1 files changed, 133 insertions, 0 deletions
diff --git a/fs/hfsplus/part_tbl.c b/fs/hfsplus/part_tbl.c
new file mode 100644
index 00000000000..ae783066fc3
--- /dev/null
+++ b/fs/hfsplus/part_tbl.c
@@ -0,0 +1,133 @@
+/*
+ * linux/fs/hfs/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 "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;
+
+/*
+ * hfs_part_find()
+ *
+ * Parse the partition map looking for the
+ * start and length of the 'part'th HFS partition.
+ */
+int hfs_part_find(struct super_block *sb,
+		  sector_t *part_start, sector_t *part_size)
+{
+	struct buffer_head *bh;
+	__be16 *data;
+	int i, size, res;
+
+	res = -ENOENT;
+	bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK, data);
+	if (!bh)
+		return -EIO;
+
+	switch (be16_to_cpu(*data)) {
+	case HFS_OLD_PMAP_MAGIC:
+	  {
+		struct old_pmap *pm;
+		struct old_pmap_entry *p;
+
+		pm = (struct old_pmap *)bh->b_data;
+		p = pm->pdEntry;
+		size = 42;
+		for (i = 0; i < size; p++, i++) {
+			if (p->pdStart && p->pdSize &&
+			    p->pdFSID == cpu_to_be32(0x54465331)/*"TFS1"*/ &&
+			    (HFSPLUS_SB(sb).part < 0 || HFSPLUS_SB(sb).part == i)) {
+				*part_start += be32_to_cpu(p->pdStart);
+				*part_size = be32_to_cpu(p->pdSize);
+				res = 0;
+			}
+		}
+		break;
+	  }
+	case HFS_NEW_PMAP_MAGIC:
+	  {
+		struct new_pmap *pm;
+
+		pm = (struct new_pmap *)bh->b_data;
+		size = be32_to_cpu(pm->pmMapBlkCnt);
+		for (i = 0; i < size;) {
+			if (!memcmp(pm->pmPartType,"Apple_HFS", 9) &&
+			    (HFSPLUS_SB(sb).part < 0 || HFSPLUS_SB(sb).part == i)) {
+				*part_start += be32_to_cpu(pm->pmPyPartStart);
+				*part_size = be32_to_cpu(pm->pmPartBlkCnt);
+				res = 0;
+				break;
+			}
+			brelse(bh);
+			bh = sb_bread512(sb, *part_start + HFS_PMAP_BLK + ++i, pm);
+			if (!bh)
+				return -EIO;
+			if (pm->pmSig != cpu_to_be16(HFS_NEW_PMAP_MAGIC))
+				break;
+		}
+		break;
+	  }
+	}
+	brelse(bh);
+
+	return res;
+}