On Thu, May 19, 2022 at 12:18:03AM +0000, Daniel Müller wrote:
> This patch set introduces the means for querying a textual representation of
> the following BPF related enum types:
> - enum bpf_map_type
> - enum bpf_prog_type
> - enum bpf_attach_type
> - enum bpf_link_type
>
> To make that possible, we introduce a new public function for each of the types:
> libbpf_bpf_<type>_type_str.
>
> Having a way to query a textual representation has been asked for in the past
> (by systemd, among others). Such representations can generally be useful in
> tracing and logging contexts, among others. At this point, at least one client,
> bpftool, maintains such a mapping manually, which is prone to get out of date as
> new enum variants are introduced. libbpf is arguably best situated to keep this
> list complete and up-to-date. This patch series adds BTF based tests to ensure
> that exhaustiveness is upheld moving forward.
>
> The libbpf provided textual representation can be inferred from the
> corresponding enum variant name by removing the prefix and lowercasing the
> remainder. E.g., BPF_PROG_TYPE_SOCKET_FILTER -> socket_filter. Unfortunately,
> bpftool does not use such a programmatic approach for some of the
> bpf_attach_type variants. We decided changing its behavior to work with libbpf
> representations. However, for user inputs, specifically, we do keep support for
> the traditionally used names around (please see patch "bpftool: Use
> libbpf_bpf_attach_type_str").
>
> The patch series is structured as follows:
> - for each enumeration type in {bpf_prog_type, bpf_map_type, bpf_attach_type,
> bpf_link_type}:
> - we first introduce the corresponding public libbpf API function
> - we then add BTF based self-tests
> - we lastly adjust bpftool to use the libbpf provided functionality
>
> Changelog:
> v1 -> v2:
> - adjusted bpftool to work with algorithmically determined attach types as
> libbpf now uses (just removed prefix from enum name and lowercased the rest)
> - adjusted tests, man page, and completion script to work with the new names
> - renamed bpf_attach_type_str -> bpf_attach_type_input_str
> - for input: added special cases that accept the traditionally used strings as
> well
> - changed 'char const *' -> 'const char *'
I forgot to add the following: this patch set will need another revision in
order to integrate with Andrii's
https://patchwork.kernel.org/project/netdevbpf/patch/20220518185915.3529475-3-andrii@xxxxxxxxxx/
once merged. This revision is mostly send out to get more feedback for the
changes to bpftool, which are rather significant.
Thanks,
Daniel
