Reciprocity under the GNU General Public Licenses


  • Pessi Honkasalo



Forming the Question The GNU General Public Licenses are the most widely used open source software licenses worldwide. According to a license breakdown statistics from, one of the largest software repositories, some 70 percent of applications that are released under an open source license carry that of GNU1. Here, the reference to the GNU General Public Licenses is made in plural, for there are in all three GNU software licenses: a) the GNU General Public License (GPL), b) the GNU Lesser General Public License (LGPL) and c) the GNU Affero General Public License (AGPL)2. Of these, the GPL is far and away the most popular. The prevalence of the LGPL is approximately one tenth thereof, and the latest entrant, AGPL, is still rather marginal, albeit increasingly used latterly.3 Each of the licenses has, however, its intended use and, in that regard, particular contractual provisions and effects, which naturally influence the potential penetration. Such elements form the very research problem of this study, so that at this stage it suffices to say that, on average, the GPL is used for programs, the LGPL for libraries and the AGPL for software that is commonly run over a network. Notwithstanding the fact that most projects licensed under the GNU software licenses are unquestionably of minor importance or intended for a limited audience, the great social significance of these licenses stems from the other fact that some of the most widely used computer software is GNU-licensed, as well. Examples of such programs include, among others, the Linux kernel, the GCC compiler collection, MySQL database server, Perl programming language, productivity suite, Java development kit, Samba file and print services, Qt development framework, iptables filter control tool, the CVS concurrent versioning system and Launchpad code hosting platform, which are all licensed under a GNU software license4. Many factors can drive a decision about technology architecture, information management, systems integration or software licensing in general. History, legacy systems, internal politics and the location of key people within an organisation may all be relevant, as well as other commercial motives, such as cost considerations and offerings of competing vendors. What tends to be on a lower level of priority, if indeed is properly considered at all, is the legal or regulatory impact of such a decision.5 However, since various contractual restraints contained in proprietary and open source licenses, respectively, may at a later time be proven to mean a significant effect on the contemplated use or even the dilution of the whole investment, judicial risk analysis ought to constitute an essential part of the planning work of a licensing strategy. Now, therefore, the purpose of this work is to interpret the reciprocity clauses included in the GNU software licenses, viz. which obligations they impose on the licensee and what sort of activity triggers such commitments. Looking at prior studies, one can find many general statements in the literature that characterise the GPL as possessing something called the ‘viral effect’6, the LGPL as being ‘persistent’7 and the AGPL as offering a plug for the ‘application service provider (ASP) loophole’8 in the ordinary GPL. However, the more precise meaning of such effects and the demarcation between various forms of combinations and modifications—as well as defining which acts constitute derivatives of functional relevance with regard to reciprocally licensed software—have been subject to unfortunately diminutive analysis in our jurisdiction9. My aim is to systematise the mechanisms of reciprocity under the doctrine of GNU software licenses. First, I seek to offer, from the legal point of view, the intellectual readiness for making strategic licensing decisions in relation to the GPL and its derivatives for undertakings that are directly or indirectly conducting business in the computing industry. It is fundamental for developers to appreciate how the licenses affect the extent to which they can adapt the licensed software, and under what restrictions. Nevertheless, secondly, the factual audience is much wider. According to the statistics from a recent survey, more than half of the enterprises are using open source applications in their organisations today, and an additional ten percent plan to do so during this year10. Further, by 2012, research firm Gartner, Inc. believes that 80 percent of all commercial software applications will include open source components11. Inasmuch as the GNU software licenses hold the lion’s share of the open source market, it is highly probable that one wishes to be conscious of one’s risk position in such arrangements to eschew being legally exposed for violations of the license requirements.