Launch Windows Optimize application (Windows 10) from Delphi - windows

Question

We have a legacy Delphi 7 application that launches the Windows Defrag and On-screen Keyboard applications as follows:
// Defragmentation application
ShellExecute(0, 'open', PChar('C:\Windows\System32\dfrg.msc'), nil, nil, SW_SHOWNORMAL);
// On-screen keyboard
ShellExecute(0, 'open', PChar('C:\Windows\System32\osk.exe'), nil, nil, SW_SHOWNORMAL);
Both work on Windows XP but fail on Windows 10. I spotted that the defragmentation application has had a name change to dfrgui.exe, but updating the code does not help. The On-screen Keyboard is still called osk.exe on Windows 10.
Both applications can be launched manually / directly from the command line or by double-clicking them in Windows Explorer.
My suspicion is that Windows security is preventing my application from launching anything from C:\Windows\System32, because I can launch several other applications from Program Files and from C:\Windows.
Can anyone help?

Answer 1

Delphi 7 produces only 32-bit apps, there is no option to produce 64-bit apps (that was added in XE2).
Accessing a path under %WINDIR%\System32 from a 32-bit app running on a 64-bit system is subject to WOW64's File
System Redirector, which will silently redirect requests for the 64-bit System32 folder to the 32-bit SysWOW64 folder instead.
Chances are, the apps you are trying to run only exist in the 64-bit System32 folder and not in the 32-bit SysWOW64 folder.
To avoid redirection, you need to either:
replace System32 with the special Sysnative alias in your paths (ie 'C:\Windows\Sysnative\osk.exe'), which only works when running under WOW64, so you have to detect that dynamically at runtime via IsWow64Process():
function GetSystem32Folder: string;
var
Folder: array[0..MAX_PATH] of Char;
IsWow64: BOOL;
begin
Result := '';
if IsWow64Process(GetCurrentProcess(), #IsWow64) and IsWow64 then
begin
SetString(Result, Folder, GetWindowsDirectory(Folder, Length(Folder)));
if Result <> '' then
Result := IncludeTrailingPathDelimiter(Result) + 'Sysnative' + PathDelim;
end else
begin
SetString(Result, Folder, GetSystemDirectory(Folder, Length(Folder)));
if Result <> '' then
Result := IncludeTrailingPathDelimiter(Result);
end;
end;
function RunDefrag: Boolean;
var
SysFolder: string;
Res: Integer;
begin
SysFolder := GetSystem32Folder;
Res := Integer(ShellExecute(0, nil, PChar(SysFolder + 'dfrgui.exe'), nil, nil, SW_SHOWNORMAL));
if Res = ERROR_FILE_NOT_FOUND then
Res := Integer(ShellExecute(0, nil, PChar(SysFolder + 'dfrg.msc'), nil, nil, SW_SHOWNORMAL));
Result := (Res = 0);
end;
function RunOnScreenKeyboard: Boolean;
begin
Result := (ShellExecute(0, nil, PChar(GetSystem32Folder + 'osk.exe'), nil, nil, SW_SHOWNORMAL) = 0);
end;
temporarily disable the Redirector via Wow64DisableWow64FsRedirection(), and then re-enable it via Wow64RevertWow64FsRedirection() when done:
function GetSystem32Folder: string
var
Folder: array[0..MAX_PATH] of Char;
begin
SetString(Result, Folder, GetSystemDirectory(Folder, Length(Folder)));
if Result <> '' then
Result := IncludeTrailingPathDelimiter(Result);
end;
function RunDefrag: Boolean;
var
SysFolder: string;
OldState: Pointer;
Res: Integer;
begin
Wow64DisableWow64FsRedirection(#OldState);
try
SysFolder := GetSystem32Folder;
Res := Integer(ShellExecute(0, nil, PChar(SysFolder + 'dfrgui.exe'), nil, nil, SW_SHOWNORMAL));
if Res = ERROR_FILE_NOT_FOUND then
Res := Integer(ShellExecute(0, nil, PChar(SysFolder + 'dfrg.msc'), nil, nil, SW_SHOWNORMAL));
Result := Res = 0;
finally
Wow64RevertWow64FsRedirection(OldState);
end;
end;
function RunOnScreenKeyboard: Boolean;
var
OldState: Pointer;
begin
Wow64DisableWow64FsRedirection(#OldState);
try
Result := (ShellExecute(0, nil, PChar(GetSystem32Folder + 'osk.exe'), nil, nil, SW_SHOWNORMAL) = 0);
finally
Wow64RevertWow64FsRedirection(OldState);
end;
end;
Update: that being said, it turns out that a 32-bit process running under WOW64 is not allowed to run osk.exe when UAC is enabled:
Delphi - On Screen Keyboard (osk.exe) works on Win32 but fails on Win64
So, you will have to create a helper 64-bit process to launch osk.exe on your app's behalf when it is running under WOW64.

Answer 2

A small addition to Remy Lebeau's answer:
If Wow64DisableWow64FsRedirection is not available in your Delphi version, and/or if you are not sure if your target platform will support this API, you could use following code sample that calls the function dynamically:
https://www.delphipraxis.net/155861-windows-7-64bit-redirection.html
function ChangeFSRedirection(bDisable: Boolean): Boolean;
type
TWow64DisableWow64FsRedirection = Function(Var Wow64FsEnableRedirection: LongBool): LongBool; StdCall;
TWow64EnableWow64FsRedirection = Function(var Wow64FsEnableRedirection: LongBool): LongBool; StdCall;
var
hHandle: THandle;
Wow64DisableWow64FsRedirection: TWow64DisableWow64FsRedirection;
Wow64EnableWow64FsRedirection: TWow64EnableWow64FsRedirection;
Wow64FsEnableRedirection: LongBool;
begin
Result := false;
try
hHandle := GetModuleHandle('kernel32.dll');
#Wow64EnableWow64FsRedirection := GetProcAddress(hHandle, 'Wow64EnableWow64FsRedirection');
#Wow64DisableWow64FsRedirection := GetProcAddress(hHandle, 'Wow64DisableWow64FsRedirection');
if bDisable then
begin
if (hHandle <> 0) and (#Wow64DisableWow64FsRedirection <> nil) then
begin
Result := Wow64DisableWow64FsRedirection(Wow64FsEnableRedirection);
end;
end else
begin
if (hHandle <> 0) and (#Wow64EnableWow64FsRedirection <> nil) then
begin
Result := Wow64EnableWow64FsRedirection(Wow64FsEnableRedirection);
Result := True;
end;
end;
Except
end;
end;