110 lines
2.3 KiB
C
110 lines
2.3 KiB
C
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/*
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* Author: andip71, 17.11.2012
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/kobject.h>
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#include <linux/sysfs.h>
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#include "printk_interface.h"
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int printk_mode;
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/* sysfs interface for printk mode */
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static ssize_t printk_mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
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{
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// print current mode
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if (printk_mode == 0)
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{
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return sprintf(buf, "printk mode: %d (disabled)", printk_mode);
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}
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else
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{
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return sprintf(buf, "printk mode: %d (enabled)", printk_mode);
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}
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}
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static ssize_t printk_mode_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count)
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{
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unsigned int ret = -EINVAL;
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int val;
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// read value from input buffer
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ret = sscanf(buf, "%d", &val);
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// check value and store if valid
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if ((val == 0) || (val == 1))
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{
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printk_mode = val;
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}
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return count;
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}
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/* Initialize printk_mode sysfs folder */
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static struct kobj_attribute printk_mode_attribute =
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__ATTR(printk_mode, 0644, printk_mode_show, printk_mode_store);
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static struct attribute *printk_mode_attrs[] = {
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&printk_mode_attribute.attr,
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NULL,
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};
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static struct attribute_group printk_mode_attr_group = {
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.attrs = printk_mode_attrs,
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};
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static struct kobject *printk_mode_kobj;
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static int __init printk_mode_init(void)
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{
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int printk_mode_retval;
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printk_mode_kobj = kobject_create_and_add("printk_mode", kernel_kobj);
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if (!printk_mode_kobj) {
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return -ENOMEM;
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}
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printk_mode_retval = sysfs_create_group(printk_mode_kobj, &printk_mode_attr_group);
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if (printk_mode_retval)
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{
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kobject_put(printk_mode_kobj);
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}
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// initialize printk mode to 1 (enabled) as default
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printk_mode = 1;
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return (printk_mode_retval);
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}
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static void __exit printk_mode_exit(void)
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{
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kobject_put(printk_mode_kobj);
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}
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/* define driver entry points */
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module_init(printk_mode_init);
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module_exit(printk_mode_exit);
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