1 #ifndef _VIEWER_SESSION_H
2 #define _VIEWER_SESSION_H
5 * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
6 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
7 * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 * SPDX-License-Identifier: GPL-2.0-only
16 #include <urcu/list.h>
19 #include <common/hashtable/hashtable.h>
20 #include <common/trace-chunk.h>
24 struct relay_viewer_session
{
26 * Session list. Updates are protected by the session_list_lock.
27 * Traversals are protected by RCU.
28 * This list limits the design to having the sessions in at most
31 struct cds_list_head session_list
; /* RCU list. */
32 pthread_mutex_t session_list_lock
; /* Protects list updates. */
34 * The viewer session's current trace chunk is initially set, when
35 * a viewer attaches to the viewer session, to a copy the corresponding
36 * relay_session's current trace chunk.
38 * A live session always attempts to "catch-up" to the newest available
39 * trace chunk. This means that when a viewer reaches the end of a
40 * trace chunk, the viewer session may not transition to the "next" one:
41 * it jumps to the most recent trace chunk available (the one being
42 * produced by the relay_session). Hence, if the producer performs
43 * multiple rotations before a viewer completes the consumption of a
44 * trace chunk, it will skip over those "intermediary" trace chunks.
46 * A viewer session updates its current trace chunk when:
47 * 1) new viewer streams are created,
48 * 2) a new index is requested,
49 * 3) metadata is requested.
51 * Hence, as a general principle, the viewer session will reference the
52 * most recent trace chunk available _even if its streams do not point to
53 * it_. It indicates which trace chunk viewer streams should transition
54 * to when the end of their current trace chunk is reached.
56 struct lttng_trace_chunk
*current_trace_chunk
;
59 struct relay_viewer_session
*viewer_session_create(void);
60 void viewer_session_destroy(struct relay_viewer_session
*vsession
);
61 void viewer_session_close(struct relay_viewer_session
*vsession
);
63 enum lttng_viewer_attach_return_code
viewer_session_attach(
64 struct relay_viewer_session
*vsession
,
65 struct relay_session
*session
);
66 int viewer_session_is_attached(struct relay_viewer_session
*vsession
,
67 struct relay_session
*session
);
68 void viewer_session_close_one_session(struct relay_viewer_session
*vsession
,
69 struct relay_session
*session
);
70 int viewer_session_set_trace_chunk_copy(struct relay_viewer_session
*vsession
,
71 struct lttng_trace_chunk
*relay_session_trace_chunk
);
73 #endif /* _VIEWER_SESSION_H */