Re: [9fans] permissions

["Douglas A. Gwyn" <DAGwyn@null.net>]

Matthew Hannigan wrote:
> Is the distinction between x and r for directories
> really that useful?   When does it matter?  I can
> only think of "inbox" type directories.
> I'm still thinking of being able to get rid of the
> 'x' permission on everything.

There is no canonically "right" answer to such a question.
If you think of the permission bits as providing per-file
(or per-entry) information that can be used by some
algorithm that enforces some security policy, then we
need to know the specific policy before being able to
give a specific answer.

It is certain that a process that can read an executable
image can in principle "execute" it by acting as an
interpreter.  Therefore for the "x" bit to be more useful
it needs to grant access to some additional capability.
In the case of a directory file, traditionally "r" and "x"
differ in that one means "can traverse as a pathname
component" while the other means "can read its entries".
These are definitely not the same thing.