Re: [PATCH bpf-next v4] tools/bpf: generate pkg-config file for libbpf

From: Daniel Borkmann <daniel@iogearbox.net>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Andrey Ignatov <rdna@fb.com>
Cc: "luca.boccassi@gmail.com" <luca.boccassi@gmail.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next v4] tools/bpf: generate pkg-config file for libbpf
Date: Thu, 21 Mar 2019 23:19:19 +0100	[thread overview]
Message-ID: <80186d7b-ff21-e81f-1320-5916ecfcc99b@iogearbox.net> (raw)
In-Reply-To: <20190321220107.pcvf6e23kun4gj7r@ast-mbp.dhcp.thefacebook.com>

On 03/21/2019 11:01 PM, Alexei Starovoitov wrote:
> On Thu, Mar 21, 2019 at 04:00:46PM +0000, Andrey Ignatov wrote:
>> luca.boccassi@gmail.com <luca.boccassi@gmail.com> [Thu, 2019-03-21 03:26 -0700]:
>>> From: Luca Boccassi <bluca@debian.org>
>>>
>>> Generate a libbpf.pc file at build time so that users can rely
>>> on pkg-config to find the library, its CFLAGS and LDFLAGS.
>>>
>>> Signed-off-by: Luca Boccassi <bluca@debian.org>
> ...
>>> diff --git a/tools/lib/bpf/libbpf.pc.template b/tools/lib/bpf/libbpf.pc.template
>>> new file mode 100644
>>> index 000000000000..0ecd334c109f
>>> --- /dev/null
>>> +++ b/tools/lib/bpf/libbpf.pc.template
>>> @@ -0,0 +1,11 @@
>>> +prefix=@PREFIX@
>>> +libdir=@LIBDIR@
>>> +includedir=${prefix}/include
>>> +
>>> +Name: libbpf
>>> +URL: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>> +Description: Linux kernel BPF library
> 
> github/libbpf/libbpf is a true mirror of kernel's libbpf.
> I think if we start shipping libbpf.so from kernel and from github
> it will be very confusing to the users...
> Which one is the true libbpf?
> Also the package should mention the license.
> And the license for libbpf is dual lgpl/bsd.
> But if we point to the url above it will not make much sense.
> I think the packages URL should point to github/libbpf/libbpf
> and packaging scripts should be in github only.
> 
> Daniel,
> what do you think?

Looking at [0], I don't see where license would be part of the keyword. Given
this is just a pkg-config file where folks using it care mainly about the
needed cflags/libs, it would make sense to me to ship it and have it under
tools/lib/bpf/ in kernel tree (since this is distro independent). If the URL
and Description causes confusion, I would probably just remove the URL field
since it's not mandatory either. And description, I'd put something like
'official BPF library' or such, so it's generic enough.

  [0] https://autotools.io/pkgconfig/file-format.html
      https://dev.gentoo.org/~mgorny/pkg-config-spec.html#keywords