Source code of Windows XP (NT5)
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/*++
Copyright (C) 1999-2001 Microsoft Corporation
Module Name:
RESYNC.CPP
Abstract:
History:
a-davj 04-Mar-97 Created.
ivanbrug 01-Sep-2000 changed for svchost migration
--*/
#include "precomp.h"
#include <malloc.h>
#include <tchar.h>
#include "WinMgmt.h"
#include "resync.h"
// Timeout is a 64-bit value. See documentation on SetWaitableTimer
// for why we are setting it this way.
#define _SECOND 10000000
#define RESYNC_TIMEOUT_INTERVAL 10 * _SECOND
DWORD gdwADAPDelaySec = 0;
DWORD gdwLodCtrDelaySec = 0;
BOOL gfResyncInit = FALSE;
HANDLE ghWaitableTimer = NULL;
BOOL gfSpawnedResync = FALSE;
HANDLE ghResyncThreadHandle = NULL;
HANDLE ghResyncThreadEvent = NULL;
CRITICAL_SECTION* g_pResyncCs = NULL;
DWORD gdwResyncThreadId = 0;
// A global handle used to store the last dredger we
// kicked off!
HANDLE ghChildProcessHandle = NULL;
void ResetResyncTimer( HANDLE hResyncTimer, BOOL bIsLoadCtr )
{
DWORD dwErr = 0;
__int64 qwDueTime = bIsLoadCtr?(gdwLodCtrDelaySec * _SECOND):(gdwADAPDelaySec * _SECOND); // RESYNC_TIMEOUT_INTERVAL;
// Convert it to relative time
qwDueTime *= -1;
// Copy the relative time into a LARGE_INTEGER.
LARGE_INTEGER li;
li.LowPart = (DWORD) ( qwDueTime & 0xFFFFFFFF );
li.HighPart = (LONG) ( qwDueTime >> 32 );
if ( !SetWaitableTimer( hResyncTimer, &li, 0, NULL, NULL, FALSE ) )
{
dwErr = GetLastError();
}
}
// This thread controls the actual shelling of a resync perf operation
DWORD WINAPI ResyncPerfThread( void* pVoid )
{
RESYNCPERFDATASTRUCT* pResyncPerfData = (RESYNCPERFDATASTRUCT*) pVoid;
// We get the two handles, copy them and wait on them
// The first handle is the terminate event, the second is the
// timer on which to spin off the resync
BOOL bIsLodCtr = pResyncPerfData->m_bIsLodCtr;
HANDLE aHandles[2];
aHandles[0] = pResyncPerfData->m_hTerminate;
HANDLE hTimer = pResyncPerfData->m_hWaitableTimer;
CRITICAL_SECTION* pcs = pResyncPerfData->m_pcs;
BOOL bFullDredge = pResyncPerfData->m_fFullDredge;
delete pResyncPerfData;
pResyncPerfData = NULL;
// Reset the spawned flag
gfSpawnedResync = FALSE;
// Okay. Signal this event so the starting thread can get us going
SetEvent( ghResyncThreadEvent );
// Now, if ghChildProcessHandle is not NULL, then we've obviously kicked off a
// dredge before. See where the last one is at. If it's not done, wait for
// it to finish. We will always check this at the start of this chunk of code,
// since we are really the only location in which the process handle can ever get set,
// and there really shouldn't be more than one thread ever, waiting to start another
// dredge
if ( NULL != ghChildProcessHandle )
{
aHandles[1] = ghChildProcessHandle;
DWORD dwWait = WaitForMultipleObjects( 2, aHandles, FALSE, INFINITE );
// If abort was signalled, leave!
if ( dwWait == WAIT_OBJECT_0 )
{
return 0;
}
// If the process handle was signalled, close the process, reset the timer
// and we'll get ready to start the next dredge!
if ( dwWait == WAIT_OBJECT_0 + 1 )
{
EnterCriticalSection( pcs );
CloseHandle( ghChildProcessHandle );
ghChildProcessHandle = NULL;
ResetResyncTimer( hTimer, bIsLodCtr );
LeaveCriticalSection( pcs );
}
}
else
{
// If the Child Process Handle is NULL, we've never dredged before, so we'll
// just reset the timer
ResetResyncTimer( hTimer, bIsLodCtr );
}
BOOL fHoldOff = TRUE;
// Reset this handle to the timer now
aHandles[1] = hTimer;
while ( fHoldOff )
{
// Wait for either the terminate event or the timer
DWORD dwWait = WaitForMultipleObjects( 2, aHandles, FALSE, INFINITE );
// This means the terminate was signaled
if ( dwWait == WAIT_OBJECT_0 )
{
break;
} else
// This means the timer was signaled
if ( dwWait == WAIT_OBJECT_0 + 1 )
{
EnterCriticalSection( pcs );
// Finally, if the current thread id != gdwResyncThreadId, this means another
// resync perf thread got kicked off, inside of the critical section,
// so we should just let it wait on the timer. We don't really need to do
// this, since the main thread will wait on this thread to complete before
// it actually kicks off another thread.
if ( GetCurrentThreadId() != gdwResyncThreadId )
{
// Used the following int 3 for debugging
// _asm int 3;
LeaveCriticalSection( pcs );
break;
}
// Once we get through the critical section, check that the
// timer is still signalled. If it is not, this means that somebody
// got control of the critical section and reset the timer
if ( WaitForSingleObject( aHandles[1], 0 ) == WAIT_OBJECT_0 )
{
// Last quick sanity check on the abort event
if ( WaitForSingleObject( aHandles[0], 0 ) == WAIT_OBJECT_0 )
{
// Outa here!
LeaveCriticalSection( pcs );
break;
}
// Okay, we really will try to create the process now.
gfSpawnedResync = TRUE;
// We signalled to start the process, so make it so.
PROCESS_INFORMATION pi;
STARTUPINFO si;
memset(&si, 0, sizeof(si));
si.cb = sizeof(si);
TCHAR * pWritebleBuffer = (TCHAR *)_alloca(sizeof(__T("WMIADAP.EXE /F"))+2);
lstrcpy(pWritebleBuffer,(bFullDredge?__T("WMIADAP.EXE /F"):__T("WMIADAP.EXE")));
BOOL bRes = CreateProcess(NULL,
pWritebleBuffer,
NULL,
NULL,
FALSE,
CREATE_NO_WINDOW,
NULL,
NULL,
&si,
&pi);
if(bRes)
{
// Who cares about this one?
CloseHandle(pi.hThread);
// Clean up our old values
if ( NULL != ghChildProcessHandle )
{
CloseHandle( ghChildProcessHandle );
ghChildProcessHandle = NULL;
}
ghChildProcessHandle = pi.hProcess;
}
// We're done
fHoldOff = FALSE;
} // Check that we're still signalled, or we will just have to go back to waiting
LeaveCriticalSection( pcs );
} // IF timer was signalled
} // WHILE fHoldOff
return 0;
}
// For the waitable timer
//#define _SECOND 10000000
// Create all the things we need
BOOL InitResync( void )
{
if ( gfResyncInit )
return gfResyncInit;
if ( NULL == ghWaitableTimer )
{
ghWaitableTimer = CreateWaitableTimerW( NULL, TRUE, NULL );
// We gotta big problem
if ( NULL == ghWaitableTimer )
{
// Log an error here
ERRORTRACE( ( LOG_WINMGMT, "Could not create a waitable timer for Resyncperf.\n" ) );
}
}
if ( NULL == ghResyncThreadEvent )
{
ghResyncThreadEvent = CreateEvent( NULL, FALSE, FALSE, NULL );
// We gotta big problem
if ( NULL == ghResyncThreadEvent )
{
// Log an event here
ERRORTRACE( ( LOG_WINMGMT, "Could not create a ResyncThreadEvent event for Resyncperf.\n" ) );
}
}
// This critical section won't be freed or deleted because of
// potential timing issues. But since it's only one, I think
// we can live with it.
if ( NULL == g_pResyncCs )
{
g_pResyncCs = new CRITICAL_SECTION;
// We gotta big problem
if ( NULL == g_pResyncCs )
{
// Log an event here
ERRORTRACE( ( LOG_WINMGMT, "Could not create a ResyncCs critical section for Resyncperf.\n" ) );
}
else
{
InitializeCriticalSection( g_pResyncCs );
}
}
gfResyncInit = ( NULL != ghWaitableTimer &&
NULL != g_pResyncCs &&
NULL != ghResyncThreadEvent );
// Read the initialization information
Registry reg;
if ( Registry::no_error == reg.Open( HKEY_LOCAL_MACHINE, L"Software\\Microsoft\\WBEM\\CIMOM" ) )
{
long lError = reg.GetDWORD( L"ADAPDelay", &gdwADAPDelaySec );
if ( Registry::no_error == lError )
{
//This is what we want
}
else if ( ERROR_FILE_NOT_FOUND == reg.GetLastError() )
{
// Not set, so add it
reg.SetDWORD( L"ADAPDelay", WMIADAP_DEFAULT_DELAY );
gdwADAPDelaySec = WMIADAP_DEFAULT_DELAY;
}
else
{
// Error
ERRORTRACE( ( LOG_WINMGMT, "ResyncPerf experienced an error while attempting to read the WMIADAPDelay value in the CIMOM subkey. Continuing using a default value.\n" ) );
gdwADAPDelaySec = WMIADAP_DEFAULT_DELAY;
}
lError = reg.GetDWORD( L"LodCtrDelay", &gdwLodCtrDelaySec );
if ( Registry::no_error == lError )
{
//This is what we want
}
else if ( ERROR_FILE_NOT_FOUND == reg.GetLastError() )
{
// Not set, so add it
reg.SetDWORD( L"LodCtrDelay", WMIADAP_DEFAULT_DELAY );
gdwLodCtrDelaySec = WMIADAP_DEFAULT_DELAY_LODCTR;
}
else
{
// Error
ERRORTRACE( ( LOG_WINMGMT, "ResyncPerf experienced an error while attempting to read the WMIADAPDelay value in the CIMOM subkey. Continuing using a default value.\n" ) );
gdwLodCtrDelaySec = WMIADAP_DEFAULT_DELAY_LODCTR;
}
}
else
{
// Error
ERRORTRACE( ( LOG_WINMGMT, "ResyncPerf could not open the CIMOM subkey to read initialization data. Continuing using a default value.\n" ) );
gdwADAPDelaySec = WMIADAP_DEFAULT_DELAY;
gdwLodCtrDelaySec = WMIADAP_DEFAULT_DELAY_LODCTR;
}
return gfResyncInit;
}
// PLEASE NOTE - THIS FUNCTION IS NOT REENTRANT! PLEASE DO NOT CALL IT ON MULTIPLE THREADS!
void ResyncPerf( HANDLE hTerminate, BOOL bIsLodCtr )
{
// Assume that we should check the timer
BOOL fFirstTime = !gfResyncInit;
if ( !InitResync() )
return;
EnterCriticalSection( g_pResyncCs );
// Now, if this or the first time, or the spawned resyncflag is set to TRUE, then we need
// to kick off another thread. By checking gfSpawnedResync in a critical section, since
// it only gets set in the same critical section, we ensure that we will resignal as needed
// as well as only kick off a thread when we really need to.
BOOL fSpawnThread = ( fFirstTime || gfSpawnedResync );
if ( !fSpawnThread )
{
// We are here because we don't appear to have spawned a resync.
// This is either because we are servicing many lodctr requests
// within our time delay, or a dredger was started and
// a previous request request to dredge is waiting for
// the process to complete. If the child process handle
// is not NULL, there is no real need to reset the
// waitable timer
if ( NULL == ghChildProcessHandle && ghResyncThreadHandle )
{
// Reset the timer here
ResetResyncTimer( ghWaitableTimer , bIsLodCtr );
}
}
LeaveCriticalSection( g_pResyncCs );
if ( fSpawnThread )
{
HANDLE ahHandle[2];
if ( NULL != ghResyncThreadHandle )
{
ahHandle[0] = hTerminate;
ahHandle[1] = ghResyncThreadHandle;
// Wait for ten seconds on this handle. If it is not signalled, something is
// direly wrong. We're probably not going to be able to kick off a dredge
// so put some info to this effect in the error log. The only time we should
// have contention here, is when a lodctr event is signalled, just as the timer
// becomes signalled. The resync thread will wake up and start another dredge
// this thread will wait for the other thread to complete before continuing.
// We will kick off another resync thread, which will start another dredge,
// but it will wait for the first dredge to continue. This is a worst case
// scenario, and arguably kicking off two dredges isn't that bad of a bailout
DWORD dwRet = WaitForMultipleObjects( 2, ahHandle, FALSE, 10000 );
// We're done
if ( dwRet == WAIT_OBJECT_0 )
{
return;
}
if ( dwRet != WAIT_OBJECT_0 + 1 )
{
ERRORTRACE( ( LOG_WINMGMT, "The wait for a termination event or ResyncThreadHandle timed out in Resyncperf.\n" ) );
return;
}
CloseHandle( ghResyncThreadHandle );
ghResyncThreadHandle = NULL;
}
EnterCriticalSection( g_pResyncCs );
DWORD dwThreadId = 0;
RESYNCPERFDATASTRUCT* pResyncData = new RESYNCPERFDATASTRUCT;
// Boy are we low on memory!
if ( NULL == pResyncData )
{
LeaveCriticalSection( g_pResyncCs );
// Log an event here
ERRORTRACE( ( LOG_WINMGMT, "Could not create a RESYNCPERFDATASTRUCT in Resyncperf.\n" ) );
return;
}
// Store the data for the resync operation
pResyncData->m_hTerminate = hTerminate;
pResyncData->m_hWaitableTimer = ghWaitableTimer;
pResyncData->m_pcs = g_pResyncCs;
pResyncData->m_fFullDredge = fFirstTime;
pResyncData->m_bIsLodCtr = bIsLodCtr;
ghResyncThreadHandle = CreateThread( NULL, 0,
(LPTHREAD_START_ROUTINE)ResyncPerfThread, (void*) pResyncData,
0, &gdwResyncThreadId );
LeaveCriticalSection( g_pResyncCs );
if ( NULL == ghResyncThreadHandle )
{
LeaveCriticalSection( g_pResyncCs );
// Log an event here
ERRORTRACE( ( LOG_WINMGMT, "Could not create a ResyncPerfThread thread in Resyncperf.\n" ) );
return;
}
else
{
// Wait for the resync thread event to be signalled by the thread we just started.
// If it doesn't signal in 10 seconds, something is VERY wrong
DWORD dwWait = WaitForSingleObject( ghResyncThreadEvent, INFINITE );
if ( dwWait != WAIT_OBJECT_0 )
{
// Log an event
ERRORTRACE( ( LOG_WINMGMT, "The ResyncPerfThread thread never signaled the ghResyncThreadEvent in Resyncperf.\n" ) );
return;
}
}
} // IF fSpawnThread
}