per-user udev rules subset

[Stef Bon]

gibboris at gmail.com wrote:
>>
> DKD handle several mountpaths (char **), so does my code (comma separated) :
> if one of specified path matches one the mountpath of the newly mounted device
> (which I recall, can be mounted by automounter, user, root, udev, ...)
> The the value of DeviceMounted is execvp()
> ("mirage" is simple image viewer, I should have said that).
> The action may have been :
> ln -sf /mnt/pictures ~/.fuse/bind/Pictures
>
>   
OK! Before I continue, I try to explain how fuse-workspace works:

fuse-workspace mirrors the contents of $HOME/.fuse/bind. This is the 
first feature.
Second, it's possible to let a symbolic link look like a directory, 
which is a nice feature.

Two start:

mkdir -p $HOME/.fuse/bind/Devices

now when and usb stick is mounted by HAL (DeviceKit) at /media/USBstick, 
create a symlink like:

ln -sf /media/USBstick $HOME/.fuse/bind/Devices/USBstick

now mounting:

fuse-workspace $HOME/Workspace -o allow_root,use_ino

Now, at this moment it only mirrors:

ls -al $HOME/Workspace    gives

Devices

and

ls -al $HOME/Workspace/Devices    gives

lrwxrwxrwx           USBstick -> /media/USBstick

Now, this is already possible, making symlinks, so what's new?? Here the 
second feature:

after creating the directory in the "shadow" directory:

mkdir -p $HOME/Workspace/Devices/USBstick

the module fuse-workspace translates the symlink to a directory, so now 
a ls command gives:

ls -al $HOME/Workspace/Devices   gives

drwxr-xr-x             USBstick

This is actually a trick, workspace is folling you and the system.


> I remember having searched for a non-root bind -o, if it's possible with fuse-workspace,
> then the following theory should work :
> - plug happens
> - udev calls this script [1]
> - DKD is warned that plug happens (but not about mount)
> - DKD --monitor knows about mount, with my code it can trigger an event like :
> [catch-all mount rule]
> DeviceMounted=ln -sf %device_mount_paths ~/.fuse/bind/<something_variable_to_define>
> - the fuse-workspace daemon was already loaded, the bind is done
> My only problem with this is that I don't want my "known" mp3 player being given a generic
> name (or even it's LABEL) but being given specific mount path and access.
> So I need to find out how to make udev nicely ignore fstab configured device but that's another
> story.
>
> [1] http://en.gentoo-wiki.com/wiki/Autofs#Write_the_mount.2Funmount_scripts_2
>   

This is great! I know this link, I've created a simular contruction with 
autofs, launced by ConsoleKit and UDEV.

But about the order you've described above, and about the ability to 
have more than one mountpoint stored in the mount_point
property:

- plug happens
- DeviceKit (or autofs launched by udev at /mnt...) mounts the device at 
/media/USBstick
  DeviceKit sets the system mountpoint to /media/USBstick
- somehow (I do not know how) a symbolic link in $HOME/.fuse/bind/... 
and a directory in $HOME/.fuse/shadow... should be made for every logged
in user (which is also running a fuse-workspace instance) as shown above
- latest the  mountpoint property for  every user should be set to 
$HOME/Workspace/Devices/USBstick

As you may notice this only works if there is a difference between a 
system mountpoint (/media/USBstick)
and the mountpoints (like /home/sbon/Workspace/Devices/USBstick and 
/home/marian/Workspace/Hardware/USBstick)
should be exported to the environment of the different users, respect. 
sbon and marian.
Somehowe these different mountpoint should be stored and the environment 
(KDE or Gnome) should select the right mountpoint,
so /home/sbon/Workspace/Devices/USBstick should be taken by the 
(graphical) environment of sbon,
and simular for marian, you'll get the idea.

So per-user rules? Maybe, but sure per user mountpoints.

Stef