keynotifier

keynotifier-trace.h

#if !defined(_KEYNOTIFIER_H) || defined(TRACE_HEADER_MULTI_READ)
#define _KEYNOTIFIER_H

#include <linux/tracepoint.h>

TRACE_EVENT(keynotifier_press,

    TP_PROTO(int value),

    TP_ARGS(value),

    TP_STRUCT__entry(
        __field( int, value )
    ),

    TP_fast_assign(
        __entry->value = value;
    ),

    TP_printk("Key value %d", __entry->value)
);
#endif

#undef TRACE_INCLUDE_PATH
#undef TRACE_INCLUDE_FILE
#define TRACE_INCLUDE_PATH .
#define TRACE_INCLUDE_FILE keynotifier-trace
#include <trace/define_trace.h>

keynotifier.c

/* Keynotifier - keyboard press notifier
 *
 * Copyright (C) 2014  Alex Dzyoba <avd@reduct.ru>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 */

#include "keynotifier.h"

#define CREATE_TRACE_POINTS
#include "keynotifier-trace.h"

// Keyboard notification callback
static int kb_nf_callback(struct notifier_block *nb, unsigned long code, void *_param)
{
	struct keyboard_notifier_param *param = NULL;

	param = (struct keyboard_notifier_param *)_param;

	if (!param)
	{
		pr_err("Bad keyboard notification\n");
		return NOTIFY_BAD;
	}

	if (param->down && code == KBD_KEYCODE)
    {
        pr_info("Key: %d\n", param->value);
        trace_keynotifier_press(param->value);
    }

	return NOTIFY_DONE;
}

static void cleanup(void)
{
	int rc = 0;
	
	rc = unregister_keyboard_notifier(&kb_nf);
	if (rc)
	{
		pr_err("Failed to unregister keyboard notifier. Error %d\n", rc);
	}

	return;
}

static void probe_tracepoint(void *ignore, int value)
{
    pr_alert("Key value %d\n", value);
}

static int keynotifier_init(void)
{
	int rc = 0;

    rc = register_trace_keynotifier_press(probe_tracepoint, NULL);

	rc = register_keyboard_notifier(&kb_nf);
	if (rc)
	{
		pr_err("Failed to register keyboard notifier. Error %d\n", rc);
        cleanup();
        return -EFAULT;
	}


	return 0;
}

static void keynotifier_exit(void)
{
	cleanup();
	return;
}

module_init(keynotifier_init);
module_exit(keynotifier_exit);

MODULE_AUTHOR("Alex Dzyoba <avd@reduct.ru>");
MODULE_DESCRIPTION("Keyboard press notifier");
MODULE_LICENSE("GPL");

keynotifier.h

/*
 * Keynotifier - keyboard press notifier
 *
 * Copyright (C) 2014  Alex Dzyoba <avd@reduct.ru>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 */

#include <linux/module.h>	/* Needed by all modules */
#include <linux/kernel.h>	/* Needed for KERN_INFO */
#include <linux/init.h>		/* Needed for the init macros */

#include <linux/keyboard.h> /* Needed for                   */
#include <linux/notifier.h> /*            keyboard notifier */
#include <linux/hardirq.h>

// -----------------------------------------------------------------------------
// Keyboard notifier
// -----------------------------------------------------------------------------
static int kb_nf_callback(struct notifier_block *nb, unsigned long code, void *_param);
static struct notifier_block kb_nf = {
	.notifier_call = kb_nf_callback
};

Makefile

CFLAGS_keynotifier.o := -I$(src)

obj-m := keynotifier.o

KDIR := /lib/modules/$(shell uname -r)/build

module:
	$(MAKE) -C $(KDIR) M=$(PWD) modules

clean:
	$(MAKE) -C $(KDIR) M=$(PWD) clean