debuginfod support for fetching debuginfo on the fly

[fche]

https://github.com/pixie-labs/pixie/blob/d9edd5d86db11964c1f00137e691be332cb169d4/src/stirling/obj_tools/elf_tools.cc#L94

The debuginfod protocol/service is a way of letting tools like pixie download dwarf debuginfo on the fly, based on a build-id, from an HTTP server. The elfutils library provides a client side library or command-line tool, or one can make an HTTP request directly. Several distros run servers, and people can run their own.

https://sourceware.org/elfutils/Debuginfod.html

[yzhao1012]

Pixie uses https://github.com/iovisor/bcc and https://github.com/iovisor/bpftrace.
Both bcc & bpftrace already uses debuginfod: iovisor/bpftrace#1774

Pixie itself also uses dwarf info outside of bcc & bpftrace. For example, Pixie uses dwarf info to generate BCC C code for https://docs.px.dev/tutorials/custom-data/dynamic-go-logging/.

We are investigating rupran/bcc@3f446c4, and see how to make similar changes to dynamic-go-logging to utilize debuginfod client.

[yzhao1012]

@fche Could you provide an instruction of how to install debuginfod on ubuntu? I could not fine such instructions.
Also an instruction for build and run debuginfod from source is also needed for experimentation, as we might need to build docker image of debuginfod to use it on kubernetes cluster.

[fche]

https://packages.ubuntu.com/search?searchon=sourcenames&keywords=elfutils
versions >0.179 include debuginfod client & server code.

Building from source is the usual autoreconf; configure; make all install.