seL4 Website

The seL4.systems website is built with the static site generator Jekyll, which uses the Liquid templating engine.

Tool Dependencies

Ruby

Installing rbenv

We recommend using rbenv to install the correct Ruby version.

On Mac, using homebrew:

brew install ruby-build rbenv

On apt-based Linux distributions (e.g. Ubuntu, Debian):

apt install rbenv

Setting up rbenv

# follow the instructions this command shows, and start a new shell afterwards
rbenv init
# in the docs directory (root of this repo):
rbenv install

After these, you should be able to forget about rbenv, the Makefile will now see the correct Ruby version.

Node and Tailwind

The site uses Tailwind CSS, which requires node. Any node version >= 20 should work, the automated build is using the latest patch release of version 22.

You can install node on via brew install node or apt install node depending on your OS. If your OS comes with a too-old version of node pre-installed, we recommend using the node version manager nvm. Its README has a one-touch install script.

Once nvm is installed, you can get the correct node version by running nvm install in the root directory of this repository.

HTML5 validator (optional)

To manually run the html5validator script via make validate, you need to install

pip install --user html5validator

The validator also needs a working Java runtime installation, which you can get from https://java.com or via your package manager.

Build

Running make build will generate the pages and put them into the _site/ directory. To preview the website locally, run

make serve

for the production build and make debug for the development build. See make help for all options.

There are two variants of the website to build. When running on seL4 the site includes an additional footer with a link to pages describing the setup. To build this variant, use

make on_seL4

The site will be generated into _site_on_seL4/.

Making Changes

Contributions are welcome — if you find anything out of date, any typos or inaccuracies, please raise a pull request on this repository.

Links

For the preview functionality on pull requests to work, all links to internal pages and images need to be relative to the file they are made from. That means, please do not use links that start with a / such as /Foundation/page.html even though Jekyll encourages that.

There are two ways to use relative links: either directly use the relative path (usually nicer), or use the relative_url function in Jekyll/Liquid.

Examples:

<a href="../Foundation/a-page.html">
<img src="../images/something.jpg">

With relative_url:

<a href="{{ '/Foundation/a-page.html' | relative_url }}">

Note: relative_url only produces a site-relative URL not a path-relative URL, but Jekyll has enough setup to prepend the correct prefix for the GitHub previews to work, so it is fine to use.

link tags in the front matter of pages are automatically used with relative_url, so it is fine to use absolute links there.

News items can potentially get included from multiple pages. Always use relative_url in those.

Licences

Files in this repository (with a few exceptions) are released under standard open source licences, identified by SPDX Licence tags. See individual file headers for details.

As a general rule, new code files should be under BSD-2-Clause, and documents under the [Creative Commons Licence CC-BY-SA 4.0 International licence in this repository.

Some files contain representations of trademarks. Irrespective of any licence markings, logos and trademarks in this repository are owned by their respective owners. No licenses or other rights in or to such logos and/or trademarks are granted. The Trademark guidelines for the seL4 Foundation can be found at https://sel4.systems/Legal/trademark.html

Permission to use pictures of people have been granted for display on the seL4.systems website only. Please do not use them for any other purpose.