[lttng-tools.git] / src / common / trace-chunk-registry.h

/*
 * Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * SPDX-License-Identifier: LGPL-2.1-only
 *
 */

#ifndef LTTNG_TRACE_CHUNK_REGISTRY_H
#define LTTNG_TRACE_CHUNK_REGISTRY_H

#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <common/macros.h>
#include <common/trace-chunk.h>

struct lttng_trace_chunk_registry;

/*
 * Create an lttng_trace_chunk registry.
 *
 * A trace chunk registry maintains an association between a
 * (session_id, chunk_id) tuple and a trace chunk object. The chunk_id can
 * be "unset" in the case of an anonymous trace chunk.
 *
 * Note that a trace chunk registry holds no ownership of its trace
 * chunks. Trace chunks are unpublished when their last reference is released.
 * See the documentation of lttng_trace_chunk.
 *
 * Returns a trace chunk registry on success, NULL on error.
 *
 * Note that a trace chunk registry may only be accessed by an RCU thread.
 */
LTTNG_HIDDEN
struct lttng_trace_chunk_registry *lttng_trace_chunk_registry_create(void);

/*
 * Destroy an lttng trace chunk registry. The registry must be emptied
 * (i.e. all references to the trace chunks it contains must be released) before
 * it is destroyed.
 */
LTTNG_HIDDEN
void lttng_trace_chunk_registry_destroy(
		struct lttng_trace_chunk_registry *registry);

/*
 * Publish a trace chunk for a given session id.
 * A reference is acquired on behalf of the caller.
 *
 * The trace chunk that is returned is the published version of the trace
 * chunk. The chunk provided should be discarded on success and it's
 * published version used in its place.
 *
 * See the documentation of lttng_trace_chunk for more information on
 * the usage of the various parameters.
 *
 * Returns an lttng_trace_chunk on success, NULL on error.
 */
LTTNG_HIDDEN
struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk(
		struct lttng_trace_chunk_registry *registry,
		uint64_t session_id, struct lttng_trace_chunk *chunk);

/*
 * Adds the `previously_published` parameter which allows the caller
 * to know if a trace chunk equivalent to `chunk` was previously published.
 * 
 * The registry holds a reference to the published trace chunks it contains.
 * Trace chunks automatically unpublish themselves from their registry on
 * destruction.
 *
 * This information is necessary to drop the reference of newly published
 * chunks when a user doesn't wish to explicitly maintain all references
 * to a given trace chunk.
 * 
 * For instance, the relay daemon doesn't need the registry to hold a
 * reference since it controls the lifetime of its trace chunks.
 * Conversely, the consumer daemons rely on the session daemon to inform
 * them of the end of life of a trace chunk and the trace chunks don't
 * belong to a specific top-level object: they are always retrieved from
 * the registry by `id`.
 */
struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk_published(
		struct lttng_trace_chunk_registry *registry,
		uint64_t session_id, struct lttng_trace_chunk *chunk,
		bool *previously_published);

/*
 * Look-up a trace chunk by session_id and chunk_id.
 * A reference is acquired on behalf of the caller.
 *
 * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
 */
LTTNG_HIDDEN
struct lttng_trace_chunk *
lttng_trace_chunk_registry_find_chunk(
		const struct lttng_trace_chunk_registry *registry,
		uint64_t session_id, uint64_t chunk_id);

/*
 * Query the existence of a trace chunk by session_id and chunk_id.
 *
 * Returns 0 on success, a negative value on error.
 */
LTTNG_HIDDEN
int lttng_trace_chunk_registry_chunk_exists(
		const struct lttng_trace_chunk_registry *registry,
		uint64_t session_id, uint64_t chunk_id, bool *chunk_exists);

/*
 * Look-up an anonymous trace chunk by session_id.
 * A reference is acquired on behalf of the caller.
 *
 * Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
 */
LTTNG_HIDDEN
struct lttng_trace_chunk *
lttng_trace_chunk_registry_find_anonymous_chunk(
		const struct lttng_trace_chunk_registry *registry,
		uint64_t session_id);

LTTNG_HIDDEN
unsigned int lttng_trace_chunk_registry_put_each_chunk(
		const struct lttng_trace_chunk_registry *registry);

#endif /* LTTNG_TRACE_CHUNK_REGISTRY_H */
Commit	Line	Data
2c5ff4e4	1	/*
ab5be9fa	2	* Copyright (C) 2019 Jérémie Galarneau <jeremie.galarneau@efficios.com>
2c5ff4e4	3	*
ab5be9fa	4	* SPDX-License-Identifier: LGPL-2.1-only
2c5ff4e4	5	*
2c5ff4e4 JG	6	*/
	7
	8	#ifndef LTTNG_TRACE_CHUNK_REGISTRY_H
	9	#define LTTNG_TRACE_CHUNK_REGISTRY_H
	10
	11	#include <stddef.h>
	12	#include <stdint.h>
	13	#include <stdbool.h>
	14	#include <common/macros.h>
	15	#include <common/trace-chunk.h>
	16
	17	struct lttng_trace_chunk_registry;
	18
	19	/*
	20	* Create an lttng_trace_chunk registry.
	21	*
	22	* A trace chunk registry maintains an association between a
	23	* (session_id, chunk_id) tuple and a trace chunk object. The chunk_id can
	24	* be "unset" in the case of an anonymous trace chunk.
	25	*
	26	* Note that a trace chunk registry holds no ownership of its trace
	27	* chunks. Trace chunks are unpublished when their last reference is released.
	28	* See the documentation of lttng_trace_chunk.
	29	*
	30	* Returns a trace chunk registry on success, NULL on error.
	31	*
	32	* Note that a trace chunk registry may only be accessed by an RCU thread.
	33	*/
	34	LTTNG_HIDDEN
	35	struct lttng_trace_chunk_registry *lttng_trace_chunk_registry_create(void);
	36
	37	/*
	38	* Destroy an lttng trace chunk registry. The registry must be emptied
	39	* (i.e. all references to the trace chunks it contains must be released) before
	40	* it is destroyed.
	41	*/
	42	LTTNG_HIDDEN
	43	void lttng_trace_chunk_registry_destroy(
	44	struct lttng_trace_chunk_registry *registry);
	45
	46	/*
	47	* Publish a trace chunk for a given session id.
	48	* A reference is acquired on behalf of the caller.
	49	*
	50	* The trace chunk that is returned is the published version of the trace
	51	* chunk. The chunk provided should be discarded on success and it's
	52	* published version used in its place.
	53	*
	54	* See the documentation of lttng_trace_chunk for more information on
	55	* the usage of the various parameters.
	56	*
	57	* Returns an lttng_trace_chunk on success, NULL on error.
	58	*/
	59	LTTNG_HIDDEN
	60	struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk(
	61	struct lttng_trace_chunk_registry *registry,
	62	uint64_t session_id, struct lttng_trace_chunk *chunk);
	63
84a85e3c JG	64	/*
	65	* Adds the `previously_published` parameter which allows the caller
	66	* to know if a trace chunk equivalent to `chunk` was previously published.
	67	*
	68	* The registry holds a reference to the published trace chunks it contains.
	69	* Trace chunks automatically unpublish themselves from their registry on
	70	* destruction.
	71	*
	72	* This information is necessary to drop the reference of newly published
	73	* chunks when a user doesn't wish to explicitly maintain all references
	74	* to a given trace chunk.
	75	*
	76	* For instance, the relay daemon doesn't need the registry to hold a
	77	* reference since it controls the lifetime of its trace chunks.
	78	* Conversely, the consumer daemons rely on the session daemon to inform
	79	* them of the end of life of a trace chunk and the trace chunks don't
	80	* belong to a specific top-level object: they are always retrieved from
	81	* the registry by `id`.
	82	*/
	83	struct lttng_trace_chunk *lttng_trace_chunk_registry_publish_chunk_published(
	84	struct lttng_trace_chunk_registry *registry,
	85	uint64_t session_id, struct lttng_trace_chunk *chunk,
	86	bool *previously_published);
	87
2c5ff4e4 JG	88	/*
	89	* Look-up a trace chunk by session_id and chunk_id.
	90	* A reference is acquired on behalf of the caller.
	91	*
	92	* Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
	93	*/
	94	LTTNG_HIDDEN
	95	struct lttng_trace_chunk *
	96	lttng_trace_chunk_registry_find_chunk(
	97	const struct lttng_trace_chunk_registry *registry,
	98	uint64_t session_id, uint64_t chunk_id);
	99
6b584c2e JG	100	/*
	101	* Query the existence of a trace chunk by session_id and chunk_id.
	102	*
	103	* Returns 0 on success, a negative value on error.
	104	*/
	105	LTTNG_HIDDEN
	106	int lttng_trace_chunk_registry_chunk_exists(
	107	const struct lttng_trace_chunk_registry *registry,
	108	uint64_t session_id, uint64_t chunk_id, bool *chunk_exists);
	109
2c5ff4e4 JG	110	/*
	111	* Look-up an anonymous trace chunk by session_id.
	112	* A reference is acquired on behalf of the caller.
	113	*
	114	* Returns an lttng_trace_chunk on success, NULL if the chunk does not exist.
	115	*/
	116	LTTNG_HIDDEN
	117	struct lttng_trace_chunk *
	118	lttng_trace_chunk_registry_find_anonymous_chunk(
	119	const struct lttng_trace_chunk_registry *registry,
	120	uint64_t session_id);
	121
e10aec8f MD	122	LTTNG_HIDDEN
e10aec8f MD	123	unsigned int lttng_trace_chunk_registry_put_each_chunk(
8ced4811	124	const struct lttng_trace_chunk_registry *registry);
e10aec8f	125
2c5ff4e4	126	#endif /* LTTNG_TRACE_CHUNK_REGISTRY_H */