[efi] Split device path functions out to efi_path.c

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/src/interface/efi/efi_path.c b/src/interface/efi/efi_path.c
new file mode 100644
index 000000000..1b297567c
--- /dev/null
+++ b/src/interface/efi/efi_path.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2020 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_path.h>
+
+/** @file
+ *
+ * EFI device paths
+ *
+ */
+
+/**
+ * Find end of device path
+ *
+ * @v path		Path to device
+ * @ret path_end	End of device path
+ */
+EFI_DEVICE_PATH_PROTOCOL * efi_path_end ( EFI_DEVICE_PATH_PROTOCOL *path ) {
+
+	while ( path->Type != END_DEVICE_PATH_TYPE ) {
+		path = ( ( ( void * ) path ) +
+			 /* There's this amazing new-fangled thing known as
+			  * a UINT16, but who wants to use one of those? */
+			 ( ( path->Length[1] << 8 ) | path->Length[0] ) );
+	}
+
+	return path;
+}
+
+/**
+ * Find length of device path (excluding terminator)
+ *
+ * @v path		Path to device
+ * @ret path_len	Length of device path
+ */
+size_t efi_path_len ( EFI_DEVICE_PATH_PROTOCOL *path ) {
+	EFI_DEVICE_PATH_PROTOCOL *end = efi_path_end ( path );
+
+	return ( ( ( void * ) end ) - ( ( void * ) path ) );
+}