No SIGUP for xinetd? Was: [H-GEN] Web page creation on windows, serving on linux

[ben.carlyle at invensys.com]

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Hello,





Harry Phillips <hphillips at myaccess.com.au>
Sent by: Majordomo <majordom at caliburn.humbug.org.au>
18/07/03 12:11
Please respond to general

 
        To:     general at lists.humbug.org.au
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        Subject:        Re: [H-GEN] Web page creation on windows, serving on linux


> Greg Black wrote:
> > 
> > On most systems, you then need to tell inetd that things have
> > changed.  On most modern Unix systems with a modern /bin/sh, the
> > following incantation, as root, will do it:
> > 
> >     kill -1 $(cat /var/run/inetd.pid)
> > 
> > I don't use xinetd[1], so I won't comment on that case.
> > 

> When you use xinetd you edit the file /etc/xinetd.d/proftp-xinetd file 
> and there is no need for doing the kill -1... thingy.

Uhhh, really?

I wondered whether this could actually be true (I don't have xinetd on my 
machine so can't test it easily myself), so I looked up an online version 
of the man page. According to this page a SIGHUP "... causes a hard 
reconfiguration, which means that xinetd re-reads the configuration file 
and terminates the servers for services not longer available". Does it 
really work if you don't SIGHUP it?

The reason I ask is because inetd normally has to keep a socket listening 
for every service it opens. Without re-reading the config it wouldn't know 
which sockets to open, and therefore wouldn't be able to accept 
connections on behalf of the service it intends to start. It could 
periodically check its files to see if they're changed, but that seems 
broken. What if you're still editing the file when it checks? I notice a 
speel on this page about TCPMUX, which appears to use a single port for 
all services and sends a message on connection indicating which service it 
actually wants. Is this what you're using? Hmm... that seems like a broken 
idea to me.

Please feel free to alleviate my confusion :)

Benjamin.


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