sys/vfs/ufs/dir.h

   1 /*-
   2  * Copyright (c) 1982, 1986, 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * (c) UNIX System Laboratories, Inc.
   5  * All or some portions of this file are derived from material licensed
   6  * to the University of California by American Telephone and Telegraph
   7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   8  * the permission of UNIX System Laboratories, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)dir.h       8.2 (Berkeley) 1/21/94
  35  * $FreeBSD: src/sys/ufs/ufs/dir.h,v 1.9 1999/08/28 00:52:27 peter Exp $
  36  * $DragonFly: src/sys/vfs/ufs/dir.h,v 1.4 2006/04/03 02:02:37 dillon Exp $
  37  */
  38
  39 #ifndef _VFS_UFS_DIR_H_
  40 #define _VFS_UFS_DIR_H_
  41
  42 /*
  43  * Theoretically, directories can be more than 2Gb in length, however, in
  44  * practice this seems unlikely. So, we define the type doff_t as a 32-bit
  45  * quantity to keep down the cost of doing lookup on a 32-bit machine.
  46  */
  47 #define doff_t          int32_t
  48 #define MAXDIRSIZE      (0x7fffffff)
  49
  50 /*
  51  * A directory consists of some number of blocks of DIRBLKSIZ
  52  * bytes, where DIRBLKSIZ is chosen such that it can be transferred
  53  * to disk in a single atomic operation (e.g. 512 bytes on most machines).
  54  *
  55  * Each DIRBLKSIZ byte block contains some number of directory entry
  56  * structures, which are of variable length.  Each directory entry has
  57  * a struct direct at the front of it, containing its inode number,
  58  * the length of the entry, and the length of the name contained in
  59  * the entry.  These are followed by the name padded to a 4 byte boundary
  60  * with null bytes.  All names are guaranteed null terminated.
  61  * The maximum length of a name in a directory is MAXNAMLEN.
  62  *
  63  * The macro DIRSIZ(fmt, dp) gives the amount of space required to represent
  64  * a directory entry.  Free space in a directory is represented by
  65  * entries which have dp->d_reclen > DIRSIZ(fmt, dp).  All DIRBLKSIZ bytes
  66  * in a directory block are claimed by the directory entries.  This
  67  * usually results in the last entry in a directory having a large
  68  * dp->d_reclen.  When entries are deleted from a directory, the
  69  * space is returned to the previous entry in the same directory
  70  * block by increasing its dp->d_reclen.  If the first entry of
  71  * a directory block is free, then its dp->d_ino is set to 0.
  72  * Entries other than the first in a directory do not normally have
  73  * dp->d_ino set to 0.
  74  */
  75 #define DIRBLKSIZ       DEV_BSIZE
  76 #define MAXNAMLEN       255
  77
  78 struct  direct {
  79         uint32_t d_ino;         /* inode number of entry */
  80         uint16_t d_reclen;              /* length of this record */
  81         uint8_t  d_type;                /* file type, see below */
  82         uint8_t  d_namlen;              /* length of string in d_name */
  83         char      d_name[MAXNAMLEN + 1];/* name with length <= MAXNAMLEN */
  84 };
  85
  86 /*
  87  * File types
  88  */
  89 #define DT_UNKNOWN       0
  90 #define DT_FIFO          1
  91 #define DT_CHR           2
  92 #define DT_DIR           4
  93 #define DT_BLK           6
  94 #define DT_REG           8
  95 #define DT_LNK          10
  96 #define DT_SOCK         12
  97 #define DT_WHT          14
  98
  99 /*
 100  * Convert between stat structure types and directory types.
 101  */
 102 #define IFTODT(mode)    (((mode) & 0170000) >> 12)
 103 #define DTTOIF(dirtype) ((dirtype) << 12)
 104
 105 /*
 106  * The DIRSIZ macro gives the minimum record length which will hold
 107  * the directory entry.  This requires the amount of space in struct direct
 108  * without the d_name field, plus enough space for the name with a terminating
 109  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
 110  *
 111  *
 112  */
 113 #define DIRECTSIZ(namlen)                                               \
 114         ((__offsetof(struct direct, d_name) +                           \
 115           ((namlen)+1)*sizeof(((struct direct *)0)->d_name[0]) + 3) & ~3)
 116 #if (BYTE_ORDER == LITTLE_ENDIAN)
 117 #define DIRSIZ(oldfmt, dp) \
 118     ((oldfmt) ? DIRECTSIZ((dp)->d_type) : DIRECTSIZ((dp)->d_namlen))
 119 #else
 120 #define DIRSIZ(oldfmt, dp) \
 121     DIRECTSIZ((dp)->d_namlen)
 122 #endif
 123 #define OLDDIRFMT       1
 124 #define NEWDIRFMT       0
 125
 126 /*
 127  * Template for manipulating directories.  Should use struct direct's,
 128  * but the name field is MAXNAMLEN - 1, and this just won't do.
 129  */
 130 struct dirtemplate {
 131         uint32_t        dot_ino;
 132         int16_t         dot_reclen;
 133         uint8_t dot_type;
 134         uint8_t dot_namlen;
 135         char            dot_name[4];    /* must be multiple of 4 */
 136         uint32_t        dotdot_ino;
 137         int16_t         dotdot_reclen;
 138         uint8_t dotdot_type;
 139         uint8_t dotdot_namlen;
 140         char            dotdot_name[4]; /* ditto */
 141 };
 142
 143 /*
 144  * This is the old format of directories, sanz type element.
 145  */
 146 struct odirtemplate {
 147         uint32_t        dot_ino;
 148         int16_t         dot_reclen;
 149         uint16_t        dot_namlen;
 150         char            dot_name[4];    /* must be multiple of 4 */
 151         uint32_t        dotdot_ino;
 152         int16_t         dotdot_reclen;
 153         uint16_t        dotdot_namlen;
 154         char            dotdot_name[4]; /* ditto */
 155 };
 156 #endif /* !_VFS_UFS_DIR_H_ */