| Author | Sun Microsystems,Oracle Corporation |
|---|---|
| Latest version | 1.1 |
| Publisher | Oracle Corporation |
| SPDX identifier | CDDL-1.1 CDDL-1.0 |
| Debian FSG compatible | Yes |
| FSFapproved | Yes (only 1.0)[1] |
| OSIapproved | Yes (only 1.0)[2] |
| GPL compatible | No[1] |
| Copyleft | Yes, file-level[1] |
| Linking from code with a different licence | Yes[1] |
TheCommon Development and Distribution License (CDDL) is afree and open-sourcesoftware license,[3] produced bySun Microsystems, based on theMozilla Public License (MPL). Files licensed under the CDDL can be combined with files licensed under other licenses, whether open source or proprietary.[2] In 2005 theOpen Source Initiative approved the license. TheFree Software Foundation (FSF) considers it afree software license, but one which isincompatible with theGNU General Public License (GPL).[1]
Derived from theMozilla Public License 1.1,[4] the CDDL tries to address some of the problems of the MPL.[5] Like the MPL, the CDDL is a weakcopyleft license in-betweenGPL license andBSD/MITpermissive licenses, requiring only source code files under CDDL to remain under CDDL.
Unlike strongcopyleft licenses like the GPL, mixing of CDDL licensed source code files with source code files under other licenses is permitted without relicensing. The resulting compiled software product ("binary") can be licensed and sold under a different license, as long as the source code is still available under CDDL, which should enable more commercial business cases, according to Sun.[5][6][7]
Like the MPL the CDDL includes a patent grant to the licensee from all contributors ("patent peace"). However, in section 2.1(d), the patent grant is lost if the code implementing a patented feature is modified.[8]
The previoussoftware license used bySun for itsopen source projects was theSun Public License (SPL), also derived from theMozilla Public License. The CDDL license is considered bySun (nowOracle) to beSPL version 2.[9]
The CDDL was developed by aSun Microsystems team (among themSolaris kernel engineer Andrew Tucker[10][11] and Claire Giordano[12]), based on theMPL version 1.1. On December 1, 2004 the CDDL was submitted for approval to theOpen Source Initiative[12] and was approved as anopen source license in mid January 2005.The second CDDL proposal, submitted in early January 2005, includes some corrections that prevent the CDDL from being in conflict with European Copyright law and to allow single developers to use the CDDL for their work.
In 2006, in the first draft of the OSI'slicense proliferation committee report, the CDDL is one of nine preferred licenses listed as popular, widely used, or with strong communities.[13]
While theFree Software Foundation (FSF) also considered the CDDL afree software license, they saw someincompatibilities with theirGNU General Public License (GPL).[1]
The question of whether and when both licenses areincompatible sparked debates in the free software domain in 2004 to 2006.[14][15] For instance, the FSF considered the CDDL incompatible to their GPL license, without going into detail until 2016.[16]
CDDL is one of severalOpen Source Licenses which areincompatible with GPL.This characteristic was inherited from the MPL 1.1 (fixed with the MPL 2.0 according to the FSF[1]) and results from a complex interaction of several clauses;[14][17] the root of the problem being GPLvirality, similar to other cases of GPL incompatibility.[18] Some people argue that Sun (or the Sun engineer) as creator of the license made the CDDL intentionally GPL incompatible.[14] According toDanese Cooper one of the reasons for basing the CDDL on the Mozilla license was that the Mozilla license isGPL-incompatible. Cooper stated, at the 6th annualDebian conference, that the engineers who had written the Solaris kernel requested that the license of OpenSolaris be GPL-incompatible.[19]
Mozilla was selected partially because it is GPL incompatible. That was part of the design when they released OpenSolaris. ... the engineers who wrote Solaris ... had some biases about how it should be released, and you have to respect that.
Simon Phipps (Sun's Chief Open Source Officer at the time), who had introduced Cooper as "the one who actually wrote the CDDL",[20] did not immediately comment, but later in the same video, he says, referring back to the license issue, "I actually disagree with Danese to some degree",[21] while describing the strong preference among the engineers who wrote the code for a BSD-like license, which was in conflict with Sun's preference for somethingcopyleft, and that waiting for legal clearance to release some parts of the code under the then unreleased GNU GPL v3 would have taken several years, and would probably also have involved mass resignations from engineers (unhappy with either the delay, the GPL, or both—this is not clear from the video).
Later, in September 2006, Phipps rejected Cooper's assertion in even stronger terms.[22] Similarly,Bryan Cantrill, who was at Sun at that time and involved in the release of CDDL licensed software stated in 2015 that he and his colleagues expected in 2006 the fast emergence of CDDL licensed software into the Linux ecosystem and the CDDL being not an obstacle.[23]
The GPL compatibility question was also the source of a controversy behind a partial relicensing ofcdrtools to the CDDL which had been previously all GPL. In 2006, theDebian project declared the cdrtools legally undistributable because thebuild system was licensed under the CDDL.[24]
The author, Jörg Schilling, claimed thatsmake is an independent project and does not violate theGPLv3.[25] Schilling also argued that even though the GPL requires all scripts required to build the work to be licensed freely, they do not necessarily have to be under the GPL.[26][27][page needed] Thus not causing an incompatibility thatviolates the license.
He also argued that in "combined works" (in contrast to "derived works") GPL and CDDL licensed code is compatible.[28][29]
Red Hat's attorneys have prevented cdrtools from being inFedora orRed Hat Enterprise Linux, arguing that Schilling has an "unorthodox" view of copyright law that isn't shared by their legal counsel or the Free Software Foundation.[30]
In 2015, the CDDL to GPL compatibility question reemerged whenUbuntu announced inclusion ofOpenZFS by default.[31]
In 2016 Ubuntu announced that a legal review resulted in the conclusion that it is legally acceptable to use ZFS as binarykernel module in Linux. (As opposed to building it into the kernel image itself.)[32]
Others followed Ubuntu's conclusion, for instance James E. J. Bottomley argued there cannot be "a convincing theory of harm" developed, making it impossible to bring the case to court.[33]
Eben Moglen, co-author of theGPLv3 and founder of theSFLC, argued that while the letter of the GPL might be violated, the spirit of both licenses is unharmed, which would be the relevant aspect in court.[34]
The SFLC mentioned also that a precedent exists with theAndrew File System's kernel module, which is not considered a derivative work of the kernel by the kernel developers.[35][36]
On the other hand,Bradley M. Kuhn and attorneyKaren M. Sandler from theSoftware Freedom Conservancy[37] argued that Ubuntu would violate both licenses, as a binary ZFS module would be a derivative work of the kernel.[38] In April 2016, theUbuntu 16.04 LTS release included the CDDL-licensedZFS on Linux.[citation needed]
Example projects released under CDDL:
We have drafted a new open source license ...
The SPL was based on the Mozilla license - as CDDL is as well. [..] One way to think of the CDDL is as a cleaned-up version of the Mozilla license - anyone can reuse it as-is. It's the SPL version 2.0.
A common misconception is about CDDL and GPL incompatibility. (Incompatibility in the sense: to combine two source files, one under GPL and another under CDDL, to create a common executable.) GPL is incompatible with most licenses like Mozilla Public License, Apache, and CDDL. GPL wants you erase those licenses and use GPL in that place, where as these licenses do not permit erasing them. Hence the incompatibility deadlock.
Mozilla was selected partially because it is GPL incompatible. That was part of the design when they released OpenSolaris. ... the engineers who wrote Solaris ... had some biases about how it should be released, and you have to respect that(alternate URL, see 27:27 through 28:24)
...we have got Danese Cooper in the room, and she is the one who actually wrote the CDDL...
I actually disagree with Danese to some degree...
Nonetheless she is wrong to characterise the opinion of the Solaris engineering team in the way she does. She is speaking this way because she lost an argument inside Sun, not because her view is representative of the views of Sun or its staff in the way she claims. She, along with many actual engineers, was an advocate of using GPL for OpenSolaris but the need to release rather than wait for one of {GPL v3, Mozilla license revision, encumbrance removal} meant that this was not possible. I am still furious with her for the statement she made at DebConf, which was spiteful and an obstacle to a united FOSS movement.
Question: Was the CDDL designed to prevent Sun technologies from entering Linux? - BC: Great question, and the answer was that we didn't know -- but the expectation was that it would be ported to Linux relatively quickly. I remember vividly standing over a terminal with a bunch of people as we actually launched OpenSolaris (like, clicked carriage return on making the DTrace code live -- which was the first in the chute), and the Sun Legal guy and I were chatting. We were both wondering if DTrace was going to show up in Linux in a month or if it would take two years. But that was the range of guesses: neither of us believed that the Linux community themselves would hold up CDDL as an obstacle, and certainly if you told me that a decade later, DTrace wouldn't be in Linux because of licensingFUD, I wouldn't have believed you. Of course, in hindsight, it all seems so clear:NIH is enormously powerful, and we were fools for discounting it.
Laut Aussagen von Jörg Schilling sind die Lizenzen durchaus miteinander kompatibel. Die Regeln werden oftmals falsch ausgelegt. Die Aussagen der FSF-Verantwortlichen seien oft widersprüchlich und in sich nicht schlüssig.
Historically, there's been things like the original Andrew filesystem module: a standard filesystem that really wasn't written for Linux in the first place, and just implements a UNIX filesystem. Is that derived just because it got ported to Linux that had a reasonably similar VFS interface to what other UNIXes did? ... Personally, I think that case wasn't a derived work, and I was willing to tell the AFS guys so.
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