Nightingale

About

Nightingale is an operating system for x86_64 that I have been developing for 5 years to learn about low-level programming and operating system design.

Nightingale implements a mostly POSIX-like userland, though compliance is not a goal. I see POSIX as useful as a well-understood and documented interface, and one that permits compatability with large amounts of existing software.

For more specific feature and capability information, see ABOUT.md.

Project map

Directories

• doc: Documentation
• include: Header files for the whole system
• interface: Interface definitions for syscalls and errno values
• kernel: The core of the operating system
• libc: Common userland routines, including things like printf
• linker: Kernel module loader, userland dynamic linker, and libelf
• modules: Kernel modules, mostly testing for now
• script: Utility scripts for building and developing nightingale
• toolchain: Patches and staging area for hosted gcc toolchain
• user: In-tree usermode programs distributed with the system

Scripts

• build_toolchain.bash: builds the custom gcc for the x86_64-nightingale target
• dump.rb: convenience wrapper around objdump
• flamegraph.bash: convenience wrapper to call flamegraph - see ABOUT.md
• format.bash: convenience wrapper around the clang-format code formatter
• generate_syscalls.rb: render the syscall and errno manifests into C datastructures
• install_headers.bash: create sysroot and install system headers to the sysroot
• run.rb: convenience wrapper around qemu-system-x86_64 to set the options I need

Interface Manifests

These manifest files define the public syscall interface of the nightingale kernel, they are rendered into C enums and metadata that is used by both the kernel and the C library.

• ERRNOS: defines the values of errno, their names, and their perror strings
• SYSCALLS: defines syscall numbers, types, and arguments

Building nightingale

Nightingale uses the CMake build system and defaults to the clang compiler.

The only uncommon package you will need is the grub-mkrescue tool provided by grub2. This is usually packaged with grub2 or in a 'grub tools' package.

• Clang (default)
  • Execute make in the root of the project.
  • To run, use ./run.rb - its help text will show the available options Clang (default)
• GCC (extra programs only)
  • Inspect script/build_toolchain.bash to see the dependencies and edit the constants to match your environment (install directory, parallelism, etc)
  • Run script/build_toolchain.bash and ensure the resulting binaries are available on your PATH
    • x86_64-nightingale-gcc --version should show the GCC version if everything worked correctly.
    • As written, the script assumes you have ~/.local/bin on your PATH - you'll want to edit PREFIX and/or PATH to put it somewhere else.

I was able to build and run nightingale on a stock Ubuntu 20.04 image with the following commands:

$ apt update
$ apt install git make cmake clang llvm lld ninja-build ruby xorriso mtools qemu-system
$ git clone https://github.com/tyler569/nightingale.git
$ make
$ ./run.rb

Why 'nightingale'?

I have a long history of naming projects after birds, this is no exception.

Acknowledgements

I used many resources to learn what I needed to get to where I am, but a special shout-out goes to the OSDev Wiki community, for their extensive and comprehensive reference material that I have made extensive use of.

I've used code from several other people, lots of credit goes to lua, the Sortix project for their libm, Nicholas J. Kain for the original implementation of my setjmp, and Krzysztof Gabis for writing the brainf**k interpreter that was the first third-party software I ever ported to nightingale.