woah, complication

[adns.git] / GPL-vs-LGPL

NB that NO VERSIONS of this file from this branch have been released,
and I do not intend yet to publish this version.  If you get an old
version of this file from my CVS repository definitely do not intend
the licence exceptions in it to apply - these too were drafts, as you
should know if you know what retreiving old CVS versions means !

  - Ian Jackson, 9th March 2004.

DRAFT - DRAFT - DRAFT - DRAFT - DRAFT - DRAFT - DRAFT - DRAFT - DRAFT

              GPL vs LGPL, in the context of adns
              -----------------------------------

Several people have asked me to release adns under the GNU Lesser
General Public Licence (LGPL, formerly the Library GPL) instead of the
`stronger' GPL.  This file is intended to answer most of these
questions.  If you still have questions or comments, please mail me at
<adns-maint@chiark.greenend.org.uk>.

Typically there are two or three kinds of situation where people make
this request: the first is where someone is developing a proprietary
program and wishes to make use of adns but doesn't wish to make their
program free software.  The second case is where a free software
project is currently using an MIT-like licence and fear `GPL
infection'.  The third case, which often overlaps with the second, is
where another free software project currently using a GPL-incompatible
licence, wishes to use adns.


1. Proprietary applications of adns
-----------------------------------

This section applies if you are developing a proprietary program, by
which I mean that you will not be distributing source code and not
allowing users to modify and share your software; in most cases you
will be doing this for (personal or corporate) financial gain.

In these cases I may be prepared to issue you a special `LGPL' for
adns (ie, allow you to use adns in your application according to the
terms of the LGPL).  I will of course expect a significant licensing
fee.

If you are interested I would be happy to negotiate with you.  Please
contact me with your serious initial offer, or if alternatively we can
first discuss your detailed requirements.

The fee for proprietary applications of adns without prior approval is
US$1,000,000 per annum (or part thereof), per proprietary product, per
100,000 installed systems (or part thereof), plus any administration,
collection and legal fees required to recover the licence fee.  Of
course, this does not apply to commercial Free software applications
whose use of adns is compatible with the GNU GPL v2.


2. GPL-avoiding projects (MIT licence, et al)
---------------------------------------------

Some free software projects prefer to avoid the GPL and other licences
which force the software always to be free.  Instead they use
something like the MIT X licence, which allows proprietary versions of
their software.  I have to say that I don't understand why they do
this, and think they are misguided, but that doesn't mean that they
don't have a perfect right to.

Some of these people think that merely writing to an interface
provided by GPL'd software will cause their program to become GPL'd
too, even if they don't distribute the GPL'd software.  I don't think
this is the case.  I'm perfectly happy for non-GPL'd software to refer
to adns in its source code or executables (eg, dynamic linking).
However, if you distribute adns yourself then whether a program which
uses it needs also to be GPL'd depends on the interpretation of the
`work as a whole' and `mere aggregation' parts of the GPL.

Whether you are distributing a `work as a whole' might depend on many
things, but they key one to me is what the appearance is to a user.
If the user knows that they are getting a collection of software
rather than a single product, then it's probably an aggregation which
works together.  So, you can distribute both your (i) non-GPLd program
source and/or binaries and (ii) adns source code or even binaries
(provided the adns source is available as per the GPL), eg from your
website, provided the user can tell that these are separate works and
can tell which parts are which.

But, if you package your program and adns together so that the user is
no longer aware of adns as a separate work, then I think you are
distributing a `work as a whole', and the whole work including adns
and your software which depends on it must be GPL'd.  This is of
course not a problem if your non-GPL licence is GPL-compatible (see
the next section): it just means that _when the whole lot is shipped
together as one work_ it is covered by the GPL.  People who wish to
make proprietary works based on just your code can do so, provided
they (or you) arrange for something to fill the hole left by the lack
of adns.


3. GPL-incompatible free software licences
------------------------------------------

Regrettably, there are a number of free software licences (and
semi-free licences) in existence which are not compatible with the
GPL.  That is, they impose restrictions which are not present in the
GPL, and therefore distributing a whole work which contains such a
program and a GPL'd program is not possible: either the work would
have to be distributed under the GPL (violating the restrictions made
by the original author), or under the GPL-incompatible licence
(violating the GPL).

I may be prepared to make exceptions for such a licence.  Please
contact me at <adns-maint@chiark.greenend.org.uk> with the full text
of the GPL-incompatible licence.  However, I would prefer it if you
could use a GPL-compatible licence for your project instead.

There are a couple of common extra restrictions, and I make some
specific extensions to my licence for adns below.


3.1. BSD advertising clause, endorsement restriction, etc.

The most notable and common extra restriction found in free software
licences is the `obnoxious BSD advertising clause' (see Richard
Stallman's article on the subject, available from www.gnu.org) and the
endorsement restriction.

The problem with the advertising clause isn't that the sentence
required, referring the the Regents of the UC Berkeley, is awkward.
The problem is that if everyone contributing to a large project gets
such a mention the number of sentences required becomes very large;
however, it is unfair for some people to get credit and others not to.

I disapprove of these clause, but I recognise that it may be difficult
for some people to get them removed from particular programs.  The
other clauses are also arguable.


3.2. `Hosting service' restriction (eg, Affero GPL)

The additional restriction in the AGPL v1 (section 2d) seems
reasonable to me, in the circumstances.


3.3. Licence extension

So, I hereby make an extension to my licence for adns (`the Original
Work' in the text below).


 LICENCE DEROGATION
 ------------------

 (A) Introduction:

  (i)    The GNU GPL version 2, section 2b, and the later parts of
         section 2, require that certain works be licenced to all
         third parties under the terms of the GPL.

  (ii)   As special relaxations of this requirement, described in
         detail below, the terms of this onward licence to third
         parties need not be (though they may be) exactly the terms of
         the GPLv2.

 (B) Preconditions:

  (i)    There is a work (the `Original Work') which is licensed under
         the GNU GPL v2.

  (ii)   There is a work (the `GPL'd Work'), either the same work as
         the Original Work, or derived work of the Original Work,
         which is licensed uner the GNU GPL v2.

  (iii)  All of the copyright holders of the GPL'd Work state that
         this Licence Derogation is to apply, and what the Original
         Work is.  (They may limit the Derogation to only some of the
         Allowable Extra Provisions.)

  (iv)   The GPL'd Work is combined with another work (the Other
         Work) to make a `work as a whole', the Combined Work.

  (x)    The Other Work is licenced free of charge to third parties;
         under the terms of a licence henceforth known as the Other
         Licence.

  (xi)   The Other Licence is Free.

  (v)    It would be an infringement of the copyright in the Other
         Work for you to distribute the Combined Work under the terms
         of the GNU GPL v2.

  (vi)   There is a Resulting Licence which is the GNU GPL v2 amended
         by the addition of Extra Provisions and the relevant
         conditions from this Licence Derogation, where

  (viii) the Extra Provisions are some or all of the Allowable Extra
         Provisions (see below), and

  (x)    the Extra Provisions are provisions of the Other Licence.


 (C) Permission:

  (i)    Provided that the the conditions in this Licence Derogation
         are met, you may distribute the Combined Work under the terms
         of the Resulting Licence.

  (ii)   When the Combined Work is distributed under the terms of the
         Resulting Licence, references to `this licence' in the text
         of the GPL v2 may be read as references to the Resulting
         Licence, or as references to the GPL v2, at your option.

 (D) Further Conditions:

  (i)    All parts of the Combined Work which are (identical to, parts
         of, or derived from) the GPL'd Work can be easily separated
         out from the Whole Work's source code to form once more a
         Re-separated Work.

  (ii)   The Re-separated Work is a version of the Original Work which
         is similar or superior in all respects (including
         completeness, functionality, quality etc.) to the Original
         Work.

  (iii)  The Re-separated Work is licensed to third parties under
         terms identical to those under which the GPL'd Work is
         licenced to those same third parties.

  (iv)   Copyright licences and notices which would appear to the
         reader to cover the Combined Work contain the following
         statement or an equivalent:
           Different parts of this software may be covered by
           different copying conditions.  See individual source code
           files or copyright statements for details.


 (E) The Allowable Extra Provision Kinds:

   (i)   In each of the following Kinds (`(1)' onwards), the nature of
         the Extra Provisions which are made Allowable, and the
         further conditions which must be satisfied (and which
         therefore form part of the Resulting Licence) are stated.

   (ii)  All of the paragraphs (`(i)' onwards) stated in each Kind
         must be satisfied, for Extra Provisions to be Allowable.

  (1) `Obnoxious advertising clause':
  
   (i)   The Extra Provisions are those of the form:
            All advertising materials mentioning features or use of
            this software must display the following acknowledgement:
              This product includes software developed by DEVELOPERS.
         and re-wordings with similar effect, where DEVELOPERS is a
         person or group associated with the development of the Other
         Work.

   (ii)  All advertising materials mentioning features or use of the
         Combined Work must display a similar acknowledgement for
         every Identifiable Author.

   (iii) All distributions of the Combined Work must contain a list of
         the Identifiable Authors.       

  (2) `Endorsement restriction':

   (i)   The Extra Provisions are ones which restrict the use of the 
         authors', copyright holders' and/or contributors' names for
         endorsement or promotion of products.

   (ii)  The endorsement restriction(s) must benefit all of the
         natural persons and organisations with an interest in the
         Whole Work, unless those people wish otherwise.

  (3) `Liability limitation':

   (i)   The Extra Provisions are ones which claim to exclude or limit
         in any way the liability, for malfunctions, failures etc. of
         the Whole Work or parts thereof, of any contributors,
         distributors, copyright holders, authors, etc. of the
         software.  Provisions which seek to deny warranties, even
         implied warranties, or which otherwise seek to limit similar 
         exposure(s) to risk(s), count.

   (ii)  The protections of the Extra Provisions must be extended to
         all of the authors and distributors of the Whole Work, unless
         those people wish otherwise.


  (4) `Pointless restatements':

   (i)   The Extra Provisions are ones which require distributions of
         the Whole Work to contain notices in source and/or binary
         distributions, and/or in the documentation and/or other
         materials provided with the distributions.

   (ii)  The required notices must be simple truths, or restatements
         of licence provisions which actually apply to the Combined
         Work.

   (iii) (The author of this Licence Derogation believes that
         `pointless restatement requirements' are compatible with the
         GPLv2, since they seem to fall under the heading of an
         `appropriate copyright notice and disclaimer of warranty',
         which is already required by the GPLv2.  However, this
         relaxation is provided in case of doubt.)


  (5) `Service provision - source code to users' (eg AGPL):

   (i)   The Extra Provisions apply only
        (a) when the Other Work or Combined Work is intended to
            interact with people (`Users') through a computer network,
            or
        (b) when the Other Work or Combined Work is executed on behalf
            of a third party (the `User'),
         (or when both (a) and (b) apply).

   (ii)  There exists a Sensible Publication Mechanism such that the
         Extra Provisions are satisfied when:
        (a) the Combined Work is made available free of charge to the
            public, by that Sensible Publication Mechanism, and
        (b) the existence and details of the Sensible Publication
            Mechanism are made known in appropriate ways to each
            User.

   (iii) A Sensible Publication Mechanism is a reasonable and
         convenient means for allowing members of the public
         (`Downloaders') to obtain the source code in machine-readable
         form.

   (iv)  A Sensible Publication Mechanism is not more onerous to
         provide than a public-facing World Wide Web server.


 (F) Additional definitions:

  (i)    A Free software licence is one which is approved both
        (a) as a Free Software licence by the Free Software
            Foundation, and
        (b) as an Open Source Licence by the Open Source Initiative.

  (ii)   A Combining Participant includes any person:
        (a) who makes a modification to the Other Work, which is
            now included in the Combined Work, with a view to the
            creation of any work which might be a Combined Work
            according to this Licence Derogation; or
        (b) who obtains the Other Work and GPL'd work separately and
            distributes the Combined Work.

  (iii)  An Identifiable Author is
        (a) a natural person
        (b) who contributed to the Combined Work (including without
            limitation as a work for hire)
        (c) whose identity or proper form of acknowledgement it
            reasonably practical to determine by inspection of the
            Authorship Documentation,
        (d) and who has not stated publicly that they do not wish such
            acknowledgements to be displayed.

  (iv)   The Authorship Documentation includes all copyright notices,
         authorship notices, credits files, change logs,
         acknowledgements, and similar documentation, in the source
         code for the Original Work, the GPL'd Work, the Other Work
         and the Combined Work.

  (v)    The Authorship Documentation also includes any communications
         received by a Combining Participant regarding authorship of
         any part of the Combined Work.





   (iv)  A Sensible Publication Mechanism does not require any
         Downloader to provide any identification or authorisation
         other than that inherently required by the underlying
         technical mechanisms.

   (v)   A Sensible Publication Mechanism is free of charge.

   (vi)  A Sensible Publication Mechanism does not make any efforts to
         trace, track, cross-reference, or otherwise gain information
         about Downloaders, other than the minimum data required for
         direct technical fault-finding; any data collected shall be
         used only for direct technical fault-finding.

   (vii) Where a Sensible Publication Mechanism involves
         implementation of a technical communications protocol, the
         Mechanism must permit the use by Downloaders of the widest
         feasible range of standards-compliant software.

   (vii) For example, for download via the public World Wide Web to
         satisfy this paragraph, the HTTP server must permit downloads
         from any IP address, and it may not have any access controls,
         cookies, reverse DNS requirements, registration forms, adult
         checks, authorisation codes, email confirmations, URL
         session-ids, browser restrictions, JavaScript, Java, Flash,
         and must use the most conservative possible HTML, and the
         webserver logs must contain the least possible information
         and be expired quickly.

DRAFT

, or to pay anyone any
         money.

   

which there is a
         Sensible Mechanism  can be 

(to the Other Work publicly and freely available.

          (a) (from `AGPL version 1')
               If the Program as you received it is intended to
               interact with users through a computer network and if,
               in the version you received, any user interacting with
               the Program was given the opportunity to request
               transmission to that user of the Program's complete
               source code, you must not remove that facility from
               your modified version of the Program or work based on
               the Program, and must offer an equivalent opportunity
               for all users interacting with your Program through a
               computer network to request immediate transmission by
               HTTP of the complete source code of your modified
               version or other derivative work.


DRAFT --- Ian Jackson 10.5.1999

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