[PATCH 1/2] efi_loader: multi part device paths to text

[Heinrich Schuchardt]

Our current implementation of
EFI_DEVICE_PATH_TO_TEXT_PROTOCOL.ConvertDevicePathToText() truncates multi
part device paths after the first part. We should convert all parts.

Render device path instance ends as commas. This is not explicitly
described in the UEFI spec but mimics what EDK II does.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 lib/efi_loader/efi_device_path_to_text.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/lib/efi_loader/efi_device_path_to_text.c b/lib/efi_loader/efi_device_path_to_text.c
index 1aaa9f94fa..81b8ac23ba 100644
--- a/lib/efi_loader/efi_device_path_to_text.c
+++ b/lib/efi_loader/efi_device_path_to_text.c
@@ -369,11 +369,18 @@ static uint16_t EFIAPI *efi_convert_device_path_to_text(

 	if (!device_path)
 		goto out;
-	while (device_path &&
-	       str + MAX_NODE_LEN < buffer + MAX_PATH_LEN) {
-		*str++ = '/';
-		str = efi_convert_single_device_node_to_text(str, device_path);
-		device_path = efi_dp_next(device_path);
+	while (device_path && str + MAX_NODE_LEN < buffer + MAX_PATH_LEN) {
+		if (device_path->type == DEVICE_PATH_TYPE_END) {
+			if (device_path->sub_type !=
+			    DEVICE_PATH_SUB_TYPE_INSTANCE_END)
+				break;
+			*str++ = ',';
+		} else {
+			*str++ = '/';
+			str = efi_convert_single_device_node_to_text(
+							str, device_path);
+		}
+		*(u8 **)&device_path += device_path->length;
 	}

 	text = efi_str_to_u16(buffer);
--
2.30.0