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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Tue, 15 Mar 2022 16:39:10 -0700
Message-ID: <CAADnVQ+bkyPPA9r_n+A7VeYQch-fOiPDHGO-2EZ1dhgva8GF8Q@mail.gmail.com>
Subject: Re: [PATCH bpf-next] bpftool: Add SPDX identifier to btf-dump-file output
To:     Daniel Xu <dxu@dxuuu.xyz>
Cc:     "bpf@vger.kernel.org" <bpf@vger.kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, Mar 15, 2022 at 4:10 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
>
> Hi Alexei,
>
> On Tue, Mar 15, 2022, at 2:38 PM, Alexei Starovoitov wrote:
> > On Sun, Mar 13, 2022 at 4:01 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
> >>
> >> A concern about potential GPL violations came up at the new $DAYJOB when
> >> I tried to vendor the vmlinux.h output. The central point was that the
> >> generated vmlinux.h does not embed a license string -- making the
> >> licensing of the file non-obvious.
> >>
> >> This commit adds a LGPL-2.1 OR BSD-2-Clause SPDX license identifier to
> >> the generated vmlinux.h output. This is line with what bpftool generates
> >> in object file skeletons.
> >>
> >> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> >> ---
> >>  tools/bpf/bpftool/btf.c | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
> >> index a2c665beda87..fca810a27768 100644
> >> --- a/tools/bpf/bpftool/btf.c
> >> +++ b/tools/bpf/bpftool/btf.c
> >> @@ -425,6 +425,7 @@ static int dump_btf_c(const struct btf *btf,
> >>         if (err)
> >>                 return err;
> >>
> >> +       printf("/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */\n\n");
> >
> > I don't think we can add any kind of license identifier
> > to the auto generated output.
> > vmlinux.h is a pretty printed dwarfdump.
>
> Just so I understand better, when you say "I don't think we can",
> do you mean:
>
> 1) There may be legal issues w/ adding the license identifier
> 2) It doesn't make sense to add the license header
> 3) Something else?

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