add cgpt framework and attribute support.

src/platform/vboot_reference/cgptlib/cgptlib.h

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef VBOOT_REFERENCE_CGPTLIB_H_
 #define VBOOT_REFERENCE_CGPTLIB_H_
 
 #include "gpt.h"
 #include <stdint.h>
 
 enum {
   GPT_SUCCESS = 0,
   GPT_ERROR_NO_VALID_KERNEL,
   GPT_ERROR_INVALID_HEADERS,
   GPT_ERROR_INVALID_ENTRIES,
   GPT_ERROR_INVALID_SECTOR_SIZE,
   GPT_ERROR_INVALID_SECTOR_NUMBER,
   GPT_ERROR_INVALID_UPDATE_TYPE,
 };
 
+const char *GptError(int errno);
+
 /* Bit masks for GptData.modified field. */
 #define GPT_MODIFIED_HEADER1 0x01
 #define GPT_MODIFIED_HEADER2 0x02
 #define GPT_MODIFIED_ENTRIES1 0x04
 #define GPT_MODIFIED_ENTRIES2 0x08
 
 /* The 'update_type' of GptUpdateKernelEntry()
  * We expose TRY and BAD only because those are what verified boot needs.
  * For more precise control on GPT attribute bits, please refer to
  * gpt_internal.h */
@@ skipping 95 matching lines @@
  * of update (GPT_UPDATE_ENTRY_*).
  *
  * On return the modified field may be set, if the GPT data has been modified
  * and should be written to disk.
  *
  * Returns GPT_SUCCESS if successful, else
  *   GPT_ERROR_INVALID_UPDATE_TYPE, invalid 'update_type' is given.
  */
 
 #endif  /* VBOOT_REFERENCE_CGPTLIB_H_ */