windows的磁盘操作之九——区分本地磁盘与移动硬盘

http://cutebunny.blog.51cto.com/301216/674443

最近碰到了个新问题，记录下来作为windows的磁盘操作那个系列的续篇吧。

一些时候我们的程序需要区分本地存储设备和USB存储设备。在网上搜一搜一般会找到一个最直接的API，GetDriveType，其原型为

UINT GetDriveType(LPCTSTR lpRootPathName)

参数lpRootPathName是存储设备的根目录，例如C:\，返回值即为设备类型。

Return code	Description
DRIVE_REMOVABLE	The drive has removable media; for example, a floppy drive, thumb drive, or flash card reader.
DRIVE_FIXED	The drive has fixed media; for example, a hard drive or flash drive.

或者采用一种稍微复杂一点的方法，使用我们第一节
http://cutebunny.blog.51cto.com/301216/624027中介绍的GetDriveGeometry()函数，其输出参数DISK_GEOMETRY *pdg中的MediaType字段代表设备类型。

 

typedef enum _MEDIA_TYPE
{
  RemovableMedia,
  FixedMedia
} MEDIA_TYPE;

这两个方法看似能方便快捷的解决我们的需求，但事实上当你使用GetDriveType()去获取一块移动硬盘的类型时，
程序会坑爹的告诉你这块移动硬盘的类型是DRIVE_FIXED，根本无法与本地磁盘区分开来。
GetDriveGeometry()函数的结果也是如此。

事实上，上述方法只对小容量的U盘有效，会返回给你DRIVE_REMOVABLE的结果；
而对移动硬盘甚至是一块稍大容量的U盘（比如我有一块格式化为FAT32格式的4G U盘），就无能为力了。

 

所以，我们必须采用别的思路了，这里我介绍一种通过查看总线类型来区分本地磁盘和USB磁盘的方法。
当然，其基础还是我们那万能的DeviceIoControl，不过这次的控制码为IOCTL_STORAGE_QUERY_PROPERTY。
同时对应的输入参数为STORAGE_PROPERTY_QUERY结构，输出参数为STORAGE_DEVICE_DESCRIPTOR结构体。

typedef struct _STORAGE_PROPERTY_QUERY {
  STORAGE_PROPERTY_ID  PropertyId;
  STORAGE_QUERY_TYPE  QueryType;
  UCHAR  AdditionalParameters[];
} STORAGE_PROPERTY_QUERY, *PSTORAGE_PROPERTY_QUERY;

调用时需设置输入参数中的字段

PropertyId = StorageDeviceProperty;

QueryType = PropertyStandardQuery;

以表明我们要查询一个device descriptor，也就是说，只有指定这种类型，
输出参数才会得到STORAGE_DEVICE_DESCRIPTOR类型数据。

 

typedef struct _STORAGE_DEVICE_DESCRIPTOR {
  ULONG  Version;
  ULONG  Size;
  UCHAR  DeviceType;
  UCHAR  DeviceTypeModifier;
  BOOLEAN  RemovableMedia;
  BOOLEAN  CommandQueueing;
  ULONG  VendorIdOffset;
  ULONG  ProductIdOffset;
  ULONG  ProductRevisionOffset;
  ULONG  SerialNumberOffset;
  STORAGE_BUS_TYPE  BusType;
  ULONG  RawPropertiesLength;
  UCHAR  RawDeviceProperties[];
} STORAGE_DEVICE_DESCRIPTOR, *PSTORAGE_DEVICE_DESCRIPTOR;

typedef enum _STORAGE_BUS_TYPE {
  BusTypeUnknown = 0x00,
  BusTypeScsi,
  BusTypeAtapi,
  BusTypeAta,
  BusType1394,
  BusTypeSsa,
  BusTypeFibre,
  BusTypeUsb,
  BusTypeRAID,
  BusTypeiScsi,
  BusTypeSas,
  BusTypeSata,
  BusTypeSd,
  BusTypeMmc,
  BusTypeMax,
  BusTypeMaxReserved = 0x7F
} STORAGE_BUS_TYPE, *PSTORAGE_BUS_TYPE;

明白了吧，如果总线类型为BusTypeUsb，就是找到了我们的USB移动硬盘了。

但此时还需要解决一个问题，STORAGE_DEVICE_DESCRIPTOR可以理解为一个变长缓冲区，
最后一个字段RawDeviceProperties[1]是可以动态扩展的（windows API经常有这种情况），
那么函数DeviceIoControl()中的参数nOutBufferSize应该填多少呢？
这时我们需要借助另一个数据结构STORAGE_DESCRIPTOR_HEADER，
在我们不知道device descriptor实际需要多大的缓冲区时，
可以先把STORAGE_DESCRIPTOR_HEADER作为输出参数以获得device descriptor的缓冲区大小，
其大小被存入header的size字段中。

typedef struct _STORAGE_DESCRIPTOR_HEADER {
  ULONG  Version;
  ULONG  Size;
} STORAGE_DESCRIPTOR_HEADER, *PSTORAGE_DESCRIPTOR_HEADER;

/******************************************************************************
 * Function: get the bus type of an disk
 * input: drive name (c:)
 * output: bus type
 * return: Succeed, 0
 *         Fail, -1
 ******************************************************************************/
DWORD GetDriveTypeByBus( const CHAR *drive, WORD *type )
{
  HANDLE hDevice;               // handle to the drive to be examined
  BOOL result;                 // results flag
  DWORD readed;                   // discard results
 
  STORAGE_DESCRIPTOR_HEADER *pDevDescHeader;
  STORAGE_DEVICE_DESCRIPTOR *pDevDesc;
  DWORD devDescLength;
  STORAGE_PROPERTY_QUERY query;
 
  hDevice = CreateFile( drive, // 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
    ,                // 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( - );
  }
 
  query.PropertyId = StorageDeviceProperty;
  query.QueryType = PropertyStandardQuery;
 
  pDevDescHeader = (STORAGE_DESCRIPTOR_HEADER *) malloc(
    sizeof(STORAGE_DESCRIPTOR_HEADER) );
  if ( NULL == pDevDescHeader )
  {
    return (DWORD) -;
  }
 
  result = DeviceIoControl( hDevice,     // device to be queried
    IOCTL_STORAGE_QUERY_PROPERTY,     // operation to perform
    &query, sizeof query,               // no input buffer
    pDevDescHeader, sizeof(STORAGE_DESCRIPTOR_HEADER),     // output buffer
    &readed,                 // # bytes returned
    NULL );      // synchronous I/O
  if ( !result )        //fail
  {
    fprintf( stderr, "IOCTL_STORAGE_QUERY_PROPERTY Error: %ld\n",
      GetLastError( ) );
    free( pDevDescHeader );
    (void) CloseHandle( hDevice );
    return DWORD( - );
  }
 
  devDescLength = pDevDescHeader->Size;
  pDevDesc = (STORAGE_DEVICE_DESCRIPTOR *) malloc( devDescLength );
  if ( NULL == pDevDesc )
  {
    free( pDevDescHeader );
    return (DWORD) -;
  }
 
  result = DeviceIoControl( hDevice,     // device to be queried
    IOCTL_STORAGE_QUERY_PROPERTY,     // operation to perform
    &query, sizeof query,               // no input buffer
    pDevDesc, devDescLength,     // output buffer
    &readed,                 // # bytes returned
    NULL );      // synchronous I/O
  if ( !result )        //fail
  {
    fprintf( stderr, "IOCTL_STORAGE_QUERY_PROPERTY Error: %ld\n",
      GetLastError( ) );
    free( pDevDescHeader );
    free( pDevDesc );
    (void) CloseHandle( hDevice );
    return DWORD( - );
  }
 
  //printf("%d\n", pDevDesc->BusType);
  *type = (WORD) pDevDesc->BusType;
  free( pDevDescHeader );
  free( pDevDesc );
 
  (void) CloseHandle( hDevice );
  return ;
}

代码说明：

1． 调用CreateFile打开并获得设备句柄。

2． 在输入参数STORAGE_PROPERTY_QUERY query中指定查询类型。

3． 以STORAGE_DESCRIPTOR_HEADER *pDevDescHeader为输出参数，
调用操作码为IOCTL_STORAGE_QUERY_PROPERTY的DeviceIoControl函数获得输出缓冲区大小。

4． 按3中获得的缓冲区大小为STORAGE_DEVICE_DESCRIPTOR *pDevDesc分配空间，
以pDevDesc为输出参数，调用操作码为IOCTL_STORAGE_QUERY_PROPERTY的
DeviceIoControl函数获得device descriptor。

5． 从device descriptor中获得BusType。

 

BOOL
WINAPI
DeviceIoControl(
     _In_        (HANDLE)       hDevice,               // handle to a partition
     _In_        (DWORD) IOCTL_STORAGE_QUERY_PROPERTY, // dwIoControlCode
     _In_        (LPVOID)       lpInBuffer,            // input buffer - STORAGE_PROPERTY_QUERY structure
     _In_        (DWORD)        nInBufferSize,         // size of input buffer
     _Out_opt_   (LPVOID)       lpOutBuffer,           // output buffer - see Remarks
     _In_        (DWORD)        nOutBufferSize,        // size of output buffer
     _Out_opt_   (LPDWORD)      lpBytesReturned,       // number of bytes returned
     _Inout_opt_ (LPOVERLAPPED) lpOverlapped );        // OVERLAPPED structure

Parameters

hDevice

A handle to the disk device from which partition information is retrieved. To retrieve a device handle, call the CreateFile function.

dwIoControlCode

The control code for the operation. Use IOCTL_STORAGE_QUERY_PROPERTY for this operation.

lpInBuffer

A pointer to a buffer that contains a STORAGE_PROPERTY_QUERY data structure that specifies the details about the query. Device properties must be retrieved only from a device; attempting to retrieve device properties from an adapter will cause an error.

nInBufferSize

The size of the input buffer, in bytes. It must be large enough to contain aSTORAGE_PROPERTY_QUERY data structure.

lpOutBuffer

An optional pointer to a buffer that receives a structure that starts with the same fields as a STORAGE_DESCRIPTOR_HEADER data structure. For more information on the specific structures returned see the Remarks section.

nOutBufferSize

The size of the output buffer, in bytes. It can be zero to determine whether a property exists without retrieving its data. To do that, set this parameter to zero (0) and the QueryType member of the STORAGE_PROPERTY_QUERY input structure to PropertyExistsQuery (1). If the call to DeviceIoControl returns a nonzero value then the property exists.

lpBytesReturned

A pointer to a variable that receives the size of the data stored in the output buffer, in bytes.

If the output buffer is too small, the call fails, GetLastError returnsERROR_INSUFFICIENT_BUFFER, and lpBytesReturned is zero.

If lpOverlapped is NULL, lpBytesReturned cannot be NULL. Even when an operation returns no output data and lpOutBuffer is NULL, DeviceIoControl makes use oflpBytesReturned. After such an operation, the value of lpBytesReturned is meaningless.

If lpOverlapped is not NULL, lpBytesReturned can be NULL. If this parameter is not NULL and the operation returns data, lpBytesReturned is meaningless until the overlapped operation has completed. To retrieve the number of bytes returned, call GetOverlappedResult. If hDevice is associated with an I/O completion port, you can retrieve the number of bytes returned by callingGetQueuedCompletionStatus.

lpOverlapped

A pointer to an OVERLAPPED structure.

If hDevice was opened without specifying FILE_FLAG_OVERLAPPED, lpOverlapped is ignored.

If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, the operation is performed as an overlapped (asynchronous) operation. In this case, lpOverlappedmust point to a valid OVERLAPPED structure that contains a handle to an event object. Otherwise, the function fails in unpredictable ways.

For overlapped operations, DeviceIoControl returns immediately, and the event object is signaled when the operation is complete. Otherwise, the function does not return until the operation is complete or an error occurs.

Return value

If the operation completes successfully, DeviceIoControl returns a nonzero value.

If the operation fails or is pending, DeviceIoControl returns zero. To get extended error information, call GetLastError.

Remarks

The optional output buffer returned through the lpOutBuffer parameter can be one of several structures depending on the value of the PropertyId member of theSTORAGE_PROPERTY_QUERY structure pointed to by the lpInBuffer parameter. These values are enumerated by the STORAGE_PROPERTY_ID enumeration. If the QueryTypemember of the STORAGE_PROPERTY_QUERY is set to PropertyExistsQuery then no structure is returned.

Value	lpOutBuffer structure
StorageDeviceProperty (0)	STORAGE_DEVICE_DESCRIPTOR
StorageAdapterProperty (1)	STORAGE_ADAPTER_DESCRIPTOR
StorageDeviceIdProperty (2)	STORAGE_DEVICE_ID_DESCRIPTOR
StorageDeviceUniqueIdProperty (3)	STORAGE_DEVICE_UNIQUE_IDENTIFIER
StorageDeviceWriteCacheProperty (4)	STORAGE_WRITE_CACHE_PROPERTY
StorageMiniportProperty (5)	STORAGE_MINIPORT_DESCRIPTOR
StorageAccessAlignmentProperty (6)	STORAGE_ACCESS_ALIGNMENT_DESCRIPTOR
StorageDeviceSeekPenaltyProperty (7)	DEVICE_SEEK_PENALTY_DESCRIPTOR
StorageDeviceTrimProperty (8)	DEVICE_TRIM_DESCRIPTOR
StorageDeviceWriteAggregationProperty(9)	DEVICE_WRITE_AGGREGATION_DESCRIPTOR
StorageDeviceLBProvisioningProperty (11)	DEVICE_LB_PROVISIONING_DESCRIPTOR
StorageDevicePowerProperty (12)	DEVICE_POWER_DESCRIPTOR
StorageDeviceCopyOffloadProperty (13)	DEVICE_COPY_OFFLOAD_DESCRIPTOR
StorageDeviceResiliencyProperty (14)	STORAGE_DEVICE_RESILIENCY_DESCRIPTOR