On 04/16/2019 02:54 AM, Andrii Nakryiko wrote: > On Thu, Apr 11, 2019 at 8:38 AM Yonghong Song <y...@fb.com> wrote: >> >> cc Andrii >> >> On 4/11/19 12:51 AM, Daniel Borkmann wrote: >>> On 04/10/2019 05:39 PM, Jakub Kicinski wrote: >>>> On Wed, 10 Apr 2019 13:56:42 +0900, Prashant Bhole wrote: >>>>> Let's add a way to know whether a program has btf context. >>>>> Patch adds 'btf_id' in the output of program listing. >>>>> When btf_id is present, it means program has btf context. >>>>> >>>>> Sample output: >>>>> user@test# bpftool prog list >>>>> 25: xdp name xdp_prog1 tag 539ec6ce11b52f98 gpl >>>>> loaded_at 2019-04-10T11:44:20+0900 uid 0 >>>>> xlated 488B not jited memlock 4096B map_ids 23 >>>>> btf_id 1 >>>>> >>>>> Signed-off-by: Prashant Bhole <bhole_prashant...@lab.ntt.co.jp> >>>> >>>> Acked-by: Jakub Kicinski <jakub.kicin...@netronome.com> >>> >>> Applied, thanks! >>> >>> What would be the plan for the maps listing? >> [...] >>> I think what we could also potentially have is some way to dump >>> the BTF type info based on such above id. Perhaps it would make >>> sense to similarly share the verifier's printer with bpftool? >> >> Agreed. It does make sense to print the detailed info for a btf id >> through bpftool. >> >> Andrii had a btf dumper to dump types as well as BTF elf file .btf.ext >> contents in his private branch. Maybe Andrii can comment further >> on this subject. > > Yes, absolutely, we should have this as part of bpftool. I'm going to > start porting this logic from my private prototype very soon. > > I think we should be able to have both low-level (though still > human-readable) BTF dump as close to underlying BTF data as possible, > as well as an ability to dump struct/union/datasec definitions in > compilable C format. E.g., for struct/union it will be struct/union > definition, as well as all the necessary dependent types, for > datasec/vars it will be a list of global variables declaration w/ all > the necessary types. Thoughts?
Yes, that sounds great to me! Both is needed. For the latter, it would also be useful if I could do e.g. a bpftool prog btf dump id xyz and it will show a pahole like output where I can see offset, padding information as well as size + cachelines needed for all types used by the loaded BPF program. Thanks, Daniel
