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 . 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 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 Local variables: mode: text End: