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From Dean Gaudet <>
Subject Re: latest redhat rpm of apache
Date Fri, 02 Jan 1998 00:31:52 GMT
Martijn Koster mentioned that you can use:

    kill -0 "`cat /var/run/`"

But that can succeed while there's still a child hanging around... if we
used a process group we could use:

    kill -0 "-`cat /var/run/`"

Well, ok, actually we already use a process group.  So this already works.

Or rather, it works for some unixes but not others I'd guess.  Either
solution has portability concerns.  Everything modern should support both. 


On Thu, 1 Jan 1998, Dean Gaudet wrote:

> Actually when I mailed about the kill -9 problem he
> asked me if there was any way for him to know the daemon had died.
> I said there wasn't and was there another daemon that behaved in a way he
> liked 'cause I could emulate it.  He said nope, it's a general problem,
> a solution would be great.  So here's my proposed solution.
> After setting up the pid file the parent acquires a sharable lock on it.
> (The parent exits if the lock fails).  Each child also child acquires
> a sharable lock.  flock() or fcntl() will work for this.
> A support utility "waitlock filename timeout" attempts to acquire an
> exclusive lock on filename.  Once it has acquired the exclusive lock
> it exits with code 0.  On any error it exits with code 1, on timeout it
> exits with code 2.
> Then shutting down the server becomes:
>     kill -TERM `cat /var/run/`
>     waitlock /var/run/ 600
>     exit $?
> I suppose you could do kill -9, but I kinda hate doing that even in
> completely broken situations, especially in scripts.  "killall -9 httpd"
> could take out completely unrelated httpds.
> There's another use for this type of locking:  kill -USR1.  If you modify
> the children to all share lock the log files, then doing a waitlock
> after a rotation attempt will let you continue when all the children
> have completed.  But this still isn't as nice in my opinion as using a
> piped logger, because the piped logger can rotate immediately.
> But I think this is a nice way to know a signal has been received and
> processed.  An alternative is to use a control interface somewhat like
> INN does -- via a unix domain socket.
> Dean
> On Thu, 1 Jan 1998, Gregory A Lundberg wrote:
> > On Thu, 1 Jan 1998, Marc Slemko wrote:
> > 
> > > Does it compress the logs at all?
> > 
> > Compress 'em?  Be glad they finally fixed the signals.  They still rotate
> > Samba logs without signalling causing the files to grow with zillions of
> > NUL bytes at the front.
> > 
> > ----
> > 
> > Gregory A Lundberg		Senior Partner, VRnet Company
> > 1441 Elmdale Drive              email: []
> > Kettering, OH 45409-1615 USA    voice: +1 (937) 299-7653
> > 
> > 

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