Kconfiglib

A Python library for doing stuff with Kconfig-based configuration systems. Can extract information, query and set symbol values, and read and write .config files. Highly compatible with the scripts/kconfig/*conf utilities in the kernel, usually invoked via make targets such as menuconfig and defconfig.

Update: Mar 13 2015

Thanks to a patch from Philip Craig that adds support for the new allnoconfig_y option (which sets the user value of certain symbols to y during make allnoconfig to improve coverage) and fixes an obscure issue with comments inside choices (that didn't affect correctness but made outputs differ) the test suite now passes with Linux v4.0-rc3. Very little seems to have changed in the C implementation over the past years, which is nice. :)

One feature is missing: Kconfiglib assumes the modules symbol is MODULES, and will warn if option modules is set on some other symbol. Let me know if this is a problem for you, as adding support shouldn't be that hard. I haven't seen modules used outside the kernel, where the name is unlikely to change.

Installation

Installation instructions for the Linux kernel

Run the following commands in the kernel root:

$ git clone git://github.com/ulfalizer/Kconfiglib.git  
$ git am Kconfiglib/makefile.patch

(Note: The directory name Kconfiglib/ is significant.)

In addition to creating a handy interface, the make targets created by the patch (scriptconfig and iscripconfig) are needed to pick up environment variables set in the kernel makefiles and later referenced in the Kconfig files (ARCH, SRCARCH, and KERNELVERSION as of Linux v4.0-rc3). The documentation explains how the make targets are used. The compatibility tests in the test suite also needs them.

Please tell me if the patch does not apply. It should be trivial to apply manually.

Installation instructions for other projects

The entire library is contained in kconfiglib.py. Drop it somewhere and read the documentation. Make sure Kconfiglib sees environment variables referenced in the configuration.

Documentation

The (extensive) documentation is generated by running

$ pydoc kconfiglib

in the Kconfiglib/ directory. For HTML output, use

$ pydoc -w kconfiglib

You could also browse the docstrings directly in kconfiglib.py.

Please tell me if something is unclear to you or can be explained better. The Kconfig language has some dark corners.

Examples

The examples/ directory contains simple example scripts. See the documentation for how to run them.
gen-manual-lists.py from Buildroot generates listings for the appendix of the manual. Due to an oversight, there were no APIs for fetching prompts from symbols and choices when it was written. Those have been added.
genboardscfg.py from Das U-Boot generates some sort of legacy board database by pulling information from a newly added Kconfig-based configuration system (as far as I understand it :).
Originally, Kconfiglib was used in chapter 4 my master's thesis to automatically generate a "minimal" kernel for a given system. Parts of it bother me a bit now, but that's how it goes with old work.

Test suite

The test suite is run with

$ python Kconfiglib/testsuite.py

It comprises a set of selftests and a set of compatibility tests that compare configurations generated by Kconfiglib with configurations generated by scripts/kconfig/conf for a number of cases. You might want to use the "speedy" option; see testsuite.py.

Misc. notes

Python 2 is used at the moment.
Kconfiglib works well with PyPy. It might give a nice speedup over CPython when batch processing a large number of configurations, as well as when running the test suite.
Please tell me if you miss some API instead of digging into internals. The internal data structures and APIs, and dependency stuff in particular, are unlikely to be exactly what you want as a user (hence why they're internal :). Patches are welcome too of course. ;)
fpemud has put together Python bindings to internal functions in the C implementation. This is an alternative to Kconfiglib's all-Python approach.
The test suite failures (should be the only ones) for the following Blackfin defconfigs on e.g. Linux 3.7.0-rc8 are due to a bug in the C implementation:
- arch/blackfin/configs/CM-BF537U_defconfig
- arch/blackfin/configs/BF548-EZKIT_defconfig
- arch/blackfin/configs/BF527-EZKIT_defconfig
- arch/blackfin/configs/BF527-EZKIT-V2_defconfig
- arch/blackfin/configs/TCM-BF537_defconfig

License (ISC)

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

tSed/Kconfiglib