GenesisOS

Dumb project I made because I wanted to learn about kernels and how they work. You are welcomed to contribute to my chaos and join the cult.

This operating system have the following features:

• Kernel allocator
• Virtual Memory
• Interrupts / IRQs
• Disk: ATA PIO
• Syscalls
• Scheduler (Round-Robin algorithm)
• Console/UART driver
• Filesystem: Support FAT32
• ELF Loader
• Userland shell/init binary
• Devices/File descriptors(not rly/partial)

All this work, just to load an ELF binary that echoes back whatever you write to it by calling SYS_read and SYS_write:

To write this project, I used:

• Intel SDM Vol 3(325384-sdm-vol-3abcd.pdf)
• OSDev Discord community(link)
• OSDev: https://wiki.osdev.org/
• "The little book about OS development": https://littleosbook.github.io/
• Academic projects: SerenityOS, JOS and xv6 (to get inspiration for design ideas)
• nanobyte-dev YT channel to get introduction on FAT filesystems.

Build & Run

Launch an ubuntu:20.04 container and follow the steps below

docker run -v $(pwd):/share/ --rm --privileged --name osdev -it ubuntu:20.04

1. First, run ./deps-container.sh to install the required dependencies.
2. prepare the directory tree by running make dirsetup
3. Compile & pack everything by running make iso
4. To run the OS in qemu, run make qemu-nox

Note: nox stands for no-graphics. If you run make qemu a qemu window will pop. However, it has bugs because the video driver is not finished(unlike the UART/console driver, which is more mature)

Debug

To debug:

1. Run make qemu-gdb
2. Connect with gdb by running target remote :12345

Security

Found a security issue? Good, fix it and send a PR.

There are plenty of vulns around the codebase. I'm considering opening a special activities/event for vuln researchers who are interested in OSDev so we can learn and grow together. Should update about it in the Discord server.

Compile DB

For easier code navigation and auto-completion, use clangd's vscode plugin + compiledb.

compiledb make iso