Locking the sound device?

[Dave Bartlett]

In article <4442 at idunno.Princeton.EDU>, subbarao at phoenix.Princeton.EDU
(Kartik Subbarao) writes:
|> In article <1990Dec2.163300.11093 at Neon.Stanford.EDU>
frankjr at neon.stanford.edu writes:
|> >
|> >When I am using a sun sparcstation 1 from the console, is there any
way to
|> >prevent another user from telneting to my machine, and playing
sounds on it?
|> 
|> Sure - from audio(4) :
|>  
|>  `` The audio device is treated as an exclusive  resource:  only
|>     one  process  may typically open the device at a time.  How-
|>     ever, two processes may simultaneously access the device  if
|>     one opens it read-only and the other opens it write-only. ''
|> 		 
|> 
|> So either write a program that does open("/dev/audio", O_RDWR), or
just
|> have a process running in the background like "cat > /dev/audio &".
|> 
|> That'll silence your SPARCstation.
|> 
|> >The other questions is this.  Is there a way to prevent a user from
telneting
|> >on to the machine while I am using it, and do an xloadimage on my
display?
|> 
|> Weeeeeeeeeeeelllllll, you could be REALLY nasty and open all the
pty's to
|> prevent any more logins, but even then someone could rsh into your
machine
|> and wreck havoc. There is really no way from stopping someone
running
|> processes on your machine if you're not priviledged.
|> 
|> >Lastly, there is a program called decay which effectively makes the
image on
|> >your screen "melt", the other program I have seen is one that a
little person
|> >comes on the screen in the lower left corner, and pushes your screen
off the
|> >side of your monitor.  Is there any way to prevent these from
working if the
|> >user invoking them is not on the console.
|> 
|> Oh yes, don't I know them well :-). Nope - there's really no way
currently
|> to "protect" your sun in this fashion. Maybe there will be sometime
later,
|> but I doubt it.. Besides, its too much fun ;-).
|> 
|> 
|> 			-Kartik
|> 
|> 
|> 
|> 
|> >ps.  Does anyone know where these neat but annoying little demos are
that
|> >mess with your screen such as decay...brush... or anyother little
hacks..
|> 
|> (I love this nonchalant P.S. statement.)
|> 
|> 
|> (I need a new .signature -- any suggestions?)
|> subbarao@{phoenix or gauguin}.Princeton.EDU -|Internet
|> kartik at silvertone.Princeton.EDU (NeXT mail)       -|	
|> SUBBARAO at PUCC.BITNET			          - Bitnet


If you have mit magic cookie running (xauth), then you can use that to
stop
 people from display X-clients on your console. It creates a sizeable
random
 number that a user must have to have one of their X-clients connect to
your
 X-server. I think it is included with Openwindows. I am not an expert
in this
 area, so I am not going into great detail. Of course, a user can start
up
 his own X-server on your console, but then again, you can also type a
 /bin/rm -rf $HOME/*  :), that'll teach them.

--
Dave Bartlett - "They're not booing.  They're just chanting `Dave!
Dave!'"

%include <std.disclaimers>

University of Akron - Akron, Ohio
EMAIL - dlb at vonneuman.cs.uakron.edu
	r3dlb at vax1.cc.uakron.edu