[U-Boot] [PATCH 1/1] efi_loader: volume name in EFI_FILE_PROTOCOL.GetInfo()

[Heinrich Schuchardt]

We cannot determine the volume name in U-Boot. Instead of providing a dummy
volume name in case of EFI_FILE_SYSTEM_INFO and EFI_UNSUPPORTED in case of
EFI_FILE_SYSTEM_VOLUME_LABEL consistently return an empty string.

Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
 include/efi_api.h         |  4 ++++
 lib/efi_loader/efi_file.c | 18 ++++++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/include/efi_api.h b/include/efi_api.h
index cb895f31e5..b665036c8d 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -1505,6 +1505,10 @@ struct efi_simple_file_system_protocol {
 	EFI_GUID(0x09576e93, 0x6d3f, 0x11d2, \
 		 0x8e, 0x39, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)

+#define EFI_FILE_SYSTEM_VOLUME_LABEL_ID \
+	EFI_GUID(0xdb47d7d3, 0xfe81, 0x11d3, \
+		 0x9a, 0x35, 0x00, 0x90, 0x27, 0x3f, 0xC1, 0x4d)
+
 #define EFI_FILE_MODE_READ	0x0000000000000001
 #define EFI_FILE_MODE_WRITE	0x0000000000000002
 #define EFI_FILE_MODE_CREATE	0x8000000000000000
diff --git a/lib/efi_loader/efi_file.c b/lib/efi_loader/efi_file.c
index 504b1d1755..2f03ae71fc 100644
--- a/lib/efi_loader/efi_file.c
+++ b/lib/efi_loader/efi_file.c
@@ -15,6 +15,9 @@
 /* GUID for file system information */
 const efi_guid_t efi_file_system_info_guid = EFI_FILE_SYSTEM_INFO_GUID;

+/* GUID to obtain the volume label */
+const efi_guid_t efi_system_volume_label_id = EFI_FILE_SYSTEM_VOLUME_LABEL_ID;
+
 struct file_system {
 	struct efi_simple_file_system_protocol base;
 	struct efi_device_path *dp;
@@ -637,9 +640,7 @@ static efi_status_t EFIAPI efi_file_getinfo(struct efi_file_handle *file,
 			ret = EFI_DEVICE_ERROR;
 			goto error;
 		}
-		required_size = sizeof(*info) + 2 *
-				(utf8_utf16_strlen((const char *)part.name) +
-				 1);
+		required_size = sizeof(*info) + 2;
 		if (*buffer_size < required_size) {
 			*buffer_size = required_size;
 			ret = EFI_BUFFER_TOO_SMALL;
@@ -655,10 +656,15 @@ static efi_status_t EFIAPI efi_file_getinfo(struct efi_file_handle *file,
 		info->block_size = part.blksz;
 		/*
 		 * TODO: The volume label is not available in U-Boot.
-		 * Use the partition name as substitute.
 		 */
-		dst = info->volume_label;
-		utf8_utf16_strcpy(&dst, (const char *)part.name);
+		info->volume_label[0] = 0;
+	} else if (!guidcmp(info_type, &efi_system_volume_label_id)) {
+		if (*buffer_size < 2) {
+			*buffer_size = 2;
+			ret = EFI_BUFFER_TOO_SMALL;
+			goto error;
+		}
+		*(u16 *)buffer = 0;
 	} else {
 		ret = EFI_UNSUPPORTED;
 	}
--
2.23.0