读取磁盘MBR及分区信息

主要是磁盘的底层操作。明白了道理，就知道一些磁盘工具其实并没那么神秘。

用debug程序读取磁盘 MBR

-a 100 
mov ax, 0201   ; AH=02 代表“读”, (AL=要读的扇区数)
mov bx, 0200   ; 运行结果放在内存地址 0200 处 
mov cx, 1      ;
mov dx, 80     ; (DH=磁头, DL=0、1软盘，80、81硬盘)  80 代表第一硬盘 
int 13         ; 调用磁盘中断 
int 20         ; 结束程序 
-g =100        ; 从 100 处开始运行程序 
-d 200         ; 显示主引导记录 

Windows 下用 C/C++ 程序读取 MBR及分区信息

在Windows上Mingw 环境下编译通过。

#include <stdio.h>
#include <windows.h>

// 一个扇区可能的字节数为128×2n (n=0,1,2,3)。大多情况下，取n=2，为512字节
const static int DISK_SECTOR_SIZE = 512;

int read_mbr(const char *devname){
  char buffer[DISK_SECTOR_SIZE];  

  HANDLE hDev = CreateFile(devname, GENERIC_READ,   
                  FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);  
  if (hDev == INVALID_HANDLE_VALUE){  
      printf("Open %s FAIL.\n", devname);  
      exit(0);  
  }  
  printf("Open %s PASS.\n", devname);  

  //SetFilePointer(hDev, 0, 0, FILE_BEGIN);  
  int  cb;  
  BOOL ret = (BOOL) ReadFile(hDev, buffer, 512, (DWORD*) &cb, NULL);  
  CloseHandle(hDev);  
  if ( 0 == ret || DISK_SECTOR_SIZE != cb)  {  
     printf("Error: read error! ret=%d #bytes=%d\n", ret, cb);  
     exit(0);  
  }  

  printf("#bytes =  %d\n", cb);  
  printf("%10s 0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f \n", " ");  
  for (int i=0 ;i<32 ;i++ ){  
      printf("%.8Xh: ", i);  
      for (int j=0 ;j<16 ;j++ ){
          printf("%.2x ", buffer[i*16+j] & 0xFF);  
      }  
      printf("\n");  
  }  

  printf("====MBR Partition Entry====\n");
  for(int i=0x01be; i<0x01FE; i+=16){
      for (int j=0 ;j<16 ;j++ ){  
          printf("%02x ", buffer[i + j] & 0xFF);  
      }  
      int d_status   = buffer[i+0] & 0xff;
      int d_format   = buffer[i+4] & 0xff;

      int s_head     = buffer[i+1] & 0xff;
      int s_sector   = buffer[i+2] & 0x3f;
      int s_cylinder = (((buffer[i+2] & 0xff) >> 6) << 8) + (buffer[i+3] & 0xff);

      int e_head     = buffer[i+5] & 0xff;
      int e_sector   = buffer[i+6] & 0x3f;
      int e_cylinder = (((buffer[i+6] & 0xff >> 6)) << 8) + (buffer[i+7] & 0xff);

      unsigned int sector_offset = *((unsigned int*)(buffer+i+8));
      unsigned int sector_size   = *((unsigned int*)(buffer+i+12));
      printf("\n");

      long d_mbytes = sector_size/1024*DISK_SECTOR_SIZE/1024/1024;

      printf("%02x | %02x | (%d, %d, %d) (%d, %d, %d) | %d+%d = %i GB\n", 
	      d_status, d_format,
	      s_cylinder, s_head, s_sector, e_cylinder, e_head, e_sector,
	      sector_offset, sector_size,  d_mbytes);
      printf("\n");
  }
   
  return 0;
}

int main(int argc, char *argv[]){  
    //-- read_mbr("\\\\.\\C:");
    read_mbr("\\\\.\\PhysicalDrive0");
    return 0;
}

/****** Demo Output ******
====MBR Partition Entry====
80 01 01 00 07 fe ff ff 3f 00 00 00 82 37 f9 0d 
80 | 07 | (0, 1, 1) (1023, 254, 63) | 63+234436482 = 111 GB
*/

相关资源

• 磁盘的分区和引导