Writing a program that cannot be killed except by reboot

[Marco Negri]

mcgough at wrdis01.af.mil (Jeffrey B. McGough) writes:

>Is there anyway to block ALL signals to a program so that it
>may not be killed by kill???

>I know the manual says that sig 9 may not be caught or blocked
>but I was wondering if there might be a funny (strange, interesting)
>hack to get around this...

	I know one and only one situation in that a process can't be killed
	with SIGKILL signal.
	When it is slept, in kernel mode, with priority < PZERO.
	The second argument of sleep kernel is the "sleep priority".
	If this priority is less than PZERO *all* signal are ignored, but
	the process is slept, not ready.
	Don't exist any method to caugth signal 9 without sleeping the
	process forever (reboot).
	Bye. Marco
-- 
Marco Negri					Phone  : +39-2-7575242
Computer Science Dep. Milan University 		Fax    : +39-2-76110556
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