Use mask instead of modulo, since bo->backoff is always power of 2

[dfdiff.git] / sys / boot / forth / loader.4th.8

.\" Copyright (c) 1999 Daniel C. Sobral
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" $FreeBSD: src/sys/boot/forth/loader.4th.8,v 1.14 2002/08/13 15:09:33 ru Exp $
.\" $DragonFly: src/sys/boot/forth/loader.4th.8,v 1.4 2004/12/20 13:13:19 joerg Exp $
.\"
.Dd April 25, 1999
.Dt LOADER.4TH 8
.Os
.Sh NAME
.Nm loader.4th
.Nd loader.conf processing tools
.Sh DESCRIPTION
The file that goes by the name of
.Nm
is a set of commands designed to manipulate
.Xr loader.conf 5
files.
The default
.Pa /boot/loader.rc
includes
.Nm
and uses one of its commands to automatically read and process
the standard
.Xr loader.conf 5
files.
Other commands exists to help the user specify alternate
configurations.
.Pp
The commands of
.Nm
by themselves are not enough for most uses.
Please refer to the
examples below for the most common situations, and to
.Xr loader 8
for additional commands.
.Pp
Before using any of the commands provided in
.Nm ,
it must be included
through the command:
.Pp
.Dl include loader.4th
.Pp
This line is present in the default
.Pa /boot/loader.rc
file, so it isn't needed (and should not be re-issued) in a normal setup.
.Pp
The commands provided by it are:
.Bl -tag -width disable-module_module -compact -offset indent
.It Ic boot
.It Ic boot Ar kernelname Op Cm ...
.It Ic boot Ar directory Op Cm ...
.It Ic boot Fl flag Cm ...
Boot as specified by the
.Xr loader.conf 5
files read.
.Pp
Depending on the arguments passed, it can override boot flags and
either the kernel name or the search path for kernel and modules.
.Pp
.It Ic boot-conf
.It Ic boot-conf Ar kernelname Op Cm ...
.It Ic boot-conf Ar directory Op Cm ...
.It Ic boot-conf Fl flag Cm ...
Works like
.Ic boot
described above, but instead of booting immediately, uses
.Ic autoboot ,
so it can be stopped.
.Pp
.It Ic start
Reads
.Pa /boot/defaults/loader.conf ,
all other
.Xr loader.conf 5
files specified in it, and then proceeds to boot as specified in them.
This
is the command used in the default
.Pa /boot/loader.rc
file, and it uses the
.Pa autoboot
command (see
.Xr loader 8 ) ,
so it can be stopped for further interaction with
.Xr loader 8 .
.Pp
.It Ic initialize
Initialize the supporting library so commands can be used without
executing
.Ic start
first.
Like
.Ic start ,
reads
.Pa /boot/defaults/loader.conf
and all other
.Xr loader.conf 5
files specified in it.
Returns a flag on the stack to indicate
if any configuration file was successfully loaded.
.Pp
.It Ic read-conf Ar filename
Reads and processes a
.Xr loader.conf 5
file.
Does not proceed to boot.
.Pp
.It Ic enable-module Ar module
Enables the loading of
.Ar module .
.Pp
.It Ic disable-module Ar module
Disables the loading of
.Ar module .
.Pp
.It Ic toggle-module Ar module
Toggles the loading of
.Ar module
on and off.
.Pp
.It Ic show-module Ar module
Shows the information gathered in the
.Xr loader.conf 5
files about the module
.Ar module .
.Pp
.It Ic retry
Used inside
.Xr loader.conf 5
files to specify the action after a module loading fails.
.Pp
.It Ic ignore
Used inside
.Xr loader.conf 5
files to specify the action after a module loading fails.
.El
.Sh FILES
.Bl -tag -width /boot/loader.4th -compact
.It Pa /boot/loader
The
.Xr loader 8 .
.It Pa /boot/loader.4th
.Nm
itself.
.It Pa /boot/loader.rc
.Xr loader 8
bootstrapping script.
.It Pa /boot/defaults/loader.conf
File loaded by the
.Ic start
command.
.El
.Sh EXAMPLES
Standard
.Pa /boot/loader.rc :
.Pp
.Bd -literal -offset indent -compact
include /boot/loader.4th
start
.Ed
.Pp
Load a different kernel with the standard configuration:
.Pp
.Bd -literal -offset indent -compact
set kernel="/kernel.old"
unload
boot-conf
.Ed
.Pp
Read an additional configuration file and then proceed to boot:
.Pp
.Bd -literal -offset indent -compact
unload
read-conf /boot/special.conf
boot-conf
.Ed
.Pp
Disable the loading of the splash screen module and bitmap and then
proceed to boot:
.Pp
.Bd -literal -offset indent -compact
unload
disable-module splash_bmp
disable-module bitmap
boot-conf
.Ed
.Sh SEE ALSO
.Xr loader.conf 5 ,
.Xr loader 8
.Sh HISTORY
The
.Nm
set of commands first appeared in
.Fx 3.2 .
.Sh AUTHORS
The
.Nm
set of commands was written by
.An Daniel C. Sobral Aq dcs@FreeBSD.org .
.Sh BUGS
A British espionage series.