virtme: kick udev when running as root

When running virtme-ng instances inside docker containers we may not
have a proper udev support on the host.

As a result the communication over virtio-serial port may not work
properly.

This can be solved by running the following command on the host (as
root), before starting the virtme-ng instances:

  # udevadm trigger --subsystem-match --action=change

Considering that we typicall run vng as root inside docker this can help
to automatically solve potential issues in this scenario.

This fixes issue #51.

Signed-off-by: Andrea Righi <[email protected]>

virtme/commands/run.py

@@ -1039,6 +1039,14 @@ def do_script(shellcmd: str, show_boot_console=False) -> None:
         kernelargs.extend(arch.earlyconsole_args())
         kernelargs.extend(console_args)
 
+        # Kick udev to make sure virtio-serial devices are correctly populated
+        # on the host.
+        #
+        # This action will be done only if running as root and this allows to
+        # to properly support virtme-ng instances running inside docker.
+        if os.geteuid() == 0:
+            os.system("udevadm trigger --subsystem-match --action=change")
+
         # Set up a virtserialport for script I/O
         #
         # NOTE: we need two additional I/O ports for /dev/stdout and