FreeBSD-5.3/usr.sbin/watchdogd/watchdogd.8

.\" Copyright (c) 2004  Poul-Henning Kamp <phk@FreeBSD.org>
.\" Copyright (c) 2003  Sean M. Kelly <smkelly@FreeBSD.org>
.\" All rights reserved.
.\"
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.\" $FreeBSD: src/usr.sbin/watchdogd/watchdogd.8,v 1.4 2004/06/13 18:03:43 ru Exp $
.\"
.Dd June 25, 2003
.Dt WATCHDOGD 8
.Os
.Sh NAME
.Nm watchdogd
.Nd watchdog daemon
.Sh SYNOPSIS
.Nm
.Op Fl d
.Op Fl e Ar cmd
.Op Fl I Ar file
.Op Fl s Ar sleep
.Op Fl t Ar timeout
.Sh DESCRIPTION
The
.Nm
utility interfaces with the kernel's watchdog facility to ensure
that the system is in a working state.
If
.Nm
is unable to interface with the kernel over a specific timeout,
the kernel will take actions to assist in debugging or restarting the computer.
.Pp
If
.Fl e Ar cmd
is specified,
.Nm
will attempt to execute this command with
.Xr system 3 ,
and only if the command returns with a zero exit code will the
watchdog be reset.
If
.Fl e Ar cmd
is not specified, the daemon will perform a trivial file system
check instead.
.Pp
The
.Fl s Ar sleep
argument can be used to control the sleep period between each execution
of the check and defaults to one second.
.Pp
The
.Fl t Ar timeout
specifies the desired timeout period in seconds.
.Pp
One possible circumstance which will cause a watchdog timeout is an interrupt
storm.
If this occurs,
.Nm
will no longer execute and thus the kernel's watchdog routines will take
action after a configurable timeout.
.Pp
Upon receiving the
.Dv SIGTERM
or
.Dv SIGINT
signals,
.Nm
will first instruct the kernel to no longer perform watchdog checks and then
will terminate.
.Pp
The
.Nm
utility recognizes the following runtime options:
.Bl -tag -width ".Fl I Ar file"
.It Fl I Ar file
Write the process ID of the
.Nm
utility in the specified file.
.It Fl d
Do not fork.
When this option is specified,
.Nm
will not fork into the background at startup.
.El
.Sh FILES
.Bl -tag -width ".Pa /var/run/watchdogd.pid" -compact
.It Pa /var/run/watchdogd.pid
.El
.Sh SEE ALSO
.Xr watchdog 4 ,
.Xr watchdog 8 ,
.Xr watchdog 9
.Sh AUTHORS
.An -nosplit
The
.Nm
utility and manual page were written by
.An Sean Kelly Aq smkelly@FreeBSD.org
and
.An Poul-Henning Kamp Aq phk@FreeBSD.org .
.Pp
Some contributions made by
.An Jeff Roberson Aq jeff@FreeBSD.org .
.Sh HISTORY
The
.Nm
utility appeared in
.Fx 5.1 .