// VHD Footer structure
typedef struct {u_char        cookie[MT_CKS];    // Cookieu_int32_t    features;    // Featuresu_int32_t    ffversion;    // File format versionu_int64_t    dataoffset;    // Data offsetu_int32_t    timestamp;    // Timestampu_int32_t    creatorapp;    // Creator applicationu_int32_t    creatorver;    // Creator versionu_int32_t    creatorhos;    // Creator host OSu_int64_t    origsize;    // Original sizeu_int64_t    currsize;    // Current sizeu_int32_t    diskgeom;    // Disk geometryu_int32_t    disktype;    // Disk typeu_int32_t    checksum;    // Checksumu_char        uniqueid[16];    // Unique IDu_char        savedst;    // Saved stateu_char        reserved[427];    // Reserved
}__attribute__((__packed__)) vhd_footer_t;

int  count= 要lseek的数字/(65535*65535);
for( int i = 0;i<count;i++ )
lseek( 65535*65535 );
lseek( 要lseek的数字%(65535*65535) )

// VHD Dynamic Disk Header structure
typedef struct {u_char        cookie[MT_CKS];    // Cookieu_int64_t    dataoffset;    // Data offsetu_int64_t    tableoffset;    // Table offsetu_int32_t    headerversion;    // Header versionu_int32_t    maxtabentries;    // Max table entriesu_int32_t    blocksize;    // Block sizeu_int32_t    checksum;    // Checksumu_char        parentuuid[16];    // Parent Unique IDu_int32_t    parentts;    // Parent Timestampu_char        reserved1[4];    // Reservedu_char        parentname[512];// Parent Unicode Nameu_char        parentloc1[24];    // Parent Locator Entry 1u_char        parentloc2[24];    // Parent Locator Entry 2u_char        parentloc3[24];    // Parent Locator Entry 3u_char        parentloc4[24];    // Parent Locator Entry 4u_char        parentloc5[24];    // Parent Locator Entry 5u_char        parentloc6[24];    // Parent Locator Entry 6u_char        parentloc7[24];    // Parent Locator Entry 7u_char        parentloc8[24];    // Parent Locator Entry 8u_char        reserved2[256];    // Reserved
}__attribute__((__packed__)) vhd_ddhdr_t;

/*
* 功能：将磁盘地址转到vhd地址位置获取到对应扇区信息
* offset偏移扇区数,size读取长度
*/
u_char * Address2VHD(u_int64_t offset,int size)
{int blk_index = offset/(blk_size / MT_SECS);int sc_index = offset % (blk_size / MT_SECS);u_char sc[MT_SECS*size];int lk = lseek(vhdfd,SwapInt32(batmap[blk_index])*(u_int32_t)MT_SECS + 512 + sc_index*(u_int32_t)MT_SECS,SEEK_SET);if(lk < 0 ){perror("lseek");}else{read(vhdfd,sc,MT_SECS*size);return sc;}
}

#pragma pack(1)/*一个分区表的表头信息*/
typedef struct DPT_Header
{u_char State;   //分区状态, 0 = 未激活,0x80 = 激活u_char StartHead;  //分区起始磁头号u_int16_t StartSC;  //分区起始扇区和柱面号,低字节（低6位为扇区号,高2位为柱面号的第9,10位）,高字节（柱面号的低8位）,考虑到字节序问题可能不一样u_char Type;   //分区类型,00 表示此项未用,其他标号代表各种系统u_char EndHead;  //分区结束磁头号u_int16_t EndSC;   //分区结束扇区和柱面号,定义同前u_int32_t Relative;  //在线性寻址方式下的分区相对扇区地址(对于基本分区即为绝对地址),从0开始的扇区数u_int32_t Sectors;  //分区大小 (总扇区数)
} DPT_Header;//引导区512u_char结构
typedef struct _MBR_SECTOR
{u_char BootCode[440];//启动记录440 u_charu_int32_t DiskSignature;//磁盘签名 4字节//u_int16_t blank1;u_int16_t NoneDisk;//二个字节DPT_Header Partition[4];//分区表结构64 u_charu_int16_t Signature;//结束标志2 u_char 55 AA//u_int16_t blank2;
} MBR_SECTOR, *PMBR_SECTOR;
#pragma pack()

typedef struct _PACKED_BOOT_SECTOR {UCHAR Jump[3];                                                  //  offset = 0x000UCHAR Oem[8];                                                   //  offset = 0x003BIOS_PARAMETER_BLOCK PackedBpb;                          //  offset = 0x00BUCHAR Unused[4];                                                //  offset = 0x024LONGLONG NumberSectors;                                         //  offset = 0x028LCN MftStartLcn;                                                //  offset = 0x030LCN Mft2StartLcn;                                               //  offset = 0x038CHAR ClustersPerFileRecordSegment;                              //  offset = 0x040UCHAR Reserved0[3];CHAR DefaultClustersPerIndexAllocationBuffer;                   //  offset = 0x044UCHAR Reserved1[3];LONGLONG SerialNumber;                                          //  offset = 0x048ULONG Checksum;                                                 //  offset = 0x050UCHAR BootStrap[0x200-0x044];                                   //  offset = 0x054

} PACKED_BOOT_SECTOR;   

typedef struct BIOS_PARAMETER_BLOCK {USHORT BytesPerSector;UCHAR  SectorsPerCluster;USHORT ReservedSectors;UCHAR  Fats;USHORT RootEntries;USHORT Sectors;UCHAR  Media;USHORT SectorsPerFat;USHORT SectorsPerTrack;USHORT Heads;ULONG  HiddenSectors;ULONG  LargeSectors;} BIOS_PARAMETER_BLOCK;