A decision in the GPL enforcement case in Germany between Christoph Hellwig (supported by the Software Freedom Conservancy) and VMware recently became public. The court dismissed the case after concluding that Hellwig failed to identify in the VMware product the specific lines of code for which he owned copyright. The GPL interpretation question was not addressed. Hellwig has indicated that he will appeal the court’s decision.

The case has attracted particular attention because the allegations involve interpretation of the scope of the copyleft feature of the GPL. This differs from prior GPL enforcement cases, which have involved relatively straightforward failures to meet the license requirements, such as failure to provide source code for software that was clearly licensed under the GPL.

This case involves code that VMware has repurposed from the Linux kernel to be included in a module that runs in VMware’s ESXi, to which related modifications to the ESXi code have also been made—all of which has been done so that drivers created for the Linux kernel can be used with ESXi. This presents the question of whether the manner in which VMware combined ESXi’s vmkernel with a Linux-kernel-code-containing module (vmklinux) results in vmkernel being subject to the GPL.

This case raises an issue that has similarities to the combination of proprietary drivers and the Linux kernel, but in reverse. In this case, the main body of code is proprietary (vmkernel) and the drivers are licensed under the GPL; in both cases, the code connecting the drivers to the main body of the kernel (when such a layer is used) is licensed under the GPL.

Although the court discusses the GPL issue, it offers no conclusions on that point. Rather, the decision is based on the high degree of specificity that the court is requiring for connecting the particular lines of code authored by Hellwig to the allegations of infringement. While at this point the case has been dismissed without addressing the GPL, seeing the degree of detail with which the court has recounted factual assertions and arguments that have been made by each side is of interest.

Legal analysis used to resolve this case would not be determinative of other cases for a number of reasons: the legal analysis needed to interpret the GPL for this sort of situation is likely to have a significant dependence on case-specific facts; there are differences from country to country in various aspects of relevant law, including in copyright law as well as in how evidence is presented; even for other cases in Germany, which has a civil law legal system, a judge’s decision does not have the precedential impact that is expected in common law countries.

Even without the impact of legal precedent, the case remains of interest as it could present (with an appeal ahead, this dismissal may not be the end) an opportunity to see how a judge addresses legal analysis in which technical details of how the software is built could matter.

Christoph Hellwig has published a brief note indicating his intention to appeal, along with links to the text of the decision (PDF in German) and to an unofficial English translation (PDF). The Software Freedom Conservancy has published a comment on this development, which includes links to other material about the case.

For anyone wishing to dive into the decision itself, be aware that much of the text is a recounting of assertions made by each of the parties. Although stated as conclusions, these are not conclusions reached by the court. The decision is organized into four parts (page numbers for the English translation):

• p 2: General factual background, including device drivers, kernel modules, and interfaces.
• p 4: Assertions by the Plaintiff (Hellwig).
• p 5: Assertions by the Defendant (VMware).
• p 13-22: The court’s reasons for the decision.