xref: /illumos-gate/usr/src/boot/include/ufs/ufs/dir.h (revision 8130c4e1)
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  */
36 
37 #ifndef _UFS_UFS_DIR_H_
38 #define	_UFS_UFS_DIR_H_
39 
40 /*
41  * Theoretically, directories can be more than 2Gb in length, however, in
42  * practice this seems unlikely. So, we define the type doff_t as a 32-bit
43  * quantity to keep down the cost of doing lookup on a 32-bit machine.
44  */
45 #define	doff_t		int32_t
46 #define	MAXDIRSIZE	(0x7fffffff)
47 
48 /*
49  * A directory consists of some number of blocks of DIRBLKSIZ
50  * bytes, where DIRBLKSIZ is chosen such that it can be transferred
51  * to disk in a single atomic operation (e.g. 512 bytes on most machines).
52  *
53  * Each DIRBLKSIZ byte block contains some number of directory entry
54  * structures, which are of variable length.  Each directory entry has
55  * a struct direct at the front of it, containing its inode number,
56  * the length of the entry, and the length of the name contained in
57  * the entry.  These are followed by the name padded to a 4 byte boundary
58  * with null bytes.  All names are guaranteed null terminated.
59  * The maximum length of a name in a directory is UFS_MAXNAMLEN.
60  *
61  * The macro DIRSIZ(fmt, dp) gives the amount of space required to represent
62  * a directory entry.  Free space in a directory is represented by
63  * entries which have dp->d_reclen > DIRSIZ(fmt, dp).  All DIRBLKSIZ bytes
64  * in a directory block are claimed by the directory entries.  This
65  * usually results in the last entry in a directory having a large
66  * dp->d_reclen.  When entries are deleted from a directory, the
67  * space is returned to the previous entry in the same directory
68  * block by increasing its dp->d_reclen.  If the first entry of
69  * a directory block is free, then its dp->d_ino is set to 0.
70  * Entries other than the first in a directory do not normally have
71  * dp->d_ino set to 0.
72  */
73 #define	DIRBLKSIZ	DEV_BSIZE
74 #define	UFS_MAXNAMLEN	255
75 
76 struct	direct {
77 	u_int32_t d_ino;		/* inode number of entry */
78 	u_int16_t d_reclen;		/* length of this record */
79 	u_int16_t d_namlen;		/* length of string in d_name */
80 	char	  d_name[UFS_MAXNAMLEN + 1];
81 				/* name with length <= UFS_MAXNAMLEN */
82 };
83 
84 /*
85  * File types
86  */
87 #define	DT_UNKNOWN	 0
88 #define	DT_FIFO		 1
89 #define	DT_CHR		 2
90 #define	DT_DIR		 4
91 #define	DT_BLK		 6
92 #define	DT_REG		 8
93 #define	DT_LNK		10
94 #define	DT_SOCK		12
95 #define	DT_WHT		14
96 
97 /*
98  * Convert between stat structure types and directory types.
99  */
100 #define	IFTODT(mode)	(((mode) & 0170000) >> 12)
101 #define	DTTOIF(dirtype)	((dirtype) << 12)
102 
103 /*
104  * The DIRSIZ macro gives the minimum record length which will hold
105  * the directory entry.  This requires the amount of space in struct direct
106  * without the d_name field, plus enough space for the name with a terminating
107  * null byte (dp->d_namlen+1), rounded up to a 4 byte boundary.
108  *
109  *
110  */
111 #define	DIRECTSIZ(namlen)						\
112 	((__offsetof(struct direct, d_name) +				\
113 	  ((namlen)+1)*sizeof(((struct direct *)0)->d_name[0]) + 3) & ~3)
114 #if (BYTE_ORDER == LITTLE_ENDIAN)
115 #define	DIRSIZ(oldfmt, dp) \
116     ((oldfmt) ? DIRECTSIZ((dp)->d_type) : DIRECTSIZ((dp)->d_namlen))
117 #else
118 #define	DIRSIZ(oldfmt, dp) \
119     DIRECTSIZ((dp)->d_namlen)
120 #endif
121 #define	OLDDIRFMT	1
122 #define	NEWDIRFMT	0
123 
124 /*
125  * Template for manipulating directories.  Should use struct direct's,
126  * but the name field is UFS_MAXNAMLEN - 1, and this just won't do.
127  */
128 struct dirtemplate {
129 	u_int32_t	dot_ino;
130 	int16_t		dot_reclen;
131 	u_int8_t	dot_type;
132 	u_int8_t	dot_namlen;
133 	char		dot_name[4];	/* must be multiple of 4 */
134 	u_int32_t	dotdot_ino;
135 	int16_t		dotdot_reclen;
136 	u_int8_t	dotdot_type;
137 	u_int8_t	dotdot_namlen;
138 	char		dotdot_name[4];	/* ditto */
139 };
140 
141 /*
142  * This is the old format of directories, sanz type element.
143  */
144 struct odirtemplate {
145 	u_int32_t	dot_ino;
146 	int16_t		dot_reclen;
147 	u_int16_t	dot_namlen;
148 	char		dot_name[4];	/* must be multiple of 4 */
149 	u_int32_t	dotdot_ino;
150 	int16_t		dotdot_reclen;
151 	u_int16_t	dotdot_namlen;
152 	char		dotdot_name[4];	/* ditto */
153 };
154 #endif /* !_DIR_H_ */
155