ppr-list-digest volume 3, number 35, message 2

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From: David Chappell <David.Chappell@mail.trincoll.edu>
Date: Wed, 14 Mar 2001 12:04:22 -0500
Subject: Re: PPR: What if disk is full and various questions...

Alain.Lachapelle@Heimannsystems.Com wrote:

> Hi again,
> 
>   I'd like to know the behaviour of ppr when there is not enough space in
> the /var/spool/ppr area to process a new print job.  Will ppr return an
> appropriate error?

Disk full handling in Standard C's stdio isn't very good, yet ppr (the 
command) tries to detect disk full.  If the disk fills when enqueueing 
the job, it is discarded and ppr returns a non-zero exit code.

> 
>   Most of the discs on our systems are read-only.  What I see the
> read-write space needed  for ppr are the /var/spool/ppr and the /etc/ppr/
> areas.  Is it possible to narrow the read-write disk spaces to:
> 
>      /var/spool/ppr/jobs
>      /var/spool/ppr/queue
> 
>      and
> 
>      /etc/ppr/printers.
> 
>   Are there any other read-write disk space required ?

While an attempt has been made to divide the parts of PPR properly to 
limit the size of the read-write space, there are still some stray 
ends.  For example, the execute bits on the files in /etc/ppr/printers 
are used to remember the printer status.  There are still a few other rw 
files /etc/ppr.  As best I recall they are /etc/ppr/groups/*, 
lw-messages.conf, and charge_users.db.

The plan is to move everything read-write into /var/spool/ppr.  
Presently there is _nothing_ in /var/spool/ppr that can be read-only 
except for drivers/ which really should be moved to /usr/share/ppr.  
These rw files include pid files, a named pipe, logs, and a font cache.

Note that if your application is limited, such as printing from an 
embedded application, most of these files won't be a problem because 
they won't be used. If lw-messages.conf is read-only, probably nothing 
bad will happend.  If you aren't using ppuser, then you don't even need 
charge_users.db.  If you aren't using Macintosh clients, the font cache 
won't be populated.

I know this is a little unclear.  That is because I haven't yet gotten 
to the point of doing an audit.  If you have questions about a specific 
file or directory, write to me directly and I will tell you what I know.