Subject: Re: Querying an userland program from the kernel
To: None <>
From: David Young <>
List: tech-kern
Date: 01/25/2004 02:01:03
On Sun, Jan 25, 2004 at 12:11:29AM -0500, der Mouse wrote:
> > A generalized "upcall" mechanism whereby the kernel can get help from
> > userland programs would be very nice for a whole pile of problems.
> > [U]sing sockets for kernel/userland messages makes a lot of sense.
> It does.

Socket interfaces are fine, but they are not convenient to delegate
to unprivileged users. A character device, however, you can "chmod 600
/dev/dev0 ; chown dyoung /dev/dev0".  It is also easy to create a dev0
inside a chroot jail.  And in anticipation of the day when NetBSD has
capabilities or some other process-granularity system for privileges,
names like /dev/dev0 will serve as convenient and familiar names for


David Young             OJC Technologies      Urbana, IL * (217) 278-3933