| 1 | #ifndef _VIEWER_SESSION_H |
| 2 | #define _VIEWER_SESSION_H |
| 3 | |
| 4 | /* |
| 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> |
| 8 | * |
| 9 | * SPDX-License-Identifier: GPL-2.0-only |
| 10 | * |
| 11 | */ |
| 12 | |
| 13 | #include <limits.h> |
| 14 | #include <inttypes.h> |
| 15 | #include <pthread.h> |
| 16 | #include <urcu/list.h> |
| 17 | #include <urcu/ref.h> |
| 18 | |
| 19 | #include <common/hashtable/hashtable.h> |
| 20 | #include <common/trace-chunk.h> |
| 21 | |
| 22 | #include "session.h" |
| 23 | #include "lttng-viewer-abi.h" |
| 24 | |
| 25 | struct relay_viewer_session { |
| 26 | /* |
| 27 | * Session list. Updates are protected by the session_list_lock. |
| 28 | * Traversals are protected by RCU. |
| 29 | * This list limits the design to having the sessions in at most |
| 30 | * one viewer session. |
| 31 | */ |
| 32 | struct cds_list_head session_list; /* RCU list. */ |
| 33 | pthread_mutex_t session_list_lock; /* Protects list updates. */ |
| 34 | /* |
| 35 | * The viewer session's current trace chunk is initially set, when |
| 36 | * a viewer attaches to the viewer session, to a copy the corresponding |
| 37 | * relay_session's current trace chunk. |
| 38 | * |
| 39 | * A live session always attempts to "catch-up" to the newest available |
| 40 | * trace chunk. This means that when a viewer reaches the end of a |
| 41 | * trace chunk, the viewer session may not transition to the "next" one: |
| 42 | * it jumps to the most recent trace chunk available (the one being |
| 43 | * produced by the relay_session). Hence, if the producer performs |
| 44 | * multiple rotations before a viewer completes the consumption of a |
| 45 | * trace chunk, it will skip over those "intermediary" trace chunks. |
| 46 | * |
| 47 | * A viewer session updates its current trace chunk when: |
| 48 | * 1) new viewer streams are created, |
| 49 | * 2) a new index is requested, |
| 50 | * 3) metadata is requested. |
| 51 | * |
| 52 | * Hence, as a general principle, the viewer session will reference the |
| 53 | * most recent trace chunk available _even if its streams do not point to |
| 54 | * it_. It indicates which trace chunk viewer streams should transition |
| 55 | * to when the end of their current trace chunk is reached. |
| 56 | * |
| 57 | * Note that a viewer session's trace chunk points to the session's |
| 58 | * output directory. The sub-directories in which the various stream files |
| 59 | * are created are considered as being a part of their name. |
| 60 | */ |
| 61 | struct lttng_trace_chunk *current_trace_chunk; |
| 62 | }; |
| 63 | |
| 64 | struct relay_viewer_session *viewer_session_create(void); |
| 65 | void viewer_session_destroy(struct relay_viewer_session *vsession); |
| 66 | void viewer_session_close(struct relay_viewer_session *vsession); |
| 67 | |
| 68 | enum lttng_viewer_attach_return_code viewer_session_attach( |
| 69 | struct relay_viewer_session *vsession, |
| 70 | struct relay_session *session); |
| 71 | int viewer_session_is_attached(struct relay_viewer_session *vsession, |
| 72 | struct relay_session *session); |
| 73 | void viewer_session_close_one_session(struct relay_viewer_session *vsession, |
| 74 | struct relay_session *session); |
| 75 | int viewer_session_set_trace_chunk_copy(struct relay_viewer_session *vsession, |
| 76 | struct lttng_trace_chunk *relay_session_trace_chunk); |
| 77 | |
| 78 | #endif /* _VIEWER_SESSION_H */ |