main.cpp

#include "pch.h"
#include <Commdlg.h>
#include "StreamUriResolverFromFile.h"
#include <Shellapi.h>
#include <common/two_way_pipe_message_ipc.h>
#include <ShellScalingApi.h>
#include "resource.h"
#include <common/dpi_aware.h>
#include <common/common.h>
#include <Sddl.h>

#include "trace.h"

#pragma comment(lib, "shlwapi.lib")
#pragma comment(lib, "shcore.lib")
#pragma comment(lib, "windowsapp")

#ifdef _DEBUG
#define _DEBUG_WITH_LOCALHOST 0
// Define as 1 For debug purposes, to access localhost servers.
// webview_process_options.PrivateNetworkClientServerCapability(winrt::Windows::Web::UI::Interop::WebViewControlProcessCapabilityState::Enabled);
// To access localhost:8080 for development, you'll also need to disable loopback restrictions for the webview:
// > checknetisolation LoopbackExempt -a -n=Microsoft.Win32WebViewHost_cw5n1h2txyewy
// To remove the exception after development:
// > checknetisolation LoopbackExempt -d -n=Microsoft.Win32WebViewHost_cw5n1h2txyewy
// Source: https://github.com/windows-toolkit/WindowsCommunityToolkit/issues/2226#issuecomment-396360314
#endif

using namespace winrt;
using namespace winrt::Windows::Foundation;
using namespace winrt::Windows::Storage::Streams;
using namespace winrt::Windows::Web::Http;
using namespace winrt::Windows::Web::Http::Headers;
using namespace winrt::Windows::Web::UI;
using namespace winrt::Windows::Web::UI::Interop;
using namespace winrt::Windows::System;

HINSTANCE g_hinst = nullptr;
HWND g_main_wnd = nullptr;
WebViewControl g_webview = nullptr;
WebViewControlProcess g_webview_process = nullptr;

// Windows message for receiving copied data to send to the webview.
UINT wm_data_for_webview = 0;

// Windows message to destroy the window. Used if:
// - Parent process has terminated.
// - WebView confirms that the Window can close.
UINT wm_destroy_window = 0;

// Message pipe to send/receive messages to/from the Powertoys runner.
TwoWayPipeMessageIPC* g_message_pipe = nullptr;

// Set to true if waiting for webview confirmation before closing the Window.
bool g_waiting_for_close_confirmation = false;

// Is the setting window to be started in dark mode
bool g_start_in_dark_mode = false;

#ifdef _DEBUG
void NavigateToLocalhostReactServer()
{
    // Useful for connecting to instance running in react development server.
    g_webview.Navigate(Uri(hstring(L"http://localhost:8080")));
}
#endif

#define URI_CONTENT_ID L"\\settings-html"

void NavigateToUri(_In_ LPCWSTR uri_as_string)
{
    auto uri_resolver = winrt::make_self<StreamUriResolverFromFile>();
    // initialize the base_path for the html content relative to the executable.
    WINRT_VERIFY(GetModuleFileName(nullptr, uri_resolver->base_path, MAX_PATH));
    WINRT_VERIFY(PathRemoveFileSpec(uri_resolver->base_path));
    wcscat_s(uri_resolver->base_path, URI_CONTENT_ID);
    Uri url = g_webview.BuildLocalStreamUri(hstring(URI_CONTENT_ID), hstring(uri_as_string));
    g_webview.NavigateToLocalStreamUri(url, *uri_resolver);
}

Rect client_rect_to_bounds_rect(_In_ HWND hwnd)
{
    RECT client_rect = { 0 };
    WINRT_VERIFY(GetClientRect(hwnd, &client_rect));

    Rect bounds = {
        0,
        0,
        static_cast<float>(client_rect.right - client_rect.left),
        static_cast<float>(client_rect.bottom - client_rect.top)
    };

    return bounds;
}

void resize_web_view()
{
    Rect bounds = client_rect_to_bounds_rect(g_main_wnd);
    IWebViewControlSite webViewControlSite = (IWebViewControlSite)g_webview;
    webViewControlSite.Bounds(bounds);
}

#define SEND_TO_WEBVIEW_MSG 1

void send_message_to_webview(const std::wstring& msg)
{
    if (g_main_wnd != nullptr && wm_data_for_webview != 0)
    {
        // Allocate the COPYDATASTRUCT and message to pass to the Webview.
        // This is needed in order to use PostMessage, since COM calls to
        // g_webview.InvokeScriptAsync can't be made from other threads.

        PCOPYDATASTRUCT message = new COPYDATASTRUCT();
        DWORD buff_size = (DWORD)(msg.length() + 1);

        // 'wnd_static_proc()' will free the buffer allocated here.
        wchar_t* buffer = new wchar_t[buff_size];

        wcscpy_s(buffer, buff_size, msg.c_str());
        message->dwData = SEND_TO_WEBVIEW_MSG;
        message->cbData = buff_size * sizeof(wchar_t);
        message->lpData = (PVOID)buffer;
        WINRT_VERIFY(PostMessage(g_main_wnd, wm_data_for_webview, (WPARAM)g_main_wnd, (LPARAM)message));
    }
}

void send_message_to_powertoys_runner(const std::wstring& msg)
{
    if (g_message_pipe != nullptr)
    {
        g_message_pipe->send(msg);
    }
    else
    {
        // For Debug purposes, in case the webview is being run alone.
#ifdef _DEBUG
        MessageBox(g_main_wnd, msg.c_str(), L"From Webview", MB_OK);
        //throw in some sample data
        std::wstring debug_settings_info(LR"json({
            "general": {
              "startup": true,
              "enabled": {
                "Shortcut Guide":false,
                "Example PowerToy":true
              }
            },
            "powertoys": {
              "Shortcut Guide": {
                "version": "1.0",
                "name": "Shortcut Guide",
                "description": "Shows a help overlay with Windows shortcuts when the Windows key is pressed.",
                "icon_key": "pt-shortcut-guide",
                "properties": {
                  "press time" : {
                    "display_name": "How long to press the Windows key before showing the Shortcut Guide (ms)",
                    "editor_type": "int_spinner",
                    "value": 300
                  }
                }
              },
              "Example PowerToy": {
                "version": "1.0",
                "name": "Example PowerToy",
                "description": "Shows the different controls for the settings.",
                "overview_link": "https://github.com/microsoft/PowerToys",
                "video_link": "https://www.youtube.com/watch?v=d3LHo2yXKoY&t=21462",
                "properties": {
                  "test bool_toggle": {
                    "display_name": "This is what a bool_toggle looks like",
                    "editor_type": "bool_toggle",
                    "value": false
                  },
                  "test int_spinner": {
                    "display_name": "This is what a int_spinner looks like",
                    "editor_type": "int_spinner",
                    "value": 10
                  },
                  "test string_text": {
                    "display_name": "This is what a string_text looks like",
                    "editor_type": "string_text",
                    "value": "A sample string value"
                  },
                  "test color_picker": {
                    "display_name": "This is what a color_picker looks like",
                    "editor_type": "color_picker",
                    "value": "#0450fd"
                  },
                  "test custom_action": {
                    "display_name": "This is what a custom_action looks like",
                    "editor_type": "custom_action",
                    "value": "This is to be custom data. It\ncan\nhave\nmany\nlines\nthat\nshould\nmake\nthe\nfield\nbigger.",
                    "button_text": "Call a Custom Action!"
                  }
                }
              }
            }
          })json");
        send_message_to_webview(debug_settings_info);
#endif
    }
}

void receive_message_from_webview(const std::wstring& msg)
{
    if (msg[0] == '{')
    {
        // It's a JSON string, send the message to the PowerToys runner.
        std::thread(send_message_to_powertoys_runner, msg).detach();
    }
    else
    {
        // It's not a JSON string, check for expected control messages.
        if (msg == L"exit")
        {
            // WebView confirms the settings application can exit.
            WINRT_VERIFY(PostMessage(g_main_wnd, wm_destroy_window, 0, 0));
        }
        else if (msg == L"cancel-exit")
        {
            // WebView canceled the exit request.
            g_waiting_for_close_confirmation = false;
        }
    }
}

void initialize_webview(int nShowCmd)
{
    try
    {
        g_webview_process = WebViewControlProcess();
        auto asyncwebview = g_webview_process.CreateWebViewControlAsync((int64_t)g_main_wnd, client_rect_to_bounds_rect(g_main_wnd));
        asyncwebview.Completed([=](IAsyncOperation<WebViewControl> const& sender, AsyncStatus status) {
            if (status == AsyncStatus::Completed)
            {
                WINRT_VERIFY(sender != nullptr);
                g_webview = sender.GetResults();
                WINRT_VERIFY(g_webview != nullptr);

                // In order to receive window.external.notify() calls in ScriptNotify
                g_webview.Settings().IsScriptNotifyAllowed(true);

                g_webview.Settings().IsJavaScriptEnabled(true);

                g_webview.NewWindowRequested([=](IWebViewControl sender_requester, WebViewControlNewWindowRequestedEventArgs args) {
                    // Open the requested link in the default browser registered in the Shell
                    using winrt::Windows::Foundation::Uri;
                    Uri uri = args.Uri();
                    // WebView doesn't let us to open ms-settings:protocol links directly, so we translate it
                    // from a https placeholder
                    if (uri.AbsoluteUri() == L"https://ms_settings_startupapps/")
                        uri = Uri{ L"ms-settings:startupapps" };
                    winrt::Windows::System::Launcher::LaunchUriAsync(uri);
                });

                g_webview.ContentLoading([=](IWebViewControl sender, WebViewControlContentLoadingEventArgs const& args) {
                    ShowWindow(g_main_wnd, nShowCmd);
                });
                g_webview.ScriptNotify([=](IWebViewControl sender_script_notify, WebViewControlScriptNotifyEventArgs const& args_script_notify) {
                    // content called window.external.notify()
                    std::wstring message_sent = args_script_notify.Value().c_str();
                    receive_message_from_webview(message_sent);
                });
                g_webview.AcceleratorKeyPressed([&](IWebViewControl sender, WebViewControlAcceleratorKeyPressedEventArgs const& args) {
                    if (args.VirtualKey() == winrt::Windows::System::VirtualKey::F4)
                    {
                        // WebView swallows key-events. Detect Alt-F4 one and close the window manually.
                        const auto _ = g_webview.InvokeScriptAsync(hstring(L"exit_settings_app"), {});
                    }
                });
                resize_web_view();
#if defined(_DEBUG) && _DEBUG_WITH_LOCALHOST
                // Navigates to localhost:8080
                NavigateToLocalhostReactServer();
#else
                // Navigates to settings-html/index.html or index-dark.html
                NavigateToUri(g_start_in_dark_mode ? L"index-dark.html" : L"index.html");
#endif
            }
            else if (status == AsyncStatus::Error)
            {
                MessageBox(NULL, L"Failed to create the WebView control.\nPlease report the bug to https://github.com/microsoft/PowerToys/issues", L"PowerToys Settings Error", MB_OK);
                Trace::SettingsInitError(Trace::SettingsInitErrorCause::WebViewInitAsyncError);
                exit(1);
            }
            else if (status == AsyncStatus::Started)
            {
                // Ignore.
            }
            else if (status == AsyncStatus::Canceled)
            {
                // Ignore.
            }
        });
    }
    catch (hresult_error const& e)
    {
        Trace::SettingsInitError(Trace::SettingsInitErrorCause::WebViewInitWinRTException);
        WCHAR message[1024] = L"";
        StringCchPrintf(message, ARRAYSIZE(message), L"failed: %ls", e.message().c_str());
        MessageBox(g_main_wnd, message, L"Error", MB_OK);
    }
}

LRESULT CALLBACK wnd_proc_static(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_CLOSE:
        if (g_waiting_for_close_confirmation)
        {
            // If another WM_CLOSE is received while waiting for webview confirmation,
            // allow DefWindowProc to be called and destroy the window.
            break;
        }
        else
        {
            // Allow user to confirm exit in the WebView in case there's possible data loss.
            g_waiting_for_close_confirmation = true;
            if (g_webview != nullptr)
            {
                const auto _ = g_webview.InvokeScriptAsync(hstring(L"exit_settings_app"), {});
            }
            else
            {
                break;
            }
            return 0;
        }
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    case WM_SIZE:
        if (g_webview != nullptr)
        {
            resize_web_view();
        }
        break;
    case WM_CREATE:
        wm_data_for_webview = RegisterWindowMessageW(L"PTSettingsCopyDataWebView");
        wm_destroy_window = RegisterWindowMessageW(L"PTSettingsParentTerminated");
        break;
    case WM_DPICHANGED:
    {
        // Resize the window using the suggested rect
        RECT* const prcNewWindow = (RECT*)lParam;
        SetWindowPos(hWnd,
                     nullptr,
                     prcNewWindow->left,
                     prcNewWindow->top,
                     prcNewWindow->right - prcNewWindow->left,
                     prcNewWindow->bottom - prcNewWindow->top,
                     SWP_NOZORDER | SWP_NOACTIVATE);
    }
    break;
    case WM_NCCREATE:
    {
        // Enable auto-resizing the title bar
        EnableNonClientDpiScaling(hWnd);
    }
    break;
    default:
        if (message == wm_data_for_webview)
        {
            PCOPYDATASTRUCT msg = (PCOPYDATASTRUCT)lParam;
            if (msg->dwData == SEND_TO_WEBVIEW_MSG)
            {
                wchar_t* json_message = (wchar_t*)(msg->lpData);
                if (g_webview != nullptr)
                {
                    const auto _ = g_webview.InvokeScriptAsync(hstring(L"receive_from_settings_app"), { hstring(json_message) });
                }
                delete[] json_message;
            }
            // wnd_proc_static is responsible for freeing memory.
            delete msg;
        }
        else
        {
            if (message == wm_destroy_window)
            {
                DestroyWindow(hWnd);
            }
        }
        break;
    }
    return DefWindowProc(hWnd, message, wParam, lParam);
    ;
}

void register_classes(HINSTANCE hInstance)
{
    WNDCLASSEXW wcex;
    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style = 0;
    wcex.lpfnWndProc = wnd_proc_static;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = hInstance;
    wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(APPICON));
    wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground = g_start_in_dark_mode ? CreateSolidBrush(0) : (HBRUSH)(COLOR_WINDOW + 1);
    wcex.lpszMenuName = nullptr;
    wcex.lpszClassName = L"PTSettingsClass";
    wcex.hIconSm = nullptr;

    WINRT_VERIFY(RegisterClassExW(&wcex));
}

HWND create_main_window(HINSTANCE hInstance)
{
    RECT desktopRect;
    const HWND hDesktop = GetDesktopWindow();
    WINRT_VERIFY(hDesktop != nullptr);
    WINRT_VERIFY(GetWindowRect(hDesktop, &desktopRect));

    int wind_width = 1024;
    int wind_height = 700;
    DPIAware::Convert(nullptr, wind_width, wind_height);

    return CreateWindowW(
        L"PTSettingsClass",
        L"PowerToys Settings",
        WS_OVERLAPPEDWINDOW,
        (desktopRect.right - wind_width) / 2,
        (desktopRect.bottom - wind_height) / 2,
        wind_width,
        wind_height,
        nullptr,
        nullptr,
        hInstance,
        nullptr);
}

void wait_on_parent_process_thread(DWORD pid)
{
    HANDLE process = OpenProcess(SYNCHRONIZE, FALSE, pid);
    if (process != nullptr)
    {
        if (WaitForSingleObject(process, INFINITE) == WAIT_OBJECT_0)
        {
            // If it's possible to detect when the PowerToys process terminates, message the main window.
            CloseHandle(process);
            if (g_main_wnd)
            {
                WINRT_VERIFY(PostMessage(g_main_wnd, wm_destroy_window, 0, 0));
            }
        }
        else
        {
            CloseHandle(process);
        }
    }
}

void quit_when_parent_terminates(std::wstring parent_pid)
{
    DWORD pid = std::stol(parent_pid);
    std::thread(wait_on_parent_process_thread, pid).detach();
}

// Parse arguments: initialize two-way IPC message pipe and if settings window is to be started
// in dark mode.
void parse_args()
{
    // Expected calling arguments:
    // [0] - This executable's path.
    // [1] - PowerToys pipe server.
    // [2] - Settings pipe server.
    // [3] - PowerToys process pid.
    // [4] - optional "dark" parameter if the settings window is to be started in dark mode
    LPWSTR* argument_list;
    int n_args;

    argument_list = CommandLineToArgvW(GetCommandLineW(), &n_args);
    if (n_args > 3)
    {
        g_message_pipe = new TwoWayPipeMessageIPC(std::wstring(argument_list[2]), std::wstring(argument_list[1]), send_message_to_webview);
        g_message_pipe->start(nullptr);
        quit_when_parent_terminates(std::wstring(argument_list[3]));
    }
    else
    {
#ifndef _DEBUG
        MessageBox(nullptr, L"This executable isn't supposed to be called as a stand-alone process", L"Error running settings", MB_OK);
        exit(1);
#endif
    }
    if (n_args > 4)
    {
        g_start_in_dark_mode = wcscmp(argument_list[4], L"dark") == 0;
    }
    LocalFree(argument_list);
}

bool initialize_com_security_policy_for_webview()
{
    const wchar_t* security_descriptor =
        L"O:BA" // Owner: Builtin (local) administrator
        L"G:BA" // Group: Builtin (local) administrator
        L"D:"
        L"(A;;0x7;;;PS)" // Access allowed on COM_RIGHTS_EXECUTE, _LOCAL, & _REMOTE for Personal self
        L"(A;;0x3;;;SY)" // Access allowed on COM_RIGHTS_EXECUTE, & _LOCAL for Local system
        L"(A;;0x7;;;BA)" // Access allowed on COM_RIGHTS_EXECUTE, _LOCAL, & _REMOTE for Builtin (local) administrator
        L"(A;;0x3;;;S-1-15-3-1310292540-1029022339-4008023048-2190398717-53961996-4257829345-603366646)" // Access allowed on COM_RIGHTS_EXECUTE, & _LOCAL for Win32WebViewHost package capability
        L"S:"
        L"(ML;;NX;;;LW)"; // Integrity label on No execute up for Low mandatory level
    PSECURITY_DESCRIPTOR self_relative_sd{};
    if (!ConvertStringSecurityDescriptorToSecurityDescriptorW(security_descriptor, SDDL_REVISION_1, &self_relative_sd, nullptr))
    {
        return false;
    }

    on_scope_exit free_relative_sd([&] {
        LocalFree(self_relative_sd);
    });

    DWORD absolute_sd_size = 0;
    DWORD dacl_size = 0;
    DWORD group_size = 0;
    DWORD owner_size = 0;
    DWORD sacl_size = 0;

    if (!MakeAbsoluteSD(self_relative_sd, nullptr, &absolute_sd_size, nullptr, &dacl_size, nullptr, &sacl_size, nullptr, &owner_size, nullptr, &group_size))
    {
        if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
        {
            return false;
        }
    }

    typed_storage<SECURITY_DESCRIPTOR> absolute_sd{ absolute_sd_size };
    typed_storage<ACL> dacl{ dacl_size };
    typed_storage<ACL> sacl{ sacl_size };
    typed_storage<SID> owner{ owner_size };
    typed_storage<SID> group{ group_size };

    if (!MakeAbsoluteSD(self_relative_sd,
                        absolute_sd,
                        &absolute_sd_size,
                        dacl,
                        &dacl_size,
                        sacl,
                        &sacl_size,
                        owner,
                        &owner_size,
                        group,
                        &group_size))
    {
        return false;
    }

    return !FAILED(CoInitializeSecurity(
        absolute_sd,
        -1,
        nullptr,
        nullptr,
        RPC_C_AUTHN_LEVEL_PKT_PRIVACY,
        RPC_C_IMP_LEVEL_IDENTIFY,
        nullptr,
        EOAC_DYNAMIC_CLOAKING | EOAC_DISABLE_AAA,
        nullptr));
}

int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int nShowCmd)
{
    Trace::RegisterProvider();
    CoInitialize(nullptr);

    const bool should_try_drop_privileges = !initialize_com_security_policy_for_webview() && is_process_elevated(false);

    if (should_try_drop_privileges)
    {
        if (!drop_elevated_privileges())
        {
            MessageBox(NULL, L"Failed to drop admin privileges.\nPlease report the bug to https://github.com/microsoft/PowerToys/issues", L"PowerToys Settings Error", MB_OK);
            Trace::SettingsInitError(Trace::SettingsInitErrorCause::FailedToDropPrivileges);
            exit(1);
        }
    }

    g_hinst = hInstance;
    parse_args();
    register_classes(hInstance);
    g_main_wnd = create_main_window(hInstance);
    if (g_main_wnd == nullptr)
    {
        MessageBox(NULL, L"Failed to create main window.\nPlease report the bug to https://github.com/microsoft/PowerToys/issues", L"PowerToys Settings Error", MB_OK);
        exit(1);
    }
    initialize_webview(nShowCmd);

    // Main message loop.
    MSG msg;
    while (GetMessage(&msg, nullptr, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    Trace::UnregisterProvider();
    return (int)msg.wParam;
}