logfile.h

LINUX下读写NTFS分区的工具。 已经集成了通过LIBCONV库支持中文的代码。

/* 22*/	le16 client_array_offset;/* Offset from the start of this record to
				   the first log client record if versions are
				   matched.  When creating, set this to be
				   after this restart area structure, aligned
				   to 8-bytes boundary.  If the versions do not
				   match, this is ignored and the offset is
				   assumed to be (sizeof(RESTART_AREA) + 7) &
				   ~7, i.e. rounded up to first 8-byte
				   boundary.  Either way, client_array_offset
				   has to be aligned to an 8-byte boundary.
				   Also, restart_area_offset +
				   client_array_offset has to be <= 510.
				   Finally, client_array_offset + (log_clients
				   * sizeof(log client record)) has to be <=
				   system_page_size.  On Win2k and presumably
				   earlier, this is 0x30, i.e. immediately
				   following this record.  On WinXP and
				   presumably later, this is 0x40, i.e. there
				   are 16 extra bytes between this record and
				   the client array.  This probably means that
				   the RESTART_AREA record is actually bigger
				   in WinXP and later. */
/* 24*/	sle64 file_size;	/* Usable byte size of the log file.  If the
				   restart_area_offset + the offset of the
				   file_size are > 510 then corruption has
				   occurred.  This is the very first check when
				   starting with the restart_area as if it
				   fails it means that some of the above values
				   will be corrupted by the multi sector
				   transfer protection.  The file_size has to
				   be rounded down to be a multiple of the
				   log_page_size in the RESTART_PAGE_HEADER and
				   then it has to be at least big enough to
				   store the two restart pages and 48 (0x30)
				   log record pages. */
/* 32*/	le32 last_lsn_data_length;/* Length of data of last LSN, not including
				   the log record header.  On create set to
				   0. */
/* 36*/	le16 log_record_header_length;/* Byte size of the log record header.
				   If the version matches then check that the
				   value of log_record_header_length is a
				   multiple of 8, i.e.
				   (log_record_header_length + 7) & ~7 ==
				   log_record_header_length.  When creating set
				   it to sizeof(LOG_RECORD_HEADER), aligned to
				   8 bytes. */
/* 38*/	le16 log_page_data_offset;/* Offset to the start of data in a log record
				   page.  Must be a multiple of 8.  On create
				   set it to immediately after the update
				   sequence array of the log record page. */
/* 40*/	le32 restart_log_open_count;/* A counter that gets incremented every
				   time the logfile is restarted which happens
				   at mount time when the logfile is opened.
				   When creating set to a random value.  Win2k
				   sets it to the low 32 bits of the current
				   system time in NTFS format (see time.h). */
/* 44*/	le32 reserved;		/* Reserved/alignment to 8-byte boundary. */
/* sizeof() = 48 (0x30) bytes */
} __attribute__((__packed__)) RESTART_AREA;

/**
 * struct LOG_CLIENT_RECORD - Log client record.
 *
 * The offset of this record is found by adding the offset of the
 * RESTART_AREA to the client_array_offset value found in it.
 */
typedef struct {
/*Ofs*/
/*  0*/	leLSN oldest_lsn;	/* Oldest LSN needed by this client.  On create
				   set to 0. */
/*  8*/	leLSN client_restart_lsn;/* LSN at which this client needs to restart
				   the volume, i.e. the current position within
				   the log file.  At present, if clean this
				   should = current_lsn in restart area but it
				   probably also = current_lsn when dirty most
				   of the time.  At create set to 0. */
/* 16*/	le16 prev_client;	/* The offset to the previous log client record
				   in the array of log client records.
				   LOGFILE_NO_CLIENT means there is no previous
				   client record, i.e. this is the first one.
				   This is always LOGFILE_NO_CLIENT. */
/* 18*/	le16 next_client;	/* The offset to the next log client record in
				   the array of log client records.
				   LOGFILE_NO_CLIENT means there are no next
				   client records, i.e. this is the last one.
				   This is always LOGFILE_NO_CLIENT. */
/* 20*/	le16 seq_number;	/* On Win2k and presumably earlier, this is set
				   to zero every time the logfile is restarted
				   and it is incremented when the logfile is
				   closed at dismount time.  Thus it is 0 when
				   dirty and 1 when clean.  On WinXP and
				   presumably later, this is always 0. */
/* 22*/	u8 reserved[6];		/* Reserved/alignment. */
/* 28*/	le32 client_name_length;/* Length of client name in bytes.  Should
				   always be 8. */
/* 32*/	ntfschar client_name[64];/* Name of the client in Unicode.  Should
				   always be "NTFS" with the remaining bytes
				   set to 0. */
/* sizeof() = 160 (0xa0) bytes */
} __attribute__((__packed__)) LOG_CLIENT_RECORD;

/**
 * struct RECORD_PAGE_HEADER - Log page record page header.
 *
 * Each log page begins with this header and is followed by several LOG_RECORD
 * structures, starting at offset 0x40 (the size of this structure and the
 * following update sequence array and then aligned to 8 byte boundary, but is
 * this specified anywhere?).
 */
typedef struct {
/*  0	NTFS_RECORD; -- Unfolded here as gcc doesn't like unnamed structs. */
	NTFS_RECORD_TYPES magic;/* Usually the magic is "RCRD". */
	u16 usa_ofs;		/* See NTFS_RECORD definition in layout.h.
				   When creating, set this to be immediately
				   after this header structure (without any
				   alignment). */
	u16 usa_count;		/* See NTFS_RECORD definition in layout.h. */

	union {
		LSN last_lsn;
		s64 file_offset;
	} __attribute__((__packed__)) copy;
	u32 flags;
	u16 page_count;
	u16 page_position;
	union {
		struct {
			u16 next_record_offset;
			u8 reserved[6];
			LSN last_end_lsn;
		} __attribute__((__packed__)) packed;
	} __attribute__((__packed__)) header;
} __attribute__((__packed__)) RECORD_PAGE_HEADER;

/**
 * enum LOG_RECORD_FLAGS - Possible 16-bit flags for log records.
 *
 * (Or is it log record pages?)
 */
typedef enum {
	LOG_RECORD_MULTI_PAGE = const_cpu_to_le16(0x0001),	/* ??? */
	LOG_RECORD_SIZE_PLACE_HOLDER = 0xffff,
		/* This has nothing to do with the log record. It is only so
		   gcc knows to make the flags 16-bit. */
} __attribute__((__packed__)) LOG_RECORD_FLAGS;

/**
 * struct LOG_CLIENT_ID - The log client id structure identifying a log client.
 */
typedef struct {
	u16 seq_number;
	u16 client_index;
} __attribute__((__packed__)) LOG_CLIENT_ID;

/**
 * struct LOG_RECORD - Log record header.
 *
 * Each log record seems to have a constant size of 0x70 bytes.
 */
typedef struct {
	LSN this_lsn;
	LSN client_previous_lsn;
	LSN client_undo_next_lsn;
	u32 client_data_length;
	LOG_CLIENT_ID client_id;
	u32 record_type;
	u32 transaction_id;
	u16 flags;
	u16 reserved_or_alignment[3];
/* Now are at ofs 0x30 into struct. */
	u16 redo_operation;
	u16 undo_operation;
	u16 redo_offset;
	u16 redo_length;
	u16 undo_offset;
	u16 undo_length;
	u16 target_attribute;
	u16 lcns_to_follow;		   /* Number of lcn_list entries
					      following this entry. */
/* Now at ofs 0x40. */
	u16 record_offset;
	u16 attribute_offset;
	u32 alignment_or_reserved;
	VCN target_vcn;
/* Now at ofs 0x50. */
	struct {			   /* Only present if lcns_to_follow
					      is not 0. */
		LCN lcn;
	} __attribute__((__packed__)) lcn_list[0];
} __attribute__((__packed__)) LOG_RECORD;

extern BOOL ntfs_check_logfile(ntfs_attr *log_na, RESTART_PAGE_HEADER **rp);
extern BOOL ntfs_is_logfile_clean(ntfs_attr *log_na, RESTART_PAGE_HEADER *rp);
extern int ntfs_empty_logfile(ntfs_attr *na);

#endif /* defined _NTFS_LOGFILE_H */