/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2002,2005,2006,2007,2011  Free Software Foundation, Inc.
 *
 *  GRUB 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/symbol.h>
#include <grub/types.h>
#include <grub/partition.h>
#include <grub/disk.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/err.h>

GRUB_MOD_LICENSE("GPLv3+");

#define DVH_MAGIC 0x0be5a941

GRUB_PACKED_START
struct grub_dvh_partition_descriptor
{
	grub_uint32_t length;
	grub_uint32_t start;
	grub_uint32_t type;
};
GRUB_PACKED_END

GRUB_PACKED_START
struct grub_dvh_block
{
	grub_uint32_t magic;
	grub_uint8_t unused[308];
	struct grub_dvh_partition_descriptor parts[16];
	grub_uint32_t checksum;
	grub_uint32_t unused2;
};
GRUB_PACKED_END

static struct grub_partition_map grub_dvh_partition_map;

/* Verify checksum (true=ok).  */
static int
grub_dvh_is_valid(grub_uint32_t* label)
{
	grub_uint32_t* pos;
	grub_uint32_t sum = 0;

	for (pos = label;
		pos < (label + sizeof(struct grub_dvh_block) / 4);
		pos++)
		sum += grub_be_to_cpu32(*pos);

	return !sum;
}

static grub_err_t
dvh_partition_map_iterate(grub_disk_t disk,
	grub_partition_iterate_hook_t hook, void* hook_data)
{
	struct grub_partition p;
	union
	{
		struct grub_dvh_block dvh;
		grub_uint32_t raw[0];
	} block;
	unsigned partnum;
	grub_err_t err;

	p.partmap = &grub_dvh_partition_map;
	err = grub_disk_read(disk, 0, 0, sizeof(struct grub_dvh_block),
		&block);
	if (err)
		return err;

	if (DVH_MAGIC != grub_be_to_cpu32(block.dvh.magic))
		return grub_error(GRUB_ERR_BAD_PART_TABLE, "not a dvh partition table");

	if (!grub_dvh_is_valid(block.raw))
		return grub_error(GRUB_ERR_BAD_PART_TABLE, "invalid checksum");

	/* Maybe another error value would be better, because partition
		 table _is_ recognized but invalid.  */
	for (partnum = 0; partnum < ARRAY_SIZE(block.dvh.parts); partnum++)
	{
		if (block.dvh.parts[partnum].length == 0)
			continue;

		if (partnum == 10)
			continue;

		p.start = grub_be_to_cpu32(block.dvh.parts[partnum].start);
		p.len = grub_be_to_cpu32(block.dvh.parts[partnum].length);
		p.number = p.index = partnum;
		if (hook(disk, &p, hook_data))
			break;
	}

	return grub_errno;
}

/* Partition map type.  */
static struct grub_partition_map grub_dvh_partition_map =
{
	.name = "dvh",
	.iterate = dvh_partition_map_iterate,
};

GRUB_MOD_INIT(part_dvh)
{
	grub_partition_map_register(&grub_dvh_partition_map);
}

GRUB_MOD_FINI(part_dvh)
{
	grub_partition_map_unregister(&grub_dvh_partition_map);
}
