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[1]; } 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[1]; } 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 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 ); } query.PropertyId = StorageDeviceProperty; query.QueryType = PropertyStandardQuery; pDevDescHeader = (STORAGE_DESCRIPTOR_HEADER *) malloc( sizeof(STORAGE_DESCRIPTOR_HEADER) ); if ( NULL == pDevDescHeader ) { return (DWORD) -1; } 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( -1 ); } devDescLength = pDevDescHeader->Size; pDevDesc = (STORAGE_DEVICE_DESCRIPTOR *) malloc( devDescLength ); if ( NULL == pDevDesc ) { free( pDevDescHeader ); return (DWORD) -1; } 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( -1 ); } //printf("%d\n", pDevDesc->BusType); *type = (WORD) pDevDesc->BusType; free( pDevDescHeader ); free( pDevDesc ); (void) CloseHandle( hDevice ); return 0; }

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.

ValuelpOutBuffer structureStorageDeviceProperty (0)STORAGE_DEVICE_DESCRIPTORStorageAdapterProperty (1)STORAGE_ADAPTER_DESCRIPTORStorageDeviceIdProperty (2)STORAGE_DEVICE_ID_DESCRIPTORStorageDeviceUniqueIdProperty (3)STORAGE_DEVICE_UNIQUE_IDENTIFIERStorageDeviceWriteCacheProperty (4)STORAGE_WRITE_CACHE_PROPERTYStorageMiniportProperty (5)STORAGE_MINIPORT_DESCRIPTORStorageAccessAlignmentProperty (6)STORAGE_ACCESS_ALIGNMENT_DESCRIPTORStorageDeviceSeekPenaltyProperty (7)DEVICE_SEEK_PENALTY_DESCRIPTORStorageDeviceTrimProperty (8)DEVICE_TRIM_DESCRIPTORStorageDeviceWriteAggregationProperty(9)DEVICE_WRITE_AGGREGATION_DESCRIPTORStorageDeviceLBProvisioningProperty (11)DEVICE_LB_PROVISIONING_DESCRIPTORStorageDevicePowerProperty (12)DEVICE_POWER_DESCRIPTORStorageDeviceCopyOffloadProperty (13)DEVICE_COPY_OFFLOAD_DESCRIPTORStorageDeviceResiliencyProperty (14)STORAGE_DEVICE_RESILIENCY_DESCRIPTOR

转载于:https://www.cnblogs.com/shangdawei/p/3164005.html

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