }
 956         case LTTNG_CONSUMER_DISCARDED_EVENTS:
 957         {
 958                 uint64_t ret;
 959                 struct lttng_consumer_channel *channel;
 960                 uint64_t id = msg.u.discarded_events.session_id;
 961                 uint64_t key = msg.u.discarded_events.channel_key;
 962
 963                 DBG("Kernel consumer discarded events command for session id %"
 964                                 PRIu64 ", channel key %" PRIu64, id, key);
 965
 966                 channel = consumer_find_channel(key);
 967                 if (!channel) {
 968                         ERR("Kernel consumer discarded events channel %"
 969                                         PRIu64 " not found", key);
 970                         ret = 0;
 971                 } else {
 972                         ret = channel->discarded_events;
 973                 }
 974
 975                 health_code_update();
 976
 977                 /* Send back returned value to session daemon */
 978                 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
 979                 if (ret < 0) {
 980                         PERROR("send discarded events");
 981                         goto error_fatal;
 982                 }
 983
 984                 break;
 985         }
 986         case LTTNG_CONSUMER_LOST_PACKETS:
 987         {
 988                 uint64_t ret;
 989                 struct lttng_consumer_channel *channel;
 990                 uint64_t id = msg.u.lost_packets.session_id;
 991                 uint64_t key = msg.u.lost_packets.channel_key;
 992
 993                 DBG("Kernel consumer lost packets command for session id %"
 994                                 PRIu64 ", channel key %" PRIu64, id, key);
 995
 996                 channel = consumer_find_channel(key);
 997                 if (!channel) {
 998                         ERR("Kernel consumer lost packets channel %"
 999                                         PRIu64 " not found", key);
1000                         ret = 0;
1001                 } else {
1002                         ret = channel->lost_packets;
1003                 }
1004
1005                 health_code_update();
1006
1007                 /* Send back returned value to session daemon */
1008                 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
1009                 if (ret < 0) {
1010                         PERROR("send lost packets");
1011                         goto error_fatal;
1012                 }
1013
1014                 break;
1015         }
1016         case LTTNG_CONSUMER_SET_CHANNEL_MONITOR_PIPE:
1017         {
1018                 int channel_monitor_pipe;
1019
1020                 ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1021                 /* Successfully received the command's type. */
1022                 ret = consumer_send_status_msg(sock, ret_code);
1023                 if (ret < 0) {
1024                         goto error_fatal;
1025                 }
1026
1027                 ret = lttcomm_recv_fds_unix_sock(sock, &channel_monitor_pipe,
1028                                 1);
1029                 if (ret != sizeof(channel_monitor_pipe)) {
1030                         ERR("Failed to receive channel monitor pipe");
1031                         goto error_fatal;
1032                 }
1033
1034                 DBG("Received channel monitor pipe (%d)", channel_monitor_pipe);
1035                 ret = consumer_timer_thread_set_channel_monitor_pipe(
1036                                 channel_monitor_pipe);
1037                 if (!ret) {
1038                         int flags;
1039
1040                         ret_code = LTTCOMM_CONSUMERD_SUCCESS;
1041                         /* Set the pipe as non-blocking. */
1042                         ret = fcntl(channel_monitor_pipe, F_GETFL, 0);
1043                         if (ret == -1) {
1044                                 PERROR("fcntl get flags of the channel monitoring pipe");
1045                                 goto error_fatal;
1046                         }
1047                         flags = ret;
1048
1049                         ret = fcntl(channel_monitor_pipe, F_SETFL,
1050                                         flags | O_NONBLOCK);
1051                         if (ret == -1) {
1052                                 PERROR("fcntl set O_NONBLOCK flag of the channel monitoring pipe");
1053                                 goto error_fatal;
1054                         }
1055                         DBG("Channel monitor pipe set as non-blocking");
1056                 } else {
1057                         ret_code = LTTCOMM_CONSUMERD_ALREADY_SET;
1058                 }
1059                 ret = consumer_send_status_msg(sock, ret_code);
1060                 if (ret < 0) {
1061                         goto error_fatal;
1062                 }
1063                 break;
1064         }
1065         default:
1066                 goto end_nosignal;
1067         }
1068
1069 end_nosignal:
1070         rcu_read_unlock();
1071
1072         /*
1073          * Return 1 to indicate success since the 0 value can be a socket
1074          * shutdown during the recv() or send() call.
1075          */
1076         health_code_update();
1077         return 1;
1078
1079 error_fatal:
1080         rcu_read_unlock();
1081         /* This will issue a consumer stop. */
1082         return -1;
1083 }
1084
1085 /*
1086  * Populate index values of a kernel stream. Values are set in big endian order.
1087  *
1088  * Return 0 on success or else a negative value.
1089  */
1090 static int get_index_values(struct ctf_packet_index *index, int infd)
1091 {
1092         int ret;
1093
1094         ret = kernctl_get_timestamp_begin(infd, &index->timestamp_begin);
1095         if (ret < 0) {
1096                 PERROR("kernctl_get_timestamp_begin");
1097                 goto error;
1098         }
1099         index->timestamp_begin = htobe64(index->timestamp_begin);
1100
1101         ret = kernctl_get_timestamp_end(infd, &index->timestamp_end);
1102         if (ret < 0) {
1103                 PERROR("kernctl_get_timestamp_end");
1104                 goto error;
1105         }
1106         index->timestamp_end = htobe64(index->timestamp_end);
1107
1108         ret = kernctl_get_events_discarded(infd, &index->events_discarded);
1109         if (ret < 0) {
1110                 PERROR("kernctl_get_events_discarded");
1111                 goto error;
1112         }
1113         index->events_discarded = htobe64(index->events_discarded);
1114
1115         ret = kernctl_get_content_size(infd, &index->content_size);
1116         if (ret < 0) {
1117                 PERROR("kernctl_get_content_size");
1118                 goto error;
1119         }
1120         index->content_size = htobe64(index->content_size);
1121
1122         ret = kernctl_get_packet_size(infd, &index->packet_size);
1123         if (ret < 0) {
1124                 PERROR("kernctl_get_packet_size");
1125                 goto error;
1126         }
1127         index->packet_size = htobe64(index->packet_size);
1128
1129         ret = kernctl_get_stream_id(infd, &index->stream_id);
1130         if (ret < 0) {
1131                 PERROR("kernctl_get_stream_id");
1132                 goto error;
1133         }
1134         index->stream_id = htobe64(index->stream_id);
1135
1136         ret = kernctl_get_instance_id(infd, &index->stream_instance_id);
1137         if (ret < 0) {
1138                 if (ret == -ENOTTY) {
1139                         /* Command not implemented by lttng-modules. */
1140                         index->stream_instance_id = -1ULL;
1141                         ret = 0;
1142                 } else {
1143                         PERROR("kernctl_get_instance_id");
1144                         goto error;
1145                 }
1146         }
1147         index->stream_instance_id = htobe64(index->stream_instance_id);
1148
1149         ret = kernctl_get_sequence_number(infd, &index->packet_seq_num);
1150         if (ret < 0) {
1151                 if (ret == -ENOTTY) {
1152                         /* Command not implemented by lttng-modules. */
1153                         index->packet_seq_num = -1ULL;
1154                         ret = 0;
1155                 } else {
1156                         PERROR("kernctl_get_sequence_number");
1157                         goto error;
1158                 }
1159         }
1160         index->packet_seq_num = htobe64(index->packet_seq_num);
1161
1162 error:
1163         return ret;
1164 }
1165 /*
1166  * Sync metadata meaning request them to the session daemon and snapshot to the
1167  * metadata thread can consumer them.
1168  *
1169  * Metadata stream lock MUST be acquired.
1170  *
1171  * Return 0 if new metadatda is available, EAGAIN if the metadata stream
1172  * is empty or a negative value on error.
1173  */
1174 int lttng_kconsumer_sync_metadata(struct lttng_consumer_stream *metadata)
1175 {
1176         int ret;
1177
1178         assert(metadata);
1179
1180         ret = kernctl_buffer_flush(metadata->wait_fd);
1181         if (ret < 0) {
1182                 ERR("Failed to flush kernel stream");
1183                 goto end;
1184         }
1185
1186         ret = kernctl_snapshot(metadata->wait_fd);
1187         if (ret < 0) {
1188                 if (ret != -EAGAIN) {
1189                         ERR("Sync metadata, taking kernel snapshot failed.");
1190                         goto end;
1191                 }
1192                 DBG("Sync metadata, no new kernel metadata");
1193                 /* No new metadata, exit. */
1194                 ret = ENODATA;
1195                 goto end;
1196         }
1197
1198 end:
1199         return ret;
1200 }
1201
1202 static
1203 int update_stream_stats(struct lttng_consumer_stream *stream)
1204 {
1205         int ret;
1206         uint64_t seq, discarded;
1207
1208         ret = kernctl_get_sequence_number(stream->wait_fd, &seq);
1209         if (ret < 0) {
1210                 if (ret == -ENOTTY) {
1211                         /* Command not implemented by lttng-modules. */
1212                         seq = -1ULL;
1213                         ret = 0;
1214                 } else {
1215                         PERROR("kernctl_get_sequence_number");
1216                         goto end;
1217                 }
1218         }
1219
1220         /*
1221          * Start the sequence when we extract the first packet in case we don't
1222          * start at 0 (for example if a consumer is not connected to the
1223          * session immediately after the beginning).
1224          */
1225         if (stream->last_sequence_number == -1ULL) {
1226                 stream->last_sequence_number = seq;
1227         } else if (seq > stream->last_sequence_number) {
1228                 stream->chan->lost_packets += seq -
1229                                 stream->last_sequence_number - 1;
1230         } else {
1231                 /* seq <= last_sequence_number */
1232                 ERR("Sequence number inconsistent : prev = %" PRIu64
1233                                 ", current = %" PRIu64,
1234                                 stream->last_sequence_number, seq);
1235                 ret = -1;
1236                 goto end;
1237         }
1238         stream->last_sequence_number = seq;
1239
1240         ret = kernctl_get_events_discarded(stream->wait_fd, &discarded);
1241         if (ret < 0) {
1242                 PERROR("kernctl_get_events_discarded");
1243                 goto end;
1244         }
1245         if (discarded < stream->last_discarded_events) {
1246                 /*
1247                  * Overflow has occurred. We assume only one wrap-around
1248                  * has occurred.
1249                  */
1250                 stream->chan->discarded_events += (1ULL << (CAA_BITS_PER_LONG - 1)) -
1251                         stream->last_discarded_events + discarded;
1252         } else {
1253                 stream->chan->discarded_events += discarded -
1254                         stream->last_discarded_events;
1255         }
1256         stream->last_discarded_events = discarded;
1257         ret = 0;
1258
1259 end:
1260         return ret;
1261 }
1262
1263 /*
1264  * Check if the local version of the metadata stream matches with the version
1265  * of the metadata stream in the kernel. If it was updated, set the reset flag
1266  * on the stream.
1267  */
1268 static
1269 int metadata_stream_check_version(int infd, struct lttng_consumer_stream *stream)
1270 {
1271         int ret;
1272         uint64_t cur_version;
1273
1274         ret = kernctl_get_metadata_version(infd, &cur_version);
1275         if (ret < 0) {
1276                 if (ret == -ENOTTY) {
1277                         /*
1278                          * LTTng-modules does not implement this
1279                          * command.
1280                          */
1281                         ret = 0;
1282                         goto end;
1283                 }
1284                 ERR("Failed to get the metadata version");
1285                 goto end;
1286         }
1287
1288         if (stream->metadata_version == cur_version) {
1289                 ret = 0;
1290                 goto end;
1291         }
1292
1293         DBG("New metadata version detected");
1294         stream->metadata_version = cur_version;
1295         stream->reset_metadata_flag = 1;
1296         ret = 0;
1297
1298 end:
1299         return ret;
1300 }
1301
1302 /*
1303  * Consume data on a file descriptor and write it on a trace file.
1304  */
1305 ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
1306                 struct lttng_consumer_local_data *ctx)
1307 {
1308         unsigned long len, subbuf_size, padding;
1309         int err, write_index = 1;
1310         ssize_t ret = 0;
1311         int infd = stream->wait_fd;
1312         struct ctf_packet_index index;
1313
1314         DBG("In read_subbuffer (infd : %d)", infd);
1315
1316         /* Get the next subbuffer */
1317         err = kernctl_get_next_subbuf(infd);
1318         if (err != 0) {
1319                 /*
1320                  * This is a debug message even for single-threaded consumer,
1321                  * because poll() have more relaxed criterions than get subbuf,
1322                  * so get_subbuf may fail for short race windows where poll()
1323                  * would issue wakeups.
1324                  */
1325                 DBG("Reserving sub buffer failed (everything is normal, "
1326                                 "it is due to concurrency)");
1327                 ret = err;
1328                 goto end;
1329         }
1330
1331         /* Get the full subbuffer size including padding */
1332         err = kernctl_get_padded_subbuf_size(infd, &len);
1333         if (err != 0) {
1334                 PERROR("Getting sub-buffer len failed.");
1335                 err = kernctl_put_subbuf(infd);
1336                 if (err != 0) {
1337                         if (err == -EFAULT) {
1338                                 PERROR("Error in unreserving sub buffer\n");
1339                         } else if (err == -EIO) {
1340                                 /* Should never happen with newer LTTng versions */
1341                                 PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
1342                         }
1343                         ret = err;
1344                         goto end;
1345                 }
1346                 ret = err;
1347                 goto end;
1348         }
1349
1350         if (!stream->metadata_flag) {
1351                 ret = get_index_values(&index, infd);
1352                 if (ret < 0) {
1353                         err = kernctl_put_subbuf(infd);
1354                         if (err != 0) {
1355                                 if (err == -EFAULT) {
1356                                         PERROR("Error in unreserving sub buffer\n");
1357                                 } else if (err == -EIO) {
1358                                         /* Should never happen with newer LTTng versions */
1359                                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
1360                                 }
1361                                 ret = err;
1362                                 goto end;
1363                         }
1364                         goto end;
1365                 }
1366                 ret = update_stream_stats(stream);
1367                 if (ret < 0) {
1368                         err = kernctl_put_subbuf(infd);
1369                         if (err != 0) {
1370                                 if (err == -EFAULT) {
1371                                         PERROR("Error in unreserving sub buffer\n");
1372                                 } else if (err == -EIO) {
1373                                         /* Should never happen with newer LTTng versions */
1374                                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
1375                                 }
1376                                 ret = err;
1377                                 goto end;
1378                         }
1379                         goto end;
1380                 }
1381         } else {
1382                 write_index = 0;
1383                 ret = metadata_stream_check_version(infd, stream);
1384                 if (ret < 0) {
1385                         err = kernctl_put_subbuf(infd);
1386                         if (err != 0) {
1387                                 if (err == -EFAULT) {
1388                                         PERROR("Error in unreserving sub buffer\n");
1389                                 } else if (err == -EIO) {
1390                                         /* Should never happen with newer LTTng versions */
1391                                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
1392                                 }
1393                                 ret = err;
1394                                 goto end;
1395                         }
1396                         goto end;
1397                 }
1398         }
1399
1400         switch (stream->chan->output) {
1401         case CONSUMER_CHANNEL_SPLICE:
1402                 /*
1403                  * XXX: The lttng-modules splice "actor" does not handle copying
1404                  * partial pages hence only using the subbuffer size without the
1405                  * padding makes the splice fail.
1406                  */
1407                 subbuf_size = len;
1408                 padding = 0;
1409
1410                 /* splice the subbuffer to the tracefile */
1411                 ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, subbuf_size,
1412                                 padding, &index);
1413                 /*
1414                  * XXX: Splice does not support network streaming so the return value
1415                  * is simply checked against subbuf_size and not like the mmap() op.
1416                  */
1417                 if (ret != subbuf_size) {
1418                         /*
1419                          * display the error but continue processing to try
1420                          * to release the subbuffer
1421                          */
1422                         ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
1423                                         ret, subbuf_size);
1424                         write_index = 0;
1425                 }
1426                 break;
1427         case CONSUMER_CHANNEL_MMAP:
1428                 /* Get subbuffer size without padding */
1429                 err = kernctl_get_subbuf_size(infd, &subbuf_size);
1430                 if (err != 0) {
1431                         PERROR("Getting sub-buffer len failed.");
1432                         err = kernctl_put_subbuf(infd);
1433                         if (err != 0) {
1434                                 if (err == -EFAULT) {
1435                                         PERROR("Error in unreserving sub buffer\n");
1436                                 } else if (err == -EIO) {
1437                                         /* Should never happen with newer LTTng versions */
1438                                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
1439                                 }
1440                                 ret = err;
1441                                 goto end;
1442                         }
1443                         ret = err;
1444                         goto end;
1445                 }
1446
1447                 /* Make sure the tracer is not gone mad on us! */
1448                 assert(len >= subbuf_size);
1449
1450                 padding = len - subbuf_size;
1451
1452                 /* write the subbuffer to the tracefile */
1453                 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
1454                                 padding, &index);
1455                 /*
1456                  * The mmap operation should write subbuf_size amount of data when
1457                  * network streaming or the full padding (len) size when we are _not_
1458                  * streaming.
1459                  */
1460                 if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
1461                                 (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
1462                         /*
1463                          * Display the error but continue processing to try to release the
1464                          * subbuffer. This is a DBG statement since this is possible to
1465                          * happen without being a critical error.
1466                          */
1467                         DBG("Error writing to tracefile "
1468                                         "(ret: %zd != len: %lu != subbuf_size: %lu)",
1469                                         ret, len, subbuf_size);
1470                         write_index = 0;
1471                 }
1472                 break;
1473         default:
1474                 ERR("Unknown output method");
1475                 ret = -EPERM;
1476         }
1477
1478         err = kernctl_put_next_subbuf(infd);
1479         if (err != 0) {
1480                 if (err == -EFAULT) {
1481                         PERROR("Error in unreserving sub buffer\n");
1482                 } else if (err == -EIO) {
1483                         /* Should never happen with newer LTTng versions */
1484                         PERROR("Reader has been pushed by the writer, last sub-buffer corrupted.");
1485                 }
1486                 ret = err;
1487                 goto end;
1488         }
1489
1490         /* Write index if needed. */
1491         if (!write_index) {
1492                 goto end;
1493         }
1494
1495         if (stream->chan->live_timer_interval && !stream->metadata_flag) {
1496                 /*
1497                  * In live, block until all the metadata is sent.
1498                  */
1499                 pthread_mutex_lock(&stream->metadata_timer_lock);
1500                 assert(!stream->missed_metadata_flush);
1501                 stream->waiting_on_metadata = true;
1502                 pthread_mutex_unlock(&stream->metadata_timer_lock);
1503
1504                 err = consumer_stream_sync_metadata(ctx, stream->session_id);
1505
1506                 pthread_mutex_lock(&stream->metadata_timer_lock);
1507                 stream->waiting_on_metadata = false;
1508                 if (stream->missed_metadata_flush) {
1509                         stream->missed_metadata_flush = false;
1510                         pthread_mutex_unlock(&stream->metadata_timer_lock);
1511                         (void) consumer_flush_kernel_index(stream);
1512                 } else {
1513                         pthread_mutex_unlock(&stream->metadata_timer_lock);
1514                 }
1515                 if (err < 0) {
1516                         goto end;
1517                 }
1518         }
1519
1520         err = consumer_stream_write_index(stream, &index);
1521         if (err < 0) {
1522                 goto end;
1523         }
1524
1525 end:
1526         return ret;
1527 }
1528
1529 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1530 {
1531         int ret;
1532
1533         assert(stream);
1534
1535         /*
1536          * Don't create anything if this is set for streaming or should not be
1537          * monitored.
1538          */
1539         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor) {
1540                 ret = utils_create_stream_file(stream->chan->pathname, stream->name,
1541                                 stream->chan->tracefile_size, stream->tracefile_count_current,
1542                                 stream->uid, stream->gid, NULL);
1543                 if (ret < 0) {
1544                         goto error;
1545                 }
1546                 stream->out_fd = ret;
1547                 stream->tracefile_size_current = 0;
1548
1549                 if (!stream->metadata_flag) {
1550                         struct lttng_index_file *index_file;
1551
1552                         index_file = lttng_index_file_create(stream->chan->pathname,
1553                                         stream->name, stream->uid, stream->gid,
1554                                         stream->chan->tracefile_size,
1555                                         stream->tracefile_count_current,
1556                                         CTF_INDEX_MAJOR, CTF_INDEX_MINOR);
1557                         if (!index_file) {
1558                                 goto error;
1559                         }
1560                         assert(!stream->index_file);
1561                         stream->index_file = index_file;
1562                 }
1563         }
1564
1565         if (stream->output == LTTNG_EVENT_MMAP) {
1566                 /* get the len of the mmap region */
1567                 unsigned long mmap_len;
1568
1569                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1570                 if (ret != 0) {
1571                         PERROR("kernctl_get_mmap_len");
1572                         goto error_close_fd;
1573                 }
1574                 stream->mmap_len = (size_t) mmap_len;
1575
1576                 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
1577                                 MAP_PRIVATE, stream->wait_fd, 0);
1578                 if (stream->mmap_base == MAP_FAILED) {
1579                         PERROR("Error mmaping");
1580                         ret = -1;
1581                         goto error_close_fd;
1582                 }
1583         }
1584
1585         /* we return 0 to let the library handle the FD internally */
1586         return 0;
1587
1588 error_close_fd:
1589         if (stream->out_fd >= 0) {
1590                 int err;
1591
1592                 err = close(stream->out_fd);
1593                 assert(!err);
1594                 stream->out_fd = -1;
1595         }
1596 error:
1597         return ret;
1598 }
1599
1600 /*
1601  * Check if data is still being extracted from the buffers for a specific
1602  * stream. Consumer data lock MUST be acquired before calling this function
1603  * and the stream lock.
1604  *
1605  * Return 1 if the traced data are still getting read else 0 meaning that the
1606  * data is available for trace viewer reading.
1607  */
1608 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1609 {
1610         int ret;
1611
1612         assert(stream);
1613
1614         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1615                 ret = 0;
1616                 goto end;
1617         }
1618
1619         ret = kernctl_get_next_subbuf(stream->wait_fd);
1620         if (ret == 0) {
1621                 /* There is still data so let's put back this subbuffer. */
1622                 ret = kernctl_put_subbuf(stream->wait_fd);
1623                 assert(ret == 0);
1624                 ret = 1;   /* Data is pending */
1625                 goto end;
1626         }
1627
1628         /* Data is NOT pending and ready to be read. */
1629         ret = 0;
1630
1631 end:
1632         return ret;
1633 }