patch-2.1.78 linux/fs/hfs/part_tbl.c

• Lines: 245
• Date: Sun Jan 4 10:40:17 1998
• Orig file: v2.1.77/linux/fs/hfs/part_tbl.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.77/linux/fs/hfs/part_tbl.c linux/fs/hfs/part_tbl.c
@@ -0,0 +1,244 @@
+/*
+ * linux/fs/hfs/part_tbl.c
+ *
+ * Copyright (C) 1996-1997  Paul H. Hargrove
+ * This file may be distributed under the terms of the GNU Public License.
+ *
+ * Original code to handle the new style Mac partition table based on
+ * a patch contributed by Holger Schemel (aeglos@valinor.owl.de).
+ *
+ * "XXX" in a comment is a note to myself to consider changing something.
+ *
+ * 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.
+ *
+ * The code in this file initializes some structures which contain
+ * pointers by calling memset(&foo, 0, sizeof(foo)).
+ * This produces the desired behavior only due to the non-ANSI
+ * assumption that the machine representation of NULL is all zeros.
+ */
+
+#include "hfs.h"
+
+/*================ File-local data types ================*/
+
+/*
+ * The Macintosh Driver Descriptor Block
+ *
+ * On partitioned Macintosh media this is block 0.
+ * We really only need the "magic number" to check for partitioned media.
+ */
+struct hfs_drvr_desc {
+	hfs_word_t	ddSig;		/* The signature word */
+	/* a bunch more stuff we don't need */
+};
+
+/* 
+ * 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 {
+	hfs_word_t	pmSig;		/* Signature bytes to verify
+					   that this is a partition
+					   map block */
+	hfs_word_t	reSigPad;	/* padding */
+	hfs_lword_t	pmMapBlkCnt;	/* (At least in block 1) this
+					   is the number of partition
+					   map blocks */
+	hfs_lword_t	pmPyPartStart;	/* The physical block number
+					   of the first block in this
+					   partition */
+	hfs_lword_t	pmPartBlkCnt;	/* The number of physical
+					   blocks in this partition */
+	hfs_byte_t	pmPartName[32];	/* (null terminated?) string
+					   giving the name of this
+					   partition */
+	hfs_byte_t	pmPartType[32];	/* (null terminated?) string
+					   giving the type of this
+					   partition */
+	/* a bunch more stuff we don't need */
+};
+
+/* 
+ * 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 {
+	hfs_word_t		pdSig;	/* Signature bytes */
+	struct 	old_pmap_entry {
+		hfs_lword_t	pdStart;
+		hfs_lword_t	pdSize;
+		hfs_lword_t	pdFSID;
+	}	pdEntry[42];
+};
+
+/*================ File-local functions ================*/
+
+/*
+ * parse_new_part_table()
+ *
+ * Parse a new style partition map looking for the
+ * start and length of the 'part'th HFS partition.
+ */
+static int parse_new_part_table(hfs_sysmdb sys_mdb, hfs_buffer buf,
+				int part, hfs_s32 *size, hfs_s32 *start)
+{
+	struct new_pmap *pm = (struct new_pmap *)hfs_buffer_data(buf);
+	hfs_u32 pmap_entries = hfs_get_hl(pm->pmMapBlkCnt);
+	int hfs_part = 0;
+	int entry;
+
+	for (entry = 0; (entry < pmap_entries) && !(*start); ++entry) {
+		if (entry) {
+			/* read the next partition map entry */
+			buf = hfs_buffer_get(sys_mdb, HFS_PMAP_BLK + entry, 1);
+			if (!hfs_buffer_ok(buf)) {
+				hfs_warn("hfs_fs: unable to "
+				         "read partition map.\n");
+				goto bail;
+			}
+			pm = (struct new_pmap *)hfs_buffer_data(buf);
+			if (hfs_get_ns(pm->pmSig) !=
+						htons(HFS_NEW_PMAP_MAGIC)) {
+				hfs_warn("hfs_fs: invalid "
+				         "entry in partition map\n");
+				hfs_buffer_put(buf);
+				goto bail;
+			}
+		}
+
+		/* look for an HFS partition */
+		if (!memcmp(pm->pmPartType,"Apple_HFS",9) && 
+		    ((hfs_part++) == part)) {
+			/* Found it! */
+			*start = hfs_get_hl(pm->pmPyPartStart);
+			*size = hfs_get_hl(pm->pmPartBlkCnt);
+		}
+
+		hfs_buffer_put(buf);
+	}
+
+	return 0;
+
+bail:
+	return 1;
+}
+
+/*
+ * parse_old_part_table()
+ *
+ * Parse a old style partition map looking for the
+ * start and length of the 'part'th HFS partition.
+ */
+static int parse_old_part_table(hfs_sysmdb sys_mdb, hfs_buffer buf,
+				int part, hfs_s32 *size, hfs_s32 *start)
+{
+	struct old_pmap *pm = (struct old_pmap *)hfs_buffer_data(buf);
+	struct old_pmap_entry *p = &pm->pdEntry[0];
+	int hfs_part = 0;
+
+	while ((p->pdStart || p->pdSize || p->pdFSID) && !(*start)) {
+		/* look for an HFS partition */
+		if ((hfs_get_nl(p->pdFSID) == htonl(0x54465331)/*"TFS1"*/) &&
+		    ((hfs_part++) == part)) {
+			/* Found it! */
+			*start = hfs_get_hl(p->pdStart);
+			*size = hfs_get_hl(p->pdSize);
+		}
+		++p;
+	}
+	hfs_buffer_put(buf);
+
+	return 0;
+}
+
+/*================ Global functions ================*/
+
+/*
+ * hfs_part_find()
+ *
+ * Parse the partition map looking for the
+ * start and length of the 'part'th HFS partition.
+ */
+int hfs_part_find(hfs_sysmdb sys_mdb, int part, int silent,
+		  hfs_s32 *size, hfs_s32 *start)
+{
+	hfs_buffer buf;
+	hfs_u16 sig;
+	int dd_found = 0;
+	int retval = 1;
+
+	/* Read block 0 to see if this media is partitioned */
+	buf = hfs_buffer_get(sys_mdb, HFS_DD_BLK, 1);
+	if (!hfs_buffer_ok(buf)) {
+		hfs_warn("hfs_fs: Unable to read block 0.\n");
+		goto done;
+	}
+	sig = hfs_get_ns(((struct hfs_drvr_desc *)hfs_buffer_data(buf))->ddSig);
+	hfs_buffer_put(buf);
+
+        if (sig == htons(HFS_DRVR_DESC_MAGIC)) {
+		/* We are definitely on partitioned media. */
+		dd_found = 1;
+	}
+
+	buf = hfs_buffer_get(sys_mdb, HFS_PMAP_BLK, 1);
+	if (!hfs_buffer_ok(buf)) {
+		hfs_warn("hfs_fs: Unable to read block 1.\n");
+		goto done;
+	}
+
+	*size = *start = 0;
+
+	switch (hfs_get_ns(hfs_buffer_data(buf))) {
+	case __constant_htons(HFS_OLD_PMAP_MAGIC):
+		retval = parse_old_part_table(sys_mdb, buf, part, size, start);
+		break;
+
+	case __constant_htons(HFS_NEW_PMAP_MAGIC):
+		retval = parse_new_part_table(sys_mdb, buf, part, size, start);
+		break;
+
+	default:
+		if (dd_found) {
+			/* The media claimed to have a partition map */
+			if (!silent) {
+				hfs_warn("hfs_fs: This disk has an "
+					 "unrecognized partition map type.\n");
+			}
+		} else {
+			/* Conclude that the media is not partitioned */
+			retval = 0;
+		}
+		goto done;
+	}
+
+	if (!retval) {
+		if (*start == 0) {
+			if (part) {
+				hfs_warn("hfs_fs: unable to locate "
+				         "HFS partition number %d.\n", part);
+			} else {
+				hfs_warn("hfs_fs: unable to locate any "
+					 "HFS partitions.\n");
+			}
+			retval = 1;
+		} else if (*size < 0) {
+			hfs_warn("hfs_fs: Partition size > 1 Terabyte.\n");
+			retval = 1;
+		} else if (*start < 0) {
+			hfs_warn("hfs_fs: Partition begins beyond 1 "
+				 "Terabyte.\n");
+			retval = 1;
+		}
+	}
+done:
+	return retval;
+}