oasis

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oasis is a small linux system.

It is probably quite a bit different from other Linux-based operating systems you might be familiar with, and is closer to to a BSD.

There are many features that distinguish it from other operating systems:

• Completely statically linked.

All software in the base system is linked statically, including the display server (velox) and web browser (netsurf). Compared to dynamic linking, this is a simpler mechanism which eliminates problems with upgrading libraries, and results in completely self-contained binaries that can easily be copied to other systems.

• Fast builds that are 100% reproducible.

All packages are built with samurai, using build manifests generated by Lua scripts. This involves considerable up-front packaging cost, but minimal maintenance cost, and offers numerous advantages, including near optimal build times, predictable and reproducible builds, reduced build-time dependencies, and incremental builds even across package boundaries.

• Minimal bootstrap dependencies.

Any POSIX system with git, lua, curl, a sha256 utility, standard compression utilities, and an x86_64-linux-musl cross compiler can be used to bootstrap oasis. This makes it trivial to cross-compile, even from non-Linux systems such as macOS or OpenBSD.

• BearSSL is the system TLS and crypto library.

BearSSL is incredibly small and well written, but is not widely adopted. Through the use of libcurl, which now has native BearSSL support, and libtls-bearssl, an alternative implementation of libtls based on BearSSL, oasis uses BearSSL throughout the system. Only a few optional packages still require LibreSSL.

• No package manager.

Instead, you configure a set of specifications of what files from which packages to include on your system, and the build system writes the resulting filesystem tree into a git repository. This can then be merged into /, or pulled from another machine.

• Integrates well with OS-agnostic package systems.

Although the aim is to provide a complete system, there is a lot of free software out there, a lot of which does not match up well to our goals. Rather than trying to build and maintain yet another repository with thousands of packages, oasis works well with pkgsrc and nix. This makes it easy to extend your system with software you might need, while keeping the base system small and focused.

• Extremely simple system configuration.

A guiding principle is that the /etc directory should be simple enough for system administrators to understand completely and customize appropriately. The most complex file in the default configuration is the system initialization script, /etc/rc.init, at only 16 lines.

• Mostly ISO C conformant.

A major goal of oasis is to build with cproc, a C compiler which is much stricter about the ISO C standard than gcc or clang, and orders of magnitude smaller. Although this is a work-in-progress effort, all core packages, and most others, build successfully with cproc.

Principles

• Software complexity should be measured by including all transitive dependencies.
• Executables should be linked statically.
• Software components should allow for easy customization and/or modification.
• Package sources should be referenced through a URL or git submodule, but not included directly.
• /etc should be simple enough to be understood in its entirety.
• Patches should be well organized, have good descriptions, and should always apply cleanly.

Install

An install guide can be found on the wiki.

However, keep in mind that oasis is an ambitious project, and there is still a lot of work to do. Users should be comfortable building their own kernel and tinkering with their system when things go wrong. If you do run into trouble, I'm always happy to help you out.

QEMU

If you'd like to give oasis a try without installing it yourself, there is a QEMU image available here.

Inside the archive are the root filesystem, a Linux kernel, and a script to launch qemu. There is also README.md with some information about how to use it. In short, use ./run to launch in graphical mode, and ./run -s to launch in serial mode.

Software

oasis uses smaller and simpler implementations of libraries and tools whenever possible:

• musl instead of glibc
• sbase instead of coreutils
• ubase instead of util-linux
• pigz instead of gzip
• mandoc instead of man-db
• bearssl instead of openssl
• oksh instead of bash
• sdhcp instead of dhclient or dhcpcd
• vis instead of vim or emacs
• byacc instead of bison
• perp and sinit instead of sysvinit or systemd
• netsurf instead of chromium or firefox
• samurai instead of ninja
• velox instead of Xorg
• netbsd-curses instead of ncurses

These packages are grouped into logical sets, and the full list is available in the pkg directory.

If your favorite software is missing, keep in mind that you can likely still install it via pkgsrc or nix.

Contact

There is a mailing list at ~mcf/oasis@lists.sr.ht, and an IRC channel at #oasis on libera.chat. Feel free to use them for questions, patches, or general discussion.