[parted-devel] [PATCH 1/4] libparted: Fix handling of gpt partition types

[Brian C. Lane]

This restores the previous behavior by testing the GUID against the list
of known types and skipping the filesystem GUID reset. Now the sequence
of:

ped_partition_new(...)
ped_partition_set_flag(part, PED_PARTITION_BIOS_GRUB, 1);
ped_partition_set_system(part, ped_file_system_type_get("ext4"));

Will keep the GUID set to PED_PARTITION_BIOS_GRUB, which is how it used
to behave.
---
 libparted/labels/gpt.c | 45 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/libparted/labels/gpt.c b/libparted/labels/gpt.c
index 0e9e060..4aae89e 100644
--- a/libparted/labels/gpt.c
+++ b/libparted/labels/gpt.c
@@ -196,6 +196,24 @@ static const struct flag_uuid_mapping_t flag_uuid_mapping[] =
     { PED_PARTITION_SWAP,               PARTITION_SWAP_GUID },
 };
 
+static const efi_guid_t skip_set_system_guids[] =
+{
+    PARTITION_LVM_GUID,
+    PARTITION_SWAP_GUID,
+    PARTITION_RAID_GUID,
+    PARTITION_PREP_GUID,
+    PARTITION_SYSTEM_GUID,
+    PARTITION_BIOS_GRUB_GUID,
+    PARTITION_HPSERVICE_GUID,
+    PARTITION_MSFT_RESERVED_GUID,
+    PARTITION_BASIC_DATA_GUID,
+    PARTITION_MSFT_RECOVERY,
+    PARTITION_APPLE_TV_RECOVERY_GUID,
+    PARTITION_IRST_GUID,
+    PARTITION_CHROMEOS_KERNEL_GUID,
+    PARTITION_BLS_BOOT_GUID,
+};
+
 static const struct flag_uuid_mapping_t* _GL_ATTRIBUTE_CONST
 gpt_find_flag_uuid_mapping (PedPartitionFlag flag)
 {
@@ -1421,6 +1439,21 @@ gpt_partition_destroy (PedPartition *part)
   _ped_partition_free (part);
 }
 
+/* is_skip_guid checks the guid against the list of guids that should not be
+ * overridden by set_system. It returns a 1 if it is in the list.
+*/
+static bool
+is_skip_guid(efi_guid_t guid) {
+    int n = sizeof(skip_set_system_guids) / sizeof(skip_set_system_guids[0]);
+    for (int i = 0; i < n; ++i) {
+        if (guid_cmp(guid, skip_set_system_guids[i]) == 0) {
+            return 1;
+        }
+    }
+
+    return 0;
+}
+
 static int
 gpt_partition_set_system (PedPartition *part,
                           const PedFileSystemType *fs_type)
@@ -1431,6 +1464,11 @@ gpt_partition_set_system (PedPartition *part,
 
   part->fs_type = fs_type;
 
+  // Is this a GUID that should skip fs_type checking?
+  if (is_skip_guid(gpt_part_data->type)) {
+      return 1;
+  }
+
   if (fs_type)
     {
       if (strncmp (fs_type->name, "fat", 3) == 0
@@ -1563,10 +1601,13 @@ gpt_partition_set_flag (PedPartition *part, PedPartitionFlag flag, int state)
   const struct flag_uuid_mapping_t* p = gpt_find_flag_uuid_mapping (flag);
   if (p)
   {
-    if (state)
+    if (state) {
       gpt_part_data->type = p->type_uuid;
-    else if (guid_cmp (gpt_part_data->type, p->type_uuid) == 0)
+    } else if (guid_cmp (gpt_part_data->type, p->type_uuid) == 0) {
+      // Clear the GUID so that fs_type will be used to return it to the default
+      gpt_part_data->type = PARTITION_LINUX_DATA_GUID;
       return gpt_partition_set_system (part, part->fs_type);
+    }
     return 1;
   }
 
-- 
2.37.1