Arch Linux

kyku

Member

Registered: 2006-02-07

Posts: 24

Assign a group to removable devices.

How do I assign a custom group to newly created usb storage devices in /dev directory? I noticed they are added to "disk" group by default, but I'd like to have them in a different group than non-removable hard disks.

JuseBox

Member

Registered: 2009-11-27

Posts: 260

Re: Assign a group to removable devices.

https://wiki.archlinux.org/index.php/Ma … _with_udev

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kyku

Member

Registered: 2006-02-07

Posts: 24

Re: Assign a group to removable devices.

https://wiki.archlinux.org/index.php/Ma … _with_udev

Ok, so I created the file /etc/udev/rules.d/00.rules with the following contents:

SUBSYSTEM=="usb", KERNEL=="sd*", NAME="%k", GROUP="removable"

Then I told udev to reload it's rules with "udevadm control --reload-rules" and plugged in the pendrive. The files /dev/sdb* were not assigned to the 'removable' group, though.

cfr

Member

From: Cymru

Registered: 2011-11-27

Posts: 7,143

Re: Assign a group to removable devices.

Did you create the group removable?

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kyku

Member

Registered: 2006-02-07

Posts: 24

Re: Assign a group to removable devices.

Did you create the group removable?

Yes

kyku

Member

Registered: 2006-02-07

Posts: 24

Re: Assign a group to removable devices.

Ok, I managed to do it the following way. First of all I created file /etc/udev/rules.d/xx.rules (it looks like the rules are loaded and applied in alphabetical order, so I added this as the last one to override system defaults). The file contents is as follows:

ENV{ID_USB_DRIVER}="usb-storage", KERNEL=="sd*", GROUP="removable"

I used ENV{ID_USB_DRIVER} instead of SUBSYSTEM=="usb", because the latter didn't work.  Now some testing with:

$ sudo udevadm test $(udevadm info --query=path --name=/dev/sdb)
...
udev_rules_apply_to_event: GROUP 6 /lib/udev/rules.d/50-udev-default.rules:67
....
udev_rules_apply_to_event: GROUP 1000 /etc/udev/rules.d/xx.rules:1

6 is the id of arch's default disk group, 1000 of my new removable group. Voila...

All of the above was infered rather from experimenting than RTFMing so I you can do it better, please leave a comment.