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diff --git a/share/man/man9/watchdog.9 b/share/man/man9/watchdog.9 new file mode 100644 index 000000000000..25634c9055c9 --- /dev/null +++ b/share/man/man9/watchdog.9 @@ -0,0 +1,81 @@ +.\" +.\" Copyright (c) 2004 Poul-Henning Kamp <phk@FreeBSD.org +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, +.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd February 28, 2004 +.Dt WATCHDOG 9 +.Os +.Sh NAME +.Nm watchdog +.Nd "software and hardware watchdog facility" +.Sh SYNOPSIS +.In sys/watchdog.h +.Ft void +.Fn watchdog_fn "void *private" "u_int cmd" "int *error" +.Fn EVENTHANDLER_REGISTER watchdog_list watchdog_fn private 0 +.Fn EVENTHANDLER_DEREGISTER watchdog_list eventhandler_tag +.Sh DESCRIPTION +To implement a watchdog in software or hardware, only a single +function needs to be written and registered on the global +.Va watchdog_list . +.Pp +The function must examine the +.Fa cmd +argument and act on it as +follows: +.Pp +If +.Fa cmd +is zero, the watchdog must be disabled and the +.Fa error +argument left untouched. +If the watchdog cannot be disabled, the +.Fa error +argument must be set to +.Dv EOPNOTSUPP . +.Pp +Else the watchdog should be reset and configured to a timeout of +.Pq 1 << Pq Fa cmd No & Dv WD_INTERVAL +nanoseconds or larger and the +.Fa error +argument be set to zero to signal arming of a watchdog. +.Pp +If the watchdog cannot be configured to the proposed timeout, it +must be disabled and the +.Fa error +argument left as is (to avoid hiding the arming of another watchdog). +.Pp +There is no specification of what the watchdog should do when it +times out, but a hardware reset or similar +.Dq "drastic but certain" +behaviour is recommended. +.Sh SEE ALSO +.Xr watchdog 4 +.Sh AUTHORS +.An -nosplit +The +.Nm +facility and this manual page was written +.An Poul-Henning Kamp Aq phk@FreeBSD.org . |