Use floor division where floating point division was used

In Python 3 the division operator generates floats by default,
which could lead to unexpected crashes where integers were expected.
We changed the division operator to floor division operator, which has
the old behaviour from Python 2.

Change-Id: Iffed1383bbf4a025ef0a64bdb7664544e66ba6ea
Co-Authored-By: Claudiu Popa <cpopa@cloudbasesolutions.com>
Closes-Bug: #1494498

cloudbaseinit/metadata/services/osconfigdrive/windows.py

@@ -63,7 +63,6 @@ class WindowsConfigDriveManager(base.BaseConfigDriveManager):
 
     def _get_iso_disk_size(self, phys_disk):
         geom = phys_disk.get_geometry()
-
         if geom.MediaType != physical_disk.Win32_DiskGeometry.FixedMedia:
             return None
 
@@ -74,9 +73,9 @@ class WindowsConfigDriveManager(base.BaseConfigDriveManager):
         id_off = 1
         volume_size_off = 80
         block_size_off = 128
-        iso_id = 'CD001'
+        iso_id = b'CD001'
 
-        offset = boot_record_off / geom.BytesPerSector * geom.BytesPerSector
+        offset = boot_record_off // geom.BytesPerSector * geom.BytesPerSector
         bytes_to_read = geom.BytesPerSector
 
         if disk_size <= offset + bytes_to_read:
@@ -102,7 +101,7 @@ class WindowsConfigDriveManager(base.BaseConfigDriveManager):
             geom = phys_disk.get_geometry()
             offset = 0
             # Get a multiple of the sector byte size
-            bytes_to_read = 4096 / geom.BytesPerSector * geom.BytesPerSector
+            bytes_to_read = 4096 // geom.BytesPerSector * geom.BytesPerSector
 
             while offset < iso_file_size:
                 phys_disk.seek(offset)

cloudbaseinit/osutils/windows.py

@@ -381,12 +381,17 @@ class WindowsUtils(base.BaseOSUtils):
             raise exception.CloudbaseInitException(
                 "Setting password expiration failed: %s" % ex.args[2])
 
+    @staticmethod
+    def _get_cch_referenced_domain_name(domain_name):
+        return wintypes.DWORD(
+            ctypes.sizeof(domain_name) // ctypes.sizeof(wintypes.WCHAR))
+
     def _get_user_sid_and_domain(self, username):
         sid = ctypes.create_string_buffer(1024)
         cbSid = wintypes.DWORD(ctypes.sizeof(sid))
         domainName = ctypes.create_unicode_buffer(1024)
-        cchReferencedDomainName = wintypes.DWORD(
+        cchReferencedDomainName = self._get_cch_referenced_domain_name(
-            ctypes.sizeof(domainName) / ctypes.sizeof(wintypes.WCHAR))
+            domainName)
         sidNameUse = wintypes.DWORD()
 
         ret_val = advapi32.LookupAccountNameW(

cloudbaseinit/tests/metadata/services/osconfigdrive/test_windows.py

@@ -96,8 +96,8 @@ class TestWindowsConfigDriveManager(unittest.TestCase):
     @mock.patch('cloudbaseinit.metadata.services.osconfigdrive.windows.'
                 'WindowsConfigDriveManager._c_char_array_to_c_ushort')
     def _test_get_iso_disk_size(self, mock_c_char_array_to_c_ushort,
-                                media_type, value, iso_id):
+                                media_type, value, iso_id,
-
+                                bytes_per_sector=2):
         if media_type == "fixed":
             media_type = self.physical_disk.Win32_DiskGeometry.FixedMedia
 
@@ -115,7 +115,7 @@ class TestWindowsConfigDriveManager(unittest.TestCase):
         mock_geom.Cylinders = value
         mock_geom.TracksPerCylinder = 2
         mock_geom.SectorsPerTrack = 2
-        mock_geom.BytesPerSector = 2
+        mock_geom.BytesPerSector = bytes_per_sector
 
         mock_phys_disk.read.return_value = (mock_buff, 'fake value')
 
@@ -125,7 +125,7 @@ class TestWindowsConfigDriveManager(unittest.TestCase):
         disk_size = mock_geom.Cylinders * mock_geom.TracksPerCylinder * \
             mock_geom.SectorsPerTrack * mock_geom.BytesPerSector
 
-        offset = boot_record_off / mock_geom.BytesPerSector * \
+        offset = boot_record_off // mock_geom.BytesPerSector * \
             mock_geom.BytesPerSector
 
         buf_off_volume = boot_record_off - offset + volume_size_off
@@ -134,7 +134,6 @@ class TestWindowsConfigDriveManager(unittest.TestCase):
         response = self._config_manager._get_iso_disk_size(mock_phys_disk)
 
         mock_phys_disk.get_geometry.assert_called_once_with()
-
         if media_type != self.physical_disk.Win32_DiskGeometry.FixedMedia:
             self.assertIsNone(response)
 
@@ -173,7 +172,12 @@ class TestWindowsConfigDriveManager(unittest.TestCase):
             media_type="fixed",
             value=100, iso_id='other id')
 
-    def test_write_iso_file(self):
+    def test_test_get_iso_disk_size_bigger_offset(self):
+        self._test_get_iso_disk_size(
+            media_type="other media", value=100, iso_id='other id',
+            bytes_per_sector=2000)
+
+    def test_write_iso_file(self, bytes_per_sector=40):
         mock_buff = mock.MagicMock()
         mock_geom = mock.MagicMock()
         mock_geom.BytesPerSector = 2
@@ -187,10 +191,16 @@ class TestWindowsConfigDriveManager(unittest.TestCase):
         with mock.patch('six.moves.builtins.open', mock.mock_open(),
                         create=True) as f:
             self._config_manager._write_iso_file(mock_phys_disk, fake_path,
-                                                 10)
+                                                 4098)
-            f().write.assert_called_once_with(mock_buff)
+            f().write.assert_called_with(mock_buff)
-        mock_phys_disk.seek.assert_called_once_with(0)
+
-        mock_phys_disk.read.assert_called_once_with(10)
+        seek_calls = [mock.call(value) for value in range(0, 4098, 10)]
+        read_calls = (
+            [mock.call(4096)] +
+            [mock.call(value) for value in range(4088, 0, -10)]
+        )
+        self.assertEqual(seek_calls, mock_phys_disk.seek.mock_calls)
+        self.assertEqual(read_calls, mock_phys_disk.read.mock_calls)
 
     @mock.patch('os.makedirs')
     def _test_extract_iso_files(self, mock_makedirs, exit_code):

cloudbaseinit/tests/osutils/test_windows.py

@@ -237,7 +237,10 @@ class TestWindowsUtils(testutils.CloudbaseInitTestBase):
         sanitised = ' \\" '
         self.assertEqual(sanitised, response)
 
-    def _test_get_user_sid_and_domain(self, ret_val, last_error=None):
+    @mock.patch('cloudbaseinit.osutils.windows.WindowsUtils.'
+                '_get_cch_referenced_domain_name')
+    def _test_get_user_sid_and_domain(self, mock_cch_referenced,
+                                      ret_val, last_error=None):
         cbSid = mock.Mock()
         sid = mock.Mock()
         size = 1024
@@ -245,13 +248,14 @@ class TestWindowsUtils(testutils.CloudbaseInitTestBase):
         domainName = mock.Mock()
         sidNameUse = mock.Mock()
         advapi32 = self._windll_mock.advapi32
+        mock_cch_referenced.return_value = cchReferencedDomainName
 
         self._ctypes_mock.create_string_buffer.return_value = sid
         self._ctypes_mock.sizeof.return_value = size
-        self._wintypes_mock.DWORD.return_value = cchReferencedDomainName
         self._ctypes_mock.create_unicode_buffer.return_value = domainName
 
         advapi32.LookupAccountNameW.return_value = ret_val
+
         if ret_val is None:
             with self.assert_raises_windows_message(
                     "Cannot get user SID: %r",
@@ -267,6 +271,17 @@ class TestWindowsUtils(testutils.CloudbaseInitTestBase):
                 self._ctypes_mock.byref(cchReferencedDomainName),
                 self._ctypes_mock.byref(sidNameUse))
             self.assertEqual((sid, domainName.value), response)
+        mock_cch_referenced.assert_called_once_with(
+            self._ctypes_mock.create_unicode_buffer.return_value)
+
+    def test_get_cch_referenced_domain_name(self):
+        self._ctypes_mock.sizeof.side_effect = [42, 24]
+
+        result = self._winutils._get_cch_referenced_domain_name(
+            mock.sentinel.domain_name)
+
+        self._wintypes_mock.DWORD.assert_called_once_with(42 // 24)
+        self.assertEqual(result, self._wintypes_mock.DWORD.return_value)
 
     def test_get_user_sid_and_domain(self):
         fake_obj = mock.Mock()