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  From: Craig Markwardt <craigm@pcasun3.gsfc.nasa.gov>
  To  : Avery Pennarun <apenwarr@worldvisions.ca>
  Date: Wed, 26 May 1999 17:41:53 -0400 (EDT)

Re: pre-suspend notifications?

Avery Pennarun writes:
 > As far as I can tell, at least in 2.2 kernels, access to /dev/apm_bios is
 > controlled only by file permissions.  Is there a security risk in
 > 
 > 	chmod a+r /dev/apm_bios?
 > 

Now that I check more closely you are right, partially.  There are
permissions checks in place which prevent a non-privileged user
initiating a suspend or standby event.  Non-privileged processes can
receive events, but the kernel won't wait for them to respond.

Thus I think it is possible for a non-privileged xscreensaver process
to receive a suspend notification *after* the system has resumed the
next time.  In practice that is probably not a problem if apmd is
running, since apmd puts a lot of sleep time in before a suspend for
sync()ing, etc.

Craig