1#ifndef __CRAMFS_H 2#define __CRAMFS_H 3 4#ifndef __KERNEL__ 5 6typedef unsigned char u8; 7typedef unsigned short u16; 8typedef 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 */ 35struct 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 50struct 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 */ 60struct 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 */ 94int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen); 95int cramfs_uncompress_init(void); 96int cramfs_uncompress_exit(void); 97 98#endif 99