2 * Copyright (C) 2014 - David Goulet <dgoulet@efficios.com>
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.
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
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
18 #ifndef LTTNG_CHANNEL_H
19 #define LTTNG_CHANNEL_H
21 #include <lttng/domain.h>
22 #include <lttng/event.h>
29 * Tracer channel attributes. For both kernel and user-space.
31 * The structures should be initialized to zero before use.
33 #define LTTNG_CHANNEL_ATTR_PADDING1 LTTNG_SYMBOL_NAME_LEN + 12
34 struct lttng_channel_attr
{
35 int overwrite
; /* 1: overwrite, 0: discard */
36 uint64_t subbuf_size
; /* bytes */
37 uint64_t num_subbuf
; /* power of 2 */
38 unsigned int switch_timer_interval
; /* usec */
39 unsigned int read_timer_interval
; /* usec */
40 enum lttng_event_output output
; /* splice, mmap */
41 /* LTTng 2.1 padding limit */
42 uint64_t tracefile_size
; /* bytes */
43 uint64_t tracefile_count
; /* number of tracefiles */
44 /* LTTng 2.3 padding limit */
45 unsigned int live_timer_interval
; /* usec */
47 char padding
[LTTNG_CHANNEL_ATTR_PADDING1
];
51 * Channel information structure. For both kernel and user-space.
53 * The structures should be initialized to zero before use.
55 #define LTTNG_CHANNEL_PADDING1 16
56 struct lttng_channel
{
57 char name
[LTTNG_SYMBOL_NAME_LEN
];
59 struct lttng_channel_attr attr
;
61 char padding
[LTTNG_CHANNEL_PADDING1
];
65 * List the channel(s) of a session.
67 * The handle CAN NOT be NULL.
69 * Return the size (number of entries) of the "lttng_channel" array. Caller
70 * must free channels. On error, a negative LTTng error code is returned.
72 extern int lttng_list_channels(struct lttng_handle
*handle
,
73 struct lttng_channel
**channels
);
76 * Create or enable a channel.
78 * The chan and handle params can not be NULL.
80 * Return 0 on success else a negative LTTng error code.
82 extern int lttng_enable_channel(struct lttng_handle
*handle
,
83 struct lttng_channel
*chan
);
88 * Name and handle CAN NOT be NULL.
90 * Return 0 on success else a negative LTTng error code.
92 extern int lttng_disable_channel(struct lttng_handle
*handle
,
96 * Set the default channel attributes for a specific domain and an allocated
97 * lttng_channel_attr pointer.
99 * If one or both arguments are NULL, nothing happens.
101 extern void lttng_channel_set_default_attr(struct lttng_domain
*domain
,
102 struct lttng_channel_attr
*attr
);
108 #endif /* LTTNG_CHANNEL_H */