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