link: allow retrieving perf event file descriptor

[lmb]

link: allow retrieving perf event file descriptor

Tetragon needs access to the underlying perf event file descriptor to
perform black magic on older kernels. Expose this via an additional
PerfEvent interface that users can assert.

Signed-off-by: Lorenz Bauer <lmb@isovalent.com>

[lmb]

Use would be something like:

kp, _ := Kprobe()

if pe, ok := kp.(link.PerfEvent); ok {
   file, err := pe.PerfEvent()
}

// Same for Uprobe

• Naming of the method isn't great :(
• I'll document this in the exported callers of attachPerfEvent, but still hard to discover. Probably OK since this is a power user thing anyways?

[olsajiri]

using it in here cilium/tetragon@9098f1e , seems to work nicely, thanks

[olsajiri]

great, thanks a lot!