[Haskell-beginners] POSIX signals and deamons

[Emanuel Koczwara]

Hi,

   I'm trying to create a simple daemon with hdaemonize. The deamon runs 
ok, but i'm having trouble with signals. Here is my test case:


import Control.Monad
import Control.Concurrent
import System.Posix.Syslog
import System.Posix.Signals
import System.Posix.Daemonize


main = daemonize $ do
   withSyslog "my-test-daemon" [PID] DAEMON $
     syslog Info "daemon started"
   installHandler sigKILL (Catch killHandler) Nothing
   forever $ threadDelay 1000


killHandler = withSyslog "my-test-daemon" [PID] DAEMON $ do
   syslog Info "kill signal received"


When I run it:

$ ./test
$

Everything works great:

$ ps aux | grep test
emanuel  12790  2.6  0.0   6552   852 ?        S    20:57   0:00 ./test

and:

# tail /var/log/daemon.log
Nov 14 20:52:06 emanuel-laptop my-test-daemon[12689]: daemon started

when I do:

$ kill -9 12790

process no longer exist:

$ ps aux | grep test
$

but/var/log/daemon.log doesn't change:

# tail /var/log/daemon.log
Nov 14 20:52:06 emanuel-laptop my-test-daemon[12689]: daemon started

It looks like my sigKILL handler isn't called, why?


Thanks,
Emanuel