hostname.sh

#!/bin/sh

url="rigadogateway.com"

get_fuse () {
    local name=$1
    local pad=$2
    # read the fuse and pad the left with zeros to the size of $pad
    local fuse="00000"$(cat /sys/fsl_otp/$name | cut -b 3-)
    len=$(( ${#fuse} - $pad ))
    echo ${fuse:$len}
}

get_sn () {
    local base=$1
    local arena=$(get_fuse HW_OCOTP_GP$base 7)
    if [[ ${arena:0:2} == "00" ]] ; then
    	# starts with "00", so doesn't start with ascii hex value
        arena=${arena:2}
    else
    	# doesn't start with "00", so starts with ascii hex value
        arena=$(printf "\x${arena:0:2}${arena:2}")
    fi

    local build=$(get_fuse HW_OCOTP_GP$(( $base + 1)) 4)
    local unit=$(get_fuse HW_OCOTP_GP$(( $base + 2)) 5)

    echo "$arena$build-$unit"
}

if [[ "$(cat /sys/fsl_otp/HW_OCOTP_GP37)" == "0x0" ]] ; then
    # No unit serial number set, use board serial number
    hostname $(get_sn 34).$url
else
    # unit serial number set, use it
    hostname $(get_sn 37).$url
fi