- The GPL Bargain
- Copyleft and Reciprocity
- Policy Objectives
- The Preamble to the GPL
- GPL as Template
- The GPL Applies to Programs
- Linking to GPL Software
- Copyright Law and Linking
- The LGPL Alternative
- GPL Grant of License
- Access to Source Code
- "At No Charge"
- Other Obligations in the GPL
- The GPL and Patents
- Accepting the GPL
Accepting the GPL
Under contract law, a contract is not properly formed unless the parties to the contract manifest their assent to being bound by it. Such assent is traditionally manifested by signatures on a license agreement, a technique that is not appropriate for mass-marketed software distributed at retail stores or over the Internet.
For software downloaded from the Internet, distributors generally require a click-wrap form of assent. Before they can download the software, prospective licensees are presented with the license and are given a chance to "Click to Agree." Only those who manifest their assent by clicking are allowed to download the software. Courts have also blessed this procedure under contract law.
For retail store purchases, distributors often use shrink-wrap agreements. A license is placed in the package along with the software. By careful packaging (usually in a shrink-wrap plastic), licensors can ensure that prospective licensees have an opportunity to review the license agreement before they gain access to the copy of the software they have purchased. By proceeding to open the software, licensees are presumed to have seen and agreed to the license. Opening the inner software package is deemed to be an appropriate manifestation of assent. Licensees who don't assent to the license have the opportunity to return the copy of software, unopened, for a full refund of their purchase price. Courts have generally blessed this procedure as satisfying the manifestation of assent requirements of contract law.
Some software implements a click-wrap procedure that occurs as the copy of software is actually installed on a computer rather than when it is purchased. Regardless of when the assent is requested, any purchaser of a copy who does not assent must be given an opportunity to return the copy for a full refund.
Courts don't generally care whether prospective licensees actually read the license agreements as long as there is a reasonable opportunity to do so, and as long as their intent to assent is manifested.
Of course, since most consumers don't actually read license agreements, and since most license agreements are complicated legal documents with largely unintelligible legal language, courts will also protect consumers from being surprised by unfair or unexpected provisions, even if they have manifested their assent. For now, I assume that most people reading this book accept that open source licensesand the Open Source Principles upon which they are basedare fair.
The GPL relies on an entirely different set of legal principles, based on copyright law rather than contract law, to ensure that the license terms are accepted. It does not requireindeed its authors seek to prevent attempts to obtaina manifestation of assent to GPL license terms. The GPL license acceptance provision reads as follows:
You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, 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. (GPL section 5.)
Copyright law says that an author has exclusive rights to make copies of, to modify, or to distribute copyrighted software. Nobody can make a copy without a license from the author to do so. The mere exercise of someone else's exclusive rights without a license is an illegal copyright infringement. It is not necessary to prove that a defendant intended to infringe.
If you modify and distribute software without a license, the GPL suggests, you are presumed to know that your actions are illegal and, even if you don't know that you're breaking the law, the copyright law still makes you a copyright infringer. Don't do it, or you will expose yourself to potentially substantial penalties under the copyright law. (Possible penalties for copyright infringement include injunctions, the impounding and destruction of infringing articles, actual damages and profits, statutory damages, costs, and attorneys' fees.)
While this GPL reliance entirely on copyright law for license enforcement is legally sound, it has two shortcomings.
Only a copyright owner, not a distributor under a nonexclusive license, has standing to sue to enforce the GPL copyright license. On the other hand, if a contract is formed through a manifestation of assent, then contract law allows the distributor to enforce a license even if he or she doesn't own the copyrights in the underlying works. This means that if you use the GPL to distribute software but you don't own the copyrights to parts of that software, you can't sue under copyright law to protect those parts from infringement even if they were copied from your distribution. If you can prove that the licensee assented to a contract, however, you can protect your version of the entire work, and its component parts, against license violations.
At least in the United States, copyright disputes are heard only in federal court. Contract claims, on the other hand, can be heard in state and local courts, or in federal court if the amount in dispute is large enough and if the parties are not in the same state. If you use the GPL, you are limiting your litigation options to federal court.
If you are an open source licensor, I encourage you to obtain a proper manifestation of assent to your open source software licenses so that your enforcement options match your business strategies. If you want the option to pursue contract litigation and obtain contract law remedies, you probably don't want to use the GPL.
All open source licenses rely, at heart, upon the copyright law, as the GPL says in its section 5. But then, once a license is granted, that license may be interpreted under contract law provisions. Open source licenses should be clean, well-written contracts, or they may not be enforced by the courts.
This is the direction taken by all the licenses in the rest of this book. The GPL is the only license whose authors insist that it be treated as a bare copyright license but not a contract.