/*! @file       preboot.h
    Copyright 2007 VMware Inc.
    Author: David Elliott
 */
#ifndef _PREBOOT_H__
#define _PREBOOT_H__

#define PREBOOT_SIGNATURE "PREBOOT"

/*! @struct     preboot_header
    If prebooter is used, this will be found in memory by the second-stage booter.
 */
struct preboot_header
{
    uint8_t signature[8];       // "PREBOOT" (with \0 term)
    uint16_t length;            // Size of complete structure
    uint8_t checksum;           // checksum8
    uint8_t pad1;               // Padding - ZERO
    uint32_t p_initrd;          // pointer to initrd in memory
    uint32_t initrd_sectors;    // Number of 512 byte sectors
} __attribute__((packed));

/*! @function   scanPrebootVolumes
    Searches for the preboot header to find the ramdisk.  If found it
    hooks the disk.c code to make the ramdisk device available and
    returns a bvchain representing all volumes on the disk.
 */
extern BVRef scanPrebootVolumes();

/*! @function   selectPrebootVolume
    Given a ramdiskChain (which must currently be a chain of ramdisk volumes
    this function searches for one with the extra extensions directory and
    initializes the gPrebootExtraDir with that path so that the preboot code
    in driver.c knows to search it for additional extensions
 */
extern BVRef selectPrebootVolume(BVRef ramdiskChain);

// String pointer to be filled in if ramdisk contains preboot kexts
extern char *gPrebootExtraDir;

#endif //ndef _PREBOOT_H__