patch-2.4.8 linux/fs/partitions/ldm.c

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diff -u --recursive --new-file v2.4.7/linux/fs/partitions/ldm.c linux/fs/partitions/ldm.c
@@ -0,0 +1,980 @@
+/*
+ * $Id: ldm.c,v 1.25 2001/07/25 23:32:02 flatcap Exp $
+ *
+ * ldm - Part of the Linux-NTFS project.
+ *
+ * Copyright (C) 2001 Richard Russon <ntfs@flatcap.org>
+ * Copyright (C) 2001 Anton Altaparmakov <antona@users.sf.net>
+ *
+ * Documentation is available at http://linux-ntfs.sf.net/ldm
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (in the main directory of the Linux-NTFS source
+ * in the file COPYING); if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include <asm/types.h>
+#include <asm/unaligned.h>
+#include <asm/byteorder.h>
+#include <linux/genhd.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include "check.h"
+#include "ldm.h"
+#include "msdos.h"
+
+#if 0 /* Fool kernel-doc since it doesn't do macros yet. */
+/**
+ * ldm_debug - output an error message if debugging was enabled at compile time
+ * @f:		a printf format string containing the message
+ * @...:	the variables to substitute into @f
+ *
+ * ldm_debug() writes a DEBUG level message to the syslog but only if the
+ * driver was compiled with debug enabled. Otherwise, the call turns into a NOP.
+ */
+static void ldm_debug(const char *f, ...);
+#endif
+#ifdef CONFIG_LDM_DEBUG
+#define ldm_debug(f, a...)						\
+	{								\
+		printk(LDM_DEBUG " DEBUG (%s, %d): %s: ",		\
+				__FILE__, __LINE__, __FUNCTION__);	\
+		printk(f, ##a);						\
+	}
+#else	/* !CONFIG_LDM_DEBUG */
+#define ldm_debug(f, a...)	do {} while (0)
+#endif	/* !CONFIG_LDM_DEBUG */
+
+/* Necessary forward declarations. */
+static int create_partition(struct gendisk *, int, int, int);
+static int parse_privhead(const u8 *, struct privhead *);
+static u64 get_vnum(const u8 *, int *);
+static int get_vstr(const u8 *, u8 *, const int);
+
+/**
+ * parse_vblk_part - parse a LDM database vblk partition record
+ * @buffer:	vblk partition record loaded from the LDM database
+ * @buf_size:	size of @buffer in bytes
+ * @vb:		in memory vblk structure to return parsed information in
+ *
+ * This parses the LDM database vblk record of type VBLK_PART, i.e. a partition
+ * record, supplied in @buffer and sets up the in memory vblk structure @vb
+ * with the obtained information.
+ *
+ * Return 1 on success and -1 on error, in which case @vb is undefined.
+ */
+static int parse_vblk_part(const u8 *buffer, const int buf_size,
+		struct vblk *vb)
+{
+	int err, rel_objid, rel_name, rel_size, rel_parent;
+
+	if (0x34 >= buf_size)
+		return -1;
+	/* Calculate relative offsets. */
+	rel_objid  = 1 + buffer[0x18];
+	if (0x18 + rel_objid >= buf_size)
+		return -1;
+	rel_name   = 1 + buffer[0x18 + rel_objid] + rel_objid;
+	if (0x34 + rel_name >= buf_size)
+		return -1;
+	rel_size   = 1 + buffer[0x34 + rel_name] + rel_name;
+	if (0x34 + rel_size >= buf_size)
+		return -1;
+	rel_parent = 1 + buffer[0x34 + rel_size] + rel_size;
+	if (0x34 + rel_parent >= buf_size)
+		return -1;
+	/* Setup @vb. */
+	vb->vblk_type    = VBLK_PART;
+	vb->obj_id       = get_vnum(buffer + 0x18, &err);
+	if (err || 0x34 + rel_parent + buffer[0x34 + rel_parent] >= buf_size)
+		return -1;
+	vb->disk_id      = get_vnum(buffer + 0x34 + rel_parent, &err);
+	if (err || 0x24 + rel_name + 8 > buf_size)
+		return -1;
+	vb->start_sector = BE64(buffer + 0x24 + rel_name);
+	if (0x34 + rel_name + buffer[0x34 + rel_name] >= buf_size)
+		return -1;
+	vb->num_sectors  = get_vnum(buffer + 0x34 + rel_name, &err);
+	if (err || 0x18 + rel_objid + buffer[0x18 + rel_objid] >= buf_size)
+		return -1;
+	err = get_vstr(buffer + 0x18 + rel_objid, vb->name, sizeof(vb->name));
+	if (err == -1)
+		return err;
+	ldm_debug("Parsed Partition VBLK successfully.\n");
+	return 1;
+}
+
+/**
+ * parse_vblk - parse a LDM database vblk record
+ * @buffer:	vblk record loaded from the LDM database
+ * @buf_size:	size of @buffer in bytes
+ * @vb:		in memory vblk structure to return parsed information in
+ *
+ * This parses the LDM database vblk record supplied in @buffer and sets up
+ * the in memory vblk structure @vb with the obtained information.
+ *
+ * Return 1 on success, 0 if successful but record not in use, and -1 on error.
+ * If the return value is 0 or -1, @vb is undefined.
+ *
+ * NOTE: Currently the only record type we handle is VBLK_PART, i.e. records
+ * describing a partition. For all others, we just set @vb->vblk_type to 0 and
+ * return success. This of course means that if @vb->vblk_type is zero, all
+ * other fields in @vb are undefined.
+ */
+static int parse_vblk(const u8 *buffer, const int buf_size, struct vblk *vb)
+{
+	int err = 1;
+
+	if (buf_size < 0x14)
+		return -1;
+	if (MAGIC_VBLK != BE32(buffer)) {
+		printk(LDM_CRIT "Cannot find VBLK, database may be corrupt.\n");
+		return -1;
+	}
+	if (BE16(buffer + 0x0E) == 0)	/* Record is not in use. */
+		return 0;
+	/* FIXME: What about extended VBLKs? */
+	switch (buffer[0x13]) {
+	case VBLK_PART:
+		err = parse_vblk_part(buffer, buf_size, vb);
+		break;
+	default:
+		vb->vblk_type = 0;
+	}
+	if (err != -1)
+		ldm_debug("Parsed VBLK successfully.\n");
+	return err;
+}
+
+/**
+ * create_data_partitions - create the data partition devices
+ * @hd:			gendisk structure in which to create the data partitions
+ * @first_sector:	first sector within the disk device
+ * @first_part_minor:	first minor number of data partition devices
+ * @dev:		partition device holding the LDM database
+ * @vm:			in memory vmdb structure of @dev
+ * @ph:			in memory privhead structure of the disk device
+ * @dk:			in memory ldmdisk structure of the disk device
+ *
+ * The database contains ALL the partitions for ALL the disks, so we need to
+ * filter out this specific disk. Using the disk's object id, we can find all
+ * the partitions in the database that belong to this disk.
+ *
+ * For each found partition, we create a corresponding partition device starting
+ * with minor number @first_part_minor.
+ *
+ * Return 1 on success and -1 on error.
+ */
+static int create_data_partitions(struct gendisk *hd,
+		const unsigned long first_sector, int first_part_minor,
+		const kdev_t dev, const struct vmdb *vm,
+		const struct privhead *ph, const struct ldmdisk *dk)
+{
+	struct buffer_head *bh;
+	struct vblk *vb;
+	int vblk;
+	int vsize;		/* VBLK size. */
+	int perbuf;		/* VBLKs per buffer. */
+	int buffer, lastbuf, lastofs, err;
+
+	vb = (struct vblk*)kmalloc(sizeof(struct vblk), GFP_KERNEL);
+	if (!vb)
+		goto no_mem;
+	vsize   = vm->vblk_size;
+	if (vsize < 1 || vsize > LDM_BLOCKSIZE)
+		goto err_out;
+	perbuf  = LDM_BLOCKSIZE / vsize;
+	if (perbuf < 1 || LDM_BLOCKSIZE % vsize)
+		goto err_out;
+					/* 512 == VMDB size */
+	lastbuf = (vm->last_vblk_seq - (512 / vsize)) / perbuf;
+	lastofs = (vm->last_vblk_seq - (512 / vsize)) % perbuf;
+	if (lastofs)
+		lastbuf++;
+	if (OFF_VBLK * LDM_BLOCKSIZE + vm->last_vblk_seq * vsize >
+			ph->config_size * 512)
+		goto err_out;
+	printk(" <");
+	for (buffer = 0; buffer < lastbuf; buffer++) {
+		if (!(bh = bread(dev, buffer + OFF_VBLK, LDM_BLOCKSIZE)))
+			goto read_err;
+		for (vblk = 0; vblk < perbuf; vblk++) {
+			u8 *block;
+			
+			if (lastofs && buffer == lastbuf - 1 && vblk >= lastofs)
+				break;
+			block = bh->b_data + vsize * vblk;
+			if (block + vsize > (u8*)bh->b_data + LDM_BLOCKSIZE)
+				goto brelse_out;
+			if (parse_vblk(block, LDM_BLOCKSIZE, vb) != 1)
+				continue;
+			if (vb->vblk_type != VBLK_PART)
+				continue;
+			if (dk->obj_id != vb->disk_id)
+				continue;
+			if (create_partition(hd, first_part_minor,
+					first_sector + vb->start_sector +
+					ph->logical_disk_start,
+					vb->num_sectors) == 1)
+				first_part_minor++;
+		}
+		brelse(bh);
+	}
+	printk(" >\n");
+	err = 1;
+out:
+	kfree(vb);
+	return err;
+brelse_out:
+	brelse(bh);
+	goto err_out;
+no_mem:
+	printk(LDM_CRIT "Not enough memory to allocate required buffers.\n");
+	goto err_out;
+read_err:
+	printk(LDM_CRIT "Disk read failed in create_partitions.\n");
+err_out:
+	err = -1;
+	goto out;
+}
+
+/**
+ * get_vnum - convert a variable-width, big endian number, to cpu u64 one
+ * @block:	pointer to the variable-width number to convert
+ * @err:	address of an integer into which to return the error code.
+ *
+ * This converts a variable-width, big endian number into a 64-bit, CPU format
+ * number and returns the result with err set to 0. If an error occurs return 0
+ * with err set to -1.
+ *
+ * The first byte of a variable-width number is the size of the number in bytes.
+ */
+static u64 get_vnum(const u8 *block, int *err)
+{
+	u64 tmp = 0ULL;
+	u8 length = *block++;
+
+	if (length && length <= 8) {
+		while (length--)
+			tmp = (tmp << 8) | *block++;
+		*err = 0;
+	} else {
+		printk(LDM_ERR "Illegal length in get_vnum(): %d.\n", length);
+		*err = 1;
+	}
+	return tmp;
+}
+
+/**
+ * get_vstr - convert a counted, non-null-terminated ASCII string to C-style one
+ * @block:	string to convert
+ * @buffer:	output buffer
+ * @buflen:	size of output buffer
+ *
+ * This converts @block, a counted, non-null-terminated ASCII string, into a
+ * C-style, null-terminated, ASCII string and returns this in @buffer. The
+ * maximum number of characters converted is given by @buflen.
+ *
+ * The first bytes of a counted string stores the length of the string in bytes.
+ *
+ * Return the number of characters written to @buffer, not including the
+ * terminating null character, on success, and -1 on error, in which case
+ * @buffer is not defined.
+ */
+static int get_vstr(const u8 *block, u8 *buffer, const int buflen)
+{
+	int length = block[0];
+
+	if (length < 1)
+		return -1;
+	if (length >= buflen) {
+		printk(LDM_ERR "String too long for buffer in get_vstr(): "
+				"(%d/%d). Truncating.\n", length, buflen);
+		length = buflen - 1;
+	}
+	memcpy(buffer, block + 1, length);
+	buffer[length] = (u8)'\0';
+	return length;
+}
+
+/**
+ * get_disk_objid - obtain the object id for the device we are working on
+ * @dev:	partition device holding the LDM database
+ * @vm:		in memory vmdb structure of the LDM database
+ * @ph:		in memory privhead structure of the device we are working on
+ * @dk:		in memory ldmdisk structure to return information into
+ *
+ * This obtains the object id for the device we are working on as defined by
+ * the private header @ph. The obtained object id, together with the disk's
+ * GUID from @ph are returned in the ldmdisk structure pointed to by @dk.
+ *
+ * A Disk has two Ids. The main one is a GUID in string format. The second,
+ * used internally for cross-referencing, is a small, sequentially allocated,
+ * number. The PRIVHEAD, just after the partition table, tells us the disk's
+ * GUID. To find the disk's object id, we have to look through the database.
+ *
+ * Return 1 on success and -1 on error, in which case @dk is undefined.
+ */
+static int get_disk_objid(const kdev_t dev, const struct vmdb *vm,
+		const struct privhead *ph, struct ldmdisk *dk)
+{
+	struct buffer_head *bh;
+	u8 *disk_id;
+	int vblk;
+	int vsize;		/* VBLK size. */
+	int perbuf;		/* VBLKs per buffer. */
+	int buffer, lastbuf, lastofs, err;
+
+	disk_id = (u8*)kmalloc(DISK_ID_SIZE, GFP_KERNEL);
+	if (!disk_id)
+		goto no_mem;
+	vsize   = vm->vblk_size;
+	if (vsize < 1 || vsize > LDM_BLOCKSIZE)
+		goto err_out;
+	perbuf  = LDM_BLOCKSIZE / vsize;
+	if (perbuf < 1 || LDM_BLOCKSIZE % vsize)
+		goto err_out;
+					/* 512 == VMDB size */
+	lastbuf = (vm->last_vblk_seq - (512 / vsize)) / perbuf;
+	lastofs = (vm->last_vblk_seq - (512 / vsize)) % perbuf;
+	if (lastofs)
+		lastbuf++;
+	if (OFF_VBLK * LDM_BLOCKSIZE + vm->last_vblk_seq * vsize >
+			ph->config_size * 512)
+		goto err_out;
+	for (buffer = 0; buffer < lastbuf; buffer++) {
+		if (!(bh = bread(dev, buffer + OFF_VBLK, LDM_BLOCKSIZE)))
+			goto read_err;
+		for (vblk = 0; vblk < perbuf; vblk++) {
+			int rel_objid, rel_name, delta;
+			u8 *block;
+
+			if (lastofs && buffer == lastbuf - 1 && vblk >= lastofs)
+				break;
+			block = bh->b_data + vblk * vsize;
+			delta = vblk * vsize + 0x18;
+			if (delta >= LDM_BLOCKSIZE)
+				goto brelse_out;
+			if (block[0x13] != VBLK_DISK)
+				continue;
+			/* Calculate relative offsets. */
+			rel_objid = 1 + block[0x18];
+			if (delta + rel_objid >= LDM_BLOCKSIZE)
+				goto brelse_out;
+			rel_name  = 1 + block[0x18 + rel_objid] + rel_objid;
+			if (delta + rel_name >= LDM_BLOCKSIZE ||
+			    delta + rel_name + block[0x18 + rel_name] >=
+					LDM_BLOCKSIZE)
+				goto brelse_out;
+			err = get_vstr(block + 0x18 + rel_name, disk_id,
+					DISK_ID_SIZE);
+			if (err == -1)
+				goto brelse_out;
+			if (!strncmp(disk_id, ph->disk_id, DISK_ID_SIZE)) {
+				dk->obj_id = get_vnum(block + 0x18, &err);
+				brelse(bh);
+				if (err)
+					goto out;
+				strncpy(dk->disk_id, ph->disk_id,
+						sizeof(dk->disk_id));
+				dk->disk_id[sizeof(dk->disk_id) - 1] = (u8)'\0';
+				err = 1;
+				goto out;
+			}
+		}
+		brelse(bh);
+	}
+	err = -1;
+out:
+	kfree(disk_id);
+	return err;
+brelse_out:
+	brelse(bh);
+	goto err_out;
+no_mem:
+	printk(LDM_CRIT "Not enough memory to allocate required buffers.\n");
+	goto err_out;
+read_err:
+	printk(LDM_CRIT "Disk read failed in get_disk_objid.\n");
+err_out:
+	err = -1;
+	goto out;
+}
+
+/**
+ * parse_vmdb - parse the LDM database vmdb structure
+ * @buffer:	LDM database vmdb structure loaded from the device
+ * @vm:		in memory vmdb structure to return parsed information in
+ *
+ * This parses the LDM database vmdb structure supplied in @buffer and sets up
+ * the in memory vmdb structure @vm with the obtained information.
+ *
+ * Return 1 on success and -1 on error, in which case @vm is undefined.
+ *
+ * NOTE: The *_start, *_size and *_seq values returned in @vm have not been
+ * checked for validity, so make sure to check them when using them.
+ */
+static int parse_vmdb(const u8 *buffer, struct vmdb *vm)
+{
+	if (MAGIC_VMDB != BE32(buffer)) {
+		printk(LDM_CRIT "Cannot find VMDB, database may be corrupt.\n");
+		return -1;
+	}
+	vm->ver_major = BE16(buffer + 0x12);
+	vm->ver_minor = BE16(buffer + 0x14);
+	if ((vm->ver_major != 4) || (vm->ver_minor != 10)) {
+		printk(LDM_ERR "Expected VMDB version %d.%d, got %d.%d. "
+				"Aborting.\n", 4, 10, vm->ver_major,
+				vm->ver_minor);
+		return -1;
+	}
+	vm->vblk_size	  = BE32(buffer + 0x08);
+	vm->vblk_offset   = BE32(buffer + 0x0C);
+	vm->last_vblk_seq = BE32(buffer + 0x04);
+
+	ldm_debug("Parsed VMDB successfully.\n");
+	return 1;
+}
+
+/**
+ * validate_vmdb - validate the vmdb
+ * @dev:	partition device holding the LDM database
+ * @vm:		in memory vmdb in which to return information
+ *
+ * Find the vmdb of the LDM database stored on @dev and return the parsed
+ * information into @vm.
+ *
+ * Return 1 on success and -1 on error, in which case @vm is undefined.
+ */
+static int validate_vmdb(const kdev_t dev, struct vmdb *vm)
+{
+	struct buffer_head *bh;
+	int ret;
+
+	if (!(bh = bread(dev, OFF_VMDB, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT "Disk read failed in validate_vmdb.\n");
+		return -1;
+	}
+	ret = parse_vmdb(bh->b_data + 0x200, vm);
+	brelse(bh);
+	return ret;
+}
+
+/**
+ * compare_tocblocks - compare two tables of contents
+ * @toc1:	first toc
+ * @toc2:	second toc
+ *
+ * This compares the two tables of contents @toc1 and @toc2.
+ *
+ * Return 1 if @toc1 and @toc2 are equal and -1 otherwise.
+ */
+static int compare_tocblocks(const struct tocblock *toc1,
+		const struct tocblock *toc2)
+{
+	if ((toc1->bitmap1_start == toc2->bitmap1_start)	&&
+	    (toc1->bitmap1_size  == toc2->bitmap1_size)		&&
+	    (toc1->bitmap2_start == toc2->bitmap2_start)	&&
+	    (toc1->bitmap2_size  == toc2->bitmap2_size)		&&
+	    !strncmp(toc1->bitmap1_name, toc2->bitmap1_name,
+			sizeof(toc1->bitmap1_name))		&&
+	    !strncmp(toc1->bitmap2_name, toc2->bitmap2_name,
+			sizeof(toc1->bitmap2_name)))
+		return 1;
+	return -1;
+}
+
+/**
+ * parse_tocblock - parse the LDM database table of contents structure
+ * @buffer:	LDM database toc structure loaded from the device
+ * @toc:	in memory toc structure to return parsed information in
+ *
+ * This parses the LDM database table of contents structure supplied in @buffer
+ * and sets up the in memory table of contents structure @toc with the obtained
+ * information.
+ *
+ * Return 1 on success and -1 on error, in which case @toc is undefined.
+ *
+ * FIXME: The *_start and *_size values returned in @toc are not been checked
+ * for validity but as we don't use the actual values for anything other than
+ * comparing between the toc and its backups, the values are not important.
+ */
+static int parse_tocblock(const u8 *buffer, struct tocblock *toc)
+{
+	if (MAGIC_TOCBLOCK != BE64(buffer)) {
+		printk(LDM_CRIT "Cannot find TOCBLOCK, database may be "
+				"corrupt.\n");
+		return -1;
+	}
+	strncpy(toc->bitmap1_name, buffer + 0x24, sizeof(toc->bitmap1_name));
+	toc->bitmap1_name[sizeof(toc->bitmap1_name) - 1] = (u8)'\0';
+	toc->bitmap1_start = BE64(buffer + 0x2E);
+	toc->bitmap1_size  = BE64(buffer + 0x36);
+	/*toc->bitmap1_flags = BE64(buffer + 0x3E);*/
+	if (strncmp(toc->bitmap1_name, TOC_BITMAP1,
+			sizeof(toc->bitmap1_name)) != 0) {
+		printk(LDM_CRIT "TOCBLOCK's first bitmap should be %s, but is "
+				"%s.\n", TOC_BITMAP1, toc->bitmap1_name);
+		return -1;
+	}
+	strncpy(toc->bitmap2_name, buffer + 0x46, sizeof(toc->bitmap2_name));
+	toc->bitmap2_name[sizeof(toc->bitmap2_name) - 1] = (u8)'\0';
+	toc->bitmap2_start = BE64(buffer + 0x50);
+	toc->bitmap2_size  = BE64(buffer + 0x58);
+	/*toc->bitmap2_flags = BE64(buffer + 0x60);*/
+	if (strncmp(toc->bitmap2_name, TOC_BITMAP2,
+			sizeof(toc->bitmap2_name)) != 0) {
+		printk(LDM_CRIT "TOCBLOCK's second bitmap should be %s, but is "
+				"%s.\n", TOC_BITMAP2, toc->bitmap2_name);
+		return -1;
+	}
+	ldm_debug("Parsed TOCBLOCK successfully.\n");
+	return 1;
+}
+
+/**
+ * validate_tocblocks - validate the table of contents and its backups
+ * @dev:	partition device holding the LDM database
+ * @toc1:	in memory table of contents in which to return information
+ *
+ * Find and compare the four tables of contents of the LDM database stored on
+ * @dev and return the parsed information into @toc1.
+ *
+ * Return 1 on success and -1 on error, in which case @toc1 is undefined.
+ */
+static int validate_tocblocks(const kdev_t devdb, struct tocblock *toc1)
+{
+	struct buffer_head *bh;
+	struct tocblock *toc2 = NULL, *toc3 = NULL, *toc4 = NULL;
+	int err;
+
+	toc2 = (struct tocblock*)kmalloc(sizeof(*toc2), GFP_KERNEL);
+	if (!toc2)
+		goto no_mem;
+	toc3 = (struct tocblock*)kmalloc(sizeof(*toc3), GFP_KERNEL);
+	if (!toc3)
+		goto no_mem;
+	toc4 = (struct tocblock*)kmalloc(sizeof(*toc4), GFP_KERNEL);
+	if (!toc4)
+		goto no_mem;
+	/* Read and parse first toc. */
+	if (!(bh = bread(devdb, OFF_TOCBLOCK1, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT "Disk read 1 failed in validate_tocblocks.\n");
+		goto err_out;
+	}
+	err = parse_tocblock(bh->b_data + 0x0200, toc1);
+	brelse(bh);
+	if (err != 1)
+		goto out;
+	/* Read and parse second toc. */
+	if (!(bh = bread(devdb, OFF_TOCBLOCK2, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT "Disk read 2 failed in validate_tocblocks.\n");
+		goto err_out;
+	}
+	err = parse_tocblock(bh->b_data, toc2);
+	brelse(bh);
+	if (err != 1)
+		goto out;
+	/* Read and parse third toc. */
+	if (!(bh = bread(devdb, OFF_TOCBLOCK3, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT "Disk read 3 failed in validate_tocblocks.\n");
+		goto err_out;
+	}
+	err = parse_tocblock(bh->b_data + 0x0200, toc3);
+	brelse(bh);
+	if (err != 1)
+		goto out;
+	/* Read and parse fourth toc. */
+	if (!(bh = bread(devdb, OFF_TOCBLOCK4, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT "Disk read 4 failed in validate_tocblocks.\n");
+		goto err_out;
+	}
+	err = parse_tocblock(bh->b_data, toc4);
+	brelse(bh);
+	if (err != 1)
+		goto out;
+	/* Compare all tocs. */
+	err = compare_tocblocks(toc1, toc2);
+	if (err != 1) {
+		printk(LDM_CRIT "First and second TOCBLOCKs don't match.\n");
+		goto out;
+	}
+	err = compare_tocblocks(toc3, toc4);
+	if (err != 1) {
+		printk(LDM_CRIT "Third and fourth TOCBLOCKs don't match.\n");
+		goto out;
+	}
+	err = compare_tocblocks(toc1, toc3);
+	if (err != 1)
+		printk(LDM_CRIT "First and third TOCBLOCKs don't match.\n");
+	else
+		ldm_debug("Validated TOCBLOCKs successfully.\n");
+out:
+	kfree(toc2);
+	kfree(toc3);
+	kfree(toc4);
+	return err;
+no_mem:
+	printk(LDM_CRIT "Not enough memory to allocate required buffers.\n");
+err_out:
+	err = -1;
+	goto out;
+}
+
+/**
+ * compare_privheads - compare two privheads
+ * @ph1:	first privhead
+ * @ph2:	second privhead
+ *
+ * This compares the two privheads @ph1 and @ph2.
+ *
+ * Return 1 if @ph1 and @ph2 are equal and -1 otherwise.
+ */
+static int compare_privheads(const struct privhead *ph1,
+		const struct privhead *ph2)
+{
+	if ((ph1->ver_major == ph2->ver_major)			 &&
+	    (ph1->ver_minor == ph2->ver_minor)			 &&
+	    (ph1->logical_disk_start == ph2->logical_disk_start) &&
+	    (ph1->logical_disk_size  == ph2->logical_disk_size)	 &&
+	    (ph1->config_start == ph2->config_start)		 &&
+	    (ph1->config_size  == ph2->config_size)		 &&
+	    !strncmp(ph1->disk_id, ph2->disk_id, sizeof(ph1->disk_id)))
+		return 1;
+	return -1;
+}
+
+/**
+ * validate_privheads - compare the privhead backups to the first one
+ * @dev:	partition device holding the LDM database
+ * @ph1:	first privhead which we have already validated before
+ *
+ * We already have one privhead from the beginning of the disk.
+ * Now we compare the two other copies for safety.
+ *
+ * Return 1 on succes and -1 on error.
+ */
+static int validate_privheads(const kdev_t dev, const struct privhead *ph1)
+{
+	struct buffer_head *bh;
+	struct privhead *ph2 = NULL, *ph3 = NULL;
+	int err;
+
+	ph2 = (struct privhead*)kmalloc(sizeof(*ph2), GFP_KERNEL);
+	if (!ph2)
+		goto no_mem;
+	ph3 = (struct privhead*)kmalloc(sizeof(*ph3), GFP_KERNEL);
+	if (!ph3)
+		goto no_mem;
+	if (!(bh = bread(dev, OFF_PRIVHEAD2, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT "Disk read 1 failed in validate_privheads.\n");
+		goto err_out;
+	}
+	err = parse_privhead(bh->b_data, ph2);
+	brelse(bh);
+	if (err != 1)
+		goto out;
+	if (!(bh = bread(dev, OFF_PRIVHEAD3, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT "Disk read 2 failed in validate_privheads.\n");
+		goto err_out;
+	}
+	err = parse_privhead(bh->b_data + 0x0200, ph3);
+	brelse(bh);
+	if (err != 1)
+		goto out;
+	err = compare_privheads(ph1, ph2);
+	if (err != 1) {
+		printk(LDM_CRIT "First and second PRIVHEADs don't match.\n");
+		goto out;
+	}
+	err = compare_privheads(ph1, ph3);
+	if (err != 1)
+		printk(LDM_CRIT "First and third PRIVHEADs don't match.\n");
+	else
+		/* We _could_ have checked more. */
+		ldm_debug("Validated PRIVHEADs successfully.\n");
+out:
+	kfree(ph2);
+	kfree(ph3);
+	return err;
+no_mem:
+	printk(LDM_CRIT "Not enough memory to allocate required buffers.\n");
+err_out:
+	err = -1;
+	goto out;
+}
+
+/**
+ * create_partition - validate input and create a kernel partition device
+ * @hd:		gendisk structure in which to create partition
+ * @minor:	minor number for device to create
+ * @start:	starting offset of the partition into the parent device
+ * @size:	size of the partition
+ *
+ * This validates the range, then puts an entry into the kernel's partition
+ * table.
+ *
+ * @start and @size are numbers of sectors.
+ *
+ * Return 1 on succes and -1 on error.
+ */
+static int create_partition(struct gendisk *hd, const int minor,
+		const int start, const int size)
+{
+	int disk_minor;
+
+	if (!hd->part)
+		return -1;
+	/*
+	 * Get the minor number of the parent device so we can check we don't
+	 * go beyond the end of the device.
+	 */
+	disk_minor = (minor >> hd->minor_shift) << hd->minor_shift;
+	if ((start < 1) || ((start + size) > hd->part[disk_minor].nr_sects)) {
+		printk(LDM_CRIT "LDM Partition exceeds physical disk. "
+				"Aborting.\n");
+		return -1;
+	}
+	add_gd_partition(hd, minor, start, size);
+	ldm_debug("Created partition successfully.\n");
+	return 1;
+}
+
+/**
+ * parse_privhead - parse the LDM database PRIVHEAD structure
+ * @buffer:	LDM database privhead structure loaded from the device
+ * @ph:		in memory privhead structure to return parsed information in
+ *
+ * This parses the LDM database PRIVHEAD structure supplied in @buffer and
+ * sets up the in memory privhead structure @ph with the obtained information.
+ *
+ * Return 1 on succes and -1 on error, in which case @ph is undefined.
+ */
+static int parse_privhead(const u8 *buffer, struct privhead *ph)
+{
+	if (MAGIC_PRIVHEAD != BE64(buffer)) {
+		printk(LDM_ERR "Cannot find PRIVHEAD structure. LDM database "
+				"is corrupt. Aborting.\n");
+		return -1;
+	}
+	ph->ver_major = BE16(buffer + 0x000C);
+	ph->ver_minor = BE16(buffer + 0x000E);
+	if ((ph->ver_major != 2) || (ph->ver_minor != 11)) {
+		printk(LDM_ERR "Expected PRIVHEAD version %d.%d, got %d.%d. "
+				"Aborting.\n", 2, 11, ph->ver_major,
+				ph->ver_minor);
+		return -1;
+	}
+	ph->config_start = BE64(buffer + 0x012B);
+	ph->config_size  = BE64(buffer + 0x0133);
+	if (ph->config_size != LDM_DB_SIZE) {	/* 1 MiB in sectors. */
+		printk(LDM_ERR "Database should be %u bytes, claims to be %Lu "
+				"bytes. Aborting.\n", LDM_DB_SIZE,
+				ph->config_size);
+		return -1;
+	}
+	ph->logical_disk_start = BE64(buffer + 0x011B);
+	ph->logical_disk_size  = BE64(buffer + 0x0123);
+	if (!ph->logical_disk_size ||
+	    ph->logical_disk_start + ph->logical_disk_size > ph->config_start)
+		return -1;
+
+	memcpy(ph->disk_id, buffer + 0x0030, sizeof(ph->disk_id));
+
+	ldm_debug("Parsed PRIVHEAD successfully.\n");
+	return 1;
+}
+
+/**
+ * create_db_partition - create a dedicated partition for our database
+ * @hd:		gendisk structure in which to create partition
+ * @dev:	device of which to create partition
+ * @ph:		@dev's LDM database private header
+ *
+ * Find the primary private header, locate the LDM database, then create a
+ * partition to wrap it.
+ *
+ * Return 1 on succes, 0 if device is not a dynamic disk and -1 on error.
+ */
+static int create_db_partition(struct gendisk *hd, const kdev_t dev,
+		const unsigned long first_sector, const int first_part_minor,
+		struct privhead *ph)
+{
+	struct buffer_head *bh;
+	int err;
+
+	if (!(bh = bread(dev, OFF_PRIVHEAD1, LDM_BLOCKSIZE))) {
+		printk(LDM_CRIT __FUNCTION__ "(): Device read failed.\n");
+		return -1;
+	}
+	if (BE64(bh->b_data) != MAGIC_PRIVHEAD) {
+		ldm_debug("Cannot find PRIVHEAD structure. Not a dynamic disk "
+				"or corrupt LDM database.\n");
+		return 0;
+	}
+	err = parse_privhead(bh->b_data, ph);
+	if (err == 1)
+		err = create_partition(hd, first_part_minor, first_sector +
+				ph->config_start, ph->config_size);
+	brelse(bh);
+	return err;
+}
+
+/**
+ * validate_patition_table - check whether @dev is a dynamic disk
+ * @dev:	device to test
+ *
+ * Check whether @dev is a dynamic disk by looking for an MS-DOS-style partition
+ * table with one or more entries of type 0x42 (the former Secure File System
+ * (Landis) partition type, now recycled by Microsoft for dynamic disks) in it.
+ * If this succeeds we assume we have a dynamic disk, and not otherwise.
+ *
+ * Return 1 if @dev is a dynamic disk, 0 if not and -1 on error.
+ */
+static int validate_partition_table(const kdev_t dev)
+{
+	struct buffer_head *bh;
+	struct partition *p;
+	int i, nr_sfs;
+
+	if (!(bh = bread(dev, 0, LDM_BLOCKSIZE))) {
+		if (warn_no_part)
+			printk(LDM_ERR "Unable to read partition table.\n");
+		return -1;
+	}
+	if (*(u16*)(bh->b_data + 0x01FE) != cpu_to_le16(MSDOS_LABEL_MAGIC)) {
+		ldm_debug("No MS-DOS partition found.\n");
+		goto no_msdos_partition;
+	}
+	nr_sfs = 0;
+	p = (struct partition*)(bh->b_data + 0x01BE);
+	for (i = 0; i < 4; i++) {
+		if (!SYS_IND(p+i) || SYS_IND(p+i) == WIN2K_EXTENDED_PARTITION)
+			continue;
+		if (SYS_IND(p+i) == WIN2K_DYNAMIC_PARTITION) {
+			nr_sfs++;
+			continue;
+		}
+		goto not_dynamic_disk;
+	}
+	if (!nr_sfs)
+		goto not_dynamic_disk;
+	ldm_debug("Parsed partition table successfully.\n");
+	brelse(bh);
+	return 1;
+not_dynamic_disk:
+	ldm_debug("Found basic MS-DOS partition, not a dynamic disk.\n");
+no_msdos_partition:
+	brelse(bh);
+	return 0;
+}
+
+/**
+ * ldm_partition - find out whether a device is a dynamic disk and handle it
+ * @hd:			gendisk structure in which to return the handled disk
+ * @dev:		device we need to look at
+ * @first_sector:	first sector within the device
+ * @first_part_minor:	first minor number of partitions for the device
+ *
+ * Description:
+ *
+ * This determines whether the device @dev is a dynamic disk and if so creates
+ * the partitions necessary in the gendisk structure pointed to by @hd.
+ *
+ * We create a dummy device 1, which contains the LDM database, we skip
+ * devices 2-4 and then create each partition described by the LDM database
+ * in sequence as devices 5 and following. For example, if the device is hda,
+ * we would have: hda1: LDM database, hda2-4: nothing, hda5-following: the
+ * actual data containing partitions.
+ *
+ * Return values:
+ *
+ *	 1 if @dev is a dynamic disk and we handled it,
+ *	 0 if @dev is not a dynamic disk,
+ *	-1 if an error occured.
+ */
+int ldm_partition(struct gendisk *hd, kdev_t dev, unsigned long first_sector,
+		int first_part_minor)
+{
+	kdev_t devdb;
+	struct privhead *ph  = NULL;
+	struct tocblock *toc = NULL;
+	struct vmdb     *vm  = NULL;
+	struct ldmdisk  *dk  = NULL;
+	int err;
+
+	if (!hd)
+		return 0;
+	err = (int)get_ptable_blocksize(dev);
+	if (err != LDM_BLOCKSIZE) {	/* 1024 bytes */
+		ldm_debug("Expected a blocksize of %d bytes, got %d instead.\n",
+				LDM_BLOCKSIZE, get_ptable_blocksize(dev));
+		return 0;
+	}
+	err = get_hardsect_size(dev); 
+	if (err != 512) {
+		ldm_debug("Expected a sector size of %d bytes, got %d "
+				"instead.\n", 512, get_hardsect_size(dev));
+		return 0;
+	}
+	/* Check the partition table. */
+	err = validate_partition_table(dev);
+	if (err != 1)
+		return err;
+	if (!(ph = (struct privhead*)kmalloc(sizeof(*ph), GFP_KERNEL)))
+		goto no_mem;
+	/* Create the LDM database device. */
+	err = create_db_partition(hd, dev, first_sector, first_part_minor, ph);
+	if (err != 1)
+		goto out;
+	/* For convenience, work with the LDM database device from now on. */
+	devdb = MKDEV(MAJOR(dev), first_part_minor);
+	/* Check the backup privheads. */
+	err = validate_privheads(devdb, ph);
+	if (err != 1)
+		goto out;
+	/* Check the table of contents and its backups. */
+	if (!(toc = (struct tocblock*)kmalloc(sizeof(*toc), GFP_KERNEL)))
+		goto no_mem;
+	err = validate_tocblocks(devdb, toc);
+	if (err != 1)
+		goto out;
+	/* Check the vmdb. */
+	if (!(vm = (struct vmdb*)kmalloc(sizeof(*vm), GFP_KERNEL)))
+		goto no_mem;
+	err = validate_vmdb(devdb, vm);
+	if (err != 1)
+		goto out;
+	/* Find the object id for @dev in the LDM database. */
+	if (!(dk = (struct ldmdisk*)kmalloc(sizeof(*dk), GFP_KERNEL)))
+		goto no_mem;
+	err = get_disk_objid(devdb, vm, ph, dk);
+	if (err != 1)
+		goto out;
+	/* Finally, create the data partition devices. */
+	err = create_data_partitions(hd, first_sector, first_part_minor +
+			LDM_FIRST_PART_OFFSET, devdb, vm, ph, dk);
+	if (err == 1)
+		ldm_debug("Parsed LDM database successfully.\n");
+out:
+	kfree(ph);
+	kfree(toc);
+	kfree(vm);
+	kfree(dk);
+	return err;
+no_mem:
+	printk(LDM_CRIT "Not enough memory to allocate required buffers.\n");
+	err = -1;
+	goto out;
+}
+
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)