ldm.c

linux 内核源代码

	if (len > BE32(buffer + 0x14)) {
		ldm_error("len %d > BE32(buffer + 0x14) %d", len,
				BE32(buffer + 0x14));
		return false;
	}
	part = &vb->vblk.part;
	part->start = BE64(buffer + 0x24 + r_name);
	part->volume_offset = BE64(buffer + 0x2C + r_name);
	part->size = ldm_get_vnum(buffer + 0x34 + r_name);
	part->parent_id = ldm_get_vnum(buffer + 0x34 + r_size);
	part->disk_id = ldm_get_vnum(buffer + 0x34 + r_parent);
	if (vb->flags & VBLK_FLAG_PART_INDEX)
		part->partnum = buffer[0x35 + r_diskid];
	else
		part->partnum = 0;
	return true;
}

/**
 * ldm_parse_vol5 - Read a raw VBLK Volume object into a vblk structure
 * @buffer:  Block of data being worked on
 * @buflen:  Size of the block of data
 * @vb:      In-memory vblk in which to return information
 *
 * Read a raw VBLK Volume object (version 5) into a vblk structure.
 *
 * Return:  'true'   @vb contains a Volume VBLK
 *          'false'  @vb contents are not defined
 */
static bool ldm_parse_vol5(const u8 *buffer, int buflen, struct vblk *vb)
{
	int r_objid, r_name, r_vtype, r_disable_drive_letter, r_child, r_size;
	int r_id1, r_id2, r_size2, r_drive, len;
	struct vblk_volu *volu;

	BUG_ON(!buffer || !vb);
	r_objid = ldm_relative(buffer, buflen, 0x18, 0);
	if (r_objid < 0) {
		ldm_error("r_objid %d < 0", r_objid);
		return false;
	}
	r_name = ldm_relative(buffer, buflen, 0x18, r_objid);
	if (r_name < 0) {
		ldm_error("r_name %d < 0", r_name);
		return false;
	}
	r_vtype = ldm_relative(buffer, buflen, 0x18, r_name);
	if (r_vtype < 0) {
		ldm_error("r_vtype %d < 0", r_vtype);
		return false;
	}
	r_disable_drive_letter = ldm_relative(buffer, buflen, 0x18, r_vtype);
	if (r_disable_drive_letter < 0) {
		ldm_error("r_disable_drive_letter %d < 0",
				r_disable_drive_letter);
		return false;
	}
	r_child = ldm_relative(buffer, buflen, 0x2D, r_disable_drive_letter);
	if (r_child < 0) {
		ldm_error("r_child %d < 0", r_child);
		return false;
	}
	r_size = ldm_relative(buffer, buflen, 0x3D, r_child);
	if (r_size < 0) {
		ldm_error("r_size %d < 0", r_size);
		return false;
	}
	if (buffer[0x12] & VBLK_FLAG_VOLU_ID1) {
		r_id1 = ldm_relative(buffer, buflen, 0x52, r_size);
		if (r_id1 < 0) {
			ldm_error("r_id1 %d < 0", r_id1);
			return false;
		}
	} else
		r_id1 = r_size;
	if (buffer[0x12] & VBLK_FLAG_VOLU_ID2) {
		r_id2 = ldm_relative(buffer, buflen, 0x52, r_id1);
		if (r_id2 < 0) {
			ldm_error("r_id2 %d < 0", r_id2);
			return false;
		}
	} else
		r_id2 = r_id1;
	if (buffer[0x12] & VBLK_FLAG_VOLU_SIZE) {
		r_size2 = ldm_relative(buffer, buflen, 0x52, r_id2);
		if (r_size2 < 0) {
			ldm_error("r_size2 %d < 0", r_size2);
			return false;
		}
	} else
		r_size2 = r_id2;
	if (buffer[0x12] & VBLK_FLAG_VOLU_DRIVE) {
		r_drive = ldm_relative(buffer, buflen, 0x52, r_size2);
		if (r_drive < 0) {
			ldm_error("r_drive %d < 0", r_drive);
			return false;
		}
	} else
		r_drive = r_size2;
	len = r_drive;
	if (len < 0) {
		ldm_error("len %d < 0", len);
		return false;
	}
	len += VBLK_SIZE_VOL5;
	if (len > BE32(buffer + 0x14)) {
		ldm_error("len %d > BE32(buffer + 0x14) %d", len,
				BE32(buffer + 0x14));
		return false;
	}
	volu = &vb->vblk.volu;
	ldm_get_vstr(buffer + 0x18 + r_name, volu->volume_type,
			sizeof(volu->volume_type));
	memcpy(volu->volume_state, buffer + 0x18 + r_disable_drive_letter,
			sizeof(volu->volume_state));
	volu->size = ldm_get_vnum(buffer + 0x3D + r_child);
	volu->partition_type = buffer[0x41 + r_size];
	memcpy(volu->guid, buffer + 0x42 + r_size, sizeof(volu->guid));
	if (buffer[0x12] & VBLK_FLAG_VOLU_DRIVE) {
		ldm_get_vstr(buffer + 0x52 + r_size, volu->drive_hint,
				sizeof(volu->drive_hint));
	}
	return true;
}

/**
 * ldm_parse_vblk - Read a raw VBLK object into a vblk structure
 * @buf:  Block of data being worked on
 * @len:  Size of the block of data
 * @vb:   In-memory vblk in which to return information
 *
 * Read a raw VBLK object into a vblk structure.  This function just reads the
 * information common to all VBLK types, then delegates the rest of the work to
 * helper functions: ldm_parse_*.
 *
 * Return:  'true'   @vb contains a VBLK
 *          'false'  @vb contents are not defined
 */
static bool ldm_parse_vblk (const u8 *buf, int len, struct vblk *vb)
{
	bool result = false;
	int r_objid;

	BUG_ON (!buf || !vb);

	r_objid = ldm_relative (buf, len, 0x18, 0);
	if (r_objid < 0) {
		ldm_error ("VBLK header is corrupt.");
		return false;
	}

	vb->flags  = buf[0x12];
	vb->type   = buf[0x13];
	vb->obj_id = ldm_get_vnum (buf + 0x18);
	ldm_get_vstr (buf+0x18+r_objid, vb->name, sizeof (vb->name));

	switch (vb->type) {
		case VBLK_CMP3:  result = ldm_parse_cmp3 (buf, len, vb); break;
		case VBLK_DSK3:  result = ldm_parse_dsk3 (buf, len, vb); break;
		case VBLK_DSK4:  result = ldm_parse_dsk4 (buf, len, vb); break;
		case VBLK_DGR3:  result = ldm_parse_dgr3 (buf, len, vb); break;
		case VBLK_DGR4:  result = ldm_parse_dgr4 (buf, len, vb); break;
		case VBLK_PRT3:  result = ldm_parse_prt3 (buf, len, vb); break;
		case VBLK_VOL5:  result = ldm_parse_vol5 (buf, len, vb); break;
	}

	if (result)
		ldm_debug ("Parsed VBLK 0x%llx (type: 0x%02x) ok.",
			 (unsigned long long) vb->obj_id, vb->type);
	else
		ldm_error ("Failed to parse VBLK 0x%llx (type: 0x%02x).",
			(unsigned long long) vb->obj_id, vb->type);

	return result;
}


/**
 * ldm_ldmdb_add - Adds a raw VBLK entry to the ldmdb database
 * @data:  Raw VBLK to add to the database
 * @len:   Size of the raw VBLK
 * @ldb:   Cache of the database structures
 *
 * The VBLKs are sorted into categories.  Partitions are also sorted by offset.
 *
 * N.B.  This function does not check the validity of the VBLKs.
 *
 * Return:  'true'   The VBLK was added
 *          'false'  An error occurred
 */
static bool ldm_ldmdb_add (u8 *data, int len, struct ldmdb *ldb)
{
	struct vblk *vb;
	struct list_head *item;

	BUG_ON (!data || !ldb);

	vb = kmalloc (sizeof (*vb), GFP_KERNEL);
	if (!vb) {
		ldm_crit ("Out of memory.");
		return false;
	}

	if (!ldm_parse_vblk (data, len, vb)) {
		kfree(vb);
		return false;			/* Already logged */
	}

	/* Put vblk into the correct list. */
	switch (vb->type) {
	case VBLK_DGR3:
	case VBLK_DGR4:
		list_add (&vb->list, &ldb->v_dgrp);
		break;
	case VBLK_DSK3:
	case VBLK_DSK4:
		list_add (&vb->list, &ldb->v_disk);
		break;
	case VBLK_VOL5:
		list_add (&vb->list, &ldb->v_volu);
		break;
	case VBLK_CMP3:
		list_add (&vb->list, &ldb->v_comp);
		break;
	case VBLK_PRT3:
		/* Sort by the partition's start sector. */
		list_for_each (item, &ldb->v_part) {
			struct vblk *v = list_entry (item, struct vblk, list);
			if ((v->vblk.part.disk_id == vb->vblk.part.disk_id) &&
			    (v->vblk.part.start > vb->vblk.part.start)) {
				list_add_tail (&vb->list, &v->list);
				return true;
			}
		}
		list_add_tail (&vb->list, &ldb->v_part);
		break;
	}
	return true;
}

/**
 * ldm_frag_add - Add a VBLK fragment to a list
 * @data:   Raw fragment to be added to the list
 * @size:   Size of the raw fragment
 * @frags:  Linked list of VBLK fragments
 *
 * Fragmented VBLKs may not be consecutive in the database, so they are placed
 * in a list so they can be pieced together later.
 *
 * Return:  'true'   Success, the VBLK was added to the list
 *          'false'  Error, a problem occurred
 */
static bool ldm_frag_add (const u8 *data, int size, struct list_head *frags)
{
	struct frag *f;
	struct list_head *item;
	int rec, num, group;

	BUG_ON (!data || !frags);

	group = BE32 (data + 0x08);
	rec   = BE16 (data + 0x0C);
	num   = BE16 (data + 0x0E);
	if ((num < 1) || (num > 4)) {
		ldm_error ("A VBLK claims to have %d parts.", num);
		return false;
	}

	list_for_each (item, frags) {
		f = list_entry (item, struct frag, list);
		if (f->group == group)
			goto found;
	}

	f = kmalloc (sizeof (*f) + size*num, GFP_KERNEL);
	if (!f) {
		ldm_crit ("Out of memory.");
		return false;
	}

	f->group = group;
	f->num   = num;
	f->rec   = rec;
	f->map   = 0xFF << num;

	list_add_tail (&f->list, frags);
found:
	if (f->map & (1 << rec)) {
		ldm_error ("Duplicate VBLK, part %d.", rec);
		f->map &= 0x7F;			/* Mark the group as broken */
		return false;
	}

	f->map |= (1 << rec);

	if (num > 0) {
		data += VBLK_SIZE_HEAD;
		size -= VBLK_SIZE_HEAD;
	}
	memcpy (f->data+rec*(size-VBLK_SIZE_HEAD)+VBLK_SIZE_HEAD, data, size);

	return true;
}

/**
 * ldm_frag_free - Free a linked list of VBLK fragments
 * @list:  Linked list of fragments
 *
 * Free a linked list of VBLK fragments
 *
 * Return:  none
 */
static void ldm_frag_free (struct list_head *list)
{
	struct list_head *item, *tmp;

	BUG_ON (!list);

	list_for_each_safe (item, tmp, list)
		kfree (list_entry (item, struct frag, list));
}

/**
 * ldm_frag_commit - Validate fragmented VBLKs and add them to the database
 * @frags:  Linked list of VBLK fragments
 * @ldb:    Cache of the database structures
 *
 * Now that all the fragmented VBLKs have been collected, they must be added to
 * the database for later use.
 *
 * Return:  'true'   All the fragments we added successfully
 *          'false'  One or more of the fragments we invalid
 */
static bool ldm_frag_commit (struct list_head *frags, struct ldmdb *ldb)
{
	struct frag *f;
	struct list_head *item;

	BUG_ON (!frags || !ldb);

	list_for_each (item, frags) {
		f = list_entry (item, struct frag, list);

		if (f->map != 0xFF) {
			ldm_error ("VBLK group %d is incomplete (0x%02x).",
				f->group, f->map);
			return false;
		}

		if (!ldm_ldmdb_add (f->data, f->num*ldb->vm.vblk_size, ldb))
			return false;		/* Already logged */
	}
	return true;
}

/**
 * ldm_get_vblks - Read the on-disk database of VBLKs into memory
 * @bdev:  Device holding the LDM Database
 * @base:  Offset, into @bdev, of the database
 * @ldb:   Cache of the database structures
 *
 * To use the information from the VBLKs, they need to be read from the disk,
 * unpacked and validated.  We cache them in @ldb according to their type.
 *
 * Return:  'true'   All the VBLKs were read successfully
 *          'false'  An error occurred
 */
static bool ldm_get_vblks (struct block_device *bdev, unsigned long base,
			   struct ldmdb *ldb)
{
	int size, perbuf, skip, finish, s, v, recs;
	u8 *data = NULL;
	Sector sect;
	bool result = false;
	LIST_HEAD (frags);

	BUG_ON (!bdev || !ldb);

	size   = ldb->vm.vblk_size;
	perbuf = 512 / size;
	skip   = ldb->vm.vblk_offset >> 9;		/* Bytes to sectors */
	finish = (size * ldb->vm.last_vblk_seq) >> 9;

	for (s = skip; s < finish; s++) {		/* For each sector */
		data = read_dev_sector (bdev, base + OFF_VMDB + s, &sect);
		if (!data) {
			ldm_crit ("Disk read failed.");
			goto out;
		}

		for (v = 0; v < perbuf; v++, data+=size) {  /* For each vblk */
			if (MAGIC_VBLK != BE32 (data)) {
				ldm_error ("Expected to find a VBLK.");
				goto out;
			}

			recs = BE16 (data + 0x0E);	/* Number of records */
			if (recs == 1) {
				if (!ldm_ldmdb_add (data, size, ldb))
					goto out;	/* Already logged */
			} else if (recs > 1) {
				if (!ldm_frag_add (data, size, &frags))
					goto out;	/* Already logged */
			}
			/* else Record is not in use, ignore it. */
		}
		put_dev_sector (sect);
		data = NULL;
	}

	result = ldm_frag_commit (&frags, ldb);	/* Failures, already logged */
out:
	if (data)
		put_dev_sector (sect);
	ldm_frag_free (&frags);

	return result;
}

/**
 * ldm_free_vblks - Free a linked list of vblk's
 * @lh:  Head of a linked list of struct vblk
 *
 * Free a list of vblk's and free the memory used to maintain the list.
 *
 * Return:  none
 */
static void ldm_free_vblks (struct list_head *lh)
{
	struct list_head *item, *tmp;

	BUG_ON (!lh);

	list_for_each_safe (item, tmp, lh)
		kfree (list_entry (item, struct vblk, list));
}


/**
 * ldm_partition - Find out whether a device is a dynamic disk and handle it
 * @pp:    List of the partitions parsed so far
 * @bdev:  Device holding the LDM Database
 *
 * This determines whether the device @bdev 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, and then create
 * each partition described by the LDM database in sequence as devices 2+. For
 * example, if the device is hda, we would have: hda1: LDM database, hda2, hda3,
 * and so on: the actual data containing partitions.
 *
 * Return:  1 Success, @bdev is a dynamic disk and we handled it
 *          0 Success, @bdev is not a dynamic disk
 *         -1 An error occurred before enough information had been read
 *            Or @bdev is a dynamic disk, but it may be corrupted
 */
int ldm_partition (struct parsed_partitions *pp, struct block_device *bdev)
{
	struct ldmdb  *ldb;
	unsigned long base;
	int result = -1;

	BUG_ON (!pp || !bdev);

	/* Look for signs of a Dynamic Disk */
	if (!ldm_validate_partition_table (bdev))
		return 0;

	ldb = kmalloc (sizeof (*ldb), GFP_KERNEL);
	if (!ldb) {
		ldm_crit ("Out of memory.");
		goto out;
	}

	/* Parse and check privheads. */
	if (!ldm_validate_privheads (bdev, &ldb->ph))
		goto out;		/* Already logged */

	/* All further references are relative to base (database start). */
	base = ldb->ph.config_start;

	/* Parse and check tocs and vmdb. */
	if (!ldm_validate_tocblocks (bdev, base, ldb) ||
	    !ldm_validate_vmdb      (bdev, base, ldb))
	    	goto out;		/* Already logged */

	/* Initialize vblk lists in ldmdb struct */
	INIT_LIST_HEAD (&ldb->v_dgrp);
	INIT_LIST_HEAD (&ldb->v_disk);
	INIT_LIST_HEAD (&ldb->v_volu);
	INIT_LIST_HEAD (&ldb->v_comp);
	INIT_LIST_HEAD (&ldb->v_part);

	if (!ldm_get_vblks (bdev, base, ldb)) {
		ldm_crit ("Failed to read the VBLKs from the database.");
		goto cleanup;
	}

	/* Finally, create the data partition devices. */
	if (ldm_create_data_partitions (pp, ldb)) {
		ldm_debug ("Parsed LDM database successfully.");
		result = 1;
	}
	/* else Already logged */

cleanup:
	ldm_free_vblks (&ldb->v_dgrp);
	ldm_free_vblks (&ldb->v_disk);
	ldm_free_vblks (&ldb->v_volu);
	ldm_free_vblks (&ldb->v_comp);
	ldm_free_vblks (&ldb->v_part);
out:
	kfree (ldb);
	return result;
}