Clean up TAP device name handling

entrypoint.sh

@@ -9,14 +9,16 @@ ip link set macvtap0 up
 
 # No udev in Docker
 IFS=: read major minor < <(cat /sys/devices/virtual/net/macvtap0/tap*/dev)
-mknod "/dev/tap$(cat /sys/class/net/macvtap0/ifindex)" c $major $minor
+DEV=/dev/tap$(cat /sys/class/net/macvtap0/ifindex)
+rm -fv $DEV
+mknod $DEV c $major $minor
 
 # Launch QEMU instance
 /usr/bin/qemu-system-x86_64 \
   -machine pc-i440fx-4.2,accel=kvm \
   -m 8192 \
   -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x6 \
-  -device virtio-net-pci,netdev=hostnet0,id=net0,mac=$(cat /sys/class/net/macvtap0/address) \
+  -device virtio-net-pci,netdev=hostnet0,id=net0,mac=$MAC \
   -device virtio-balloon-pci \
   -drive if=none,id=hd,file=/data/image.bin,snapshot=on,format=raw \
   -device scsi-hd,drive=hd \
@@ -24,4 +26,4 @@ mknod "/dev/tap$(cat /sys/class/net/macvtap0/ifindex)" c $major $minor
   -device usb-ehci,id=ehci                         \
   -device usb-tablet,bus=usb-bus.0 \
   -vnc :0 \
-  -netdev tap,id=hostnet0,vhost=on,fd=9 9<>/dev/tap$(cat /sys/class/net/macvtap0/ifindex)
+  -netdev tap,id=hostnet0,vhost=on,fd=9 9<>$DEV