On Fri, Jun 16, 2023 at 10:18 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote:
>
> Provide a way to dump BTF metadata info via bpftool; this
> consists of BTF size, header fields and kind layout info
> (if available); for example
>
> $ bpftool btf dump file vmlinux format meta
> size 4966513
> magic 0xeb9f
> version 1
> flags 0x0
> hdr_len 24
> type_len 2929900
> type_off 0
> str_len 2036589
> str_off 2929900
>
> ...or for vmlinux with kind layout, crc:
>
> $ bpftool btf dump file vmlinux format meta
> size 5034496
> magic 0xeb9f
> version 1
> flags 0x1
> hdr_len 40
> type_len 2973628
> type_off 0
> str_len 2060745
> str_off 2973628
> kind_layout_len 80
> kind_layout_off 5034376
> crc 0xb6a5171f
> base_crc 0x0
> kind 0 flags 0x0 info_sz 0 elem_sz 0
> kind 1 flags 0x0 info_sz 4 elem_sz 0
> kind 2 flags 0x0 info_sz 0 elem_sz 0
> kind 3 flags 0x0 info_sz 12 elem_sz 0
> kind 4 flags 0x0 info_sz 0 elem_sz 12
well, bpftool will know symbolic names for most of these, so why not
emit them? I think it's fine to emit both, something like
kind INT (1) flags ....
...
and for unknown:
kind <unknown> (123) flags ....
WDYT?
> ...
>
> JSON output is also supported:
>
> $ bpftool -j btf dump file vmlinux format meta
> {"size":4904369,{"header":"magic":60319,"version":1,"flags":0,"hdr_len":24,"type_len":2893508,"type_off":0,"str_len":2010837,"str_off":2893508}}
>
> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> ---
> tools/bpf/bpftool/bash-completion/bpftool | 2 +-
> tools/bpf/bpftool/btf.c | 93 ++++++++++++++++++++++-
> 2 files changed, 92 insertions(+), 3 deletions(-)
>
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