Fix regression of launching notepad++.exe with admin privilege

Fix notepad-plus-plus/notepad-plus-plus#17540 (comment)

Author: donho

src/Common.cpp

@@ -262,3 +262,23 @@ wstring stringReplace(wstring subject, const wstring& search, const wstring& rep
 	}
 	return subject;
 }
+
+void safeLaunchAsUser(const std::wstring& prog2Launch)
+{
+	wchar_t winDir[MAX_PATH];
+	if (GetWindowsDirectory(winDir, MAX_PATH) == 0) return;
+	std::wstring explorerPath = std::wstring(winDir) + L"\\explorer.exe";
+
+	wchar_t prog2LaunchDir[MAX_PATH];
+	lstrcpy(prog2LaunchDir, prog2Launch.c_str());
+	::PathRemoveFileSpec(prog2LaunchDir);
+
+	::ShellExecute(
+		NULL,
+		L"open",
+		explorerPath.c_str(), // Trusted path
+		prog2Launch.c_str(),  // Target
+		prog2LaunchDir,
+		SW_SHOWNORMAL
+	);
+}

src/Common.h

@@ -65,3 +65,4 @@ std::wstring GetLastErrorAsString(DWORD errorCode);
 std::wstring stringToUpper(std::wstring strToConvert);
 std::wstring stringToLower(std::wstring strToConvert);
 std::wstring stringReplace(std::wstring subject, const std::wstring& search, const std::wstring& replace);
+void safeLaunchAsUser(const std::wstring& prog2Launch);

src/winmain.cpp

@@ -1469,9 +1469,6 @@ int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR lpszCmdLine, int)
 			return -1;
 		}
 		wstring prog2Launch = params[0];
-		wchar_t prog2LaunchDir[MAX_PATH];
-		lstrcpy(prog2LaunchDir, prog2Launch.c_str());
-		::PathRemoveFileSpec(prog2LaunchDir);
 		wstring destPathRoot = params[1];
 
 #ifdef _DEBUG
@@ -1502,7 +1499,7 @@ int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR lpszCmdLine, int)
 			deleteFileOrFolder(destPath);
 		}
 
-		::ShellExecute(NULL, L"open", prog2Launch.c_str(), NULL, prog2LaunchDir, SW_SHOWNORMAL);
+		safeLaunchAsUser(prog2Launch);
 
 		return 0;
 	}
@@ -1654,7 +1651,7 @@ int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR lpszCmdLine, int)
 			}
 		}
 
-		::ShellExecute(NULL, L"open", prog2Launch.c_str(), NULL, prog2LaunchDir, SW_SHOWNORMAL);
+		safeLaunchAsUser(prog2Launch);
 
 		return 0;
 	}