src/bin/lttng-relayd/lttng-relayd.h

   1 /*
   2  * Copyright (C) 2012 - 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
   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, 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
  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 #ifndef LTTNG_RELAYD_H
  20 #define LTTNG_RELAYD_H
  21
  22 #define _LGPL_SOURCE
  23 #include <limits.h>
  24 #include <urcu.h>
  25 #include <urcu/wfqueue.h>
  26 #include <urcu/list.h>
  27
  28 #include <common/hashtable/hashtable.h>
  29 #include <common/index/ctf-index.h>
  30
  31 #include "ctf-trace.h"
  32
  33 /*
  34  * Queue used to enqueue relay requests
  35  */
  36 struct relay_cmd_queue {
  37         struct cds_wfq_queue queue;
  38         int32_t futex;
  39 };
  40
  41 enum connection_type {
  42         RELAY_DATA                  = 1,
  43         RELAY_CONTROL               = 2,
  44         RELAY_VIEWER_COMMAND        = 3,
  45         RELAY_VIEWER_NOTIFICATION   = 4,
  46 };
  47
  48 /*
  49  * When we receive a stream, it gets stored in a list (on a per connection
  50  * basis) until we have all the streams of the same channel and the metadata
  51  * associated with it, then it gets flagged with viewer_ready.
  52  */
  53 struct relay_stream_recv_handle {
  54         uint64_t id;    /* stream handle */
  55         struct cds_list_head node;
  56 };
  57
  58 /*
  59  * Represents a session for the relay point of view
  60  */
  61 struct relay_session {
  62         /*
  63          * This session id is used to identify a set of stream to a tracing session
  64          * but also make sure we have a unique session id associated with a session
  65          * daemon which can provide multiple data source.
  66          */
  67         uint64_t id;
  68         struct lttcomm_sock *sock;
  69         char session_name[NAME_MAX];
  70         char hostname[HOST_NAME_MAX];
  71         uint32_t live_timer;
  72         struct lttng_ht_node_ulong session_n;
  73         struct rcu_head rcu_node;
  74         uint32_t viewer_attached;
  75         uint32_t stream_count;
  76         /* Tell if this session is for a snapshot or not. */
  77         unsigned int snapshot:1;
  78
  79         /*
  80          * Indicate version protocol for this session. This is especially useful
  81          * for the data thread that has no idea which version it operates on since
  82          * linking control/data sockets is non trivial.
  83          */
  84         uint64_t minor;
  85         uint64_t major;
  86         /*
  87          * Flag checked and exchanged with uatomic_cmpxchg to tell the
  88          * viewer-side if new streams got added since the last check.
  89          */
  90         unsigned long new_streams;
  91 };
  92
  93 /*
  94  * Represents a stream in the relay
  95  */
  96 struct relay_stream {
  97         uint64_t stream_handle;
  98         uint64_t prev_seq;      /* previous data sequence number encountered */
  99         struct lttng_ht_node_ulong stream_n;
 100         struct relay_session *session;
 101         struct rcu_head rcu_node;
 102         int fd;
 103         /* FD on which to write the index data. */
 104         int index_fd;
 105         /* FD on which to read the index data for the viewer. */
 106         int read_index_fd;
 107
 108         char *path_name;
 109         char *channel_name;
 110         /* on-disk circular buffer of tracefiles */
 111         uint64_t tracefile_size;
 112         uint64_t tracefile_size_current;
 113         uint64_t tracefile_count;
 114         uint64_t tracefile_count_current;
 115         /* To inform the viewer up to where it can go back in time. */
 116         uint64_t oldest_tracefile_id;
 117
 118         uint64_t total_index_received;
 119         struct relay_viewer_stream *viewer_stream;
 120         uint64_t last_net_seq_num;
 121
 122         /*
 123          * This node is added to the *control* connection hash table and the
 124          * pointer is copied in here so we can access it when deleting this object.
 125          * When deleting this, the ctf trace ht MUST NOT be destroyed. This happens
 126          * at connection deletion.
 127          */
 128         struct lttng_ht_node_str ctf_trace_node;
 129         struct lttng_ht *ctf_traces_ht;
 130
 131         /*
 132          * To protect from concurrent read/update between the
 133          * streaming-side and the viewer-side.
 134          * This lock must be held, we reading/updating the
 135          * ctf_trace pointer.
 136          */
 137         pthread_mutex_t lock;
 138
 139         struct ctf_trace *ctf_trace;
 140         /*
 141          * If the stream is inactive, this field is updated with the live beacon
 142          * timestamp end, when it is active, this field == -1ULL.
 143          */
 144         uint64_t beacon_ts_end;
 145         /*
 146          * To protect the update of the close_write_flag and the checks of
 147          * the tracefile_count_current.
 148          * It is taken before checking whenever we need to know if the
 149          * writer and reader are working in the same tracefile.
 150          */
 151         pthread_mutex_t viewer_stream_rotation_lock;
 152
 153         /* Information telling us when to close the stream  */
 154         unsigned int close_flag:1;
 155         /* Indicate if the stream was initialized for a data pending command. */
 156         unsigned int data_pending_check_done:1;
 157         unsigned int metadata_flag:1;
 158         /*
 159          * To detect when we start overwriting old data, it is used to
 160          * update the oldest_tracefile_id.
 161          */
 162         unsigned int tracefile_overwrite:1;
 163         /*
 164          * Can this stream be used by a viewer or are we waiting for additional
 165          * information.
 166          */
 167         unsigned int viewer_ready:1;
 168 };
 169
 170 /*
 171  * Shadow copy of the relay_stream structure for the viewer side.  The only
 172  * fields updated by the writer (streaming side) after allocation are :
 173  * total_index_received and close_flag. Everything else is updated by the
 174  * reader (viewer side).
 175  */
 176 struct relay_viewer_stream {
 177         uint64_t stream_handle;
 178         uint64_t session_id;
 179         int read_fd;
 180         int index_read_fd;
 181         char *path_name;
 182         char *channel_name;
 183         uint64_t last_sent_index;
 184         uint64_t total_index_received;
 185         uint64_t tracefile_count;
 186         uint64_t tracefile_count_current;
 187         /* Stop after reading this tracefile. */
 188         uint64_t tracefile_count_last;
 189         struct lttng_ht_node_u64 stream_n;
 190         struct rcu_head rcu_node;
 191         struct ctf_trace *ctf_trace;
 192         /*
 193          * This lock blocks only when the writer is about to start overwriting
 194          * a file currently read by the reader.
 195          *
 196          * This is nested INSIDE the viewer_stream_rotation_lock.
 197          */
 198         pthread_mutex_t overwrite_lock;
 199         /* Information telling us if the stream is a metadata stream. */
 200         unsigned int metadata_flag:1;
 201         /*
 202          * Information telling us that the stream is closed in write, so
 203          * we don't expect new indexes and we can read up to EOF.
 204          */
 205         unsigned int close_write_flag:1;
 206         /*
 207          * If the streaming side closes a FD in use in the viewer side,
 208          * it sets this flag to inform that it is a normal error.
 209          */
 210         unsigned int abort_flag:1;
 211 };
 212
 213 /*
 214  * Internal structure to map a socket with the corresponding session.
 215  * A hashtable indexed on the socket FD is used for the lookups.
 216  */
 217 struct relay_command {
 218         struct lttcomm_sock *sock;
 219         struct relay_session *session;
 220         struct cds_wfq_node node;
 221         struct lttng_ht_node_ulong sock_n;
 222         struct rcu_head rcu_node;
 223         enum connection_type type;
 224         /* protocol version to use for this session */
 225         uint32_t major;
 226         uint32_t minor;
 227         struct lttng_ht *ctf_traces_ht; /* indexed by path name */
 228         uint64_t session_id;
 229         struct cds_list_head recv_head;
 230         unsigned int version_check_done:1;
 231 };
 232
 233 struct relay_local_data {
 234         struct lttng_ht *sessions_ht;
 235 };
 236
 237 extern char *opt_output_path;
 238
 239 extern struct lttng_ht *relay_streams_ht;
 240 extern struct lttng_ht *viewer_streams_ht;
 241 extern struct lttng_ht *indexes_ht;
 242
 243 extern const char *tracing_group_name;
 244
 245 extern const char * const config_section_name;
 246
 247 extern int thread_quit_pipe[2];
 248
 249 struct relay_stream *relay_stream_find_by_id(uint64_t stream_id);
 250 void lttng_relay_notify_ready(void);
 251
 252 #endif /* LTTNG_RELAYD_H */