blob: 1528a6fd02992f1858ee254fe01039520da77bd4 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/*
* linux/fs/hfsplus/part_tbl.c
*
* Copyright (C) 1996-1997 Paul H. Hargrove
* 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 (aeglos@valinor.owl.de).
*
* In function preconditions the term "valid" applied to a pointer to
* a structure means that the pointer is non-NULL and the structure it
* points to has all fields initialized to consistent values.
*
*/
#include "hfsplus_fs.h"
/* offsets to various blocks */
#define HFS_DD_BLK 0 /* Driver Descriptor block */
#define HFS_PMAP_BLK 1 /* First block of partition map */
#define HFS_MDB_BLK 2 /* Block (w/i partition) of MDB */
/* magic numbers for various disk blocks */
#define HFS_DRVR_DESC_MAGIC 0x4552 /* "ER": driver descriptor map */
#define HFS_OLD_PMAP_MAGIC 0x5453 /* "TS": old-type partition map */
#define HFS_NEW_PMAP_MAGIC 0x504D /* "PM": new-type partition map */
#define HFS_SUPER_MAGIC 0x4244 /* "BD": HFS MDB (super block) */
#define HFS_MFS_SUPER_MAGIC 0xD2D7 /* MFS MDB (super block) */
/*
* 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"*/ &&
(HFSPLUS_SB(sb).part < 0 || HFSPLUS_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) &&
(HFSPLUS_SB(sb).part < 0 || HFSPLUS_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;
}
|
