Re: [PATCH net-next 2/2] tools: bpf: add bpftool

[Daniel Borkmann <daniel@iogearbox.net>]

On 09/27/2017 12:45 PM, Jesper Dangaard Brouer wrote:
> On Wed, 27 Sep 2017 00:02:08 +0100
> Jakub Kicinski <jakub.kicinski@netronome.com> wrote:
>> On Tue, 26 Sep 2017 15:24:06 -0700, Alexei Starovoitov wrote:
>>> On Tue, Sep 26, 2017 at 08:35:22AM -0700, Jakub Kicinski wrote:
>>>> Add a simple tool for querying and updating BPF objects on the system.
>>>>
>>>> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
>>>> Reviewed-by: Simon Horman <simon.horman@netronome.com>
> [...]
>>>>   tools/bpf/Makefile             |  18 +-
>>>>   tools/bpf/bpftool/Makefile     |  80 +++++
>>>>   tools/bpf/bpftool/common.c     | 214 ++++++++++++
>>>>   tools/bpf/bpftool/jit_disasm.c |  83 +++++
>>>>   tools/bpf/bpftool/main.c       | 212 ++++++++++++
>>>>   tools/bpf/bpftool/main.h       |  99 ++++++
>>>>   tools/bpf/bpftool/map.c        | 742 +++++++++++++++++++++++++++++++++++++++++
>>>>   tools/bpf/bpftool/prog.c       | 392 ++++++++++++++++++++++
>>>>   8 files changed, 1837 insertions(+), 3 deletions(-)
>>> ...
>>>> +static int do_help(int argc, char **argv)
>>>> +{
>>>> +	fprintf(stderr,
>>>> +		"Usage: %s %s show   [MAP]\n"
>>>> +		"       %s %s dump    MAP\n"
>>>> +		"       %s %s update  MAP  key BYTES value VALUE [UPDATE_FLAGS]\n"
>>>> +		"       %s %s lookup  MAP  key BYTES\n"
>>>> +		"       %s %s getnext MAP [key BYTES]\n"
>>>> +		"       %s %s delete  MAP  key BYTES\n"
>>>> +		"       %s %s pin     MAP  FILE\n"
>>>> +		"       %s %s help\n"
>>>> +		"\n"
>>>> +		"       MAP := { id MAP_ID | pinned FILE }\n"
>>>> +		"       " HELP_SPEC_PROGRAM "\n"
>>>> +		"       VALUE := { BYTES | MAP | PROG }\n"
>>>> +		"       UPDATE_FLAGS := { any | exist | noexist }\n"
>>>> +		"",
>>>
>>> overall looks good to me, but still difficult to grasp how to use it.
>>> Can you add README with example usage and expected output?
>>
>> I have a README on GitHub, but I was thinking about perhaps writing a
>> proper man page?  Do you prefer one over the other?
>
> I would prefer adding a README.rst file, in RST-format, as the rest of
> the kernel documentation is moving in that direction[1] (your github
> version is in README.md format).  A man page will always be
> out-of-sync, and even out-of-sync on different distros.
>
>   See[1]: https://www.kernel.org/doc/html/latest/
>
> And then I would find some place in Documentation/admin-guide/ and
> include the README.rst file, so it shows up at [1].
>
> RST have an include method like:
>
> .. include:: ../../tools/bpf/bpftool/README.rst

Agree, to have a README.rst with a description/howto in bpftool/
seems like a good idea to me, too.

Thanks,
Daniel