LGPL relicense port of rsync

Florian Sager sager at agitos.de
Fri Jan 8 23:13:14 UTC 2016

Am 07.01.2016 um 23:26 schrieb Per Lundqvist:
> Hi,
> I am maintaining a port of rsync (https://github.com/perlundq/yajsync)
> which is GPL:ed of course. The main purpose of the project is to
> provide a Java API library for the rsync protocol. It would
> therefore be really nice to be able to use LGPL as the license.
> But in order to do so I would first have to get a list of all the
> individual contributors to rsync and then be able to contact them and
> ask them to agree to this and also verify their identity. I do however suspect
> this to be an almost impossible task...
> Is this as futile as it seems? ;)
> And is there a complete list of contributors available somewhere?
> thanks,
> --
> Per Lundqvist

Hi Per,

relicensing the yajsync library with LGPL might be a precondition for
the longterm awareness and survivability of the yajsync project. So it's
really worth the attempt to relicense.
I saw that librsync is as well LGPL'ed. In my view it would have never
gotten the attention and usage/linkage it has today with being GPL'ed only.

Getting the approval for a relicensing I think the contributions to
rsync have to be analyzed in detail to approach a reasonable number of
I experienced that finding a responsible person that is willing to
discuss such a case in an organization that contributed source code is
nearly impossible.

Looking at the source code (my short analysis refers to rsync-3.1.1)
some questions come to my mind to simplify the relicensing discussion:
- the GPL headers in the source code mention copyright owners: might it
be sufficient to approach these copyright owners and leave out every
patch author?
- the yajsync implementation refers to a subset of rsync: does the
derivative work comprise only the according parts of the rsync source code?
- supposed some parts of yajsync were developed looking at the rsync
interface definition (the man page) only [I can state this for the small
parts I contributed to yajsync]. Are these parts still derivative work
to rsync?
- supposed an author contributed a part of rsync like the md5
implementation that is not in use in yajsync because of a Java
replacement: does such an author have to be approached?

Focusing on the source code only without tests, config scripts and free
libraries (zlib and popt) and without common knowledge functions like
md5 or sprintf or getaddrinfo or getpass and without rsync-batch I come
up with the following individuals being mentioned with a copyright:

Wayne Davison
Andrew Tridgell
Martin Pool
Jeremy Allison (maybe only indirectly by code copy)
Paul Mackerras
Scott Howard

Maybe you could approach these people first to get the process started.


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