131 lines
2.7 KiB
C++
131 lines
2.7 KiB
C++
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/******************************************************************************
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*
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* Copyright (c) 2000 Microsoft Corporation
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*
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* Module Name:
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* rwlock.cpp
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*
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* Abstract:
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* Implements CLock - for synchronizing access to a resource
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*
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* Revision History:
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* Brijesh Krishnaswami (brijeshk) 04/13/2000
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* created
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*
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*****************************************************************************/
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#include <nt.h>
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#include <ntrtl.h>
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#include <nturtl.h>
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#include <windows.h>
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#include "utils.h"
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#include <accctrl.h>
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#include "dbgtrace.h"
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#include "srdefs.h"
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#ifdef THIS_FILE
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#undef THIS_FILE
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#endif
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static char __szTraceSourceFile[] = __FILE__;
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#define THIS_FILE __szTraceSourceFile
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//////////////////////////////////////////////////////////////////////
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// CLock - class that allows exclusive access to a resource
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// uses a mutex - does not differentiate between readers/writers
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CLock::CLock() // object constructor
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{
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hResource = NULL;
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}
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DWORD CLock::Init()
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{
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DWORD dwRc = ERROR_SUCCESS;
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//
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// first - try opening the mutex
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//
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hResource = OpenMutex(SYNCHRONIZE, FALSE, s_cszDSMutex);
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if (hResource)
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{
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goto done;
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}
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//
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// if doesn't exist - create it
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//
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hResource = CreateMutex(NULL, FALSE, s_cszDSMutex);
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dwRc = GetLastError();
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if (! hResource)
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goto done;
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if (dwRc == ERROR_SUCCESS)
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{
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dwRc = SetAclInObject(hResource,
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SE_KERNEL_OBJECT,
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STANDARD_RIGHTS_ALL | GENERIC_ALL,
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SYNCHRONIZE,
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FALSE);
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}
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else // we got a good handle, so we don't care
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{
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dwRc = ERROR_SUCCESS;
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}
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done:
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return dwRc;
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}
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CLock::~CLock() // object destructor
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{
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if (hResource)
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CloseHandle(hResource);
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}
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BOOL CLock::Lock(int iTimeOut) // Get access to the resource w/ Timeout
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{
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DWORD dwRc;
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BOOL fRet;
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DWORD dwId = GetCurrentThreadId();
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tenter("CLock::Lock");
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ASSERT(hResource != NULL);
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dwRc = WaitForSingleObject(hResource, iTimeOut);
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if (dwRc == WAIT_OBJECT_0 || dwRc == WAIT_ABANDONED)
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{
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trace(0, "Thread(%08x) got DS lock", dwId);
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fRet = TRUE;
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}
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else
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{
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trace(0, "Thread(%08x) cannot get DS lock", dwId);
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fRet = FALSE;
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}
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tleave();
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return fRet;
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}
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void CLock::Unlock() // Relinquish access to the resource
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{
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tenter("CLock::Unlock");
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DWORD dwId = GetCurrentThreadId();
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ASSERT(hResource != NULL);
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ReleaseMutex(hResource);
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trace(0, "Thread(%08x) released DS lock", dwId);
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tleave();
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}
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