Subject: kernel hacking pointers
To: None <current-users@netbsd.org>
From: dustin sallings <dustin@spy.net>
List: current-users
Date: 10/06/1998 00:58:59
	So, I'm pretty far from a kernel hacker, but I've got a project
I'm really wanting to get into.

	What I want to do is put a layer on top of the filesystem to do
some kind of filename abstraction to rewrite a file path.  I really just
want a place to look before it looks on the disk.

	The idea is to have something kinda like plan9's bind command,
sort of a symlink that overrides filesystem paths and is valid for a given
process and all processes below it.  For instance (from the bind manpage
at http://plan9.bell-labs.com/magic/man2html/1/bind):

To compile a program with the C library from July 16, 1992: 

              mount /srv/boot /n/dump dump

              bind /n/dump/1992/0716/mips/lib/libc.a /mips/lib/libc.a

              mk

	Of course, I'm not looking to do the yesterday stuff taking daily
filesystem snapshots, just the process-level rewriting.

	Is this a completely crazy idea?  If it's possible to do it
without rewriting huge parts of filesystems, I'd like to play with it
some.  Any pointers?

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