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158 lines
4.2 KiB
158 lines
4.2 KiB
/* |
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* linux/fs/hfsplus/part_tbl.c |
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* |
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* Copyright (C) 1996-1997 Paul H. Hargrove |
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* This file may be distributed under the terms of |
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* the GNU General Public License. |
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* |
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* Original code to handle the new style Mac partition table based on |
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* a patch contributed by Holger Schemel ([email protected]). |
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* |
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* In function preconditions the term "valid" applied to a pointer to |
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* a structure means that the pointer is non-NULL and the structure it |
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* points to has all fields initialized to consistent values. |
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* |
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*/ |
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#include <linux/slab.h> |
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#include "hfsplus_fs.h" |
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/* offsets to various blocks */ |
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#define HFS_DD_BLK 0 /* Driver Descriptor block */ |
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#define HFS_PMAP_BLK 1 /* First block of partition map */ |
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#define HFS_MDB_BLK 2 /* Block (w/i partition) of MDB */ |
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/* magic numbers for various disk blocks */ |
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#define HFS_DRVR_DESC_MAGIC 0x4552 /* "ER": driver descriptor map */ |
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#define HFS_OLD_PMAP_MAGIC 0x5453 /* "TS": old-type partition map */ |
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#define HFS_NEW_PMAP_MAGIC 0x504D /* "PM": new-type partition map */ |
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#define HFS_SUPER_MAGIC 0x4244 /* "BD": HFS MDB (super block) */ |
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#define HFS_MFS_SUPER_MAGIC 0xD2D7 /* MFS MDB (super block) */ |
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/* |
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* The new style Mac partition map |
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* |
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* For each partition on the media there is a physical block (512-byte |
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* block) containing one of these structures. These blocks are |
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* contiguous starting at block 1. |
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*/ |
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struct new_pmap { |
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__be16 pmSig; /* signature */ |
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__be16 reSigPad; /* padding */ |
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__be32 pmMapBlkCnt; /* partition blocks count */ |
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__be32 pmPyPartStart; /* physical block start of partition */ |
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__be32 pmPartBlkCnt; /* physical block count of partition */ |
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u8 pmPartName[32]; /* (null terminated?) string |
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giving the name of this |
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partition */ |
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u8 pmPartType[32]; /* (null terminated?) string |
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giving the type of this |
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partition */ |
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/* a bunch more stuff we don't need */ |
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} __packed; |
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/* |
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* The old style Mac partition map |
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* |
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* The partition map consists for a 2-byte signature followed by an |
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* array of these structures. The map is terminated with an all-zero |
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* one of these. |
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*/ |
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struct old_pmap { |
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__be16 pdSig; /* Signature bytes */ |
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struct old_pmap_entry { |
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__be32 pdStart; |
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__be32 pdSize; |
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__be32 pdFSID; |
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} pdEntry[42]; |
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} __packed; |
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static int hfs_parse_old_pmap(struct super_block *sb, struct old_pmap *pm, |
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sector_t *part_start, sector_t *part_size) |
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{ |
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struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); |
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int i; |
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for (i = 0; i < 42; i++) { |
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struct old_pmap_entry *p = &pm->pdEntry[i]; |
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if (p->pdStart && p->pdSize && |
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p->pdFSID == cpu_to_be32(0x54465331)/*"TFS1"*/ && |
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(sbi->part < 0 || sbi->part == i)) { |
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*part_start += be32_to_cpu(p->pdStart); |
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*part_size = be32_to_cpu(p->pdSize); |
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return 0; |
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} |
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} |
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return -ENOENT; |
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} |
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static int hfs_parse_new_pmap(struct super_block *sb, void *buf, |
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struct new_pmap *pm, sector_t *part_start, sector_t *part_size) |
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{ |
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struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); |
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int size = be32_to_cpu(pm->pmMapBlkCnt); |
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int buf_size = hfsplus_min_io_size(sb); |
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int res; |
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int i = 0; |
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do { |
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if (!memcmp(pm->pmPartType, "Apple_HFS", 9) && |
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(sbi->part < 0 || sbi->part == i)) { |
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*part_start += be32_to_cpu(pm->pmPyPartStart); |
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*part_size = be32_to_cpu(pm->pmPartBlkCnt); |
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return 0; |
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} |
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if (++i >= size) |
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return -ENOENT; |
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pm = (struct new_pmap *)((u8 *)pm + HFSPLUS_SECTOR_SIZE); |
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if ((u8 *)pm - (u8 *)buf >= buf_size) { |
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res = hfsplus_submit_bio(sb, |
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*part_start + HFS_PMAP_BLK + i, |
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buf, (void **)&pm, REQ_OP_READ, |
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0); |
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if (res) |
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return res; |
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} |
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} while (pm->pmSig == cpu_to_be16(HFS_NEW_PMAP_MAGIC)); |
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return -ENOENT; |
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} |
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/* |
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* Parse the partition map looking for the start and length of a |
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* HFS/HFS+ partition. |
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*/ |
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int hfs_part_find(struct super_block *sb, |
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sector_t *part_start, sector_t *part_size) |
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{ |
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void *buf, *data; |
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int res; |
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buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); |
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if (!buf) |
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return -ENOMEM; |
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res = hfsplus_submit_bio(sb, *part_start + HFS_PMAP_BLK, |
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buf, &data, REQ_OP_READ, 0); |
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if (res) |
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goto out; |
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switch (be16_to_cpu(*((__be16 *)data))) { |
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case HFS_OLD_PMAP_MAGIC: |
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res = hfs_parse_old_pmap(sb, data, part_start, part_size); |
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break; |
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case HFS_NEW_PMAP_MAGIC: |
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res = hfs_parse_new_pmap(sb, buf, data, part_start, part_size); |
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break; |
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default: |
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res = -ENOENT; |
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break; |
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} |
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out: |
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kfree(buf); |
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return res; |
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}
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