#!/bin/sh

PREREQ=""
prereqs() {
	echo "$PREREQ"
}
case $1 in
# get pre-requisites
prereqs)
	prereqs
	exit 0
	;;
esac

USB_FUNCTIONS=rndis
ANDROID_USB=/sys/class/android_usb/android0
GADGET_DIR=/config/usb_gadget
LOCAL_IP=192.168.2.15
EXPLICIT_BUSYBOX="/bin/busybox"
TELNET_DEBUG_PORT=23

write() {
	echo -n "$2" >"$1"
}

# This sets up the USB with whatever USB_FUNCTIONS are set to via configfs
usb_setup_configfs() {
    G_USB_ISERIAL=$GADGET_DIR/g1/strings/0x409/serialnumber

    mkdir $GADGET_DIR/g1
    write $GADGET_DIR/g1/idVendor                   "0x18D1"
    write $GADGET_DIR/g1/idProduct                  "0xD001"
    mkdir $GADGET_DIR/g1/strings/0x409
    write $GADGET_DIR/g1/strings/0x409/serialnumber "$1"
    write $GADGET_DIR/g1/strings/0x409/manufacturer "Halium initrd"
    write $GADGET_DIR/g1/strings/0x409/product      "Failed to boot"

    if echo $USB_FUNCTIONS | grep -q "rndis"; then
        NETWORK_FUNCTION=""
        for function in ncm.usb0 rndis.usb0 rndis_bam.rndis; do
            if mkdir $GADGET_DIR/g1/functions/$function; then
                NETWORK_FUNCTION=$function
                break
            fi
        done

        if [ -z "$NETWORK_FUNCTION" ]; then
            echo "Error: No USB network gadget function available" >&2
            exit 1
        fi
    fi
    echo $USB_FUNCTIONS | grep -q "mass_storage" && mkdir $GADGET_DIR/g1/functions/storage.0

    mkdir $GADGET_DIR/g1/configs/c.1
    mkdir $GADGET_DIR/g1/configs/c.1/strings/0x409
    write $GADGET_DIR/g1/configs/c.1/strings/0x409/configuration "$USB_FUNCTIONS"

    if echo $USB_FUNCTIONS | grep -q "rndis"; then
        ln -s $GADGET_DIR/g1/functions/$NETWORK_FUNCTION $GADGET_DIR/g1/configs/c.1
    fi
    echo $USB_FUNCTIONS | grep -q "mass_storage" && ln -s $GADGET_DIR/g1/functions/storage.0 $GADGET_DIR/g1/configs/c.1

    echo "$(ls /sys/class/udc | grep -v dummy | head -1)" > $GADGET_DIR/g1/UDC
}

# This sets up the USB with whatever USB_FUNCTIONS are set to via android_usb
usb_setup_android_usb() {
    G_USB_ISERIAL=$ANDROID_USB/iSerial
    write $ANDROID_USB/enable          0
    write $ANDROID_USB/functions       ""
    write $ANDROID_USB/enable          1
    usleep 500000 # 0.5 delay to attempt to remove rndis function
    write $ANDROID_USB/enable          0
    write $ANDROID_USB/idVendor        18D1
    write $ANDROID_USB/idProduct       D001
    write $ANDROID_USB/iManufacturer   "Halium initrd"
    write $ANDROID_USB/iProduct        "Failed to boot"
    write $ANDROID_USB/iSerial         "$1"
    write $ANDROID_USB/functions       $USB_FUNCTIONS
    write $ANDROID_USB/enable          1
}

# This determines which USB setup method is going to be used
usb_setup() {
    mkdir /config || true
    mount -t configfs none /config || true

    if [ -d $ANDROID_USB ]; then
        usb_setup_android_usb $1
    elif [ -d $GADGET_DIR ]; then
        usb_setup_configfs $1
    fi
}

usb_info() {
    # make sure USB is settled
    echo "########################## usb_info: $1"
    sleep 1
    write $G_USB_ISERIAL "$1"
}

inject_loop() {
	INJ_DIR=/init-ctl
	INJ_STDIN=$INJ_DIR/stdin

	mkdir $INJ_DIR
	mkfifo $INJ_STDIN
	echo "This entire directory is for debugging init - it can safely be removed" >$INJ_DIR/README

	echo "########################## Beginning inject loop"
	while :; do
		while read IN; do
			if [ "$IN" = "continue" ]; then break 2; fi
			$IN
		done <$INJ_STDIN
	done
	rm -rf $INJ_DIR # Clean up if we exited nicely
	echo "########################## inject loop done"
}

usb_setup "halium-initrd telnet 192.168.2.15"

USB_IFACE=notfound
/sbin/ifconfig rndis0 $LOCAL_IP && USB_IFACE=rndis0
if [ x$USB_IFACE = xnotfound ]; then
	/sbin/ifconfig usb0 $LOCAL_IP && USB_IFACE=usb0
fi
# Report for the logs
/sbin/ifconfig -a

# Unable to set up USB interface? Reboot.
if [ x$USB_IFACE = xnotfound ]; then
	usb_info "Halium initrd Debug: ERROR: could not setup USB as usb0 or rndis0"
	dmesg
	sleep 60 # plenty long enough to check usb on host
	reboot -f
fi

# Create /etc/udhcpd.conf file.
echo "start 192.168.2.20" >/etc/udhcpd.conf
echo "end 192.168.2.90" >>/etc/udhcpd.conf
echo "lease_file /var/udhcpd.leases" >>/etc/udhcpd.conf
echo "interface $USB_IFACE" >>/etc/udhcpd.conf
echo "option subnet 255.255.255.0" >>/etc/udhcpd.conf

# Be explicit about busybox so this works in a rootfs too
echo "########################## starting dhcpd"
$EXPLICIT_BUSYBOX udhcpd

# Non-blocking telnetd
echo "########################## starting telnetd"
# We run telnetd on different ports pre/post-switch_root This
# avoids problems with an unterminated pre-switch_root telnetd
# hogging the port
$EXPLICIT_BUSYBOX telnetd -b ${LOCAL_IP}:${TELNET_DEBUG_PORT} -l /bin/sh

# For some reason this does not work in rootfs
usb_info "Halium initrd Debug telnet on port $TELNET_DEBUG_PORT on $USB_IFACE $LOCAL_IP - also running udhcpd"

ps -wlT
ps -ef
netstat -lnp
cat /proc/mounts
sync

# Run command injection loop = can be exited via 'continue'
inject_loop