WARNING: This document is made public for archival and historical purposes only. Not all of the information is current, and accuracy cannot be guaranteed.
WARNING: This document is made public for archival and historical purposes only. Not all of the information is current, and accuracy cannot be guaranteed.
GPLv2 §4 is GPLv2’s termination clause. Upon first examination, it seems strange that a license with the goal of defending users’ and programmers’ freedoms for perpetuity in an irrevocable way would have such a clause. However, upon further examination, the difference between irrevocability and this termination clause becomes clear. (See 7.4 for expanded discussion of GPLv2 irrevocability.)
The GPL is irrevocable in the sense that once a copyright holder grants rights for someone to copy, modify and redistribute the software under terms of the GPL, they cannot later revoke that grant. Since the GPL has no provision allowing the copyright holder to take such a prerogative, the license is granted as long as the copyright remains in effect.1 The copyright holders have the right to relicense the same work under different licenses (see Section 12.2 of this tutorial), or to stop distributing the GPLv2’d version (assuming GPLv2 §3(b) was never used), but they may not revoke the rights under GPLv2 already granted.
In fact, when an entity loses their right to copy, modify and distribute GPL’d software, it is because of their own actions, not that of the copyright holder. The copyright holder does not decide when GPLv2 §4 termination occurs (if ever); rather, the actions of the licensee determine that.
Under copyright law, the GPL has granted various rights and freedoms to the licensee to perform specific types of copying, modification, and redistribution. By default, all other types of copying, modification, and redistribution are prohibited. GPLv2 §4 says that if you undertake any of those other types (e.g., redistributing binary-only in violation of GPLv2 §3), then all rights under the license — even those otherwise permitted for those who have not violated — terminate automatically.
GPLv2 §4 makes GPLv2 enforceable. If licensees fail to adhere to the license, then they are stuck without any permission under to engage in activities covered by copyright law. They must completely cease and desist from all copying, modification and distribution of the GPL’d software.
At that point, violating licensees must gain the forgiveness of the copyright holders to have their rights restored. Alternatively, the violators could negotiate another agreement, separate from GPL, with the copyright holder. Both are common practice, although Chapter 13.3 explains further key differences between these two very different uses of GPL.
GPLv2 §5 brings us to perhaps the most fundamental misconception and common confusion about GPLv2. Because of the prevalence of proprietary software, most users, programmers, and lawyers alike tend to be more familiar with EULAs. EULAs are believed by their authors to be contracts, requiring formal agreement between the licensee and the software distributor to be valid. This has led to mechanisms like “shrink-wrap” and “click-wrap” as mechanisms to perform acceptance ceremonies with EULAs.
The GPL does not need contract law to “transfer rights.” Usually, no rights are transferred between parties. By contrast, the GPL is primarily a permission slip to undertake activities that would otherwise have been prohibited by copyright law. As such, GPL needs no acceptance ceremony; the licensee is not even required to accept the license.
However, without the GPL, the activities of copying, modifying and distributing the software would have otherwise been prohibited. So, the GPL says that you only accepted the license by undertaking activities that you would have otherwise been prohibited without your license under GPL. This is a certainly subtle point, and requires a mindset quite different from the contractual approach taken by EULA authors.
An interesting side benefit to GPLv2 §5 is that the bulk of users of Free Software are not required to accept the license. Undertaking fair and unregulated use of the work, for example, does not bind you to the GPL, since you are not engaging in activity that is otherwise controlled by copyright law. Only when you engage in those activities that might have an impact on the freedom of others does license acceptance occur, and the terms begin to bind you to fair and equitable sharing of the software. In other words, the GPL only kicks in when it needs to for the sake of freedom.
While GPL is by default a copyright license, it is certainly still possible to consider GPL as a contract as well. For example, some distributors chose to “wrap” their software in an acceptance ceremony to the GPL, and nothing in the GPL prohibits that use. Furthermore, the ruling in Jacobsen v. Katzer, 535 F.3d 1373, 1380 (Fed.Cir.2008) indicates that both copyright and contractual remedies may be sought by a copyright holder seeking to enforce a license designed to uphold software freedom.
A point that was glossed over in Section 7.1’s discussion of GPLv2 §4 was the irrevocable nature of the GPL. The GPLv2 is indeed irrevocable, and it is made so formally by GPLv2 §6.
The first sentence in GPLv2 §6 ensures that as software propagates down the distribution chain, that each licensor can pass along the license to each new licensee. Under GPLv2 §6, the act of distributing automatically grants a license from the original licensor to the next recipient. This creates a chain of grants that ensure that everyone in the distribution has rights under the GPLv2. In a mathematical sense, this bounds the bottom — making sure that future licensees get no fewer rights than the licensee before.
The second sentence of GPLv2 §6 does the opposite; it bounds from the top. It prohibits any licensor along the distribution chain from placing additional restrictions on the user. In other words, no additional requirements may trump the rights and freedoms given by GPLv2.
The final sentence of GPLv2 §6 makes it abundantly clear that no individual entity in the distribution chain is responsible for the compliance of any other. This is particularly important for noncommercial users who have passed along a source offer under GPLv2 §3(c), as they cannot be assured that the issuer of the offer will honor their GPLv2 §3 obligations.
In short, GPLv2 §6 says that your license for the software is your one and only copyright license allowing you to copy, modify and distribute the software.
GPLv2 §6 is GPLv2’s “automatic downstream licensing” provision2. Each time you redistribute a GPL’d program, the recipient automatically receives a license from each original licensor to copy, distribute or modify the program subject to the conditions of the license. The redistributor need not take any to ensure the downstream recipient’s acceptance of the license terms. This places every copyright holder in the chain of descent of the code in legal privity, or direct relationship, with every downstream redistributor. Two legal effects follow. First, downstream parties who remain in compliance have valid permissions for all actions (including modification and redistribution) even if their immediate upstream supplier of the software has been terminated for license violation3. Downstream’s licensed rights are not dependent on compliance of their upstream, because their licenses issue directly from the copyright holder. Second, automatic termination cannot be cured by obtaining additional copies from an alternate supplier: the license permissions emanate only from the original licensors, and if they have automatically terminated permission, no act by any intermediate license holder can restore those terminated rights4.
This section digresses briefly to examine the manner in which GPLv2§§ 4–6 interact together to assure that the license grant is irrevocable. There are two legal theories why a contributor cannot terminate their license grant. First is an argument that the text of the GPL prevents it; second is that a contributor would be estopped from succeeding on an infringement claim for continued use of the code even if it wasn’t removed.
The GPLv2 have several provisions that, when taken together, can be construed as an irrevocable license from each contributor. First, the GPLv2 says “by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License to do so, and all its terms and conditions for copying, distributing or modifying the Program or works based on it” (GPLv2§5, emphasis added). A contributor by definition is modifying the code and therefore has agreed to all the terms in the GPLv2, which includes the web of mechanisms in the GPLv2 that ensure the code can be used by all.
More specifically, the downstream license grant says “the recipient automatically receives a license from the original licensor to copy, distribute or modify the Program subject to these terms and conditions.” (GPLv2§6). So in this step, the contributor has granted a license to the downstream, on the condition that the downstream complies with the license terms.
That license granted to downstream is irrevocable, again provided that the downstream user complies with the license terms: “[P]arties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance” (GPLv2§4).
Thus, anyone downstream of the contributor (which is anyone using the contributor’s code), has an irrevocable license from the contributor. A contributor may claim to revoke their grant, and subsequently sue for copyright infringement, but a court would likely find the revocation was ineffective and the downstream user had a valid license defense to a claim of infringement.
Nevertheless, for purposes of argument, we will assume that for some reason the GPLv2 is not enforceable against the contributor5, or that the irrevocable license can be revoked6. In that case, the application of promissory estoppel will likely mean that the contributor still cannot enforce their copyright against downstream users.
“Promissory estoppel” is a legal theory that says, under some circumstances, a promise is enforceable against the promisee even after the promisee tries to renege on the promise. The test for how and when promissory estoppel applies differs from state to state, but generally where there is a “promise which the promisor should reasonably expect to induce action or forbearance on the part of the promisee or a third person and which does induce such action or forbearance is binding if injustice can be avoided only by enforcement of the promise.”7 Breaking it down, it is:
In this case, the promisor is the contributor. This should be an easy standard to meet in any widely used software.
Whether as a matter of a straightforward contractual obligation, or as a matter of promissory estoppel, a contributor’s attempt to revoke a copyright license grant and then enforce their copyright against a user is highly unlikely to succeed.
In essence, GPLv2 §7 is a verbosely worded way of saying for non-copyright systems what GPLv2 §6 says for copyright. If there exists any reason that a distributor knows of that would prohibit later licensees from exercising their full rights under GPL, then distribution is prohibited.
Originally, this was designed as the title of this section suggests — as a last ditch effort to make sure that freedom was upheld. However, in modern times, it has come to give much more. Now that the body of GPL’d software is so large, patent holders who would want to be distributors of GPL’d software have a tough choice. They must choose between avoiding distribution of GPL’d software that exercises the teachings of their patents, or grant a royalty-free, irrevocable, non-exclusive license to those patents. Many companies have chosen the latter.
Thus, GPLv2 §7 rarely gives software death by stopping its distribution. Instead, it is inspiring patent holders to share their patents in the same freedom-defending way that they share their copyrighted works.
GPLv2 §8 is rarely used by copyright holders. Its intention is that if a particular country, say Unfreedonia, grants particular patents or allows copyrighted interfaces (no country to our knowledge even permits those yet), that the GPLv2’d software can continue in free and unabated distribution in the countries where such controls do not exist.
As far as is currently known, GPLv2 §8 has very rarely been formally used by copyright holders. Admittedly, some have used GPLv2 §8 to explain various odd special topics of distribution (usually related in some way to GPLv2 §7). However, generally speaking, this section is not proven particularly useful in the more than two decades of GPLv2 history.
Meanwhile, despite many calls by the FSF (and others) for those licensors who explicitly use this section to come forward and explain their reasoning, no one ever did. Furthermore, research conducted during the GPLv3 drafting process found exactly one licensor who had invoked this section to add an explicit geographical distribution limitation, and the reasoning for that one invocation was not fitting with FSF’s intended spirit of GPLv2 §8. As such, GPLv2 §8 was not included at all in GPLv3.
1In the USA, due to unfortunate legislation, the length of copyright is nearly perpetual, even though the Constitution forbids perpetual copyright.
2This section was substantially expanded for clarity and detail in GPLv3 §10.
3 While this is legally true, as a practical matter, a failure of “complete, corresponding source” (CCS) provisioning by an upstream could make it effectively impossible for a downstream party to engage in a commercial redistribution pursuant to GPLv2 §3(a–b). (§ 18.2 in the Compliance Guide portion of this tutorial discussed related details.)
4While nearly all attorneys and copyleft theorists are in agreement on this point, German copyleft legal expert Till Jaeger vehemently disagrees. Jaeger’s position is as follows: under German copyright law, a new copy of GPL’d software is a “fresh” license under GPL, and if compliance continues from that point further, the violator’s permissions under copyright law are automatically restored, notwithstanding the strict termination provision in GPLv2 §4. However, in practice, this issue is only salient with regard to proprietary relicensing business models, since other copyright holders typically formally restore distributions rights once the only remaining compliance issue is “you lost copyright permission due to GPLv2 §4”. Therefore, the heated debates, which have raged between Jaeger and almost everyone else in the copyleft community for nearly a decade, regard an almost moot and wholly esoteric legal detail.
5For example, the argument has been made that there may be a failure of consideration on the part of the contributor. While Jacobsen v. Katzer, 535 F.3d 1373 (Fed. Cir. 2008) is accepted as holding that there is consideration received by the contributor in a FOSS license, the posture of the case was one where the contributor advocated for the theory, not against it. The author is not aware of any other decisions that have analyzed the question in any depth, so it perhaps could be challenged in the right factual situation.
6A contract without a definable duration can be terminated on reasonable notice. Great W. Distillery Prod. v. John A. Wathen Distillery Co., 10 Cal. 2d 442, 447, 74 P.2d 745, 747 (1937). The term nevertheless can be a term of indefinite length where its continuing effect is tied to the conduct of the parties. Id.
7Kajima/Ray Wilson v. Los Angeles Cty. Metro. Transp. Auth., 23 Cal. 4th 305, 310, 1 P.3d 63, 66 (2000), citing Restatement (Second) of Contracts §90(1) (1979).