[fpc-pascal] respawn a daemon in Linux

[Mark Morgan Lloyd]

Michael Schnell wrote:
> On 01/14/2014 12:07 PM, Mark Morgan Lloyd wrote:
>>  You need to make sure that it doesn't try to restart if it's received 
>> a signal that the system's going down
>>
> I suppose the bash running the "loopmyprogram" script will get the kill 
> signal, as well and stop right away.

They'll get a TERM first, and five seconds later a KILL. You don't want 
to restart after that first signal, because if you wait until the second 
one you risk leaving files etc. associated with the program in an 
indeterminate state. I've had Qemu break a database inside NTFS by 
refusing to honour a shutdown.

So you can't restart after a KILL, shouldn't after a TERM, might not 
want to after an INT (which, as we were discussing a few days ago, 
includes ^C from the keyboard) but probably do want to restart after a 
HUP. At the very least, you need to make sure that your program 
propagates why it's stopped to whatever's started it.

-- 
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk

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