Google's use of the Linux kernel in Android may violate GPL's “copyleft” provisions, say several open source software legal experts. A successful lawsuit against Google on the issue — specifically related to the Bionic library that links Linux with Android's other components — could require the costly and time-consuming switch to the GPL'd Glibc library, one analyst suggests.

Discussions circulating among legal experts about the possible violation of the GPLv2 open source license in Android's use of Linux began with a Feb. 22 blog posting in IPinfoblog.com by law professor Raymond Nimmer. In the posting, Nimmer raised the question of whether Google violated the copyleft provisions of GPLv.2 in its use of certain Linux header files in Android.

According to Nimmer, Google's Android project uses a script to "cleanse" Linux core header files, removing comments as well as some code. Google then adds comments asserting that the resulting files contain no copyrighted material from Linux.

Google distributes Android generally under an Apache license "which is less demanding as a copyleft matter on Google and on resellers than GPL v.2," writes Nimmer. As a copyleft license, GPLv2 lets developers copy and modify Linux code freely, but stipulates that any modified code and works "based on'" it must be made freely available to all. This is intended to keep companies from using GPLv2-licensed code to make private and proprietary software.

"For there to be no expression remaining, however, what must have been removed is not only the human readable text, but also the expressive features involved in the structure of the header files," continues Nimmer. "This seems difficult to achieve since the goal was to borrow the effectiveness of the Linux system at least in part."

Nimmer says he is unsure whether Google was in actual violation of GPLv2's copyleft requirements, but notes the problem as a good law-school example of the challenge in determining when a software system is "based on" another program.

Naughton: a legal quandary for Android app developers

On Mar. 16, Brown Rudnick partner Edward J. Naughton went further, writing in the Huffington Post that the way that Google used the Linux header files "creates a legal quandary for manufacturers of Android devices", as well as for "many developers writing code and applications for those devices."

To enable software developers who want to use Android code in commercial and proprietary apps, while keeping their code-based secret from competitors, Google chose to license Android under the more business-friendly Apache Software License, explains Naughton. Yet, with the GPLv2'd Linux code lurking at the core of the Apache-licensed code, a conflict can occur when this happens.

At the heart of the potential violation, continues Naughton, is the Bionic Library, a C Library used by Android app developers who need to access the core functions of the Linux kernel.

"Google essentially copied hundreds of files of Linux code that were never meant to be used as is by application developers," writes Naughton. Google then "cleaned" those files using "a non-standard and questionable technical process, and then declared that the code was no longer subject to the GPLv2," he continues.

Google's intent was to let app developers use the Bionic library without becoming subject to copyleft restrictions. However, Naughton says he has "serious doubts" this approach is acceptable under U.S. copyright law, and says it represents a "significant gamble" for Google, at the risk of bring down the Android community with it.

If someone sues over the issue and Google is proven wrong, many Android developers and device manufacturers might be proven to have violated U.S. copyright law, he alleges. If Google is proven right, on the other hand, it will demonstrate that "Google has found a way to take Linux away from the open source community and privatize it," concludes Naughton. "Perhaps the community believes it can rely on Google to 'do no evil' with that kind of power, but can it rely on others to be so magnanimous?"

Mueller: More serious than Oracle lawsuit?

Open source legal expert and NoSoftwarePatents campaign founder Florian Mueller weighed in on the issue on Mar. 17, responding to the Nimmer and Naughton blogs by claiming that the problem may be even more serious than suggested. By copying "2.5 megabytes of code from more than 700 Linux kernel header files with a homemade program that drops source code comments and some other elements," and then claiming the information is not copyrightable, Google appears to have seriously violated GPLv2 copyleft restrictions, claims Mueller.

If Google is proven wrong, "many popular third-party closed-source components such as the Angry Birds game and the Adobe Flash Player — would actually have to be published under the GPL," writes Mueller. "A fully GPL'd Android would completely run counter to Google's Android strategy. Everyone would be free to use, modify and redistribute all of the affected software."

As a result, he adds, developers of commercial Android apps would lose their revenue opportunities, and it would be more difficult for device manufacturers to differentiate their products, leading to reduced prices and margins.

To avoid this potential "collapse of the Android ecosystem," Google may have to replace the Bionic library with a GPL'd library. This would pretty much narrow it down to Glibc (GNU C library), which is commonly used in open source projects such as MeeGo and WebOS. Yet, the transition would require thousands of Android components to be rewritten and rebuilt by Google and third parties, while leading to further compatibility issues with legacy Android versions, he adds.

Mueller goes on to offer a more detailed legal argument for Google's violation of GPLv2, and argues that moving to Glibc is Google's only realistic alternative. He also speculates that a lawsuit on the issue could be coming quite soon.

A dozen lawsuits and counting

All this is played out against a backdrop of "more than a dozen patent lawsuits over Android," including an Oracle lawsuit against Google over the use of the Java-based Dalvik virtual machine in Android, writes Mueller. In January, writing on FOSS Patents, Mueller suggested that Android might indeed infringe on Oracle's patents.

Google and the Android community have recently faced other charges over GPL violations. Last week, OpenLogic announced the results of a license-compliance assessment of 635 Android, iPhone, and iPad apps, finding that of the 66 apps with open source GPL/LPGL or Apache licenses, 71 percent failed to comply with license requirements. Apple iOS actually scored higher at compliance, with 32 percent compared to 29 percent compliance for Android apps, says the study.

Meanwhile, the open source and Linux kernel communities are becoming increasingly restive with Google over its use of Linux in projects such as Android, Chrome OS, and Google TV, where Linux gets intertwined with proprietary ambitions, and in some cases code.

Among other issues, many are upset about Google's lack of cooperation with the Linux kernel process, as well as its relative lack of code contributions to open source projects in general.

Somewhat similar concerns were voiced a decade ago when IBM invested $1 billion in Linux, yet IBM turned out to be a reasonably compliant open source citizen and helped boost Linux in the server space. Today, however, it is not only Google giving Linux too much love, in the view of some. Intel has so far played by the open source rules, but some worry about its influence over projects such as MeeGo and its acquisition of Wind River, and now computer giant HP appears is building its future on the Linux-based WebOS.

Without such giants, Linux might be a laudable, somewhat idealistic subplot to the history of computing. With it, Linux has the potential for world domination — but at the risk of compromising its open source soul.

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This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.