1 /* $OpenBSD: kern_watchdog.c,v 1.7 2006/12/21 12:47:57 mbalmer Exp $ */ 2 3 /* 4 * Copyright (c) 2003 Markus Friedl. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 #include <sys/param.h> 27 #include <sys/kernel.h> 28 #include <sys/systm.h> 29 #include <sys/sysctl.h> 30 #include <sys/time.h> 31 32 void wdog_tickle(void *arg); 33 void wdog_shutdown(void *arg); 34 int (*wdog_ctl_cb)(void *, int) = NULL; 35 void *wdog_ctl_cb_arg = NULL; 36 int wdog_period = 0; 37 int wdog_auto = 1; 38 void *wdog_cookie; 39 struct timeout wdog_timeout; 40 41 void 42 wdog_register(void *cb_arg, int (*cb)(void *, int)) 43 { 44 if (wdog_ctl_cb != NULL) 45 return; 46 47 wdog_ctl_cb = cb; 48 wdog_ctl_cb_arg = cb_arg; 49 timeout_set(&wdog_timeout, wdog_tickle, NULL); 50 wdog_cookie = shutdownhook_establish(wdog_shutdown, NULL); 51 } 52 53 void 54 wdog_tickle(void *arg) 55 { 56 if (wdog_ctl_cb == NULL) 57 return; 58 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, wdog_period); 59 timeout_add(&wdog_timeout, wdog_period * hz / 2); 60 } 61 62 void 63 wdog_shutdown(void *arg) 64 { 65 if (wdog_ctl_cb == NULL) 66 return; 67 timeout_del(&wdog_timeout); 68 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, 0); 69 wdog_ctl_cb = NULL; 70 wdog_period = 0; 71 wdog_auto = 1; 72 } 73 74 int 75 sysctl_wdog(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, 76 size_t newlen) 77 { 78 int error, period; 79 80 if (wdog_ctl_cb == NULL) 81 return (EOPNOTSUPP); 82 83 switch (name[0]) { 84 case KERN_WATCHDOG_PERIOD: 85 period = wdog_period; 86 error = sysctl_int(oldp, oldlenp, newp, newlen, &period); 87 if (error) 88 return (error); 89 if (newp) { 90 timeout_del(&wdog_timeout); 91 wdog_period = (*wdog_ctl_cb)(wdog_ctl_cb_arg, period); 92 } 93 break; 94 case KERN_WATCHDOG_AUTO: 95 error = sysctl_int(oldp, oldlenp, newp, newlen, &wdog_auto); 96 if (error) 97 return (error); 98 if (wdog_auto && wdog_cookie == NULL) 99 wdog_cookie = shutdownhook_establish(wdog_shutdown, 100 NULL); 101 else if (!wdog_auto && wdog_cookie) { 102 shutdownhook_disestablish(wdog_cookie); 103 wdog_cookie = NULL; 104 } 105 break; 106 default: 107 return (EINVAL); 108 } 109 110 if (wdog_auto && wdog_period > 0) { 111 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, wdog_period); 112 timeout_add(&wdog_timeout, wdog_period * hz / 2); 113 } else 114 timeout_del(&wdog_timeout); 115 116 return (error); 117 } 118