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/*
* Unique ID manipulation sysfs access generic functions
*
* Author: dmitry pervushin <dimka@embeddedalley.com>
*
* Copyright 2008-2010 Freescale Semiconductor, Inc.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
*/
/*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/err.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <mach/unique-id.h>
static int unlock;
static spinlock_t u_lock;
static const unsigned long UID_AUTOLOCK_TIMEOUT = HZ * 60 * 3;
static struct timer_list u_timer;
static void uid_timer_autolock(unsigned long param)
{
struct timer_list *tmr = (struct timer_list *)param;
if (spin_trylock(&u_lock)) {
if (unlock)
pr_debug("%s: locked down.\n", __func__);
unlock = 0;
spin_unlock(&u_lock);
}
mod_timer(tmr, jiffies + UID_AUTOLOCK_TIMEOUT);
}
static LIST_HEAD(uid_provider_list);
struct uid_provider {
struct kobject *kobj;
struct list_head list;
struct uid_ops *ops;
void *context;
};
static struct uid_provider *uid_provider_find(const char *name);
#define UID_FWD_SYSFS_FILE(var, file, param) \
static ssize_t var##_show(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
struct uid_provider *p = \
uid_provider_find(kobject_name(kobj)); \
ssize_t r; \
BUG_ON(p == NULL); \
r = (p->ops && p->ops->file##_show) ? \
p->ops->file##_show(p->context, buf, param) : 0;\
return r; \
} \
\
static ssize_t var##_store(struct kobject *kobj, \
struct kobj_attribute *attr, const char *buf, \
size_t count) \
{ \
struct uid_provider *p = \
uid_provider_find(kobject_name(kobj)); \
ssize_t r; \
int ul; \
BUG_ON(p == NULL); \
spin_lock(&u_lock); \
ul = unlock; \
spin_unlock(&u_lock); \
if (ul) \
r = (p->ops && p->ops->file##_store) ? \
p->ops->file##_store(p->context, buf, count, param) \
: count; \
else \
r = -EACCES; \
return r; \
}
struct kobject *uid_kobj;
#define UID_ATTR(_name, _varname) \
static struct kobj_attribute _varname##_attr = \
__ATTR(_name, 0644, _varname##_show, _varname##_store)
UID_FWD_SYSFS_FILE(id, id, 1);
UID_FWD_SYSFS_FILE(id_bin, id, 0);
UID_ATTR(id, id);
UID_ATTR(id.bin, id_bin);
static struct attribute *uid_attrs[] = {
&id_attr.attr,
&id_bin_attr.attr,
NULL
};
static struct attribute_group uid_attr_group = {
.attrs = uid_attrs,
};
struct kobject *uid_provider_init(const char *name,
struct uid_ops *ops, void *context)
{
struct uid_provider *new;
int err;
new = kzalloc(sizeof(*new), GFP_KERNEL);
if (!new) {
err = -ENOMEM;
goto out;
}
new->kobj = kobject_create_and_add(name, uid_kobj);
if (!new->kobj) {
err = -ENOMEM;
goto out;
}
new->ops = ops;
new->context = context;
err = sysfs_create_group(new->kobj, &uid_attr_group);
if (err)
goto out2;
list_add_tail(&new->list, &uid_provider_list);
return new->kobj;
out2:
kobject_del(new->kobj);
out:
kfree(new);
return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(uid_provider_init);
static struct uid_provider *uid_provider_find(const char *name)
{
struct uid_provider *p;
list_for_each_entry(p, &uid_provider_list, list) {
if (strcmp(kobject_name(p->kobj), name) == 0)
return p;
}
return NULL;
}
void uid_provider_remove(const char *name)
{
struct uid_provider *p;
p = uid_provider_find(name);
if (!p)
return;
kobject_del(p->kobj);
list_del(&p->list);
kfree(p);
}
EXPORT_SYMBOL_GPL(uid_provider_remove);
static int uid_sysfs_init(void)
{
int error;
uid_kobj = kobject_create_and_add("uid", NULL);
if (!uid_kobj) {
error = -ENOMEM;
goto out1;
}
spin_lock_init(&u_lock);
setup_timer(&u_timer, uid_timer_autolock, (unsigned long)&u_timer);
/* try to lock each 3 minutes */
mod_timer(&u_timer, jiffies + UID_AUTOLOCK_TIMEOUT);
return 0;
out1:
printk(KERN_ERR"%s failed, error %d.", __func__, error);
return error;
}
module_param(unlock, int, 0600)
core_initcall(uid_sysfs_init);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("dmitry pervushin <dimka@embeddedalley.com>");
MODULE_DESCRIPTION("Unique ID simple framework");
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