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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 | /* * 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 */ #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/init.h> #include <asm/uaccess.h> #define TIMER_MARGIN 60 /* (secs) Default is 1 minute */ static int soft_margin = TIMER_MARGIN; /* in seconds */ #ifdef MODULE MODULE_PARM(soft_margin,"i"); #endif /* * Our timer */ struct timer_list watchdog_ticktock; static int timer_alive = 0; /* * If the timer expires.. */ static void watchdog_fire(unsigned long data) { #ifdef ONLY_TESTING printk(KERN_CRIT "SOFTDOG: Would Reboot.\n"); #else printk(KERN_CRIT "SOFTDOG: Initiating system reboot.\n"); machine_restart(NULL); printk("WATCHDOG: Reboot didn't ?????\n"); #endif } /* * Allow only one person to hold it open */ static int softdog_open(struct inode *inode, struct file *file) { if(timer_alive) return -EBUSY; MOD_INC_USE_COUNT; /* * 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 */ #ifndef CONFIG_WATCHDOG_NOWAYOUT del_timer(&watchdog_ticktock); MOD_DEC_USE_COUNT; #endif timer_alive=0; 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) { static struct watchdog_info ident= { 0, 0, "Software Watchdog" }; switch(cmd) { default: return -ENOIOCTLCMD; 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; } } static struct file_operations softdog_fops= { write: softdog_write, ioctl: softdog_ioctl, open: softdog_open, release: softdog_release, }; static struct miscdevice softdog_miscdev= { WATCHDOG_MINOR, "watchdog", &softdog_fops }; void __init watchdog_init(void) { misc_register(&softdog_miscdev); init_timer(&watchdog_ticktock); watchdog_ticktock.function=watchdog_fire; printk("Software Watchdog Timer: 0.05, timer margin: %d sec\n", soft_margin); } #ifdef MODULE int init_module(void) { watchdog_init(); return 0; } void cleanup_module(void) { misc_deregister(&softdog_miscdev); } #endif |