2017-11-01 21:08:43 +07:00
|
|
|
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
|
2012-10-13 16:46:48 +07:00
|
|
|
#ifndef _UAPI__CRAMFS_H
|
|
|
|
#define _UAPI__CRAMFS_H
|
|
|
|
|
|
|
|
#include <linux/types.h>
|
|
|
|
#include <linux/magic.h>
|
|
|
|
|
|
|
|
#define CRAMFS_SIGNATURE "Compressed ROMFS"
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Width of various bitfields in struct cramfs_inode.
|
|
|
|
* Primarily used to generate warnings in mkcramfs.
|
|
|
|
*/
|
|
|
|
#define CRAMFS_MODE_WIDTH 16
|
|
|
|
#define CRAMFS_UID_WIDTH 16
|
|
|
|
#define CRAMFS_SIZE_WIDTH 24
|
|
|
|
#define CRAMFS_GID_WIDTH 8
|
|
|
|
#define CRAMFS_NAMELEN_WIDTH 6
|
|
|
|
#define CRAMFS_OFFSET_WIDTH 26
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Since inode.namelen is a unsigned 6-bit number, the maximum cramfs
|
|
|
|
* path length is 63 << 2 = 252.
|
|
|
|
*/
|
|
|
|
#define CRAMFS_MAXPATHLEN (((1 << CRAMFS_NAMELEN_WIDTH) - 1) << 2)
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Reasonably terse representation of the inode data.
|
|
|
|
*/
|
|
|
|
struct cramfs_inode {
|
|
|
|
__u32 mode:CRAMFS_MODE_WIDTH, uid:CRAMFS_UID_WIDTH;
|
|
|
|
/* SIZE for device files is i_rdev */
|
|
|
|
__u32 size:CRAMFS_SIZE_WIDTH, gid:CRAMFS_GID_WIDTH;
|
|
|
|
/* NAMELEN is the length of the file name, divided by 4 and
|
|
|
|
rounded up. (cramfs doesn't support hard links.) */
|
|
|
|
/* OFFSET: For symlinks and non-empty regular files, this
|
|
|
|
contains the offset (divided by 4) of the file data in
|
|
|
|
compressed form (starting with an array of block pointers;
|
|
|
|
see README). For non-empty directories it is the offset
|
|
|
|
(divided by 4) of the inode of the first file in that
|
|
|
|
directory. For anything else, offset is zero. */
|
|
|
|
__u32 namelen:CRAMFS_NAMELEN_WIDTH, offset:CRAMFS_OFFSET_WIDTH;
|
|
|
|
};
|
|
|
|
|
|
|
|
struct cramfs_info {
|
|
|
|
__u32 crc;
|
|
|
|
__u32 edition;
|
|
|
|
__u32 blocks;
|
|
|
|
__u32 files;
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Superblock information at the beginning of the FS.
|
|
|
|
*/
|
|
|
|
struct cramfs_super {
|
|
|
|
__u32 magic; /* 0x28cd3d45 - random number */
|
|
|
|
__u32 size; /* length in bytes */
|
|
|
|
__u32 flags; /* feature flags */
|
|
|
|
__u32 future; /* reserved for future use */
|
|
|
|
__u8 signature[16]; /* "Compressed ROMFS" */
|
|
|
|
struct cramfs_info fsid; /* unique filesystem info */
|
|
|
|
__u8 name[16]; /* user-defined name */
|
|
|
|
struct cramfs_inode root; /* root inode data */
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Feature flags
|
|
|
|
*
|
|
|
|
* 0x00000000 - 0x000000ff: features that work for all past kernels
|
|
|
|
* 0x00000100 - 0xffffffff: features that don't work for past kernels
|
|
|
|
*/
|
|
|
|
#define CRAMFS_FLAG_FSID_VERSION_2 0x00000001 /* fsid version #2 */
|
|
|
|
#define CRAMFS_FLAG_SORTED_DIRS 0x00000002 /* sorted dirs */
|
|
|
|
#define CRAMFS_FLAG_HOLES 0x00000100 /* support for holes */
|
|
|
|
#define CRAMFS_FLAG_WRONG_SIGNATURE 0x00000200 /* reserved */
|
|
|
|
#define CRAMFS_FLAG_SHIFTED_ROOT_OFFSET 0x00000400 /* shifted root fs */
|
2017-10-12 13:16:11 +07:00
|
|
|
#define CRAMFS_FLAG_EXT_BLOCK_POINTERS 0x00000800 /* block pointer extensions */
|
2012-10-13 16:46:48 +07:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Valid values in super.flags. Currently we refuse to mount
|
|
|
|
* if (flags & ~CRAMFS_SUPPORTED_FLAGS). Maybe that should be
|
|
|
|
* changed to test super.future instead.
|
|
|
|
*/
|
|
|
|
#define CRAMFS_SUPPORTED_FLAGS ( 0x000000ff \
|
|
|
|
| CRAMFS_FLAG_HOLES \
|
|
|
|
| CRAMFS_FLAG_WRONG_SIGNATURE \
|
2017-10-12 13:16:11 +07:00
|
|
|
| CRAMFS_FLAG_SHIFTED_ROOT_OFFSET \
|
|
|
|
| CRAMFS_FLAG_EXT_BLOCK_POINTERS )
|
2012-10-13 16:46:48 +07:00
|
|
|
|
2017-10-12 13:16:11 +07:00
|
|
|
/*
|
|
|
|
* Block pointer flags
|
|
|
|
*
|
|
|
|
* The maximum block offset that needs to be represented is roughly:
|
|
|
|
*
|
|
|
|
* (1 << CRAMFS_OFFSET_WIDTH) * 4 +
|
|
|
|
* (1 << CRAMFS_SIZE_WIDTH) / PAGE_SIZE * (4 + PAGE_SIZE)
|
|
|
|
* = 0x11004000
|
|
|
|
*
|
|
|
|
* That leaves room for 3 flag bits in the block pointer table.
|
|
|
|
*/
|
|
|
|
#define CRAMFS_BLK_FLAG_UNCOMPRESSED (1 << 31)
|
|
|
|
#define CRAMFS_BLK_FLAG_DIRECT_PTR (1 << 30)
|
|
|
|
|
|
|
|
#define CRAMFS_BLK_FLAGS ( CRAMFS_BLK_FLAG_UNCOMPRESSED \
|
|
|
|
| CRAMFS_BLK_FLAG_DIRECT_PTR )
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Direct blocks are at least 4-byte aligned.
|
|
|
|
* Pointers to direct blocks are shifted down by 2 bits.
|
|
|
|
*/
|
|
|
|
#define CRAMFS_BLK_DIRECT_PTR_SHIFT 2
|
2012-10-13 16:46:48 +07:00
|
|
|
|
|
|
|
#endif /* _UAPI__CRAMFS_H */
|