Cross-compiling to Redox using Nix

By Aaron Janse on
Cross-compiling a package to Redox using Nix


Nixpkgs recently merged PR #93568, allowing the Nix package manager to cross-compile packages to Redox.

As expected, few of Nixpkgs’s 60,000 packages cross-compile to Redox without failing. I’ve created redoxpkgs, a wrapper around Nixpkgs to fix broken packages, with the hope that some patches will eventually be adapted upstream.

Nix has several properties that make cross-compiling to Redox pleasant. First, Nix reproducibly compiles packages, meaning that if a build works on my system, it should work on yours, too. Second, Nix allows porting packages en mass. A single change to a toolchain package could make a large number of packages suddenly compatible with Redox. Or, if needed, a patch could be automatically applied to the build process of every package of a given language being cross-compiled to Redox.

To get started, after installing Nix, simply checkout the Redox overlay (linked above) then run nix-build, specifying which package you want to cross-compile:

$ git clone
$ cd redoxpkgs
$ nix-build . -A hexyl

At the time of writing, few packages have been ported, but I hope to change that over time.

I plan to eventually setup a small Nix package cache for Redox. In the meantime, expect your first build to take a long time as Nix builds the Redox toolchain from source.

Going Forward

The future of Nix and Redox depends mostly on reception by the respective communities and how well the two systems work together long-term. It would be cool to port Nix to run on Redox itself so that packages can be built and installed on Redox rather than cross-compiled then copied from a Linux machine.

In theory, if enough packages are ported, the Redox ISOs themselves could be declaratively compiled using Nix. In the meantime, though, I plan to focus my efforts elsewhere, dogfooding my Nix toolchain as I continue to contribute to Redox.