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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Tue, 15 Mar 2022 14:38:06 -0700
Message-ID: <CAADnVQJUvfKmN6=j5hzhgE25XSa2uqR3MJyq+c=AGCKkTKD05g@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 <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 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.