[linux.git] / fs / hfs / part_tbl.c

/*
 *  linux/fs/hfs/part_tbl.c
 *
 * Copyright (C) 1996-1997  Paul H. Hargrove
 * (C) 2003 Ardis Technologies <[email protected]>
 * This file may be distributed under the terms of the GNU General Public License.
 *
 * Original code to handle the new style Mac partition table based on
 * a patch contributed by Holger Schemel ([email protected]).
 */

#include "hfs_fs.h"

/*
 * The new style Mac partition map
 *
 * For each partition on the media there is a physical block (512-byte
 * block) containing one of these structures.  These blocks are
 * contiguous starting at block 1.
 */
struct new_pmap {
	__be16	pmSig;		/* signature */
	__be16	reSigPad;	/* padding */
	__be32	pmMapBlkCnt;	/* partition blocks count */
	__be32	pmPyPartStart;	/* physical block start of partition */
	__be32	pmPartBlkCnt;	/* physical block count of partition */
	u8	pmPartName[32];	/* (null terminated?) string
				   giving the name of this
				   partition */
	u8	pmPartType[32];	/* (null terminated?) string
				   giving the type of this
				   partition */
	/* a bunch more stuff we don't need */
} __packed;

/*
 * The old style Mac partition map
 *
 * The partition map consists for a 2-byte signature followed by an
 * array of these structures.  The map is terminated with an all-zero
 * one of these.
 */
struct old_pmap {
	__be16		pdSig;	/* Signature bytes */
	struct 	old_pmap_entry {
		__be32	pdStart;
		__be32	pdSize;
		__be32	pdFSID;
	}	pdEntry[42];
} __packed;

/*
 * hfs_part_find()
 *
 * Parse the partition map looking for the
 * start and length of the 'part'th HFS partition.
 */
int hfs_part_find(struct super_block *sb,
		  sector_t *part_start, sector_t *part_size)
{
	struct buffer_head *bh;
	__be16 *data;
	int i, size, res;

	res = -ENOENT;
	bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK, data);
	if (!bh)
		return -EIO;

	switch (be16_to_cpu(*data)) {
	case HFS_OLD_PMAP_MAGIC:
	  {
		struct old_pmap *pm;
		struct old_pmap_entry *p;

		pm = (struct old_pmap *)bh->b_data;
		p = pm->pdEntry;
		size = 42;
		for (i = 0; i < size; p++, i++) {
			if (p->pdStart && p->pdSize &&
			    p->pdFSID == cpu_to_be32(0x54465331)/*"TFS1"*/ &&
			    (HFS_SB(sb)->part < 0 || HFS_SB(sb)->part == i)) {
				*part_start += be32_to_cpu(p->pdStart);
				*part_size = be32_to_cpu(p->pdSize);
				res = 0;
			}
		}
		break;
	  }
	case HFS_NEW_PMAP_MAGIC:
	  {
		struct new_pmap *pm;

		pm = (struct new_pmap *)bh->b_data;
		size = be32_to_cpu(pm->pmMapBlkCnt);
		for (i = 0; i < size;) {
			if (!memcmp(pm->pmPartType,"Apple_HFS", 9) &&
			    (HFS_SB(sb)->part < 0 || HFS_SB(sb)->part == i)) {
				*part_start += be32_to_cpu(pm->pmPyPartStart);
				*part_size = be32_to_cpu(pm->pmPartBlkCnt);
				res = 0;
				break;
			}
			brelse(bh);
			bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK + ++i, pm);
			if (!bh)
				return -EIO;
			if (pm->pmSig != cpu_to_be16(HFS_NEW_PMAP_MAGIC))
				break;
		}
		break;
	  }
	}
	brelse(bh);

	return res;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/hfs/part_tbl.c
	3	*
	4	* Copyright (C) 1996-1997 Paul H. Hargrove
	5	* (C) 2003 Ardis Technologies <[email protected]>
	6	* This file may be distributed under the terms of the GNU General Public License.
	7	*
	8	* Original code to handle the new style Mac partition table based on
	9	* a patch contributed by Holger Schemel ([email protected]).
	10	*/
	11
	12	#include "hfs_fs.h"
	13
	14	/*
	15	* The new style Mac partition map
	16	*
	17	* For each partition on the media there is a physical block (512-byte
	18	* block) containing one of these structures. These blocks are
	19	* contiguous starting at block 1.
	20	*/
	21	struct new_pmap {
	22	__be16 pmSig; /* signature */
	23	__be16 reSigPad; /* padding */
	24	__be32 pmMapBlkCnt; /* partition blocks count */
	25	__be32 pmPyPartStart; /* physical block start of partition */
	26	__be32 pmPartBlkCnt; /* physical block count of partition */
	27	u8 pmPartName[32]; /* (null terminated?) string
	28	giving the name of this
	29	partition */
	30	u8 pmPartType[32]; /* (null terminated?) string
	31	giving the type of this
	32	partition */
	33	/* a bunch more stuff we don't need */
	34	} __packed;
	35
	36	/*
	37	* The old style Mac partition map
	38	*
	39	* The partition map consists for a 2-byte signature followed by an
	40	* array of these structures. The map is terminated with an all-zero
	41	* one of these.
	42	*/
	43	struct old_pmap {
	44	__be16 pdSig; /* Signature bytes */
	45	struct old_pmap_entry {
	46	__be32 pdStart;
	47	__be32 pdSize;
	48	__be32 pdFSID;
	49	} pdEntry[42];
	50	} __packed;
	51
	52	/*
	53	* hfs_part_find()
	54	*
	55	* Parse the partition map looking for the
	56	* start and length of the 'part'th HFS partition.
	57	*/
	58	int hfs_part_find(struct super_block *sb,
	59	sector_t part_start, sector_t part_size)
	60	{
	61	struct buffer_head *bh;
	62	__be16 *data;
	63	int i, size, res;
	64
65	res = -ENOENT;
66	bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK, data);
67	if (!bh)
68	return -EIO;
69
70	switch (be16_to_cpu(*data)) {
71	case HFS_OLD_PMAP_MAGIC:
72	{
73	struct old_pmap *pm;
74	struct old_pmap_entry *p;
75
76	pm = (struct old_pmap *)bh->b_data;
77	p = pm->pdEntry;
78	size = 42;
79	for (i = 0; i < size; p++, i++) {
80	if (p->pdStart && p->pdSize &&
81	p->pdFSID == cpu_to_be32(0x54465331)/"TFS1"/ &&
82	(HFS_SB(sb)->part < 0 \|\| HFS_SB(sb)->part == i)) {
83	*part_start += be32_to_cpu(p->pdStart);
84	*part_size = be32_to_cpu(p->pdSize);
85	res = 0;
86	}
87	}
88	break;
89	}
90	case HFS_NEW_PMAP_MAGIC:
91	{
92	struct new_pmap *pm;
93
94	pm = (struct new_pmap *)bh->b_data;
95	size = be32_to_cpu(pm->pmMapBlkCnt);
96	for (i = 0; i < size;) {
97	if (!memcmp(pm->pmPartType,"Apple_HFS", 9) &&
98	(HFS_SB(sb)->part < 0 \|\| HFS_SB(sb)->part == i)) {
99	*part_start += be32_to_cpu(pm->pmPyPartStart);
100	*part_size = be32_to_cpu(pm->pmPartBlkCnt);
101	res = 0;
102	break;
103	}
104	brelse(bh);
105	bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK + ++i, pm);
106	if (!bh)
107	return -EIO;
108	if (pm->pmSig != cpu_to_be16(HFS_NEW_PMAP_MAGIC))
109	break;
110	}
111	break;
112	}
113	}
114	brelse(bh);
115
116	return res;
117	}