On Wed, Feb 12, 2020 at 5:05 AM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote:
>
> Eelco Chaudron <echaudro@xxxxxxxxxx> writes:
>
> > Currently when you want to attach a trace program to a bpf program
> > the section name needs to match the tracepoint/function semantics.
> >
> > However the addition of the bpf_program__set_attach_target() API
> > allows you to specify the tracepoint/function dynamically.
> >
> > The call flow would look something like this:
> >
> > xdp_fd = bpf_prog_get_fd_by_id(id);
> > trace_obj = bpf_object__open_file("func.o", NULL);
> > prog = bpf_object__find_program_by_title(trace_obj,
> > "fentry/myfunc");
> > bpf_program__set_attach_target(prog, xdp_fd,
> > "fentry/xdpfilt_blk_all");
>
> I think it would be better to have the attach type as a separate arg
> instead of encoding it in the function name. I.e., rather:
>
> bpf_program__set_attach_target(prog, xdp_fd,
> "xdpfilt_blk_all", BPF_TRACE_FENTRY);
I agree about not specifying section name prefix (e.g., fentry/). But
disagree that expected attach type (BPF_TRACE_FENTRY) should be part
of this API. We already have bpf_program__set_expected_attach_type()
API, no need to duplicate it here.
>
> -Toke
>
