fix(arm,bootloader,efi): patch grub.cfg used for upgrading

Use the grub.cfg bundled within leapp if we detect that
system's grub.cfg contains problematic configuration which
will not load grubenv of the upgrade BLS entry. We need
to ensure that this grubenv is loaded, as without it we
cannot guarantee a successful boot into upgrade environment.

repos/system_upgrade/el8toel9/actors/addarmbootloaderworkaround/files/grub2_config_template

@@ -0,0 +1,26 @@
+set timeout=0
+
+# Make sure to load EFI/leapp/grubenv and not system's default path
+if [ -f ${config_directory}/grubenv ]; then
+  load_env -f ${config_directory}/grubenv
+elif [ -s $prefix/grubenv ]; then
+  load_env
+fi
+
+# EFI/leapp/grubenv contains our upgrade BLS entry as saved_entry
+if [ "${next_entry}" ] ; then
+   set default="${next_entry}"
+   set next_entry=
+   save_env next_entry
+   set boot_once=true
+else
+   set default="${saved_entry}"
+fi
+
+search --no-floppy --set=root --fs-uuid LEAPP_BOOT_UUID
+set boot=${root}
+function load_video {
+  insmod all_video
+}
+${serial}${terminal_input}${terminal_output}
+blscfg

repos/system_upgrade/el8toel9/actors/addarmbootloaderworkaround/libraries/addupgradebootloader.py

@@ -6,6 +6,7 @@
 from leapp.libraries.common.grub import (
     canonical_path_to_efi_format,
     EFIBootInfo,
+    get_boot_partition,
     get_device_number,
     get_efi_device,
     get_efi_partition,
@@ -26,6 +27,15 @@
 
 CONTAINER_DOWNLOAD_DIR = '/tmp_pkg_download_dir'
 
+LEAPP_GRUB2_CFG_TEMPLATE = 'grub2_config_template'
+"""
+Our grub configuration file template that is used in case the system's grubcfg would not load our grubenv.
+
+The template contains placeholders named with LEAPP_*, that need to be replaced in order to
+obtain a valid config.
+
+"""
+
 
 def _copy_file(src_path, dst_path):
     if os.path.exists(dst_path):
@@ -49,11 +59,14 @@ def process():
         context.copytree_from(RHEL_EFIDIR_CANONICAL_PATH, LEAPP_EFIDIR_CANONICAL_PATH)
 
         _copy_grub_files(['grubenv', 'grub.cfg'], ['user.cfg'])
-        _link_grubenv_to_upgrade_entry()
 
         efibootinfo = EFIBootInfo()
         current_boot_entry = efibootinfo.entries[efibootinfo.current_bootnum]
         upgrade_boot_entry = _add_upgrade_boot_entry(efibootinfo)
+
+        leapp_efi_grubenv = os.path.join(EFI_MOUNTPOINT, LEAPP_EFIDIR_CANONICAL_PATH, 'grubenv')
+        patch_efi_redhat_grubcfg_to_load_correct_grubenv()
+
         _set_bootnext(upgrade_boot_entry.boot_number)
 
         efibootentry_fields = ['boot_number', 'label', 'active', 'efi_bin_source']
@@ -183,3 +196,90 @@ def _set_bootnext(boot_number):
         run(['/usr/sbin/efibootmgr', '--bootnext', boot_number])
     except CalledProcessError:
         raise StopActorExecutionError('Could not set boot entry {} as BootNext.'.format(boot_number))
+
+
+def _notify_user_to_check_grub2_cfg():
+    # Or maybe rather ask a question in a dialog? But this is rare, so maybe continuing is fine.
+    pass
+
+
+def _will_grubcfg_read_our_grubenv(grubcfg_path):
+    with open(grubcfg_path) as grubcfg:
+        config_lines = grubcfg.readlines()
+
+    will_read = False
+    for line in config_lines:
+        if line.strip() == 'load_env -f ${config_directory}/grubenv':
+            will_read = True
+            break
+
+    return will_read
+
+
+def _get_boot_device_uuid():
+    boot_device = get_boot_partition()
+    try:
+        raw_device_info_lines = run(['blkid', boot_device], split=True)['stdout']
+        raw_device_info = raw_device_info_lines[0]  # There is only 1 output line
+
+        uuid_needle_start_pos = raw_device_info.index('UUID')
+        raw_device_info = raw_device_info[uuid_needle_start_pos:]  # results in: "UUID="..." ....
+
+        uuid = raw_device_info.split(' ', 1)[0]  # UUID cannot contain spaces
+        uuid = uuid[len('UUID='):]  # Remove UUID=
+        uuid = uuid.strip('"')
+        return uuid
+
+    except CalledProcessError as error:
+        details = {'details': 'blkid failed with error: {}'.format(error)}
+        raise StopActorExecutionError('Failed to obtain UUID of /boot partition', details=details)
+
+
+def _prepare_config_contents():
+    config_template_path = api.get_actor_file_path(LEAPP_GRUB2_CFG_TEMPLATE)
+    with open(config_template_path) as config_template_handle:
+        config_template = config_template_handle.read()
+
+    substitutions = {
+        'LEAPP_BOOT_UUID': _get_boot_device_uuid()
+    }
+
+    api.current_logger().debug(
+        'Applying the following substitution map to grub config template: {}'.format(substitutions)
+    )
+
+    for placeholder, placeholder_value in substitutions.items():
+        config_template = config_template.replace(placeholder, placeholder_value)
+
+    return config_template
+
+
+def _write_config(config_path, config_contents):
+    with open(config_path, 'w') as grub_cfg_handle:
+        grub_cfg_handle.write(config_contents)
+
+
+def patch_efi_redhat_grubcfg_to_load_correct_grubenv():
+    """
+    Replaces /boot/efi/EFI/redhat/grub2.cfg with a patched grub2.cfg shipped in leapp.
+
+    The grub2.cfg shipped on some AWS images omits the section that loads grubenv different
+    EFI entries. Thus, we need to replace it with our own that will load grubenv shipped
+    of our UEFI boot entry.
+    """
+    leapp_grub_cfg_path = os.path.join(EFI_MOUNTPOINT, LEAPP_EFIDIR_CANONICAL_PATH, 'grub.cfg')
+
+    if not os.path.isfile(leapp_grub_cfg_path):
+        msg = 'The file {} does not exists, cannot check whether bootloader is configured properly.'
+        raise StopActorExecutionError(msg.format(leapp_grub_cfg_path))
+
+    if _will_grubcfg_read_our_grubenv(leapp_grub_cfg_path):
+        api.current_logger().debug('The current grub.cfg will read our grubenv without any modifications.')
+        return
+
+    api.current_logger().info('Current grub2.cfg is likely faulty (would not read our grubenv), patching.')
+
+    config_contents = _prepare_config_contents()
+    _write_config(leapp_grub_cfg_path, config_contents)
+
+    api.current_logger().info('New upgrade grub.cfg has been written to {}'.format(leapp_grub_cfg_path))

repos/system_upgrade/el8toel9/actors/addarmbootloaderworkaround/tests/test_addarmbootloaderworkaround.py

@@ -298,6 +298,9 @@ def mock_add_upgrade_boot_entry(efibootinfo):
     monkeypatch.setattr(addupgradebootloader, '_add_upgrade_boot_entry', mock_add_upgrade_boot_entry)
     monkeypatch.setattr(addupgradebootloader, '_set_bootnext', lambda _: None)
 
+    monkeypatch.setattr(addupgradebootloader, 'patch_efi_redhat_grubcfg_to_load_correct_grubenv',
+                        lambda: None)
+
     addupgradebootloader.process()
 
     assert api.produce.called == 1
@@ -307,6 +310,32 @@ def mock_add_upgrade_boot_entry(efibootinfo):
     expected = ArmWorkaroundEFIBootloaderInfo(
             original_entry=EFIBootEntry(**{f: getattr(TEST_RHEL_EFI_ENTRY, f) for f in efibootentry_fields}),
             upgrade_entry=EFIBootEntry(**{f: getattr(TEST_UPGRADE_EFI_ENTRY, f) for f in efibootentry_fields}),
+            upgrade_bls_dir='/boot/upgrade-loader/entries',
+            upgrade_entry_efi_path='/boot/efi/EFI/leapp/',
         )
     actual = api.produce.model_instances[0]
     assert actual == expected
+
+
+@pytest.mark.parametrize('is_config_ok', (True, False))
+def test_patch_grubcfg(is_config_ok, monkeypatch):
+
+    expected_grubcfg_path = os.path.join(addupgradebootloader.EFI_MOUNTPOINT,
+                                         addupgradebootloader.LEAPP_EFIDIR_CANONICAL_PATH,
+                                         'grub.cfg')
+    def isfile_mocked(path):
+        assert expected_grubcfg_path == path
+        return True
+
+    def prepare_config_contents_mocked():
+        return 'config contents'
+
+    def write_config(path, contents):
+        assert not is_config_ok  # We should write only when the config is not OK
+        assert path == expected_grubcfg_path
+        assert contents == 'config contents'
+
+    monkeypatch.setattr(os.path, 'isfile', isfile_mocked)
+    monkeypatch.setattr(addupgradebootloader, '_will_grubcfg_read_our_grubenv', lambda cfg_path: is_config_ok)
+    monkeypatch.setattr(addupgradebootloader, '_prepare_config_contents', prepare_config_contents_mocked)
+    monkeypatch.setattr(addupgradebootloader, '_write_config', write_config)

repos/system_upgrade/el8toel9/actors/removeupgradeefientry/libraries/removeupgradeefientry.py

@@ -35,8 +35,8 @@ def remove_upgrade_efi_entry():
 
     bootloader_info = get_workaround_efi_info()
 
-    _copy_grub_files(['grubenv', 'grub.cfg'], ['user.cfg'])
-    _link_grubenv_to_rhel_entry()
+    # _copy_grub_files(['grubenv', 'grub.cfg'], ['user.cfg'])
+    # _link_grubenv_to_rhel_entry()
 
     upgrade_boot_number = bootloader_info.upgrade_entry.boot_number
     try: