Viewing file:  softdog.c (4.71 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
* http://www.redhat.com
*
* 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.
*
* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* Software only watchdog driver. Unlike its big brother the WDT501P
* driver this won't always recover a failed machine.
*
* 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> :
* Modularised.
* Added soft_margin; use upon insmod to change the timer delay.
* NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate
* minors.
*
* 19980911 Alan Cox
* Made SMP safe for 2.3.x
*
* 20011127 Joel Becker (jlbec@evilplan.org>
* Added soft_noboot; Allows testing the softdog trigger without
* requiring a recompile.
* Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT.
*/
#include <linux/module.h>
#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#define TIMER_MARGIN 60 /* (secs) Default is 1 minute */
static int soft_margin = TIMER_MARGIN; /* in seconds */
#ifdef ONLY_TESTING
static int soft_noboot = 1;
#else
static int soft_noboot = 0;
#endif /* ONLY_TESTING */
MODULE_PARM(soft_margin,"i");
MODULE_PARM(soft_noboot,"i");
MODULE_LICENSE("GPL");
/*
* Our timer
*/
static void watchdog_fire(unsigned long);
static struct timer_list watchdog_ticktock = {
function: watchdog_fire,
};
static int timer_alive;
/*
* If the timer expires..
*/
static void watchdog_fire(unsigned long data)
{
if (soft_noboot)
printk(KERN_CRIT "SOFTDOG: Triggered - Reboot ignored.\n");
else
{
printk(KERN_CRIT "SOFTDOG: Initiating system reboot.\n");
machine_restart(NULL);
printk("SOFTDOG: Reboot didn't ?????\n");
}
}
/*
* Allow only one person to hold it open
*/
static int softdog_open(struct inode *inode, struct file *file)
{
if(timer_alive)
return -EBUSY;
#ifdef CONFIG_WATCHDOG_NOWAYOUT
MOD_INC_USE_COUNT;
#endif
/*
* Activate timer
*/
mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ));
timer_alive=1;
return 0;
}
static int softdog_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer.
* Lock it in if it's a module and we defined ...NOWAYOUT
*/
lock_kernel();
#ifndef CONFIG_WATCHDOG_NOWAYOUT
del_timer(&watchdog_ticktock);
#endif
timer_alive=0;
unlock_kernel();
return 0;
}
static ssize_t softdog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
/* Can't seek (pwrite) on this device */
if (ppos != &file->f_pos)
return -ESPIPE;
/*
* Refresh the timer.
*/
if(len) {
mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ));
return 1;
}
return 0;
}
static int softdog_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int new_margin;
static struct watchdog_info ident = {
WDIOF_SETTIMEOUT,
0,
"Software Watchdog"
};
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if(copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0,(int *)arg);
case WDIOC_KEEPALIVE:
mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ));
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, (int *)arg))
return -EFAULT;
if (new_margin < 1)
return -EINVAL;
soft_margin = new_margin;
mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ));
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(soft_margin, (int *)arg);
}
}
static struct file_operations softdog_fops = {
owner: THIS_MODULE,
write: softdog_write,
ioctl: softdog_ioctl,
open: softdog_open,
release: softdog_release,
};
static struct miscdevice softdog_miscdev = {
minor: WATCHDOG_MINOR,
name: "watchdog",
fops: &softdog_fops,
};
static char banner[] __initdata = KERN_INFO "Software Watchdog Timer: 0.05, timer margin: %d sec\n";
static int __init watchdog_init(void)
{
int ret;
ret = misc_register(&softdog_miscdev);
if (ret)
return ret;
printk(banner, soft_margin);
return 0;
}
static void __exit watchdog_exit(void)
{
misc_deregister(&softdog_miscdev);
}
module_init(watchdog_init);
module_exit(watchdog_exit);
|