Re: [Qemu-devel] [PATCH v2 2/4] slirp: clarify license of slirp files using SPDX

[Eric Blake]

On 3/13/19 11:42 AM, Marc-André Lureau wrote:
> The slirp source files have different license headers, sometime
> partial, sometime refering to COPYRIGHT file. All files under slirp

referring

> are BSD-3. Add SPDX license identifier to clarify the license.
> 
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---

This one needs a full audit for accuracy; I'm in favor of it, but don't
have time to complete the audit at the moment.  Here's what I've done so
far:

> +++ b/slirp/src/bootp.h
> @@ -1,3 +1,4 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */
>  /* bootp/dhcp defines */

No previous license notice, this change makes explicit what was
previously implicit (and, as patch 1/4 noted, commit 2f5f8996 documents
that slirp changed to 3-clause).

>  
>  #ifndef SLIRP_BOOTP_H
> diff --git a/slirp/src/debug.h b/slirp/src/debug.h
> index 44d922df37..2e503ad7fa 100644
> --- a/slirp/src/debug.h
> +++ b/slirp/src/debug.h
> @@ -1,3 +1,4 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */
>  /*
>   * Copyright (c) 1995 Danny Gasparovski.

This one referred to 'COPYRIGHT' without stating an explicit license;
the file slirp/COPYRIGHT appears to be a 2-clause BSD, whereas the tag
is now calling out 3-clause. I'm not sure if that could be problematic,
so I'm mentioning it as a question.  But my understanding is that going
from 2-clause to 3-clause is acceptable for the same reason that going
from BSD to GPL is acceptable: you are strengthening the license (not
weakening it), and the first two clauses were permissive enough to allow
you to make that strengthening.

>   *
> diff --git a/slirp/src/dhcpv6.h b/slirp/src/dhcpv6.h
> index af0e193b06..dc26a93cff 100644
> --- a/slirp/src/dhcpv6.h
> +++ b/slirp/src/dhcpv6.h
> @@ -1,3 +1,4 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */
>  /*

This was just explicitly changed in 1/4, so it matches perfectly.

>   * Definitions and prototypes for SLIRP stateless DHCPv6
>   *
> diff --git a/slirp/src/if.h b/slirp/src/if.h
> index 69569c10df..8a60c4e052 100644
> --- a/slirp/src/if.h
> +++ b/slirp/src/if.h
> @@ -1,3 +1,4 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */

Another reference solely to ambiguous COPYRIGHT, which I take to mean
slirp/COPYRIGHT, and thus this changes 2-clause to 3-clause.

>  /*
>   * Copyright (c) 1995 Danny Gasparovski.
>   *
> diff --git a/slirp/src/ip.h b/slirp/src/ip.h
> index 73a4d2a3d2..1484de1176 100644
> --- a/slirp/src/ip.h
> +++ b/slirp/src/ip.h

And that's as far as I got today.

I hate to make you split patches even more (thanks for already making
the splits for v2), but I wonder if it would be easier to split this
into trivial changes (those where the tag is added to a file that
explicitly has the license that the tag is re-affirming) vs. potentially
questionable changes (those where the tag is added to a file that has
nothing at all, and those where the tag is added to a file referring to
2-clause COPYRIGHT and tightening up to 3-clause).  You may want to get
a second opinion before giving yourself busy-work.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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