KarLS

KarLS / Karl's absolutely reduced Linux System

KarLS is an experimental busybox/musl based mini distro, built completely from sources. It is currently tested on KVM/QEMU - including Google Compute Engine - and VMware. Also tested and works on Asus' excellent but EOL Chromebook C302C(A) - after unlocking UEFI and scrubbing chromeos ofc. See doc/ for more info. It supports only x86_64, and raspberry pi support is planned - I have previous experience with cross-compiling to the PI.

KarLS is a hobby thing, that started out like sort of a reproduciple Linux From Scratch. Buildroot also gave KarLS lots of inspiration of course, that's a great professional project. For any production project I highly recommend BR. Karls uses an own gcc/binutils/musl/ccache etc. toolchain, as BR does.

Warning

Currently, KarLS is aiming to reach minimal usability, a.k.a. 1.0. - still far away from there.

To compile natively (I build on Debian 12):

• make install_deps - apt install a few packages - uses sudo
• make cmpl - compile the musl based gcc compiler toolchain
• make pkg - compile the packages, then package them into .kpm format
• make iso - compile and build the installation iso image

To compile in a Docker container

Download the dockerfile from the docker-build subdirectory of this repo into an empty directory. No need to clone the whole git. Run docker build -t karls-builder . in the new subdirectory. I recommend running this in a detachable terminal like tmux, as it runs for a long time. This will setup a minimal Debian based container and run the whole build process. It will require around 16 GB. See docker-build/README.md for some more information.

Other useful commands:

/ main directory and /cmpl /pkg / iso subdirectories

• make status - view the status of the 3 subdirectories where building is done: cmpl, pkg and iso. This is done with tail -1 DIR/.status - the new .status file holds a simple build log.
• make download - download all required sources before doing anything (normally done right before the compilation of the program starts)
• make sha256sum - verify all sources with sha256sum (this is done everytime right after download, so this is a double-check option)
• make clean - delete compiled sources
• make distclean - delete compiled sources, patched sources\ and compiler cache (ccache)
• make mrproper - like distclean, but delete downloaded srouces too.
• make genpatch - generate patch file from patched source package $PPKG (in */src subdirectory), $PTCNAME is the name of ther patch, $PTCCOMMENT is the patch comment - see /common.mk

in cmpl/ subdirectory

• make reset_cmpl - delete compiler and extract it as a vanilla unomdified version since the last compalation - useful for testing package library dependecies

in pkg/ subdirectory

• make busybox-config - run make menuconfig in patched busybox source, make a diff file in pkg/busybox directory with config changes
• make kernel-config - run make menuconfig in patched kernel source, make a diff file in pkg/kernel directory with config changes

in iso/ subdirectory

• make rebuild_initrd - rebuild the initrd for the install iso, after changing kernel/modules, etc.
• make rebuild_iso - rebuild iso, after changing packages - initrd stays the same!
• make gcp_image - package the qemu installed disk image as a Google Compute Engine image, for uploading as a custom GCE image
• make qemu - start qemu with the installation iso in a virtual cdrom drive - works in / main directory too
• make ssh - ssh into the running qemu system after installation - works in / main directory too