fix(arm,bootloaders): use correct blsdir when boot is not separate

Currently, leapp does not distinguish between having and not having a
separate /boot partition. Since blsdir is relative to the device
on which /boot resides, ARM systems without a separate /boot could
not boot into our upgrade environment, and, instead, they booted
back into pre-upgrade RHEL8. This patch adds additional handling
for non-separate /boot to the process of specifying custom blsdir.

Resolves: RHEL-41193

Author: Michal Hecko

repos/system_upgrade/common/actors/addupgradebootentry/libraries/addupgradebootentry.py

@@ -399,10 +399,18 @@ def modify_our_grubenv_to_have_separate_blsdir(efi_info):
     )
 
     grubenv_vars = _list_grubenv_variables()
-    system_bls_dir = grubenv_vars.get('blsdir', '/loader/entries').lstrip('/')
+
+    if os.path.ismount('/boot'):
+        default_blsdir = '/loader/entries'
+        grub_root_device_mountpoint = '/boot'
+    else:
+        default_blsdir = '/boot/loader/entries'
+        grub_root_device_mountpoint = '/'
+
+    system_bls_dir = grubenv_vars.get('blsdir', default_blsdir).lstrip('/')
 
     # BLS dir is relative to /boot, prepend it so we can list its contents
-    system_bls_dir = os.path.join('/boot', system_bls_dir)
+    system_bls_dir = os.path.join(grub_root_device_mountpoint, system_bls_dir)
 
     # Find our loader entry
     try:
@@ -444,7 +452,12 @@ def modify_our_grubenv_to_have_separate_blsdir(efi_info):
 
     shutil.move(leapp_bls_entry_fullpath, bls_entry_dst)
 
-    upgrade_bls_dir_rel_to_boot = efi_info.upgrade_bls_dir[len('/boot'):]
+    # BLSDIR must be relative to grub's root device. Therefore, if /boot is a separate mountpoint
+    # we need to convert blsdir=/boot/upgrade-loader into blsdir=/upgrade-loader. If there is no
+    # separate root, then root=/, so rstripping('/') produces an empty string.
+    # In such a case, the relative paths stays unchanged: blsdir=/boot/upgrade-loader
+    grub_root_device_mp_without_trail = grub_root_device_mountpoint.rstrip('/')
+    upgrade_bls_dir_rel_to_boot = efi_info.upgrade_bls_dir[len(grub_root_device_mp_without_trail):]
 
     # Modify leapp's grubenv to define our own BLSDIR
     try:

repos/system_upgrade/common/actors/addupgradebootentry/tests/unit_test_addupgradebootentry.py

@@ -331,7 +331,8 @@ def readlink_mock(path):
     assert uuid == 'MY_UUID1'
 
 
-def test_modify_grubenv_to_have_separate_blsdir(monkeypatch):
+@pytest.mark.parametrize('has_separate_boot', (True, False))
+def test_modify_grubenv_to_have_separate_blsdir(monkeypatch, has_separate_boot):
     efi_info = ArmWorkaroundEFIBootloaderInfo(
         original_entry=EFIBootEntry(
             boot_number='0001',
@@ -349,9 +350,14 @@ def test_modify_grubenv_to_have_separate_blsdir(monkeypatch):
         upgrade_entry_efi_path='/boot/efi/EFI/leapp'
     )
 
+    def is_mount_mocked(path):
+        assert path.rstrip('/') == '/boot'
+        return has_separate_boot
+
     def list_grubenv_variables_mock():
+        blsdir = '/blsdir' if has_separate_boot else '/boot/blsdir'
         return {
-            'blsdir': '/blsdir'
+            'blsdir': blsdir
         }
 
     def listdir_mock(dir_path):
@@ -369,11 +375,13 @@ def move_mocked(src, dst):
         assert dst == '/boot/upgrade-loader/entries/4a9c76478b98444fb5e0fbf533950edf-upgrade.aarch64.conf'
 
     def run_mocked(cmd, *arg, **kwargs):
-        assert cmd == ['grub2-editenv', '/boot/efi/EFI/leapp/grubenv', 'set', 'blsdir=/upgrade-loader/entries']
+        blsdir = '/upgrade-loader/entries' if has_separate_boot else '/boot/upgrade-loader/entries'
+        assert cmd == ['grub2-editenv', '/boot/efi/EFI/leapp/grubenv', 'set', 'blsdir={}'.format(blsdir)]
 
     monkeypatch.setattr(addupgradebootentry, '_list_grubenv_variables', list_grubenv_variables_mock)
     monkeypatch.setattr(os, 'listdir', listdir_mock)
     monkeypatch.setattr(os.path, 'exists', assert_path_correct)
+    monkeypatch.setattr(os.path, 'ismount', is_mount_mocked)
     monkeypatch.setattr(os, 'makedirs', assert_path_correct)
     monkeypatch.setattr(shutil, 'move', move_mocked)
     monkeypatch.setattr(addupgradebootentry, 'run', run_mocked)