docker.py: add --run-as-current-user

(podman will need further tweaks)

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

tests/docker/Makefile.include

@@ -212,7 +212,7 @@ docker-run: docker-qemu-src
 			"  COPYING $(EXECUTABLE) to $(IMAGE)"))
 	$(call quiet-command,						\
 		$(DOCKER_SCRIPT) run 					\
-			$(if $(NOUSER),,-u $(shell id -u)) 		\
+			$(if $(NOUSER),,--run-as-current-user) 		\
 			--security-opt seccomp=unconfined		\
 			$(if $V,,--rm) 					\
 			$(if $(DEBUG),-ti,)				\

tests/docker/docker.py

@@ -333,8 +333,13 @@ class RunCommand(SubCommand):
     def args(self, parser):
         parser.add_argument("--keep", action="store_true",
                             help="Don't remove image when command completes")
+        parser.add_argument("--run-as-current-user", action="store_true",
+                            help="Run container using the current user's uid")
 
     def run(self, args, argv):
+        if args.run_as_current_user:
+            uid = os.getuid()
+            argv = [ "-u", str(uid) ] + argv
         return Docker().run(argv, args.keep, quiet=args.quiet)