squashfs_fs.h

一款linux的文件系统

extern int squashfs_uncompress_block(void *d, int dstlen, void *s, int srclen);
extern int squashfs_uncompress_init(void);
extern int squashfs_uncompress_exit(void);

/*
 * macros to convert each packed bitfield structure from little endian to big
 * endian and vice versa.  These are needed when creating or using a filesystem on a
 * machine with different byte ordering to the target architecture.
 *
 */

#define SQUASHFS_SWAP_SUPER_BLOCK(s, d) {\
	SQUASHFS_MEMSET(s, d, sizeof(squashfs_super_block));\
	SQUASHFS_SWAP((s)->s_magic, d, 0, 32);\
	SQUASHFS_SWAP((s)->inodes, d, 32, 32);\
	SQUASHFS_SWAP((s)->bytes_used, d, 64, 32);\
	SQUASHFS_SWAP((s)->uid_start, d, 96, 32);\
	SQUASHFS_SWAP((s)->guid_start, d, 128, 32);\
	SQUASHFS_SWAP((s)->inode_table_start, d, 160, 32);\
	SQUASHFS_SWAP((s)->directory_table_start, d, 192, 32);\
	SQUASHFS_SWAP((s)->s_major, d, 224, 16);\
	SQUASHFS_SWAP((s)->s_minor, d, 240, 16);\
	SQUASHFS_SWAP((s)->block_size_1, d, 256, 16);\
	SQUASHFS_SWAP((s)->block_log, d, 272, 16);\
	SQUASHFS_SWAP((s)->flags, d, 288, 8);\
	SQUASHFS_SWAP((s)->no_uids, d, 296, 8);\
	SQUASHFS_SWAP((s)->no_guids, d, 304, 8);\
	SQUASHFS_SWAP((s)->mkfs_time, d, 312, 32);\
	SQUASHFS_SWAP((s)->root_inode, d, 344, 64);\
	SQUASHFS_SWAP((s)->block_size, d, 408, 32);\
	SQUASHFS_SWAP((s)->fragments, d, 440, 32);\
	SQUASHFS_SWAP((s)->fragment_table_start, d, 472, 32);\
}

#define SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, n) {\
	SQUASHFS_MEMSET(s, d, n);\
	SQUASHFS_SWAP((s)->inode_type, d, 0, 4);\
	SQUASHFS_SWAP((s)->mode, d, 4, 12);\
	SQUASHFS_SWAP((s)->uid, d, 16, 8);\
	SQUASHFS_SWAP((s)->guid, d, 24, 8);\
}

#define SQUASHFS_SWAP_IPC_INODE_HEADER(s, d) SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_ipc_inode_header))

#define SQUASHFS_SWAP_DEV_INODE_HEADER(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_dev_inode_header));\
	SQUASHFS_SWAP((s)->rdev, d, 32, 16);\
}

#define SQUASHFS_SWAP_SYMLINK_INODE_HEADER(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_symlink_inode_header));\
	SQUASHFS_SWAP((s)->symlink_size, d, 32, 16);\
}

#define SQUASHFS_SWAP_REG_INODE_HEADER(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_reg_inode_header));\
	SQUASHFS_SWAP((s)->mtime, d, 32, 32);\
	SQUASHFS_SWAP((s)->start_block, d, 64, 32);\
	SQUASHFS_SWAP((s)->fragment, d, 96, 32);\
	SQUASHFS_SWAP((s)->offset, d, 128, 32);\
	SQUASHFS_SWAP((s)->file_size, d, 160, SQUASHFS_MAX_FILE_SIZE_LOG);\
}

#define SQUASHFS_SWAP_DIR_INODE_HEADER(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_dir_inode_header));\
	SQUASHFS_SWAP((s)->file_size, d, 32, 19);\
	SQUASHFS_SWAP((s)->offset, d, 51, 13);\
	SQUASHFS_SWAP((s)->mtime, d, 64, 32);\
	SQUASHFS_SWAP((s)->start_block, d, 96, 24);\
}

#define SQUASHFS_SWAP_LDIR_INODE_HEADER(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_ldir_inode_header));\
	SQUASHFS_SWAP((s)->file_size, d, 32, 27);\
	SQUASHFS_SWAP((s)->offset, d, 59, 13);\
	SQUASHFS_SWAP((s)->mtime, d, 72, 32);\
	SQUASHFS_SWAP((s)->start_block, d, 104, 24);\
	SQUASHFS_SWAP((s)->i_count, d, 128, 16);\
}

#define SQUASHFS_SWAP_DIR_INDEX(s, d) {\
	SQUASHFS_MEMSET(s, d, sizeof(squashfs_dir_index));\
	SQUASHFS_SWAP((s)->index, d, 0, 27);\
	SQUASHFS_SWAP((s)->start_block, d, 27, 29);\
	SQUASHFS_SWAP((s)->size, d, 56, 8);\
}

#define SQUASHFS_SWAP_DIR_HEADER(s, d) {\
	SQUASHFS_MEMSET(s, d, sizeof(squashfs_dir_header));\
	SQUASHFS_SWAP((s)->count, d, 0, 8);\
	SQUASHFS_SWAP((s)->start_block, d, 8, 24);\
}

#define SQUASHFS_SWAP_DIR_ENTRY(s, d) {\
	SQUASHFS_MEMSET(s, d, sizeof(squashfs_dir_entry));\
	SQUASHFS_SWAP((s)->offset, d, 0, 13);\
	SQUASHFS_SWAP((s)->type, d, 13, 3);\
	SQUASHFS_SWAP((s)->size, d, 16, 8);\
}

#define SQUASHFS_SWAP_FRAGMENT_ENTRY(s, d) {\
	SQUASHFS_MEMSET(s, d, sizeof(squashfs_fragment_entry));\
	SQUASHFS_SWAP((s)->start_block, d, 0, 32);\
	SQUASHFS_SWAP((s)->size, d, 32, 32);\
}

#define SQUASHFS_SWAP_SHORTS(s, d, n) {\
	int entry;\
	int bit_position;\
	SQUASHFS_MEMSET(s, d, n * 2);\
	for(entry = 0, bit_position = 0; entry < n; entry++, bit_position += 16)\
		SQUASHFS_SWAP(s[entry], d, bit_position, 16);\
}

#define SQUASHFS_SWAP_INTS(s, d, n) {\
	int entry;\
	int bit_position;\
	SQUASHFS_MEMSET(s, d, n * 4);\
	for(entry = 0, bit_position = 0; entry < n; entry++, bit_position += 32)\
		SQUASHFS_SWAP(s[entry], d, bit_position, 32);\
}

#define SQUASHFS_SWAP_DATA(s, d, n, bits) {\
	int entry;\
	int bit_position;\
	SQUASHFS_MEMSET(s, d, n * bits / 8);\
	for(entry = 0, bit_position = 0; entry < n; entry++, bit_position += bits)\
		SQUASHFS_SWAP(s[entry], d, bit_position, bits);\
}

#define SQUASHFS_SWAP_FRAGMENT_INDEXES(s, d, n) SQUASHFS_SWAP_INTS(s, d, n)

#ifdef SQUASHFS_1_0_COMPATIBILITY
typedef struct {
	unsigned int		inode_type:4;
	unsigned int		mode:12; /* protection */
	unsigned int		uid:4; /* index into uid table */
	unsigned int		guid:4; /* index into guid table */
} __attribute__ ((packed)) squashfs_base_inode_header_1;

typedef struct {
	unsigned int		inode_type:4;
	unsigned int		mode:12; /* protection */
	unsigned int		uid:4; /* index into uid table */
	unsigned int		guid:4; /* index into guid table */
	unsigned int		type:4;
	unsigned int		offset:4;
} __attribute__ ((packed)) squashfs_ipc_inode_header_1;

typedef struct {
	unsigned int		inode_type:4;
	unsigned int		mode:12; /* protection */
	unsigned int		uid:4; /* index into uid table */
	unsigned int		guid:4; /* index into guid table */
	unsigned short		rdev;
} __attribute__ ((packed)) squashfs_dev_inode_header_1;
	
typedef struct {
	unsigned int		inode_type:4;
	unsigned int		mode:12; /* protection */
	unsigned int		uid:4; /* index into uid table */
	unsigned int		guid:4; /* index into guid table */
	unsigned short		symlink_size;
	char			symlink[0];
} __attribute__ ((packed)) squashfs_symlink_inode_header_1;

typedef struct {
	unsigned int		inode_type:4;
	unsigned int		mode:12; /* protection */
	unsigned int		uid:4; /* index into uid table */
	unsigned int		guid:4; /* index into guid table */
	unsigned int		mtime;
	squashfs_block		start_block;
	unsigned int		file_size:SQUASHFS_MAX_FILE_SIZE_LOG;
	unsigned short		block_list[0];
} __attribute__ ((packed)) squashfs_reg_inode_header_1;

typedef struct {
	unsigned int		inode_type:4;
	unsigned int		mode:12; /* protection */
	unsigned int		uid:4; /* index into uid table */
	unsigned int		guid:4; /* index into guid table */
	unsigned int		file_size:19;
	unsigned int		offset:13;
	unsigned int		mtime;
	unsigned int		start_block:24;
} __attribute__  ((packed)) squashfs_dir_inode_header_1;

#define SQUASHFS_SWAP_BASE_INODE_HEADER_1(s, d, n) {\
	SQUASHFS_MEMSET(s, d, n);\
	SQUASHFS_SWAP((s)->inode_type, d, 0, 4);\
	SQUASHFS_SWAP((s)->mode, d, 4, 12);\
	SQUASHFS_SWAP((s)->uid, d, 16, 4);\
	SQUASHFS_SWAP((s)->guid, d, 20, 4);\
}

#define SQUASHFS_SWAP_IPC_INODE_HEADER_1(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER_1(s, d, sizeof(squashfs_ipc_inode_header_1));\
	SQUASHFS_SWAP((s)->type, d, 24, 4);\
	SQUASHFS_SWAP((s)->offset, d, 28, 4);\
}

#define SQUASHFS_SWAP_DEV_INODE_HEADER_1(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER_1(s, d, sizeof(squashfs_dev_inode_header_1));\
	SQUASHFS_SWAP((s)->rdev, d, 24, 16);\
}

#define SQUASHFS_SWAP_SYMLINK_INODE_HEADER_1(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_symlink_inode_header_1));\
	SQUASHFS_SWAP((s)->symlink_size, d, 24, 16);\
}

#define SQUASHFS_SWAP_REG_INODE_HEADER_1(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_reg_inode_header_1));\
	SQUASHFS_SWAP((s)->mtime, d, 24, 32);\
	SQUASHFS_SWAP((s)->start_block, d, 56, 32);\
	SQUASHFS_SWAP((s)->file_size, d, 88, SQUASHFS_MAX_FILE_SIZE_LOG);\
}

#define SQUASHFS_SWAP_DIR_INODE_HEADER_1(s, d) {\
	SQUASHFS_SWAP_BASE_INODE_HEADER(s, d, sizeof(squashfs_dir_inode_header_1));\
	SQUASHFS_SWAP((s)->file_size, d, 24, 19);\
	SQUASHFS_SWAP((s)->offset, d, 43, 13);\
	SQUASHFS_SWAP((s)->mtime, d, 56, 32);\
	SQUASHFS_SWAP((s)->start_block, d, 88, 24);\
}
#endif

#ifdef __KERNEL__
/*
 * macros used to swap each structure entry, taking into account
 * bitfields and different bitfield placing conventions on differing architectures
 */
#include <asm/byteorder.h>
#ifdef __BIG_ENDIAN
	/* convert from little endian to big endian */
#define SQUASHFS_SWAP(value, p, pos, tbits) _SQUASHFS_SWAP(value, p, pos, tbits, b_pos)
#else
	/* convert from big endian to little endian */ 
#define SQUASHFS_SWAP(value, p, pos, tbits) _SQUASHFS_SWAP(value, p, pos, tbits, 64 - tbits - b_pos)
#endif

#define _SQUASHFS_SWAP(value, p, pos, tbits, SHIFT) {\
	int bits;\
	int b_pos = pos % 8;\
	unsigned long long val = 0;\
	unsigned char *s = (unsigned char *)p + (pos / 8);\
	unsigned char *d = ((unsigned char *) &val) + 7;\
	for(bits = 0; bits < (tbits + b_pos); bits += 8) \
		*d-- = *s++;\
	value = (val >> (SHIFT))/* & ((1 << tbits) - 1)*/;\
}
#define SQUASHFS_MEMSET(s, d, n)	memset(s, 0, n);
#endif
#endif