udev script and rules for automounting a disk under /media/ with its label

storage.sh

#!/bin/bash

# This file goes in /lib/udev/storage.sh
# Based on http://superuser.com/a/630937

# A matching /etc/udev/rules.d/85-storage-automount.rules should contain:
# ENV{DEVTYPE}=="partition", ENV{DEVNAME}!="/dev/mmcblk0p?", PROGRAM="/lib/udev/storage.sh mountpoint", ENV{MOUNTPOINT}="$result"
# ENV{MOUNTPOINT}!="", ACTION=="add", RUN+="/lib/udev/storage.sh add $env{MOUNTPOINT}"
# ENV{MOUNTPOINT}!="", ACTION=="remove", RUN+="/lib/udev/storage.sh remove $env{MOUNTPOINT}"

# Note that the ENV{DEVNAME}!="/dev/mmcblk0p?" above is for the Raspberry PI's SD boot device.
# This doesn't solve the problem of disks that share the same label.  I don't think this can be cleanly done with udev alone.

MOUNT_BASE='/media/'
MOUNT_USER=root
MOUNT_GROUP=plugdev
MOUNT_OPTIONS=rw,flush,user,umask=002,dmask=002,fmask=002 # Other options (breaks POSIX): noatime,nodiratime,nosuid,nodev
UNSAFE_CHARS='\0-\037\041-\057\072-\100\133-\140\173-\177'

case $1 in
        mountpoint)
                # Pick the mountpoint name according to partition or device name
                dir="$(echo "$ID_FS_LABEL" | tr "$UNSAFE_CHARS" _ | sed -e 's/^_*//' -e 's/_*$//')"
                if [ -z "$dir" ]; then
                        dir="${DEVNAME##*/}"
                fi

                if [ -n "$dir" ]; then
                        # Make available to rules
                        echo "$MOUNT_BASE$dir"
                fi
        ;;
        add)
                mkdir -p "$2"
                chown $MOUNT_USER:$MOUNT_GROUP "$2"

                uid=$(id -u $MOUNT_USER)
                gid=$(grep $MOUNT_GROUP /etc/group|cut -f3 -d:)
                mount -t "$ID_FS_TYPE" -o "$MOUNT_OPTIONS,uid=${uid-0},gid=${gid-0}" $DEVNAME "$2"
        ;;
        remove)
                umount -l $2
                rmdir $2
        ;;
esac