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 99