This is my problem: I have a partition on my Ubuntu system, let's call it myhdrive, which is not automounted upon boot (so I use disk mounter applet, or Nautilus to mount it manually). When it is mounted, listing this partition looks like this in Ubuntu:
$ ls -la /media/myhdrive/
total 5743740
drwxr-xr-x 8 myusername myusername 4096 2011-07-21 08:19 .
drwxr-xr-x 4 root root 4096 2011-07-21 04:13 ..
-rw-r--r-- 1 myusername myusername 98520 2011-07-21 08:19 file1.txt
-rw-r--r-- 1 myusername myusername 3463 2011-07-21 08:19 file2.txt
Now, let's say I shutdown the Ubuntu OS - and boot, let's say, OpenSUSE from a USB key on the same machine. The myhdrive partition will again not be automounted, and then I have to mount it manually (again from the file manager there). The thing is, when mounted under OpenSUSE, the same drive displays the following listing:
$ ls -la /media/myhdrive/
total 5743740
drwxr-xr-x 8 1000 1000 4096 2011-07-21 08:19 .
drwxr-xr-x 4 0 0 4096 2011-07-21 04:13 ..
-rw-r--r-- 1 1000 1000 98520 2011-07-21 08:19 file1.txt
-rw-r--r-- 1 1000 1000 3463 2011-07-21 08:19 file2.txt
Obviously, myusername has uid of 1000 in the Ubuntu system, and there it is recognized - while the same username is not present in the OpenSUSE system, and so the uid is not replaced with a filename.
The problem is, of course, that I cannot write to the myhdrive from OpenSUSE by default - I'd first have to chown the entire partition - and then, when I get back to the Ubuntu system, I'd have to chown it back again.
It's quite clear to me that this will not be possible using the GUI tools - but is there a method or a command line switch, such that I can "fake ownership": mount this partition in such a way, that the real uid of 1000 is interpreted as 'the currently logged-in user' in the USB-booted case (including that, when writes are made to the partition by 'the currently logged-in user', they are recorded under the uid of 1000)?
Thanks in advance for any answers,
Cheers!
No. Either keep the authdb files in sync, or use an external auth server.