What reason should /dev/kmem not be world-readable?

[Mark J. Hewitt]

>  ...reading clists...

Int the good old days, we acheived this by adding a little code to the
tty interrupt routine - when it placed a character on the output queue,
it looked to see if there was a second tty to receive the character
(from a kernel variable poked by a runnable by root only program called
`spy'!), and stuffed it on that queue too.  This was on UNIX Ed. 6.
Later versions are a little harder because the queue is written in one
of several places (multiplexer files, line disciplines, probably
streams, etc...), but I did the same thing on a 4.2bsd system despite
this.  

Mark J. Hewitt

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