Clients/ExplorerPlugin/ExplorerPlugin.cpp

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  *
   3  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
   4  *
   5  * Licensed under the Apache License, Version 2.0 (the "License");
   6  * you may not use this file except in compliance with the License.
   7  * You may obtain a copy of the License at
   8  *
   9  *     http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  */
  17
  18 #include        "StdAfx.h"
  19
  20 // The following 2 includes have to be in this order and INITGUID must be defined here, before including the file
  21 // that specifies the GUID(s), and nowhere else. The reason for this is that initguid.h doesn't provide separate
  22 // define and declare macros for GUIDs so you have to #define INITGUID in the single file where you want to define
  23 // your GUID then in all the other files that just need the GUID declared, INITGUID must not be defined.
  24
  25 #define INITGUID
  26 #include        <initguid.h>
  27 #include        "ExplorerPlugin.h"
  28
  29 #include        <comcat.h>
  30 #include        <Shlwapi.h>
  31
  32 #include        "CommonServices.h"
  33 #include        "DebugServices.h"
  34
  35 #include        "ClassFactory.h"
  36 #include        "Resource.h"
  37
  38 #include        "loclibrary.h"
  39
  40 // MFC Debugging
  41
  42 #ifdef _DEBUG
  43 #define new DEBUG_NEW
  44 #undef THIS_FILE
  45 static char THIS_FILE[] = __FILE__;
  46 #endif
  47
  48 #if 0
  49 #pragma mark == Prototypes ==
  50 #endif
  51
  52 //===========================================================================================================================
  53 //      Prototypes
  54 //===========================================================================================================================
  55
  56 // Utilities
  57
  58 DEBUG_LOCAL OSStatus    RegisterServer( HINSTANCE inInstance, CLSID inCLSID, LPCTSTR inName );
  59 DEBUG_LOCAL OSStatus    RegisterCOMCategory( CLSID inCLSID, CATID inCategoryID, BOOL inRegister );
  60 DEBUG_LOCAL OSStatus    UnregisterServer( CLSID inCLSID );
  61 DEBUG_LOCAL OSStatus    MyRegDeleteKey( HKEY hKeyRoot, LPTSTR lpSubKey );
  62
  63 // Stash away pointers to our resource DLLs
  64
  65 static HINSTANCE g_nonLocalizedResources        = NULL;
  66 static CString   g_nonLocalizedResourcesName;
  67 static HINSTANCE g_localizedResources           = NULL;
  68
  69 HINSTANCE
  70 GetNonLocalizedResources()
  71 {
  72         return g_nonLocalizedResources;
  73 }
  74
  75 HINSTANCE
  76 GetLocalizedResources()
  77 {
  78         return g_localizedResources;
  79 }
  80
  81 // This is the class GUID for an undocumented hook into IE that will allow us to register
  82 // and have IE notice our new ExplorerBar without rebooting.
  83 // {8C7461EF-2B13-11d2-BE35-3078302C2030}
  84
  85 DEFINE_GUID(CLSID_CompCatCacheDaemon,
  86 0x8C7461EF, 0x2b13, 0x11d2, 0xbe, 0x35, 0x30, 0x78, 0x30, 0x2c, 0x20, 0x30);
  87
  88
  89 #if 0
  90 #pragma mark == Globals ==
  91 #endif
  92
  93 //===========================================================================================================================
  94 //      Globals
  95 //===========================================================================================================================
  96
  97 HINSTANCE                       gInstance               = NULL;
  98 int                                     gDLLRefCount    = 0;
  99 CExplorerPluginApp      gApp;
 100
 101 #if 0
 102 #pragma mark -
 103 #pragma mark == DLL Exports ==
 104 #endif
 105
 106 //===========================================================================================================================
 107 //      CExplorerPluginApp::CExplorerPluginApp
 108 //===========================================================================================================================
 109
 110 IMPLEMENT_DYNAMIC(CExplorerPluginApp, CWinApp);
 111
 112 CExplorerPluginApp::CExplorerPluginApp()
 113 {
 114 }
 115
 116
 117 //===========================================================================================================================
 118 //      CExplorerPluginApp::~CExplorerPluginApp
 119 //===========================================================================================================================
 120
 121 CExplorerPluginApp::~CExplorerPluginApp()
 122 {
 123 }
 124
 125
 126 //===========================================================================================================================
 127 //      CExplorerPluginApp::InitInstance
 128 //===========================================================================================================================
 129
 130 BOOL
 131 CExplorerPluginApp::InitInstance()
 132 {
 133         wchar_t                                 resource[MAX_PATH];
 134         OSStatus                                err;
 135         int                                             res;
 136         HINSTANCE inInstance;
 137
 138         inInstance = AfxGetInstanceHandle();
 139         gInstance = inInstance;
 140
 141         debug_initialize( kDebugOutputTypeWindowsEventLog, "DNSServices Bar", inInstance );
 142         debug_set_property( kDebugPropertyTagPrintLevel, kDebugLevelTrace );
 143         dlog( kDebugLevelTrace, "\nCCPApp::InitInstance\n" );
 144
 145         res = PathForResource( inInstance, L"ExplorerPluginResources.dll", resource, MAX_PATH );
 146
 147         err = translate_errno( res != 0, kUnknownErr, kUnknownErr );
 148         require_noerr( err, exit );
 149
 150         g_nonLocalizedResources = LoadLibrary( resource );
 151         translate_errno( g_nonLocalizedResources, GetLastError(), kUnknownErr );
 152         require_noerr( err, exit );
 153
 154         g_nonLocalizedResourcesName = resource;
 155
 156         res = PathForResource( inInstance, L"ExplorerPluginLocalized.dll", resource, MAX_PATH );
 157         err = translate_errno( res != 0, kUnknownErr, kUnknownErr );
 158         require_noerr( err, exit );
 159
 160         g_localizedResources = LoadLibrary( resource );
 161         translate_errno( g_localizedResources, GetLastError(), kUnknownErr );
 162         require_noerr( err, exit );
 163
 164         AfxSetResourceHandle( g_localizedResources );
 165
 166 exit:
 167
 168         return TRUE;
 169 }
 170
 171
 172 //===========================================================================================================================
 173 //      CExplorerPluginApp::ExitInstance
 174 //===========================================================================================================================
 175
 176 int
 177 CExplorerPluginApp::ExitInstance()
 178 {
 179         return 0;
 180 }
 181
 182
 183
 184 //===========================================================================================================================
 185 //      DllCanUnloadNow
 186 //===========================================================================================================================
 187
 188 STDAPI  DllCanUnloadNow( void )
 189 {
 190         dlog( kDebugLevelTrace, "DllCanUnloadNow (refCount=%d)\n", gDLLRefCount );
 191
 192         return( gDLLRefCount == 0 );
 193 }
 194
 195 //===========================================================================================================================
 196 //      DllGetClassObject
 197 //===========================================================================================================================
 198
 199 STDAPI  DllGetClassObject( REFCLSID inCLSID, REFIID inIID, LPVOID *outResult )
 200 {
 201         HRESULT                         err;
 202         BOOL                            ok;
 203         ClassFactory *          factory;
 204
 205         dlog( kDebugLevelTrace, "DllGetClassObject\n" );
 206
 207         *outResult = NULL;
 208
 209         // Check if the class ID is supported.
 210
 211         ok = IsEqualCLSID( inCLSID, CLSID_ExplorerBar );
 212         require_action_quiet( ok, exit, err = CLASS_E_CLASSNOTAVAILABLE );
 213
 214         // Create the ClassFactory object.
 215
 216         factory = NULL;
 217         try
 218         {
 219                 factory = new ClassFactory( inCLSID );
 220         }
 221         catch( ... )
 222         {
 223                 // Do not let exception escape.
 224         }
 225         require_action( factory, exit, err = E_OUTOFMEMORY );
 226
 227         // Query for the specified interface. Release the factory since QueryInterface retains it.
 228
 229         err = factory->QueryInterface( inIID, outResult );
 230         factory->Release();
 231
 232 exit:
 233         return( err );
 234 }
 235
 236 //===========================================================================================================================
 237 //      DllRegisterServer
 238 //===========================================================================================================================
 239
 240 STDAPI  DllRegisterServer( void )
 241 {
 242         IRunnableTask * pTask = NULL;
 243         HRESULT                 err;
 244         BOOL                    ok;
 245         CString                 s;
 246
 247         dlog( kDebugLevelTrace, "DllRegisterServer\n" );
 248
 249         ok = s.LoadString( IDS_NAME );
 250         require_action( ok, exit, err = E_UNEXPECTED );
 251
 252         err = RegisterServer( gInstance, CLSID_ExplorerBar, s );
 253         require_noerr( err, exit );
 254
 255         err = RegisterCOMCategory( CLSID_ExplorerBar, CATID_InfoBand, TRUE );
 256         require_noerr( err, exit );
 257
 258         // <rdar://problem/4130635> Clear IE cache so it will rebuild the cache when it runs next.  This
 259         // will allow us to install and not reboot
 260
 261         err = CoCreateInstance(CLSID_CompCatCacheDaemon, NULL, CLSCTX_INPROC, IID_IRunnableTask, (void**) &pTask);
 262         require_noerr( err, exit );
 263
 264         pTask->Run();
 265         pTask->Release();
 266
 267 exit:
 268         return( err );
 269 }
 270
 271 //===========================================================================================================================
 272 //      DllUnregisterServer
 273 //===========================================================================================================================
 274
 275 STDAPI  DllUnregisterServer( void )
 276 {
 277         HRESULT         err;
 278
 279         dlog( kDebugLevelTrace, "DllUnregisterServer\n" );
 280
 281         err = RegisterCOMCategory( CLSID_ExplorerBar, CATID_InfoBand, FALSE );
 282         require_noerr( err, exit );
 283
 284         err = UnregisterServer( CLSID_ExplorerBar );
 285         require_noerr( err, exit );
 286
 287 exit:
 288         return( err );
 289 }
 290
 291
 292 #if 0
 293 #pragma mark -
 294 #pragma mark == Utilities ==
 295 #endif
 296
 297 //===========================================================================================================================
 298 //      RegisterServer
 299 //===========================================================================================================================
 300
 301 DEBUG_LOCAL OSStatus    RegisterServer( HINSTANCE inInstance, CLSID inCLSID, LPCTSTR inName )
 302 {
 303         typedef struct  RegistryBuilder         RegistryBuilder;
 304         struct  RegistryBuilder
 305         {
 306                 HKEY            rootKey;
 307                 LPCTSTR         subKey;
 308                 LPCTSTR         valueName;
 309                 LPCTSTR         data;
 310         };
 311
 312         OSStatus                        err;
 313         LPWSTR                          clsidWideString;
 314         TCHAR                           clsidString[ 64 ];
 315         DWORD                           nChars;
 316         size_t                          n;
 317         size_t                          i;
 318         HKEY                            key;
 319         TCHAR                           keyName[ MAX_PATH ];
 320         TCHAR                           moduleName[ MAX_PATH ] = TEXT( "" );
 321         TCHAR                           data[ MAX_PATH ];
 322         RegistryBuilder         entries[] =
 323         {
 324                 { HKEY_CLASSES_ROOT,    TEXT( "CLSID\\%s" ),                                    NULL,                                           inName },
 325                 { HKEY_CLASSES_ROOT,    TEXT( "CLSID\\%s\\InprocServer32" ),    NULL,                                           moduleName },
 326                 { HKEY_CLASSES_ROOT,    TEXT( "CLSID\\%s\\InprocServer32" ),    TEXT( "ThreadingModel" ),       TEXT( "Apartment" ) }
 327         };
 328         DWORD                           size;
 329         OSVERSIONINFO           versionInfo;
 330
 331         // Convert the CLSID to a string based on the encoding of this code (ANSI or Unicode).
 332
 333         err = StringFromIID( inCLSID, &clsidWideString );
 334         require_noerr( err, exit );
 335         require_action( clsidWideString, exit, err = kNoMemoryErr );
 336
 337         #ifdef UNICODE
 338                 lstrcpyn( clsidString, clsidWideString, sizeof_array( clsidString ) );
 339                 CoTaskMemFree( clsidWideString );
 340         #else
 341                 nChars = WideCharToMultiByte( CP_ACP, 0, clsidWideString, -1, clsidString, sizeof_array( clsidString ), NULL, NULL );
 342                 err = translate_errno( nChars > 0, (OSStatus) GetLastError(), kUnknownErr );
 343                 CoTaskMemFree( clsidWideString );
 344                 require_noerr( err, exit );
 345         #endif
 346
 347         // Register the CLSID entries.
 348
 349         nChars = GetModuleFileName( inInstance, moduleName, sizeof_array( moduleName ) );
 350         err = translate_errno( nChars > 0, (OSStatus) GetLastError(), kUnknownErr );
 351         require_noerr( err, exit );
 352
 353         n = sizeof_array( entries );
 354         for( i = 0; i < n; ++i )
 355         {
 356                 wsprintf( keyName, entries[ i ].subKey, clsidString );
 357                 err = RegCreateKeyEx( entries[ i ].rootKey, keyName, 0, NULL, REG_OPTION_NON_VOLATILE, KEY_WRITE, NULL, &key, NULL );
 358                 require_noerr( err, exit );
 359
 360                 size = (DWORD)( ( lstrlen( entries[ i ].data ) + 1 ) * sizeof( TCHAR ) );
 361                 err = RegSetValueEx( key, entries[ i ].valueName, 0, REG_SZ, (LPBYTE) entries[ i ].data, size );
 362                 RegCloseKey( key );
 363                 require_noerr( err, exit );
 364         }
 365
 366         // If running on NT, register the extension as approved.
 367
 368         versionInfo.dwOSVersionInfoSize = sizeof( versionInfo );
 369         GetVersionEx( &versionInfo );
 370         if( versionInfo.dwPlatformId == VER_PLATFORM_WIN32_NT )
 371         {
 372                 lstrcpyn( keyName, TEXT( "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Shell Extensions\\Approved" ), sizeof_array( keyName ) );
 373                 err = RegCreateKeyEx( HKEY_LOCAL_MACHINE, keyName, 0, NULL, REG_OPTION_NON_VOLATILE, KEY_WRITE, NULL, &key, NULL );
 374                 require_noerr( err, exit );
 375
 376                 lstrcpyn( data, inName, sizeof_array( data ) );
 377                 size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 378                 err = RegSetValueEx( key, clsidString, 0, REG_SZ, (LPBYTE) data, size );
 379                 RegCloseKey( key );
 380         }
 381
 382         // register toolbar button
 383         lstrcpyn( keyName, TEXT( "SOFTWARE\\Microsoft\\Internet Explorer\\Extensions\\{7F9DB11C-E358-4ca6-A83D-ACC663939424}"), sizeof_array( keyName ) );
 384         err = RegCreateKeyEx( HKEY_LOCAL_MACHINE, keyName, 0, NULL, REG_OPTION_NON_VOLATILE, KEY_WRITE, NULL, &key, NULL );
 385         require_noerr( err, exit );
 386
 387         lstrcpyn( data, L"Yes", sizeof_array( data ) );
 388         size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 389         RegSetValueEx( key, L"Default Visible", 0, REG_SZ, (LPBYTE) data, size );
 390
 391         lstrcpyn( data, inName, sizeof_array( data ) );
 392         size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 393         RegSetValueEx( key, L"ButtonText", 0, REG_SZ, (LPBYTE) data, size );
 394
 395         lstrcpyn( data, L"{E0DD6CAB-2D10-11D2-8F1A-0000F87ABD16}", sizeof_array( data ) );
 396         size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 397         RegSetValueEx( key, L"CLSID", 0, REG_SZ, (LPBYTE) data, size );
 398
 399         lstrcpyn( data, clsidString, sizeof_array( data ) );
 400         size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 401         RegSetValueEx( key, L"BandCLSID", 0, REG_SZ, (LPBYTE) data, size );
 402
 403         // check if we're running XP or later
 404         if ( ( versionInfo.dwPlatformId == VER_PLATFORM_WIN32_NT ) &&
 405                  ( versionInfo.dwMajorVersion == 5 ) &&
 406              ( versionInfo.dwMinorVersion >= 1 ) )
 407         {
 408                 wsprintf( data, L"%s,%d", (LPCTSTR) g_nonLocalizedResourcesName, IDI_BUTTON_XP );
 409                 size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 410                 RegSetValueEx( key, L"Icon", 0, REG_SZ, (LPBYTE) data, size);
 411
 412                 wsprintf( data, L"%s,%d", (LPCTSTR) g_nonLocalizedResourcesName, IDI_BUTTON_XP );
 413                 size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 414                 RegSetValueEx( key, L"HotIcon", 0, REG_SZ, (LPBYTE) data, size);
 415         }
 416         else
 417         {
 418                 wsprintf( data, L"%s,%d", (LPCTSTR) g_nonLocalizedResourcesName, IDI_BUTTON_2K );
 419                 size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 420                 RegSetValueEx( key, L"Icon", 0, REG_SZ, (LPBYTE) data, size);
 421
 422                 wsprintf( data, L"%s,%d", (LPCTSTR) g_nonLocalizedResourcesName, IDI_BUTTON_2K );
 423                 size = (DWORD)( ( lstrlen( data ) + 1 ) * sizeof( TCHAR ) );
 424                 RegSetValueEx( key, L"HotIcon", 0, REG_SZ, (LPBYTE) data, size);
 425         }
 426
 427         RegCloseKey( key );
 428
 429 exit:
 430         return( err );
 431 }
 432
 433 //===========================================================================================================================
 434 //      RegisterCOMCategory
 435 //===========================================================================================================================
 436
 437 DEBUG_LOCAL OSStatus    RegisterCOMCategory( CLSID inCLSID, CATID inCategoryID, BOOL inRegister )
 438 {
 439         HRESULT                         err;
 440         ICatRegister *          cat;
 441
 442         err = CoInitialize( NULL );
 443         require( SUCCEEDED( err ), exit );
 444
 445         err = CoCreateInstance( CLSID_StdComponentCategoriesMgr, NULL, CLSCTX_INPROC_SERVER, IID_ICatRegister, (LPVOID *) &cat );
 446         check( SUCCEEDED( err ) );
 447         if( SUCCEEDED( err ) )
 448         {
 449                 if( inRegister )
 450                 {
 451                         err = cat->RegisterClassImplCategories( inCLSID, 1, &inCategoryID );
 452                         check_noerr( err );
 453                 }
 454                 else
 455                 {
 456                         err = cat->UnRegisterClassImplCategories( inCLSID, 1, &inCategoryID );
 457                         check_noerr( err );
 458                 }
 459                 cat->Release();
 460         }
 461         CoUninitialize();
 462
 463 exit:
 464         return( err );
 465 }
 466
 467
 468 //===========================================================================================================================
 469 //      UnregisterServer
 470 //===========================================================================================================================
 471
 472 DEBUG_LOCAL OSStatus    UnregisterServer( CLSID inCLSID )
 473 {
 474         OSStatus                        err = 0;
 475         LPWSTR                          clsidWideString;
 476         TCHAR                           clsidString[ 64 ];
 477         HKEY                            key;
 478         TCHAR                           keyName[ MAX_PATH * 2 ];
 479         OSVERSIONINFO           versionInfo;
 480
 481         // Convert the CLSID to a string based on the encoding of this code (ANSI or Unicode).
 482
 483         err = StringFromIID( inCLSID, &clsidWideString );
 484         require_noerr( err, exit );
 485         require_action( clsidWideString, exit, err = kNoMemoryErr );
 486
 487         #ifdef UNICODE
 488                 lstrcpyn( clsidString, clsidWideString, sizeof_array( clsidString ) );
 489                 CoTaskMemFree( clsidWideString );
 490         #else
 491                 nChars = WideCharToMultiByte( CP_ACP, 0, clsidWideString, -1, clsidString, sizeof_array( clsidString ), NULL, NULL );
 492                 err = translate_errno( nChars > 0, (OSStatus) GetLastError(), kUnknownErr );
 493                 CoTaskMemFree( clsidWideString );
 494                 require_noerr( err, exit );
 495         #endif
 496
 497         wsprintf( keyName, L"CLSID\\%s", clsidString );
 498         MyRegDeleteKey( HKEY_CLASSES_ROOT, keyName );
 499
 500         // If running on NT, de-register the extension as approved.
 501
 502         versionInfo.dwOSVersionInfoSize = sizeof( versionInfo );
 503         GetVersionEx( &versionInfo );
 504         if( versionInfo.dwPlatformId == VER_PLATFORM_WIN32_NT )
 505         {
 506                 lstrcpyn( keyName, TEXT( "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Shell Extensions\\Approved" ), sizeof_array( keyName ) );
 507                 err = RegCreateKeyEx( HKEY_LOCAL_MACHINE, keyName, 0, NULL, REG_OPTION_NON_VOLATILE, KEY_WRITE, NULL, &key, NULL );
 508                 require_noerr( err, exit );
 509
 510                 RegDeleteValue( key, clsidString );
 511
 512                 err = RegCloseKey( key );
 513                 require_noerr( err, exit );
 514         }
 515
 516         // de-register toolbar button
 517
 518         lstrcpyn( keyName, TEXT( "SOFTWARE\\Microsoft\\Internet Explorer\\Extensions\\{7F9DB11C-E358-4ca6-A83D-ACC663939424}"), sizeof_array( keyName ) );
 519         MyRegDeleteKey( HKEY_LOCAL_MACHINE, keyName );
 520
 521 exit:
 522         return( err );
 523 }
 524
 525
 526
 527 //===========================================================================================================================
 528 //      MyRegDeleteKey
 529 //===========================================================================================================================
 530
 531 DEBUG_LOCAL OSStatus MyRegDeleteKey( HKEY hKeyRoot, LPTSTR lpSubKey )
 532 {
 533     LPTSTR lpEnd;
 534     OSStatus err;
 535     DWORD dwSize;
 536     TCHAR szName[MAX_PATH];
 537     HKEY hKey;
 538     FILETIME ftWrite;
 539
 540     // First, see if we can delete the key without having to recurse.
 541
 542     err = RegDeleteKey( hKeyRoot, lpSubKey );
 543
 544     if ( !err )
 545         {
 546                 goto exit;
 547         }
 548
 549     err = RegOpenKeyEx( hKeyRoot, lpSubKey, 0, KEY_READ, &hKey );
 550         require_noerr( err, exit );
 551
 552     // Check for an ending slash and add one if it is missing.
 553
 554     lpEnd = lpSubKey + lstrlen(lpSubKey);
 555
 556     if ( *( lpEnd - 1 ) != TEXT( '\\' ) )
 557     {
 558         *lpEnd =  TEXT('\\');
 559         lpEnd++;
 560         *lpEnd =  TEXT('\0');
 561     }
 562
 563     // Enumerate the keys
 564
 565     dwSize = MAX_PATH;
 566     err = RegEnumKeyEx(hKey, 0, szName, &dwSize, NULL, NULL, NULL, &ftWrite);
 567
 568     if ( !err )
 569     {
 570         do
 571                 {
 572             lstrcpy (lpEnd, szName);
 573
 574             if ( !MyRegDeleteKey( hKeyRoot, lpSubKey ) )
 575                         {
 576                 break;
 577             }
 578
 579             dwSize = MAX_PATH;
 580
 581             err = RegEnumKeyEx( hKey, 0, szName, &dwSize, NULL, NULL, NULL, &ftWrite );
 582
 583         }
 584                 while ( !err );
 585     }
 586
 587     lpEnd--;
 588     *lpEnd = TEXT('\0');
 589
 590     RegCloseKey( hKey );
 591
 592     // Try again to delete the key.
 593
 594     err = RegDeleteKey(hKeyRoot, lpSubKey);
 595         require_noerr( err, exit );
 596
 597 exit:
 598
 599         return err;
 600 }