Rewrite loader linux/initrd entry relabelling without regex to improv…

…e reliability

kiwi/bootloader/config/grub2.py

@@ -1459,22 +1459,27 @@ def _fix_grub_loader_entries_linux_and_initrd_paths(self):
         )
         for menu_entry_file in glob.iglob(loader_entries_pattern):
             with open(menu_entry_file) as grub_menu_entry_file:
-                menu_entry = grub_menu_entry_file.read()
-                if self.bootpartition:
-                    menu_entry = re.sub(
-                        r'(linux|initrd) .*/boot(.*)',
-                        r'\1 \2',
-                        menu_entry
-                    )
-                else:
-                    menu_entry = re.sub(
-                        r'(linux|initrd) .*(/boot.*)',
-                        r'\1 \2',
-                        menu_entry
-                    )
+                menu_entry = grub_menu_entry_file.read().split("\n")
+
+            for line_number, menu_entry_line in enumerate(menu_entry):
+                if bool(re.match(r'^(linux|initrd) .*', menu_entry_line)):
+
+                    log.debug("Existing loader entry: %s", menu_entry_line)
+                    config_path = menu_entry_line.split(" ",1)[0]
+
+                    basename = os.path.basename(menu_entry_line)
+                    if self.bootpartition:
+                        config_path += (" /%s" % basename)
+                    else:
+                        config_path += (" /boot/%s" % basename)
+
+                    menu_entry[line_number] = config_path
+                    log.debug("Updated loader entry: %s", config_path)
+
+            menu_entry = "\n".join(menu_entry)
             with open(menu_entry_file, 'w') as grub_menu_entry_file:
                 grub_menu_entry_file.write(menu_entry)
-
+                
     def _get_partition_start(self, disk_device):
         if self.target_table_type == 'dasd':
             blocks = self._get_dasd_disk_geometry_element(

test/unit/bootloader/config/grub2_test.py

@@ -1132,6 +1132,21 @@ def test_setup_install_image_config_substitute_error(self):
         with raises(KiwiTemplateError):
             self.bootloader.setup_install_image_config(self.mbrid)
 
+        self.bootloader.bootpartition = True
+        file_handle_menu.reset_mock()
+
+        self.bootloader.setup_disk_image_config(
+            boot_options={
+                'root_device': 'rootdev', 'boot_device': 'bootdev'
+            }
+        )
+
+        assert 'linux /vmlinuz' in \
+            file_handle_menu.write.call_args_list[1][0][0].split(os.linesep)
+        assert 'initrd /initrd' in \
+            file_handle_menu.write.call_args_list[1][0][0].split(os.linesep)
+
+
     @patch('kiwi.bootloader.config.grub2.Command.run')
     @patch('kiwi.bootloader.config.base.BootLoaderConfigBase.get_boot_path')
     @patch('os.path.exists')