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