Writing an OS in Rust (Second Edition)

Philipp Oppermann's blog

Building on Android

I finally managed to get blog_os building on my Android phone using termux. This post explains the necessary steps to set it up.

Screenshot of the compilation output from android

🔗 Install Termux and Nightly Rust

First, install termux from the Google Play Store or from F-Droid. After installing, open it and perform the following steps:

Now rustc --version should work and output a nightly version number.

🔗 Install Git and Clone blog_os

We need something to compile, so let's download the blog_os repository:

If you want to clone/push via SSH, you need to install the openssh package: pkg install openssh.

🔗 Install Xbuild and Bootimage

Now we're ready to install cargo xbuild and bootimage

Now cargo xbuild and bootimage should be available. It does not work yet because cargo xbuild needs access to the rust source code. By default it tries to use rustup for this, but we have no rustup support so we need a different way.

🔗 Providing the Rust Source Code

The Rust source code corresponding to our installed nightly is available in the its-pointless repository:

Now cargo-xbuild should no longer complain about a missing rust-src component. However it will throw an I/O error after building the sysroot. The problem is that the downloaded Rust source code has a different structure than the source provided by rustup. We can fix this by adding a symbolic link:

ln -s ~/../usr/opt/rust-nightly/bin ~/../usr/opt/rust-nightly/lib/rustlib/aarch64-linux-android/bin

Now cargo xbuild --target x86_64-blog_os.json and bootimage build should both work!

I couldn't get QEMU to run yet, so you won't be able to run your kernel. If you manage to get it working, please tell me :).