Operating Systems Lab (ECE NTUA 7th semester)

Students Involved: Kokoromytis Georgios, Konstantinos Fratzeskos

This repository collects coursework and exercise material for the Operating Systems laboratory, in ECE School of NTUA. The projects focus on core kernel-space concepts: Linux character device drivers, line disciplines, filesystem internals, synchronization, blocking I/O, and low-level process or memory behavior.

Repository Structure

Path	Topic	Description
lunix-tng/README.md	Character device driver	Implementation of the userspace-facing part of the Lunix:TNG wireless sensor network driver
fs/README.md	Filesystem	ext2-lite Linux kernel filesystem module based on a reduced ext2 design
riddle/README.md	CTF-like puzzles	Helper programs, notes, and artifacts for a binary exploitation / systems-behavior challenge named riddle

What Is Implemented Here

• lunix-tng/ contains a kernel module build for the 2024 Lunix:TNG lab, with the student work centered on the character device layer (open, read, release logic, cached formatting, blocking reads, and device registration)
• fs/ contains an ext2-lite filesystem module with the usual ext2-style split across superblock, inode, allocation, directory, and pathname handling code
• riddle/ contains small standalone C utilities and scripts used to satisfy individual challenge conditions of the provided riddle binary

Notes

• These projects were run on a custom VM - Utopia - built on QEMU-KVM, provided by CSLab NTUA. The kernel version used for development was Linux 6.11.
• Some workflows require root privileges because they load kernel modules, create device nodes, or mount filesystems
• The repository also contains generated binaries and run artifacts inside riddle/; they are part of the working history rather than core source code