exclusion.h
#define UNIQUE_TO_SYSTEM 0 #define UNIQUE_TO_DESKTOP 1 #define UNIQUE_TO_SESSION 2 #define UNIQUE_TO_TRUSTEE 3 CString createExclusionName(LPCTSTR GUID, UINT kind = UNIQUE_TO_SYSTEM);
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exclusion.cpp
#include "stdafx.h" #include "exclusion.h"
/****************************************************************************
* createExclusionName
* Inputs:
* LPCTSTR GUID: The GUID for the exclusion
* UINT kind: Kind of exclusion
* UNIQUE_TO_SYSTEM
* UNIQUE_TO_DESKTOP
* UNIQUE_TO_SESSION
* UNIQUE_TO_TRUSTEE
* Result: CString
* A name to use for the exclusion mutex
* Effect:
* Creates the exclusion mutex name
* Notes:
* The GUID is created by a declaration such as
* #define UNIQUE _T("MyAppName-{44E678F7-DA79-11d3-9FE9-006067718D04}")
****************************************************************************/
CString createExclusionName(LPCTSTR GUID, UINT kind)
{
switch(kind)
{ /* kind */
case UNIQUE_TO_SYSTEM:
return CString(GUID);
case UNIQUE_TO_DESKTOP:
{ /* desktop */
CString s = GUID;
DWORD len;
HDESK desktop = GetThreadDesktop(GetCurrentThreadId());
BOOL result = GetUserObjectInformation(desktop, UOI_NAME, NULL, 0, &len);
DWORD err = ::GetLastError();
if(!result && err == ERROR_INSUFFICIENT_BUFFER)
{ /* NT/2000 */
LPBYTE data = new BYTE[len];
result = GetUserObjectInformation(desktop, UOI_NAME, data, len, &len);
s += _T("-");
s += (LPCTSTR)data;
delete [ ] data;
} /* NT/2000 */
else
{ /* Win9x */
s += _T("-Win9x");
} /* Win9x */
return s;
} /* desktop */
case UNIQUE_TO_SESSION:
{ /* session */
CString s = GUID;
HANDLE token;
DWORD len;
BOOL result = OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &token);
if(result)
{ /* NT */
GetTokenInformation(token, TokenStatistics, NULL, 0, &len);
LPBYTE data = new BYTE[len];
GetTokenInformation(token, TokenStatistics, data, len, &len);
LUID uid = ((PTOKEN_STATISTICS)data)->AuthenticationId;
delete [ ] data;
CString t;
t.Format(_T("-%08x%08x"), uid.HighPart, uid.LowPart);
return s + t;
} /* NT */
else
{ /* 16-bit OS */
return s;
} /* 16-bit OS */
} /* session */
case UNIQUE_TO_TRUSTEE:
{ /* trustee */
CString s = GUID;
#define NAMELENGTH 64
TCHAR userName[NAMELENGTH];
DWORD userNameLength = NAMELENGTH;
TCHAR domainName[NAMELENGTH];
DWORD domainNameLength = NAMELENGTH;
if(GetUserName(userName, &userNameLength))
{ /* get network name */
// The NetApi calls are very time consuming
// This technique gets the domain name via an
// environment variable
domainNameLength = ExpandEnvironmentStrings(_T("%USERDOMAIN%"),
domainName,
NAMELENGTH);
CString t;
t.Format(_T("-%s-%s"), domainName, userName);
s += t;
} /* get network name */
return s;
} /* trustee */
default:
ASSERT(FALSE);
break;
} /* kind */
return CString(GUID);
} // createExclusionName
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Back in the original example, replace the string which I hardwired into the ::CreateMutex call with a call on createExclusionName with the desired specification to get a correctly-formatted unique name to use for the Mutex.
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