[gentoo-user] MailScanner: caught SIGTERM, aborting

[gentoo-user] MailScanner: caught SIGTERM, aborting

[Jarry]

Hi,
For whatever reason I can not stop/start MailScanner cleanly:

# /etc/init.d/MailScanner stop
* Stopping MailScanner...
* MailScanner: caught SIGTERM, aborting

# /etc/init.d/MailScanner start
* WARNING: MailScanner has already been started

Actually, MailScanner stops, but sendmail which has been
started by MailScanner init script is still there running:

# ps -e | grep sendmail
18676 ?        00:00:00 sendmail
18679 ?        00:00:00 sendmail

Even whenn I killall sendmail, I still get the above mentioned
warning, and can not start MailScanner. And that is a problem,
because MailScanner is restarted every hour (to prevent eating
all resources). I checked /var/run and /var/lock, there is
no trace of MailScanner or sendmail running, yet I can not
re-start Mailscanner. How can I fix this problem?

Jarry

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Re: [gentoo-user] MailScanner: caught SIGTERM, aborting

[Mike Kazantsev]

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On Sun, 24 May 2009 11:10:04 +0200
Jarry <mr.jarry@gmail.com> wrote:

> # /etc/init.d/MailScanner stop
> * Stopping MailScanner...
> * MailScanner: caught SIGTERM, aborting


Looks like there's a line in "stop" section that kills the script
itself. Try looking for a lines like these:

  pkill MailScanner
  killall MailScanner
  start-stop-daemon --stop --name MailScanner

Sure, they might be killing the app as well (if the process has
MailScanner in it's name), but there should be full path or pid-based
line instead, so the initscript will exit cleanly.


> # /etc/init.d/MailScanner start
> * WARNING: MailScanner has already been started


Following command should "wipe" initscript memory:

  /etc/init.d/MailScanner zap

...so it'll think MailScanner wasn't even started, but that should be
used as a workaround rather than a solution since it leaves init-system
in different state than it thinks it is.
Direct effect is that it won't execute "stop" action on shutdown since
it won't know the script even started.


> Actually, MailScanner stops, but sendmail which has been
> started by MailScanner init script is still there running:
> 
> # ps -e | grep sendmail
> 18676 ?        00:00:00 sendmail
> 18679 ?        00:00:00 sendmail


Could be because of aforementioned script "self-destruction".
If sendmail really started by the same script, not as a dependency,
that is.


> Even whenn I killall sendmail, I still get the above mentioned
> warning, and can not start MailScanner. And that is a problem,
> because MailScanner is restarted every hour (to prevent eating
> all resources). I checked /var/run and /var/lock, there is
> no trace of MailScanner or sendmail running, yet I can not
> re-start Mailscanner. How can I fix this problem?


Try using "start-stop-daemon -m/-p/--exec" to start and stop binaries,
instead of relying on process names (which can be easily changed, btw)
and try to use app-created pidfiles, if the launched app has this
capability, since it should know better which of it's processes should
receive stop signal.


-- 
Mike Kazantsev // fraggod.net

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Re: [gentoo-user] MailScanner: caught SIGTERM, aborting

[Jarry]

Mike Kazantsev wrote:

>> # /etc/init.d/MailScanner stop
>> * Stopping MailScanner...
>> * MailScanner: caught SIGTERM, aborting
> 
> Looks like there's a line in "stop" section that kills the script
> itself. Try looking for a lines like these:
>   pkill MailScanner
>   killall MailScanner
>   start-stop-daemon --stop --name MailScanner

The /etc/init.d/MailScanner script looks so:
----------------------------------
#!/sbin/runscript
opts="${opts} reload"
depend() {
         need net mta
         use logger dns }

start() {
         ebegin "Starting MailScanner"
         /usr/sbin/check_MailScanner >/dev/null
         RETVAL=$?
         [ ${RETVAL} -eq 0 ] && touch /var/lock/subsys/MailScanner
         [ ${RETVAL} -eq 0 ] && rm -f /var/lock/subsys/MailScanner.off
         eend ${RETVAL}
}

stop() {
         ebegin "Stopping MailScanner"
         killall -15 MailScanner
         RETVAL=$?
         [ ${RETVAL} -eq 0 ] && rm -f /var/lock/subsys/MailScanner
         [ ${RETVAL} -eq 0 ] && touch /var/lock/subsys/MailScanner.off
         eend ${RETVAL}
}
# restart () {} and reload () {} removed
----------------------------------

> Sure, they might be killing the app as well (if the process has
> MailScanner in it's name), but there should be full path or pid-based
> line instead, so the initscript will exit cleanly.
> 
>> # /etc/init.d/MailScanner start
>> * WARNING: MailScanner has already been started
> 
> Following command should "wipe" initscript memory:
> 
>   /etc/init.d/MailScanner zap

Yes, this works. But as you said, it is just workaround. Not very
clean solution...

>> Actually, MailScanner stops, but sendmail which has been
>> started by MailScanner init script is still there running:
>>
>> # ps -e | grep sendmail
>> 18676 ?        00:00:00 sendmail
>> 18679 ?        00:00:00 sendmail
> 
> Could be because of aforementioned script "self-destruction".
> If sendmail really started by the same script, not as a dependency,
> that is.

Don't know exactly how sendmail is started, but according to
MailScanner install messages, I had to remove it from default
runlevel. MailScanner itself takes care of starting sendmail...

Jarry

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Re: [gentoo-user] MailScanner: caught SIGTERM, aborting

[Mike Kazantsev]

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On Sun, 24 May 2009 15:37:51 +0200
Jarry <mr.jarry@gmail.com> wrote:

> Mike Kazantsev wrote:
> 
> > Looks like there's a line in "stop" section that kills the script
> > itself. Try looking for a lines like these:
> >   pkill MailScanner
> >   killall MailScanner
> >   start-stop-daemon --stop --name MailScanner
> 

...

> depend() {
>          need net mta
>          use logger dns }


That's what probably starts sendmail as a dependency (mta), so if you
want to stop both MailScanner and sendmail you can just use

  /etc/init.d/sendmail stop

...or something like that (I'm not sure about initscript name for
sendmail) - it should stop everything that depends on sendmail
(including MailScanner) then the sendmail itself.


> stop() {
>          ebegin "Stopping MailScanner"

And here's the killer line:

>          killall -15 MailScanner


I'd still suggest looking through available docs to see if the app can
create pidfile for itself and replacing that line with following:

  start-stop-daemon --stop -p /path/to/pidfile

It'll give error code if it won't find the process, just as killall
does.
"-15" is SIGTERM (I guess that's true for all gentoo platforms) and is
default for nearly all kill-like commands, so there's little need to
specify it explicitly in gentoo.


And if you want a faster solution, I see at least two options:

  1. Looking at "ps aux | grep MailScanner" output to see exact
    invocation line and using one of the following:

      start-stop-daemon --stop --exec /path/to/bin/MailScanner
      pkill -f /path/to/bin/MailScanner

    I'd prefer first one, for consistency.

  2. Just rename init.d script to something w/o MailScanner in it's name.
    It might break something only if any other scripts depend on this
    one, but it sure looks like the easiest way to me ;)


>          RETVAL=$?
>          [ ${RETVAL} -eq 0 ] && rm -f /var/lock/subsys/MailScanner
>          [ ${RETVAL} -eq 0 ] && touch /var/lock/subsys/MailScanner.off
>          eend ${RETVAL}
> }

...

> Don't know exactly how sendmail is started, but according to
> MailScanner install messages, I had to remove it from default
> runlevel. MailScanner itself takes care of starting sendmail...


That seems strange, since sendmail should be already started as a
dependency anyway, so it shouldn't hurt to have it at any runlevel.

But since there's a check on killall and you've mentioned
self-restarting mechanism, I guess it might indeed restart itself and
sendmail independently of init-scripts, so removing sendmail from
runlevel serves exactly one purpose: it's init-script won't fail if the
process won't be there.

Also it looks like leaving sendmail running after MailScanner itself
was closed is expected behaviour or app (not initscript) bug, since
there's no mention of sendmail stopping in the script (unless it checks
that /var/lock paths) and MailScanner didn't close it upon receiving
SIGTERM, which seem to be expected way to stop it.


All in all, I think there's no reason to worry about why and how
sendmail is started as long as it works, so bogus killall line should
be the only wrong thing here.


-- 
Mike Kazantsev // fraggod.net

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Re: [gentoo-user] MailScanner: caught SIGTERM, aborting

[Jarry]

Mike Kazantsev wrote:

>>> Looks like there's a line in "stop" section that kills the script
>>> itself. Try looking for a lines like these:
>>>   pkill MailScanner
>>>   killall MailScanner
>>>   start-stop-daemon --stop --name MailScanner
> ...
>> depend() {
>>          need net mta
>>          use logger dns }
> 
> That's what probably starts sendmail as a dependency (mta), so if you
> want to stop both MailScanner and sendmail you can just use
> 
>   /etc/init.d/sendmail stop

# /etc/init.d/sendmail stop
* Stopping MailScanner...
* MailScanner: caught SIGTERM, aborting
* ERROR: cannot stop sendmail as MailScanner is still up

# /etc/init.d/MailScanner stop
* Stopping MailScanner...
* MailScanner: caught SIGTERM, aborting
# /etc/init.d/sendmail stop
* Stopping MailScanner...
* MailScanner: caught SIGTERM, aborting
* ERROR: cannot stop sendmail as MailScanner is still up

As you see, it does not work. I think that start/stop script
is somehow screwed. I'm going to ask on mailscanner mailing list.
Thanks for your effort.

Jarry
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Re: [gentoo-user] MailScanner: caught SIGTERM, aborting

[Mike Kazantsev]

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On Sun, 24 May 2009 16:36:28 +0200
Jarry <mr.jarry@gmail.com> wrote:

> Mike Kazantsev wrote:
> 
> >>> Looks like there's a line in "stop" section that kills the script
> >>> itself. Try looking for a lines like these:
> >>>   pkill MailScanner
> >>>   killall MailScanner
> >>>   start-stop-daemon --stop --name MailScanner
> > ...
> >> depend() {
> >>          need net mta
> >>          use logger dns }
> > 
> > That's what probably starts sendmail as a dependency (mta), so if you
> > want to stop both MailScanner and sendmail you can just use
> > 
> >   /etc/init.d/sendmail stop
> 
> # /etc/init.d/sendmail stop
> * Stopping MailScanner...
> * MailScanner: caught SIGTERM, aborting
> * ERROR: cannot stop sendmail as MailScanner is still up
> 
> # /etc/init.d/MailScanner stop
> * Stopping MailScanner...
> * MailScanner: caught SIGTERM, aborting
> # /etc/init.d/sendmail stop
> * Stopping MailScanner...
> * MailScanner: caught SIGTERM, aborting
> * ERROR: cannot stop sendmail as MailScanner is still up
> 
> As you see, it does not work. I think that start/stop script
> is somehow screwed. I'm going to ask on mailscanner mailing list.
> Thanks for your effort.

But you didn't change the script, of course it WILL fail just as it did.

Replace killall line with something sensible and only then try to use
it. It's obviously broken otherwise.

-- 
Mike Kazantsev // fraggod.net

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Re: [gentoo-user] MailScanner: caught SIGTERM, aborting

[Stroller]

On 24 May 2009, at 14:37, Jarry wrote:
> ...
> The /etc/init.d/MailScanner script looks so:
> ----------------------------------
> #!/sbin/runscript
> opts="${opts} reload"
> depend() {
>        need net mta
>        use logger dns }
>
> start() {
>        ebegin "Starting MailScanner"
>        /usr/sbin/check_MailScanner >/dev/null
>        RETVAL=$?
>        [ ${RETVAL} -eq 0 ] && touch /var/lock/subsys/MailScanner
>        [ ${RETVAL} -eq 0 ] && rm -f /var/lock/subsys/MailScanner.off
>        eend ${RETVAL}
> }
>
> stop() {
>        ebegin "Stopping MailScanner"
>        killall -15 MailScanner
>        RETVAL=$?
>        [ ${RETVAL} -eq 0 ] && rm -f /var/lock/subsys/MailScanner
>        [ ${RETVAL} -eq 0 ] && touch /var/lock/subsys/MailScanner.off
>        eend ${RETVAL}
> }
> # restart () {} and reload () {} removed
> ----------------------------------


That's the ugliest init.d script ever. It looks like it fell out of  
the ugly tree, hit every branch on the way down and now not even its  
mother could love it. &c &c.

Suggest you follow Mike's advice & rewrite the script based on the  
other examples installed on your system, the ones written by Gentoo  
devs. Unfortunately, if you don't know Bash very well, this may be a  
bit of a mission, but I'm afraid it needs doing.

The script needs to save the process ID of the process that it starts  
when it opens the application, then to stop the app it needs to kill  
that specific PID, calling it by number. It needs to check that the  
commands have worked -  for instance: was it successful when it  
executed `kill $PID`? See Example 6-1 of the Bash Scripting Guide <http://tldp.org/LDP/abs/html/exit-status.html 
 >. See also use of special variable $! in chapter 9 of ABSGuide and  
also <http://www.unix.com/shell-programming-scripting/26377-pid-bash.html 
 >, but as Mike observes start-stop-daemon should take care of that  
for you.

Stroller.