Compatibility: detect IL2CPP beside a selected nested executable (#540)

The automatic “Pause threads fully” setting detects Unity IL2CPP by looking for GameAssembly.dll beside the entry’s path. A Steam entry points at its install folder, so a direct launch of `bin/game.exe` misses `bin/GameAssembly.dll` and can leave real suspension disabled.

Author: alantangok

app/Madeira/LibraryBCD.swift

@@ -114,13 +114,21 @@ enum BCDLaunch {
         return nil
     }
 
-    /// A Unity IL2CPP build keeps GameAssembly.dll next to its exe. A Steam entry's
-    /// path is its install folder; another entry's is the exe.
+    /// A Unity IL2CPP build keeps GameAssembly.dll next to its exe. A direct Steam
+    /// launch can select an exe below its install folder; Dock keeps the root check.
     static func isUnityIL2CPP(_ entry: LibraryEntry) -> Bool {
         guard let url = LibraryEntry.hostURL(ofWindowsPath: entry.windowsPath) else { return false }
         var isDir: ObjCBool = false
         let fm = FileManager.default
         let folder = fm.fileExists(atPath: url.path, isDirectory: &isDir) && isDir.boolValue ? url : url.deletingLastPathComponent()
+        if let launched = LibraryEntry.hostURL(ofWindowsPath: entry.launchWindowsPath) {
+            let program = launched.resolvingSymlinksInPath().standardizedFileURL
+            let root = folder.resolvingSymlinksInPath().standardizedFileURL
+            if program.path.hasPrefix(root.path + "/"),
+               fm.fileExists(atPath: program.deletingLastPathComponent().appendingPathComponent("GameAssembly.dll").path) {
+                return true
+            }
+        }
         return fm.fileExists(atPath: folder.appendingPathComponent("GameAssembly.dll").path)
     }
 }

tests/host/check-il2cpp-detection.py

@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-3.0-or-later
+# Madeira Converter Exception: see LICENSE-EXCEPTION.md
+"""Compile the production IL2CPP detector and launch-path mapping on temporary games."""
+from pathlib import Path
+import subprocess
+import tempfile
+
+root = Path(__file__).resolve().parents[2]
+bcd = (root / 'app/Madeira/LibraryBCD.swift').read_text()
+library = (root / 'app/Madeira/Library.swift').read_text()
+
+
+def block(source, header):
+    start = source.index(header)
+    opening = source.index('{', start)
+    depth, end = 1, opening + 1
+    while depth:
+        depth += (source[end] == '{') - (source[end] == '}')
+        end += 1
+    return source[start:end]
+
+
+swift = '''import Foundation
+struct LibraryEntry {
+    var relativePath: String
+    var steamAppID: Int? = nil
+    var steamStart: String? = nil
+    var steamProgram: String? = nil
+    var epicAppName: String? = nil
+    var epicAntiCheatOff: Bool? = nil
+    static let epicAntiCheatOffProgram: [String: String] = [:]
+    static let hostDrive = URL(fileURLWithPath: CommandLine.arguments[1], isDirectory: true)
+'''
+for header in ['    var windowsPath:', '    var startsSteamGameDirectly:',
+               '    var launchRelativePath:', '    var launchWindowsPath:',
+               '    static func hostURL(ofWindowsPath']:
+    swift += block(library, header) + '\n'
+swift += '}\nenum BCDLaunch {\n' + block(bcd, '    static func isUnityIL2CPP(') + '\n}\n'
+swift += r'''
+let fm = FileManager.default
+let drive = LibraryEntry.hostDrive
+func create(_ path: String) throws {
+    let file = drive.appendingPathComponent(path)
+    try fm.createDirectory(at: file.deletingLastPathComponent(), withIntermediateDirectories: true)
+    try Data().write(to: file)
+}
+for path in ["Nested/bin/game.exe", "Nested/bin/GameAssembly.dll", "Root/game.exe",
+             "Root/GameAssembly.dll", "Plain/game.exe", "Other/game.exe", "Other/GameAssembly.dll"] {
+    try create(path)
+}
+try fm.createSymbolicLink(at: drive.appendingPathComponent("Plain/escape"),
+                         withDestinationURL: drive.appendingPathComponent("Other"))
+var failed = 0
+func expect(_ value: Bool, _ label: String) {
+    print((value ? "PASS: " : "FAIL: ") + label)
+    if !value { failed += 1 }
+}
+let directSteam = LibraryEntry(relativePath: "Nested", steamAppID: 1, steamStart: "game", steamProgram: "bin/game.exe")
+expect(BCDLaunch.isUnityIL2CPP(directSteam), "known nested Steam executable is detected")
+expect(BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Nested/bin/game.exe")), "local nested executable is detected")
+expect(BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Root", steamAppID: 2)), "root-level Steam DLL is still detected")
+expect(BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Root/game.exe")), "local root-level DLL is still detected")
+expect(!BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Plain/game.exe")), "non-IL2CPP game is not detected")
+expect(!BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Plain", steamAppID: 3, steamStart: "game", steamProgram: "../Other/game.exe")), "parent traversal cannot select another game's assembly")
+expect(!BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Plain", steamAppID: 3, steamStart: "game", steamProgram: "escape/game.exe")), "launch symlink cannot select another game's assembly")
+expect(!BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "../Other/game.exe")), "invalid entry path is rejected")
+expect(!BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Nested", steamAppID: 1)), "unknown Dock program does not scan arbitrary subdirectories")
+expect(!BCDLaunch.isUnityIL2CPP(LibraryEntry(relativePath: "Nested", steamAppID: 1, steamProgram: "bin/game.exe")), "a dormant direct-start choice does not change a Dock launch")
+exit(failed == 0 ? 0 : 1)
+'''
+with tempfile.TemporaryDirectory(prefix='madeira-il2cpp-detection-') as tmp:
+    directory = Path(tmp)
+    program = directory / 'detect.swift'
+    program.write_text(swift)
+    subprocess.run(['swift', str(program), str(directory / 'drive_c')], check=True)
+print('check-il2cpp-detection: PASS')

tests/host/check-real-suspend-game.py

@@ -65,6 +65,7 @@ def block(source, header):
 defer { defaults.removePersistentDomain(forName: suite) }
 struct LibraryEntry {
     var windowsPath: String
+    var launchWindowsPath: String { windowsPath }
     var desktop: Bool? = nil
     static func hostURL(ofWindowsPath path: String) -> URL? { URL(fileURLWithPath: path) }
 }