[libside.git] / src / side.c

// SPDX-License-Identifier: MIT
/*
 * Copyright 2022 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#include <side/trace.h>
#include "tracer.h"
#include "rcu.h"

/* Top 8 bits reserved for kernel tracer use. */
#define SIDE_EVENT_ENABLED_KERNEL_MASK			0xFF000000
#define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK	0x80000000

/* Allow 2^24 tracers to be registered on an event. */
#define SIDE_EVENT_ENABLED_USER_MASK			0x00FFFFFF

struct side_rcu_gp_state rcu_gp;

/*
 * Lazy initialization for early use within library constructors.
 */
static bool initialized;

static
void side_init(void)
	__attribute__((constructor));

const struct side_callback side_empty_callback;

void side_call(const struct side_event_description *desc, const struct side_arg_vec_description *sav_desc)
{
	const struct side_callback *side_cb;
	unsigned int rcu_period;

	if (side_unlikely(!initialized))
		side_init();
	if (side_unlikely(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) {
		printf("ERROR: unexpected variadic event description\n");
		abort();
	}
	if (side_unlikely(*desc->enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
		// TODO: call kernel write.
	}
	if (side_unlikely(!(*desc->enabled & SIDE_EVENT_ENABLED_USER_MASK)))
		return;

	//TODO: replace tracer_call by rcu iteration on list of registered callbacks
	tracer_call(desc, sav_desc, NULL);

	rcu_period = side_rcu_read_begin(&rcu_gp);
	for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call != NULL; side_cb++)
		side_cb->u.call(desc, sav_desc, side_cb->priv);
	side_rcu_read_end(&rcu_gp, rcu_period);
}

void side_call_variadic(const struct side_event_description *desc,
	const struct side_arg_vec_description *sav_desc,
	const struct side_arg_dynamic_event_struct *var_struct)
{
	const struct side_callback *side_cb;
	unsigned int rcu_period;

	if (side_unlikely(!initialized))
		side_init();
	if (side_unlikely(*desc->enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
		// TODO: call kernel write.
	}
	if (side_unlikely(!(*desc->enabled & SIDE_EVENT_ENABLED_USER_MASK)))
		return;

	//TODO: replace tracer_call by rcu iteration on list of registered callbacks
	tracer_call_variadic(desc, sav_desc, var_struct, NULL);

	rcu_period = side_rcu_read_begin(&rcu_gp);
	for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call_variadic != NULL; side_cb++)
		side_cb->u.call_variadic(desc, sav_desc, var_struct, side_cb->priv);
	side_rcu_read_end(&rcu_gp, rcu_period);
}

void side_init(void)
{
	if (initialized)
		return;
	side_rcu_gp_init(&rcu_gp);
	initialized = true;
}
Commit	Line	Data
6841ae81 MD	1	// SPDX-License-Identifier: MIT
	2	/*
	3	* Copyright 2022 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*/
	5
	6	#include <side/trace.h>
	7	#include "tracer.h"
85b765b8	8	#include "rcu.h"
6841ae81	9
054b7b5c MD	10	/* Top 8 bits reserved for kernel tracer use. */
054b7b5c MD	11	#define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF000000
29b3374e MD	12	#define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x80000000
29b3374e MD	13
054b7b5c MD	14	/* Allow 2^24 tracers to be registered on an event. */
	15	#define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFF
	16
	17	struct side_rcu_gp_state rcu_gp;
075ceef7 MD	18
	19	/*
	20	* Lazy initialization for early use within library constructors.
	21	*/
	22	static bool initialized;
	23
	24	static
	25	void side_init(void)
	26	__attribute__((constructor));
	27
054b7b5c MD	28	const struct side_callback side_empty_callback;
054b7b5c MD	29
6841ae81 MD	30	void side_call(const struct side_event_description desc, const struct side_arg_vec_description sav_desc)
6841ae81 MD	31	{
054b7b5c MD	32	const struct side_callback *side_cb;
	33	unsigned int rcu_period;
	34
075ceef7 MD	35	if (side_unlikely(!initialized))
075ceef7 MD	36	side_init();
6841ae81 MD	37	if (side_unlikely(desc->flags & SIDE_EVENT_FLAG_VARIADIC)) {
	38	printf("ERROR: unexpected variadic event description\n");
	39	abort();
	40	}
d5cdb129	41	if (side_unlikely(*desc->enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
dda82f46	42	// TODO: call kernel write.
6841ae81	43	}
054b7b5c MD	44	if (side_unlikely(!(*desc->enabled & SIDE_EVENT_ENABLED_USER_MASK)))
	45	return;
	46
6841ae81	47	//TODO: replace tracer_call by rcu iteration on list of registered callbacks
4a7d8700	48	tracer_call(desc, sav_desc, NULL);
054b7b5c MD	49
	50	rcu_period = side_rcu_read_begin(&rcu_gp);
	51	for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call != NULL; side_cb++)
	52	side_cb->u.call(desc, sav_desc, side_cb->priv);
	53	side_rcu_read_end(&rcu_gp, rcu_period);
6841ae81 MD	54	}
	55
	56	void side_call_variadic(const struct side_event_description *desc,
	57	const struct side_arg_vec_description *sav_desc,
	58	const struct side_arg_dynamic_event_struct *var_struct)
	59	{
054b7b5c MD	60	const struct side_callback *side_cb;
	61	unsigned int rcu_period;
	62
075ceef7 MD	63	if (side_unlikely(!initialized))
075ceef7 MD	64	side_init();
d5cdb129	65	if (side_unlikely(*desc->enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
dda82f46	66	// TODO: call kernel write.
6841ae81	67	}
054b7b5c MD	68	if (side_unlikely(!(*desc->enabled & SIDE_EVENT_ENABLED_USER_MASK)))
	69	return;
	70
6841ae81	71	//TODO: replace tracer_call by rcu iteration on list of registered callbacks
4a7d8700	72	tracer_call_variadic(desc, sav_desc, var_struct, NULL);
054b7b5c MD	73
	74	rcu_period = side_rcu_read_begin(&rcu_gp);
	75	for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call_variadic != NULL; side_cb++)
	76	side_cb->u.call_variadic(desc, sav_desc, var_struct, side_cb->priv);
	77	side_rcu_read_end(&rcu_gp, rcu_period);
6841ae81	78	}
075ceef7 MD	79
	80	void side_init(void)
	81	{
	82	if (initialized)
	83	return;
054b7b5c	84	side_rcu_gp_init(&rcu_gp);
075ceef7 MD	85	initialized = true;
075ceef7 MD	86	}