sys/vfs/gnu/ext2fs/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. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)dir.h       8.2 (Berkeley) 1/21/94
  39  * $FreeBSD: src/sys/ufs/ufs/dir.h,v 1.9 1999/08/28 00:52:27 peter Exp $
  40  * $DragonFly: src/sys/vfs/gnu/ext2fs/dir.h,v 1.1 2006/04/04 17:34:32 dillon Exp $
  41  */
  42
  43 #ifndef _VFS_GNU_EXT2FS_DIR_H_
  44 #define _VFS_GNU_EXT2FS_DIR_H_
  45
  46 /*
  47  * Theoretically, directories can be more than 2Gb in length, however, in
  48  * practice this seems unlikely. So, we define the type doff_t as a 32-bit
  49  * quantity to keep down the cost of doing lookup on a 32-bit machine.
  50  */
  51 #define doff_t          int32_t
  52 #define MAXDIRSIZE      (0x7fffffff)
  53
  54 /*
  55  * A directory consists of some number of blocks of DIRBLKSIZ
  56  * bytes, where DIRBLKSIZ is chosen such that it can be transferred
  57  * to disk in a single atomic operation (e.g. 512 bytes on most machines).
  58  *
  59  * Each DIRBLKSIZ byte block contains some number of directory entry
  60  * structures, which are of variable length.  Each directory entry has
  61  * a struct direct at the front of it, containing its inode number,
  62  * the length of the entry, and the length of the name contained in
  63  * the entry.  These are followed by the name padded to a 4 byte boundary
  64  * with null bytes.  All names are guaranteed null terminated.
  65  * The maximum length of a name in a directory is MAXNAMLEN.
  66  *
  67  * The macro DIRSIZ(fmt, dp) gives the amount of space required to represent
  68  * a directory entry.  Free space in a directory is represented by
  69  * entries which have dp->d_reclen > DIRSIZ(fmt, dp).  All DIRBLKSIZ bytes
  70  * in a directory block are claimed by the directory entries.  This
  71  * usually results in the last entry in a directory having a large
  72  * dp->d_reclen.  When entries are deleted from a directory, the
  73  * space is returned to the previous entry in the same directory
  74  * block by increasing its dp->d_reclen.  If the first entry of
  75  * a directory block is free, then its dp->d_ino is set to 0.
  76  * Entries other than the first in a directory do not normally have
  77  * dp->d_ino set to 0.
  78  */
  79 #define DIRBLKSIZ       DEV_BSIZE
  80 #define MAXNAMLEN       255
  81
  82 struct  direct {
  83         uint32_t d_ino;         /* inode number of entry */
  84         uint16_t d_reclen;              /* length of this record */
  85         uint8_t  d_type;                /* file type, see below */
  86         uint8_t  d_namlen;              /* length of string in d_name */
  87         char      d_name[MAXNAMLEN + 1];/* name with length <= MAXNAMLEN */
  88 };
  89
  90 /*
  91  * File types
  92  */
  93 #define DT_UNKNOWN       0
  94 #define DT_FIFO          1
  95 #define DT_CHR           2
  96 #define DT_DIR           4
  97 #define DT_BLK           6
  98 #define DT_REG           8
  99 #define DT_LNK          10
 100 #define DT_SOCK         12
 101 #define DT_WHT          14
 102
 103 /*
 104  * Convert between stat structure types and directory types.
 105  */
 106 #define IFTODT(mode)    (((mode) & 0170000) >> 12)
 107 #define DTTOIF(dirtype) ((dirtype) << 12)
 108
 109 /*
 110  * The DIRSIZ macro gives the minimum record length which will hold
 111  * the directory entry.  This requires the amount of space in struct direct
 112  * without the d_name field, plus enough space for the name with a terminating
 113  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
 114  *
 115  *
 116  */
 117 #define DIRECTSIZ(namlen)                                               \
 118         (((int)&((struct direct *)0)->d_name +                          \
 119           ((namlen)+1)*sizeof(((struct direct *)0)->d_name[0]) + 3) & ~3)
 120 #if (BYTE_ORDER == LITTLE_ENDIAN)
 121 #define DIRSIZ(oldfmt, dp) \
 122     ((oldfmt) ? DIRECTSIZ((dp)->d_type) : DIRECTSIZ((dp)->d_namlen))
 123 #else
 124 #define DIRSIZ(oldfmt, dp) \
 125     DIRECTSIZ((dp)->d_namlen)
 126 #endif
 127 #define OLDDIRFMT       1
 128 #define NEWDIRFMT       0
 129
 130 /*
 131  * Template for manipulating directories.  Should use struct direct's,
 132  * but the name field is MAXNAMLEN - 1, and this just won't do.
 133  */
 134 struct dirtemplate {
 135         uint32_t        dot_ino;
 136         int16_t         dot_reclen;
 137         uint8_t dot_type;
 138         uint8_t dot_namlen;
 139         char            dot_name[4];    /* must be multiple of 4 */
 140         uint32_t        dotdot_ino;
 141         int16_t         dotdot_reclen;
 142         uint8_t dotdot_type;
 143         uint8_t dotdot_namlen;
 144         char            dotdot_name[4]; /* ditto */
 145 };
 146
 147 /*
 148  * This is the old format of directories, sanz type element.
 149  */
 150 struct odirtemplate {
 151         uint32_t        dot_ino;
 152         int16_t         dot_reclen;
 153         uint16_t        dot_namlen;
 154         char            dot_name[4];    /* must be multiple of 4 */
 155         uint32_t        dotdot_ino;
 156         int16_t         dotdot_reclen;
 157         uint16_t        dotdot_namlen;
 158         char            dotdot_name[4]; /* ditto */
 159 };
 160 #endif /* _VFS_GNU_EXT2FS_DIR_H_ */