windows驱动中NT风格路径和DOS风格路径转换

#include <ntddk.h>
#include <windef.h>
#include <ntstrsafe.h>

//输入\\??\\c:-->\\device\\\harddiskvolume1
//LinkTarget.Buffer注意要释放

NTSTATUS QuerySymbolicLink(
			IN PUNICODE_STRING SymbolicLinkName,
			OUT PUNICODE_STRING LinkTarget
			)                                  
{
	OBJECT_ATTRIBUTES	oa		= {0};
	NTSTATUS			status	= 0;
	HANDLE				handle	= NULL;

	InitializeObjectAttributes(
							&oa, 
							SymbolicLinkName,
							OBJ_CASE_INSENSITIVE,
							0, 
							0);

	status = ZwOpenSymbolicLinkObject(&handle, GENERIC_READ, &oa);
	if (!NT_SUCCESS(status))
	{
		return status;
	}

	LinkTarget->MaximumLength = MAX_PATH*sizeof(WCHAR);
	LinkTarget->Length = 0;
	LinkTarget->Buffer = ExAllocatePoolWithTag(PagedPool, LinkTarget->MaximumLength,'SOD');
	if (!LinkTarget->Buffer)
	{
		ZwClose(handle);
		return STATUS_INSUFFICIENT_RESOURCES;
	}

	RtlZeroMemory(LinkTarget->Buffer, LinkTarget->MaximumLength);

	status = ZwQuerySymbolicLinkObject(handle, LinkTarget, NULL);
	ZwClose(handle);

	if (!NT_SUCCESS(status))
	{
		ExFreePool(LinkTarget->Buffer);
	}

	return status;
}

//输入\\Device\\harddiskvolume1
//输出C:
//DosName.Buffer的内存记得释放

NTSTATUS
MyRtlVolumeDeviceToDosName(
						IN PUNICODE_STRING DeviceName,
						OUT PUNICODE_STRING DosName
						)

/*++

Routine Description:

This routine returns a valid DOS path for the given device object.
This caller of this routine must call ExFreePool on DosName->Buffer
when it is no longer needed.

Arguments:

VolumeDeviceObject - Supplies the volume device object.
DosName - Returns the DOS name for the volume
Return Value:

NTSTATUS

--*/

{
	NTSTATUS				status					= 0;
	UNICODE_STRING			driveLetterName			= {0};
	WCHAR					driveLetterNameBuf[128] = {0};
	WCHAR					c						= L'\0';
	WCHAR					DriLetter[3]			= {0};
	UNICODE_STRING			linkTarget				= {0};

	for (c = L'A'; c <= L'Z'; c++)
	{
		RtlInitEmptyUnicodeString(&driveLetterName,driveLetterNameBuf,sizeof(driveLetterNameBuf));
		RtlAppendUnicodeToString(&driveLetterName, L"\\??\\");
		DriLetter[0] = c;
		DriLetter[1] = L':';
		DriLetter[2] = 0;
		RtlAppendUnicodeToString(&driveLetterName,DriLetter);

		status = QuerySymbolicLink(&driveLetterName, &linkTarget);
		if (!NT_SUCCESS(status))
		{
			continue;
		}

		if (RtlEqualUnicodeString(&linkTarget, DeviceName, TRUE))
		{
			ExFreePool(linkTarget.Buffer);
			break;
		}

		ExFreePool(linkTarget.Buffer);
	}

	if (c <= L'Z')
	{
		DosName->Buffer = ExAllocatePoolWithTag(PagedPool, 3*sizeof(WCHAR), 'SOD');
		if (!DosName->Buffer)
		{
			return STATUS_INSUFFICIENT_RESOURCES;
		}

		DosName->MaximumLength = 6;
		DosName->Length   = 4;
		*DosName->Buffer  = c;
		*(DosName->Buffer+ 1) = ':';
		*(DosName->Buffer+ 2) = 0;

		return STATUS_SUCCESS;
	}

	return status;
} 

//c:\\windows\\hi.txt<--\\device\\harddiskvolume1\\windows\\hi.txt
BOOL NTAPI GetNTLinkName(IN WCHAR * wszNTName, OUT WCHAR * wszFileName)
{
	UNICODE_STRING		ustrFileName = {0};
	UNICODE_STRING		ustrDosName = {0};
	UNICODE_STRING		ustrDeviceName = {0};

	WCHAR				*pPath = NULL;
	ULONG				i = 0;
	ULONG				ulSepNum = 0;


	if (wszFileName == NULL ||
		wszNTName == NULL ||
		_wcsnicmp(wszNTName, L"\\device\\harddiskvolume", wcslen(L"\\device\\harddiskvolume"))!=0)
	{
		return FALSE;
	}

	ustrFileName.Buffer = wszFileName;
	ustrFileName.Length = 0;
	ustrFileName.MaximumLength = sizeof(WCHAR)*MAX_PATH;

	while(wszNTName[i]!=L'\0')
	{

		if (wszNTName[i] == L'\0')
		{
			break;
		}
		if (wszNTName[i] == L'\\')
		{
			ulSepNum++;
		}
		if (ulSepNum == 3)
		{
			wszNTName[i] = UNICODE_NULL;
			pPath = &wszNTName[i+1];
			break;
		}
		i++;
	}

	if (pPath == NULL)
	{
		return FALSE;
	}

	RtlInitUnicodeString(&ustrDeviceName, wszNTName);

	if (!NT_SUCCESS(MyRtlVolumeDeviceToDosName(&ustrDeviceName, &ustrDosName)))
	{
		return FALSE;
	}

	RtlCopyUnicodeString(&ustrFileName, &ustrDosName);
	RtlAppendUnicodeToString(&ustrFileName, L"\\");
	RtlAppendUnicodeToString(&ustrFileName, pPath);

	ExFreePool(ustrDosName.Buffer);

	return TRUE;
}

BOOL QueryVolumeName(WCHAR ch, WCHAR * name, USHORT size)
{
	WCHAR szVolume[7] = L"\\??\\C:";
	UNICODE_STRING LinkName;
	UNICODE_STRING VolName;
	UNICODE_STRING ustrTarget;
	NTSTATUS ntStatus = 0;
	
	RtlInitUnicodeString(&LinkName, szVolume);
	
	szVolume[4] = ch;

	ustrTarget.Buffer = name;
	ustrTarget.Length = 0;
	ustrTarget.MaximumLength = size;
	
	ntStatus = QuerySymbolicLink(&LinkName, &VolName);
	if (NT_SUCCESS(ntStatus))
	{
		RtlCopyUnicodeString(&ustrTarget, &VolName);
		ExFreePool(VolName.Buffer);
	}
	return NT_SUCCESS(ntStatus);
	
}

//\\??\\c:\\windows\\hi.txt-->\\device\\harddiskvolume1\\windows\\hi.txt

BOOL NTAPI GetNtDeviceName(IN WCHAR * filename, OUT WCHAR * ntname)
{
	UNICODE_STRING uVolName = {0,0,0};
	WCHAR volName[MAX_PATH] = L"";
	WCHAR tmpName[MAX_PATH] = L"";
	WCHAR chVol = L'\0';
	WCHAR * pPath = NULL;
	int i = 0;
	

	RtlStringCbCopyW(tmpName, MAX_PATH * sizeof(WCHAR), filename);
	
	for(i = 1; i < MAX_PATH - 1; i++)
	{
		if(tmpName[i] == L':')
		{
			pPath = &tmpName[(i + 1) % MAX_PATH];
			chVol = tmpName[i - 1];
			break;
		}
	}
	
	if(pPath == NULL)
	{
		return FALSE;
	}
	
	if(chVol == L'?')
	{
		uVolName.Length = 0;
		uVolName.MaximumLength = MAX_PATH * sizeof(WCHAR);
		uVolName.Buffer = ntname;
		RtlAppendUnicodeToString(&uVolName, L"\\Device\\HarddiskVolume?");
		RtlAppendUnicodeToString(&uVolName, pPath);
		return TRUE;
	}
	else if(QueryVolumeName(chVol, volName, MAX_PATH * sizeof(WCHAR)))
	{
		uVolName.Length = 0;
		uVolName.MaximumLength = MAX_PATH * sizeof(WCHAR);
		uVolName.Buffer = ntname;
		RtlAppendUnicodeToString(&uVolName, volName);
		RtlAppendUnicodeToString(&uVolName, pPath);
		return TRUE;
	}
	
	return FALSE;
}

VOID DriverUnload(PDRIVER_OBJECT pDriverObject)
{
	DbgPrint("Goodbye!\n");
}

NTSTATUS DriverEntry(PDRIVER_OBJECT pDriverObject, PUNICODE_STRING pRegPath)
{
	UNICODE_STRING		ustrDeviceName			= {0};
	UNICODE_STRING		ustrLinkName			= {0};
	WCHAR				*wszDeviceName			= L"\\Device\\harddiskvolume1";
	NTSTATUS			ntStatus				= 0;
	WCHAR			DeviceName[MAX_PATH]		= L"\\Device\\harddiskvolume1\\windows\\hi.txt";
	WCHAR			FileName[MAX_PATH]		= {0};
	WCHAR			szDeviceName[MAX_PATH]  = {0};

	RtlInitUnicodeString(&ustrDeviceName, wszDeviceName);

	ntStatus = MyRtlVolumeDeviceToDosName(&ustrDeviceName, &ustrLinkName);
	if (NT_SUCCESS(ntStatus))
	{
		
		DbgPrint("linkname:%wZ\n", &ustrLinkName);
		if (ustrLinkName.Buffer)
		{
			ExFreePool(ustrLinkName.Buffer);
		}
	}
	if (GetNTLinkName(DeviceName, FileName))
	{
		DbgPrint("FileName:%ws\n", FileName);
		GetNtDeviceName(FileName, szDeviceName);
		DbgPrint("szDeviceName:%ws", szDeviceName);
	}

	pDriverObject->DriverUnload = DriverUnload;
	
	return STATUS_SUCCESS;

}