CONFIG(8)

NAME
config - build system configuration files

SYNOPSIS
config [-gr] [-d destdir] SYSTEM_NAME

DESCRIPTION
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:

-d destdir
    Use destdir as the output directory, instead of the default one. Note that config does not append SYSTEM_NAME to the directory given.

-g  Configure a system for debugging.

-r  Remove the old compile directory (see below).

SYSTEM_NAME
    Specify the name of the system configuration file containing device specifications, configuration options and other system parameters for one system configuration.

config should be run from the config subdirectory of the system source (usually /sys/config). config creates the directory ../compile/SYSTEM_NAME or the one given with the -d option as necessary and places all output files there. If the output directory already exists and the -r flag was specified, it will be removed first. The output of config consists of a number of files; for the x86_64 architecture, they are: ioconf.c, a description of what I/O devices are attached to the system; 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.

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.

If the options INCLUDE_CONFIG_FILE is used in the configuration file the entire input file is embedded in the new kernel. This means that strings(1) can be used to extract it from a kernel: to extract the configuration information, use the command

    strings -n 3 kernel | sed -n 's/^___//p'

DEBUG KERNELS
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; kgdb(1) provides very little support for normal kernels, and a debug kernel is needed for any meaningful analysis.

In order to ease posting bug reports for inexperienced users and make the debugging environment more uniform, DragonFly installs kernel and modules unstripped. Debug information is not loaded into memory, so the only impact is the extra space consumption. Those wishing to install stripped down kernel and modules can specify two new make options in their kernel config file or when they run the kernel-related targets to make:

INSTALLSTRIPPED=1
    The installed kernel and modules will be stripped of debug info.

INSTALLSTRIPPEDMODULES=1
    The installed modules will be stripped of debug info. The kernel will be left with debug info intact.

Backup copies of the kernel and modules are automatically stripped of their debug information by objcopy(1), unless NO_KERNEL_OLD_STRIP is set in make.conf(5).

FILES

/sys/conf/files
    list of common files system is built from

/sys/config/SYSTEM_NAME
    default location for kernel configuration file

/sys/config/LINT64
    kernel configuration file for checking all the sources, includes description of kernel configuration options

/sys/config/VKERNEL64
    default 64 bit vkernel(7) kernel configuration file

/sys/config/X86_64_GENERIC
    default x86_64 kernel configuration file

/sys/compile/SYSTEM_NAME
    default kernel build directory for system SYSTEM_NAME

/sys/platform/PLATFORM/conf/Makefile
    generic makefile for the PLATFORM

/sys/platform/PLATFORM/conf/files
    list of PLATFORM specific files

SEE ALSO
gprof(1), kgdb(1), make(1), kernconf(5), build(7), vkernel(7)

The SYNOPSIS portion of each device in section 4. Building 4.3 BSD UNIX System with Config.

HISTORY
The config utility appeared in 4.1BSD.

BUGS
The line numbers reported in error messages are usually off by one.