/* sun.c - Read SUN style partition tables.  */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2002,2005,2006,2007  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 GRUB_PARTMAP_SUN_MAGIC 0xDABE
#define GRUB_PARTMAP_SUN_MAX_PARTS 8
#define GRUB_PARTMAP_SUN_WHOLE_DISK_ID 0x05

GRUB_PACKED_START
struct grub_sun_partition_info
{
	grub_uint8_t spare1;
	grub_uint8_t id;
	grub_uint8_t spare2;
	grub_uint8_t flags;
};
GRUB_PACKED_END

GRUB_PACKED_START
struct grub_sun_partition_descriptor
{
	grub_uint32_t start_cylinder;
	grub_uint32_t num_sectors;
};
GRUB_PACKED_END

GRUB_PACKED_START
struct grub_sun_block
{
	grub_uint8_t  info[128];      /* Informative text string.  */
	grub_uint8_t  spare0[14];
	struct grub_sun_partition_info infos[8];
	grub_uint8_t  spare1[246];    /* Boot information etc.  */
	grub_uint16_t  rspeed;        /* Disk rotational speed.  */
	grub_uint16_t  pcylcount;     /* Physical cylinder count.  */
	grub_uint16_t  sparecyl;      /* extra sects per cylinder.  */
	grub_uint8_t  spare2[4];      /* More magic...  */
	grub_uint16_t  ilfact;        /* Interleave factor.  */
	grub_uint16_t  ncyl;          /* Data cylinder count.  */
	grub_uint16_t  nacyl;         /* Alt. cylinder count.  */
	grub_uint16_t  ntrks;         /* Tracks per cylinder.  */
	grub_uint16_t  nsect;         /* Sectors per track.  */
	grub_uint8_t  spare3[4];      /* Even more magic...  */
	struct grub_sun_partition_descriptor partitions[8];
	grub_uint16_t  magic;         /* Magic number.  */
	grub_uint16_t  csum;          /* Label xor'd checksum.  */
};
GRUB_PACKED_END

static struct grub_partition_map grub_sun_partition_map;

/* Verify checksum (true=ok).  */
static int
grub_sun_is_valid(grub_uint16_t* label)
{
	grub_uint16_t* pos;
	grub_uint16_t sum = 0;

	for (pos = label;
		pos < (label + sizeof(struct grub_sun_block) / 2);
		pos++)
		sum ^= *pos;

	return !sum;
}

static grub_err_t
sun_partition_map_iterate(grub_disk_t disk,
	grub_partition_iterate_hook_t hook, void* hook_data)
{
	struct grub_partition p;
	union
	{
		struct grub_sun_block sun_block;
		grub_uint16_t raw[0];
	} block;
	int partnum;
	grub_err_t err;

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

	if (GRUB_PARTMAP_SUN_MAGIC != grub_be_to_cpu16(block.sun_block.magic))
		return grub_error(GRUB_ERR_BAD_PART_TABLE, "not a sun partition table");

	if (!grub_sun_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 < GRUB_PARTMAP_SUN_MAX_PARTS; partnum++)
	{
		struct grub_sun_partition_descriptor* desc;

		if (block.sun_block.infos[partnum].id == 0
			|| block.sun_block.infos[partnum].id == GRUB_PARTMAP_SUN_WHOLE_DISK_ID)
			continue;

		desc = &block.sun_block.partitions[partnum];
		p.start = ((grub_uint64_t)grub_be_to_cpu32(desc->start_cylinder)
			* grub_be_to_cpu16(block.sun_block.ntrks)
			* grub_be_to_cpu16(block.sun_block.nsect));
		p.len = grub_be_to_cpu32(desc->num_sectors);
		p.number = p.index = partnum;
		if (p.len)
		{
			if (hook(disk, &p, hook_data))
				partnum = GRUB_PARTMAP_SUN_MAX_PARTS;
		}
	}

	return grub_errno;
}

/* Partition map type.  */
static struct grub_partition_map grub_sun_partition_map =
{
	.name = "sun",
	.iterate = sun_partition_map_iterate,
};

GRUB_MOD_INIT(part_sun)
{
	grub_partition_map_register(&grub_sun_partition_map);
}

GRUB_MOD_FINI(part_sun)
{
	grub_partition_map_unregister(&grub_sun_partition_map);
}

