The attached manual page documents the syntax for the kernel configuration
files as understood by the config(8) program in 5-CURRENT. This syntax has
diverged from the syntax understood by the original 4.4BSD config(8) program,
and it is perhaps time for a new manual page.
This manual entry is to be added to section 5 (file formats) of the
FreeBSD manual.
Could you please review and send in your comments?
Joseph Koshy <[EMAIL PROTECTED]>
Developer, The FreeBSD Project http://people.freebsd.org/~jkoshy/
.\" Copyright (c) 2003 Joseph Koshy
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.\" $FreeBSD: src/share/man/man5/quota.user.5,v 1.3 2002/12/12 17:25:57 ru Exp
$
.\"
.Dd June 03, 2003
.Dt CONFIG 5
.Os
.Sh NAME
.Nm config
.Nd kernel configuration file format
.Sh DESCRIPTION
A kernel configuration file specifies the configuration of a
.Fx
kernel.
It is processed by
.Xr config 8
to create a build environment where a kernel may be built using
.Xr make 1 .
.Sh LEXICAL STRUCTURE
A kernel configuration file comprises a sequence of specification
directives.
.Pp
A specification directive starts with a keyword at the beginning
of the line and is followed by additional parameters.
.Pp
A specification directive may be terminated by a semicolon
.Ql \&;
or by a newline.
Long input lines may be broken into shorter lines by
starting the second and subsequent lines with a white
space character.
.Pp
Case is significant,
.Ql machine
and
.Ql MACHINE
are different tokens.
.Pp
A double quote character
.Ql \&\*q
starts a quoted string.
All characters up to the next quote character form the value
of the quoted string.
A
.Ql \&\*q
character may be inserted into a quoted string by
using the sequence
.Ql \e\*q .
.Pp
Number are specified using
.Li C Ns No -style
syntax.
.Pp
A
.Ql #
character starts a comment; all characters from the
.Ql #
character till end of line are ignored.
.Pp
Whitespace between tokens is ignored, except inside quoted strings.
Whitespace following a comment line is ignored.
.Sh CONFIGURATION DIRECTIVES
Kernel configuration directives may appear in any order
in a kernel configuration file.
Directives are processed in order of appearance with subsequent
directive lines overriding the effect of prior ones.
.Pp
The list of keywords and their meanings are as follows:
.Bl -tag -width "makeoptions"
.\" CPU
.It Cm cpu Ar cputype
Specify the CPU this kernel will run on.
There can be more than one
.Li cpu
directives in a configuration file.
The allowed list of cpu names is architecture specific and is
defined in the file
.Pa "sys/conf/options." Ns Ar arch .
.\" DEVICE
.It Cm device Ar name Op count
Configures device
.Ar name
for inclusion into the kernel image.
If
.Ar count
is specified, the device is configured for
.Ar count
instances.
The list of valid device names is architecture specific and are
defined in the files
.Pa "sys/conf/files"
and
.Pa "sys/conf/files." Ns Ar arch .
.\" ENV
.It Cm env Ar filename
Specifies a filename containing a kernel environment definition.
The kernel normally uses an environment prepared for it at boot time
by
.Xr loader 8 .
This directive makes the kernel ignore the boot environment and use
the compiled in environment instead.
.Pp
This directive is useful for setting kernel tunables in
embedded environments that do not start from
.Xr loader 8 .
.\" HINTS
.It Cm hints Ar filename
Specifies a file to load a static device configuration specification
from.
From
.Fx 5.0
onwards, the kernel picks up the device configuration at boot time
(see
.Xr device.hints 5 Ns ).
This directive configures the kernel to use the static device configura