Get logged-on username/SID via a service app

[Griffyn]

Hi all,

I have a service application that needs to find the currently logged on user (to identify their registry hive in HKEY_USERS). I could have the service app login as the user - which will be my fall back - but I'd like to know how the LocalSystem that it's logged in as can determine the current user.

All the GetCurrentUser routines I've found work only for standard apps.

 

[whosrdaddy]

this is not so easy. You could have a situation where you have more than 1 user logged in, how are you going to deal with such situations?

I found some C++ code on the net which does exactly this, returning a list of logged on users:

Use

//--------------------------------------------------------------------
//
// DisplayLocalLogons
// 
// Scans the HKEY_USERS key of the specified computer to see who
// has their profile loaded. Returns true if someone is logged on.
//
//--------------------------------------------------------------------
BOOLEAN DisplayLocalLogons( LPWSTR ServerName, LPWSTR UserName  )
{
    BOOLEAN          first = TRUE;
   TCHAR          errorMessage[1024];
   TCHAR          userName[MAX_NAME_STRING], domainName[MAX_NAME_STRING];
   TCHAR          subKeyName[MAX_PATH];
   DWORD          subKeyNameSize, index;
   DWORD          userNameSize, domainNameSize;
   FILETIME     lastWriteTime;
   HKEY          usersKey;
   PSID          sid;
   SID_NAME_USE sidType;
   SID_IDENTIFIER_AUTHORITY authority;
    BYTE          subAuthorityCount;
   DWORD          authorityVal, revision;
   DWORD          subAuthorityVal[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
   
   //
   // Use RegConnectRegistry so that we work with remote computers
   //
    if( ServerName ) {
         
         wprintf(L"Connecting to Registry of %s...", ServerName );
         fflush( stdout );

         if( RegConnectRegistry( ServerName, HKEY_USERS, &usersKey ) != ERROR_SUCCESS) {
       
              wprintf(L"\r                                                      \r");
              wprintf( L"Error opening HKEY_USERS for %s\n", ServerName );
              return FALSE;
         }
         wprintf(L"\r                                                      \r");

    } else {

         if( RegOpenKey( HKEY_USERS, NULL, &usersKey ) != ERROR_SUCCESS ) {

              wprintf( errorMessage, L"Error opening HKEY_USERS" );
              PrintWin32Error( errorMessage, GetLastError() );
              return FALSE;
         }
    }
  
    //
   // Enumerate keys under HKEY_USERS
   //
   index = 0;
   subKeyNameSize = sizeof( subKeyName );
   while( RegEnumKeyEx( usersKey, index, subKeyName, &subKeyNameSize,
                        NULL, NULL, NULL, &lastWriteTime ) == ERROR_SUCCESS ) {

       //
       // Ignore the default subkey and win2K user class subkeys
       //
       if( wcsicmp( subKeyName, L".default" ) &&
              !wcsstr( subKeyName, L"Classes")) {

              //
              // Convert the textual SID into a binary SID
              //
           subAuthorityCount= swscanf( subKeyName, L"S-%d-%x-%lu-%lu-%lu-%lu-%lu-%lu-%lu-%lu",
                                       &revision, &authorityVal,
                                       &subAuthorityVal[0],
                                       &subAuthorityVal[1],
                                       &subAuthorityVal[2],
                                       &subAuthorityVal[3],
                                       &subAuthorityVal[4],
                                       &subAuthorityVal[5],
                                       &subAuthorityVal[6],
                                       &subAuthorityVal[7] );

           if( subAuthorityCount >= 3 ) {

               subAuthorityCount -= 2;
               
               //
               // Note: we can only deal with authority values
               // of 4 bytes in length
               //
               authority.Value[5] = *(PBYTE) &authorityVal;
               authority.Value[4] = *((PBYTE) &authorityVal+1);
               authority.Value[3] = *((PBYTE) &authorityVal+2);
               authority.Value[2] = *((PBYTE) &authorityVal+3);
               authority.Value[1] = 0;
               authority.Value[0] = 0;

                   //
               // Initialize variables for subsequent operations
               //
               sid = NULL;
               userNameSize   = MAX_NAME_STRING;
               domainNameSize = MAX_NAME_STRING;

               if( AllocateAndInitializeSid( &authority,
                                              subAuthorityCount,
                                              subAuthorityVal[0],
                                              subAuthorityVal[1],
                                              subAuthorityVal[2],
                                              subAuthorityVal[3],
                                              subAuthorityVal[4],
                                              subAuthorityVal[5],
                                              subAuthorityVal[6],
                                              subAuthorityVal[7],
                                              &sid )) {

                        //
                        // We can finally lookup the account name
                        //
                        if( LookupAccountSid( ServerName,
                                                   sid, 
                                                    userName,
                                                   &userNameSize,
                                                   domainName,
                                                   &domainNameSize,
                                                   &sidType )) {

                             //
                             // We've successfully looked up the user name
                             //
                           if( first && !UserName ) {
                                
                                   wprintf(L"Users logged on locally:\n");
                                  first = FALSE;
                           }
                           if( !UserName || !wcsicmp( UserName, userName )) {
                             
                                first = FALSE;
                                if( UserName ) wprintf(RESETLINE L"%s\\%s logged onto %s locally.\n", 
                                                                 domainName, UserName, ServerName );
                                else                 wprintf( L"     %s\\%s\n", domainName, userName );
                           }                               
                         }
               }               
                if( sid ) FreeSid( sid );
           }
       }
       subKeyNameSize = sizeof( subKeyName );
       index++;
   }
    RegCloseKey( usersKey );

    if( first && !UserName ) wprintf(L"No one is logged on locally.\n");
    return !first;
}

I can help you with translating to delphi if needed.

/Daddy

-----------------------------------------------------
What You See Is What You Get
Never underestimate tha powah of tha google!

 

[whosrdaddy]

found another way on torry's:

http://www.swissdelphicenter.ch/torry/showcode.php?id=966

/Daddy

-----------------------------------------------------
What You See Is What You Get
Never underestimate tha powah of tha google!

 

[Griffyn]

four eyes are better than two. I'm sure I'll be able to get what I need working with those.

Thanks Daddy!