[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;
	struct lttng_event_desc *desc;
	int ret;

	desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
	if (!desc)
		return -ENOMEM;
	desc->name = kstrdup(name, GFP_KERNEL);
	if (!desc->name) {
		ret = -ENOMEM;
		goto error_str;
	}
	desc->nr_fields = 1;
	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;
	field->type.u.basic.integer.base = 16;
	field->type.u.basic.integer.encoding = lttng_encode_none;
	event->desc = desc;

	return 0;

error_str:
	kfree(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_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_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
	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>
	12	#include <linux/slab.h>
	13	#include "../ltt-events.h"
	14	#include "../wrapper/ringbuffer/frontend_types.h"
	15	#include "../ltt-tracer.h"
	16
	17	static
	18	int lttng_kprobes_handler_pre(struct kprobe p, struct pt_regs regs)
	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))
	28	return 0;
	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)
	33	return 0;
	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);
	37	return 0;
	38	}
	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	struct lttng_event_desc *desc;
	48	int ret;
	49
	50	desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
	51	if (!desc)
	52	return -ENOMEM;
	53	desc->name = kstrdup(name, GFP_KERNEL);
	54	if (!desc->name) {
	55	ret = -ENOMEM;
	56	goto error_str;
	57	}
	58	desc->nr_fields = 1;
	59	desc->fields = field =
	60	kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
	61	field->name = "ip";
	62	field->type.atype = atype_integer;
	63	field->type.u.basic.integer.size = sizeof(unsigned long);
	64	field->type.u.basic.integer.alignment = ltt_alignof(unsigned long);
	65	field->type.u.basic.integer.signedness = 0;
	66	field->type.u.basic.integer.reverse_byte_order = 0;
	67	field->type.u.basic.integer.base = 16;
	68	field->type.u.basic.integer.encoding = lttng_encode_none;
	69	event->desc = desc;
	70
	71	return 0;
	72
	73	error_str:
	74	kfree(desc);
	75	return ret;
	76	}
	77
	78	int lttng_kprobes_register(const char *name,
	79	const char *symbol_name,
	80	uint64_t offset,
	81	uint64_t addr,
	82	struct ltt_event *event)
	83	{
	84	int ret;
	85
	86	ret = lttng_create_kprobe_event(name, event);
	87	if (ret)
	88	goto error;
	89	memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
	90	event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
	91	event->u.kprobe.symbol_name =
	92	kzalloc(LTTNG_SYM_NAME_LEN * sizeof(char),
	93	GFP_KERNEL);
	94	if (!event->u.kprobe.symbol_name) {
	95	ret = -ENOMEM;
	96	goto name_error;
	97	}
	98	memcpy(event->u.kprobe.symbol_name, symbol_name,
	99	LTTNG_SYM_NAME_LEN * sizeof(char));
	100	event->u.kprobe.kp.symbol_name =
	101	event->u.kprobe.symbol_name;
	102	event->u.kprobe.kp.offset = offset;
	103	event->u.kprobe.kp.addr = (void *) addr;
	104	ret = register_kprobe(&event->u.kprobe.kp);
	105	if (ret)
	106	goto register_error;
	107	return 0;
	108
	109	register_error:
	110	kfree(event->u.kprobe.symbol_name);
	111	name_error:
	112	kfree(event->desc->name);
	113	kfree(event->desc);
	114	error:
	115	return ret;
	116	}
	117	EXPORT_SYMBOL_GPL(lttng_kprobes_register);
	118
	119	void lttng_kprobes_unregister(struct ltt_event *event)
	120	{
	121	unregister_kprobe(&event->u.kprobe.kp);
	122	kfree(event->u.kprobe.symbol_name);
	123	kfree(event->desc->name);
	124	kfree(event->desc);
	125	}
	126	EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
	127
	128	MODULE_LICENSE("GPL and additional rights");
	129	MODULE_AUTHOR("Mathieu Desnoyers");
	130	MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support");