12bedf807SPoul-Henning Kamp.\" 262486687SUlrich Spörlein.\" Copyright (c) 2004 Poul-Henning Kamp <phk@FreeBSD.org> 32bedf807SPoul-Henning Kamp.\" All rights reserved. 42bedf807SPoul-Henning Kamp.\" 52bedf807SPoul-Henning Kamp.\" Redistribution and use in source and binary forms, with or without 62bedf807SPoul-Henning Kamp.\" modification, are permitted provided that the following conditions 72bedf807SPoul-Henning Kamp.\" are met: 82bedf807SPoul-Henning Kamp.\" 1. Redistributions of source code must retain the above copyright 92bedf807SPoul-Henning Kamp.\" notice, this list of conditions and the following disclaimer. 102bedf807SPoul-Henning Kamp.\" 2. Redistributions in binary form must reproduce the above copyright 112bedf807SPoul-Henning Kamp.\" notice, this list of conditions and the following disclaimer in the 122bedf807SPoul-Henning Kamp.\" documentation and/or other materials provided with the distribution. 132bedf807SPoul-Henning Kamp.\" 142bedf807SPoul-Henning Kamp.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 152bedf807SPoul-Henning Kamp.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 162bedf807SPoul-Henning Kamp.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 172bedf807SPoul-Henning Kamp.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 182bedf807SPoul-Henning Kamp.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 192bedf807SPoul-Henning Kamp.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 202bedf807SPoul-Henning Kamp.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 212bedf807SPoul-Henning Kamp.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 222bedf807SPoul-Henning Kamp.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 232bedf807SPoul-Henning Kamp.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 242bedf807SPoul-Henning Kamp.\" 252bedf807SPoul-Henning Kamp.Dd February 28, 2004 266ac051ecSRuslan Ermilov.Dt WATCHDOG 9 272bedf807SPoul-Henning Kamp.Os 282bedf807SPoul-Henning Kamp.Sh NAME 292bedf807SPoul-Henning Kamp.Nm watchdog 306ac051ecSRuslan Ermilov.Nd "software and hardware watchdog facility" 312bedf807SPoul-Henning Kamp.Sh SYNOPSIS 322bedf807SPoul-Henning Kamp.In sys/watchdog.h 336ac051ecSRuslan Ermilov.Ft void 342bedf807SPoul-Henning Kamp.Fn watchdog_fn "void *private" "u_int cmd" "int *error" 356ac051ecSRuslan Ermilov.Fn EVENTHANDLER_REGISTER watchdog_list watchdog_fn private 0 369079fff5SNick Hibma.Fn EVENTHANDLER_DEREGISTER watchdog_list eventhandler_tag 372bedf807SPoul-Henning Kamp.Sh DESCRIPTION 382bedf807SPoul-Henning KampTo implement a watchdog in software or hardware, only a single 392bedf807SPoul-Henning Kampfunction needs to be written and registered on the global 406ac051ecSRuslan Ermilov.Va watchdog_list . 412bedf807SPoul-Henning Kamp.Pp 426ac051ecSRuslan ErmilovThe function must examine the 436ac051ecSRuslan Ermilov.Fa cmd 446ac051ecSRuslan Ermilovargument and act on it as 452bedf807SPoul-Henning Kampfollows: 462bedf807SPoul-Henning Kamp.Pp 476ac051ecSRuslan ErmilovIf 486ac051ecSRuslan Ermilov.Fa cmd 496ac051ecSRuslan Ermilovis zero, the watchdog must be disabled and the 506ac051ecSRuslan Ermilov.Fa error 51ffdb86feSChristian Bruefferargument left untouched. 52ffdb86feSChristian BruefferIf the watchdog cannot be disabled, the 5336eab024SNick Hibma.Fa error 5436eab024SNick Hibmaargument must be set to 5536eab024SNick Hibma.Dv EOPNOTSUPP . 562bedf807SPoul-Henning Kamp.Pp 572bedf807SPoul-Henning KampElse the watchdog should be reset and configured to a timeout of 586ac051ecSRuslan Ermilov.Pq 1 << Pq Fa cmd No & Dv WD_INTERVAL 596ac051ecSRuslan Ermilovnanoseconds or larger and the 606ac051ecSRuslan Ermilov.Fa error 6136eab024SNick Hibmaargument be set to zero to signal arming of a watchdog. 622bedf807SPoul-Henning Kamp.Pp 632bedf807SPoul-Henning KampIf the watchdog cannot be configured to the proposed timeout, it 646ac051ecSRuslan Ermilovmust be disabled and the 656ac051ecSRuslan Ermilov.Fa error 6636eab024SNick Hibmaargument left as is (to avoid hiding the arming of another watchdog). 672bedf807SPoul-Henning Kamp.Pp 682bedf807SPoul-Henning KampThere is no specification of what the watchdog should do when it 696ac051ecSRuslan Ermilovtimes out, but a hardware reset or similar 706ac051ecSRuslan Ermilov.Dq "drastic but certain" 712bedf807SPoul-Henning Kampbehaviour is recommended. 722bedf807SPoul-Henning Kamp.Sh SEE ALSO 732bedf807SPoul-Henning Kamp.Xr watchdog 4 742bedf807SPoul-Henning Kamp.Sh AUTHORS 752bedf807SPoul-Henning Kamp.An -nosplit 766ac051ecSRuslan ErmilovThe 776ac051ecSRuslan Ermilov.Nm 786ac051ecSRuslan Ermilovfacility and this manual page was written 79*8a7314fcSBaptiste Daroussin.An Poul-Henning Kamp Aq Mt phk@FreeBSD.org . 80