windows的磁盘操作之三——获取和删除磁盘分区信息

上一节中介绍了如何初始化一块空白的磁盘，并创建分区。那么对于一块已存在分区的磁盘，我们如何获得其分区信息，如何删除其分区信息呢？本节对这两类操作进行讨论。

获得磁盘分区信息的代码如下。

/******************************************************************************

* Function: get the disk's drive layout infomation

* input: disk, disk name

* output: drive layout info

* return: Succeed, 0

* Fail, -1

******************************************************************************/

DWORD GetDiskDriveLayout(const CHAR *disk, DRIVE_LAYOUT_INFORMATION_EX *driveLayout)

{

HANDLE hDevice; // handle to the drive to be examined

BOOL result; // results flag

DWORD readed; // discard results

hDevice = CreateFile(

disk, // drive to open

GENERIC_READ | GENERIC_WRITE, // access to the drive

FILE_SHARE_READ | FILE_SHARE_WRITE, //share mode

NULL, // default security attributes

OPEN_EXISTING, // disposition

0, // file attributes

NULL // do not copy file attribute

);

if (hDevice == INVALID_HANDLE_VALUE) // cannot open the drive

{

fprintf(stderr, "CreateFile() Error: %ld\n", GetLastError());

return DWORD(-1);

}

result = DeviceIoControl(

hDevice, // handle to device

IOCTL_DISK_GET_DRIVE_LAYOUT_EX, // dwIoControlCode

NULL, // lpInBuffer

0, // nInBufferSize

driveLayout, // output buffer

sizeof(*driveLayout), // size of output buffer

&readed, // number of bytes returned

NULL // OVERLAPPED structure

);

if (!result)

{

fprintf(stderr, "IOCTL_DISK_GET_DRIVE_LAYOUT_EX Error: %ld\n", GetLastError());

(void)CloseHandle(hDevice);

return DWORD(-1);

}

(void)CloseHandle(hDevice);

return 0;

}

如果你已对上一节中创建分区的代码http://cutebunny.blog.51cto.com/301216/624052 有了比较深刻的了解，那么这段代码就非常简单了。程序执行流程为：

1． 根据disk名称调用CreateFile打开设备句柄。

2． 调用操作码为IOCTL_DISK_GET_DRIVE_LAYOUT_EX的DeviceIoControl函数获取分区信息。返回的信息存储在DRIVE_LAYOUT_INFORMATION_EX
*driveLayout中。本例中我们只考虑了一个分区的情况，如果有多个分区，适当调整DeviceIoControl函数中的nOutBufferSize参数即可。

3． 解析*driveLayout即可获得分区信息。

删除磁盘分区信息的代码如下，

/******************************************************************************

* Function: delete the partition layout of the disk

* input: disk, disk name

* output: N/A

* return: Succeed, 0

* Fail, -1

******************************************************************************/

DWORD DestroyDisk(DWORD disk)

{

HANDLE hDevice; // handle to the drive to be examined

BOOL result; // results flag

DWORD readed; // discard results

CHAR diskPath[DISK_PATH_LEN];

sprintf(diskPath, "\\\\.\\PhysicalDrive%d", disk);

hDevice = CreateFile(

diskPath, // drive to open

GENERIC_READ | GENERIC_WRITE, // access to the drive

FILE_SHARE_READ | FILE_SHARE_WRITE, //share mode

NULL, // default security attributes

OPEN_EXISTING, // disposition

0, // file attributes

NULL // do not copy file attribute

);

if (hDevice == INVALID_HANDLE_VALUE) // cannot open the drive

{

fprintf(stderr, "CreateFile() Error: %ld\n", GetLastError());

return DWORD(-1);

}

result = DeviceIoControl(

hDevice, // handle to device

IOCTL_DISK_DELETE_DRIVE_LAYOUT, // dwIoControlCode

NULL, // lpInBuffer

0, // nInBufferSize

NULL, // lpOutBuffer

0, // nOutBufferSize

&readed, // number of bytes returned

NULL // OVERLAPPED structure

);

if (!result)

{

//fprintf(stderr, "IOCTL_DISK_DELETE_DRIVE_LAYOUT Error: %ld\n", GetLastError());

(void)CloseHandle(hDevice);

return DWORD(-1);

}

//fresh the partition table

result = DeviceIoControl(

hDevice,

IOCTL_DISK_UPDATE_PROPERTIES,

NULL,

0,

NULL,

0,

&readed,

NULL

);

if (!result)

{

fprintf(stderr, "IOCTL_DISK_UPDATE_PROPERTIES Error: %ld\n", GetLastError());

(void)CloseHandle(hDevice);

return DWORD(-1);

}

(void)CloseHandle(hDevice);

return 0;

}

参数DWORD disk为物理驱动器号。函数执行流程为：

1． 根据驱动器号生成设备名称。

2． 调用CreateFile打开设备并获得设备句柄。

3． 调用操作码为IOCTL_DISK_DELETE_DRIVE_LAYOUT的DeviceIoControl函数删除分区表。

4． 刷新分区表。

调用DestroyDisk后的磁盘在windows磁盘管理中的状态为