IW=/usr/sbin/iw

if [ ! -x $IW ]; then
    log "VERBOSE" "No $IW program, WiFi power setting is disabled."
elif [ x$CONTROL_WIFI_POWER = x1 ] ; then
    if [ $ON_AC -eq 1 ] ; then
        power_mgmt="off"
    else
        power_mgmt="on"
    fi

    for DEVICE in /sys/class/net/* ; do
        if [ -d $DEVICE/phy80211 ]; then
            dev=`basename $DEVICE`
            $IW $dev set power_save $power_mgmt
            ret=$?
            if [ "$ret" = "0" ]; then
               log "VERBOSE" "Power Management set to $power_mgmt for $dev."
            else
                log "VERBOSE" "Failed to set Power Management to $power_mgmt for $dev."
            fi
        fi
    done
else
    log "VERBOSE" "WiFi power setting is disabled."
fi