src/bin/lttng-relayd/stream.h

   1 #ifndef _STREAM_H
   2 #define _STREAM_H
   3
   4 /*
   5  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   6  *                      David Goulet <dgoulet@efficios.com>
   7  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License, version 2 only, as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  16  * more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along with
  19  * this program; if not, write to the Free Software Foundation, Inc., 51
  20  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include <limits.h>
  24 #include <inttypes.h>
  25 #include <pthread.h>
  26 #include <urcu/list.h>
  27
  28 #include <common/hashtable/hashtable.h>
  29 #include <common/trace-chunk.h>
  30
  31 #include "session.h"
  32 #include "stream-fd.h"
  33 #include "tracefile-array.h"
  34
  35 /*
  36  * Represents a stream in the relay
  37  */
  38 struct relay_stream {
  39         uint64_t stream_handle;
  40
  41         struct urcu_ref ref;
  42         /* Back reference to trace. Protected by refcount on trace object. */
  43         struct ctf_trace *trace;
  44
  45         /*
  46          * To protect from concurrent read/update. The viewer stream
  47          * lock nests inside the stream lock. The stream lock nests
  48          * inside the ctf_trace lock.
  49          */
  50         pthread_mutex_t lock;
  51         /* previous data sequence number written to disk. */
  52         uint64_t prev_data_seq;
  53         /* previous index sequence number written to disk. */
  54         uint64_t prev_index_seq;
  55         /* seq num to encounter before closing. */
  56         uint64_t last_net_seq_num;
  57
  58         /* FD on which to write the stream data. */
  59         struct stream_fd *stream_fd;
  60         /* index file on which to write the index data. */
  61         struct lttng_index_file *index_file;
  62
  63         char *path_name;
  64         /*
  65          * prev_path_name is only used for session rotation support.
  66          * It is essentially used to work around the fact that index
  67          * files are always created from the 'data' connection.
  68          *
  69          * Hence, it is possible to receive a ROTATE_STREAM command
  70          * which affects the stream's path_name before the creation of
  71          * an index file. In this situation, the index file of the
  72          * 'previous' chunk would be created in the new destination folder.
  73          *
  74          * It would then be unlinked when the actual index of the new chunk
  75          * is created.
  76          */
  77         char *prev_path_name;
  78         char *channel_name;
  79
  80         /* On-disk circular buffer of tracefiles. */
  81         uint64_t tracefile_size;
  82         uint64_t tracefile_size_current;
  83         uint64_t tracefile_count;
  84
  85         /*
  86          * Position in the tracefile where we have the full index also on disk.
  87          */
  88         uint64_t pos_after_last_complete_data_index;
  89
  90         /*
  91          * Counts the number of received indexes. The "tag" associated
  92          * with an index is taken before incrementing this seqcount.
  93          * Therefore, the sequence tag associated with the last index
  94          * received is always index_received_seqcount - 1.
  95          */
  96         uint64_t index_received_seqcount;
  97
  98         /*
  99          * Tracefile array is an index of the stream trace files,
 100          * indexed by position. It allows keeping track of the oldest
 101          * available indexes when overwriting trace files in tracefile
 102          * rotation.
 103          */
 104         struct tracefile_array *tfa;
 105
 106         bool closed;            /* Stream is closed. */
 107         bool close_requested;   /* Close command has been received. */
 108
 109         /*
 110          * Counts number of indexes in indexes_ht. Redundant info.
 111          * Protected by stream lock.
 112          */
 113         int indexes_in_flight;
 114         struct lttng_ht *indexes_ht;
 115
 116         /*
 117          * If the stream is inactive, this field is updated with the
 118          * live beacon timestamp end, when it is active, this
 119          * field == -1ULL.
 120          */
 121         uint64_t beacon_ts_end;
 122
 123         /* CTF stream ID, -1ULL when unset (first packet not received yet). */
 124         uint64_t ctf_stream_id;
 125
 126         /* Indicate if the stream was initialized for a data pending command. */
 127         bool data_pending_check_done;
 128
 129         /* Is this stream a metadata stream ? */
 130         bool is_metadata;
 131         /* Amount of metadata received (bytes). */
 132         uint64_t metadata_received;
 133
 134         /*
 135          * Member of the stream list in struct ctf_trace.
 136          * Updates are protected by the stream_list_lock.
 137          * Traversals are protected by RCU.
 138          */
 139         struct cds_list_head stream_node;
 140         /*
 141          * Temporary list belonging to the connection until all streams
 142          * are received for that connection.
 143          * Member of the stream recv list in the connection.
 144          * Updates are protected by the stream_recv_list_lock.
 145          * Traversals are protected by RCU.
 146          */
 147         bool in_recv_list;
 148         struct cds_list_head recv_node;
 149         bool published; /* Protected by session lock. */
 150         /*
 151          * Node of stream within global stream hash table.
 152          */
 153         struct lttng_ht_node_u64 node;
 154         bool in_stream_ht;              /* is stream in stream hash table. */
 155         struct rcu_head rcu_node;       /* For call_rcu teardown. */
 156         /*
 157          * When we have written the data and index corresponding to this
 158          * seq_num, rotate the tracefile (session rotation). The path_name is
 159          * already up-to-date.
 160          * This is set to -1ULL when no rotation is pending.
 161          *
 162          * Always access with stream lock held.
 163          */
 164         uint64_t rotate_at_seq_num;
 165         /*
 166          * When rotate_at_seq_num != -1ULL, meaning that a rotation is ongoing,
 167          * data_rotated and index_rotated respectively indicate if the stream's
 168          * data and index have been rotated. A rotation is considered completed
 169          * when both rotations have occurred.
 170          */
 171         bool data_rotated;
 172         bool index_rotated;
 173         /*
 174          * `trace_chunk` is the trace chunk to which the file currently
 175          * being produced (if any) belongs.
 176          */
 177         struct lttng_trace_chunk *trace_chunk;
 178 };
 179
 180 struct relay_stream *stream_create(struct ctf_trace *trace,
 181         uint64_t stream_handle, char *path_name,
 182         char *channel_name, uint64_t tracefile_size,
 183         uint64_t tracefile_count);
 184
 185 struct relay_stream *stream_get_by_id(uint64_t stream_id);
 186 bool stream_get(struct relay_stream *stream);
 187 void stream_put(struct relay_stream *stream);
 188 void try_stream_close(struct relay_stream *stream);
 189 void stream_publish(struct relay_stream *stream);
 190 void print_relay_streams(void);
 191
 192 #endif /* _STREAM_H */