How to quickly modify cups-pdf printer output folder setting?

Question

Longtime user of cups-pdf printer, I've always kept the default output folder setting: $HOME/PDF (or the identical /home/$USER/PDF).

Now I want to use a custom location for generated PDFs, but there is no output at all after modifying the config file (/etc/cups/cups-pdf.conf). Help?

Answer 1

The problem is with apparmor, not with cups or the virtual printer driver.

For any who want the convenience of 'one-touch' printing to pdf, the package can be installed by its older name:

sudo apt install cups-pdf

Or by the newer:

sudo apt install printer-driver-cups-pdf

Then to change the default output file destination, the config file may be edited:

sudo gedit /etc/cups/cups-pdf.conf (Use gksu or gksudo in place of sudo if preferred.)

On the line:

Out ${HOME}/PDF

Change the folder location as desired. Examples:

  Out ${HOME}/Desktop
  Out ${HOME}/print/pdfs
  Out /home/username/pdf

(If pasting an example line, use only one, like the original file.) Highlight the location part after the $, copy, then save the file and close it. Next, open the apparmor config file:

sudo gedit /etc/apparmor.d/usr.sbin.cupsd

Find the two lines near the bottom with the old default path, {HOME}/PDF

@{HOME}/PDF/ rw,
@{HOME}/PDF/* rw,

On each line, highlight everything between the @ and the trailing / and paste the new dirspec just copied. Inspect to be sure only the two paths were changed, and there are no missing or extra characters or spaces inserted. (Make a backup copy beforehand if unsure, and remember ctrlz undo is your friend.) Ex.

@{HOME}/Desktop/ rw,
@{HOME}/Desktop/* rw,

Save, close and reboot, then test print. Should work.

Answer 2

For those of you who have symlinked folders this will be helpful. In addition to setting up the above custom folder in /etc/cups/cups-pdf.conf do the following. In the 'K'Ubuntu 20.04 and above (the below explanation is implemented in Kubuntu 21.04), the default folder settings in the apparmor (/etc/apparmor.d/usr.sbin.cupsd) shouldn't be fiddled with. The defaults are good as below, retain them as is.

@{HOME}/[^.]*/{,**/} rw,
@{HOME}/[^.]*/**     rw,

In my case i have a separate ext4 partition /mnt/data/username for hosting the user directories such as Documents, Downloads, Music, Videos, Public, Templates, Pictures and VirtualBox VMs. I symlink these folders to /home/username/ example as below.

ln -s /mnt/data/username/Documents /home/username/Documents

So, for the cups-pdf print-to folder PDFs, i have mine in /mnt/data/username/Documents/PDFs.

My setup is as follows: in /etc/cups/cups-pdf.conf set

Out  ${HOME}/Documents/PDFs

in /etc/apparmor.d/usr.sbin.cupsd leave it at defaults. Run

sudo dpkg-configure apparmor

and in the dialog box that appears, add /mnt/data/ (note the trailing '/') as additional ${HOMEDIRS) and hit OK. That's all that needs done.

I need my userdirs in /mnt/data/username/ as i share the very same folders with ArchLinux Gnome40 install with the same username and UID/GID.

For reference and understanding why, see the following links:

http://manpages.ubuntu.com/manpages/trusty/en/man5/apparmor.d.5.html

https://www.mail-archive.com/[email protected]/msg1701831.html

https://www.mail-archive.com/[email protected]/msg1701828.html

https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/447292

https://forums.whonix.org/t/apparmor-exception-for-shared-folder-on-guess/656