CONFIG(8) | System Manager's Manual | CONFIG(8) |
config
— build
system configuration files
config |
[-CVgp ] [-I
path] [-d
destdir] SYSTEM_NAME |
config |
[-x kernel] |
The config
utility builds a set of system
configuration files from the file SYSTEM_NAME which
describes the system to configure. A second file tells
config
what files are needed to generate a system
and can be augmented by configuration specific set of files that give
alternate files for a specific machine (see the
FILES section below).
Available options and operands:
-V
config
version number.-C
-I
pathinclude
directive. This option may be specified
more than once.-d
destdirconfig
does not append
SYSTEM_NAME to the directory given.-m
-g
-x
kerneloptions INCLUDE_CONFIG_FILE
entry was present in your configuration file.-p
-p
options are supplied, config
configures a system
for high resolution profiling.The config
utility should be run from the
conf subdirectory of the system source (usually
/sys/ARCH/conf),
where ARCH represents one of the architectures
supported by FreeBSD. The
config
utility creates the directory
../compile/SYSTEM_NAME or the
one given with the -d
option as necessary and places
all output files there. The output of config
consists of a number of files; for the i386, they are:
Makefile, used by make(1) in
building the system; header files, definitions of the number of various
devices that will be compiled into the system.
After running config
, it is necessary to
run “make depend
” in the directory
where the new makefile was created. The config
utility prints a reminder of this when it completes.
If any other error messages are produced by
config
, the problems in the configuration file
should be corrected and config
should be run again.
Attempts to compile a system that had configuration errors are likely to
fail.
Traditional BSD kernels are compiled without symbols due to the heavy load on the system when compiling a “debug” kernel. A debug kernel contains complete symbols for all the source files, and enables an experienced kernel programmer to analyse the cause of a problem. The debuggers available prior to 4.4BSD-Lite were able to find some information from a normal kernel; gdb(1) provides very little support for normal kernels, and a debug kernel is needed for any meaningful analysis.
For reasons of history, time and space, building a debug kernel is
not the default with FreeBSD: a debug kernel takes
up to 30% longer to build and requires about 30 MB of disk storage in the
build directory, compared to about 6 MB for a non-debug kernel. A debug
kernel is about 11 MB in size, compared to about 2 MB for a non-debug
kernel. This space is used both in the root file system and at run time in
memory. Use the -g
option to build a debug kernel.
With this option, config
causes two kernel files to
be built in the kernel build directory:
There is currently little sense in installing and booting from a debug kernel, since the only tools available which use the symbols do not run on-line. There are therefore two options for installing a debug kernel:
make install
” installs
kernel in the root file system.make install.debug
” installs
kernel.debug in the root file system.The SYNOPSIS portion of each device in section 4.
Building 4.3 BSD UNIX System with Config.
The config
utility appeared in
4.1BSD.
Before support for -x
was introduced,
options INCLUDE_CONFIG_FILE
included entire
configuration file that used to be embedded in the new kernel. This meant
that strings(1) could be used to extract it from a kernel:
to extract the configuration information, you had to use the command:
strings -n 3 kernel | sed -n
's/^___//p'
The line numbers reported in error messages are usually off by one.
May 8, 2007 | Debian |