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 _GNU_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 <common/common.h>
  33 #include <common/kernel-ctl/kernel-ctl.h>
  34 #include <common/sessiond-comm/sessiond-comm.h>
  35 #include <common/sessiond-comm/relayd.h>
  36 #include <common/compat/fcntl.h>
  37 #include <common/pipe.h>
  38 #include <common/relayd/relayd.h>
  39 #include <common/utils.h>
  40 #include <common/consumer-stream.h>
  41 #include <common/index/index.h>
  42 #include <common/consumer-timer.h>
  43
  44 #include "kernel-consumer.h"
  45 #include "../../bin/lttng-consumerd/health-consumerd.h"
  46
  47 extern struct lttng_consumer_global_data consumer_data;
  48 extern int consumer_poll_timeout;
  49 extern volatile int consumer_quit;
  50
  51 /*
  52  * Take a snapshot for a specific fd
  53  *
  54  * Returns 0 on success, < 0 on error
  55  */
  56 int lttng_kconsumer_take_snapshot(struct lttng_consumer_stream *stream)
  57 {
  58         int ret = 0;
  59         int infd = stream->wait_fd;
  60
  61         ret = kernctl_snapshot(infd);
  62         if (ret != 0) {
  63                 perror("Getting sub-buffer snapshot.");
  64                 ret = -errno;
  65         }
  66
  67         return ret;
  68 }
  69
  70 /*
  71  * Get the produced position
  72  *
  73  * Returns 0 on success, < 0 on error
  74  */
  75 int lttng_kconsumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
  76                 unsigned long *pos)
  77 {
  78         int ret;
  79         int infd = stream->wait_fd;
  80
  81         ret = kernctl_snapshot_get_produced(infd, pos);
  82         if (ret != 0) {
  83                 perror("kernctl_snapshot_get_produced");
  84                 ret = -errno;
  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                 ret = -errno;
 105         }
 106
 107         return ret;
 108 }
 109
 110 /*
 111  * Take a snapshot of all the stream of a channel
 112  *
 113  * Returns 0 on success, < 0 on error
 114  */
 115 int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
 116                 uint64_t relayd_id, uint64_t max_stream_size,
 117                 struct lttng_consumer_local_data *ctx)
 118 {
 119         int ret;
 120         unsigned long consumed_pos, produced_pos;
 121         struct lttng_consumer_channel *channel;
 122         struct lttng_consumer_stream *stream;
 123
 124         DBG("Kernel consumer snapshot channel %" PRIu64, key);
 125
 126         rcu_read_lock();
 127
 128         channel = consumer_find_channel(key);
 129         if (!channel) {
 130                 ERR("No channel found for key %" PRIu64, key);
 131                 ret = -1;
 132                 goto end;
 133         }
 134
 135         /* Splice is not supported yet for channel snapshot. */
 136         if (channel->output != CONSUMER_CHANNEL_MMAP) {
 137                 ERR("Unsupported output %d", channel->output);
 138                 ret = -1;
 139                 goto end;
 140         }
 141
 142         cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
 143
 144                 health_code_update();
 145
 146                 /*
 147                  * Lock stream because we are about to change its state.
 148                  */
 149                 pthread_mutex_lock(&stream->lock);
 150
 151                 /*
 152                  * Assign the received relayd ID so we can use it for streaming. The streams
 153                  * are not visible to anyone so this is OK to change it.
 154                  */
 155                 stream->net_seq_idx = relayd_id;
 156                 channel->relayd_id = relayd_id;
 157                 if (relayd_id != (uint64_t) -1ULL) {
 158                         ret = consumer_send_relayd_stream(stream, path);
 159                         if (ret < 0) {
 160                                 ERR("sending stream to relayd");
 161                                 goto end_unlock;
 162                         }
 163                 } else {
 164                         ret = utils_create_stream_file(path, stream->name,
 165                                         stream->chan->tracefile_size,
 166                                         stream->tracefile_count_current,
 167                                         stream->uid, stream->gid, NULL);
 168                         if (ret < 0) {
 169                                 ERR("utils_create_stream_file");
 170                                 goto end_unlock;
 171                         }
 172
 173                         stream->out_fd = ret;
 174                         stream->tracefile_size_current = 0;
 175
 176                         DBG("Kernel consumer snapshot stream %s/%s (%" PRIu64 ")",
 177                                         path, stream->name, stream->key);
 178                 }
 179
 180                 ret = kernctl_buffer_flush(stream->wait_fd);
 181                 if (ret < 0) {
 182                         ERR("Failed to flush kernel stream");
 183                         ret = -errno;
 184                         goto end_unlock;
 185                 }
 186
 187                 ret = lttng_kconsumer_take_snapshot(stream);
 188                 if (ret < 0) {
 189                         ERR("Taking kernel snapshot");
 190                         goto end_unlock;
 191                 }
 192
 193                 ret = lttng_kconsumer_get_produced_snapshot(stream, &produced_pos);
 194                 if (ret < 0) {
 195                         ERR("Produced kernel snapshot position");
 196                         goto end_unlock;
 197                 }
 198
 199                 ret = lttng_kconsumer_get_consumed_snapshot(stream, &consumed_pos);
 200                 if (ret < 0) {
 201                         ERR("Consumerd kernel snapshot position");
 202                         goto end_unlock;
 203                 }
 204
 205                 if (stream->max_sb_size == 0) {
 206                         ret = kernctl_get_max_subbuf_size(stream->wait_fd,
 207                                         &stream->max_sb_size);
 208                         if (ret < 0) {
 209                                 ERR("Getting kernel max_sb_size");
 210                                 ret = -errno;
 211                                 goto end_unlock;
 212                         }
 213                 }
 214
 215                 /*
 216                  * The original value is sent back if max stream size is larger than
 217                  * the possible size of the snapshot. Also, we asume that the session
 218                  * daemon should never send a maximum stream size that is lower than
 219                  * subbuffer size.
 220                  */
 221                 consumed_pos = consumer_get_consumed_maxsize(consumed_pos,
 222                                 produced_pos, max_stream_size);
 223
 224                 while (consumed_pos < produced_pos) {
 225                         ssize_t read_len;
 226                         unsigned long len, padded_len;
 227
 228                         health_code_update();
 229
 230                         DBG("Kernel consumer taking snapshot at pos %lu", consumed_pos);
 231
 232                         ret = kernctl_get_subbuf(stream->wait_fd, &consumed_pos);
 233                         if (ret < 0) {
 234                                 if (errno != EAGAIN) {
 235                                         PERROR("kernctl_get_subbuf snapshot");
 236                                         ret = -errno;
 237                                         goto end_unlock;
 238                                 }
 239                                 DBG("Kernel consumer get subbuf failed. Skipping it.");
 240                                 consumed_pos += stream->max_sb_size;
 241                                 continue;
 242                         }
 243
 244                         ret = kernctl_get_subbuf_size(stream->wait_fd, &len);
 245                         if (ret < 0) {
 246                                 ERR("Snapshot kernctl_get_subbuf_size");
 247                                 ret = -errno;
 248                                 goto error_put_subbuf;
 249                         }
 250
 251                         ret = kernctl_get_padded_subbuf_size(stream->wait_fd, &padded_len);
 252                         if (ret < 0) {
 253                                 ERR("Snapshot kernctl_get_padded_subbuf_size");
 254                                 ret = -errno;
 255                                 goto error_put_subbuf;
 256                         }
 257
 258                         read_len = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len,
 259                                         padded_len - len, NULL);
 260                         /*
 261                          * We write the padded len in local tracefiles but the data len
 262                          * when using a relay. Display the error but continue processing
 263                          * to try to release the subbuffer.
 264                          */
 265                         if (relayd_id != (uint64_t) -1ULL) {
 266                                 if (read_len != len) {
 267                                         ERR("Error sending to the relay (ret: %zd != len: %lu)",
 268                                                         read_len, len);
 269                                 }
 270                         } else {
 271                                 if (read_len != padded_len) {
 272                                         ERR("Error writing to tracefile (ret: %zd != len: %lu)",
 273                                                         read_len, padded_len);
 274                                 }
 275                         }
 276
 277                         ret = kernctl_put_subbuf(stream->wait_fd);
 278                         if (ret < 0) {
 279                                 ERR("Snapshot kernctl_put_subbuf");
 280                                 ret = -errno;
 281                                 goto end_unlock;
 282                         }
 283                         consumed_pos += stream->max_sb_size;
 284                 }
 285
 286                 if (relayd_id == (uint64_t) -1ULL) {
 287                         if (stream->out_fd >= 0) {
 288                                 ret = close(stream->out_fd);
 289                                 if (ret < 0) {
 290                                         PERROR("Kernel consumer snapshot close out_fd");
 291                                         goto end_unlock;
 292                                 }
 293                                 stream->out_fd = -1;
 294                         }
 295                 } else {
 296                         close_relayd_stream(stream);
 297                         stream->net_seq_idx = (uint64_t) -1ULL;
 298                 }
 299                 pthread_mutex_unlock(&stream->lock);
 300         }
 301
 302         /* All good! */
 303         ret = 0;
 304         goto end;
 305
 306 error_put_subbuf:
 307         ret = kernctl_put_subbuf(stream->wait_fd);
 308         if (ret < 0) {
 309                 ret = -errno;
 310                 ERR("Snapshot kernctl_put_subbuf error path");
 311         }
 312 end_unlock:
 313         pthread_mutex_unlock(&stream->lock);
 314 end:
 315         rcu_read_unlock();
 316         return ret;
 317 }
 318
 319 /*
 320  * Read the whole metadata available for a snapshot.
 321  *
 322  * Returns 0 on success, < 0 on error
 323  */
 324 int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
 325                 uint64_t relayd_id, struct lttng_consumer_local_data *ctx)
 326 {
 327         int ret, use_relayd = 0;
 328         ssize_t ret_read;
 329         struct lttng_consumer_channel *metadata_channel;
 330         struct lttng_consumer_stream *metadata_stream;
 331
 332         assert(ctx);
 333
 334         DBG("Kernel consumer snapshot metadata with key %" PRIu64 " at path %s",
 335                         key, path);
 336
 337         rcu_read_lock();
 338
 339         metadata_channel = consumer_find_channel(key);
 340         if (!metadata_channel) {
 341                 ERR("Kernel snapshot metadata not found for key %" PRIu64, key);
 342                 ret = -1;
 343                 goto error;
 344         }
 345
 346         metadata_stream = metadata_channel->metadata_stream;
 347         assert(metadata_stream);
 348
 349         /* Flag once that we have a valid relayd for the stream. */
 350         if (relayd_id != (uint64_t) -1ULL) {
 351                 use_relayd = 1;
 352         }
 353
 354         if (use_relayd) {
 355                 ret = consumer_send_relayd_stream(metadata_stream, path);
 356                 if (ret < 0) {
 357                         goto error;
 358                 }
 359         } else {
 360                 ret = utils_create_stream_file(path, metadata_stream->name,
 361                                 metadata_stream->chan->tracefile_size,
 362                                 metadata_stream->tracefile_count_current,
 363                                 metadata_stream->uid, metadata_stream->gid, NULL);
 364                 if (ret < 0) {
 365                         goto error;
 366                 }
 367                 metadata_stream->out_fd = ret;
 368         }
 369
 370         do {
 371                 health_code_update();
 372
 373                 ret_read = lttng_kconsumer_read_subbuffer(metadata_stream, ctx);
 374                 if (ret_read < 0) {
 375                         if (ret_read != -EAGAIN) {
 376                                 ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
 377                                                 ret_read);
 378                                 goto error;
 379                         }
 380                         /* ret_read is negative at this point so we will exit the loop. */
 381                         continue;
 382                 }
 383         } while (ret_read >= 0);
 384
 385         if (use_relayd) {
 386                 close_relayd_stream(metadata_stream);
 387                 metadata_stream->net_seq_idx = (uint64_t) -1ULL;
 388         } else {
 389                 if (metadata_stream->out_fd >= 0) {
 390                         ret = close(metadata_stream->out_fd);
 391                         if (ret < 0) {
 392                                 PERROR("Kernel consumer snapshot metadata close out_fd");
 393                                 /*
 394                                  * Don't go on error here since the snapshot was successful at this
 395                                  * point but somehow the close failed.
 396                                  */
 397                         }
 398                         metadata_stream->out_fd = -1;
 399                 }
 400         }
 401
 402         ret = 0;
 403
 404         cds_list_del(&metadata_stream->send_node);
 405         consumer_stream_destroy(metadata_stream, NULL);
 406         metadata_channel->metadata_stream = NULL;
 407 error:
 408         rcu_read_unlock();
 409         return ret;
 410 }
 411
 412 /*
 413  * Receive command from session daemon and process it.
 414  *
 415  * Return 1 on success else a negative value or 0.
 416  */
 417 int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 418                 int sock, struct pollfd *consumer_sockpoll)
 419 {
 420         ssize_t ret;
 421         enum lttng_error_code ret_code = LTTNG_OK;
 422         struct lttcomm_consumer_msg msg;
 423
 424         health_code_update();
 425
 426         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 427         if (ret != sizeof(msg)) {
 428                 if (ret > 0) {
 429                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_CMD);
 430                         ret = -1;
 431                 }
 432                 return ret;
 433         }
 434
 435         health_code_update();
 436
 437         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 438                 /*
 439                  * Notify the session daemon that the command is completed.
 440                  *
 441                  * On transport layer error, the function call will print an error
 442                  * message so handling the returned code is a bit useless since we
 443                  * return an error code anyway.
 444                  */
 445                 (void) consumer_send_status_msg(sock, ret_code);
 446                 return -ENOENT;
 447         }
 448
 449         health_code_update();
 450
 451         /* relayd needs RCU read-side protection */
 452         rcu_read_lock();
 453
 454         switch (msg.cmd_type) {
 455         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 456         {
 457                 /* Session daemon status message are handled in the following call. */
 458                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 459                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 460                                 &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
 461                                  msg.u.relayd_sock.relayd_session_id);
 462                 goto end_nosignal;
 463         }
 464         case LTTNG_CONSUMER_ADD_CHANNEL:
 465         {
 466                 struct lttng_consumer_channel *new_channel;
 467                 int ret_recv;
 468
 469                 health_code_update();
 470
 471                 /* First send a status message before receiving the fds. */
 472                 ret = consumer_send_status_msg(sock, ret_code);
 473                 if (ret < 0) {
 474                         /* Somehow, the session daemon is not responding anymore. */
 475                         goto error_fatal;
 476                 }
 477
 478                 health_code_update();
 479
 480                 DBG("consumer_add_channel %" PRIu64, msg.u.channel.channel_key);
 481                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 482                                 msg.u.channel.session_id, msg.u.channel.pathname,
 483                                 msg.u.channel.name, msg.u.channel.uid, msg.u.channel.gid,
 484                                 msg.u.channel.relayd_id, msg.u.channel.output,
 485                                 msg.u.channel.tracefile_size,
 486                                 msg.u.channel.tracefile_count, 0,
 487                                 msg.u.channel.monitor,
 488                                 msg.u.channel.live_timer_interval);
 489                 if (new_channel == NULL) {
 490                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 491                         goto end_nosignal;
 492                 }
 493                 new_channel->nb_init_stream_left = msg.u.channel.nb_init_streams;
 494                 switch (msg.u.channel.output) {
 495                 case LTTNG_EVENT_SPLICE:
 496                         new_channel->output = CONSUMER_CHANNEL_SPLICE;
 497                         break;
 498                 case LTTNG_EVENT_MMAP:
 499                         new_channel->output = CONSUMER_CHANNEL_MMAP;
 500                         break;
 501                 default:
 502                         ERR("Channel output unknown %d", msg.u.channel.output);
 503                         goto end_nosignal;
 504                 }
 505
 506                 /* Translate and save channel type. */
 507                 switch (msg.u.channel.type) {
 508                 case CONSUMER_CHANNEL_TYPE_DATA:
 509                 case CONSUMER_CHANNEL_TYPE_METADATA:
 510                         new_channel->type = msg.u.channel.type;
 511                         break;
 512                 default:
 513                         assert(0);
 514                         goto end_nosignal;
 515                 };
 516
 517                 health_code_update();
 518
 519                 if (ctx->on_recv_channel != NULL) {
 520                         ret_recv = ctx->on_recv_channel(new_channel);
 521                         if (ret_recv == 0) {
 522                                 ret = consumer_add_channel(new_channel, ctx);
 523                         } else if (ret_recv < 0) {
 524                                 goto end_nosignal;
 525                         }
 526                 } else {
 527                         ret = consumer_add_channel(new_channel, ctx);
 528                 }
 529                 if (CONSUMER_CHANNEL_TYPE_DATA) {
 530                         consumer_timer_live_start(new_channel,
 531                                         msg.u.channel.live_timer_interval);
 532                 }
 533
 534                 health_code_update();
 535
 536                 /* If we received an error in add_channel, we need to report it. */
 537                 if (ret < 0) {
 538                         ret = consumer_send_status_msg(sock, ret);
 539                         if (ret < 0) {
 540                                 goto error_fatal;
 541                         }
 542                         goto end_nosignal;
 543                 }
 544
 545                 goto end_nosignal;
 546         }
 547         case LTTNG_CONSUMER_ADD_STREAM:
 548         {
 549                 int fd;
 550                 struct lttng_pipe *stream_pipe;
 551                 struct lttng_consumer_stream *new_stream;
 552                 struct lttng_consumer_channel *channel;
 553                 int alloc_ret = 0;
 554
 555                 /*
 556                  * Get stream's channel reference. Needed when adding the stream to the
 557                  * global hash table.
 558                  */
 559                 channel = consumer_find_channel(msg.u.stream.channel_key);
 560                 if (!channel) {
 561                         /*
 562                          * We could not find the channel. Can happen if cpu hotplug
 563                          * happens while tearing down.
 564                          */
 565                         ERR("Unable to find channel key %" PRIu64, msg.u.stream.channel_key);
 566                         ret_code = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 567                 }
 568
 569                 health_code_update();
 570
 571                 /* First send a status message before receiving the fds. */
 572                 ret = consumer_send_status_msg(sock, ret_code);
 573                 if (ret < 0) {
 574                         /* Somehow, the session daemon is not responding anymore. */
 575                         goto error_fatal;
 576                 }
 577
 578                 health_code_update();
 579
 580                 if (ret_code != LTTNG_OK) {
 581                         /* Channel was not found. */
 582                         goto end_nosignal;
 583                 }
 584
 585                 /* Blocking call */
 586                 health_poll_entry();
 587                 ret = lttng_consumer_poll_socket(consumer_sockpoll);
 588                 health_poll_exit();
 589                 if (ret < 0) {
 590                         rcu_read_unlock();
 591                         return -EINTR;
 592                 }
 593
 594                 health_code_update();
 595
 596                 /* Get stream file descriptor from socket */
 597                 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 598                 if (ret != sizeof(fd)) {
 599                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 600                         rcu_read_unlock();
 601                         return ret;
 602                 }
 603
 604                 health_code_update();
 605
 606                 /*
 607                  * Send status code to session daemon only if the recv works. If the
 608                  * above recv() failed, the session daemon is notified through the
 609                  * error socket and the teardown is eventually done.
 610                  */
 611                 ret = consumer_send_status_msg(sock, ret_code);
 612                 if (ret < 0) {
 613                         /* Somehow, the session daemon is not responding anymore. */
 614                         goto end_nosignal;
 615                 }
 616
 617                 health_code_update();
 618
 619                 new_stream = consumer_allocate_stream(channel->key,
 620                                 fd,
 621                                 LTTNG_CONSUMER_ACTIVE_STREAM,
 622                                 channel->name,
 623                                 channel->uid,
 624                                 channel->gid,
 625                                 channel->relayd_id,
 626                                 channel->session_id,
 627                                 msg.u.stream.cpu,
 628                                 &alloc_ret,
 629                                 channel->type,
 630                                 channel->monitor);
 631                 if (new_stream == NULL) {
 632                         switch (alloc_ret) {
 633                         case -ENOMEM:
 634                         case -EINVAL:
 635                         default:
 636                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 637                                 break;
 638                         }
 639                         goto end_nosignal;
 640                 }
 641
 642                 new_stream->chan = channel;
 643                 new_stream->wait_fd = fd;
 644                 switch (channel->output) {
 645                 case CONSUMER_CHANNEL_SPLICE:
 646                         new_stream->output = LTTNG_EVENT_SPLICE;
 647                         break;
 648                 case CONSUMER_CHANNEL_MMAP:
 649                         new_stream->output = LTTNG_EVENT_MMAP;
 650                         break;
 651                 default:
 652                         ERR("Stream output unknown %d", channel->output);
 653                         goto end_nosignal;
 654                 }
 655
 656                 /*
 657                  * We've just assigned the channel to the stream so increment the
 658                  * refcount right now. We don't need to increment the refcount for
 659                  * streams in no monitor because we handle manually the cleanup of
 660                  * those. It is very important to make sure there is NO prior
 661                  * consumer_del_stream() calls or else the refcount will be unbalanced.
 662                  */
 663                 if (channel->monitor) {
 664                         uatomic_inc(&new_stream->chan->refcount);
 665                 }
 666
 667                 /*
 668                  * The buffer flush is done on the session daemon side for the kernel
 669                  * so no need for the stream "hangup_flush_done" variable to be
 670                  * tracked. This is important for a kernel stream since we don't rely
 671                  * on the flush state of the stream to read data. It's not the case for
 672                  * user space tracing.
 673                  */
 674                 new_stream->hangup_flush_done = 0;
 675
 676                 health_code_update();
 677
 678                 if (ctx->on_recv_stream) {
 679                         ret = ctx->on_recv_stream(new_stream);
 680                         if (ret < 0) {
 681                                 consumer_stream_free(new_stream);
 682                                 goto end_nosignal;
 683                         }
 684                 }
 685
 686                 health_code_update();
 687
 688                 if (new_stream->metadata_flag) {
 689                         channel->metadata_stream = new_stream;
 690                 }
 691
 692                 /* Do not monitor this stream. */
 693                 if (!channel->monitor) {
 694                         DBG("Kernel consumer add stream %s in no monitor mode with "
 695                                         "relayd id %" PRIu64, new_stream->name,
 696                                         new_stream->net_seq_idx);
 697                         cds_list_add(&new_stream->send_node, &channel->streams.head);
 698                         break;
 699                 }
 700
 701                 /* Send stream to relayd if the stream has an ID. */
 702                 if (new_stream->net_seq_idx != (uint64_t) -1ULL) {
 703                         ret = consumer_send_relayd_stream(new_stream,
 704                                         new_stream->chan->pathname);
 705                         if (ret < 0) {
 706                                 consumer_stream_free(new_stream);
 707                                 goto end_nosignal;
 708                         }
 709                 }
 710
 711                 /* Get the right pipe where the stream will be sent. */
 712                 if (new_stream->metadata_flag) {
 713                         ret = consumer_add_metadata_stream(new_stream);
 714                         if (ret) {
 715                                 ERR("Consumer add metadata stream %" PRIu64 " failed. Continuing",
 716                                                 new_stream->key);
 717                                 consumer_stream_free(new_stream);
 718                                 goto end_nosignal;
 719                         }
 720                         stream_pipe = ctx->consumer_metadata_pipe;
 721                 } else {
 722                         ret = consumer_add_data_stream(new_stream);
 723                         if (ret) {
 724                                 ERR("Consumer add stream %" PRIu64 " failed. Continuing",
 725                                                 new_stream->key);
 726                                 consumer_stream_free(new_stream);
 727                                 goto end_nosignal;
 728                         }
 729                         stream_pipe = ctx->consumer_data_pipe;
 730                 }
 731
 732                 /* Vitible to other threads */
 733                 new_stream->globally_visible = 1;
 734
 735                 health_code_update();
 736
 737                 ret = lttng_pipe_write(stream_pipe, &new_stream, sizeof(new_stream));
 738                 if (ret < 0) {
 739                         ERR("Consumer write %s stream to pipe %d",
 740                                         new_stream->metadata_flag ? "metadata" : "data",
 741                                         lttng_pipe_get_writefd(stream_pipe));
 742                         if (new_stream->metadata_flag) {
 743                                 consumer_del_stream_for_metadata(new_stream);
 744                         } else {
 745                                 consumer_del_stream_for_data(new_stream);
 746                         }
 747                         goto end_nosignal;
 748                 }
 749
 750                 DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64,
 751                                 new_stream->name, fd, new_stream->relayd_stream_id);
 752                 break;
 753         }
 754         case LTTNG_CONSUMER_UPDATE_STREAM:
 755         {
 756                 rcu_read_unlock();
 757                 return -ENOSYS;
 758         }
 759         case LTTNG_CONSUMER_DESTROY_RELAYD:
 760         {
 761                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 762                 struct consumer_relayd_sock_pair *relayd;
 763
 764                 DBG("Kernel consumer destroying relayd %" PRIu64, index);
 765
 766                 /* Get relayd reference if exists. */
 767                 relayd = consumer_find_relayd(index);
 768                 if (relayd == NULL) {
 769                         DBG("Unable to find relayd %" PRIu64, index);
 770                         ret_code = LTTNG_ERR_NO_CONSUMER;
 771                 }
 772
 773                 /*
 774                  * Each relayd socket pair has a refcount of stream attached to it
 775                  * which tells if the relayd is still active or not depending on the
 776                  * refcount value.
 777                  *
 778                  * This will set the destroy flag of the relayd object and destroy it
 779                  * if the refcount reaches zero when called.
 780                  *
 781                  * The destroy can happen either here or when a stream fd hangs up.
 782                  */
 783                 if (relayd) {
 784                         consumer_flag_relayd_for_destroy(relayd);
 785                 }
 786
 787                 health_code_update();
 788
 789                 ret = consumer_send_status_msg(sock, ret_code);
 790                 if (ret < 0) {
 791                         /* Somehow, the session daemon is not responding anymore. */
 792                         goto error_fatal;
 793                 }
 794
 795                 goto end_nosignal;
 796         }
 797         case LTTNG_CONSUMER_DATA_PENDING:
 798         {
 799                 int32_t ret;
 800                 uint64_t id = msg.u.data_pending.session_id;
 801
 802                 DBG("Kernel consumer data pending command for id %" PRIu64, id);
 803
 804                 ret = consumer_data_pending(id);
 805
 806                 health_code_update();
 807
 808                 /* Send back returned value to session daemon */
 809                 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
 810                 if (ret < 0) {
 811                         PERROR("send data pending ret code");
 812                         goto error_fatal;
 813                 }
 814
 815                 /*
 816                  * No need to send back a status message since the data pending
 817                  * returned value is the response.
 818                  */
 819                 break;
 820         }
 821         case LTTNG_CONSUMER_SNAPSHOT_CHANNEL:
 822         {
 823                 if (msg.u.snapshot_channel.metadata == 1) {
 824                         ret = lttng_kconsumer_snapshot_metadata(msg.u.snapshot_channel.key,
 825                                         msg.u.snapshot_channel.pathname,
 826                                         msg.u.snapshot_channel.relayd_id, ctx);
 827                         if (ret < 0) {
 828                                 ERR("Snapshot metadata failed");
 829                                 ret_code = LTTNG_ERR_KERN_META_FAIL;
 830                         }
 831                 } else {
 832                         ret = lttng_kconsumer_snapshot_channel(msg.u.snapshot_channel.key,
 833                                         msg.u.snapshot_channel.pathname,
 834                                         msg.u.snapshot_channel.relayd_id,
 835                                         msg.u.snapshot_channel.max_stream_size,
 836                                         ctx);
 837                         if (ret < 0) {
 838                                 ERR("Snapshot channel failed");
 839                                 ret_code = LTTNG_ERR_KERN_CHAN_FAIL;
 840                         }
 841                 }
 842
 843                 health_code_update();
 844
 845                 ret = consumer_send_status_msg(sock, ret_code);
 846                 if (ret < 0) {
 847                         /* Somehow, the session daemon is not responding anymore. */
 848                         goto end_nosignal;
 849                 }
 850                 break;
 851         }
 852         case LTTNG_CONSUMER_DESTROY_CHANNEL:
 853         {
 854                 uint64_t key = msg.u.destroy_channel.key;
 855                 struct lttng_consumer_channel *channel;
 856
 857                 channel = consumer_find_channel(key);
 858                 if (!channel) {
 859                         ERR("Kernel consumer destroy channel %" PRIu64 " not found", key);
 860                         ret_code = LTTNG_ERR_KERN_CHAN_NOT_FOUND;
 861                 }
 862
 863                 health_code_update();
 864
 865                 ret = consumer_send_status_msg(sock, ret_code);
 866                 if (ret < 0) {
 867                         /* Somehow, the session daemon is not responding anymore. */
 868                         goto end_nosignal;
 869                 }
 870
 871                 health_code_update();
 872
 873                 /*
 874                  * This command should ONLY be issued for channel with streams set in
 875                  * no monitor mode.
 876                  */
 877                 assert(!channel->monitor);
 878
 879                 /*
 880                  * The refcount should ALWAYS be 0 in the case of a channel in no
 881                  * monitor mode.
 882                  */
 883                 assert(!uatomic_sub_return(&channel->refcount, 1));
 884
 885                 consumer_del_channel(channel);
 886
 887                 goto end_nosignal;
 888         }
 889         default:
 890                 goto end_nosignal;
 891         }
 892
 893 end_nosignal:
 894         rcu_read_unlock();
 895
 896         /*
 897          * Return 1 to indicate success since the 0 value can be a socket
 898          * shutdown during the recv() or send() call.
 899          */
 900         health_code_update();
 901         return 1;
 902
 903 error_fatal:
 904         rcu_read_unlock();
 905         /* This will issue a consumer stop. */
 906         return -1;
 907 }
 908
 909 /*
 910  * Populate index values of a kernel stream. Values are set in big endian order.
 911  *
 912  * Return 0 on success or else a negative value.
 913  */
 914 static int get_index_values(struct lttng_packet_index *index, int infd)
 915 {
 916         int ret;
 917
 918         ret = kernctl_get_timestamp_begin(infd, &index->timestamp_begin);
 919         if (ret < 0) {
 920                 PERROR("kernctl_get_timestamp_begin");
 921                 goto error;
 922         }
 923         index->timestamp_begin = htobe64(index->timestamp_begin);
 924
 925         ret = kernctl_get_timestamp_end(infd, &index->timestamp_end);
 926         if (ret < 0) {
 927                 PERROR("kernctl_get_timestamp_end");
 928                 goto error;
 929         }
 930         index->timestamp_end = htobe64(index->timestamp_end);
 931
 932         ret = kernctl_get_events_discarded(infd, &index->events_discarded);
 933         if (ret < 0) {
 934                 PERROR("kernctl_get_events_discarded");
 935                 goto error;
 936         }
 937         index->events_discarded = htobe64(index->events_discarded);
 938
 939         ret = kernctl_get_content_size(infd, &index->content_size);
 940         if (ret < 0) {
 941                 PERROR("kernctl_get_content_size");
 942                 goto error;
 943         }
 944         index->content_size = htobe64(index->content_size);
 945
 946         ret = kernctl_get_packet_size(infd, &index->packet_size);
 947         if (ret < 0) {
 948                 PERROR("kernctl_get_packet_size");
 949                 goto error;
 950         }
 951         index->packet_size = htobe64(index->packet_size);
 952
 953         ret = kernctl_get_stream_id(infd, &index->stream_id);
 954         if (ret < 0) {
 955                 PERROR("kernctl_get_stream_id");
 956                 goto error;
 957         }
 958         index->stream_id = htobe64(index->stream_id);
 959
 960 error:
 961         return ret;
 962 }
 963 /*
 964  * Sync metadata meaning request them to the session daemon and snapshot to the
 965  * metadata thread can consumer them.
 966  *
 967  * Metadata stream lock MUST be acquired.
 968  *
 969  * Return 0 if new metadatda is available, EAGAIN if the metadata stream
 970  * is empty or a negative value on error.
 971  */
 972 int lttng_kconsumer_sync_metadata(struct lttng_consumer_stream *metadata)
 973 {
 974         int ret;
 975
 976         assert(metadata);
 977
 978         ret = kernctl_buffer_flush(metadata->wait_fd);
 979         if (ret < 0) {
 980                 ERR("Failed to flush kernel stream");
 981                 goto end;
 982         }
 983
 984         ret = kernctl_snapshot(metadata->wait_fd);
 985         if (ret < 0) {
 986                 if (errno != EAGAIN) {
 987                         ERR("Sync metadata, taking kernel snapshot failed.");
 988                         goto end;
 989                 }
 990                 DBG("Sync metadata, no new kernel metadata");
 991                 /* No new metadata, exit. */
 992                 ret = ENODATA;
 993                 goto end;
 994         }
 995
 996 end:
 997         return ret;
 998 }
 999
1000 /*
1001  * Consume data on a file descriptor and write it on a trace file.
1002  */
1003 ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
1004                 struct lttng_consumer_local_data *ctx)
1005 {
1006         unsigned long len, subbuf_size, padding;
1007         int err, write_index = 1;
1008         ssize_t ret = 0;
1009         int infd = stream->wait_fd;
1010         struct lttng_packet_index index;
1011
1012         DBG("In read_subbuffer (infd : %d)", infd);
1013
1014         /* Get the next subbuffer */
1015         err = kernctl_get_next_subbuf(infd);
1016         if (err != 0) {
1017                 /*
1018                  * This is a debug message even for single-threaded consumer,
1019                  * because poll() have more relaxed criterions than get subbuf,
1020                  * so get_subbuf may fail for short race windows where poll()
1021                  * would issue wakeups.
1022                  */
1023                 DBG("Reserving sub buffer failed (everything is normal, "
1024                                 "it is due to concurrency)");
1025                 ret = -errno;
1026                 goto end;
1027         }
1028
1029         /* Get the full subbuffer size including padding */
1030         err = kernctl_get_padded_subbuf_size(infd, &len);
1031         if (err != 0) {
1032                 perror("Getting sub-buffer len failed.");
1033                 ret = -errno;
1034                 goto end;
1035         }
1036
1037         if (!stream->metadata_flag) {
1038                 ret = get_index_values(&index, infd);
1039                 if (ret < 0) {
1040                         goto end;
1041                 }
1042         } else {
1043                 write_index = 0;
1044         }
1045
1046         switch (stream->chan->output) {
1047         case CONSUMER_CHANNEL_SPLICE:
1048                 /*
1049                  * XXX: The lttng-modules splice "actor" does not handle copying
1050                  * partial pages hence only using the subbuffer size without the
1051                  * padding makes the splice fail.
1052                  */
1053                 subbuf_size = len;
1054                 padding = 0;
1055
1056                 /* splice the subbuffer to the tracefile */
1057                 ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, subbuf_size,
1058                                 padding, &index);
1059                 /*
1060                  * XXX: Splice does not support network streaming so the return value
1061                  * is simply checked against subbuf_size and not like the mmap() op.
1062                  */
1063                 if (ret != subbuf_size) {
1064                         /*
1065                          * display the error but continue processing to try
1066                          * to release the subbuffer
1067                          */
1068                         ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
1069                                         ret, subbuf_size);
1070                         write_index = 0;
1071                 }
1072                 break;
1073         case CONSUMER_CHANNEL_MMAP:
1074                 /* Get subbuffer size without padding */
1075                 err = kernctl_get_subbuf_size(infd, &subbuf_size);
1076                 if (err != 0) {
1077                         perror("Getting sub-buffer len failed.");
1078                         ret = -errno;
1079                         goto end;
1080                 }
1081
1082                 /* Make sure the tracer is not gone mad on us! */
1083                 assert(len >= subbuf_size);
1084
1085                 padding = len - subbuf_size;
1086
1087                 /* write the subbuffer to the tracefile */
1088                 ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
1089                                 padding, &index);
1090                 /*
1091                  * The mmap operation should write subbuf_size amount of data when
1092                  * network streaming or the full padding (len) size when we are _not_
1093                  * streaming.
1094                  */
1095                 if ((ret != subbuf_size && stream->net_seq_idx != (uint64_t) -1ULL) ||
1096                                 (ret != len && stream->net_seq_idx == (uint64_t) -1ULL)) {
1097                         /*
1098                          * Display the error but continue processing to try to release the
1099                          * subbuffer
1100                          */
1101                         ERR("Error writing to tracefile "
1102                                         "(ret: %zd != len: %lu != subbuf_size: %lu)",
1103                                         ret, len, subbuf_size);
1104                         write_index = 0;
1105                 }
1106                 break;
1107         default:
1108                 ERR("Unknown output method");
1109                 ret = -EPERM;
1110         }
1111
1112         err = kernctl_put_next_subbuf(infd);
1113         if (err != 0) {
1114                 if (errno == EFAULT) {
1115                         perror("Error in unreserving sub buffer\n");
1116                 } else if (errno == EIO) {
1117                         /* Should never happen with newer LTTng versions */
1118                         perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
1119                 }
1120                 ret = -errno;
1121                 goto end;
1122         }
1123
1124         /* Write index if needed. */
1125         if (!write_index) {
1126                 goto end;
1127         }
1128
1129         if (stream->chan->live_timer_interval && !stream->metadata_flag) {
1130                 /*
1131                  * In live, block until all the metadata is sent.
1132                  */
1133                 err = consumer_stream_sync_metadata(ctx, stream->session_id);
1134                 if (err < 0) {
1135                         goto end;
1136                 }
1137         }
1138
1139         err = consumer_stream_write_index(stream, &index);
1140         if (err < 0) {
1141                 goto end;
1142         }
1143
1144 end:
1145         return ret;
1146 }
1147
1148 int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
1149 {
1150         int ret;
1151
1152         assert(stream);
1153
1154         /*
1155          * Don't create anything if this is set for streaming or should not be
1156          * monitored.
1157          */
1158         if (stream->net_seq_idx == (uint64_t) -1ULL && stream->chan->monitor) {
1159                 ret = utils_create_stream_file(stream->chan->pathname, stream->name,
1160                                 stream->chan->tracefile_size, stream->tracefile_count_current,
1161                                 stream->uid, stream->gid, NULL);
1162                 if (ret < 0) {
1163                         goto error;
1164                 }
1165                 stream->out_fd = ret;
1166                 stream->tracefile_size_current = 0;
1167
1168                 if (!stream->metadata_flag) {
1169                         ret = index_create_file(stream->chan->pathname,
1170                                         stream->name, stream->uid, stream->gid,
1171                                         stream->chan->tracefile_size,
1172                                         stream->tracefile_count_current);
1173                         if (ret < 0) {
1174                                 goto error;
1175                         }
1176                         stream->index_fd = ret;
1177                 }
1178         }
1179
1180         if (stream->output == LTTNG_EVENT_MMAP) {
1181                 /* get the len of the mmap region */
1182                 unsigned long mmap_len;
1183
1184                 ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
1185                 if (ret != 0) {
1186                         PERROR("kernctl_get_mmap_len");
1187                         ret = -errno;
1188                         goto error_close_fd;
1189                 }
1190                 stream->mmap_len = (size_t) mmap_len;
1191
1192                 stream->mmap_base = mmap(NULL, stream->mmap_len, PROT_READ,
1193                                 MAP_PRIVATE, stream->wait_fd, 0);
1194                 if (stream->mmap_base == MAP_FAILED) {
1195                         PERROR("Error mmaping");
1196                         ret = -1;
1197                         goto error_close_fd;
1198                 }
1199         }
1200
1201         /* we return 0 to let the library handle the FD internally */
1202         return 0;
1203
1204 error_close_fd:
1205         if (stream->out_fd >= 0) {
1206                 int err;
1207
1208                 err = close(stream->out_fd);
1209                 assert(!err);
1210                 stream->out_fd = -1;
1211         }
1212 error:
1213         return ret;
1214 }
1215
1216 /*
1217  * Check if data is still being extracted from the buffers for a specific
1218  * stream. Consumer data lock MUST be acquired before calling this function
1219  * and the stream lock.
1220  *
1221  * Return 1 if the traced data are still getting read else 0 meaning that the
1222  * data is available for trace viewer reading.
1223  */
1224 int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
1225 {
1226         int ret;
1227
1228         assert(stream);
1229
1230         if (stream->endpoint_status != CONSUMER_ENDPOINT_ACTIVE) {
1231                 ret = 0;
1232                 goto end;
1233         }
1234
1235         ret = kernctl_get_next_subbuf(stream->wait_fd);
1236         if (ret == 0) {
1237                 /* There is still data so let's put back this subbuffer. */
1238                 ret = kernctl_put_subbuf(stream->wait_fd);
1239                 assert(ret == 0);
1240                 ret = 1;   /* Data is pending */
1241                 goto end;
1242         }
1243
1244         /* Data is NOT pending and ready to be read. */
1245         ret = 0;
1246
1247 end:
1248         return ret;
1249 }