cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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part_tbl.c (2946B)

      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 */
     21struct 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 */
     43struct 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 */
     58int 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}