Automount USB Drive in Runlevel 3

On a server at runlevel 3 (i.e. no monitor and X isn't running), it's sometimes nice to have usb drives automatically mounted.

A rule needs to be added to run a script whenever udev detects that a new drive has been inserted. Create the file /etc/udev/rules.d/99-usb-automount.rules containing:

KERNEL=="sd[a-z]?", RUN+="/usr/local/bin/usb_mount",
ENV{REMOVE_CMD}="/usr/local/bin/usb_mount"

Then add the script file /usr/local/bin/usb_mount containing:

#!/bin/bash
# $Id$
#
# Script to automaticlly mount usb devices.  This script is designed to work
# with udev
#

#commands used in the script
MOUNT="/bin/mount"
UMOUNT="/bin/umount -l"
MKDIR="/bin/mkdir -p"
RMDIR="/bin/rmdir"

#the root of where all auto mouted devices will be mounted to.
MOUNT_ROOT=/media
MNT_POINT=$MOUNT_ROOT/${DEVNAME##/dev/}

if [ -z "$ID_FS_TYPE" ]
then
logger "unidentified fs type: '$ID_FS_TYPE'"
exit 0
fi

logger "running $0"
logger "ACTION=$ACTION ID_BUS=$ID_BUS DEVNAME=$DEVNAME ID_FS_TYPE=$ID_FS_TYPE"

# check we are adding a usb device
if [ "$ID_BUS" != "usb" ]
then
logger "ignoring non usb device"
exit 0
fi

# check the action to process

case "$ACTION" in

add )

    logger "mounting new device"

    #create the directory we will mount to
    $MKDIR "$MNT_POINT"

    #
    #mount the usb device with the following options
    #
    #  ro           - read only
    #  noexec       - Do not allow direct execution of any binaries on the mounted file system
    #  nodev        - Do not interpret character or block special devices on the file system
    #
    #$MOUNT -t $ID_FS_TYPE $DEVNAME $MNT_POINT -o ro,noexec,nodev
    $MOUNT -t $ID_FS_TYPE $DEVNAME $MNT_POINT -o noexec,nodev

    #check if mount suceeded
    if [ $? -eq 0 ]
    then
    # sucess, we mounted ok.
      logger "mounted $DEVNAME at $MNT_POINT"
    else
    # we failed to mount so remove the mount point
      logger "failed to mount $DEVNAME at $MNT_POINT"
      $RMDIR "$MNT_POINT"
    fi
    ;;

remove )

    logger "unmounting existing device"

    # check if the device is really mounted
    #if [ (grep -q "^$DEVNAME" /proc/mounts || grep -q "^$DEVNAME" /etc/mtab) ]
    #then
    # logger "$DEVNAME not mouted"
    #endif

    #unmount the device.  We will refer using the mount point not the device name
    #becase there is a posibility the device could be removed before we
    #do the umount.
    $UMOUNT "$MNT_POINT"

    #remove the mount point
    $RMDIR "$MNT_POINT"

    logger "unmounted $DEVNAME and removed $MNT_POINT"
    ;;

* )
    logger "ignoring unkown action"
    ;;

esac