[nos-bbs] JNOS kill signal

Michael Fox - N6MEF n6mef at mefox.org
Mon Aug 8 12:33:49 EDT 2016


Is there a preferred signal to send to JNOS to cause it to exit?

 

Background:

JNOS will occasionally hang/freeze (rare, but it happens).  I have a
watchdog script that will detect an unresponsive JNOS and restart it.  The
conventional signal to send a process is SIGTERM, which will typically cause
a graceful exit.  One would expect the process to close open files, remove
lock files, etc.  But JNOS ignores SIGTERM.  I tried a few others:

 

SIGHUP = not really a termination signal.  Equivalent of user hang up.  But
JNOS normally terminates with exit code 129

 

SIGINT  = equivalent of CTRL-C.  JNOS normally terminates with exit code 1.
I've been using this successfully.  But yesterday I had an occasion where
JNOS still didn't terminate.

 

SIGQUIT = equivalent of CTRL-\.  Typically, it terminates a process and
causes a core dump.  JNOS normally terminates with exit code 131.  But I
don't find a core dump anywhere.  (And I don't know if Maiko would find it
helpful or not.)

 

SIGKILL = most aggressive.  Cannot be trapped by the process.  JNOS normally
terminates with exit code 137

 

I was going to adjust my script to try SIGINT first (since it has been
mostly successful so far) and, if it still won't die, then try SIGKILL.  But
if the other signals are not handled any more gracefully, then maybe it's
better to just send SIGKILL in the first place.

 

So, is there a preferred signal that will cause the most graceful
termination of JNOS or should I just send SIGKILL and be done with it.

 

Michael

N6MEF

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