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1da177e4 LT |
1 | #ifndef __CRAMFS_H |
2 | #define __CRAMFS_H | |
3 | ||
4 | #ifndef __KERNEL__ | |
5 | ||
6 | typedef unsigned char u8; | |
7 | typedef unsigned short u16; | |
8 | typedef unsigned int u32; | |
9 | ||
10 | #endif | |
11 | ||
12 | #define CRAMFS_MAGIC 0x28cd3d45 /* some random number */ | |
13 | #define CRAMFS_SIGNATURE "Compressed ROMFS" | |
14 | ||
15 | /* | |
16 | * Width of various bitfields in struct cramfs_inode. | |
17 | * Primarily used to generate warnings in mkcramfs. | |
18 | */ | |
19 | #define CRAMFS_MODE_WIDTH 16 | |
20 | #define CRAMFS_UID_WIDTH 16 | |
21 | #define CRAMFS_SIZE_WIDTH 24 | |
22 | #define CRAMFS_GID_WIDTH 8 | |
23 | #define CRAMFS_NAMELEN_WIDTH 6 | |
24 | #define CRAMFS_OFFSET_WIDTH 26 | |
25 | ||
26 | /* | |
27 | * Since inode.namelen is a unsigned 6-bit number, the maximum cramfs | |
28 | * path length is 63 << 2 = 252. | |
29 | */ | |
30 | #define CRAMFS_MAXPATHLEN (((1 << CRAMFS_NAMELEN_WIDTH) - 1) << 2) | |
31 | ||
32 | /* | |
33 | * Reasonably terse representation of the inode data. | |
34 | */ | |
35 | struct cramfs_inode { | |
36 | u32 mode:CRAMFS_MODE_WIDTH, uid:CRAMFS_UID_WIDTH; | |
37 | /* SIZE for device files is i_rdev */ | |
38 | u32 size:CRAMFS_SIZE_WIDTH, gid:CRAMFS_GID_WIDTH; | |
39 | /* NAMELEN is the length of the file name, divided by 4 and | |
40 | rounded up. (cramfs doesn't support hard links.) */ | |
41 | /* OFFSET: For symlinks and non-empty regular files, this | |
42 | contains the offset (divided by 4) of the file data in | |
43 | compressed form (starting with an array of block pointers; | |
44 | see README). For non-empty directories it is the offset | |
45 | (divided by 4) of the inode of the first file in that | |
46 | directory. For anything else, offset is zero. */ | |
47 | u32 namelen:CRAMFS_NAMELEN_WIDTH, offset:CRAMFS_OFFSET_WIDTH; | |
48 | }; | |
49 | ||
50 | struct cramfs_info { | |
51 | u32 crc; | |
52 | u32 edition; | |
53 | u32 blocks; | |
54 | u32 files; | |
55 | }; | |
56 | ||
57 | /* | |
58 | * Superblock information at the beginning of the FS. | |
59 | */ | |
60 | struct cramfs_super { | |
61 | u32 magic; /* 0x28cd3d45 - random number */ | |
62 | u32 size; /* length in bytes */ | |
63 | u32 flags; /* feature flags */ | |
64 | u32 future; /* reserved for future use */ | |
65 | u8 signature[16]; /* "Compressed ROMFS" */ | |
66 | struct cramfs_info fsid; /* unique filesystem info */ | |
67 | u8 name[16]; /* user-defined name */ | |
68 | struct cramfs_inode root; /* root inode data */ | |
69 | }; | |
70 | ||
71 | /* | |
72 | * Feature flags | |
73 | * | |
74 | * 0x00000000 - 0x000000ff: features that work for all past kernels | |
75 | * 0x00000100 - 0xffffffff: features that don't work for past kernels | |
76 | */ | |
77 | #define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */ | |
78 | #define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */ | |
79 | #define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */ | |
80 | #define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */ | |
81 | #define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */ | |
82 | ||
83 | /* | |
84 | * Valid values in super.flags. Currently we refuse to mount | |
85 | * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be | |
86 | * changed to test super.future instead. | |
87 | */ | |
88 | #define CRAMFS_SUPPORTED_FLAGS ( 0x000000ff \ | |
89 | | CRAMFS_FLAG_HOLES \ | |
90 | | CRAMFS_FLAG_WRONG_SIGNATURE \ | |
91 | | CRAMFS_FLAG_SHIFTED_ROOT_OFFSET ) | |
92 | ||
93 | /* Uncompression interfaces to the underlying zlib */ | |
94 | int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen); | |
95 | int cramfs_uncompress_init(void); | |
96 | int cramfs_uncompress_exit(void); | |
97 | ||
98 | #endif |