Ubuntu – Alert the user when they unsafely unplug an USB thumb drive

notify-sendudevunmountusb

Users repeatedly complain about lost data on USB thumb drives after they unplugged them without unmounting. We run Ubuntu 14.04 LTS on our machines. Auto-mounting is enabled.

As I am tired of remembering them to do a safe removal before unplugging, I want to make Ubuntu display an alert whenever a mounted USB drive is unplugged.

I thought of adding an udev rule that runs notify-send on removal in case the drive is still mounted. How can I determine if the USB drive was mounted upon removal?

Best Answer

I like Fabby's approach, but it is good to teach people about this bad habit (They are not working all the time on controlled machines). This is similar to an OSX feature, as described here.

There is a small difference that you may use it to know if it was a safe remove:

  • udev variable ID_PART_TABLE_TYPE=dos is set for sdx disk node (NOT partition node sdxY) in unsafe remove.

  • Where it is not set in safe remove

Noticed by monitoring udev events:

udevadm monitor -u --environment
  • Safe remove

    UDEV  [8292.380554] change   /devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.0/host16/target16:0:0/16:0:0:0/block/sdb (block)
    ACTION=change
    DEVLINKS=/dev/disk/by-id/usb-ADATA_USB_Flash_Drive_8d90ec535e6663-0:0 /dev/disk/by-path/pci-0000:00:14.0-usb-0:2:1.0-scsi-0:0:0:0
    DEVNAME=/dev/sdb
    DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2:1.0/host16/target16:0:0/16:0:0:0/block/sdb
    DEVTYPE=disk
    DISK_MEDIA_CHANGE=1
    ID_BUS=usb
    ID_INSTANCE=0:0
    ID_MODEL=USB_Flash_Drive
    ID_MODEL_ENC=USB\x20Flash\x20Drive\x20
    ID_MODEL_ID=c96a
    ID_PATH=pci-0000:00:14.0-usb-0:2:1.0-scsi-0:0:0:0
    ID_PATH_TAG=pci-0000_00_14_0-usb-0_2_1_0-scsi-0_0_0_0
    ID_REVISION=0.00
    ID_SERIAL=ADATA_USB_Flash_Drive_8d90ec535e6663-0:0
    ID_SERIAL_SHORT=8d90ec535e6663
    ID_TYPE=disk
    ID_USB_DRIVER=usb-storage
    ID_USB_INTERFACES=:080650:
    ID_USB_INTERFACE_NUM=00
    ID_VENDOR=ADATA
    ID_VENDOR_ENC=ADATA\x20\x20\x20
    ID_VENDOR_ID=125f
    MAJOR=8
    MINOR=16
    SEQNUM=2989
    SUBSYSTEM=block                                                              
    TAGS=:systemd:                                                               
    USEC_INITIALIZED=554873
    
  • Unsafe remove

    UDEV  [8391.320280] remove   /devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/host17/target17:0:0/17:0:0:0/block/sdb (block)
    ACTION=remove
    DEVLINKS=/dev/disk/by-id/usb-ADATA_USB_Flash_Drive_8d90ec535e6663-0:0 /dev/disk/by-path/pci-0000:00:14.0-usb-0:3:1.0-scsi-0:0:0:0
    DEVNAME=/dev/sdb
    DEVPATH=/devices/pci0000:00/0000:00:14.0/usb1/1-3/1-3:1.0/host17/target17:0:0/17:0:0:0/block/sdb
    DEVTYPE=disk
    ID_BUS=usb
    ID_INSTANCE=0:0
    ID_MODEL=USB_Flash_Drive
    ID_MODEL_ENC=USB\x20Flash\x20Drive\x20
    ID_MODEL_ID=c96a
    ID_PART_TABLE_TYPE=dos
    ID_PATH=pci-0000:00:14.0-usb-0:3:1.0-scsi-0:0:0:0
    ID_PATH_TAG=pci-0000_00_14_0-usb-0_3_1_0-scsi-0_0_0_0
    ID_REVISION=0.00
    ID_SERIAL=ADATA_USB_Flash_Drive_8d90ec535e6663-0:0
    ID_SERIAL_SHORT=8d90ec535e6663
    ID_TYPE=disk
    ID_USB_DRIVER=usb-storage
    ID_USB_INTERFACES=:080650:
    ID_USB_INTERFACE_NUM=00
    ID_VENDOR=ADATA
    ID_VENDOR_ENC=ADATA\x20\x20\x20
    ID_VENDOR_ID=125f
    MAJOR=8
    MINOR=16
    SEQNUM=3022
    SUBSYSTEM=block
    TAGS=:systemd:
    USEC_INITIALIZED=436355
    

  1. Create a udev rule (change useranme)

    $ sudo nano /etc/udev/rules.d/90-unsafe-remove-notify.rules
    
    ACTION=="remove", KERNEL=="sd?", ENV{ID_PART_TABLE_TYPE}!="", RUN+="/usr/bin/sudo -u username DISPLAY=:0 notify-send 'Unsafe Remove' '<b><i>Your long message</b></i>' -i /usr/share/icons/gnome/48x48/emotes/face-worried.png -t 10000"
    
  2. Reload rules

    sudo udevadm control --reload-rules
    

Another way, you may use a script (python) that connect to udisks DBUS. It has all needed info you need about partition mount/unmount, disks plug/unplug...

Reference/Source: Gentoo Wiki: Udisks - USB_Thumb_Drive_Example

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