"os" (proper name pending)

An x86-64 µkernel in Assembly. User-space parts in Assembly and C.

License

This software is licensed under the MIT license. See the LICENSE file.

Building the cross-toolchain

Scripts for building a cross compiler can be found in toolchain/. Running ./build.sh in that directory will download the tarballs (if necessary), verify the signatures, unpack, configure and build.

Cross-compiling grub

On Linux systems, using the system grub is usually fine, but to support more esoteric operating systems (e.g. macOS), grub needs to be cross-compiled with an ELF toolchain. Use the ./build.sh script in grub/ to build one after building the toolchain.

grub-mkrescue also requires xorriso.

Building

After building the cross-compiler and cross-grub, just run make to build the kernel(s) and user-space components. ccache is used by default, but can be disabled by setting CCACHE= on the Make command line. (Just install ccache though. Srsly.)

Network setup

User-mode networking

The simplest setup and the default in run_qemu.sh. QEMU presents a virtual network with an internal DHCP server and something similar to NAT. Port 5555 on localhost is redirected to port 80 on the virtual machine, which is where the lwIP web server is listening.

Setting up tun/tap networking

Useful when working on low-level network stuff, since it allows easy wiresharking of all traffic over the simulated network, and makes the VM available to all the normal network debugging tools (arping, ping, etc).

To create a tun/tap device owned by yourself,

Install uml-utilities (for tunctl),
run sudo tunctl -u $(whoami), this will print the name of the created device, which should be tap0 (which is hardcoded in various places)
then sudo ifconfig tap0 up 192.168.100.1 to set the IP
modify the lwIP program for a static IP
modify run_qemu.sh or bochsrc to use the tun/tap networking

The lwIP program needs to be modified to set up a static IP at 192.168.100.3, but after that it should present the dumb web server on that IP.

Running in QEMU

To run in qemu, there's a wrapper script in ./run_qemu.sh that automatically runs make and starts qemu.

Running in Bochs

See notes/bochs.txt for build instructions for bochs 2.6.

Build everything as above, then start bochs using bochs from the repo root. A .bochsrc with most of the necessary settings is provided.

Known issues

Only unknown issues left. Yay!

olsner/os