Bug#401405: [Pkg-cups-devel] Bug#401405: bogus error message with ownership problems

[Ulrich Eckhardt]

On Sunday 03 December 2006 15:31, Kenshi Muto wrote:
> I understand CUPS provides not enough messages. It has to be improved
> more in the future.

I've been poking around some more, and I found some more strange things. I 
increased the log-level to debug2 (i.e. "log everything") and it doesn't even 
show an error there! The error is only displayed in the webfrontend. I also 
couldn't find how the USB backend is called from the logfiles, in the most 
verbose mode I would have expected to find the arguments passed to the 
executable.

> Well, let's think about /dev/usb/lp0 permission problem at this time.
> As far as I know CUPS backend will run as ownership root:root or lp:lp.
> USB backend will run as lp:lp, so it should be able to access
> /dev/usb/lp0.
>
> If your machine is i386 architecture, could you replace /usr/lib/cups/
> backend/usb by http://kmuto.jp/tmp/usb-debug.tar.gz ?
> After then, try to print something to your USB printer.
> You'll see the result of ownership check at /tmp/o2 file.

Did so, the content of the file says

  uid=7(lp) gid=0(root) groups=0(root)

HTH

Uli