/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */#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 */#define CRAMFS_FLAG_EXT_BLOCK_POINTERS	0x00000800	/* block pointer extensions */ /* * 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 \				| CRAMFS_FLAG_SHIFTED_ROOT_OFFSET \				| CRAMFS_FLAG_EXT_BLOCK_POINTERS ) /* * 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 #endif /* _UAPI__CRAMFS_H */