Coding Conventions

Developer Certificate of Origin (DCO)

The seL4 Foundation does not require any contributor license agreements or other documents for contributions. It uses the same sign-off process as the Linux kernel, the so-called Developer Certificate of Origin.

Signing off on commits

For every commit, use

git commit -s

to add a sign-off line to your commit message, which should come out as:

Signed-off-by: name <email>

Use a real, contactable email address. Using a real name is appreciated, but pseudonyms are permitted.

By adding this line, you make the declaration that you have the right to make this contribution under the open source license the files use that you changed or contributed.

Generally, you usually have this right when you wrote the contribution yourself and your employer allows you to make open-source contributions. You do not always need to be the original author of the code, for instance making a contribution to GPL code by copying and modifying other GPL code can be perfectly fine. You can also sign off on somebody else’s behalf.

The full text of the declaration is at https://developercertificate.org.

The seL4 GitHub repositories are configured to only accept pull requests where all commits are signed off. There are no other signatures or legal documents required.

Some tips on using signed-off-by with git:

  • signed-off-by is different from signing commits with a GPG key (commit -S)
  • you can use git commit --amend -s to sign off a single existing commit if you’ve forgotten
  • you can use git rebase --signoff <base-branch> for signing off multiple commits on a whole branch
  • the DCO allows you to sign off commits for others – see https://developercertificate.org for details

  • you can add an alias for sign-off to your git config, so you don’t have to think about it. For instance:

          git config alias.ci “commit -s"

    Now git ci will commit with sign-off. The config command above is local for the current repository.