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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License, Version 1.0 only
      6  * (the "License").  You may not use this file except in compliance
      7  * with the License.
      8  *
      9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
     10  * or http://www.opensolaris.org/os/licensing.
     11  * See the License for the specific language governing permissions
     12  * and limitations under the License.
     13  *
     14  * When distributing Covered Code, include this CDDL HEADER in each
     15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     16  * If applicable, add the following below this CDDL HEADER, with the
     17  * fields enclosed by brackets "[]" replaced with your own identifying
     18  * information: Portions Copyright [yyyy] [name of copyright owner]
     19  *
     20  * CDDL HEADER END
     21  */
     22 /*
     23  * Copyright 1998 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
     28 /*	  All Rights Reserved  	*/
     29 
     30 /*
     31  * University Copyright- Copyright (c) 1982, 1986, 1988
     32  * The Regents of the University of California
     33  * All Rights Reserved
     34  *
     35  * University Acknowledgment- Portions of this document are derived from
     36  * software developed by the University of California, Berkeley, and its
     37  * contributors.
     38  */
     39 
     40 #ifndef	_SYS_FS_UFS_FSDIR_H
     41 #define	_SYS_FS_UFS_FSDIR_H
     42 
     43 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     44 
     45 #ifdef	__cplusplus
     46 extern "C" {
     47 #endif
     48 
     49 /*
     50  * A directory consists of some number of blocks of DIRBLKSIZ
     51  * bytes, where DIRBLKSIZ is chosen such that it can be transferred
     52  * to disk in a single atomic operation (e.g. 512 bytes on most machines).
     53  *
     54  * Each DIRBLKSIZ byte block contains some number of directory entry
     55  * structures, which are of variable length.  Each directory entry has
     56  * a struct direct at the front of it, containing its inode number,
     57  * the length of the entry, and the length of the name contained in
     58  * the entry.  These are followed by the name padded to a 4 byte boundary
     59  * with null bytes.  All names are guaranteed null terminated.
     60  * The maximum length of a name in a directory is MAXNAMLEN.
     61  *
     62  * The macro DIRSIZ(dp) gives the amount of space required to represent
     63  * a directory entry.  Free space in a directory is represented by
     64  * entries which have dp->d_reclen > DIRSIZ(dp).  All DIRBLKSIZ bytes
     65  * in a directory block are claimed by the directory entries.  This
     66  * usually results in the last entry in a directory having a large
     67  * dp->d_reclen.  When entries are deleted from a directory, the
     68  * space is returned to the previous entry in the same directory
     69  * block by increasing its dp->d_reclen.  If the first entry of
     70  * a directory block is free, then its dp->d_ino is set to 0.
     71  * Entries other than the first in a directory do not normally have
     72  * dp->d_ino set to 0.
     73  */
     74 #define	DIRBLKSIZ	DEV_BSIZE
     75 #define	MAXNAMLEN	255
     76 
     77 struct	direct {
     78 	uint32_t	d_ino;		/* inode number of entry */
     79 	ushort_t	d_reclen;	/* length of this record */
     80 	ushort_t	d_namlen;	/* length of string in d_name */
     81 	char	d_name[MAXNAMLEN + 1];	/* name must be no longer than this */
     82 };
     83 
     84 /*
     85  * The DIRSIZ macro gives the minimum record length which will hold
     86  * the directory entry.  This requires the amount of space in struct direct
     87  * without the d_name field, plus enough space for the name with a terminating
     88  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
     89  */
     90 #undef DIRSIZ
     91 #define	DIRSIZ(dp) \
     92 	((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1+3) &~ 3))
     93 
     94 #ifdef _KERNEL
     95 /*
     96  * Template for manipulating directories.
     97  * Should use struct direct's, but the name field
     98  * is MAXNAMLEN - 1, and this just won't do.
     99  */
    100 struct dirtemplate {
    101 	uint32_t	dot_ino;
    102 	short		dot_reclen;
    103 	short		dot_namlen;
    104 	char		dot_name[4];		/* must be multiple of 4 */
    105 	uint32_t	dotdot_ino;
    106 	short		dotdot_reclen;
    107 	short		dotdot_namlen;
    108 	char		dotdot_name[4];		/* ditto */
    109 };
    110 #endif
    111 
    112 #ifdef	__cplusplus
    113 }
    114 #endif
    115 
    116 #endif	/* _SYS_FS_UFS_FSDIR_H */
    117