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/*
* cramfs_common - cramfs common code
*
* Copyright (c) 2008 Roy Peled, the.roy.peled -at- gmail
* Copyright (c) 2004-2006 by Juliane Holzt, kju -at- fqdn.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#ifndef __CRAMFS_H
#define __CRAMFS_H
#include <stdint.h>
#define CRAMFS_MAGIC 0x28cd3d45 /* some random number */
#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
#ifndef HOST_IS_BIG_ENDIAN
#ifdef WORDS_BIGENDIAN
#define HOST_IS_BIG_ENDIAN 1
#else
#define HOST_IS_BIG_ENDIAN 0
#endif
#endif
/*
* Reasonably terse representation of the inode data.
*/
struct cramfs_inode {
uint32_t mode:16, uid:16;
/* SIZE for device files is i_rdev */
uint32_t size:24, gid:8;
/*
* 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.
*/
uint32_t namelen:6, offset:26;
};
struct cramfs_info {
uint32_t crc;
uint32_t edition;
uint32_t blocks;
uint32_t files;
};
/*
* Superblock information at the beginning of the FS.
*/
struct cramfs_super {
uint32_t magic; /* 0x28cd3d45 - random number */
uint32_t size; /* Not used. mkcramfs currently
writes a constant 1<<16 here. */
uint32_t flags; /* 0 */
uint32_t future; /* 0 */
uint8_t signature[16]; /* "Compressed ROMFS" */
struct cramfs_info fsid;/* unique filesystem info */
uint8_t name[16]; /* user-defined name */
struct cramfs_inode root; /* Root inode data */
};
#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 */
/*
* 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 (0xff)
/* Uncompression interfaces to the underlying zlib */
int cramfs_uncompress_block(void *dst, int dstlen, void *src, int srclen);
int cramfs_uncompress_init(void);
int cramfs_uncompress_exit(void);
uint32_t u32_toggle_endianness(int big_endian, uint32_t what);
void super_toggle_endianness(int from_big_endian, struct cramfs_super *super);
void inode_to_host(int from_big_endian, struct cramfs_inode *inode_in,
struct cramfs_inode *inode_out);
void inode_from_host(int to_big_endian, struct cramfs_inode *inode_in,
struct cramfs_inode *inode_out);
#endif
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