Specify the registry uninstall key location/hive via [Code] - inno-setup

Question

Inno Setup by default looks at the PrivilegesRequired setup variable, if this is set to admin or poweruser, the installer installs the uninstall registry key to HKLM. If this is set to lowest, then it will install the registry entries to HKCU.
I have a requirement to provide the user an option to install for "just me" or "everybody", and have done so by replacing the dir selection page with a radio selection of these two options. what I need to do now is also modify the registry install location based on this setting. If I install the app into the local user app data, it won't make sense to register the uninstall data at the HKLM level, because then other users will see it in the programs list and still be unable to uninstall or use it.
Edit: After looking through the documentation and the source of Install.pas, I found the CreateUninstallRegKey setup directive, which will disable Inno from installing registry keys at all, after which I can add my own registry entries, but is this really the only way?
Edit #2 (marked as duplicate): I've already taken a look at this Conditional Elevation question (and actually implemented it), and it's not the same as mine. The current elevation state does not alter where Inno Setup actually saves the uninstall registry info (in HKCU or HKLM). If you look at the Inno source code (Install.pas #507) you'll see that the PrivilegesRequired directive is the primary factor in where the registry is stored. If this is set to lowest, it doesnt matter if the installer is elevated or not - it will install the registry keys to HKCU, when the desired behavior is to select one or the other based on the users install preference, NOT the current elevation state. So all this being said, I'm looking for a solution to alter the registry root based on a code variable, regardless of current PrivilegesRequired or Elevation setting.

Answer 1

Inno Setup 6 has a built-in support for selecting between "Install for all users" and "Install for me only".
Basically, you can simply set PrivilegesRequiredOverridesAllowed:
[Setup]
PrivilegesRequiredOverridesAllowed=commandline dialog
For Inno Setup 5: As you found yourself, the logic is hard-coded. You cannot really control that.
The closest you can get is by using the undocumented (deprecated) PrivilegesRequired=none.
With this value (and with a help of installer-autodetection in Windows):
When you start the installer with an un-privileged account, it starts without prompting you for elevation. If you decide you need to elevate during the installation, you can restart the installer elevated.
When you start the installer with a privileged account, it always prompts you for elevation and won't start, if you reject that. So the installer always runs elevated. Again, you would have to restart the installer, if you decide you to proceed un-elevated. See How to Start a Process Unelevated or maybe Run un-elevated command from an elevated prompt?.
It's not exactly, what you want, but I do not think you can get any closer.
You can of course copy (move) the registry key between the HKCU and HKLM yourself by a code:
function MoveHKCUUninstallKeyToHKLM: Boolean;
var
UninstallKey: string;
AppId: string;
I: Integer;
ValueNames: TArrayOfString;
ValueName: string;
ValueStr: string;
ValueDWord: Cardinal;
begin
if '{#emit SetupSetting("AppId")}' <> '' then
begin
AppId := '{#emit SetupSetting("AppId")}';
end
else
begin
AppId := '{#emit SetupSetting("AppName")}';
end;
Result := False;
if AppId = '' then
begin
Log('Cannot identify AppId');
end
else
begin
UninstallKey :=
'Software\Microsoft\Windows\CurrentVersion\Uninstall\' + AppId + '_is1';
Log(Format(
'AppId identified as "%s", using uninstall key "%s"', [AppId, UninstallKey]));
if not RegKeyExists(HKCU, UninstallKey) then
begin
Log('HKCU uninstall key not found');
end
else
if RegKeyExists(HKLM, UninstallKey) then
begin
Log('HKLM uninstall key exists already');
end
else
begin
Log('HKCU uninstall key found and HKLM key not exists yet');
if not RegGetValueNames(HKCU, UninstallKey, ValueNames) then
begin
Log('Cannot list uninstall key values');
end
else
begin
I := 0;
Result := True;
while (I < GetArrayLength(ValueNames)) and Result do
begin
ValueName := ValueNames[I];
if RegQueryStringValue(HKCU, UninstallKey, ValueName, ValueStr) then
begin
if not RegWriteStringValue(HKLM, UninstallKey, ValueName, ValueStr) then
begin
Log(Format('Error moving "%s" string value', [ValueName]));
Result := False;
end
else
begin
Log(Format('Moved "%s" string value', [ValueName]));
end;
end
else
if RegQueryDWordValue(HKCU, UninstallKey, ValueName, ValueDWord) then
begin
if not RegWriteDWordValue(HKLM, UninstallKey, ValueName, ValueDWord) then
begin
Log(Format('Error moving "%s" dword value', [ValueName]));
Result := False;
end
else
begin
Log(Format('Moved "%s" dword value', [ValueName]));
end;
end
else
begin
{ All uninstall values written by Inno Setup are either string or dword }
Log(Format('Value "%s" is neither string nor dword', [ValueName]));
Result := False;
end;
Inc(I);
end;
if Result then
begin
if not RegDeleteKeyIncludingSubkeys(HKCU, UninstallKey) then
begin
Log('Error removing HKCU uninstall key');
Result := False;
end
else
begin
Log('Removed HKCU uninstall key');
end;
end;
if not Result then
begin
if not RegDeleteKeyIncludingSubkeys(HKCU, UninstallKey) then
begin
Log('Failed to move uninstall key to HKLM, ' +
'and also failed to rollback the changes');
end
else
begin
Log('Failed to move uninstall key to HKLM, rolled back the changes');
end;
end;
end;
end;
end;
end;
procedure CurStepChanged(CurStep: TSetupStep);
begin
if CurStep = ssPostInstall then
begin
Log('Post install');
MoveHKCUUninstallKeyToHKLM;
end;
end;

Answer 2

The PrivilegesRequired=none solution was not what I wanted. In some cases, it still prompts for elevation on administrator accounts and also the registry destination was still not reflective of the users selection.
Since I was already using a native helper DLL in my Inno Setup project, I coded this in C++ as I'm more comfortable there. I'm calling this method is called in CurStepChanged where CurPage=ssDoneInstall. Just call this method with the [Setup] AppId and whether or not the registry keys should be installed locally or not.
#include <shlwapi.h>
extern "C" __declspec(dllexport)
bool DetectAndMoveRegKeyW(LPCWSTR app_id, bool install_local)
{
std::wstring s_app = app_id;
std::wstring path =
L"Software\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\" + s_app + L"_is1";
LPCWSTR c_path = path.c_str();
LRESULT res;
HKEY source = nullptr, subKey = nullptr;
// try to find source in HKLM
source = HKEY_LOCAL_MACHINE;
res = RegOpenKeyExW(source, c_path, 0, KEY_READ, &subKey);
if (subKey != nullptr)
RegCloseKey(subKey);
// try to find source in HKCU
if (res != ERROR_SUCCESS)
{
subKey = nullptr;
source = HKEY_CURRENT_USER;
res = RegOpenKeyExW(source, c_path, 0, KEY_READ, &subKey);
if (subKey != nullptr)
RegCloseKey(subKey);
}
if (res != ERROR_SUCCESS)
return false; // cant find the registry key
HKEY dest = install_local ? HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE;
if (source == dest)
return true; // registry already in the right place
// copy registry key to correct destination
HKEY hOldKey;
HKEY hNewKey;
bool bResult = false;
if (RegOpenKeyW(source, c_path, &hOldKey) == 0)
{
if (RegCreateKeyW(dest, c_path, &hNewKey) == 0)
{
bResult = (SHCopyKeyW(hOldKey, nullptr, hNewKey, 0) == 0);
RegCloseKey(hNewKey);
}
RegCloseKey(hOldKey);
if (bResult)
{
RegDeleteKeyW(source, c_path);
}
}
return bResult;
}
I'm exporting this method as cdecl instead of stdcall, this is because VC++ ignores the C extern and mangles method names anyways when using stdcall. You'll need to import this as cdecl in inno (see inno docs for this). Also, of course this is the Unicode-only implementation, if you require an Ansi version it should be simple enough.
IMPORTANT NOTICE:
This code is incomplete, it doesn't account for 64bit registry redirection. Inno-Setup completely ignores windows registry redirection and this code doesn't search the 64 bit registry at all since Inno and itself are running in 32bit.