| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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(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 | } |