Path: utzoo!utgpu!water!watmath!clyde!att!ihnp4!ucbvax!XEROX.COM!"James_A._Gray.OsbuSouth"
From: "James_A._Gray.OsbuSouth"@XEROX.COM
Newsgroups: comp.os.vms
Subject: Re: Print symboints
Message-ID: <880526-223840-3902@Xerox>
Date: 27 May 88 05:37:58 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 81

Query:

Recently, while testing a new print symbiont, all of our batch and print
queues were deleted and the queue manager stopped.  The only thing we got
was a JOBCTL.DMP file in SYS$SYSTEM.  Contains only a condition signaled
as "%SYSTEM-F-PRIVINSTALL, shareable images must be installed to run privileged
image".  This was a modification to an existing symbiont (LASER, for the
Apple LaserWriter).  Since we obviously do not want to experience this
again (a lot of users were sure %^& mad at us!), does anyone have suggestions
as to what we can do?  The basic symbiont was written in C, but we added
subroutines written in Fortran if this impacts anything.

Also, does anybody know how to debug a print symbiont?  If it is compile/linked
in debug, it does seem to run.  Suggestions?

Some answers:

1)	When analyzing an image dump file from a different directory than 
	the image file you will always get the PRIVINSTALL message unless
	you specify the /IMAGE qualifier to point to the image file used to
	create the symbiont.  For example, assume that your image file is
	MYSYMBIONT.EXE and that it resides (as it must) in SYS$SYSTEM,
	then either

	$ SET DEFAULT SYS$SYSTEM
	$ ANALYZE/PROCESS MYSYMBIONT

	or

	$ ANALYZE/PROCESS/IMAGE=SYS$SYSTEM:MYSYMBIONT -
	SYS$SYSTEM:MYSYMBIONT

2)	To use the symbolic debugger with a user written symbiont, first
	compile with the /DEBUG qualifier, then link with the /DEBUG
	qualifier, redirect DBG$INPUT and DBG$OUTPUT to some real
	terminal and then finally start the symbiont.  For example,

	$ CC MYSYMBIONT/DEBUG
	$ LINK MYSYMBIONT/DEBUG
	$ COPY MYSYMBIONT.EXE SYS$SYSTEM:
	$ DBG_TERM = "OPA0:"
	$ DEFINE/NOLOG/TABLE=LNM$GROUP_000001 DBG$INPUT -
	'DBG_TERM'
	$ DEFINE/NOLOG/TABLE=LNM$GROUP_000001 DBG$OUTPUT -
	'DBG_TERM'
	$ DEFINE/NOLOG/TABLE=LNM$GROUP_000001 DBG$INIT -
	my-debug-init-file
	$ START/QUEUE queue-name/PROCESS=MYSYMBIONT

3)	The most likely cause of all of the queues being deleted (not really 
	deleted but not visible with a SHOW QUEUE) and the queue 
	manager stopping is a write to SYS$OUTPUT by the print symbiont.
	What actually happens is that JOBCTL takes a dive (usually you will
	get a JOBCTL.DMP in SYS$SYSTEM) which takes out the queue
	manager and all of the queues.  Just restarting the queue manager
	(via START/MANAGER) will get all of the queues back; sometimes
	it will complain that the queue file (JOBSYSQUE.DAT usually in 
	SYS$SYSTEM) is corrupted.  If JBSSYSQUE is corrupted then you will
	need to do a START/MANAGER/NEW and redefine all of your queues.

	If you need to output some message during the course of running
	the symbiont you should use either SYS$SNDOPR or SYS$BRKTHRU
	to output the message.  Never ever use SYS$OUTPUT, SYS$ERROR
	or SYS$INPUT in a symbiont.  A somewhat subtle way that you could
	be using one of these files would be by a routine signaling an error
	that is not handled by a condition handler; FORTRAN will do this
	for floating over/underflow for example.  You might want to set up a
	condition handler in the main that just exits with the error status;
	you'll get an OPCOM message that the symbiont exited but it will
	not affect other queues.

4)	When debugging a symbiont using the symbolic debugger, you may
	encounter the case where the debugger is entered without any
	message being reported.  This will be the case if the symbiont takes
	an access violation.  Just look at the current instruction and do a
	SHOW CALLS to find out where you are.

I hope that this is of some help.  If you're still having trouble, feel to
contact me directly.

	Jim Gray	Gray.OSBUSouth@Xerox.COM