/* * 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 <linux/slab.h> #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; static int hfs_parse_old_pmap(struct super_block *sb, struct old_pmap *pm, sector_t *part_start, sector_t *part_size) { struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); int i; for (i = 0; i < 42; i++) { struct old_pmap_entry *p = &pm->pdEntry[i]; if (p->pdStart && p->pdSize && p->pdFSID == cpu_to_be32(0x54465331)/*"TFS1"*/ && (sbi->part < 0 || sbi->part == i)) { *part_start += be32_to_cpu(p->pdStart); *part_size = be32_to_cpu(p->pdSize); return 0; } } return -ENOENT; } static int hfs_parse_new_pmap(struct super_block *sb, void *buf, struct new_pmap *pm, sector_t *part_start, sector_t *part_size) { struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); int size = be32_to_cpu(pm->pmMapBlkCnt); int buf_size = hfsplus_min_io_size(sb); int res; int i = 0; do { if (!memcmp(pm->pmPartType, "Apple_HFS", 9) && (sbi->part < 0 || sbi->part == i)) { *part_start += be32_to_cpu(pm->pmPyPartStart); *part_size = be32_to_cpu(pm->pmPartBlkCnt); return 0; } if (++i >= size) return -ENOENT; pm = (struct new_pmap *)((u8 *)pm + HFSPLUS_SECTOR_SIZE); if ((u8 *)pm - (u8 *)buf >= buf_size) { res = hfsplus_submit_bio(sb, *part_start + HFS_PMAP_BLK + i, buf, (void **)&pm, REQ_OP_READ, 0); if (res) return res; } } while (pm->pmSig == cpu_to_be16(HFS_NEW_PMAP_MAGIC)); return -ENOENT; } /* * Parse the partition map looking for the start and length of a * HFS/HFS+ partition. */ int hfs_part_find(struct super_block *sb, sector_t *part_start, sector_t *part_size) { void *buf, *data; int res; buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL); if (!buf) return -ENOMEM; res = hfsplus_submit_bio(sb, *part_start + HFS_PMAP_BLK, buf, &data, REQ_OP_READ, 0); if (res) goto out; switch (be16_to_cpu(*((__be16 *)data))) { case HFS_OLD_PMAP_MAGIC: res = hfs_parse_old_pmap(sb, data, part_start, part_size); break; case HFS_NEW_PMAP_MAGIC: res = hfs_parse_new_pmap(sb, buf, data, part_start, part_size); break; default: res = -ENOENT; break; } out: kfree(buf); return res; }