OSF DCE Application Development Guide--Introduction and Style Guide

OSF DCE Application Development Guide—Introduction and Style Guide

Finally, principals that do not meet any of the above criteria can be authorized as

any_other. The other_obj, any_other, and foreign_other types are distinguished by

cells: other_obj applies to the local cell, foreign_obj applies to speciﬁed foreign cells,

any_other applies to any cell.

The user_obj and group_obj types have less straightforward semantics. They refer to a

special principal and group that must be known to the ACL manager ‘‘out of band’’: that

is, they cannot be determined from the ACL entry itself. The semantics of the mask_obj,

which is applied to everything except the user_obj and other_obj entries, are also

complicated. The mask_obj is implemented to permit POSIX ACLs to more or less

maintain UNIX semantics for 000 permissions.

In general, the use of user_obj and group_obj is deprecated: they unnecessarily create a

special user, thus complicating the otherwise straightforward semantics of ACLs.

Unless you are implementing a ﬁle system, you probably do not need these types. (The

other_obj type is unobjectionable since it has well deﬁned semantics.) Similarly, the use

of mask_obj is deprecated because of its awkward semantics.

Thus it is recommended that you use only types from the following subset of entry types:

• user

• group

• other_object

• foreign_user

• foreign_group

• foreign_other

• any_other

These types allow for the most speciﬁc to the most general principals, both for local,

speciﬁc foreign cells, and for unspeciﬁed foreign cells.

The DCE ACL library ignores user_obj and group_obj, because there is no generic way

to determine the user and group owners of an arbitrary ACL protected object: the

semantics of ownership are application-speciﬁc. However, since these types are not

recommended for general use anyway, their absence should not be a serious limitation

for most applications that use the DCE ACL library.

3.4.3 ACL Managers

DCE entities expect to be able to access other DCE entities’ objects’ ACLs through a

standard set of DCE routines, knowing nothing more than the names of the objects. The

names of the objects are in the form of CDS pathnames.

The DCE ACL library is an implementation of the remote ACL (rdacl) interface,

designed in such a way as to allow any DCE application to use it instead of having to

implement the interface itself. In DCE 1.0, applications that wished to use the DCE

ACL functionality had to implement the full remote interface themselves; in DCE 1.1

this is no longer true. Once an application has registered certain information with the

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