inode number -> pathname? (4.2BSD)

[Henry Spencer]

> ...  If it were possible to set the current working directory
> to a given inode and device, then pwd would give you the answer.  All
> the permission information, and even the bit denoting whether or not
> this inode refers to a directory is stored in the inode, and can easily
> be checked in such a call...

This proposal has the side effect of making a significant change to the
semantics of Unix file protection.  The permission bits on a Unix
directory are *not* sufficient for permission checking, because the
permissions of the directories above it in the tree also matter.  It
can be done the other way, where parent permissions don't matter --
I think Multics did it that way -- but this would require changes to
both programs (notably mkdir, which would have to tighten up directory
permissions) and user habits (making your home directory private no
longer suffices to make everything under it private).
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry