1 /* $OpenBSD: kern_watchdog.c,v 1.8 2010/04/20 22:05:43 tedu 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/proc.h> 30 #include <sys/sysctl.h> 31 #include <sys/time.h> 32 33 void wdog_tickle(void *arg); 34 void wdog_shutdown(void *arg); 35 int (*wdog_ctl_cb)(void *, int) = NULL; 36 void *wdog_ctl_cb_arg = NULL; 37 int wdog_period = 0; 38 int wdog_auto = 1; 39 void *wdog_cookie; 40 struct timeout wdog_timeout; 41 42 void 43 wdog_register(void *cb_arg, int (*cb)(void *, int)) 44 { 45 if (wdog_ctl_cb != NULL) 46 return; 47 48 wdog_ctl_cb = cb; 49 wdog_ctl_cb_arg = cb_arg; 50 timeout_set(&wdog_timeout, wdog_tickle, NULL); 51 wdog_cookie = shutdownhook_establish(wdog_shutdown, NULL); 52 } 53 54 void 55 wdog_tickle(void *arg) 56 { 57 if (wdog_ctl_cb == NULL) 58 return; 59 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, wdog_period); 60 timeout_add(&wdog_timeout, wdog_period * hz / 2); 61 } 62 63 void 64 wdog_shutdown(void *arg) 65 { 66 if (wdog_ctl_cb == NULL) 67 return; 68 timeout_del(&wdog_timeout); 69 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, 0); 70 wdog_ctl_cb = NULL; 71 wdog_period = 0; 72 wdog_auto = 1; 73 } 74 75 int 76 sysctl_wdog(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, 77 size_t newlen) 78 { 79 int error, period; 80 81 if (wdog_ctl_cb == NULL) 82 return (EOPNOTSUPP); 83 84 switch (name[0]) { 85 case KERN_WATCHDOG_PERIOD: 86 period = wdog_period; 87 error = sysctl_int(oldp, oldlenp, newp, newlen, &period); 88 if (error) 89 return (error); 90 if (newp) { 91 timeout_del(&wdog_timeout); 92 wdog_period = (*wdog_ctl_cb)(wdog_ctl_cb_arg, period); 93 } 94 break; 95 case KERN_WATCHDOG_AUTO: 96 error = sysctl_int(oldp, oldlenp, newp, newlen, &wdog_auto); 97 if (error) 98 return (error); 99 if (wdog_auto && wdog_cookie == NULL) 100 wdog_cookie = shutdownhook_establish(wdog_shutdown, 101 NULL); 102 else if (!wdog_auto && wdog_cookie) { 103 shutdownhook_disestablish(wdog_cookie); 104 wdog_cookie = NULL; 105 } 106 break; 107 default: 108 return (EINVAL); 109 } 110 111 if (wdog_auto && wdog_period > 0) { 112 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, wdog_period); 113 timeout_add(&wdog_timeout, wdog_period * hz / 2); 114 } else 115 timeout_del(&wdog_timeout); 116 117 return (error); 118 } 119