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06f25585 | 1 | /* |
9e95aa12 KZ |
2 | * SPDX-License-Identifier: GPL-2.0-or-later |
3 | * | |
06f25585 DB |
4 | * cramfs_common - cramfs common code |
5 | * | |
6 | * Copyright (c) 2008 Roy Peled, the.roy.peled -at- gmail | |
cd42d02f | 7 | * Copyright (c) 2004-2006 by Juliane Holzt, kju -at- fqdn.org |
06f25585 DB |
8 | * |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
06f25585 | 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 | 38 | #ifndef HOST_IS_BIG_ENDIAN |
83b418c1 | 39 | #define HOST_IS_BIG_ENDIAN (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) |
06f25585 | 40 | #endif |
63cccae4 KZ |
41 | |
42 | /* | |
43 | * Reasonably terse representation of the inode data. | |
44 | */ | |
45 | struct cramfs_inode { | |
d51f37a3 | 46 | uint32_t mode:16, uid:16; |
63cccae4 | 47 | /* SIZE for device files is i_rdev */ |
d51f37a3 | 48 | uint32_t size:24, gid:8; |
22eef91a SK |
49 | /* |
50 | * NAMELEN is the length of the file name, divided by 4 and | |
51 | * rounded up. (cramfs doesn't support hard links.) | |
52 | * | |
53 | * OFFSET: For symlinks and non-empty regular files, this | |
54 | * contains the offset (divided by 4) of the file data in | |
55 | * compressed form (starting with an array of block pointers; | |
56 | * see README). For non-empty directories it is the offset | |
57 | * (divided by 4) of the inode of the first file in that | |
58 | * directory. For anything else, offset is zero. | |
59 | */ | |
d51f37a3 | 60 | uint32_t namelen:6, offset:26; |
63cccae4 KZ |
61 | }; |
62 | ||
63 | struct cramfs_info { | |
22eef91a SK |
64 | uint32_t crc; |
65 | uint32_t edition; | |
66 | uint32_t blocks; | |
67 | uint32_t files; | |
63cccae4 KZ |
68 | }; |
69 | ||
70 | /* | |
71 | * Superblock information at the beginning of the FS. | |
72 | */ | |
73 | struct cramfs_super { | |
d51f37a3 SK |
74 | uint32_t magic; /* 0x28cd3d45 - random number */ |
75 | uint32_t size; /* Not used. mkcramfs currently | |
22eef91a | 76 | writes a constant 1<<16 here. */ |
d51f37a3 SK |
77 | uint32_t flags; /* 0 */ |
78 | uint32_t future; /* 0 */ | |
79 | uint8_t signature[16]; /* "Compressed ROMFS" */ | |
63cccae4 | 80 | struct cramfs_info fsid;/* unique filesystem info */ |
d51f37a3 | 81 | uint8_t name[16]; /* user-defined name */ |
63cccae4 KZ |
82 | struct cramfs_inode root; /* Root inode data */ |
83 | }; | |
84 | ||
22eef91a SK |
85 | #define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */ |
86 | #define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */ | |
87 | #define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */ | |
88 | #define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */ | |
89 | #define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */ | |
63cccae4 KZ |
90 | |
91 | /* | |
92 | * Valid values in super.flags. Currently we refuse to mount | |
93 | * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be | |
94 | * changed to test super.future instead. | |
95 | */ | |
96 | #define CRAMFS_SUPPORTED_FLAGS (0xff) | |
97 | ||
98 | /* Uncompression interfaces to the underlying zlib */ | |
99 | int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen); | |
100 | int cramfs_uncompress_init(void); | |
101 | int cramfs_uncompress_exit(void); | |
102 | ||
d51f37a3 | 103 | uint32_t u32_toggle_endianness(int big_endian, uint32_t what); |
06f25585 | 104 | void super_toggle_endianness(int from_big_endian, struct cramfs_super *super); |
22eef91a SK |
105 | void inode_to_host(int from_big_endian, struct cramfs_inode *inode_in, |
106 | struct cramfs_inode *inode_out); | |
107 | void inode_from_host(int to_big_endian, struct cramfs_inode *inode_in, | |
108 | struct cramfs_inode *inode_out); | |
06f25585 | 109 | |
63cccae4 | 110 | #endif |