naming directories

[Glenn Skinner]

I've posted to new.sources a set of files and diff -c outputs for
incorporating naming directories into 4.2 bsd systmes.

The concept of a naming directory is taken from "Proposals for enhancements
of UNIX on the VAX", UCB CSRG TR/4, August, 1981.  This document contains
proposals for many features to add to 4.1 bsd; it describes preliminary
thoughts on what later turned into 4.2 bsd.  Naming directories were proposed,
but didn't make it into 4.2, presumably due to lack of time.

Each process in a system supporting naming directories has an additional
associated directory beyond the normal working and root directories.  This
new directory, the naming directory, embodies a starting point for paths
starting with '@', just as the root directory is the starting point for
paths starting with '/'.

There is a new namedir system call for changing a process's naming directory;
it is analagous to the chdir and chroot system calls.

We've had this code installed on our system for about a month now and are
quite happy both with the implementation and with the naming directory
feature itself.

A separate distribution (to net.emacs) contains modifications to emacs
to handle naming directories.

Along with the changes to the C shell required for naming directory support,
we've added a new built in variable "hardpaths" for making life with symbolic
links easier.  When hardpaths is set, the C shell resolves each directory
pathname it encounters to contain no symbolic links, replacing the pathname
with an equivalent path containing only hard links.  We've found this variable
to be a great aid to sanity when coping with an environment rich in symbolic
links.

		-- Glenn Skinner
		National Semiconductor, Microprocessor Systems Division
		(408) 733-2600 x 335
		{fortune,menlo70,mtxinu}!nsc!glenn