The gpl-violations.org Vendor FAQ tries to give answers to questions asked by vendors/distributors of products including GPL-licensed software.
As a seller of GPL based products what is good practice ?
Remember the license requires you make source available to your customers with the product or to include a written offer. Putting a zip of the relevant sources on the Documentation CD is a great way to do this.
If you include GPL software, include a copy of the GPL with your license documentation and make sure it is clear that your product contains GPL software.
If you make available software/firmware updates via Internet, and the update or software/firmware image contains GPL software, you have to provide the corresponding source code for every single version.
This is not legal advice, if you have doubts consult your legal counsel.
What are common mistakes ?
Using standard boilerplate text which claims the entire software is (C) Copyright OurCompany. This is obviously not fully true if you use Free Software copyrighted by 3rd parties in the product.
Forgetting to include the written offer to the source code.
Including the wrong version of the source code. The source code has to be 1:1 corresponding to the executable (object) code actually shipped.
Forgetting to include the "scripts used to control compilation and installation of the executable", i.e. the tools required to compile and install the GPL licensed components.
Only including a Link to the GPL license text, instead of a verbatim copy.
Only including a download link to the source code, rather than a written offer to ship the source code on a physical storage medium customarily used for information interchange.
In the case of software distribution by making publicly available for download: Linking to a license text or source code on servers other than yours. This amounts to GPL Section "3c" (passing on a written offer), which is only valid for non-commercial distribution.
What should I do if our company has violated the license ?
Fix it. The same as you would fix a violation of any proprietary software license.
Another way of looking at this is to ask the question: would I infringe the copyright of IBM software, or Intel software, or HP software ?
Probably not - but if you do so with Linux you are violating Intel, IBM and HP licenses all at the same time. All three have copyright on significant portions of the Linux kernel. So by violating the GPL, you're actually infringing their copyright, too!
As a vendor where can I get help ?
There are a variety of sources of help and information. The first port of call should probably be your supplier of GPL software components. The GPL license is written to be as clear as possible but a lawyer can be helpful for complex issues like derivative works.
Sites such as github.com, gitlab.org, gitorious.org, or even the venerable sourceforge.net can help by providing a hosting site for GPL versions of software.
How do I make the community happy ?
The big value to the community is having access to the code. One of the most useful things that a company can do therefore is to contribute back changes they made. Putting the software somewhere accessible to all like sourceforge.net is really helpful too. Some vendors try and build communities around the code and get involved, others throw it over the wall and forget about it.
Won't this GPL stuff cost me a lot ?
No. Your duties are to provide either the source of the GPL components or a written offer included with the product.
There is no duty to third parties, there is no duty to support software created using your changes. The GPL also includes warranty disclaimers.
In addition the written offer is to provide the source at cost of delivery, not for free.
It is possible to meet the license requirements simply by including a copy of the GPL license in the manual, appropriate credit and a zip file of the relevant source on the accompanying CD-ROM to your product.
It will only cost you a lot if you set out to violate the license.