/* apple.c - Read macintosh partition tables.  */
/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2002,2004,2005,2006,2007,2008,2009  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 <https://www.gnu.org/licenses/>.
 */

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

#define GRUB_APPLE_HEADER_MAGIC 0x4552
#define GRUB_APPLE_PART_MAGIC 0x504D

struct grub_apple_header {
	/* The magic number to identify the partition map, it should have
	the value `0x4552'.  */
	grub_uint16_t magic;
	grub_uint16_t blocksize;
};

struct grub_apple_part {
	/* The magic number to identify this as a partition, it should have
	the value `0x504D'.  */
	grub_uint16_t magic;

	/* Reserved.  */
	grub_uint16_t reserved;

	/* The size of the partition map in blocks.  */
	grub_uint32_t partmap_size;

	/* The first physical block of the partition.  */
	grub_uint32_t first_phys_block;

	/* The amount of blocks.  */
	grub_uint32_t blockcnt;

	/* The partition name.  */
	char partname[32];

	/* The partition type.  */
	char parttype[32];

	/* The first datablock of the partition.  */
	grub_uint32_t datablocks_first;

	/* The amount datablocks.  */
	grub_uint32_t datablocks_count;

	/* The status of the partition. (???)  */
	grub_uint32_t status;

	/* The first block on which the bootcode can be found.  */
	grub_uint32_t bootcode_pos;

	/* The size of the bootcode in bytes.  */
	grub_uint32_t bootcode_size;

	/* The load address of the bootcode.  */
	grub_uint32_t bootcode_loadaddr;

	/* Reserved.  */
	grub_uint32_t reserved2;

	/* The entry point of the bootcode.  */
	grub_uint32_t bootcode_entrypoint;

	/* Reserved.  */
	grub_uint32_t reserved3;

	/* A checksum of the bootcode.  */
	grub_uint32_t bootcode_checksum;

	/* The processor type.  */
	char processor[16];

	/* Padding.  */
	grub_uint16_t pad[187];
};

struct grub_partition_map grub_apple_partition_map;

static grub_err_t
apple_partition_map_iterate(grub_disk_t disk,
	int (*hook) (grub_disk_t disk,
		const grub_partition_t partition,
		void *closure),
	void *closure) {
	struct grub_partition part;
	struct grub_apple_header aheader;
	struct grub_apple_part apart;
	int partno = 0, partnum = 0;
	unsigned pos;

	part.partmap = &grub_apple_partition_map;

	if (grub_disk_read (disk, 0, 0, sizeof (aheader), &aheader)) {
		return grub_errno;
	}

	if (grub_be_to_cpu16 (aheader.magic) != GRUB_APPLE_HEADER_MAGIC) {
		grub_dprintf ("partition",
			"bad magic (found 0x%x; wanted 0x%x\n",
			grub_be_to_cpu16 (aheader.magic),
			GRUB_APPLE_HEADER_MAGIC);
		goto fail;
	}

	pos = grub_be_to_cpu16 (aheader.blocksize);

	do {
		part.offset = pos / GRUB_DISK_SECTOR_SIZE;
		part.index = pos % GRUB_DISK_SECTOR_SIZE;

		if (grub_disk_read (disk, part.offset, part.index, sizeof (struct grub_apple_part), &apart)) {
			return grub_errno;
		}

		if (grub_be_to_cpu16 (apart.magic) != GRUB_APPLE_PART_MAGIC) {
			grub_dprintf ("partition",
				"partition %d: bad magic (found 0x%x; wanted 0x%x\n",
				partno,
				grub_be_to_cpu16 (apart.magic),
				GRUB_APPLE_PART_MAGIC);
			break;
		}

		if (partnum == 0) {
			partnum = grub_be_to_cpu32 (apart.partmap_size);
		}

		part.start = ((grub_disk_addr_t)grub_be_to_cpu32 (apart.first_phys_block) * grub_be_to_cpu16 (aheader.blocksize)) / GRUB_DISK_SECTOR_SIZE;
		part.len = ((grub_disk_addr_t)grub_be_to_cpu32 (apart.blockcnt) * grub_be_to_cpu16 (aheader.blocksize)) / GRUB_DISK_SECTOR_SIZE;
		part.offset = pos;
		part.index = partno;
		part.number = partno;

		grub_dprintf ("partition",
			"partition %d: name %s, type %s, start 0x%x, len 0x%x\n",
			partno,
			apart.partname,
			apart.parttype,
			grub_be_to_cpu32 (apart.first_phys_block),
			grub_be_to_cpu32 (apart.blockcnt));

		if (hook (disk, &part, closure)) {
			return grub_errno;
		}

		pos += grub_be_to_cpu16 (aheader.blocksize);
		partno++;
	} while (partno < partnum);

	if (partno != 0) {
		return 0;
	}

fail:
	return grub_error (GRUB_ERR_BAD_PART_TABLE,
		"Apple partition map not found");
}

/* Partition map type.  */
struct grub_partition_map grub_apple_partition_map = {
	.name = "apple",
	.iterate = apple_partition_map_iterate,
};