libbpf - why find_program_by_title ?

libbpf - why find_program_by_title ?

[Jesper Dangaard Brouer]

Hi Andrii,

The libbpf API bpf_program__title() is getting depricated (which is 
great BTW). (p.s. Instead use bpf_program__section_name()).

Why do we still have bpf_object__find_program_by_title() ?

Shouldn't we also deprecate that?
And introduce bpf_object__find_program_by_section_name().

--Jesper

Re: libbpf - why find_program_by_title ?

[Andrii Nakryiko]

On Thu, Oct 28, 2021 at 5:02 AM Jesper Dangaard Brouer
<jbrouer@redhat.com> wrote:
>
> Hi Andrii,
>
> The libbpf API bpf_program__title() is getting depricated (which is
> great BTW). (p.s. Instead use bpf_program__section_name()).
>
> Why do we still have bpf_object__find_program_by_title() ?
>
> Shouldn't we also deprecate that?

Yes, we should and we plan, see [0]. The only reason why it's not yet
marked as deprecated is because there are still a lot of uses of
find_program_by_title in selftests and we need to clean that up first.
It would be great to get help with that, of course.


  [0] https://github.com/libbpf/libbpf/issues/292

> And introduce bpf_object__find_program_by_section_name().

I didn't plan to because there is (in general) more than one program
for the same section name (section names are not unique identifiers
for a while now), so which program this API would return: first, last,
random? It's just wrong API with wrong assumptions.

The right way to go about this is to do a loop over all programs with
bpf_object__for_each_program(prog, obj) and compare
bpf_program__section_name() explicitly. And then do whatever your
application needs to do with every instance of the program with
matching section name.

>
> --Jesper
>