tinyramfs/device-helper

#!/bin/sh -f
#
# create /dev/disk/by-* and /dev/mapper/* symlinks

create_symlink()
{
    sym="$1"
    sym="${sym%\"}"
    sym="${sym#\"}"
    sym="${dir}${sym}"

    mkdir -p "$dir" 2> /dev/null
    ln    -s "/dev/${MDEV}" "$sym" 2> /dev/null
}

# int main()
{
    [ "$MDEV" ] || exit 1

    for line in $(blkid "$MDEV"); do case "${line%%=*}" in
        UUID)
            dir="/dev/disk/by-uuid/"
            create_symlink "${line##*=}"
        ;;
        LABEL)
            dir="/dev/disk/by-label/"
            create_symlink "${line##*=}"
        ;;
        PARTUUID)
            dir="/dev/disk/by-partuuid/"
            create_symlink "${line##*=}"
        ;;
    esac; done

    [ -e "/sys/block/${MDEV}/dm/name" ] && {
        mkdir -p /dev/mapper 2> /dev/null
        read  -r name < "/sys/block/${MDEV}/dm/name"
        ln    -s "/dev/${MDEV}" "/dev/mapper/${name}" 2> /dev/null
    }
}