dir.h revision 262779 
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 * 4. 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: stable/10/sys/ufs/ufs/dir.h 262779 2014-03-05 04:23:19Z pfg $
36 */
37
38#ifndef _UFS_UFS_DIR_H_
39#define	_UFS_UFS_DIR_H_
40
41/*
42 * Theoretically, directories can be more than 2Gb in length, however, in
43 * practice this seems unlikely. So, we define the type doff_t as a 32-bit
44 * quantity to keep down the cost of doing lookup on a 32-bit machine.
45 */
46#define	doff_t		int32_t
47#define	MAXDIRSIZE	(0x7fffffff)
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(fmt, 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(fmt, 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
77struct	direct {
78	u_int32_t d_ino;		/* inode number of entry */
79	u_int16_t d_reclen;		/* length of this record */
80	u_int8_t  d_type; 		/* file type, see below */
81	u_int8_t  d_namlen;		/* length of string in d_name */
82	char	  d_name[MAXNAMLEN + 1];/* name with length <= MAXNAMLEN */
83};
84
85/*
86 * File types
87 */
88#define	DT_UNKNOWN	 0
89#define	DT_FIFO		 1
90#define	DT_CHR		 2
91#define	DT_DIR		 4
92#define	DT_BLK		 6
93#define	DT_REG		 8
94#define	DT_LNK		10
95#define	DT_SOCK		12
96#define	DT_WHT		14
97
98/*
99 * Convert between stat structure types and directory types.
100 */
101#define	IFTODT(mode)	(((mode) & 0170000) >> 12)
102#define	DTTOIF(dirtype)	((dirtype) << 12)
103
104/*
105 * The DIRSIZ macro gives the minimum record length which will hold
106 * the directory entry.  This requires the amount of space in struct direct
107 * without the d_name field, plus enough space for the name with a terminating
108 * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
109 *
110 *
111 */
112#define	DIRECTSIZ(namlen)						\
113	(((uintptr_t)&((struct direct *)0)->d_name +			\
114	  ((namlen)+1)*sizeof(((struct direct *)0)->d_name[0]) + 3) & ~3)
115#if (BYTE_ORDER == LITTLE_ENDIAN)
116#define	DIRSIZ(oldfmt, dp) \
117    ((oldfmt) ? DIRECTSIZ((dp)->d_type) : DIRECTSIZ((dp)->d_namlen))
118#else
119#define	DIRSIZ(oldfmt, dp) \
120    DIRECTSIZ((dp)->d_namlen)
121#endif
122#define	OLDDIRFMT	1
123#define	NEWDIRFMT	0
124
125/*
126 * Template for manipulating directories.  Should use struct direct's,
127 * but the name field is MAXNAMLEN - 1, and this just won't do.
128 */
129struct dirtemplate {
130	u_int32_t	dot_ino;
131	int16_t		dot_reclen;
132	u_int8_t	dot_type;
133	u_int8_t	dot_namlen;
134	char		dot_name[4];	/* must be multiple of 4 */
135	u_int32_t	dotdot_ino;
136	int16_t		dotdot_reclen;
137	u_int8_t	dotdot_type;
138	u_int8_t	dotdot_namlen;
139	char		dotdot_name[4];	/* ditto */
140};
141
142/*
143 * This is the old format of directories, sanz type element.
144 */
145struct odirtemplate {
146	u_int32_t	dot_ino;
147	int16_t		dot_reclen;
148	u_int16_t	dot_namlen;
149	char		dot_name[4];	/* must be multiple of 4 */
150	u_int32_t	dotdot_ino;
151	int16_t		dotdot_reclen;
152	u_int16_t	dotdot_namlen;
153	char		dotdot_name[4];	/* ditto */
154};
155#endif /* !_DIR_H_ */
156