utils: add enforce_gpt argument to get_efi_partition()

The Windows bootloader only supports a UEFI boot from a GPT
partition. Set enforce_gpt to True in every codepath related to
Windows. When enforce_gpt is set to True get_efi_partition()
raises an exception when an MBR partition scheme is detected.

1 files changed, 6 insertions, 3 deletions

diff --git a/src/utils/disk.py b/src/utils/disk.py
index b4541cc..99cf36f 100644
--- a/src/utils/disk.py
+++ b/src/utils/disk.py
@@ -41,9 +41,12 @@ def get_partition_device(disknum, partnum):
     raise ValueError(f'No such partition with disk index {disknum} and partition index {partnum}')
 
 
-def get_efi_partition(disknum):
+def get_efi_partition(disknum, enforce_gpt):
     """
-    Look for an EFI System Partition at the n-th disk. If disknum is invalid an exception is thrown
+    Look for an EFI System Partition at the n-th disk. If disknum is invalid an
+    exception is thrown.
+    If enforce_gpt is set to True the ESP will be ignored in a MBR partition
+    scheme.
 
     Returns tuple with:
         - Device name containing the ESP
@@ -57,7 +60,7 @@ def get_efi_partition(disknum):
     disk = get_disks()[disk_index]
     cxt = fdisk.Context(f'/dev/{disk}')
 
-    if cxt.label == fdisk.FDISK_DISKLABEL_DOS:
+    if enforce_gpt and cxt.label == fdisk.FDISK_DISKLABEL_DOS:
         raise RuntimeError(f'Disk has DOS partition scheme, cannot find ESP at /dev/{disk}')
 
     for pa in cxt.partitions: