patch PR25722: /path/name based debuginfod-find & API lookups

[Mark Wielaard]

Hi Frank,

On Wed, 2020-03-25 at 21:39 -0400, Frank Ch. Eigler via Elfutils-devel wrote:
> commit b27d38f7eed6d99715fd1cc8a70b0a6a2b04f0ce (HEAD -> fche/pr25722)
> Author: Frank Ch. Eigler <fche@redhat.com>
> Date:   Wed Mar 25 21:36:51 2020 -0400
> 
>     PR25722: debuginfod client api: accept /path/names in place of buildid hex
>     
>     As a convenience, this extends the debuginfod find functions (and thus
>     debuginfod-find) to accept a /path/name to an ELF binary as an
>     alternative to a hexadecimal string for buildid.  Doc & testing incl.

I like the functionality for debuginfod-find, but think it is not
really appropriate for the debuginfod client API. It is a little hacky.
The user code has to know that it has to call elf_version () first. The
interface using path names is somewhat awkward since users probably
already have an file descriptor or ELF handle open for the file. It
adds a dependency on libelf and libdw for two convenience function
calls that the user could do themselves. And it only handles the main
build-id in the file, e.g. you cannot easily use it for fetching the
multi/alt-file.

I think we should move the functionality as is just into debuginfo-find 
and experiment a bit with it before adding it as a public API to the
debuginfod-client API.

In debuginfod-find the code would also be slightly simpler since it
doesn't have to convert to a hex-string first, it can just pass the
build-id bytes as is.

Cheers,

Mark