Logilic

Logilic is a solution to deal with the complexity of the software licenses when mixing multiple types of licenses. For example when you have to mix proprietary and copyleft licenses. It helps you cope with your duties when you deliver your software in binary form to your customer.

Logilic is organized in 3 parts:

• rules to reason about licenses in predicates.pl. You should not modify them.
• facts about licenses and their consequences in licenses.pl. Should be handled in cooperation with your legal department.
• project specific facts like how libraries are linked (statically or dynamically) with your executables and the versions of the components. Should be handled by the technical team or auto-generated during your build process. There are examples of such decriptions in project1.pl and project2.pl.

Usage

Projects must declare their components using the library, executable, dynamiclink, staticlink, testtool and buildtool predicates.

Once project facts are loaded like this using GNU Prolog:

$ ./logilic project1.pl

Or a binary has been generated like this using GNU Prolog or SWI Prolog and launched:

$ ./logilic_compile project1.pl
$ ./logilic_project1

you can use the query language like this:

| ?- invalid_components(L).

L = []

(1 ms) yes

This should return an empty list to be sure that all components have a known license.

To return the list of components that need actions on delivery to the customer:

| ?- duties(L).

L = [(xbmc,provide_sourcecode),(openssl,mention_in_doc),(qt,provide_sourcecode)]

yes

If you do the same thing but loading project2.pl instead of project1.pl which differs only by linking statically prog1 with Qt. You'll have this result:

| ?- duties(L).

L = [(xbmc,provide_sourcecode),(openssl,mention_in_doc),(qt,provide_sourcecode),(prog1,provide_sourcecode)]

yes

You'll have to provide the source code of prog1 as a result...

To check that the licenses of the various dependencies on an executable are compatible:

| ?- licenses('xbmc', L), compatible_licenses(L).

L = [gpl_license]

yes

Examples have been tested with GNU Prolog 1.4.1 and SWI Prolog 6.0.2.