tools/qvm-create: resize root volume if needed before imporing data

If file to be imported is larger than the default root volume, resize
the volume first. It might be also a good idea to shrink it when needed,
but currently the backend refuse it.

Fixes QubesOS/qubes-issues#3422

qubesadmin/tests/tools/qvm_create.py

@@ -106,6 +106,12 @@ class TC_00_qvm_create(qubesadmin.tests.QubesTestCase):
             self.app.expected_calls[
                 ('new-vm', 'admin.vm.volume.List', None, None)] = \
                 b'0\x00root\nprivate\nvolatile\nkernel\n'
+            self.app.expected_calls[
+                ('new-vm', 'admin.vm.volume.Info', 'root', None)] = \
+                b'0\x00' \
+                b'pool=other-pool\n' \
+                b'vid=new-vm-root\n' \
+                b'size=10000000\n'
             self.app.expected_calls[
                 ('new-vm', 'admin.vm.volume.Import', 'root', b'root data')] = \
                 b'0\0'
@@ -128,6 +134,12 @@ class TC_00_qvm_create(qubesadmin.tests.QubesTestCase):
             self.app.expected_calls[
                 ('new-vm', 'admin.vm.volume.List', None, None)] = \
                 b'0\x00root\nprivate\nvolatile\nkernel\n'
+            self.app.expected_calls[
+                ('new-vm', 'admin.vm.volume.Info', 'root', None)] = \
+                b'0\x00' \
+                b'pool=other-pool\n' \
+                b'vid=new-vm-root\n' \
+                b'size=20000000\n'
             self.app.expected_calls[
                 ('new-vm', 'admin.vm.volume.Import', 'root', b'root data')] = \
                 b'0\0'
@@ -166,3 +178,35 @@ class TC_00_qvm_create(qubesadmin.tests.QubesTestCase):
             self.assertEqual(stdout.getvalue(),
                 'AppVM\nDispVM\nStandaloneVM\nTemplateVM\n')
         self.assertAllCalled()
+
+    def test_010_root_copy_from_with_resize(self):
+        with tempfile.NamedTemporaryFile() as root_file:
+            root_file.file.write(b'root data')
+            root_file.file.flush()
+            self.app.expected_calls[('dom0', 'admin.vm.Create.AppVM',
+                None, b'name=new-vm label=red')] = b'0\x00'
+            self.app.expected_calls[('dom0', 'admin.label.List', None, None)] = \
+                b'0\x00red\nblue\n'
+            self.app.expected_calls[('dom0', 'admin.vm.List', None, None)] = \
+                b'0\x00new-vm class=AppVM state=Halted\n'
+            self.app.expected_calls[
+                ('new-vm', 'admin.vm.volume.List', None, None)] = \
+                b'0\x00root\nprivate\nvolatile\nkernel\n'
+            self.app.expected_calls[
+                ('new-vm', 'admin.vm.volume.Info', 'root', None)] = \
+                b'0\x00' \
+                b'pool=other-pool\n' \
+                b'vid=new-vm-root\n' \
+                b'size=2\n'
+            self.app.expected_calls[
+                ('new-vm', 'admin.vm.volume.Resize', 'root', b'9')] = \
+                b'0\0'
+            self.app.expected_calls[
+                ('new-vm', 'admin.vm.volume.Import', 'root', b'root data')] = \
+                b'0\0'
+            qubesadmin.tools.qvm_create.main(['-l', 'red',
+                '--root-copy-from=' + root_file.name, 'new-vm'],
+                app=self.app)
+            self.assertAllCalled()
+            self.assertTrue(os.path.exists(root_file.name))
+

qubesadmin/tools/qvm_create.py

@@ -159,6 +159,9 @@ def main(args=None, app=None):
 
     if root_source_path:
         try:
+            root_size = os.path.getsize(root_source_path)
+            if root_size > vm.volumes['root'].size:
+                vm.volumes['root'].resize(root_size)
             with open(root_source_path, 'rb') as root_file:
                 vm.volumes['root'].import_data(root_file)
             if args.root_move_from: