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1da177e4 LT |
1 | #ifndef __CRAMFS_H |
2 | #define __CRAMFS_H | |
3 | ||
05f75fd3 | 4 | #include <linux/types.h> |
1da177e4 LT |
5 | |
6 | #define CRAMFS_MAGIC 0x28cd3d45 /* some random number */ | |
ac8d35c5 | 7 | #define CRAMFS_MAGIC_WEND 0x453dcd28 /* magic number with the wrong endianess */ |
1da177e4 LT |
8 | #define CRAMFS_SIGNATURE "Compressed ROMFS" |
9 | ||
10 | /* | |
11 | * Width of various bitfields in struct cramfs_inode. | |
12 | * Primarily used to generate warnings in mkcramfs. | |
13 | */ | |
14 | #define CRAMFS_MODE_WIDTH 16 | |
15 | #define CRAMFS_UID_WIDTH 16 | |
16 | #define CRAMFS_SIZE_WIDTH 24 | |
17 | #define CRAMFS_GID_WIDTH 8 | |
18 | #define CRAMFS_NAMELEN_WIDTH 6 | |
19 | #define CRAMFS_OFFSET_WIDTH 26 | |
20 | ||
21 | /* | |
22 | * Since inode.namelen is a unsigned 6-bit number, the maximum cramfs | |
23 | * path length is 63 << 2 = 252. | |
24 | */ | |
25 | #define CRAMFS_MAXPATHLEN (((1 << CRAMFS_NAMELEN_WIDTH) - 1) << 2) | |
26 | ||
27 | /* | |
28 | * Reasonably terse representation of the inode data. | |
29 | */ | |
30 | struct cramfs_inode { | |
05f75fd3 | 31 | __u32 mode:CRAMFS_MODE_WIDTH, uid:CRAMFS_UID_WIDTH; |
1da177e4 | 32 | /* SIZE for device files is i_rdev */ |
05f75fd3 | 33 | __u32 size:CRAMFS_SIZE_WIDTH, gid:CRAMFS_GID_WIDTH; |
1da177e4 LT |
34 | /* NAMELEN is the length of the file name, divided by 4 and |
35 | rounded up. (cramfs doesn't support hard links.) */ | |
36 | /* OFFSET: For symlinks and non-empty regular files, this | |
37 | contains the offset (divided by 4) of the file data in | |
38 | compressed form (starting with an array of block pointers; | |
39 | see README). For non-empty directories it is the offset | |
40 | (divided by 4) of the inode of the first file in that | |
41 | directory. For anything else, offset is zero. */ | |
05f75fd3 | 42 | __u32 namelen:CRAMFS_NAMELEN_WIDTH, offset:CRAMFS_OFFSET_WIDTH; |
1da177e4 LT |
43 | }; |
44 | ||
45 | struct cramfs_info { | |
05f75fd3 DW |
46 | __u32 crc; |
47 | __u32 edition; | |
48 | __u32 blocks; | |
49 | __u32 files; | |
1da177e4 LT |
50 | }; |
51 | ||
52 | /* | |
53 | * Superblock information at the beginning of the FS. | |
54 | */ | |
55 | struct cramfs_super { | |
05f75fd3 DW |
56 | __u32 magic; /* 0x28cd3d45 - random number */ |
57 | __u32 size; /* length in bytes */ | |
58 | __u32 flags; /* feature flags */ | |
59 | __u32 future; /* reserved for future use */ | |
60 | __u8 signature[16]; /* "Compressed ROMFS" */ | |
1da177e4 | 61 | struct cramfs_info fsid; /* unique filesystem info */ |
05f75fd3 | 62 | __u8 name[16]; /* user-defined name */ |
1da177e4 LT |
63 | struct cramfs_inode root; /* root inode data */ |
64 | }; | |
65 | ||
66 | /* | |
67 | * Feature flags | |
68 | * | |
69 | * 0x00000000 - 0x000000ff: features that work for all past kernels | |
70 | * 0x00000100 - 0xffffffff: features that don't work for past kernels | |
71 | */ | |
72 | #define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */ | |
73 | #define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */ | |
74 | #define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */ | |
75 | #define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */ | |
76 | #define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */ | |
77 | ||
78 | /* | |
79 | * Valid values in super.flags. Currently we refuse to mount | |
80 | * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be | |
81 | * changed to test super.future instead. | |
82 | */ | |
83 | #define CRAMFS_SUPPORTED_FLAGS ( 0x000000ff \ | |
84 | | CRAMFS_FLAG_HOLES \ | |
85 | | CRAMFS_FLAG_WRONG_SIGNATURE \ | |
86 | | CRAMFS_FLAG_SHIFTED_ROOT_OFFSET ) | |
87 | ||
88 | /* Uncompression interfaces to the underlying zlib */ | |
89 | int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen); | |
90 | int cramfs_uncompress_init(void); | |
368bdb3d | 91 | void cramfs_uncompress_exit(void); |
1da177e4 LT |
92 | |
93 | #endif |