RE: [Handle-info] Starting and stopping the handle server from Unix rc scripts [SEC=UNCLASSIFIED]

["Chadwick, Philip" <Philip.Chadwick@environment.gov.au>]

Hi Andy,

Thank you.  Also to Mike and Robert for helpful replies.

I'm at a small disadvatage, since I don't actually run the handle server
yet.

Also, I am no Java expert.  I asked about Java Service Wrappers because
I have never used them and have more questions than answers at this
time.  I intend to investigate.

My question related to the usual need for a daemon to detatch from the
controlling terminal (/dev/console for rc start scripts), and become
group leader of a new process group with a new session ID, all of which,
it seems, is beyond the normal scope of Java applications.  You can't
have a reliable daemon if you don't do these things!

Section 2.5 of the Handle.Net Technical Manual (version 6.2) says about
starting the server:

    "Note: If you chose to encrypt your private key(s), you will be
prompted for your passphrase here. Also note that Java (TM) does not
have the ability to disconnect from a    terminal so you will have to
put the process in the background. On Unix systems type Ctrl Z, then bg,
then press ENTER."

I must admit some deflation when I realised that the authors of the
handle server expected it to have it's very own operator on call 24x7.
It has not been daemonised.  Nor are there recommendations in the manual
on how to do that.  Sigh...

For unattended booting, we won't be encrypting the (administrator's ?)
private key, because we don't want the handle server to stall on input,
ever.

I expect that the start/stop scrips posted leave the handle server
attached to /dev/console as the controlling terminal after boot (or what
ever tty was last used to start the server).  That means it will get
signals directed at an inherited process group (rather than its own,
private, process group).  Very undesirable, and will cause the server to
die unexpectedly (usually from SIGHUP when somebody logs out) in
aparently bizzare ways.

A quick look at the handle server code shows it uses the swing
libraries, which require a frame buffer display.  I expect that the
start/stop scrips posted are using the console hardware frame buffer.  I
also expect that they would fail if there were no hardware frame buffer.

I think that the correct way to create the start/stop scripts is to use
a C program as wrapper [exactly the same as FreeBSD daemon(8)] to
daemonise [see daemon(3) on Linux] before invoking the handle server
with the DISPLAY pointed at a virtual frame buffer (Xvfb).  The key part
of the start script would be:

  DISPLAY=":2.0"; export DISPLAY	# you need to previously start
"Xvfb :2"
  daemon -u handleuser $JAVA net.handle.server.Main /usr/local/hs/data
1>server.log 2>&1 &

This is all theory.  I don't know how the java interpreter will react to
being daemonised.  When I get the handle server code running, I'll port
FreeBSD daemon(8) to Linux and run some trials.

Cheers,

-- 
Phil


-----Original Message-----
From: Andy Stevens [mailto:stevens@electricalscience.com] 
Sent: Wednesday, 28 July 2010 11:47 PM
To: Chadwick, Philip
Subject: Re: [Handle-info] Starting and stopping the handle server from
Unix rc scripts [SEC=UNCLASSIFIED]

Philip, attached is a start/stop script for the Handle server that I've
been using for many years on Red Hat Linux.  It goes in /etc/init.d and
should be symlinked from the appropriate boot script dir.

Regards,

--Andy Stevens


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