aboutsummaryrefslogtreecommitdiff
path: root/include/sqfs/dir.h
blob: 1a1ce012a7faf70a105813caecf644e4e50f3575 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
 * dir.h - This file is part of libsquashfs
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#ifndef SQFS_DIR_H
#define SQFS_DIR_H

#include "sqfs/predef.h"

/**
 * @file dir.h
 *
 * @brief Contains on-disk data structures for the directory table and
 *        declarations for the @ref sqfs_dir_writer_t.
 */

#define SQFS_MAX_DIR_ENT 256

/**
 * @struct sqfs_dir_header_t
 *
 * @brief On-disk data structure of a directory header
 *
 * See @ref sqfs_dir_writer_t for an overview on how SquashFS stores
 * directories on disk.
 */
struct sqfs_dir_header_t {
	/**
	 * @brief The number of @ref sqfs_dir_entry_t entries that are
	 *        following.
	 *
	 * This value is stored off by one and the total count must not
	 * exceed 256.
	 */
	sqfs_u32 count;

	/**
	 * @brief The location of the meta data block containing the inodes for
	 *        the entries that follow, relative to the start of the inode
	 *        table.
	 */
	sqfs_u32 start_block;

	/**
	 * @brief The inode number of the first entry.
	 */
	sqfs_u32 inode_number;
};

/**
 * @struct sqfs_dir_entry_t
 *
 * @brief On-disk data structure of a directory entry. Many of these
 *        follow a single @ref sqfs_dir_header_t.
 *
 * See @ref sqfs_dir_writer_t for an overview on how SquashFS stores
 * directories on disk.
 */
struct sqfs_dir_entry_t {
	/**
	 * @brief An offset into the uncompressed meta data block containing
	 *        the coresponding inode.
	 */
	sqfs_u16 offset;

	/**
	 * @brief Signed difference of the inode number from the one
	 *        in the @ref sqfs_dir_header_t.
	 */
	sqfs_s16 inode_diff;

	/**
	 * @brief The @ref E_SQFS_INODE_TYPE value for the inode that this
	 *        entry represents.
	 */
	sqfs_u16 type;

	/**
	 * @brief The size of the entry name
	 *
	 * This value is stored off-by-one.
	 */
	sqfs_u16 size;

	/**
	 * @brief The name of the directory entry (no trailing null-byte).
	 */
	sqfs_u8 name[];
};

/**
 * @struct sqfs_dir_index_t
 *
 * @brief On-disk data structure of a directory index. A series of those
 *        can follow an @ref sqfs_inode_dir_ext_t.
 *
 * See @ref sqfs_dir_writer_t for an overview on how SquashFS stores
 * directories on disk.
 */
struct sqfs_dir_index_t {
	/**
	 * @brief Linear byte offset into the decompressed directory listing.
	 */
	sqfs_u32 index;

	/**
	 * @brief Location of the meta data block, relative to the directory
	 *        table start.
	 */
	sqfs_u32 start_block;

	/**
	 * @brief Size of the name of the first entry after the header.
	 *
	 * This value is stored off-by-one.
	 */
	sqfs_u32 size;

	/**
	 * @brief Name of the name of the first entry after the header.
	 *
	 * No trailing null-byte.
	 */
	sqfs_u8 name[];
};

#endif /* SQFS_DIR_H */