[cups] unable to open file | permission denied

[Evan Cooch]

A quick search tells me I'm running into a fairly common problem, but 
said search also shows there is a real paucity of general solutions/fixes.

I'm running CUPS 1.4.2 under RHEL 6.x. Added a printer (Ricoh Aficio) 
using vendor-supplied PPD.  However, whenever I try to print  a (almost 
exclusively PDF) file (either as root, or allowed user), the print job 
gets dumped into /var/spool/cups, and I get an error message of the 
following type:

/"Unable to open file "/var/spool/cups/d00034-001" - Permission denied"


/Permissions on /var/spool/cups are

drwx--x---.  3 root  lp    4096 May 15 11:54 cups


If I look in /var/spool/cups, the file (d00034-001) is there, with the 
same owner (root) and grp (lp)


ps -aux | grep cups

shows its running as root.

More tellingly, perhaps (although I don't know what this has to do with 
'permissions') is that in /usr/var/cups/error_log, I see the following

Cannot process "<STDIN>": Unknown filetype


Taking that as a clue, I tried printing from the command line:


lp test.pdf

Error now is

stopped: "Empty print file".


At this point, I'm out of options for 'self-help' based on my limited 
knowledge of CUPS.

Any advice/suggestions/pointers to the obvious appreciated.