How to interrupt hung boot process?

[Tim Judd]

On Fri, 2009-02-20 at 22:32 +0000, Dieter wrote:
> Working on updating a amd64 box from 7.0 to 7.1.
> A shell script called from rc.local hung.
> (Still don't know why, works fine in 7.0, works
> fine in 7.1 executed manually once system is up.)
> Tried ^C, ^\, ^P and nearly every other key on the
> keyboard.  They echo, but nothing will interrupt
> the hung process.  I had to press the reset button.
> 
> Back in the day, typing ^C on the console would
> interrupt the boot process and give you a shell
> prompt.  How do I interrupt the boot process
> with FreeBSD?
> 
> Is there a way to have getty start before running
> rc.local?

If a shell script traps the signals, there is nothing you can do except
by calling a SIGKILL to the PID, which requires the system to be in
Multi-User Mode.