Expose GptData.current_kernel as an output of GptNextKernelEntry()

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>
@@ skipping 68 matching lines @@
                                   *   header (size: 16 KB) */
   uint32_t sector_bytes;         /* Size of a LBA sector, in bytes */
   uint64_t drive_sectors;        /* Size of drive in LBA sectors, in sectors */
 
   /* Outputs */
   uint8_t modified;              /* Which inputs have been modified?
                                   * 0x01 = header1
                                   * 0x02 = header2
                                   * 0x04 = table1
                                   * 0x08 = table2  */
-
-  /* Internal state */
   int current_kernel; /* the current chromeos kernel index in partition table.
                        * -1 means not found on drive. */
 } GptData;
 
 int GptInit(GptData *gpt);
 /* Initializes the GPT data structure's internal state.  The following fields
  * must be filled before calling this function:
  *
  *   primary_header
  *   secondary_header
@@ skipping 11 matching lines @@
  *   GPT_ERROR_INVALID_ENTRIES, both partition table entries are invalid, enters
  *                              recovery mode,
  *   GPT_ERROR_INVALID_SECTOR_SIZE, size of a sector is not supported,
  *   GPT_ERROR_INVALID_SECTOR_NUMBER, number of sectors in drive is invalid (too
  *                                    small) */
 
 int GptNextKernelEntry(GptData *gpt, uint64_t *start_sector, uint64_t *size);
 /* Provides the location of the next kernel partition, in order of decreasing
  * priority.  On return the start_sector parameter contains the LBA sector
  * for the start of the kernel partition, and the size parameter contains the
- * size of the kernel partition in LBA sectors.
+ * size of the kernel partition in LBA sectors.  gpt.current_kernel contains
+ * the partition index of the current chromeos kernel partition.
  *
  * Returns GPT_SUCCESS if successful, else
  *   GPT_ERROR_NO_VALID_KERNEL, no avaliable kernel, enters recovery mode */
 
 int GptUpdateKernelEntry(GptData *gpt, uint32_t update_type);
 /* Updates the kernel entry with the specified index, using the specified type
  * 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_ */