#!/usr/bin/env bash
set -eu

/run/server.sh 5000 > /dev/null &

if /run/install.sh; then
  echo "Starting DSM for Docker..."
else
  echo "Installation failed (code $?)" && exit 80
fi

IMG="/storage"
FILE="$IMG/boot.img"
[ ! -f "$FILE" ] && echo "ERROR: Synology DSM boot-image does not exist ($FILE)" && exit 81

FILE="$IMG/system.img"
[ ! -f "$FILE" ] && echo "ERROR: Synology DSM system-image does not exist ($FILE)" && exit 82

FILE="$IMG/data.img"
if [ ! -f "$FILE" ]; then
    truncate -s "$DISK_SIZE" "$FILE"
    mkfs.btrfs -q -L data -d single -m single "$FILE" > /dev/null
    #qemu-img convert -f raw -O qcow2 -o extended_l2=on,cluster_size=128k,compression_type=zstd,preallocation=metadata "$TMP" "$FILE"
fi

[ ! -f "$FILE" ] && echo "ERROR: Synology DSM data-image does not exist ($FILE)" && exit 83

# A bridge of this name will be created to host the TAP interface created for
# the VM
QEMU_BRIDGE='qemubr0'

# DHCPD must have an IP address to run, but that address doesn't have to
# be valid. This is the dummy address dhcpd is configured to use.
DUMMY_DHCPD_IP='10.0.0.1'

# These scripts configure/deconfigure the VM interface on the bridge.
QEMU_IFUP='/run/qemu-ifup'
QEMU_IFDOWN='/run/qemu-ifdown'

# The name of the dhcpd config file we make
DHCPD_CONF_FILE='dhcpd.conf'

function default_intf() {
    ip -json route show |
        jq -r '.[] | select(.dst == "default") | .dev'
}

# First step, we run the things that need to happen before we start mucking
# with the interfaces. We start by generating the DHCPD config file based
# on our current address/routes. We "steal" the container's IP, and lease
# it to the VM once it starts up.
/run/generate-dhcpd-conf $QEMU_BRIDGE > $DHCPD_CONF_FILE
default_dev=$(default_intf)

# Now we start modifying the networking configuration. First we clear out
# the IP address of the default device (will also have the side-effect of
# removing the default route)
ip addr flush dev "$default_dev"

# Next, we create our bridge, and add our container interface to it.
ip link add "$QEMU_BRIDGE" type bridge
ip link set dev "$default_dev" master "$QEMU_BRIDGE"

# Then, we toggle the interface and the bridge to make sure everything is up
# and running.
ip link set dev "$default_dev" up
ip link set dev "$QEMU_BRIDGE" up

# Prevent error about missing file
touch /var/lib/misc/udhcpd.leases

# Finally, start our DHCPD server
udhcpd -I $DUMMY_DHCPD_IP -f $DHCPD_CONF_FILE 2>&1 &

# Start the Serial Emulator

HOST_SERIAL=$(/run/serial.sh)
GUEST_SERIAL=$(/run/serial.sh)

./run/serial.bin -cpu=1 \
		-buildnumber=42962 \
		-vmmts="1679863686" \
		-hostsn="$HOST_SERIAL" \
		-guestsn="$GUEST_SERIAL" \
		-vmmversion="2.6.1-12139" \
		-cpu_arch="QEMU, Virtual CPU, X86_64" \
		-guestuuid="ba13a19a-c0c1-4fef-9346-915ed3b98341" > /dev/null 2>&1 &

# Stop the webserver
pkill -f server.sh

[ ! -e /dev/net/tun ] && echo "Error: TUN interface not available..." && exit 85

if [ -e /dev/kvm ] && sh -c 'echo -n > /dev/kvm' &> /dev/null; then
  echo "Booting DSM image..."
else
  echo "Error: KVM not available..." && exit 86
fi

# Configure QEMU for graceful shutdown

QEMU_MONPORT=7100
QEMU_POWERDOWN_TIMEOUT=30

_graceful_shutdown() {

  local COUNT=0
  local QEMU_MONPORT="${QEMU_MONPORT:-7100}"
  local QEMU_POWERDOWN_TIMEOUT="${QEMU_POWERDOWN_TIMEOUT:-120}"

  set +e
  echo "Trying to shutdown gracefully.."

  # Send a NMI interrupt which will be detected by the agent
  echo 'nmi' | nc -q 1 localhost "${QEMU_MONPORT}">/dev/null 2>&1

  #echo 'system_powerdown' | nc -q 1 localhost "${QEMU_MONPORT}">/dev/null 2>&1
  echo ""

  while echo 'info version'|nc -q 1 localhost "${QEMU_MONPORT:-7100}">/dev/null 2>&1 && [ "${COUNT}" -lt "${QEMU_POWERDOWN_TIMEOUT}" ]; do
    (( COUNT++ )) || true
    echo "Shutting down, waiting... (${COUNT}/${QEMU_POWERDOWN_TIMEOUT})"
    sleep 1
  done

  if echo 'info version'|nc -q 1 localhost "${QEMU_MONPORT:-7100}">/dev/null 2>&1; then
    echo "Killing the VM.."
    echo 'quit' | nc -q 1 localhost "${QEMU_MONPORT}">/dev/null 2>&1 || true
  fi

  echo "Exiting..."
}

trap _graceful_shutdown SIGINT SIGTERM SIGHUP

# And run the VM! A brief explaination of the options here:
# -accel=kvm: use KVM for this VM (much faster for our case).
# -nographic: disable SDL graphics.
# -serial mon:stdio: use "monitored stdio" as our serial output.

exec qemu-system-x86_64 -name Synology -m "$RAM_SIZE" -enable-kvm -cpu host -nographic \
    -serial mon:stdio \
    -monitor telnet:localhost:"${QEMU_MONPORT:-7100}",server,nowait,nodelay \
    -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x3 \
    -chardev pty,id=charserial0 \
    -device isa-serial,chardev=charserial0,id=serial0 \
    -chardev socket,id=charchannel0,host=127.0.0.1,port=12345,reconnect=10 \
    -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=vchannel \
    -device virtio-net,netdev=tap0 -netdev tap,id=tap0,ifname=Tap,script="$QEMU_IFUP",downscript="$QEMU_IFDOWN" \
    -device virtio-scsi-pci,id=hw-synoboot,bus=pci.0,addr=0xa \
    -drive file="$IMG"/boot.img,if=none,id=drive-synoboot,format=raw,cache=none,aio=native,detect-zeroes=on \
    -device scsi-hd,bus=hw-synoboot.0,channel=0,scsi-id=0,lun=0,drive=drive-synoboot,id=synoboot0,bootindex=1 \
    -device virtio-scsi-pci,id=hw-synosys,bus=pci.0,addr=0xb \
    -drive file="$IMG"/system.img,if=none,id=drive-synosys,format=raw,cache=none,aio=native,detect-zeroes=on \
    -device scsi-hd,bus=hw-synosys.0,channel=0,scsi-id=0,lun=0,drive=drive-synosys,id=synosys0,bootindex=2 \
    -device virtio-scsi-pci,id=hw-userdata,bus=pci.0,addr=0xc \
    -drive file="$IMG"/data.img,if=none,id=drive-userdata,format=raw,cache=none,aio=native,detect-zeroes=on \
    -device scsi-hd,bus=hw-userdata.0,channel=0,scsi-id=0,lun=0,drive=drive-userdata,id=userdata0,bootindex=3 &

wait $!