Introduce Signal API

[krisnova]

Can we please add an API to expose POSIX signals metadata using Aurae?

This will be helpful for a few reasons, notably:

• It gives us a reason to "plumb" an eBPF loader/unloader framework into Aurae.
• It gives us the ability to offer observability remotely on POSIX signals

[krisnova]

See the signals-ebpf probe for more context: https://github.com/ricardomaraschini/ebpf-signals

[JeroenSoeters]

Is this something we would want to add to the Observe API?

[dmah42]

yes

[JeroenSoeters]

Looking at: https://github.com/ricardomaraschini/ebpf-signals/blob/main/signals-ebpf/src/main.rs#L15 and wondering why I never noticed those format files before 😭 This means - at least for this first cut - we don't need to rely on BTF symbols to be available on the host? We would require debugfs to be mounted, though.

(assuming here we want to ship pre-compiled eBPF programs)

[JeroenSoeters]

Should we close this one?