[RFC/fix] Re: libbpf build broken on musl libc (Alpine Linux)

From: Arnaldo Carvalho de Melo
Date: Thu Sep 13 2018 - 14:32:46 EST

Em Tue, Sep 11, 2018 at 02:24:53PM -0700, Alexei Starovoitov escreveu:
> On Tue, Sep 11, 2018 at 09:15:43AM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Tue, Sep 11, 2018 at 12:22:18PM +0200, Jakub Kicinski escreveu:
> > > On Mon, 10 Sep 2018 14:29:03 -0300, Arnaldo Carvalho de Melo wrote:
> > > > After lunch I'll work on a patch to fix this,
> > > Any luck?

> > Well, we need to apply the patch below and make tools/lib/str_error_r.c
> > live in a library that libbpf and perf is linked to.

> do you want us to take the patch or you're applying it yourself?

Please do some testing with my perf/libbpf+str_error_r branch, it has
two patches to get this fixed, the one I sent and a prep one making
libbpf link against libapi.

[acme@jouet perf]$ git log --oneline -2
a7ab924b7fec (HEAD -> perf/urgent, acme.korg/perf/libbpf+str_error_r) tools lib bpf: Use str_error_r() to fix the build in Alpine Linux
fb4a79e04c2b tools lib bpf: Build and link to tools/lib/api/
[acme@jouet perf]$

I did a lot of tests to make sure tools/perf, tools/lib/bpf,
tools/bpf/bpftools and the bpf selftests all build as expected, with
OUTPUT= and in place.

The csets have further comments about tricky aspects of this.

- Arnaldo