Currently, every ebuild in the main Gentoo repository is required to have a valid LICENSE entry. However, the syntax of this entry is not officially defined and the entry itself is only used when outputting package details.

Furthermore, some software requires that a user interactively accept its license for its author's to consider it legally binding. This is currently implemented using eutils.eclass .

Many users wish to regulate the software they install with regards to licenses for various reasons . Some want a system free of any software that is not OSI-approved; others are simply curious as to what licenses they are implicitly accepting.

Ebuild LICENSE Variable Most ebuilds are for software which is released under a single license. In these cases, the current LICENSE variable can remain as is. For example: LICENSE="single-license" However, there are several ebuilds for software which is released under several licenses, of which the user must accept one, some or all . To complicate this, some ebuilds include optional components which fall under a different license. To accommodate these cases, LICENSE syntax should accommodate all functionality offered by a DEPEND string. To keep things simple, this GLEP proposes that the syntax be identical. For example: LICENSE="mandatory-license || ( choosable-licence1 chooseable-license-2 ) useflag? ( optional-component-license )" License names may contain [a-zA-Z0-9] (english alphanumeric characters), _ (underscore), - (hyphen), . (dot) and + (plus sign). They must not begin with a hyphen, a dot or a plus sign.

License Groups Almost all users are willing to install any software that is FSF-approved. Other users are willing to install any software and implicitly accept its license. To this end, implementations will also need to handle grouping of licenses. At a minimum, there needs to be the groups GPL-COMPATIBLE , FSF-APPROVED , OSI-APPROVED and NON-MUST-HAVE-READ . NON-MUST-HAVE-READ licenses are those that don't require manual acceptance for to be considered legally binding. This is the current behaviour of portage. These groups are defined in a new file license_groups in the profiles subdirectory of the tree (or overlays). Details of handling groups defined in overlays is implementation dependent. The format of this file is <groupname> <license1> <license2> ... <licenseN> Also any line starting with # is ignored and may be used for comments. Group names use the same syntax as normal license names. Also license groups may contain other groups. License groups may not contain negated elements, so a group mygroup foo -bar -bla is illegal.

ACCEPT_LICENSE This GLEP proposes that a user be able to explicitly accept or decline licenses by editing a new variable ACCEPT_LICENSE in /etc/make.conf . Again, to keep things simple, the syntax should be similar to that of other incrementals. For example: ACCEPT_LICENSE="-* accepted-license -declined-license" As an extension, ACCEPT_LICENSE must also support license groups. This GLEP proposes that the license group be prepended by the special character " @ ". For example: ACCEPT_LICENSE="-* @FSF-APPROVED" License groups may be negated with the result that all elements of that group are also negated. Portage will also offer a package.license facility to offer this functionality on a per-package base (analog to package.keywords), other implementations may implement such a facility differently or not at all.