efi_loader: disk: add efi_disk_is_system_part()

This function will check if a given handle to device is an EFI system
partition. It will be utilised in implementing capsule-on-disk feature.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Add function description. Return bool.
Reviewed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

2 files changed, 31 insertions, 0 deletions

diff --git a/include/efi_loader.h b/include/efi_loader.h
index f92bfe57e6..0e924ad109 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -394,6 +394,8 @@ efi_status_t efi_disk_register(void);
 int efi_disk_create_partitions(efi_handle_t parent, struct blk_desc *desc,
 			       const char *if_typename, int diskid,
 			       const char *pdevname);
+/* Check if it is EFI system partition */
+bool efi_disk_is_system_part(efi_handle_t handle);
 /* Called by bootefi to make GOP (graphical) interface available */
 efi_status_t efi_gop_register(void);
 /* Called by bootefi to make the network interface available */
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index fd3df80b0b..0582e02158 100644
--- a/lib/efi_loader/efi_disk.c
+++ b/lib/efi_loader/efi_disk.c
@@ -588,3 +588,32 @@ efi_status_t efi_disk_register(void)
 
 	return EFI_SUCCESS;
 }
+
+/**
+ * efi_disk_is_system_part() - check if handle refers to an EFI system partition
+ *
+ * @handle:	handle of partition
+ *
+ * Return:	true if handle refers to an EFI system partition
+ */
+bool efi_disk_is_system_part(efi_handle_t handle)
+{
+	struct efi_handler *handler;
+	struct efi_disk_obj *diskobj;
+	disk_partition_t info;
+	efi_status_t ret;
+	int r;
+
+	/* check if this is a block device */
+	ret = efi_search_protocol(handle, &efi_block_io_guid, &handler);
+	if (ret != EFI_SUCCESS)
+		return false;
+
+	diskobj = container_of(handle, struct efi_disk_obj, header);
+
+	r = part_get_info(diskobj->desc, diskobj->part, &info);
+	if (r)
+		return false;
+
+	return !!(info.bootable & PART_EFI_SYSTEM_PARTITION);
+}