Fix mbrid setup for read-only systems

On filesystems without a UUID (e.g squashfs) the fallback boot id setup should apply if neither UUID nor MBR ID is present. This is a followup fix for Issue #2391
OSInside · Nov 10, 2023 · 7f64e7a · 7f64e7a
1 parent 7447203
commit 7f64e7a
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Showing 2 changed files with 24 additions and 5 deletions.
diff --git a/kiwi/bootloader/config/grub2.py b/kiwi/bootloader/config/grub2.py
@@ -893,7 +893,7 @@ def _setup_efi_image(
                 uuid, mbrid, lookup_path
             )
 
-    def _setup_bios_image(self, mbrid=None, lookup_path=None):
+    def _setup_bios_image(self, mbrid, lookup_path=None):
         """
         Provide bios grub image
         """
@@ -1020,7 +1020,7 @@ def _create_efi_config_search(self, uuid=None, mbrid=None):
                 efi_boot_config, mbrid
             )
 
-    def _create_bios_image(self, mbrid=None, lookup_path=None):
+    def _create_bios_image(self, mbrid, lookup_path=None):
         early_boot_script = os.path.normpath(
             os.sep.join([self._get_grub2_boot_path(), 'earlyboot.cfg'])
         )
@@ -1116,9 +1116,15 @@ def _create_early_boot_script_for_mbrid_search(self, filename, mbrid):
             early_boot.write(
                 'set btrfs_relative_path="yes"{0}'.format(os.linesep)
             )
-            early_boot.write(
-                f'search --file --set=root /boot/{mbrid.get_id()}{os.linesep}'
-            )
+            if mbrid:
+                early_boot.write(
+                    f'search --file --set=root /boot/{mbrid.get_id()}{os.linesep}'
+                )
+            else:
+                # Fallback search for /boot/mbrid
+                early_boot.write(
+                    f'search --file --set=root /boot/mbrid{os.linesep}'
+                )
             early_boot.write(
                 'set prefix=($root)/boot/{0}{1}'.format(
                     self.boot_directory_name, os.linesep

diff --git a/test/unit/bootloader/config/grub2_test.py b/test/unit/bootloader/config/grub2_test.py
@@ -1902,6 +1902,19 @@ def side_effect(arg):
             )
         ]
 
+        with patch('builtins.open', create=True) as mock_open:
+            # Test fallback search for earlyboot if UUID and MBR ID are missing
+            mock_open.return_value = MagicMock(spec=io.IOBase)
+            file_handle = mock_open.return_value.__enter__.return_value
+            self.bootloader._setup_efi_image(uuid=None, mbrid=None)
+
+            assert file_handle.write.call_args_list == [
+                call('set btrfs_relative_path="yes"\n'),
+                call('search --file --set=root /boot/mbrid\n'),
+                call('set prefix=($root)/boot/grub2\n'),
+                call('source ($root)/boot/grub2/grub.cfg\n'),
+            ]
+
     @patch.object(BootLoaderConfigGrub2, '_supports_bios_modules')
     @patch('kiwi.bootloader.config.grub2.Command.run')
     @patch('os.path.exists')