1 | /* |
2 | * linux/fs/hfs/part_tbl.c |
3 | * |
4 | * Copyright (C) 1996-1997 Paul H. Hargrove |
5 | * (C) 2003 Ardis Technologies <roman@ardistech.com> |
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 (aeglos@valinor.owl.de). |
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(p: pm->pmPartType,q: "Apple_HFS" , size: 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 | } |
118 | |