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wdenkdd875c72004-01-03 21:24:46 +00001#ifndef __CRAMFS_H
2#define __CRAMFS_H
3
wdenkdd875c72004-01-03 21:24:46 +00004#define CRAMFS_MAGIC 0x28cd3d45 /* some random number */
5#define CRAMFS_SIGNATURE "Compressed ROMFS"
6
7/*
8 * Width of various bitfields in struct cramfs_inode.
9 * Primarily used to generate warnings in mkcramfs.
10 */
wdenk180d3f72004-01-04 16:28:35 +000011#define CRAMFS_MODE_WIDTH 16
12#define CRAMFS_UID_WIDTH 16
13#define CRAMFS_SIZE_WIDTH 24
14#define CRAMFS_GID_WIDTH 8
15#define CRAMFS_NAMELEN_WIDTH 6
16#define CRAMFS_OFFSET_WIDTH 26
wdenkdd875c72004-01-03 21:24:46 +000017
18/*
19 * Since inode.namelen is a unsigned 6-bit number, the maximum cramfs
20 * path length is 63 << 2 = 252.
21 */
22#define CRAMFS_MAXPATHLEN (((1 << CRAMFS_NAMELEN_WIDTH) - 1) << 2)
23
24/*
25 * Reasonably terse representation of the inode data.
26 */
27struct cramfs_inode {
28 u32 mode:CRAMFS_MODE_WIDTH, uid:CRAMFS_UID_WIDTH;
wdenk180d3f72004-01-04 16:28:35 +000029
wdenkdd875c72004-01-03 21:24:46 +000030 /* SIZE for device files is i_rdev */
31 u32 size:CRAMFS_SIZE_WIDTH, gid:CRAMFS_GID_WIDTH;
wdenk180d3f72004-01-04 16:28:35 +000032
wdenkdd875c72004-01-03 21:24:46 +000033 /* NAMELEN is the length of the file name, divided by 4 and
34 rounded up. (cramfs doesn't support hard links.) */
35 /* OFFSET: For symlinks and non-empty regular files, this
36 contains the offset (divided by 4) of the file data in
37 compressed form (starting with an array of block pointers;
38 see README). For non-empty directories it is the offset
39 (divided by 4) of the inode of the first file in that
40 directory. For anything else, offset is zero. */
41 u32 namelen:CRAMFS_NAMELEN_WIDTH, offset:CRAMFS_OFFSET_WIDTH;
42};
43
44struct cramfs_info {
45 u32 crc;
46 u32 edition;
47 u32 blocks;
48 u32 files;
49};
50
51/*
52 * Superblock information at the beginning of the FS.
53 */
54struct cramfs_super {
55 u32 magic; /* 0x28cd3d45 - random number */
56 u32 size; /* length in bytes */
57 u32 flags; /* feature flags */
58 u32 future; /* reserved for future use */
59 u8 signature[16]; /* "Compressed ROMFS" */
60 struct cramfs_info fsid; /* unique filesystem info */
61 u8 name[16]; /* user-defined name */
62 struct cramfs_inode root; /* root inode data */
63};
64
65/*
66 * Feature flags
67 *
68 * 0x00000000 - 0x000000ff: features that work for all past kernels
69 * 0x00000100 - 0xffffffff: features that don't work for past kernels
70 */
71#define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */
72#define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */
73#define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */
74#define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */
75#define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */
76
77/*
78 * Valid values in super.flags. Currently we refuse to mount
79 * if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be
80 * changed to test super.future instead.
81 */
82#define CRAMFS_SUPPORTED_FLAGS ( 0x000000ff \
83 | CRAMFS_FLAG_HOLES \
84 | CRAMFS_FLAG_WRONG_SIGNATURE \
85 | CRAMFS_FLAG_SHIFTED_ROOT_OFFSET )
86
wdenk180d3f72004-01-04 16:28:35 +000087#define CRAMFS_16(x) (x)
88#define CRAMFS_24(x) (x)
89#define CRAMFS_32(x) (x)
90#define CRAMFS_GET_NAMELEN(x) ((x)->namelen)
91#define CRAMFS_GET_OFFSET(x) ((x)->offset)
92#define CRAMFS_SET_OFFSET(x,y) ((x)->offset = (y))
93#define CRAMFS_SET_NAMELEN(x,y) ((x)->namelen = (y))
wdenk180d3f72004-01-04 16:28:35 +000094
wdenkdd875c72004-01-03 21:24:46 +000095/* Uncompression interfaces to the underlying zlib */
wdenk180d3f72004-01-04 16:28:35 +000096int cramfs_uncompress_block(void *dst, void *src, int srclen);
wdenkdd875c72004-01-03 21:24:46 +000097int cramfs_uncompress_init(void);
98int cramfs_uncompress_exit(void);
99
wdenk180d3f72004-01-04 16:28:35 +0000100#endif /* __CRAMFS_H */