Re: [PATCH bpf-next v2 2/2] Add table of BPF program types to libbpf docs

[Donald Hunter <donald.hunter@gmail.com>]

Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:
>
>>  libbpf
>>  ======
>>
>> @@ -9,6 +11,7 @@ libbpf
>>     API Documentation <https://libbpf.readthedocs.io/en/latest/api.html>
>
> I'd put program_types here, it's more relevant and important than
> libbpf naming conventions

Good suggestion, thanks.

>>     libbpf_naming_convention
>>     libbpf_build
>> +   program_types
>>
>>  This is documentation for libbpf, a userspace library for loading and
>>  interacting with bpf programs.
>> diff --git a/Documentation/bpf/libbpf/program_types.rst b/Documentation/bpf/libbpf/program_types.rst
>> new file mode 100644
>> index 000000000000..dc65ede09eef
>> --- /dev/null
>> +++ b/Documentation/bpf/libbpf/program_types.rst
>> @@ -0,0 +1,18 @@
>> +.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
>> +
>> +.. _program_types_and_elf:
>> +
>> +Program Types  and ELF Sections
>
> nit: two spaces?

Ack.

>> +===============================
>> +
>> +The table below lists the program types, their attach types where relevant and the ELF section
>> +names supported by libbpf for them. The ELF section names follow these rules:
>> +
>> +- ``type`` is an exact match, e.g. ``SEC("socket")``
>> +- ``type+`` means it can be either exact ``SEC("type")`` or well-formed ``SEC("type/extras")``
>> +  with a ‘``/``’ separator, e.g. ``SEC("tracepoint/syscalls/sys_enter_open")``
>
> '/' is always going to be a type and "extras" separator, but extra
> section format is not formalized. We have cases where it's all '/'s
> (like tracepoint you mentioned), but newer and more complicated format
> uses ':' as separator, e.g.
> SEC("usdt/<path-to-binary>:<usdt_provide>:<usdt_name>") (let's mention
> the latter as well to not create false impression of only ever having
> '/' as separator)

I will add a more detailed description extras format and include the
USDT example.

>> +
>> +.. csv-table:: Program Types and Their ELF Section Names
>> +   :file: ../../output/program_types.csv
>> +   :widths: 40 30 20 10
>> +   :header-rows: 1
>
> it would be helpful to include a short snippet from generated CSV file
> to give a general idea of the output

Ack.