xref: /src/sys/ufs/ext2fs/ext2fs_dir.h

/*	$NetBSD: ext2fs_dir.h,v 1.2 1998/09/13 15:14:40 christos Exp $	*/

/*
 * Copyright (c) 1997 Manuel Bouyer.
 * Copyright (c) 1982, 1986, 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)dir.h	8.4 (Berkeley) 8/10/94
 * Modified for ext2fs by Manuel Bouyer.
 */

#ifndef _EXT2FS_DIR_H_
#define	_EXT2FS_DIR_H_

/*
 * Theoretically, directories can be more than 2Gb in length, however, in
 * practice this seems unlikely. So, we define the type doff_t as a 32-bit
 * quantity to keep down the cost of doing lookup on a 32-bit machine.
 */
#define	doff_t		int32_t
#define	EXT2FS_MAXDIRSIZE	(0x7fffffff)

/*
 * A directory consists of some number of blocks of e2fs_bsize bytes.
 *
 * Each block contains some number of directory entry
 * structures, which are of variable length.  Each directory entry has
 * a struct direct at the front of it, containing its inode number,
 * the length of the entry, and the length of the name contained in
 * the entry.  These are followed by the name padded to a 4 byte boundary
 * with null bytes.  All names are guaranteed null terminated.
 * The maximum length of a name in a directory is EXT2FS_MAXNAMLEN.
 *
 * The macro EXT2FS_DIRSIZ(fmt, dp) gives the amount of space required to
 * represent a directory entry.  Free space in a directory is represented by
 * entries which have dp->e2d_reclen > DIRSIZ(fmt, dp).  All d2fs_bsize bytes
 * in a directory block are claimed by the directory entries.  This
 * usually results in the last entry in a directory having a large
 * dp->e2d_reclen.  When entries are deleted from a directory, the
 * space is returned to the previous entry in the same directory
 * block by increasing its dp->e2d_reclen.  If the first entry of
 * a directory block is free, then its dp->e2d_ino is set to 0.
 * Entries other than the first in a directory do not normally have
 * dp->e2d_ino set to 0.
 */

#define	EXT2FS_MAXNAMLEN	255

struct	ext2fs_direct {
	u_int32_t e2d_ino;		/* inode number of entry */
	u_int16_t e2d_reclen;		/* length of this record */
	u_int16_t e2d_namlen;		/* length of string in d_name */
	char	  e2d_name[EXT2FS_MAXNAMLEN];/* name with length <= EXT2FS_MAXNAMLEN */
};

/*
 * The EXT2FS_DIRSIZ macro gives the minimum record length which will hold
 * the directory entryfor a name len "len" (without the terminating null byte).
 * This requires the amount of space in struct direct
 * without the d_name field, plus enough space for the name without a
 * terminating null byte, rounded up to a 4 byte boundary.
 */
#define EXT2FS_DIRSIZ(len) \
   (( 8 + len + 3) &~ 3)

/*
 * Template for manipulating directories.  Should use struct direct's,
 * but the name field is EXT2FS_MAXNAMLEN - 1, and this just won't do.
 */
struct ext2fs_dirtemplate {
	u_int32_t	dot_ino;
	int16_t		dot_reclen;
	u_int16_t	dot_namlen;
	char		dot_name[4];	/* must be multiple of 4 */
	u_int32_t	dotdot_ino;
	int16_t		dotdot_reclen;
	u_int16_t	dotdot_namlen;
	char		dotdot_name[4];	/* ditto */
};

#endif /* !_EXT2FS_DIR_H_ */