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Sigil is an experimental operating system distribution built on the Genode OS framework, the Nix package manager, and the NixOS modular configuration system.

Sigil was initially financed by NLnet and the Privacy and Trust Enhancing technologies (PET) fund under the name "Genodepkgs". The project halted in early 2021 due to overwhelming technical challenges but is still intermittently updated.

While it is unlikely that Sigil will ever manifest a viable OS, it does serve as a testing ground for post-UNIX packaging and system distribution concepts. It also serves as an extreme test case for Nixpkgs cross-compilation and portability.

Articles

• Deferred linking in Sigil
• Genodepkgs post-mortem report

Repository layout

• Native packages are at packages

• Existing Nixpkgs packages are patched at overlay

• Tests are at tests

• NixOS modules at nixos-modules

Packaging

Packaging is done using standard Nixpkgs methods, a stdenv is available for cross-compilation. See Solo5 as an example.

Cross-compiling Nixpkgs

Some existing packages from Nixpkgs can be built with little or no modification. Nixpkgs is available at the path .#legacyPackages.x86_64-linux-x86_64-genode (or …-aarch64-genode) and modifications to packages are made at an overlay. Some packages need patched, others require additional features added to the Genode libc.

Packages that run on Linux as well as Genode should not be packaged here, those should be added to Nixpkgs.

Toolchain

The Genode Labs toolchain is available here only for Linux and in binary form. However, an experimental LLVM cross-compiler is provided here. Bootstrapping GCC has not been practical due to its recursive autotools build system.

The enter a shell with the toolchain:

nix shell .#legacyPackages.x86_64-linux-x86_64-genode.stdenv.cc

x86_64-unknown-genode-clang++ -v

Tips and tricks

Binary cache

Binaries and other artifacts are available from Cachix.

cachix use sigil

How to add missing Genode ports to a Genode depot package?

The missing ports as indicated by a depot build failure must be added to targets.nix. For example:

{
  wifi_drv = {
    depotInputs = with self; [ libcrypto ];
    portInputs = with ports; [ dde_linux ];
  };
}

How to add undefined ports?

Should a required port not be defined, it must be added to ports.nix. Initially it should be sufficient to define the port as an empty attribute set, run the build again, and then add the hash found in the successive build error.

To continue from the previous example:

{
  dde_linux = { };
}

And after the reattempting the build a fixed-output hash should be produced, this must now be added to the port definitions.

{
  dde_linux = {
    hash = "sha256-3G5Mprv9ZBNhDJRuVF6Nrkp3KbFaN10IKFq0OdyAY9M="; };
}

Should the port preparation fail do to missing utilities, these must be added to the port definition using a nativeBuildInputs attribute.

Note that the hash checked into ports.nix is an output hash. The port hash within the Genode source tree is an explicit input hash.

Building a package from a test

nix build -L .#checks.x86_64-linux.«TEST_NAME».nodes.machine.config.genode.init.children.«CHILD_NAME».package

A binary is loading ERIS URNs, where do the URNs come from?

nix run .#readelferislinks result/bin/*

Pronunciation

Legal

This repository is published under MIT licensing consistent with Nixpkgs.

Note: MIT license does not apply to the packages built by Nixpkgs, merely to the files in this repository (the Nix expressions, build scripts, NixOS modules, etc.). It also might not apply to patches included in Nixpkgs, which may be derivative works of the packages to which they apply. The aforementioned artifacts are all covered by the licenses of the respective packages.

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