projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 607ca46e DH |
1 | #ifndef _UAPI__CRAMFS_H |
| 2 | #define _UAPI__CRAMFS_H | |
| 3 | ||
| 4 | #include <linux/types.h> | |
| 5 | #include <linux/magic.h> | |
| 6 | ||
| 7 | #define CRAMFS_SIGNATURE "Compressed ROMFS" | |
| 8 | ||
| 9 | /* | |
| 10 | * Width of various bitfields in struct cramfs_inode. | |
| 11 | * Primarily used to generate warnings in mkcramfs. | |
| 12 | */ | |
| 13 | #define CRAMFS_MODE_WIDTH 16 | |
| 14 | #define CRAMFS_UID_WIDTH 16 | |
| 15 | #define CRAMFS_SIZE_WIDTH 24 | |
| 16 | #define CRAMFS_GID_WIDTH 8 | |
| 17 | #define CRAMFS_NAMELEN_WIDTH 6 | |
| 18 | #define CRAMFS_OFFSET_WIDTH 26 | |
| 19 | ||
| 20 | /* | |
| 21 | * Since inode.namelen is a unsigned 6-bit number, the maximum cramfs | |
| 22 | * path length is 63 << 2 = 252. | |
| 23 | */ | |
| 24 | #define CRAMFS_MAXPATHLEN (((1 << CRAMFS_NAMELEN_WIDTH) - 1) << 2) | |
| 25 | ||
| 26 | /* | |
| 27 | * Reasonably terse representation of the inode data. | |
| 28 | */ | |
| 29 | struct cramfs_inode { | |
| 30 | __u32 mode:CRAMFS_MODE_WIDTH, uid:CRAMFS_UID_WIDTH; | |
| 31 | /* SIZE for device files is i_rdev */ | |
| 32 | __u32 size:CRAMFS_SIZE_WIDTH, gid:CRAMFS_GID_WIDTH; | |
| 33 | /* 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 | ||
| 44 | struct 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 | */ | |
| 54 | struct 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 | ||
| 87 | ||
| 88 | #endif /* _UAPI__CRAMFS_H */ |