GNU General Public License
The GNU General Public License or better known by its name in English GNU General Public License (or simply its acronym in English GNU GPL) is a copyright license widely used in the world of free and open source software, and guarantees end users (individuals, organizations, companies) the freedom to use, study, share (copy) and modify the software. Its purpose is twofold: to declare that the software covered by this license is free, and to protect it (through a practice known as copyleft) from appropriation attempts that restrict those freedoms to new users each time the work is distributed, modified or expanded. This license was originally created by Richard Stallman, founder of the Free Software Foundation (FSF) for the GNU project.
The Free Software Foundation makes the GPL available to anyone who wants to protect the rights of its end users (to use, share, study, and modify), and grant to the beneficiaries of a computer program or other type of work is the definition of free software rights. The GPL is distinguished from public domain or other free software licenses known as permissive by emphasizing copyleft, or only allowing copies and derivatives of a work under the GPL perpetuate the same license.
Most GNU software is copyleft, but not all; however, all GNU software must be free software.
Some of the GNU software was written by the Free Software Foundation team, but most of it came from a few volunteers. Some of that software is copyrighted by the Free Software Foundation, some is under the copyright of their authors.
David A. Wheeler argues that the copyleft provided by the GPL was crucial to the success of Linux-based systems, giving programmers who contributed to the kernel the assurance that their work was it would benefit the whole world and remain free, instead of being exploited by software companies that would not have to give anything back to the community.
Users or companies that distribute their works under the GPL, can charge or distribute them for free. This distinguishes the GPL from software licenses that prohibit commercial distribution. The FSF argues that the commercial distribution of the software (including redistribution) should not be restricted, and in that sense the GPL explicitly states that the works covered by this license are They can sell at any price.
History
The GPL was created by Richard Stallman in 1989 to protect programs released as part of the GNU project. The original GPL was based on the unification of similar licenses used in earlier versions of GNU Emacs, GNU Debugger, and the GNU C Compiler. These licenses contained similar provisions to the current GPL, but were specific to each program, making them incompatible, despite to be the same license. Stallman's goal was to produce a license that could be applied to any project, making it possible to use them in many code-sharing projects.
The second part of this license, version 2, was released in 1991. Over the next 15 years, members of the FOSS community became concerned with problems in GPLv2 that allowed GPL software to be exploited with intent contrary to the license. These issues included tivoization, which is the inclusion of GPL software on hardware that will refuse to run modified versions of your software, compatibility issues such as with the Affero General Public License; and patent disputes between Microsoft and free and open source vendors, which were seen as an attempt to use patents as a weapon against the FOSS community.
Historically, the GPL family of licenses has been one of the most popular software licenses in the free software domain. The third version of this license (GNU GPLv3) was developed to try to solve these problems and was officially released on July 25, 2007. This is the first copyleft license for general use, which means that derivative works can only be distributed under the terms of the same license.
Version 1
Version 1 of the GNU GPL, released on February 25, 1989, prevented what were the two main ways software distributors restricted the freedoms defined by free software. The first problem was that the distributors published only the binary files, functional and executable, but not understandable or modifiable by humans. To prevent this, the GPLv1 established that any free software provider, in addition to distributing the binary file, must also release understandable source code and that could be modified by human beings, under the same license (sections 3a and 3b of the license)..
The second problem was that distributors could add additional restrictions, either by adding restrictions to the license or by combining the software with software that had other restrictions in their distribution. If this was done, then the union of the two sets of constraints would be applied to the combined work and then unacceptable constraints could be added. To prevent this, GPLv1 mandated that modified versions as a whole had to be distributed under the GPLv1 terms (sections 2b and 4 of the license). Therefore, software distributed under GPLv1 can be combined with software under more permissive terms and not with software with more restrictive licenses, which would conflict with the requirement that all software must be distributed under the terms of the GPLv1.
Version 2
According to Richard Stallman, the biggest change in GPLv2 was the "Liberty or Death" clause, as he calls it in section 7 of that document. This section says that if someone imposes restrictions that you prohibit distributing GPL code in a way that affects users' freedoms (for example, if a law requires that person to distribute the software only in binary), that person may not distribute GPL software. The hope is that this will make it less tempting for companies to resort to patent threats to demand remuneration from free software developers.
In 1991 it became clear that a less restrictive license would be strategically useful for the C library and for software libraries that essentially did the work that other existing commercial libraries did. When GPL version 2 was released In June 1991, a second Library General Public License was introduced at the same time and numbered version 2 to denote that the two are complementary. The version numbers diverged in 1999 when version 2.1 of the LGPL was released, it was renamed the GNU Lesser General Public License to reflect its place in this philosophy.
Version 3
In late 2005, the Free Software Foundation (FSF) announced that it was working on version 3 of the GPL (GPLv3). On January 16, 2006, the first draft of GPLv3 was published, and public consultation began. The public consultation was originally planned to last from nine to fifteen months, but was eventually extended to eighteen months, during which four drafts were published. The official GPLv3 was released by the FSF on June 29, 2007.
According to Stallman the most important changes occurred in the field of software patents, the compatibility of free software licenses, the definition of source code, and hardware restrictions regarding hardware modifications. Other changes are related to internationalization, how license violations are handled, and how additional permissions can be granted by the copyright holder. He also adds provisions to strip DRM of its legal value, so it's possible to break DRM in GPL software without breaking laws like the DMCA.
The public consultation process was coordinated by the Free Software Foundation with assistance from the Software Freedom Law Center, Free Software Foundation Europe, and other free software groups. Public comments were collected through the gplv3.fsf.org portal.
During the public consultation process, 962 comments were submitted for the first draft. Finally, at the end of the process, the figure of 2,636 comments was reached.
The third draft was released on March 28, 2007. This draft includes mechanisms to avoid patent-related settlements, such as the controversial settlement between Microsoft and Novell, and restricts anti-tivization clauses to a legal definition of a "user" or "consumer product". It also removes the "Geographical limitations" section, the probable deletion of which had been announced at the launch of the public consultation.
The fourth draft, which was the last, was released on May 31, 2007. It introduced compatibility with the Apache Licenses, clarified the role of third-party contractors, and makes an exception to avoid problems caused by the agreement Microsoft-Novell, stating in paragraph 6 of Section 11 as follows:
You may not distribute a repaired work if you are part of an agreement with a third party that is in the software distribution business, under which you make payment to the third party on the basis of the extension of the work distribution activity, and under which you grant it, to any of the parties that would receive the repaired work, a discriminatory patent license
The goal of this is to make these kinds of deals ineffective. The license is intended to require Microsoft to extend patent licenses to grant Novell customers the use of GPLv3, which is possible only if Microsoft is a legal distributor of the software under GPLv3.
Some high-level Linux kernel developers commented and made public statements to the media about their objections to drafts 1 and 2.
Terms and Conditions
The GPL terms and conditions must be made available to anyone who receives a copy of the work to which this license has been applied. Any license to which those terms apply gives permission to make modifications to a work, to make copies, and to distribute it or to distribute any of its derivative versions. With this license, it is allowed to charge for the distribution of each copy, or not to charge at all. This last point distinguishes GPL licenses from software licenses that prohibit commercial distribution. The FSF argues that free software should have no room for commercial restrictions, and works under these types of licenses can be sold at any price.
The GPL further states that a distributor may not impose "restrictions on the rights granted by the GPL". It prohibits activities such as distributing the software under a confidentiality agreement or contract. Distributors under the GPL also grant a license to any of their software patents, for use in GPL software.
The fourth section of version 2 of the license and the seventeenth section of version 3 require that programs distributed as precompiled binaries be accompanied by a copy of the source code, a written offer to distribute the source code through the same mechanism as the pre-compiled binary, or a written offer to obtain the source code of the binary received under the GPL. The second section of version 2 and the fifth section of version 3 also state that you must provide "to all recipients a copy of this License together with the Program". Version 3 of the license allows the source code to be made available on different platforms in compliance with the seventh section. These include downloading source code from an adjacent network server or obtaining it via peer-to-peer, as long as the compiled code is available and there are "clear instructions" on where to find the source code..
The FSF does not allow the application of copyrights to a work licensed under the GPL, unless the author explicitly applies them (this happens rarely with the exception of programs that are part of the GNU project). Only individual rights holders have the authority to sue a license violation when it occurs.
Copyleft
The distribution rights granted by the GPL for modified versions of the work are not unconditional. When someone distributes under the GPL by adding their own modifications to the work, the requirements for distributing the entire work cannot be higher than the requirements that are in the GPL.
This requirement is known as copyleft. It reaches its true potential in the case of software copyrights. If a GPL work is copyrighted, you will not have the right to distribute this work, make modifications (except for your own use). By applying a GPL to a work, the rights in the work are protected by copyright law. And if instead, if you distribute copies of the work (licensed under the GPL) without abiding by the terms of the GPL (for example, by keeping the source code secret), you can be sued by the original copyright author. Author.
Copyleft therefore uses copyright law to achieve the opposite of its usual purpose: instead of imposing restrictions, it grants rights, in such a way as to guarantee that the rights cannot be subsequently taken away. or restricted. It also ensures that if unlimited redistribution rights are not granted or any legal failure occurs you are under the protection of the law.
Many distributors of programs under the GPL package the source code with the executable. An alternative that is copyleft compliant is to provide a written offer to distribute the source code on a physical medium (such as a CD) on demand. In practice, many programs under the GPL are distributed over the Internet, and the code is hosted on FTP, HTTP, etc. servers.
Copyleft only applies when it comes to redistributing the program. According to its bases, it is allowed to make the modifications made private, without obligation to disclose the modifications as long as this software is for your own use (it is not redistributed).
There was some debate as to whether it was a violation of the GPL to release source code in both obfuscated form and deliberately complex to understand. The general consensus was that while unethical, it was not considered rape. The matter was clarified when the license was amended to require that the "preferred" version of the source code had to be made available.
Licensing and contractual issues
GPL was designed to be more about a license than a contract. In some jurisdictions, the legal distinction between a license and a contract is very important: contracts are enforceable by contract law, while licenses are apply under copyright law. However, this distinction is not useful in the various jurisdictions where there are no differences between contracts and licenses, such as civil law systems.
Those who do not accept the GPL's terms and conditions are not allowed under copyright law to copy or distribute GPL software or derivative works. However, if you do not redistribute the program, you are free to use the software in your organization at your leisure, and these works (including programs) built under this use are not required to be licensed under this license.
Copyright Owners
The text that makes up the GPL is itself copyrighted and is the property of the FSF. However, the FSF does not own the copyright in a work released under the GPL, unless the author explicitly assigns the copyright to the FSF (which rarely happens except for programs that are part of the GNU project).). Only individual rights holders have the authority to sue a license violation when it occurs.
The FSF allows the public to create new licenses based on the GPL, as long as the derived licenses do not use the GPL without permission. This is not recommended, as such a license may be incompatible with the GPL. Other licenses created by the GNU project include the GNU Lesser General Public License and the GNU Free Documentation License.
Compatibility and multiple licenses
Code licensed under multiple licenses may be combined with GPL-licensed programs without conflict, as long as the combination of restrictions on the work as a whole does not place any additional restrictions beyond what is permitted by the GPL. In addition to the regular terms of the GPL, there are additional restrictions and permissions that may apply:
- If you want to combine code under different versions of GPL, you can do if the code with the older version of GPL includes the “any later version”.
- Code under LGPL can be linked to any other code, no matter which license has that code. Code under LGPLv2 without the statement “any later version” can be relicensed if the work is fully licensed with a GPLv2 or a GPLv3.
The FSF maintains a list of GPL-compatible free software licenses with many of the most common free software licences, such as the original MIT/X license and the BSD license (in its current three-clause form) and the Artistic 2.0 license.
David A. Wheeler has advocated for free/open source software developers to use only GPL-compliant licenses, because doing otherwise makes it more difficult for others to participate in and contribute to the code. As a specific example of Incompatibility, Sun Microsystems' ZFS cannot be included in the GPL of the Linux kernel, because it is under a GPL-incompatible CDDL. Also, ZFS is protected by patents, so independent distribution developed by a GPL implementation would require permission from Oracle.
Several companies use multiple licenses to distribute a GPL version and sell a proprietary one to other companies that want to combine the bundled code with proprietary code, using dynamic linking or not. Examples of these companies include MySQL AB, Digia PLC (Qt framework, pre-2011 Nokia), Red Hat (Cygwin), and RiverBank Computing (PyQt). Other companies, such as the Mozilla Foundation (some of its products include the Mozilla Application Suite, Mozilla Thunderbird, and Mozilla Firefox), use multiple licenses to distribute versions under the GPL and other open source licenses.
Legal validity
The GPL, being a document that grants certain rights to the user, assumes the form of a contract, which is why it is usually called a license agreement or license agreement. In Anglo-Saxon countries there is a distinction doctrine between licenses and contracts, but this does not occur in countries with a civil or continental tradition. As a contract, the GPL must meet the legal requirements for contract formation in each jurisdiction.
The license has been recognized, among others, by courts in Germany, particularly in the case of a judgment in a Munich court, which positively indicates its validity in civil law jurisdictions.
Adoption
Software under the GPL can be applied for all purposes, including commercial purposes and even as a proprietary software creation tool. In purely proprietary (or internal) use, with no sales or distribution involved, the software may be modified without releasing the source code, but otherwise the source code and any changes made to it must be made available to users, as in In this case, the user's rights are protected by copyleft. In this way, applications installed on prominent operating systems under the GPL such as Linux and also the GNU Compiler Collection, do not need to be licensed under the GPL or distributed with its source code available since the licenses do not depend on the platform. For example, if a program consists entirely of original code, or if it is combined with non-copylefted software, it does not need to be licensed under the GPL or distributed with its source code. available. Only if a program uses GPL code snippets (and the program is distributed) should the source code in its entirety be made available, under the same license. The other GNU license, LGPL (GNU Lesser General Public License) was created to have less restrictive rights than GPL, so in this case in a program that uses LGPL code snippets, you don't need to release the original code. Some other free software programs (as a prominent example is MySQL) are dual-licensed under various licenses, often with one of the certificates being the GPL.
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