xref: /freebsd/sys/fs/ext2fs/ext2_dir.h (revision ccfd87fe2ac0e2e6aeb1911a7d7cce6712a8564f)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2009 Aditya Sarawgi
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #ifndef _FS_EXT2FS_EXT2_DIR_H_
32 #define	_FS_EXT2FS_EXT2_DIR_H_
33 
34 /*
35  * Structure of a directory entry
36  */
37 #define	EXT2FS_MAXNAMLEN	255
38 
39 struct ext2fs_direct {
40 	uint32_t e2d_ino;		/* inode number of entry */
41 	uint16_t e2d_reclen;		/* length of this record */
42 	uint16_t e2d_namlen;		/* length of string in e2d_name */
43 	char e2d_name[EXT2FS_MAXNAMLEN];/* name with length<=EXT2FS_MAXNAMLEN */
44 };
45 
46 enum slotstatus {
47 	NONE,
48 	COMPACT,
49 	FOUND
50 };
51 
52 struct ext2fs_searchslot {
53 	enum slotstatus slotstatus;
54 	doff_t	slotoffset;		/* offset of area with free space */
55 	int	slotsize;		/* size of area at slotoffset */
56 	int	slotfreespace;		/* amount of space free in slot */
57 	int	slotneeded;		/* sizeof the entry we are seeking */
58 };
59 
60 /*
61  * The new version of the directory entry.  Since EXT2 structures are
62  * stored in intel byte order, and the name_len field could never be
63  * bigger than 255 chars, it's safe to reclaim the extra byte for the
64  * file_type field.
65  */
66 struct ext2fs_direct_2 {
67 	uint32_t e2d_ino;		/* inode number of entry */
68 	uint16_t e2d_reclen;		/* length of this record */
69 	uint8_t	e2d_namlen;		/* length of string in e2d_name */
70 	uint8_t	e2d_type;		/* file type */
71 	char	e2d_name[EXT2FS_MAXNAMLEN];	/* name with
72 						 * length<=EXT2FS_MAXNAMLEN */
73 };
74 
75 struct ext2fs_direct_tail {
76 	uint32_t e2dt_reserved_zero1;	/* pretend to be unused */
77 	uint16_t e2dt_rec_len;		/* 12 */
78 	uint8_t	e2dt_reserved_zero2;	/* zero name length */
79 	uint8_t	e2dt_reserved_ft;	/* 0xDE, fake file type */
80 	uint32_t e2dt_checksum;		/* crc32c(uuid+inum+dirblock) */
81 };
82 
83 #define EXT2_FT_DIR_CSUM	0xDE
84 
85 #define EXT2_DIRENT_TAIL(data, blocksize) \
86 	((struct ext2fs_direct_tail *)(((char *)(data)) + \
87 	(blocksize) - sizeof(struct ext2fs_direct_tail)))
88 
89 /*
90  * Maximal count of links to a file
91  */
92 #define	EXT4_LINK_MAX	65000
93 
94 /*
95  * Ext2 directory file types.  Only the low 3 bits are used.  The
96  * other bits are reserved for now.
97  */
98 #define	EXT2_FT_UNKNOWN		0
99 #define	EXT2_FT_REG_FILE	1
100 #define	EXT2_FT_DIR		2
101 #define	EXT2_FT_CHRDEV		3
102 #define	EXT2_FT_BLKDEV 		4
103 #define	EXT2_FT_FIFO		5
104 #define	EXT2_FT_SOCK		6
105 #define	EXT2_FT_SYMLINK		7
106 #define	EXT2_FT_MAX		8
107 
108 /*
109  * EXT2_DIR_PAD defines the directory entries boundaries
110  *
111  * NOTE: It must be a multiple of 4
112  */
113 #define	EXT2_DIR_PAD		 	4
114 #define	EXT2_DIR_ROUND			(EXT2_DIR_PAD - 1)
115 #define	EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \
116 					 ~EXT2_DIR_ROUND)
117 #endif	/* !_FS_EXT2FS_EXT2_DIR_H_ */
118