首先看到下面一个例子：
$strComputer = "."
$objWMIService = ObjGet("winmgmts://" & $strComputer & "/root/cimv2")
$strWQL = "SELECT * " & _
"FROM __InstanceCreationEvent " & _
"WITHin$2 " & _
"WHERE TargetInstance ISA 'Win32_Process' " & _
"AND TargetInstance.Name = 'notepad.exe'"
ConsoleWrite( "Waiting for a new instance of Notepad to start..." & @CrLf )
$objEventSource = $objWMIService.ExecNotificationQuery($strWQL)
$objEventObject = $objEventSource.NextEvent()
ConsoleWrite( "A new instance of Notepad was just started." & @CrLf )
当你运行记事本时程序就会发出一条提示。下面是对这段代码的解释：
$strComputer = "."
$objWMIService = ObjGet("winmgmts://" & $strComputer & "/root/cimv2")
连接到命名空间。
$strWQL = "SELECT * " & _
"FROM __InstanceCreationEvent " & _
"WITHin 2 " & _
"WHERE TargetInstance ISA 'Win32_Process' " & _
"AND TargetInstance.Name = 'notepad.exe'"
这是一段WQL查询代码，__InstanceCreationEvent 表示监视新实例的建立，在这里表示新进程建立。类似的东西还有__InstanceModificationEvent、__InstanceDeletionEvent、__InstanceOperationEvent，它们分别表示修改、删除、全部操作（既以上三种的综合）。WITHin 2 表示每两秒查询一次。TargetInstance ISA 'Win32_Process' 表示监控Win32_Process类。TargetInstance.Name = 'notepad.exe'表示监控Name属性为notepad.exe的实例。
$objEventSource = $objWMIService.ExecNotificationQuery($strWQL)
$objEventObject = $objEventSource.NextEvent()
ExecNotificationQuery和ExecQuery的意义差不多一样，不过前者是专门用来获取WMI事件。$objEventSource.NextEvent() 表示不断进行WQL查询，直到通知产生，这段时间内脚本会暂停。
另外，用$objEventObject.Path_.Class你可以获取通知的种类，比如__InstanceCreationEvent。你还可以用$objEventObject.TargetInstance.+属性 来获取产生通知的实例的属性。
理论就讲到这里，剩下的东西相信大家看了下面的几个例子后就明白了。
下面是一段监视进程的范例：
$strComputer = "."
$objWMIService = ObjGet("winmgmts://" & $strComputer & "/root/cimv2")
$strQuery = "SELECT * " & _
"FROM __InstanceOperationEvent " & _
"WITHin 2 " & _
"WHERE TargetInstance ISA 'Win32_Process' "
$objEventSource = $objWMIService.ExecNotificationQuery($strQuery)
ConsoleWrite( "进程监控开始..." & @CRLF )
While 1
$objEventObject = $objEventSource.NextEvent()
Switch $objEventObject.Path_.Class
Case "__InstanceCreationEvent"
ConsoleWrite("新进程建立:" & $objEventObject.TargetInstance.Name & @CrLf )
Case "__InstanceDeletionEvent"
ConsoleWrite("进程被关闭:" & $objEventObject.TargetInstance.Name & @CrLf )
EndSwitch
WEnd
下面是一段文件监控的例子：
$strComputer = "."
$objWMIService = ObjGet("winmgmts:\\" & $strComputer & "\root\cimv2")
$colMonitoredEvents = $objWMIService.ExecNotificationQuery _
("SELECT * FROM __InstanceOperationEvent WITHIN 5 WHERE " _
& "Targetinstance ISA 'CIM_DirectoryContainsFile' and " _
& "TargetInstance.GroupComponent= " _
& "'Win32_Directory.Name=""c:\\\\1""'")
While 1
$objEventObject = $colMonitoredEvents.NextEvent()
Select
Case $objEventObject.Path_.Class()="__InstanceCreationEvent"
ConsoleWrite ("A new file was just created: " & $objEventObject.TargetInstance.PartComponent() & @CR)
Case $objEventObject.Path_.Class()="__InstanceDeletionEvent"
ConsoleWrite ("A file was just deleted: " & $objEventObject.TargetInstance.PartComponent() & @CR)
EndSelect
WEnd
下面是监控USB设备的例子：
$strComputer = "."
$objWMIService = ObjGet("winmgmts:\\" & $strComputer & "\root\cimv2")
$colEvents = $objWMIService.ExecNotificationQuery _
("Select * From __InstanceOperationEvent Within 5 Where " _
& "TargetInstance isa 'Win32_LogicalDisk'")
While 1
$objEvent = $colEvents.NextEvent
If $objEvent.TargetInstance.DriveType = 2 Then
Select
Case $objEvent.Path_.Class()="__InstanceCreationEvent"
Consolewrite("Drive " & $objEvent.TargetInstance.DeviceId & "has been added." & @CR)
Case $objEvent.Path_.Class()="__InstanceDeletionEvent"
Consolewrite("Drive " & $objEvent.TargetInstance.DeviceId & "has been removed."& @CR)
EndSelect
EndIf
WEnd
#define _WIN32_DCOM
#endif
#include <windows.h>
#include <objbase.h>
#include <atlbase.h>
#include <iostream>
#include <wbemidl.h>
#include <comutil.h>
#include <string.h>
int main( int argc, char** argv )
{
HRESULT hr = CoInitializeEx( NULL, COINIT_MULTITHREADED );
if ( FAILED( hr ) )
{
std::cerr << "COM initialization failed" << std::endl;
return -1;
}
// setup process-wide security context
hr = CoInitializeSecurity( NULL, // we're not a server
-1, // we're not a server
NULL, // dito
NULL, // reserved
RPC_C_AUTHN_LEVEL_DEFAULT, // let DCOM decide
RPC_C_IMP_LEVEL_IMPERSONATE,
NULL,
EOAC_NONE,
NULL );
if ( FAILED( hr ) )
{
std::cerr << "Security initialization failed" << std::endl;
return -1;
}
int result = 0;
// we're going to use CComPtr<>s, whose lifetime must end BEFORE CoUnitialize is called
{
// connect to WMI
CComPtr< IWbemLocator > locator;
hr = CoCreateInstance( CLSID_WbemAdministrativeLocator, NULL,
CLSCTX_INPROC_SERVER,
IID_IWbemLocator, reinterpret_cast< void** >( &locator ) );
if ( FAILED( hr ) )
{
std::cerr << "Instantiation of IWbemLocator failed" << std::endl;
return -1;
}
// connect to local service with current credentials
CComPtr< IWbemServices > service;
hr = locator->ConnectServer( L"root\\cimv2", NULL, NULL, NULL,
WBEM_FLAG_CONNECT_USE_MAX_WAIT,
NULL, NULL, &service );
if ( SUCCEEDED( hr ) )
{
// execute a query
CComPtr< IEnumWbemClassObject > enumerator;
hr = service->ExecNotificationQuery( L"WQL", L"SELECT * FROM __InstanceOperationEvent WITHIN 5 WHERE ( TargetInstance ISA \'Win32_LogicalDisk\' ) ",
WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY, NULL, &enumerator );
std::cout << "QUERY " << hr << std::endl;
if ( SUCCEEDED( hr ) )
{
//#error "Comment out after read: program will terminate after two events; be sure not kill program by CTRL-C etc. See caveats section in article"
int count = 0;
do {
CComPtr< IWbemClassObject > folder = NULL;
ULONG retcnt = 0L;
while ( ( hr = enumerator->Next( WBEM_INFINITE, 1L, &folder, &retcnt ) ) == WBEM_S_TIMEDOUT );
if ( SUCCEEDED( hr ) && ( hr != WBEM_S_FALSE ) )
{
if ( retcnt > 0 )
{
_variant_t var_OP;
hr = folder->Get( L"__Class", 0, &var_OP, NULL, NULL );
_bstr_t vlOP = var_OP;
//count ++;
// query returns a result - handle the event
_variant_t var_val;
hr = folder->Get( L"TargetInstance", 0, &var_val, NULL, NULL );
if ( SUCCEEDED( hr ) )
{
IUnknown* str = var_val;
CComPtr< IWbemClassObject > obj;
hr = str->QueryInterface( IID_IWbemClassObject, reinterpret_cast< void** >( &obj ) );
if ( SUCCEEDED( hr ) )
{
_variant_t cn;
hr = obj->Get( L"__Class", 0, &cn, NULL, NULL );
if ( SUCCEEDED( hr ) )
{
_bstr_t name = cn;
if ( name == _bstr_t( L"Win32_LogicalDisk" ) )
{
_variant_t labl;
obj->Get( L"Name", 0, &labl, NULL, NULL );
_bstr_t vl = labl;
std::cout <<vlOP<< " Change to disk " << vl << std::endl;
}
}
}
}
else
{
std::cerr << "IWbemClassObject::Get failed" << std::endl;
result = -1;
}
break;
}
else
{
std::cout << "Enumeration empty" << std::endl;
}
}
else if ( FAILED( hr ) )
{
std::cerr << "Error in iterating through enumeration 0x" << std::hex << hr << std::dec << std::endl;
result = -1;
} else std::cout << "empty" << std::endl;
} while ( count < 2 );
}
else
{
std::cerr << "Query failed" << std::endl;
result = -1;
}
}
else
{
std::cerr << "Couldn't connect to service" << std::endl;
result = -1;
}
}
CoUninitialize();
return result;
}