Enabling the upstream Rust toolchain

August 24 2023 by Benjamin Lamowski

Release 23.05 reintroduced support for the Rust programming language to Genode, but our initial implementation relied on a slightly adapted Rust toolchain. As detailed in my previous blog post, we were working around issues with versioned FreeBSD libc symbols that were unsupported by our linker.

With release 23.08, we have overcome this limitation. My colleague Sebastian Sumpf implemented a compatibility library and we managed to minimize runtime impact by injecting it as a static library into the rustc linker invocation.

Slightly simpler instructions to get started

On x86_64 Linux, first install Rust's rustup toolchain manager by a method of your choosing and proceed to install the upstream x86_64-unknown-freebsd target:

 $ rustup toolchain install stable-x86_64-unknown-linux-gnu
 $ rustup target add x86_64-unknown-freebsd

Until we provide new pre-built Genode packages with the upcoming Sculpt release, you still need to build the required runtime packages. For this, install Genode's toolchain and follow the Getting started instructions to get a working Genode build environment. Once you have a working development environment at path/to/genode, locally build the required packages:

 $ cd path/to/genode
 path/to/genode $ ./tool/depot/create FORCE=1 REBUILD= UPDATE_VERSIONS=1 \
                  genodelabs/bin/x86_64/vfs genodelabs/bin/x86_64/posix  \
                  genodelabs/bin/x86_64/init genodelabs/bin/x86_64/libc  \
                  genodelabs/bin/x86_64/base-linux \
                  genodelabs/api/compat-libc

You should now be able to build our example Rust application with Goa using the upstream Rust toolchain:

 $ git clone https://github.com/genodelabs/goa
 $ cd goa
 goa $ export PATH="$PATH:$(pwd)/bin"
 goa $ goa run -C examples/hello_rust --versions-from-genode-dir path/to/genode \
                                      --depot-dir path/to/genode/depot

As a little test of the versioned C library calls, this should print:

 [init -> hello_rust] Hello Genode Rust world!
 [init -> hello_rust] FileType(FileType { mode: 32896 })
 [init -> hello_rust] inode: 1

In the publishing pipeline: a real Rust package

We have a port of the popular ripgrep search tool running on Genode. While building a Goa package was a pleasant, straightforward experience, the build was pushing the boundaries of our FreeBSD libc backend. This is to be expected: we extend our support of the FreeBSD or Posix API incrementally as needed. Although the extension of our libc backend went smoothly, we decided to give it some more testing and publish our ripgrep package at the next Sculpt OS release, when the supporting packages are available at depot.genode.org.