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06f25585 DB |
1 | /* |
2 | * cramfs_common - cramfs common code | |
3 | * | |
4 | * Copyright (c) 2008 Roy Peled, the.roy.peled -at- gmail | |
5 | * Copyright (c) 2004-2006 by Michael Holzt, kju -at- fqdn.org | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | */ | |
18 | ||
63cccae4 KZ |
19 | #ifndef __CRAMFS_H |
20 | #define __CRAMFS_H | |
21 | ||
d51f37a3 | 22 | #include <stdint.h> |
63cccae4 KZ |
23 | |
24 | #define CRAMFS_MAGIC 0x28cd3d45 /* some random number */ | |
25 | #define CRAMFS_SIGNATURE "Compressed ROMFS" | |
26 | ||
27 | /* | |
28 | * Width of various bitfields in struct cramfs_inode. | |
29 | * Primarily used to generate warnings in mkcramfs. | |
30 | */ | |
31 | #define CRAMFS_MODE_WIDTH 16 | |
32 | #define CRAMFS_UID_WIDTH 16 | |
33 | #define CRAMFS_SIZE_WIDTH 24 | |
34 | #define CRAMFS_GID_WIDTH 8 | |
35 | #define CRAMFS_NAMELEN_WIDTH 6 | |
36 | #define CRAMFS_OFFSET_WIDTH 26 | |
37 | ||
06f25585 DB |
38 | #ifndef HOST_IS_BIG_ENDIAN |
39 | #ifdef WORDS_BIGENDIAN | |
40 | #define HOST_IS_BIG_ENDIAN 1 | |
41 | #else | |
42 | #define HOST_IS_BIG_ENDIAN 0 | |
43 | #endif | |
44 | #endif | |
63cccae4 KZ |
45 | |
46 | /* | |
47 | * Reasonably terse representation of the inode data. | |
48 | */ | |
49 | struct cramfs_inode { | |
d51f37a3 | 50 | uint32_t mode:16, uid:16; |
63cccae4 | 51 | /* SIZE for device files is i_rdev */ |
d51f37a3 | 52 | uint32_t size:24, gid:8; |
22eef91a SK |
53 | /* |
54 | * NAMELEN is the length of the file name, divided by 4 and | |
55 | * rounded up. (cramfs doesn't support hard links.) | |
56 | * | |
57 | * OFFSET: For symlinks and non-empty regular files, this | |
58 | * contains the offset (divided by 4) of the file data in | |
59 | * compressed form (starting with an array of block pointers; | |
60 | * see README). For non-empty directories it is the offset | |
61 | * (divided by 4) of the inode of the first file in that | |
62 | * directory. For anything else, offset is zero. | |
63 | */ | |
d51f37a3 | 64 | uint32_t namelen:6, offset:26; |
63cccae4 KZ |
65 | }; |
66 | ||
67 | struct cramfs_info { | |
22eef91a SK |
68 | uint32_t crc; |
69 | uint32_t edition; | |
70 | uint32_t blocks; | |
71 | uint32_t files; | |
63cccae4 KZ |
72 | }; |
73 | ||
74 | /* | |
75 | * Superblock information at the beginning of the FS. | |
76 | */ | |
77 | struct cramfs_super { | |
d51f37a3 SK |
78 | uint32_t magic; /* 0x28cd3d45 - random number */ |
79 | uint32_t size; /* Not used. mkcramfs currently | |
22eef91a | 80 | writes a constant 1<<16 here. */ |
d51f37a3 SK |
81 | uint32_t flags; /* 0 */ |
82 | uint32_t future; /* 0 */ | |
83 | uint8_t signature[16]; /* "Compressed ROMFS" */ | |
63cccae4 | 84 | struct cramfs_info fsid;/* unique filesystem info */ |
d51f37a3 | 85 | uint8_t name[16]; /* user-defined name */ |
63cccae4 KZ |
86 | struct cramfs_inode root; /* Root inode data */ |
87 | }; | |
88 | ||
22eef91a SK |
89 | #define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */ |
90 | #define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */ | |
91 | #define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */ | |
92 | #define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */ | |
93 | #define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */ | |
63cccae4 KZ |
94 | |
95 | /* | |
96 | * Valid values in super.flags. Currently we refuse to mount | |
97 | * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be | |
98 | * changed to test super.future instead. | |
99 | */ | |
100 | #define CRAMFS_SUPPORTED_FLAGS (0xff) | |
101 | ||
102 | /* Uncompression interfaces to the underlying zlib */ | |
103 | int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen); | |
104 | int cramfs_uncompress_init(void); | |
105 | int cramfs_uncompress_exit(void); | |
106 | ||
d51f37a3 | 107 | uint32_t u32_toggle_endianness(int big_endian, uint32_t what); |
06f25585 | 108 | void super_toggle_endianness(int from_big_endian, struct cramfs_super *super); |
22eef91a SK |
109 | void inode_to_host(int from_big_endian, struct cramfs_inode *inode_in, |
110 | struct cramfs_inode *inode_out); | |
111 | void inode_from_host(int to_big_endian, struct cramfs_inode *inode_in, | |
112 | struct cramfs_inode *inode_out); | |
06f25585 | 113 | |
63cccae4 | 114 | #endif |