[lttng-modules.git] / probes / lttng-kprobes.c

/*
 * (C) Copyright	2009-2011 -
 * 		Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * LTTng kprobes integration module.
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

#include <linux/module.h>
#include <linux/kprobes.h>
#include <linux/slab.h>
#include "../ltt-events.h"
#include "../wrapper/ringbuffer/frontend_types.h"
#include "../ltt-tracer.h"

static
int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
{
	struct ltt_event *event =
		container_of(p, struct ltt_event, u.kprobe.kp);
	struct ltt_channel *chan = event->chan;
	struct lib_ring_buffer_ctx ctx;
	int ret;
	unsigned long data = (unsigned long) p->addr;

	if (!ACCESS_ONCE(chan->session->active))
		return 0;
	lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data),
				 ltt_alignof(data), -1);
	ret = chan->ops->event_reserve(&ctx);
	if (ret < 0)
		return 0;
	lib_ring_buffer_align_ctx(&ctx, ltt_alignof(data));
	chan->ops->event_write(&ctx, &data, sizeof(data));
	chan->ops->event_commit(&ctx);
	return 0;
}

/*
 * Create event description
 */
static
int lttng_create_kprobe_event(const char *name, struct ltt_event *event)
{
	struct lttng_event_field *field;
	int ret;

	event->desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
	if (!event->desc)
		return -ENOMEM;
	event->desc->name = kstrdup(name, GFP_KERNEL);
	if (!event->desc->name) {
		ret = -ENOMEM;
		goto error_str;
	}
	event->desc->nr_fields = 1;
	event->desc->fields = field =
		kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
	field->name = "ip";
	field->type.atype = atype_integer;
	field->type.u.basic.integer.size = sizeof(unsigned long);
	field->type.u.basic.integer.alignment = ltt_alignof(unsigned long);
	field->type.u.basic.integer.signedness = 0;
	field->type.u.basic.integer.reverse_byte_order = 0;

	return 0;

error_str:
	kfree(event->desc);
	return ret;
}

int lttng_kprobes_register(const char *name,
			   const char *symbol_name,
			   uint64_t offset,
			   uint64_t addr,
			   struct ltt_event *event)
{
	int ret;

	ret = lttng_create_kprobe_event(name, event);
	if (ret)
		goto error;
	memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
	event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
	event->u.kprobe.symbol_name =
		kzalloc(LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char),
			GFP_KERNEL);
	if (!event->u.kprobe.symbol_name) {
		ret = -ENOMEM;
		goto name_error;
	}
	memcpy(event->u.kprobe.symbol_name, symbol_name,
	       LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char));
	event->u.kprobe.kp.symbol_name =
		event->u.kprobe.symbol_name;
	event->u.kprobe.kp.offset = offset;
	event->u.kprobe.kp.addr = (void *) addr;
	ret = register_kprobe(&event->u.kprobe.kp);
	if (ret)
		goto register_error;
	return 0;

register_error:
	kfree(event->u.kprobe.symbol_name);
name_error:
	kfree(event->desc->name);
	kfree(event->desc);
error:
	return ret;
}
EXPORT_SYMBOL_GPL(lttng_kprobes_register);

void lttng_kprobes_unregister(struct ltt_event *event)
{
	unregister_kprobe(&event->u.kprobe.kp);
	kfree(event->u.kprobe.symbol_name);
	kfree(event->desc->name);
	kfree(event->desc);
}
EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support");
Commit	Line	Data
d6d808f3 MD	1	/*
	2	* (C) Copyright 2009-2011 -
	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
	5	* LTTng kprobes integration module.
	6	*
	7	* Dual LGPL v2.1/GPL v2 license.
	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/kprobes.h>
f17701fb	12	#include <linux/slab.h>
d6d808f3 MD	13	#include "../ltt-events.h"
	14	#include "../wrapper/ringbuffer/frontend_types.h"
	15	#include "../ltt-tracer.h"
	16
f17701fb MD	17	static
f17701fb MD	18	int lttng_kprobes_handler_pre(struct kprobe p, struct pt_regs regs)
d6d808f3 MD	19	{
	20	struct ltt_event *event =
	21	container_of(p, struct ltt_event, u.kprobe.kp);
	22	struct ltt_channel *chan = event->chan;
	23	struct lib_ring_buffer_ctx ctx;
	24	int ret;
	25	unsigned long data = (unsigned long) p->addr;
	26
	27	if (!ACCESS_ONCE(chan->session->active))
f17701fb	28	return 0;
d6d808f3 MD	29	lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data),
	30	ltt_alignof(data), -1);
	31	ret = chan->ops->event_reserve(&ctx);
	32	if (ret < 0)
f17701fb	33	return 0;
d6d808f3 MD	34	lib_ring_buffer_align_ctx(&ctx, ltt_alignof(data));
	35	chan->ops->event_write(&ctx, &data, sizeof(data));
	36	chan->ops->event_commit(&ctx);
f17701fb	37	return 0;
d6d808f3	38	}
f17701fb MD	39
	40	/*
	41	* Create event description
	42	*/
	43	static
	44	int lttng_create_kprobe_event(const char name, struct ltt_event event)
	45	{
	46	struct lttng_event_field *field;
	47	int ret;
	48
	49	event->desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
	50	if (!event->desc)
	51	return -ENOMEM;
	52	event->desc->name = kstrdup(name, GFP_KERNEL);
	53	if (!event->desc->name) {
	54	ret = -ENOMEM;
	55	goto error_str;
	56	}
	57	event->desc->nr_fields = 1;
	58	event->desc->fields = field =
	59	kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
	60	field->name = "ip";
	61	field->type.atype = atype_integer;
	62	field->type.u.basic.integer.size = sizeof(unsigned long);
	63	field->type.u.basic.integer.alignment = ltt_alignof(unsigned long);
	64	field->type.u.basic.integer.signedness = 0;
	65	field->type.u.basic.integer.reverse_byte_order = 0;
	66
	67	return 0;
	68
	69	error_str:
	70	kfree(event->desc);
	71	return ret;
	72	}
	73
	74	int lttng_kprobes_register(const char *name,
	75	const char *symbol_name,
	76	uint64_t offset,
	77	uint64_t addr,
	78	struct ltt_event *event)
	79	{
	80	int ret;
	81
	82	ret = lttng_create_kprobe_event(name, event);
	83	if (ret)
	84	goto error;
	85	memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
	86	event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
	87	event->u.kprobe.symbol_name =
	88	kzalloc(LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char),
	89	GFP_KERNEL);
	90	if (!event->u.kprobe.symbol_name) {
	91	ret = -ENOMEM;
	92	goto name_error;
	93	}
	94	memcpy(event->u.kprobe.symbol_name, symbol_name,
	95	LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char));
	96	event->u.kprobe.kp.symbol_name =
	97	event->u.kprobe.symbol_name;
	98	event->u.kprobe.kp.offset = offset;
	99	event->u.kprobe.kp.addr = (void *) addr;
	100	ret = register_kprobe(&event->u.kprobe.kp);
	101	if (ret)
	102	goto register_error;
103	return 0;
104
105	register_error:
106	kfree(event->u.kprobe.symbol_name);
107	name_error:
108	kfree(event->desc->name);
109	kfree(event->desc);
110	error:
111	return ret;
112	}
113	EXPORT_SYMBOL_GPL(lttng_kprobes_register);
114
115	void lttng_kprobes_unregister(struct ltt_event *event)
116	{
117	unregister_kprobe(&event->u.kprobe.kp);
118	kfree(event->u.kprobe.symbol_name);
119	kfree(event->desc->name);
120	kfree(event->desc);
121	}
122	EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
d6d808f3 MD	123
	124	MODULE_LICENSE("GPL and additional rights");
	125	MODULE_AUTHOR("Mathieu Desnoyers");
	126	MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support");