feat: allow injecting into all extensions

Feather/Backend/Observable/OptionsManager.swift

@@ -100,7 +100,9 @@ struct Options: Codable, Equatable {
 	var removeProvisioning: Bool
 	/// Forcefully rename string files for App name
 	var changeLanguageFilesForCustomDisplayName: Bool
-
+	/// If tweaks should be injected into all app extensions (PlugIns and Extensions)
+	var injectIntoExtensions: Bool
+
 	// MARK: Experiments
 
 	/// Modifies app to support liquid glass
@@ -143,6 +145,7 @@ struct Options: Codable, Equatable {
 		removeURLScheme: false,
 		removeProvisioning: false,
 		changeLanguageFilesForCustomDisplayName: false,
+		injectIntoExtensions: false,
 
 		// MARK: Experiments
 

Feather/Resources/Localizable.xcstrings

@@ -6893,6 +6893,17 @@
         }
       }
     },
+    "Inject into Extensions" : {
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Inject into Extensions"
+          }
+        }
+      }
+    },
     "Injection Folder" : {
       "extractionState" : "manual",
       "localizations" : {

Feather/Utilities/Handlers/TweakHandler.swift

@@ -14,6 +14,7 @@ class TweakHandler {
 	private let _fileManager = FileManager.default
 	private var _urlsToInject: [URL] = []
 	private var _directoriesToCheck: [URL] = []
+	private var _injectedDylibNames: [String] = []
 
 	private let _app: URL
 	private var _options: Options
@@ -94,6 +95,11 @@ class TweakHandler {
 				try await _handleExtractedDirectoryContents(at: _urlsToInject)
 			}
 		}
+
+		// inject into all extensions if enabled
+		if !_injectedDylibNames.isEmpty {
+			_injectIntoAllExtensions(dylibNames: _injectedDylibNames)
+		}
 	}
 
 	// finally, handle extracted contents
@@ -157,6 +163,8 @@ class TweakHandler {
 			appExecutable: appexe.path,
 			with: "\(_options.injectPath.rawValue)\(injectFolder.rawValue)\(destinationURL.lastPathComponent)"
 		)
+
+		_injectedDylibNames.append(destinationURL.lastPathComponent)
 	}
 
 	// Inject imported framework dir
@@ -249,6 +257,92 @@ class TweakHandler {
 			}
 		}
 	}
+
+	// Discovers all .appex bundles in the app's PlugIns and Extensions directories
+	private func _discoverAppExtensions() -> [URL] {
+		var extensions: [URL] = []
+
+		let plugInsPath = _app.appendingPathComponent("PlugIns")
+		let extensionsPath = _app.appendingPathComponent("Extensions")
+
+		for directory in [plugInsPath, extensionsPath] {
+			guard _fileManager.fileExists(atPath: directory.path) else { continue }
+
+			do {
+				let contents = try _fileManager.contentsOfDirectory(
+					at: directory,
+					includingPropertiesForKeys: nil,
+					options: [.skipsHiddenFiles]
+				)
+
+				let appexBundles = contents.filter { url in
+					url.pathExtension.lowercased() == "appex" && url.hasDirectoryPath
+				}
+
+				extensions.append(contentsOf: appexBundles)
+			} catch {
+				Logger.misc.warning("Failed to enumerate \(directory.path): \(error.localizedDescription)")
+			}
+		}
+
+		return extensions
+	}
+
+	// Injects a dylib into an extension's executable
+	private func _injectIntoExtension(extensionURL: URL, dylibName: String) {
+		guard let extensionBundle = Bundle(url: extensionURL),
+				let extensionExecutable = extensionBundle.executableURL else {
+			Logger.misc.warning("Skipping \(extensionURL.lastPathComponent): couldn't read bundle")
+			return
+		}
+
+		var injectFolder = _options.injectFolder
+		if _options.injectPath == .rpath && _options.injectFolder == .frameworks {
+			injectFolder = .root
+		}
+
+		let injectPath: String
+		if _options.injectPath == .rpath {
+			injectPath = "@rpath/\(dylibName)"
+		} else {
+			if injectFolder == .frameworks {
+				injectPath = "@executable_path/../../Frameworks/\(dylibName)"
+			} else {
+				injectPath = "@executable_path/../../\(dylibName)"
+			}
+		}
+
+		let success = Zsign.injectDyLib(
+			appExecutable: extensionExecutable.path,
+			with: injectPath
+		)
+
+		if success {
+			Logger.misc.info("Injected \(dylibName) into extension: \(extensionURL.lastPathComponent)")
+		} else {
+			Logger.misc.warning("Failed to inject into extension: \(extensionURL.lastPathComponent)")
+		}
+	}
+
+	// Injects all dylibs into all discovered extensions
+	private func _injectIntoAllExtensions(dylibNames: [String]) {
+		guard _options.injectIntoExtensions else { return }
+
+		let extensions = _discoverAppExtensions()
+
+		guard !extensions.isEmpty else {
+			Logger.misc.info("No app extensions found for injection")
+			return
+		}
+
+		Logger.misc.info("Found \(extensions.count) app extension(s) for injection")
+
+		for extensionURL in extensions {
+			for dylibName in dylibNames {
+				_injectIntoExtension(extensionURL: extensionURL, dylibName: dylibName)
+			}
+		}
+	}
 }
 
 // MARK: - Find correct files in debs

Feather/Views/Signing/SigningTweaksView.swift

@@ -30,6 +30,10 @@ struct SigningTweaksView: View {
 					selection: $options.injectFolder,
 					values: Options.InjectFolder.allCases
 				)
+
+				Toggle(isOn: $options.injectIntoExtensions) {
+					Label(.localized("Inject into Extensions"), systemImage: "syringe")
+				}
 			}
 
 			NBSection(.localized("Tweaks")) {