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 } 118