Split lttng.h into several files
[lttng-tools.git] / include / lttng / session.h
1 /*
2 * Copyright (C) 2014 - David Goulet <dgoulet@efficios.com>
3 *
4 * This library is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU Lesser General Public License, version 2.1 only,
6 * as published by the Free Software Foundation.
7 *
8 * This library is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
11 * for more details.
12 *
13 * You should have received a copy of the GNU Lesser General Public License
14 * along with this library; if not, write to the Free Software Foundation,
15 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
16 */
17
18 #ifndef LTTNG_SESSION_H
19 #define LTTNG_SESSION_H
20
21 #ifdef __cplusplus
22 extern "C" {
23 #endif
24
25 /*
26 * Basic session information.
27 *
28 * The "enabled" field is only used when listing the sessions which indicate if
29 * it's started or not.
30 *
31 * The structures should be initialized to zero before use.
32 */
33 #define LTTNG_SESSION_PADDING1 12
34 struct lttng_session {
35 char name[NAME_MAX];
36 /* The path where traces are written */
37 char path[PATH_MAX];
38 uint32_t enabled; /* enabled/started: 1, disabled/stopped: 0 */
39 uint32_t snapshot_mode;
40 unsigned int live_timer_interval; /* usec */
41
42 char padding[LTTNG_SESSION_PADDING1];
43 };
44
45 /*
46 * Create a tracing session using a name and an optional URL.
47 *
48 * If _url_ is NULL, no consumer is created for the session. The name can't be
49 * NULL here.
50 *
51 * Return 0 on success else a negative LTTng error code.
52 */
53 extern int lttng_create_session(const char *name, const char *url);
54
55 /*
56 * Create a tracing session that will exclusively be used for snapshot meaning
57 * the session will be in no output mode and every channel enabled for that
58 * session will be set in overwrite mode and in mmap output since splice is not
59 * supported.
60 *
61 * Name can't be NULL. If an url is given, it will be used to create a default
62 * snapshot output using it as a destination. If NULL, no output will be
63 * defined and an add-output call will be needed.
64 *
65 * Return 0 on success else a negative LTTng error code.
66 */
67 extern int lttng_create_session_snapshot(const char *name,
68 const char *snapshot_url);
69
70 /*
71 * Create a session exclusively used for live reading.
72 *
73 * In this mode, the switch-timer parameter is forced for each UST channel, a
74 * live-switch-timer is enabled for kernel channels, manually setting
75 * switch-timer is forbidden. Synchronization beacons are sent to the relayd,
76 * indexes are sent and metadata is checked for each packet.
77 *
78 * Name can't be NULL. If no URL is given, the default is to send the data to
79 * net://127.0.0.1. The timer_interval is in usec and by default set to 1000000
80 * (1 second).
81 *
82 * Return 0 on success else a negative LTTng error code.
83 */
84 extern int lttng_create_session_live(const char *name, const char *url,
85 unsigned int timer_interval);
86
87 /*
88 * Destroy a tracing session.
89 *
90 * The session will not be usable, tracing will be stopped thus buffers will be
91 * flushed.
92 *
93 * The name can't be NULL here.
94 *
95 * Return 0 on success else a negative LTTng error code.
96 */
97 extern int lttng_destroy_session(const char *name);
98
99 /*
100 * List all the tracing sessions.
101 *
102 * Return the size (number of entries) of the "lttng_session" array. Caller
103 * must free sessions. On error, a negative LTTng error code is returned.
104 */
105 extern int lttng_list_sessions(struct lttng_session **sessions);
106
107 #ifdef __cplusplus
108 }
109 #endif
110
111 #endif /* LTTNG_SESSION_H */
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