How can you tell if a closed program contains free code?

Question

Licenses for software and other works

If the library is just statically linked, that's one thing. But what if only a number of functions are copied into the code of a proprietary program?
I assume that the FSF is in charge of protecting free software. Where can I read about his activities in this direction (lawsuits, results)?

Answer 1

> How can you tell if a closed program contains free code?
I don't know what you mean by "closed program" (discontinued?), but what difference does it make if you plagiarized free software or non-free software? The methods of forensic examination will not change from this.
If you hope that someone here will tell you about them longer than in a nutshell (as Comrade Rou1997 did :), then I'm afraid you are hoping in vain. This is a whole direction in forensic science, in which even thematic journals are published. I am not at all an expert in it, but a number of comrades recommend the book for initial acquaintance:
- Zeidman, Bob. The Software IP Detective's Handbook: Measurement, Comparison, and Infringement Detection - Prentice Hall, 2011
Yes, I must warn you that when talking about free licenses, the author makes a couple of very gross mistakes. He also has a pronounced prejudice against free software, which he is not ashamed to admit. And, of course, he does not shy away from using propaganda terminology. And in general, you are not averse to speculating on topics that are not related to forensic examination itself (you will even find there about Yukos and Khodorkovsky passage :-). But, I believe, you have enough critical perception that all this does not interfere with extracting a rational grain from the book.

Answer 2

But what if only a number of functions are copied into the code of a proprietary program?

Determine by those that you copy: disassembler => function body hash => comparison.
But it depends on what you copy, how much and how important it is in your program, and how important your program is.
As long as you have all these indicators "at zero", there is absolutely no point in worrying.
It's not a problem to obfuscate the code, no one can disassemble the JVM and prove by "poking their nose" into the listing of its code, whether it is just a bytecode interpreter or really compiles something into machine code, no one needs it.

Answer 3

Just for reference and understanding (taken from wiki ):
The Foundation owns the copyright to most GNU software, as well as some non-GNU software. From any person who contributes to GNU packages, the Foundation requires a written statement of transfer of copyright in order to be able to defend the software in court in the event of a dispute. In addition, this allows you to change the license for a particular work, if necessary, without contacting each of the developers who have ever contributed to the program.

Answer 4

I assume that the main mechanism here is the employees of the stolen company. If a programmer finds out that the company he works for uses GPL code, he has every right to demand that they open the code, and will be legally protected. He will have direct evidence as a witness.