Papers about gLExec
gLExec is a program to make the required mapping between the grid world and the Unix notion of users and groups, and has the capacity to enforce that mapping by modifying the uid and gids of running processes. It used LCAS and LCMAPS for access control and the mapping engine. It can both act as a light-weight 'gatekeeper' replacement, and even be used on the worker node in late-binding (pilot job) scenarios. Through the LCMAPS SCAS client a central mapping and authorization service (SCAS, or any interoperable SAML2XACML2 service) can be used.
The description, design and caveats are described in the paper to the CHEP conference.
Local services, in particular computing services offered on Unix  and Unix-like platforms, use a different native representation of the user and group concepts. In the Unix domain, these are expressed as (numeric) identifiers, where each user is assigned a user identifier (uid) and one or more group identifiers (gid). At any one time, a single gid will be the .primary. gid (pgid) of a particular process, This pgid is initially used for group-level process (and batch system) accounting. The uid and gid representation is local to each administrative domain.