RTEMS Documentation BSD licensing

[Sebastian Huber]

Hello Martin,

On 06/03/2020 19:36, Martin Erik Werner wrote:
> Based on the dual-licensing work done as part of
> https://devel.rtems.org/ticket/3899 I was wondering what the licensing
> state would be for the documentation going forward?
> 
> Previously, as far as I understand it, contributions were implicitly
> licensed under BY-SA (CC-BY-SA-4.0 international) by the author and
> RTEMS uses and redistributes the content with this license?

yes.

> 
> With this dual-licensing I understand that contributions will now be
> implicitly licensed under both BSD (BSD-2-Clause) and BY-SA by the
> author for contributions to some (or all?) parts.
> 
> Is there any documentation that will indicate this more specifically?
> "If you contribute to this item, your agre to provide your
> contributions under this(these) license(s)".

What matters from my point of view is the license header of the 
individual files. For the documentation we don't have guidelines 
included in the RTEMS Software Engineering manual. Maybe we should start 
with this and mention the licencing background.

For the RTEMS Qualification Project I would like to generate content 
from the specification. For example, we have documentation of API 
functions in Doxygen and the Classic API Guide:

https://docs.rtems.org/doxygen/branches/master/group__ClassicTasks.html#gabffda1c2301962f0ae5af042ac0bba62

https://docs.rtems.org/branches/master/c-user/task_manager.html#task-create-create-a-task

One goal of the pre-qualification activity is to introduce a master data 
set (specification) and use tools to generate content in the right 
format from it. The specification consists of individual files with 
attributes (key-value pairs), for example:

https://git.rtems.org/sebh/rtems-qual.git/tree/spec/glos/term/RTEMS-GLOS-TERM-TASK.yml

The files have a license and copyrights attribute, e.g.

SPDX-License-Identifier: CC-BY-SA-4.0
copyrights:
- Copyright (C) 2017 embedded brains GmbH (http://www.embedded-brains.de)
- Copyright (C) 1988, 1998 On-Line Applications Research Corporation (OAR)

For a generated document this information is aggregated and checked that 
the target license is compatible to all the individual contributions, e.g.

https://git.rtems.org/rtems-docs/tree/c-user/glossary.rst

This file was generated by:

https://git.rtems.org/sebh/rtems-qual.git/tree/rtems_spec_to_x.py

If we want to generate also Doxygen markup for header files, then the 
specification items need a dual CC-BY-SA-4.0 or BSD-2-Clause license so 
that the RTEMS sources are still BSD-2-Clause. My task is now to collect 
existing content form the RTEMS documentation and sources to build up 
the specification items. For this I have to be very careful with the 
copyright and license information.

> 
> Will the documentation with inbound BSD/BY-SA contributions still be
> outbound licensed under BY-SA in the "web" documentation? Or will this
> documenation shift to being outbound BSD/BY-SA as well?

The published documentation will be CC-BY-SA-4.0. Only some 
documentation sources (or specification items) will have a dual license.

> 
> BSD is inbound compatible with BY-SA, right? If so I would guess that
> providing contributions under BSD would be the same as providing them
> under BSD and BY-SA (since one can simply take BSD and make it BY-SA)?

I am not sure.

> 
> Assuming that BSD is inbound compatible with BY-SA, would it then make
> sense to use only BSD as both inbound and outbound for the doxygen-
> shared part of the "web" documentation?

I think using

SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause

for content intended for the RTEMS sources and documentation makes it 
clear. This reasoning about license transformations is not really my 
area of expertise.

> 
> If it remains outbound BY-SA-only there would be an assymetry, and for
> example have the mild hitch that only the RTEMS project itself is
> allowed to copy documentation to BSD-doxygen.

The RTEMS Project is not a copyright holder. The license of a document 
is determined by the licenses of the source files.

-- 
Sebastian Huber, embedded brains GmbH

Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone   : +49 89 189 47 41-16
Fax     : +49 89 189 47 41-09
E-Mail  : sebastian.huber at embedded-brains.de
PGP     : Public key available on request.

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