[Users] Question about forking
Tim Madorma
tmadorma at gmail.com
Wed May 16 22:52:51 CEST 2007
Hey Anatoly,
Your patch seems to work great. I'll let you know if I run into any
issues. I would go ahead and commit the new patch.
Thanks for the help.
Tim
On 5/16/07, Tim Madorma <tmadorma at gmail.com> wrote:
> Great. thanks a lot. I'll try it then.
>
> On 5/16/07, Anatoly Pidruchny <apidruchny at newxt.com> wrote:
> > Tim,
> >
> > I found a difference in signal handling in non-daemonized vs daemonized
> > mode. When the main openser process daemonizes itself, it also creates a
> > new process group and session, puts itself into the new process group
> > and becomes its leader. Then later it can send signals to all the
> > processes in the process group. It means the signal will be delivered to
> > all the children, children of children and so on. In non-daemonized mode
> > it only sends signals to its direct children.
> >
> > I will try to modify code to create a new process group also when -D
> > option is used (but only when -F is not used). I will let you know when
> > a modified patch is ready.
> >
> > Thanks,
> >
> > Anatoly.
> > > Hi Anatoly,
> > >
> > > That is what I did in the first example that I sent to you today.
> > > Running manually with the -D option has the same results as when
> > > executing openser with runsv.
> > >
> > > thanks,
> > >
> > > Tim
> > >
> > > On 5/16/07, Anatoly Pidruchny <apidruchny at newxt.com> wrote:
> > >> Tim,
> > >>
> > >> I can not explain why it behaves differently. But can you also try the
> > >> same test with -D option, but without using runsv?
> > >>
> > >> Anatoly.
> > >> > Hi Anatoly,
> > >> >
> > >> > Thanks for your work-around - I'll try it. However, I did try the test
> > >> > you described without the -D option and here are the results:
> > >> >
> > >> > root at homer:/# ps -ef | grep openser
> > >> > sipproxy 29793 29786 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29788 29786 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29791 29786 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29789 29786 0 12:52:24 ? 0:00 openser
> > >> > root 29797 29266 0 12:52:28 pts/1 0:00 grep openser
> > >> > sipproxy 29795 29786 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29786 1 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29794 29786 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29792 29786 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29790 29787 0 12:52:24 ? 0:00 openser
> > >> > sipproxy 29787 29786 0 12:52:24 ? 0:00 openser
> > >> >
> > >> > root at homer:/# kill 29786
> > >> > root at homer:/# ps -ef | grep openser
> > >> > root 29799 29266 0 12:52:50 pts/1 0:00 grep openser
> > >> >
> > >> > As you can see, the child (29787) kills the grandchild (29790) when
> > >> > the parent (29786) is killed. I'm not sure why it behaves differently.
> > >> >
> > >> > Tim
> > >> >
> > >> > On 5/16/07, Anatoly Pidruchny <apidruchny at newxt.com> wrote:
> > >> >> Hi Tim,
> > >> >>
> > >> >> As far as I know, the problem with the left over openser process that
> > >> >> you described is not caused by the patch. If you run openser manually
> > >> >> without -D option, then kill the main process, you will get
> > >> exactly the
> > >> >> same result. The main openser process will kill all its children, but
> > >> >> will not kill its grandchildren. The reason is that the main openser
> > >> >> process does not know anything about its grandchildren.
> > >> Theoretically,
> > >> >> the process that forked a child (for example, your process with PID
> > >> >> 29744) is supposed to kill its children (for example, your process
> > >> with
> > >> >> PID 29747) when it is terminated. But this does not happen. I
> > >> think it
> > >> >> is a known issue (bug?) with openser. May be if you open a feature
> > >> (or
> > >> >> bug?) request then this issue will be resolved.
> > >> >>
> > >> >> By the way, we do not have this problem. I think the reason is
> > >> that you
> > >> >> use some module that we do not use. I grepped the openser sources and
> > >> >> found a number of places in modules where a child process is
> > >> forked. In
> > >> >> our case, I think we never hit code that creates any of the "child
> > >> of a
> > >> >> child" processes.
> > >> >>
> > >> >> As a workaround, did you try to kill all the left over openser
> > >> processes
> > >> >> from the ./finish file?
> > >> >>
> > >> >> Regards,
> > >> >>
> > >> >> Anatoly.
> > >> >> > Hey Anatoly,
> > >> >> >
> > >> >> > I've been running with your patch and it works, but there is one
> > >> issue
> > >> >> > that I want to bring up. After openser forks, it creates
> > >> processes as
> > >> >> > follows:
> > >> >> >
> > >> >> > sipproxy 29745 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29751 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29748 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29750 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29743 29432 0 11:32:37 pts/2 0:00 openser -D
> > >> >> > sipproxy 29752 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29744 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29746 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29749 29743 0 11:32:38 pts/2 0:00 openser -D
> > >> >> > sipproxy 29747 29744 0 11:32:38 pts/2 0:00 openser -D
> > >> >> >
> > >> >> > You can note that the parent PID is 29743 and has several children,
> > >> >> > but for some reason, process 29744 also spawns the child process
> > >> >> > 29747. When I use runsv to start the process, it notes the process
> > >> >> > that it creates is 29743. Then when I terminate with runsv, it
> > >> kills
> > >> >> > 29743 - which kills all of it's children, but leaves PID 29747
> > >> >> > running. Since it's parent was killed, PID 29747 is adopted by the
> > >> >> > init process (PID 1). Here is an example of this done by hand
> > >> (with a
> > >> >> > kill of 29743):
> > >> >> >
> > >> >> > root at homer:/# kill 29743
> > >> >> > root at homer:/# ps -ef | grep openser
> > >> >> > root 29756 29266 0 11:35:19 pts/1 0:00 grep openser
> > >> >> > sipproxy 29747 1 0 11:32:38 pts/2 0:00 openser -D
> > >> >> >
> > >> >> > Please let me know if you can assist here.
> > >> >> >
> > >> >> > thanks much,
> > >> >> > Tim
> > >> >> >
> > >> >> > On 5/7/07, Anatoly Pidruchny <apidruchny at newxt.com> wrote:
> > >> >> >> Hi, Tim,
> > >> >> >>
> > >> >> >> there is a patch (that I submitted) that allows to run the main
> > >> >> openser
> > >> >> >> process in foreground and fork child processes as usual. No
> > >> developer
> > >> >> >> has reviewed the patch yet. I hope this patch will be accepted
> > >> >> soon. The
> > >> >> >> patch is simple and we use it for a long time now. You can also
> > >> >> take the
> > >> >> >> patch and use it.
> > >> >> >>
> > >> >> >> The patch is:
> > >> >> >>
> > >> >>
> > >> http://sourceforge.net/tracker/index.php?func=detail&aid=1689998&group_id=139143&atid=743022
> > >>
> > >> >>
> > >> >> >>
> > >> >> >>
> > >> >> >> Anatoly
> > >> >> >> > Hi,
> > >> >> >> >
> > >> >> >> > I want to start openser with runsv which requires that the
> > >> starting
> > >> >> >> > process run in the foreground. My problem is that I also want to
> > >> >> >> > listen on a couple of different ports. When I set forking =
> > >> yes, it
> > >> >> >> > will listen on multiple ports, but runsv won't work. When I set
> > >> >> >> > forking=no, then openser will only listen on the first specified
> > >> >> port.
> > >> >> >> >
> > >> >> >> > Is there any way around this? Can I have the starting process
> > >> >> run in
> > >> >> >> > the foreground and fork other processes that listen to the
> > >> ports in
> > >> >> >> > the background?
> > >> >> >> >
> > >> >> >> > Here is the error message:
> > >> >> >> >
> > >> >> >> > WARNING: no fork mode and more than one listen address
> > >> >> found(will use
> > >> >> >> > only the the first one)
> > >> >> >> >
> > >> >> >> > Here are the associated configuration lines:
> > >> >> >> >
> > >> >> >> > fork=no
> > >> >> >> >
> > >> >> >> > children=32
> > >> >> >> >
> > >> >> >> > # Local IP address/port pairs to listen to
> > >> >> >> > listen=65.185.233.55:5061
> > >> >> >> > listen=65.185.233.55:5062
> > >> >> >> >
> > >> >> >> > # Alias IP address/port pairs
> > >> >> >> > alias=65.185.233.104:5061
> > >> >> >> > alias=65.185.233.104:5062
> > >> >> >> >
> > >> >> >> > thanks,
> > >> >> >> > Tim
> > >> >> >> >
> > >> >> >> > _______________________________________________
> > >> >> >> > Users mailing list
> > >> >> >> > Users at openser.org
> > >> >> >> > http://openser.org/cgi-bin/mailman/listinfo/users
> > >> >> >> >
> > >> >> >>
> > >> >> >>
> > >> >> >
> > >> >>
> > >> >>
> > >> >
> > >>
> > >>
> > >
> >
> >
>
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