src/bin/lttng-relayd/stream.h

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License, version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 51
  16  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #ifndef _STREAM_H
  20 #define _STREAM_H
  21
  22 #include <limits.h>
  23 #include <inttypes.h>
  24 #include <pthread.h>
  25 #include <urcu/list.h>
  26
  27 #include <common/hashtable/hashtable.h>
  28
  29 #include "session.h"
  30
  31 /*
  32  * Represents a stream in the relay
  33  */
  34 struct relay_stream {
  35         uint64_t stream_handle;
  36         uint64_t prev_seq;      /* previous data sequence number encountered */
  37         struct lttng_ht_node_u64 node;
  38         /*
  39          * When we receive a stream, it gets stored in a list (on a per connection
  40          * basis) until we have all the streams of the same channel and the metadata
  41          * associated with it, then it gets flagged with viewer_ready.
  42          */
  43         struct cds_list_head recv_list;
  44
  45         /* Added to the corresponding ctf_trace. */
  46         struct cds_list_head trace_list;
  47         struct rcu_head rcu_node;
  48         uint64_t session_id;
  49         int fd;
  50         /* FD on which to write the index data. */
  51         int index_fd;
  52         /* FD on which to read the index data for the viewer. */
  53         int read_index_fd;
  54
  55         char *path_name;
  56         char *channel_name;
  57         /* on-disk circular buffer of tracefiles */
  58         uint64_t tracefile_size;
  59         uint64_t tracefile_size_current;
  60         uint64_t tracefile_count;
  61         uint64_t tracefile_count_current;
  62         /* To inform the viewer up to where it can go back in time. */
  63         uint64_t oldest_tracefile_id;
  64
  65         uint64_t total_index_received;
  66         uint64_t last_net_seq_num;
  67
  68         /*
  69          * To protect from concurrent read/update. Also used to synchronize the
  70          * closing of this stream.
  71          */
  72         pthread_mutex_t lock;
  73
  74         /*
  75          * If the stream is inactive, this field is updated with the live beacon
  76          * timestamp end, when it is active, this field == -1ULL.
  77          */
  78         uint64_t beacon_ts_end;
  79         /*
  80          * Number of indexes that are supposed to be complete soon.
  81          * Avoid sending the inactivity beacon to the client when data is in
  82          * transit.
  83          */
  84         int indexes_in_flight;
  85         /*
  86          * CTF stream ID, -1ULL when unset.
  87          */
  88         uint64_t ctf_stream_id;
  89         /*
  90          * To protect the update of the close_write_flag and the checks of
  91          * the tracefile_count_current.
  92          * It is taken before checking whenever we need to know if the
  93          * writer and reader are working in the same tracefile.
  94          */
  95         pthread_mutex_t viewer_stream_rotation_lock;
  96
  97         /* Information telling us when to close the stream  */
  98         unsigned int close_flag:1;
  99         /*
 100          * Indicates if the stream has been effectively closed thus having the
 101          * information in it invalidated but NOT freed. The stream lock MUST be
 102          * held to read/update that value.
 103          */
 104         unsigned int terminated_flag:1;
 105         /* Indicate if the stream was initialized for a data pending command. */
 106         unsigned int data_pending_check_done:1;
 107         unsigned int metadata_flag:1;
 108         /*
 109          * To detect when we start overwriting old data, it is used to
 110          * update the oldest_tracefile_id.
 111          */
 112         unsigned int tracefile_overwrite:1;
 113         /*
 114          * Can this stream be used by a viewer or are we waiting for additional
 115          * information.
 116          */
 117         unsigned int viewer_ready:1;
 118 };
 119
 120 struct relay_stream *stream_find_by_id(struct lttng_ht *ht,
 121                 uint64_t stream_id);
 122 int stream_close(struct relay_session *session, struct relay_stream *stream);
 123 void stream_delete(struct lttng_ht *ht, struct relay_stream *stream);
 124 void stream_destroy(struct relay_stream *stream);
 125
 126 #endif /* _STREAM_H */