Re: Diskless print server

[Heinrich Rebehn <rebehn@comm.uni-bremen.de>]

Jim Hague wrote:
> 
> I hope this is appropriate for the list.
> 
> I've recently acquired an old 386 diskless box I'm booting with Etherboot
> into RH4.2 off a RH4.2 host. / is mounted via NFS from a client specific
> directory on the host. /usr is mounted ro directly from the host /usr, and
> /home is mounted rw directly from the host /home. I have not applied the
> swap via NFS patches, so there's no swap.
> 
> After customising /etc and /var, everything seems to be working OK. I've
> even configured XFree86 (slowww.....).
> 
> Well, almost everything. Printing doesn't work, which is a bit of a bugger
> as I want to use it as a print server. The printer is configured correctly,
> the spool directory exists with correct permissions, print jobs get spooled
> into it, and the print jobs are picked up by lpd and the input filter (if)
> is activated. At which point it all goes pear-shaped; when the filter tries
> to read stdin, the read fails and 'file: - no read permission' (or similar)
> appears on the console.
> 
> Needless to say, 'cat <queue file> | filter' works like a charm.
> 
> I suspect this is some sort of NFS artifact - surely if you didn't have
> read permission on the file the open would have failed? - but I'm running
> out of ideas. I even checked in case lpd was opening the spool file and
> then deleting it, as one thing I know would confuse NFS, but no.
> 
> Any suggestions? Has anybody out there done a diskless RH based print
> server?
> --
> Jim Hague - hague@research.canon.com.au(Work),bears@cix.co.uk(Play)
> Canon Information Systems Research Australia        +61 2 9805 2854

Hi,

I have had a similar problem with printing on a diskless machine using
PLP (Public Line Printer). The error message eas the same, although it
occured in an earlier stage - when lpd was trying to read the control
file on /tmp.
The reason was, that lpd did some filecopying like:

	become user1
	open source
	become user2
	open dest
	copy source to dest

The error occured when lpd tried to read source as user2. This does not
seem to be a problem on local filesystems, but does not work on NFS,
obviously NFS checks permission on every access, while on local fs only
the 'open' is checked.
Since we don't have elevated security needs, i simply deleted the
'become userx' stuff from the plp sources.
I did this about a year ago, and i tried to recall from memory what i
did, so the details may differ, but the basic behaviour was the same.

Hope this may help you,

Heinrich 


--
Heinrich Rebehn

University of Bremen
Physics / Electrical and Electronics Engineering
- Department of Telecommunications -

E-mail: mailto:rebehn@comm.uni-bremen.de
Phone : +49/421/218-4664
Fax   :            -3341