[External] Re: [PATCH bpf-next v2 8/9] libbpf: add support for the multi-link of tracing

[梦龙董]

On Mon, Mar 11, 2024 at 11:29 PM Quentin Monnet <quentin at isovalent.com> wrote:
>
> 2024-03-11 09:35 UTC+0000 ~ Menglong Dong <dongmenglong.8 at bytedance.com>
> > Add support for the attach types of:
> >
> > BPF_TRACE_FENTRY_MULTI
> > BPF_TRACE_FEXIT_MULTI
> > BPF_MODIFY_RETURN_MULTI
> >
> > Signed-off-by: Menglong Dong <dongmenglong.8 at bytedance.com>
> > ---
> >  tools/bpf/bpftool/common.c |   3 +
> >  tools/lib/bpf/bpf.c        |  10 +++
> >  tools/lib/bpf/bpf.h        |   6 ++
> >  tools/lib/bpf/libbpf.c     | 168 ++++++++++++++++++++++++++++++++++++-
> >  tools/lib/bpf/libbpf.h     |  14 ++++
> >  tools/lib/bpf/libbpf.map   |   1 +
> >  6 files changed, 199 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> > index cc6e6aae2447..ffc85256671d 100644
> > --- a/tools/bpf/bpftool/common.c
> > +++ b/tools/bpf/bpftool/common.c
> > @@ -1089,6 +1089,9 @@ const char *bpf_attach_type_input_str(enum bpf_attach_type t)
> >       case BPF_TRACE_FENTRY:                  return "fentry";
> >       case BPF_TRACE_FEXIT:                   return "fexit";
> >       case BPF_MODIFY_RETURN:                 return "mod_ret";
> > +     case BPF_TRACE_FENTRY_MULTI:            return "fentry_multi";
> > +     case BPF_TRACE_FEXIT_MULTI:             return "fexit_multi";
> > +     case BPF_MODIFY_RETURN_MULTI:           return "mod_ret_multi";
> >       case BPF_SK_REUSEPORT_SELECT:           return "sk_skb_reuseport_select";
> >       case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE:        return "sk_skb_reuseport_select_or_migrate";
> >       default:        return libbpf_bpf_attach_type_str(t);
>
> Hi, please drop this part in bpftool.
>
> bpf_attach_type_input_str() is used for legacy attach type names that
> were used before bpftool switched to libbpf_bpf_attach_type_str(), and
> that are still supported today. The names for new attach types should
> just be retrieved with libbpf_bpf_attach_type_str(). And function
> bpf_attach_type_input_str() is also only used for attaching
> cgroup-related programs with "bpftool cgroup (at|de)tach".

Okay! I was confused about this function, which has reduplicated
information about the attach type name, and I understand it now.

Thanks!
Menglong Dong

>
> Thanks,
> Quentin
>