【转帖】驱动程序和应用程序之间通信（For Win2000 or later version)

╰+攻爆jí腚メ 2022-08-24 00:41 167阅读 0赞

正文  
Q:  
请问有什么方法实现驱动程序主动和应用程序进行实时通讯，而不用应用程序采用定时查询的方法？  
比如驱动有一事件发生需要立即通知应用程序，或驱动程序需要向应用程序读取一些内容.  
  
A:  
有一个很容易的方式，在驱动程序和应用程序之间用一个事件。  
在应用程序CreateFile的时候，驱动程序IoCreateSynchronizationEvent一个有名的事件，然后应用程序CreateEvent/OpenEvent此有名事件即可。  
注意点：  
1，不要在驱动初始化的时候创建事件，此时大多不能成功创建；  
2，让驱动先创建，那么此后应用程序打开时，只能读（Waitxxxx）,不能写(SetEvent/ResetEvent)。反之，如果应用程序先创建，则应用程序和驱动程序都有读写权限；  
3，用名字比较理想，注意驱动中名字在/BaseNamedObjects/下，例如应用程序用“xxxEvent”,那么驱动中就是“/BaseNamedObjects/xxxEvent”；  
4，用HANDLE的方式也可以，但是在WIN98下是否可行，未知。  
5，此后，驱动对读请求应立即返回，否则就返回失败。不然将失去用事件通知的意义（不再等待读完成，而是有需要（通知事件）时才会读）；  
6，应用程序发现有事件，应该在一个循环中读取，直到读取失败，表明没有数据可读；否则会漏掉后续数据，而没有及时读取；  
  
Sample Code:  
  
  
// Describe the share memory.  
typedef struct \_PKT\_BUFFER  
\{  
PMDL BufferMdl;  
PVOID UserBaseAddress;  
PVOID KernelBaseAddress;  
\}PKT\_BUFFER, \*PPKT\_BUFFER;  
  
typedef struct \_SHARE\_EVENT\_CONTEXT  
\{  
WCHAR EventName\[128\]; // Event name, the only connection btw ring0/ring3  
HANDLE Win32EventHandle; // Ring3 copy of the event handle  
HANDLE DriverEventHandle; // Ring0 copy of the event handle  
PVOID DriverEventObject; // The event object  
\}SHARE\_EVENT\_CONTEXT, \*PSHARE\_EVENT\_CONTEXT;  
  
  
BOOLEAN CreateShareMemory(PPKT\_BUFFER PktBuffer, ULONG Size)  
\{  
PktBuffer->KernelBaseAddress = ExAllocatePoolWithTag(NonPagedPool,  
Size,  
'MpaM');  
  
if(!PktBuffer->KernelBaseAddress)  
return FALSE;  
  
//  
// Allocate and initalize an MDL that describes the buffer  
//  
PktBuffer->BufferMdl = IoAllocateMdl(PktBuffer->KernelBaseAddress,  
Size,  
FALSE,  
FALSE,  
NULL);  
  
if(!PktBuffer->BufferMdl)  
\{  
ExFreePool(PktBuffer->KernelBaseAddress);  
PktBuffer->KernelBaseAddress =NULL;  
return FALSE;  
\}  
  
MmBuildMdlForNonPagedPool(PktBuffer->BufferMdl);  
  
DEBUGP(DL\_INFO, ("CreateShareMemory: KernelBaseAddress = 0x%p/n", PktBuffer->KernelBaseAddress));  
  
return TRUE;  
\}  
  
VOID DestroyShareMemory(PPKT\_BUFFER PktBuffer)  
\{  
if(PktBuffer->BufferMdl)  
\{  
IoFreeMdl(PktBuffer->BufferMdl);  
PktBuffer->BufferMdl = NULL;  
\}  
  
if(PktBuffer->KernelBaseAddress)  
\{  
ExFreePool(PktBuffer->KernelBaseAddress);  
PktBuffer->KernelBaseAddress = NULL;  
\}  
\}  
  
//This function works in user dispatch code.  
BOOLEAN MapSharedMemory(PPKT\_BUFFER PktBuffer)  
\{  
if(!PktBuffer->BufferMdl)  
return FALSE;  
  
//  
// The preferred V5 way to map the buffer into user space  
//  
PktBuffer->UserBaseAddress =  
MmMapLockedPagesSpecifyCache(PktBuffer->BufferMdl, // MDL  
UserMode, // Mode  
MmCached, // Caching  
NULL, // Address  
FALSE, // Bugcheck?  
NormalPagePriority); // Priority  
  
if(!PktBuffer->UserBaseAddress)  
return FALSE;  
  
DEBUGP(DL\_INFO, ("MapSharedMemory SUCCESS, UserBaseAddress %p/n", PktBuffer->UserBaseAddress));  
return TRUE;  
\}  
  
VOID UnmapSharedMemory(PPKT\_BUFFER PktBuffer)  
\{  
if(PktBuffer->UserBaseAddress)  
\{  
MmUnmapLockedPages(PktBuffer->UserBaseAddress, PktBuffer->BufferMdl);  
PktBuffer->UserBaseAddress = NULL;  
\}  
\}  
  
BOOLEAN CreateShareEvent(PSHARE\_EVENT\_CONTEXT ShareEvent)  
\{  
UNICODE\_STRING UnicodeName;  
WCHAR UnicodeBuffer\[128\] = L"/BaseNamedObjects/";  
  
RtlInitUnicodeString(&UnicodeName, UnicodeBuffer);  
UnicodeName.MaximumLength = 128;  
RtlAppendUnicodeToString(&UnicodeName, ShareEvent->EventName);  
  
ShareEvent->DriverEventObject = IoCreateSynchronizationEvent(&UnicodeName,  
&ShareEvent->DriverEventHandle);  
  
if(ShareEvent->DriverEventObject == NULL)  
\{  
ShareEvent->DriverEventHandle = NULL;  
DEBUGP(DL\_INFO, ("CreateSynchronizationEvent FAILED Name=%ws/n", UnicodeBuffer));  
return FALSE;  
\}  
else  
\{  
KeClearEvent(ShareEvent->DriverEventObject);  
  
DEBUGP(DL\_INFO, ("CreateSynchronizationEvent SUCCESS Name=%ws DriverEventObject=%p, DriverEventHandle=%u/n",  
UnicodeBuffer,  
ShareEvent->DriverEventObject,  
ShareEvent->DriverEventHandle));  
  
return TRUE;  
\}  
\}  
  
VOID DestroyShareEvents(PSHARE\_EVENT\_CONTEXT ShareEvent)  
\{  
if(ShareEvent->DriverEventHandle)  
\{  
ZwClose(ShareEvent->DriverEventHandle);  
ShareEvent->DriverEventObject = NULL;  
ShareEvent->DriverEventHandle = NULL;  
\}  
\}