src/common/consumer/consumer.h

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *               2012 - David Goulet <dgoulet@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifndef LIB_CONSUMER_H
  21 #define LIB_CONSUMER_H
  22
  23 #include <limits.h>
  24 #include <poll.h>
  25 #include <unistd.h>
  26 #include <urcu/list.h>
  27
  28 #include <lttng/lttng.h>
  29
  30 #include <common/hashtable/hashtable.h>
  31 #include <common/compat/fcntl.h>
  32 #include <common/compat/uuid.h>
  33 #include <common/sessiond-comm/sessiond-comm.h>
  34 #include <common/pipe.h>
  35 #include <common/index/ctf-index.h>
  36 #include <common/buffer-view.h>
  37 #include <common/optional.h>
  38
  39 struct lttng_consumer_local_data;
  40
  41 /* Commands for consumer */
  42 enum lttng_consumer_command {
  43         LTTNG_CONSUMER_ADD_CHANNEL,
  44         LTTNG_CONSUMER_ADD_STREAM,
  45         /* pause, delete, active depending on fd state */
  46         LTTNG_CONSUMER_UPDATE_STREAM,
  47         /* inform the consumer to quit when all fd has hang up */
  48         LTTNG_CONSUMER_STOP,    /* deprecated */
  49         LTTNG_CONSUMER_ADD_RELAYD_SOCKET,
  50         /* Inform the consumer to kill a specific relayd connection */
  51         LTTNG_CONSUMER_DESTROY_RELAYD,
  52         /* Return to the sessiond if there is data pending for a session */
  53         LTTNG_CONSUMER_DATA_PENDING,
  54         /* Consumer creates a channel and returns it to sessiond. */
  55         LTTNG_CONSUMER_ASK_CHANNEL_CREATION,
  56         LTTNG_CONSUMER_GET_CHANNEL,
  57         LTTNG_CONSUMER_DESTROY_CHANNEL,
  58         LTTNG_CONSUMER_PUSH_METADATA,
  59         LTTNG_CONSUMER_CLOSE_METADATA,
  60         LTTNG_CONSUMER_SETUP_METADATA,
  61         LTTNG_CONSUMER_FLUSH_CHANNEL,
  62         LTTNG_CONSUMER_SNAPSHOT_CHANNEL,
  63         LTTNG_CONSUMER_SNAPSHOT_METADATA,
  64         LTTNG_CONSUMER_STREAMS_SENT,
  65         LTTNG_CONSUMER_DISCARDED_EVENTS,
  66         LTTNG_CONSUMER_LOST_PACKETS,
  67         LTTNG_CONSUMER_CLEAR_QUIESCENT_CHANNEL,
  68 };
  69
  70 /* State of each fd in consumer */
  71 enum lttng_consumer_stream_state {
  72         LTTNG_CONSUMER_ACTIVE_STREAM,
  73         LTTNG_CONSUMER_PAUSE_STREAM,
  74         LTTNG_CONSUMER_DELETE_STREAM,
  75 };
  76
  77 enum lttng_consumer_type {
  78         LTTNG_CONSUMER_UNKNOWN = 0,
  79         LTTNG_CONSUMER_KERNEL,
  80         LTTNG_CONSUMER64_UST,
  81         LTTNG_CONSUMER32_UST,
  82 };
  83
  84 enum consumer_endpoint_status {
  85         CONSUMER_ENDPOINT_ACTIVE,
  86         CONSUMER_ENDPOINT_INACTIVE,
  87 };
  88
  89 enum consumer_channel_output {
  90         CONSUMER_CHANNEL_MMAP   = 0,
  91         CONSUMER_CHANNEL_SPLICE = 1,
  92 };
  93
  94 enum consumer_channel_type {
  95         CONSUMER_CHANNEL_TYPE_METADATA  = 0,
  96         CONSUMER_CHANNEL_TYPE_DATA      = 1,
  97 };
  98
  99 extern struct lttng_consumer_global_data consumer_data;
 100
 101 struct stream_list {
 102         struct cds_list_head head;
 103         unsigned int count;
 104 };
 105
 106 /* Stub. */
 107 struct consumer_metadata_cache;
 108
 109 struct lttng_consumer_channel {
 110         /* HT node used for consumer_data.channel_ht */
 111         struct lttng_ht_node_u64 node;
 112         /* Indexed key. Incremented value in the consumer. */
 113         uint64_t key;
 114         /* Number of streams referencing this channel */
 115         int refcount;
 116         /* Tracing session id on the session daemon side. */
 117         uint64_t session_id;
 118         /*
 119          * Session id when requesting metadata to the session daemon for
 120          * a session with per-PID buffers.
 121          */
 122         uint64_t session_id_per_pid;
 123         /* Channel trace file path name. */
 124         char pathname[PATH_MAX];
 125         /* Channel name. */
 126         char name[LTTNG_SYMBOL_NAME_LEN];
 127         /* UID and GID of the session owning this channel. */
 128         uid_t uid;
 129         gid_t gid;
 130         /* Relayd id of the channel. -1ULL if it does not apply. */
 131         uint64_t relayd_id;
 132         /*
 133          * Number of streams NOT initialized yet. This is used in order to not
 134          * delete this channel if streams are getting initialized.
 135          */
 136         unsigned int nb_init_stream_left;
 137         /* Output type (mmap or splice). */
 138         enum consumer_channel_output output;
 139         /* Channel type for stream */
 140         enum consumer_channel_type type;
 141
 142         /* For UST */
 143         uid_t ust_app_uid;      /* Application UID. */
 144         struct ustctl_consumer_channel *uchan;
 145         unsigned char uuid[UUID_STR_LEN];
 146         /*
 147          * Temporary stream list used to store the streams once created and waiting
 148          * to be sent to the session daemon by receiving the
 149          * LTTNG_CONSUMER_GET_CHANNEL.
 150          */
 151         struct stream_list streams;
 152
 153         /*
 154          * Set if the channel is metadata. We keep a reference to the stream
 155          * because we have to flush data once pushed by the session daemon. For a
 156          * regular channel, this is always set to NULL.
 157          */
 158         struct lttng_consumer_stream *metadata_stream;
 159
 160         /* for UST */
 161         int wait_fd;
 162         /* Node within channel thread ht */
 163         struct lttng_ht_node_u64 wait_fd_node;
 164
 165         /* Metadata cache is metadata channel */
 166         struct consumer_metadata_cache *metadata_cache;
 167         /* For UST metadata periodical flush */
 168         int switch_timer_enabled;
 169         timer_t switch_timer;
 170         int switch_timer_error;
 171
 172         /* For the live mode */
 173         int live_timer_enabled;
 174         timer_t live_timer;
 175         int live_timer_error;
 176         /* Channel is part of a live session ? */
 177         bool is_live;
 178
 179         /* On-disk circular buffer */
 180         uint64_t tracefile_size;
 181         uint64_t tracefile_count;
 182         /*
 183          * Monitor or not the streams of this channel meaning this indicates if the
 184          * streams should be sent to the data/metadata thread or added to the no
 185          * monitor list of the channel.
 186          */
 187         unsigned int monitor;
 188
 189         /*
 190          * Channel lock.
 191          *
 192          * This lock protects against concurrent update of channel.
 193          *
 194          * This is nested INSIDE the consumer data lock.
 195          * This is nested OUTSIDE the channel timer lock.
 196          * This is nested OUTSIDE the metadata cache lock.
 197          * This is nested OUTSIDE stream lock.
 198          * This is nested OUTSIDE consumer_relayd_sock_pair lock.
 199          */
 200         pthread_mutex_t lock;
 201
 202         /*
 203          * Channel teardown lock.
 204          *
 205          * This lock protect against teardown of channel. It is _never_
 206          * taken by the timer handler.
 207          *
 208          * This is nested INSIDE the consumer data lock.
 209          * This is nested INSIDE the channel lock.
 210          * This is nested OUTSIDE the metadata cache lock.
 211          * This is nested OUTSIDE stream lock.
 212          * This is nested OUTSIDE consumer_relayd_sock_pair lock.
 213          */
 214         pthread_mutex_t timer_lock;
 215
 216         /* Timer value in usec for live streaming. */
 217         unsigned int live_timer_interval;
 218
 219         int *stream_fds;
 220         int nr_stream_fds;
 221         char root_shm_path[PATH_MAX];
 222         char shm_path[PATH_MAX];
 223         /* Total number of discarded events for that channel. */
 224         uint64_t discarded_events;
 225         /* Total number of missed packets due to overwriting (overwrite). */
 226         uint64_t lost_packets;
 227
 228         bool streams_sent_to_relayd;
 229 };
 230
 231 struct stream_subbuffer {
 232         union {
 233                 /*
 234                  * CONSUMER_CHANNEL_SPLICE
 235                  * No ownership assumed.
 236                  */
 237                 int fd;
 238                 /* CONSUMER_CHANNEL_MMAP */
 239                 struct lttng_buffer_view buffer;
 240         } buffer;
 241         union {
 242                 /*
 243                  * Common members are fine to access through either
 244                  * union entries (as per C11, Common Initial Sequence).
 245                  */
 246                 struct {
 247                         unsigned long subbuf_size;
 248                         unsigned long padded_subbuf_size;
 249                         uint64_t version;
 250                         /*
 251                          * Left unset when unsupported.
 252                          *
 253                          * Indicates that this is the last sub-buffer of
 254                          * a series of sub-buffer that makes-up a coherent
 255                          * (parseable) unit of metadata.
 256                          */
 257                         LTTNG_OPTIONAL(bool) coherent;
 258                 } metadata;
 259                 struct {
 260                         unsigned long subbuf_size;
 261                         unsigned long padded_subbuf_size;
 262                         uint64_t packet_size;
 263                         uint64_t content_size;
 264                         uint64_t timestamp_begin;
 265                         uint64_t timestamp_end;
 266                         uint64_t events_discarded;
 267                         /* Left unset when unsupported. */
 268                         LTTNG_OPTIONAL(uint64_t) sequence_number;
 269                         uint64_t stream_id;
 270                         /* Left unset when unsupported. */
 271                         LTTNG_OPTIONAL(uint64_t) stream_instance_id;
 272                 } data;
 273         } info;
 274 };
 275
 276 /*
 277  * Perform any operation required to acknowledge
 278  * the wake-up of a consumer stream (e.g. consume a byte on a wake-up pipe).
 279  *
 280  * Stream and channel locks are acquired during this call.
 281  */
 282 typedef int (*on_wake_up_cb)(struct lttng_consumer_stream *);
 283
 284 /*
 285  * Perform any operation required before a consumer stream is put
 286  * to sleep before awaiting a data availability notification.
 287  *
 288  * Stream and channel locks are acquired during this call.
 289  */
 290 typedef int (*on_sleep_cb)(struct lttng_consumer_stream *,
 291                 struct lttng_consumer_local_data *);
 292
 293 /*
 294  * Acquire the subbuffer at the current 'consumed' position.
 295  *
 296  * Stream and channel locks are acquired during this call.
 297  */
 298 typedef int (*get_next_subbuffer_cb)(struct lttng_consumer_stream *,
 299                 struct stream_subbuffer *);
 300
 301 /*
 302  * Populate the stream_subbuffer's info member. The info to populate
 303  * depends on the type (metadata/data) of the stream.
 304  *
 305  * Stream and channel locks are acquired during this call.
 306  */
 307 typedef int (*extract_subbuffer_info_cb)(
 308                 struct lttng_consumer_stream *, struct stream_subbuffer *);
 309
 310 /*
 311  * Invoked after a subbuffer's info has been filled.
 312  *
 313  * Stream and channel locks are acquired during this call.
 314  */
 315 typedef int (*pre_consume_subbuffer_cb)(struct lttng_consumer_stream *,
 316                 const struct stream_subbuffer *);
 317
 318 /*
 319  * Consume subbuffer contents.
 320  *
 321  * Stream and channel locks are acquired during this call.
 322  */
 323 typedef ssize_t (*consume_subbuffer_cb)(struct lttng_consumer_local_data *,
 324                 struct lttng_consumer_stream *,
 325                 const struct stream_subbuffer *);
 326
 327 /*
 328  * Release the current subbuffer and advance the 'consumed' position by
 329  * one subbuffer.
 330  *
 331  * Stream and channel locks are acquired during this call.
 332  */
 333 typedef int (*put_next_subbuffer_cb)(struct lttng_consumer_stream *,
 334                 struct stream_subbuffer *);
 335
 336 /*
 337  * Invoked after consuming a subbuffer.
 338  *
 339  * Stream and channel locks are acquired during this call.
 340  */
 341 typedef int (*post_consume_cb)(struct lttng_consumer_stream *,
 342                 const struct stream_subbuffer *,
 343                 struct lttng_consumer_local_data *);
 344
 345 /*
 346  * Send a live beacon if no data is available.
 347  *
 348  * Stream and channel locks are acquired during this call.
 349  */
 350 typedef int (*send_live_beacon_cb)(struct lttng_consumer_stream *);
 351
 352 /*
 353  * Lock the stream and channel locks and any other stream-type specific
 354  * lock that need to be acquired during the processing of an
 355  * availability notification.
 356  */
 357 typedef void (*lock_cb)(struct lttng_consumer_stream *);
 358
 359 /*
 360  * Unlock the stream and channel locks and any other stream-type specific
 361  * lock before sleeping until the next availability notification.
 362  *
 363  * Stream and channel locks are acquired during this call.
 364  */
 365 typedef void (*unlock_cb)(struct lttng_consumer_stream *);
 366
 367 /*
 368  * Invoked when a subbuffer's metadata version does not match the last
 369  * known metadata version.
 370  *
 371  * Stream and channel locks are acquired during this call.
 372  */
 373 typedef void (*reset_metadata_cb)(struct lttng_consumer_stream *);
 374
 375 /*
 376  * Internal representation of the streams, sessiond_key is used to identify
 377  * uniquely a stream.
 378  */
 379 struct lttng_consumer_stream {
 380         /* HT node used by the data_ht and metadata_ht */
 381         struct lttng_ht_node_u64 node;
 382         /* stream indexed per channel key node */
 383         struct lttng_ht_node_u64 node_channel_id;
 384         /* HT node used in consumer_data.stream_list_ht */
 385         struct lttng_ht_node_u64 node_session_id;
 386         /* Pointer to associated channel. */
 387         struct lttng_consumer_channel *chan;
 388
 389         /* Key by which the stream is indexed for 'node'. */
 390         uint64_t key;
 391         /*
 392          * File descriptor of the data output file. This can be either a file or a
 393          * socket fd for relayd streaming.
 394          */
 395         int out_fd; /* output file to write the data */
 396         /* Write position in the output file descriptor */
 397         off_t out_fd_offset;
 398         /* Amount of bytes written to the output */
 399         uint64_t output_written;
 400         enum lttng_consumer_stream_state state;
 401         int shm_fd_is_copy;
 402         int data_read;
 403         int hangup_flush_done;
 404
 405         /*
 406          * Whether the stream is in a "complete" state (e.g. it does not have a
 407          * partially written sub-buffer.
 408          *
 409          * Initialized to "false" on stream creation (first packet is empty).
 410          *
 411          * The various transitions of the quiescent state are:
 412          *     - On "start" tracing: set to false, since the stream is not
 413          *       "complete".
 414          *     - On "stop" tracing: if !quiescent -> flush FINAL (update
 415          *       timestamp_end), and set to true; the stream has entered a
 416          *       complete/quiescent state.
 417          *     - On "destroy" or stream/application hang-up: if !quiescent ->
 418          *       flush FINAL, and set to true.
 419          *
 420          * NOTE: Update and read are protected by the stream lock.
 421          */
 422         bool quiescent;
 423
 424         /*
 425          * metadata_timer_lock protects flags waiting_on_metadata and
 426          * missed_metadata_flush.
 427          */
 428         pthread_mutex_t metadata_timer_lock;
 429         /*
 430          * Flag set when awaiting metadata to be pushed. Used in the
 431          * timer thread to skip waiting on the stream (and stream lock) to
 432          * ensure we can proceed to flushing metadata in live mode.
 433          */
 434         bool waiting_on_metadata;
 435         /* Raised when a timer misses a metadata flush. */
 436         bool missed_metadata_flush;
 437
 438         enum lttng_event_output output;
 439         /* Maximum subbuffer size. */
 440         unsigned long max_sb_size;
 441
 442         /*
 443          * Still used by the kernel for MMAP output. For UST, the ustctl getter is
 444          * used for the mmap base and offset.
 445          */
 446         void *mmap_base;
 447         unsigned long mmap_len;
 448
 449         /* For UST */
 450
 451         int wait_fd;
 452         /* UID/GID of the user owning the session to which stream belongs */
 453         uid_t uid;
 454         gid_t gid;
 455         /*
 456          * Relayd id, indicating on which relayd socket it goes. Set to -1ULL if
 457          * not the stream is not associated to a relay daemon.
 458          */
 459         uint64_t relayd_id;
 460         /*
 461          * Indicate if this stream was successfully sent to a relayd. This is set
 462          * after the refcount of the relayd is incremented and is checked when the
 463          * stream is closed before decrementing the refcount in order to avoid an
 464          * unbalanced state.
 465          */
 466         unsigned int sent_to_relayd;
 467
 468         /* Identify if the stream is the metadata */
 469         unsigned int metadata_flag;
 470         /*
 471          * Last known metadata version, reset the metadata file in case
 472          * of change.
 473          */
 474         uint64_t metadata_version;
 475         /* Used when the stream is set for network streaming */
 476         uint64_t relayd_stream_id;
 477         /*
 478          * When sending a stream packet to a relayd, this number is used to track
 479          * the packet sent by the consumer and seen by the relayd. When sending the
 480          * data header to the relayd, this number is sent and if the transmission
 481          * was successful, it is incremented.
 482          *
 483          * Even if the full data is not fully transmitted it won't matter since
 484          * only two possible error can happen after that where either the relayd
 485          * died or a read error is detected on the stream making this value useless
 486          * after that.
 487          *
 488          * This value SHOULD be read/updated atomically or with the lock acquired.
 489          */
 490         uint64_t next_net_seq_num;
 491         /*
 492          * Lock to use the stream FDs since they are used between threads.
 493          *
 494          * This is nested INSIDE the consumer_data lock.
 495          * This is nested INSIDE the channel lock.
 496          * This is nested INSIDE the channel timer lock.
 497          * This is nested OUTSIDE the metadata cache lock.
 498          * This is nested OUTSIDE consumer_relayd_sock_pair lock.
 499          */
 500         pthread_mutex_t lock;
 501         /* Tracing session id */
 502         uint64_t session_id;
 503         /*
 504          * Indicates if the stream end point is still active or not (network
 505          * streaming or local file system). The thread "owning" the stream is
 506          * handling this status and can be notified of a state change through the
 507          * consumer data appropriate pipe.
 508          */
 509         enum consumer_endpoint_status endpoint_status;
 510         /* Stream name. Format is: <channel_name>_<cpu_number> */
 511         char name[LTTNG_SYMBOL_NAME_LEN];
 512         /* Internal state of libustctl. */
 513         struct ustctl_consumer_stream *ustream;
 514         struct cds_list_head send_node;
 515         /* On-disk circular buffer */
 516         uint64_t tracefile_size_current;
 517         uint64_t tracefile_count_current;
 518         /*
 519          * Monitor or not the streams of this channel meaning this indicates if the
 520          * streams should be sent to the data/metadata thread or added to the no
 521          * monitor list of the channel.
 522          */
 523         unsigned int monitor;
 524         /*
 525          * Indicate if the stream is globally visible meaning that it has been
 526          * added to the multiple hash tables. If *not* set, NO lock should be
 527          * acquired in the destroy path.
 528          */
 529         unsigned int globally_visible;
 530         /*
 531          * Pipe to wake up the metadata poll thread when the UST metadata
 532          * cache is updated.
 533          */
 534         int ust_metadata_poll_pipe[2];
 535         /*
 536          * How much metadata was read from the metadata cache and sent
 537          * to the channel.
 538          */
 539         uint64_t ust_metadata_pushed;
 540         /*
 541          * Copy of the last discarded event value to detect the overflow of
 542          * the counter.
 543          */
 544         uint64_t last_discarded_events;
 545         /* Copy of the sequence number of the last packet extracted. */
 546         uint64_t last_sequence_number;
 547         /*
 548          * Index file object of the index file for this stream.
 549          */
 550         struct lttng_index_file *index_file;
 551
 552         /*
 553          * Local pipe to extract data when using splice.
 554          */
 555         int splice_pipe[2];
 556
 557         /*
 558          * Rendez-vous point between data and metadata stream in live mode.
 559          */
 560         pthread_cond_t metadata_rdv;
 561         pthread_mutex_t metadata_rdv_lock;
 562
 563         /* Indicate if the stream still has some data to be read. */
 564         unsigned int has_data:1;
 565         /*
 566          * Inform the consumer or relay to reset the metadata
 567          * file before writing in it (regeneration).
 568          */
 569         unsigned int reset_metadata_flag:1;
 570         struct {
 571                 /*
 572                  * Invoked in the order of declaration.
 573                  * See callback type definitions.
 574                  */
 575                 lock_cb lock;
 576                 on_wake_up_cb on_wake_up;
 577                 get_next_subbuffer_cb get_next_subbuffer;
 578                 extract_subbuffer_info_cb extract_subbuffer_info;
 579                 pre_consume_subbuffer_cb pre_consume_subbuffer;
 580                 reset_metadata_cb reset_metadata;
 581                 consume_subbuffer_cb consume_subbuffer;
 582                 put_next_subbuffer_cb put_next_subbuffer;
 583                 post_consume_cb post_consume;
 584                 send_live_beacon_cb send_live_beacon;
 585                 on_sleep_cb on_sleep;
 586                 unlock_cb unlock;
 587         } read_subbuffer_ops;
 588         struct metadata_bucket *metadata_bucket;
 589 };
 590
 591 /*
 592  * Internal representation of a relayd socket pair.
 593  */
 594 struct consumer_relayd_sock_pair {
 595         /* Network sequence number. */
 596         uint64_t id;
 597         /* Number of stream associated with this relayd */
 598         int refcount;
 599
 600         /*
 601          * This flag indicates whether or not we should destroy this object. The
 602          * destruction should ONLY occurs when this flag is set and the refcount is
 603          * set to zero.
 604          */
 605         unsigned int destroy_flag;
 606
 607         /*
 608          * Mutex protecting the control socket to avoid out of order packets
 609          * between threads sending data to the relayd. Since metadata data is sent
 610          * over that socket, at least two sendmsg() are needed (header + data)
 611          * creating a race for packets to overlap between threads using it.
 612          *
 613          * This is nested INSIDE the consumer_data lock.
 614          * This is nested INSIDE the stream lock.
 615          */
 616         pthread_mutex_t ctrl_sock_mutex;
 617
 618         /* Control socket. Command and metadata are passed over it */
 619         struct lttcomm_relayd_sock control_sock;
 620
 621         /*
 622          * We don't need a mutex at this point since we only splice or write single
 623          * large chunk of data with a header appended at the begining. Moreover,
 624          * this socket is for now only used in a single thread.
 625          */
 626         struct lttcomm_relayd_sock data_sock;
 627         struct lttng_ht_node_u64 node;
 628
 629         /* Session id on both sides for the sockets. */
 630         uint64_t relayd_session_id;
 631         uint64_t sessiond_session_id;
 632         struct lttng_consumer_local_data *ctx;
 633 };
 634
 635 /*
 636  * UST consumer local data to the program. One or more instance per
 637  * process.
 638  */
 639 struct lttng_consumer_local_data {
 640         /*
 641          * Function to call when data is available on a buffer.
 642          * Returns the number of bytes read, or negative error value.
 643          */
 644         ssize_t (*on_buffer_ready)(struct lttng_consumer_stream *stream,
 645                         struct lttng_consumer_local_data *ctx,
 646                         bool locked_by_caller);
 647         /*
 648          * function to call when we receive a new channel, it receives a
 649          * newly allocated channel, depending on the return code of this
 650          * function, the new channel will be handled by the application
 651          * or the library.
 652          *
 653          * Returns:
 654          *    > 0 (success, FD is kept by application)
 655          *   == 0 (success, FD is left to library)
 656          *    < 0 (error)
 657          */
 658         int (*on_recv_channel)(struct lttng_consumer_channel *channel);
 659         /*
 660          * function to call when we receive a new stream, it receives a
 661          * newly allocated stream, depending on the return code of this
 662          * function, the new stream will be handled by the application
 663          * or the library.
 664          *
 665          * Returns:
 666          *    > 0 (success, FD is kept by application)
 667          *   == 0 (success, FD is left to library)
 668          *    < 0 (error)
 669          */
 670         int (*on_recv_stream)(struct lttng_consumer_stream *stream);
 671         /*
 672          * function to call when a stream is getting updated by the session
 673          * daemon, this function receives the sessiond key and the new
 674          * state, depending on the return code of this function the
 675          * update of state for the stream is handled by the application
 676          * or the library.
 677          *
 678          * Returns:
 679          *    > 0 (success, FD is kept by application)
 680          *   == 0 (success, FD is left to library)
 681          *    < 0 (error)
 682          */
 683         int (*on_update_stream)(uint64_t sessiond_key, uint32_t state);
 684         enum lttng_consumer_type type;
 685         /* socket to communicate errors with sessiond */
 686         int consumer_error_socket;
 687         /* socket to ask metadata to sessiond. */
 688         int consumer_metadata_socket;
 689         /*
 690          * Protect consumer_metadata_socket.
 691          *
 692          * This is nested OUTSIDE the metadata cache lock.
 693          */
 694         pthread_mutex_t metadata_socket_lock;
 695         /* socket to exchange commands with sessiond */
 696         char *consumer_command_sock_path;
 697         /* communication with splice */
 698         int consumer_channel_pipe[2];
 699         /* Data stream poll thread pipe. To transfer data stream to the thread */
 700         struct lttng_pipe *consumer_data_pipe;
 701
 702         /*
 703          * Data thread use that pipe to catch wakeup from read subbuffer that
 704          * detects that there is still data to be read for the stream encountered.
 705          * Before doing so, the stream is flagged to indicate that there is still
 706          * data to be read.
 707          *
 708          * Both pipes (read/write) are owned and used inside the data thread.
 709          */
 710         struct lttng_pipe *consumer_wakeup_pipe;
 711         /* Indicate if the wakeup thread has been notified. */
 712         unsigned int has_wakeup:1;
 713
 714         /* to let the signal handler wake up the fd receiver thread */
 715         int consumer_should_quit[2];
 716         /* Metadata poll thread pipe. Transfer metadata stream to it */
 717         struct lttng_pipe *consumer_metadata_pipe;
 718 };
 719
 720 /*
 721  * Library-level data. One instance per process.
 722  */
 723 struct lttng_consumer_global_data {
 724         /*
 725          * At this time, this lock is used to ensure coherence between the count
 726          * and number of element in the hash table. It's also a protection for
 727          * concurrent read/write between threads.
 728          *
 729          * This is nested OUTSIDE the stream lock.
 730          * This is nested OUTSIDE the consumer_relayd_sock_pair lock.
 731          */
 732         pthread_mutex_t lock;
 733
 734         /*
 735          * Number of streams in the data stream hash table declared outside.
 736          * Protected by consumer_data.lock.
 737          */
 738         int stream_count;
 739
 740         /* Channel hash table protected by consumer_data.lock. */
 741         struct lttng_ht *channel_ht;
 742         /*
 743          * Flag specifying if the local array of FDs needs update in the
 744          * poll function. Protected by consumer_data.lock.
 745          */
 746         unsigned int need_update;
 747         enum lttng_consumer_type type;
 748
 749         /*
 750          * Relayd socket(s) hashtable indexed by network sequence number. Each
 751          * stream has an index which associate the right relayd socket to use.
 752          */
 753         struct lttng_ht *relayd_ht;
 754
 755         /*
 756          * This hash table contains all streams (metadata and data) indexed by
 757          * session id. In other words, the ht is indexed by session id and each
 758          * bucket contains the list of associated streams.
 759          *
 760          * This HT uses the "node_session_id" of the consumer stream.
 761          */
 762         struct lttng_ht *stream_list_ht;
 763
 764         /*
 765          * This HT uses the "node_channel_id" of the consumer stream.
 766          */
 767         struct lttng_ht *stream_per_chan_id_ht;
 768 };
 769
 770 /*
 771  * Set to nonzero when the consumer is exiting. Updated by signal
 772  * handler and thread exit, read by threads.
 773  */
 774 extern volatile int consumer_quit;
 775
 776 /*
 777  * Init consumer data structures.
 778  */
 779 int lttng_consumer_init(void);
 780
 781 /*
 782  * Set the error socket for communication with a session daemon.
 783  */
 784 void lttng_consumer_set_error_sock(struct lttng_consumer_local_data *ctx,
 785                 int sock);
 786
 787 /*
 788  * Set the command socket path for communication with a session daemon.
 789  */
 790 void lttng_consumer_set_command_sock_path(
 791                 struct lttng_consumer_local_data *ctx, char *sock);
 792
 793 /*
 794  * Send return code to session daemon.
 795  *
 796  * Returns the return code of sendmsg : the number of bytes transmitted or -1
 797  * on error.
 798  */
 799 int lttng_consumer_send_error(struct lttng_consumer_local_data *ctx, int cmd);
 800
 801 /*
 802  * Called from signal handler to ensure a clean exit.
 803  */
 804 void lttng_consumer_should_exit(struct lttng_consumer_local_data *ctx);
 805
 806 /*
 807  * Cleanup the daemon's socket on exit.
 808  */
 809 void lttng_consumer_cleanup(void);
 810
 811 /*
 812  * Poll on the should_quit pipe and the command socket return -1 on error and
 813  * should exit, 0 if data is available on the command socket
 814  */
 815 int lttng_consumer_poll_socket(struct pollfd *kconsumer_sockpoll);
 816
 817 struct lttng_consumer_stream *consumer_allocate_stream(
 818                 struct lttng_consumer_channel *channel,
 819                 uint64_t channel_key,
 820                 uint64_t stream_key,
 821                 enum lttng_consumer_stream_state state,
 822                 const char *channel_name,
 823                 uid_t uid,
 824                 gid_t gid,
 825                 uint64_t relayd_id,
 826                 uint64_t session_id,
 827                 int cpu,
 828                 int *alloc_ret,
 829                 enum consumer_channel_type type,
 830                 unsigned int monitor);
 831 struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
 832                 uint64_t session_id,
 833                 const char *pathname,
 834                 const char *name,
 835                 uid_t uid,
 836                 gid_t gid,
 837                 uint64_t relayd_id,
 838                 enum lttng_event_output output,
 839                 uint64_t tracefile_size,
 840                 uint64_t tracefile_count,
 841                 uint64_t session_id_per_pid,
 842                 unsigned int monitor,
 843                 unsigned int live_timer_interval,
 844                 bool is_in_live_session,
 845                 const char *root_shm_path,
 846                 const char *shm_path);
 847 void consumer_del_stream(struct lttng_consumer_stream *stream,
 848                 struct lttng_ht *ht);
 849 void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
 850                 struct lttng_ht *ht);
 851 int consumer_add_channel(struct lttng_consumer_channel *channel,
 852                 struct lttng_consumer_local_data *ctx);
 853 void consumer_del_channel(struct lttng_consumer_channel *channel);
 854
 855 /* lttng-relayd consumer command */
 856 struct consumer_relayd_sock_pair *consumer_find_relayd(uint64_t key);
 857 int consumer_send_relayd_stream(struct lttng_consumer_stream *stream, char *path);
 858 int consumer_send_relayd_streams_sent(uint64_t relayd_id);
 859 void close_relayd_stream(struct lttng_consumer_stream *stream);
 860 struct lttng_consumer_channel *consumer_find_channel(uint64_t key);
 861 int consumer_handle_stream_before_relayd(struct lttng_consumer_stream *stream,
 862                 size_t data_size);
 863 void consumer_steal_stream_key(int key, struct lttng_ht *ht);
 864
 865 struct lttng_consumer_local_data *lttng_consumer_create(
 866                 enum lttng_consumer_type type,
 867                 ssize_t (*buffer_ready)(struct lttng_consumer_stream *stream,
 868                         struct lttng_consumer_local_data *ctx,
 869                         bool locked_by_caller),
 870                 int (*recv_channel)(struct lttng_consumer_channel *channel),
 871                 int (*recv_stream)(struct lttng_consumer_stream *stream),
 872                 int (*update_stream)(uint64_t sessiond_key, uint32_t state));
 873 void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx);
 874 ssize_t lttng_consumer_on_read_subbuffer_mmap(
 875                 struct lttng_consumer_stream *stream,
 876                 const struct lttng_buffer_view *buffer,
 877                 unsigned long padding);
 878 ssize_t lttng_consumer_on_read_subbuffer_splice(
 879                 struct lttng_consumer_local_data *ctx,
 880                 struct lttng_consumer_stream *stream, unsigned long len,
 881                 unsigned long padding);
 882 int lttng_consumer_take_snapshot(struct lttng_consumer_stream *stream);
 883 int lttng_consumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
 884                 unsigned long *pos);
 885 int lttng_ustconsumer_get_wakeup_fd(struct lttng_consumer_stream *stream);
 886 int lttng_ustconsumer_close_wakeup_fd(struct lttng_consumer_stream *stream);
 887 void *consumer_thread_metadata_poll(void *data);
 888 void *consumer_thread_data_poll(void *data);
 889 void *consumer_thread_sessiond_poll(void *data);
 890 void *consumer_thread_channel_poll(void *data);
 891 int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 892                 int sock, struct pollfd *consumer_sockpoll);
 893
 894 ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
 895                 struct lttng_consumer_local_data *ctx,
 896                 bool locked_by_caller);
 897 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream);
 898 void consumer_add_relayd_socket(uint64_t relayd_id, int sock_type,
 899                 struct lttng_consumer_local_data *ctx, int sock,
 900                 struct pollfd *consumer_sockpoll, struct lttcomm_relayd_sock *relayd_sock,
 901                 uint64_t sessiond_id, uint64_t relayd_session_id);
 902 void consumer_flag_relayd_for_destroy(
 903                 struct consumer_relayd_sock_pair *relayd);
 904 int consumer_data_pending(uint64_t id);
 905 int consumer_send_status_msg(int sock, int ret_code);
 906 int consumer_send_status_channel(int sock,
 907                 struct lttng_consumer_channel *channel);
 908 void notify_thread_del_channel(struct lttng_consumer_local_data *ctx,
 909                 uint64_t key);
 910 void consumer_destroy_relayd(struct consumer_relayd_sock_pair *relayd);
 911 unsigned long consumer_get_consume_start_pos(unsigned long consumed_pos,
 912                 unsigned long produced_pos, uint64_t nb_packets_per_stream,
 913                 uint64_t max_sb_size);
 914 int consumer_add_data_stream(struct lttng_consumer_stream *stream);
 915 void consumer_del_stream_for_data(struct lttng_consumer_stream *stream);
 916 int consumer_add_metadata_stream(struct lttng_consumer_stream *stream);
 917 void consumer_del_stream_for_metadata(struct lttng_consumer_stream *stream);
 918 int consumer_create_index_file(struct lttng_consumer_stream *stream);
 919 void lttng_consumer_cleanup_relayd(struct consumer_relayd_sock_pair *relayd);
 920
 921 #endif /* LIB_CONSUMER_H */