include/sys/fs/ufs_fsdir.h

   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 #ifdef  __cplusplus
  44 extern "C" {
  45 #endif
  46
  47 /*
  48  * A directory consists of some number of blocks of DIRBLKSIZ
  49  * bytes, where DIRBLKSIZ is chosen such that it can be transferred
  50  * to disk in a single atomic operation (e.g. 512 bytes on most machines).
  51  *
  52  * Each DIRBLKSIZ byte block contains some number of directory entry
  53  * structures, which are of variable length.  Each directory entry has
  54  * a struct direct at the front of it, containing its inode number,
  55  * the length of the entry, and the length of the name contained in
  56  * the entry.  These are followed by the name padded to a 4 byte boundary
  57  * with null bytes.  All names are guaranteed null terminated.
  58  * The maximum length of a name in a directory is MAXNAMLEN.
  59  *
  60  * The macro DIRSIZ(dp) gives the amount of space required to represent
  61  * a directory entry.  Free space in a directory is represented by
  62  * entries which have dp->d_reclen > DIRSIZ(dp).  All DIRBLKSIZ bytes
  63  * in a directory block are claimed by the directory entries.  This
  64  * usually results in the last entry in a directory having a large
  65  * dp->d_reclen.  When entries are deleted from a directory, the
  66  * space is returned to the previous entry in the same directory
  67  * block by increasing its dp->d_reclen.  If the first entry of
  68  * a directory block is free, then its dp->d_ino is set to 0.
  69  * Entries other than the first in a directory do not normally have
  70  * dp->d_ino set to 0.
  71  */
  72 #define DIRBLKSIZ       DEV_BSIZE
  73 #define MAXNAMLEN       255
  74
  75 struct  direct {
  76         uint32_t        d_ino;          /* inode number of entry */
  77         ushort_t        d_reclen;       /* length of this record */
  78         ushort_t        d_namlen;       /* length of string in d_name */
  79         char    d_name[MAXNAMLEN + 1];  /* name must be no longer than this */
  80 };
  81
  82 /*
  83  * The DIRSIZ macro gives the minimum record length which will hold
  84  * the directory entry.  This requires the amount of space in struct direct
  85  * without the d_name field, plus enough space for the name with a terminating
  86  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
  87  */
  88 #undef DIRSIZ
  89 #define DIRSIZ(dp) \
  90         ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1+3) &~ 3))
  91
  92 #ifdef _KERNEL
  93 /*
  94  * Template for manipulating directories.
  95  * Should use struct direct's, but the name field
  96  * is MAXNAMLEN - 1, and this just won't do.
  97  */
  98 struct dirtemplate {
  99         uint32_t        dot_ino;
 100         short           dot_reclen;
 101         short           dot_namlen;
 102         char            dot_name[4];            /* must be multiple of 4 */
 103         uint32_t        dotdot_ino;
 104         short           dotdot_reclen;
 105         short           dotdot_namlen;
 106         char            dotdot_name[4];         /* ditto */
 107 };
 108 #endif
 109
 110 #ifdef  __cplusplus
 111 }
 112 #endif
 113
 114 #endif  /* _SYS_FS_UFS_FSDIR_H */