1 /* $OpenBSD: kern_watchdog.c,v 1.16 2022/08/14 01:58:27 jsg 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/systm.h> 28 #include <sys/timeout.h> 29 #include <sys/sysctl.h> 30 31 void wdog_tickle(void *arg); 32 int (*wdog_ctl_cb)(void *, int) = NULL; 33 void *wdog_ctl_cb_arg = NULL; 34 int wdog_period = 0; 35 int wdog_auto = 1; 36 struct timeout wdog_timeout; 37 38 void 39 wdog_register(int (*cb)(void *, int), void *cb_arg) 40 { 41 if (wdog_ctl_cb != NULL) 42 return; 43 44 wdog_ctl_cb = cb; 45 wdog_ctl_cb_arg = cb_arg; 46 timeout_set(&wdog_timeout, wdog_tickle, NULL); 47 } 48 49 void 50 wdog_tickle(void *arg) 51 { 52 if (wdog_ctl_cb == NULL) 53 return; 54 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, wdog_period); 55 timeout_add_msec(&wdog_timeout, wdog_period * 1000 / 2); 56 } 57 58 void 59 wdog_shutdown(void *arg) 60 { 61 if (wdog_ctl_cb == NULL || wdog_ctl_cb_arg != arg) 62 return; 63 timeout_del(&wdog_timeout); 64 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, 0); 65 wdog_ctl_cb = NULL; 66 wdog_period = 0; 67 wdog_auto = 1; 68 } 69 70 int 71 sysctl_wdog(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp, 72 size_t newlen) 73 { 74 int error, period; 75 76 if (wdog_ctl_cb == NULL) 77 return (EOPNOTSUPP); 78 79 switch (name[0]) { 80 case KERN_WATCHDOG_PERIOD: 81 period = wdog_period; 82 error = sysctl_int_bounded(oldp, oldlenp, newp, newlen, 83 &period, 0, INT_MAX); 84 if (error) 85 return (error); 86 if (newp) { 87 timeout_del(&wdog_timeout); 88 wdog_period = (*wdog_ctl_cb)(wdog_ctl_cb_arg, period); 89 } 90 break; 91 case KERN_WATCHDOG_AUTO: 92 error = sysctl_int_bounded(oldp, oldlenp, newp, newlen, 93 &wdog_auto, 0, 1); 94 if (error) 95 return (error); 96 break; 97 default: 98 return (EINVAL); 99 } 100 101 if (wdog_auto && wdog_period > 0) { 102 (void) (*wdog_ctl_cb)(wdog_ctl_cb_arg, wdog_period); 103 timeout_add_msec(&wdog_timeout, wdog_period * 1000 / 2); 104 } else 105 timeout_del(&wdog_timeout); 106 107 return (error); 108 } 109