#!/bin/sh
# Create alias for modem interface, based on its IMEI and sim ICCID
# Script version 1.03 Rafal Drzymala 2013
#
# Changelog
#     1.00    RD    First stable code
#    1.01    RD    Added additional USB device filter (suggested by Obsy)
#    1.02    RD    Added ICCID decode to readable format
#    1.03    RD    Changed communication with modem
#
# Destination /etc/hotplug.d/usb/90-modem_aliases
#

do_modem_cmd() {
    local Device=$1
    local Cmd=$2
    printf "\nATQ0V1E1\nAT$Cmd\n" >$Device 2>/dev/null
    sleep 1
    awk '
    BEGIN {
        FS="\n";
        RS="\n";
        Step=1;
        Response="";}
    {    if ($1!="") print $1 >>"/tmp/modem_aliases";
        if ($1=="" || substr($1,1,11)=="^")
            {}
        else if ($1=="COMMAND NOT SUPPORT" || $1=="ERROR" || substr($1,1,11)=="+CME ERROR:")
            exit 1
        else if (Step==1 && $1=="OK")
            Step=2
        else if (Step==2 && $1=="AT'$Cmd'") 
            Step=3
        else if (Step==3 && $1!="" && $1!="OK")
            { Step=4; Response=$1 }
        else if (Step==4 && $1=="OK") 
            exit}
    END {
        print Response}' $Device 2>/dev/null
}

get_modem_IMEI() {
    local IMEI=$(do_modem_cmd $1 "+CGSN")
    case "$IMEI" in
    [0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]) echo "$IMEI";;
    esac
}

get_sim_ICCID() {
    local ICCID=$(do_modem_cmd $1 "+CRSM=176,12258,0,0,10" | cut -d "," -f 3 | tr -d "\"")
    local ICCID=$(echo "${ICCID:1:1}${ICCID:0:1}${ICCID:3:1}${ICCID:2:1}${ICCID:5:1}"\
"${ICCID:4:1}${ICCID:7:1}${ICCID:6:1}${ICCID:9:1}${ICCID:8:1}${ICCID:11:1}${ICCID:10:1}"\
"${ICCID:13:1}${ICCID:12:1}${ICCID:15:1}${ICCID:14:1}${ICCID:17:1}${ICCID:16:1}${ICCID:19:1}")
    case "$ICCID" in
    [0-9][0-9][0-9][0-9]*) echo "$ICCID";;
    esac
}

create_device_alias() {
    local DevicePath=$1
    local InterfaceAlias=$2
    if [ -L $InterfaceAlias ] && [ $(ls -l $InterfaceAlias | awk '{print $11}') != $DevicePath ]; then
        logger -p user.notice -t $SCR "$DEVICENAME Remove link $InterfaceAlias for device $DevicePath"
        rm -f $InterfaceAlias
    fi
    if [ ! -L $InterfaceAlias ]; then
        logger -p user.notice -t $SCR "$DEVICENAME Create link $InterfaceAlias for device $DevicePath"
        ln -sf $DevicePath $InterfaceAlias
    fi
}

cleanup_devices_aliases() {
    local DeviceInfo
    for DeviceInfo in $(ls -l /dev/*i? | awk '$9!="" && $11!="" {print $9":"$11}'); do
        local InterfaceAlias=$(echo "$DeviceInfo" | cut -d ":" -f 1)
        local DevicePath=$(echo "$DeviceInfo" | cut -d ":" -f 2)
        if [ ! -c $DevicePath ]; then
            logger -p user.notice -t $SCR "$DEVICENAME Remove link $InterfaceAlias for device $DevicePath"
            rm -f $InterfaceAlias
        fi
    done
}

if [ "$HOTPLUG_TYPE" == "usb" ] && [ "$DEVTYPE" == "usb_interface" ]; then
    case "$DEVICENAME" in
    *-*.*:*.*) : ;;
    *-*:*.*) : ;;
    *) exit 0 ;;
    esac
    SCR=$(basename $0)
    if [ "$ACTION" == "add" ]; then
        if [ -e /sys$DEVPATH/*/tty/*/dev ]; then
            local ModemIMEI
            local simICCID
            for InterfaceConfig in /sys$DEVPATH/../*/*/tty/*; do
                local InterfaceNumber=$(cut -d ':' -f 2 $InterfaceConfig/dev)
                if [ "$InterfaceNumber" != "" ]; then
                    local ModemDevice=/dev/$(basename $InterfaceConfig)
                    [ -c $ModemDevice ] && [ "$ModemIMEI" == "" ] && ModemIMEI=$(get_modem_IMEI $ModemDevice)
                    if [ "$ModemIMEI" != "" ]; then
                        local InterfaceAlias=/dev/"mdm"$ModemIMEI"i"$InterfaceNumber
                        create_device_alias $ModemDevice $InterfaceAlias
                    fi
                    [ -c $ModemDevice ] && [ "$simICCID" == "" ] && simICCID=$(get_sim_ICCID $ModemDevice)
                    if [ "$simICCID" != "" ]; then
                        local InterfaceAlias=/dev/"sim"$simICCID"i"$InterfaceNumber
                        create_device_alias $ModemDevice $InterfaceAlias
                    fi
                fi
            done
        fi
    elif [ "$ACTION" == "remove" ]; then
        cleanup_devices_aliases
    fi
fi
#Done