In its second synopsis form,
config
takes the binary kernel
kernel-file
as its single argument (aside from the mandatory
-x
flag), then extracts the embedded configuration file (if any) and
writes it to standard output.
If
kernel-file
is not given,
/netbsd
is used.
Configuration data will be available if the given kernel was compiled
with either
INCLUDE_CONFIG_FILE
or
INCLUDE_JUST_CONFIG
options.
In its third synopsis form, config is a tool for the kernel developer and generates a ``lint'' configuration file to be used during regression testing. Refer to section LINT CONFIGURATION for the details of that use of .
config accepts the following parameters:
There are several different ways to run the
config
program.
The traditional way is to run
config
from the
conf
subdirectory of the machine-specific directory of the system source
(usually
/sys/arch/MACHINE/conf
,
where
MACHINE
is one of
vax
,
hp300
,
and so forth), and to specify as the
config-file
the name of a machine description file located in that directory.
config
will by default create files in the directory
../compile/SYSTEMNAME
,
where
SYSTEMNAME
is the last path component of
config-file.
config
will assume that the top-level kernel source directory is located four
directories above the build directory.
Another way is to create the build directory yourself, place the
machine description file in the build directory with the name
CONFIG
,
and run
config
from within the build directory without specifying a
config-file.
config
will then by default create files in the current directory.
If you run
config
this way, you must specify the location of the top-level kernel source
directory using the
-s
option or by using the
``source
''
directive at the beginning of the machine description file.
Finally, you can specify the build directory for
config
and run it from anywhere.
You can specify a build directory with the
-b
option or by using the
``build
''
directive at the beginning of the machine description file.
You must specify the location of the top-level kernel source directory if you
specify a build directory.
If config-file is a binary kernel, config will try to extract the configuration file embedded into it, which will be present if that kernel was built either with INCLUDE_CONFIG_FILE or INCLUDE_JUST_CONFIG options. This work mode requires you to manually specify a build directory with the -b option, which implies the need to provide a source tree too.
If the
-p
option is supplied,
.PROF
is appended to the default compilation directory name, and
config
acts as if the lines
``makeoptions
PROF="-pg"
''
and
``options
GPROF
''
appeared in the machine description file.
This will build a system that includes profiling code; see
kgmon(8)
and
gprof(1).
The
-p
flag is expected to be used for
``one-shot''
profiles of existing systems; for regular profiling, it is probably
wiser to create a separate machine description file containing the
makeoptions
line.
The old undocumented
-g
flag is no longer supported.
Instead, use
``makeoptions
DEBUG="-g"
''
and (typically)
``options
KGDB
''.
The output of
config
consists of a number of files, principally
ioconf.c
,
a description of I/O devices that may be attached to the system; and a
Makefile
,
used by
make(1)
in building the kernel.
After running
,
it is wise to run
``make
depend
''
in the directory where the new makefile
was created.
config
prints a reminder of this when it completes.
If config stops due to errors, the problems reported should be corrected and config should be run again. config attempts to avoid changing the compilation directory if there are configuration errors, but this code is not well-tested, and some problems (such as running out of disk space) are unrecoverable.
When used with the -L flag, config takes the regular configuration file config-file and prints on the standard output a configuration file that includes config-file, selects all options and file-systems the user can possibly select, and defines an instance of every possible attachment as described by the kernel option definition files used by config-file.
The resulting configuration file is meant as a way to select all possible features in order to test that each of them compiles. It is not meant to result in a kernel binary that can run on any hardware.
Unlike the first synopsis form, the provided srcdir is relative to the current working directory. In the first synopsis form, it is relative to the build directory.