1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
|
/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
*
* ringbuffer/iterator.h
*
* Ring buffer and channel iterators.
*
* Copyright (C) 2010-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*/
#ifndef _LIB_RING_BUFFER_ITERATOR_H
#define _LIB_RING_BUFFER_ITERATOR_H
#include <ringbuffer/backend.h>
#include <ringbuffer/frontend.h>
#include <ringbuffer/vfs.h>
/*
* lib_ring_buffer_get_next_record advances the buffer read position to the next
* record. It returns either the size of the next record, -EAGAIN if there is
* currently no data available, or -ENODATA if no data is available and buffer
* is finalized.
*/
extern ssize_t lib_ring_buffer_get_next_record(struct lttng_kernel_ring_buffer_channel *chan,
struct lttng_kernel_ring_buffer *buf);
/*
* Ensure that the current subbuffer is put after client code has read the
* payload of the current record. Has an effect when the end of subbuffer is
* reached. It is not required if get_next_record is called successively.
* However, it should be invoked before returning data to user-space to ensure
* that the get/put subbuffer state is quiescent.
*/
extern void lib_ring_buffer_put_current_record(struct lttng_kernel_ring_buffer *buf);
/*
* channel_get_next_record advances the buffer read position to the next record.
* It returns either the size of the next record, -EAGAIN if there is currently
* no data available, or -ENODATA if no data is available and buffer is
* finalized.
* Returns the current buffer in ret_buf.
*/
extern ssize_t channel_get_next_record(struct lttng_kernel_ring_buffer_channel *chan,
struct lttng_kernel_ring_buffer **ret_buf);
/**
* read_current_record - copy the buffer current record into dest.
* @buf: ring buffer
* @dest: destination where the record should be copied
*
* dest should be large enough to contain the record. Returns the number of
* bytes copied.
*/
static inline size_t read_current_record(struct lttng_kernel_ring_buffer *buf, void *dest)
{
return lib_ring_buffer_read(&buf->backend, buf->iter.read_offset,
dest, buf->iter.payload_len);
}
extern int lib_ring_buffer_iterator_open(struct lttng_kernel_ring_buffer *buf);
extern void lib_ring_buffer_iterator_release(struct lttng_kernel_ring_buffer *buf);
extern int channel_iterator_open(struct lttng_kernel_ring_buffer_channel *chan);
extern void channel_iterator_release(struct lttng_kernel_ring_buffer_channel *chan);
extern const struct file_operations channel_payload_file_operations;
extern const struct file_operations lib_ring_buffer_payload_file_operations;
/*
* Used internally.
*/
int channel_iterator_init(struct lttng_kernel_ring_buffer_channel *chan);
void channel_iterator_unregister_notifiers(struct lttng_kernel_ring_buffer_channel *chan);
void channel_iterator_free(struct lttng_kernel_ring_buffer_channel *chan);
void channel_iterator_reset(struct lttng_kernel_ring_buffer_channel *chan);
void lib_ring_buffer_iterator_reset(struct lttng_kernel_ring_buffer *buf);
#endif /* _LIB_RING_BUFFER_ITERATOR_H */
|
