Bug#819288: /tmp is used before /tmp being mounted

[Anton Zinoviev <anton@lml.bas.bg>]

On Wed, Apr 13, 2016 at 11:52:44AM +0200, François Scala wrote:
> 
> While working on a Debian installation base on a ZFS root filesystem
> with LUKS encryption I've encountered a problem with keyboard-setup
> init script that create file in /tmp before /tmp being mounted.

Yes, keyboard-setup can attempt to create files in /tmp but it can do 
its job even when it is impossible to create a file there (because some 
other locations will be tried instead of /tmp).  There is some chance, 
however, that after keyboard-setup creates a temporary file in /tmp, 
/tmp gets mounted and the temporary file will no longer be accessible.

Fortunately, this is not a big problem, because temporary files will be 
used only if not everything necessary is prepared in /etc/console-setup.  
The other init script of console-setup -- /etc/init/console-setup(.sh) 
-- has the job to put in /etc/console-setup the necessary files.  This 
means that if you reboot the system, no files in /etc will be used.

I suppose I have to document in the man pages of /etc/default/keyboard 
and /etc/default/console-setup that the sysadmin has to run 

setupcon --save-only

if he edits some of these files and /tmp is in a separate file system.
 
> Here is the process tree
> 
>     |-keyboard-setup,1334 /etc/init.d/keyboard-setup start
>     |   `-setupcon,1336 /bin/setupcon -k
>     |       `-ckbcomp,1387 /usr/bin/ckbcomp -backspace del -model pc105 us

This information confirms that not all necessary files were present in 
/etc/console-setup.  Normally setupcon does not run ckbcomp and in the 
recent versions of console-setup (>=1.138) the keyboard-setup.sh init 
script does not run setupcon.

Anton Zinoviev