CONFIG(8)

NAME
config - build kernel compilation directories

SYNOPSIS
config [-b builddir] [-s srcdir] [-p] [config-file]

DESCRIPTION
config creates a kernel build directory from the file config-file, which describes the system to configure.

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, tahoe, hp300, and so forth), and to specify as the config-file the name of a 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 configuration 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 system configuration 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 system configuration file. You must specify the location of the top-level kernel source directory if you specify a build directory.

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 configuration 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 make a separate configuration 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.

SEE ALSO
The SYNOPSIS portion of each device in section 4. Building 4.4 BSD Systems with Config.

options(4)

HISTORY
The config command appeared in 4.1BSD. It was completely revised in 4.4BSD.