XPC is the preferred inter-process communication (IPC) mechanism on Apple platforms. XPC has three APIs: The high-level NSXPCConnection API, for Objective-C and Swift The low-level Swift API, introduced with macOS 14 The low-level C API, which, while callable from all languages, works best with C-based languages General: DevForums tag: XPC Creating XPC services documentation NSXPCConnection class documentation Low-level API documentation XPC has extensive man pages — For the low-level API, start with the xpc man page; this is the original source for the XPC C API documentation and still contains titbits that you can’t find elsewhere. Also read the xpcservice.plist man page, which documents the property list format used by XPC services. Daemons and Services Programming Guide archived documentation WWDC 2012 Session 241 Cocoa Interprocess Communication with XPC — This is no longer available from the Apple Developer website )-: Technote 2083 Daemons and Agents — It hasn’t been updated in… well… decades, but it’s still remarkably relevant. TN3113 Testing and Debugging XPC Code With an Anonymous Listener XPC and App-to-App Communication DevForums post Validating Signature Of XPC Process DevForums post Related tags include: Inter-process communication, for other IPC mechanisms Service Management, for installing and uninstalling Service Management login items, launchd agents, and launchd daemons Share and Enjoy — Quinn “The Eskimo!” @ Developer Technical Support @ Apple let myEmail = "eskimo" + "1" + "@" + "apple.com"

I create a protocol that had, among other things: @objc func setList(_: [MyType], withReply: @escaping (Error?) -> Void) The daemon part is in Swift, while the calling part is in Objective-C. Because why not? (Actually, because the calling part has to deal with C++ code, so that's ObjC++; however, I wanted the stronger typing and runtime checking for the daemon part, so I wrote it in Swift.) The ObjC part uses NSArray<MyType*>. I set up an NSXPCConnection link, and create a (synchronous) proxy with the right protocol name. But when I try to do the XPC setList call, I get an error. I assume that's because it doesn't like the signature. (Surely this is logged somewhere? I couldn't find it, if so. 😩) But... if I have a signature of @objc func addItem(_: MyType, withReply: @escaping (Error?) -> Void), then it works. So I assume it's the array. (Oh, I've also tried it without the @objc; the protocol itself is defined as @objc.) I've tried changing to protocol signature to using NSArray, but same thing.

Hi :wave: I started a new project to experiment with EndpointSecurity framework. It seems to have been worked, but when I try to add XPC I face some troubles. I am not able to send XPC message from my app to my system extension. No runtime error, but when I'm inspecting logs: That correspond to this code: https://github.com/tony-go/TestES/blob/main/Extension/main.swift#L21-L30 Full project: https://github.com/tony-go/TestES/ I thought at first that it could come from a missing @objc somehere but it does not seems ... I also wonder why I cannot catch this error at runtime ?

hi all. I subscribe the notify write event, every time I recieve a notify write event message i will send log data and reply block(didn't do nothing) with async method to host app(Objc XPC API).host app will reply immediately once it recieves data. after a while my sysext crashed, then I checked system log find the log below. launchd: exited with exit reason (namespace: 30 code: 0xc40000000004aaaa) - (unknown reason) is it because of exceeding the maximum limit of xpc's block queue length, or too many memory allocation, or... by the way, host app didn't crash. how this happened exactly? how could i solve it?

I'm using XPC to do IPC with an agent service. I use NSXPCConnection initWithMachServiceName to create the connection and active it. Then I get the agent service remote object proxy with method remoteObjectProxyWithErrorHandler. But when the agent service unloaded, I can also get the remote proxy without any error. Is there anyway to check XPCConnection really connect to a XPC server?

Hi everyone, first-time caller, long-ti... wait, no, I just got here. :) I am relatively new to all things Apple, so apologies in advance if it takes me a few goes to properly explain things. We have a framework, which includes an API, an XPC service, etc, and we have a device driver. We also have some sample apps that use the framework, and if they have the app sandbox capability, then we expect them to use the XPC Service instead of accessing our driver directly. This works fine on Monterey and presumably has worked fine on all previous versions of MacOS. Something seems to have changed on Ventura, and we don't understand what. When we build the same app on Ventura, it appears to be in the sandbox (according to the Sandbox column in Activity Monitor), but in the Console there is this line (twice): default <time> <OurAppName> Revoking sandbox extension; key = 0 Which we suspect is linked to the fact that the app then does not use the XPC Service, and instead accesses the driver directly, much to our surprise. Software built on developer's machines is "Automatically managed" and "Signed to Run Locally" in case that matters. Do we need to change our code to support Ventura and onward? Or is it a bizarre bug? Oh, I should say that I'm running the latest version of Ventura (13.6.7 as of writing) but not the latest Xcode (14.2 (14C18)) and CLI tools... can't remember how to find that version... Apple clang version 14.0.0 (clang-1400.0.29.202). Any help would be appreciated, thanks. Jeremy

I create a camera extension and App can push video data to camera extension with sinkStream. I want to monitor the number of clients connected to the camera extension and close the app's push stream when the number of connected client is zero.

I am attempting to install and utilize an agent using the new(ish) SMAppService API with an existing app. The agent appears to install (no error is returned), but when I try to start the agent from Terminal, I get the following in the launchd.log: 2024-04-22 09:57:27.469039 (gui/502/com.redacted.service.agent) : internal event: WILL_SPAWN, code = 0 2024-04-22 09:57:27.469080 (gui/502/com.redacted.service.agent) : service state: spawn scheduled 2024-04-22 09:57:27.469081 (gui/502/com.redacted.service.agent) : service state: spawning 2024-04-22 09:57:27.469100 (gui/502/com.redacted.service.agent) : launching: one-shot 2024-04-22 09:57:27.469105 (gui/502/com.redacted.service.agent) : Allowing non-reentrant proxy for resolving path 2024-04-22 09:57:27.469947 (gui/502/com.redacted.service.agent [71866]) : xpcproxy spawned with pid 71866 2024-04-22 09:57:27.469960 (gui/502/com.redacted.service.agent [71866]) : internal event: SPAWNED, code = 0 2024-04-22 09:57:27.469964 (gui/502/com.redacted.service.agent [71866]) : service state: xpcproxy 2024-04-22 09:57:27.469997 (gui/502/com.redacted.service.agent [71866]) : internal event: SOURCE_ATTACH, code = 0 2024-04-22 09:57:27.506283 (gui/502/com.redacted.service.agent [71866]) : Service could not initialize: posix_spawn(/Users/chrisf/Library/Developer/Xcode/DerivedData/Redacted-gttupgdyakodzddurpavhmscwabs/Build/Products/Debug/Redacted App.app/Contents/MacOS/Service Agent.app), error 0xd - Permission denied 2024-04-22 09:57:27.506306 (gui/502/com.redacted.service.agent [71866]) : initialization failure: 23E224: xpcproxy + 31420 [1098][A7EF179C-FBCC-349E-A7D2-09B2F1408413]: 0xd 2024-04-22 09:57:27.506309 (gui/502/com.redacted.service.agent [71866]) : internal event: INIT, code = 13 2024-04-22 09:57:27.506313 (gui/502/com.redacted.service.agent [71866]) : job state = spawn failed 2024-04-22 09:57:27.507148 (gui/502/com.redacted.service.agent [71866]) : xpcproxy exited due to exit(78) 2024-04-22 09:57:27.507153 (gui/502/com.redacted.service.agent [71866]) : exited due to exit(78) 2024-04-22 09:57:27.507162 (gui/502/com.redacted.service.agent [71866]) : already handled failed init, ignoring 2024-04-22 09:57:27.507170 (gui/502/com.redacted.service.agent [71866]) : service state: exited 2024-04-22 09:57:27.507186 (gui/502/com.redacted.service.agent [71866]) : internal event: EXITED, code = 0 (tldr: error 0xd - Permission denied) I'd also be curious how we are expected to launch agents once registered with SMAppService. Is it sufficient simply to make an XPC call to an exposed method? Thanks!

Hello Apple Developer Community, I'm encountering an issue with my macOS application where I'm receiving the following error message: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named com.FxPlugTestXPC was invalidated: failed at lookup with error 159 - Sandbox restriction." UserInfo={NSDebugDescription=The connection to service named com.FxPlugTestXPC was invalidated: failed at lookup with error 159 - Sandbox restriction.} This error occurs when my application tries to establish a connection to an XPC service named com.FxPlugTestXPC. It appears to be related to a sandbox restriction, but I'm unsure how to resolve it. I've checked the sandboxing entitlements and ensured that the necessary permissions are in place. However, the issue persists. Has anyone encountered a similar error before? If so, could you please provide guidance on how to troubleshoot and resolve this issue? Any help or insights would be greatly appreciated. Thank you. this is some photos about my entitlements :

I noticed a problem while writing a program using XPC on macOS. When I write it in the form of a closure that receives the result of an XPC call, I can't receive it forever. I add an XPC target in Xcode, the sample code is used in the pass closure format, but can't I use closure passing with XPC? My Environment: Xcode 15.3 macOS 14.4.1 caller (closure version) struct ContentView: View { @State var callbackResult: String = "Waiting…" var body: some View { Form { Section("Run XPC Call with no argument and no return value using callback") { Button("Run…") { callbackResult = "Running…" let service = NSXPCConnection(serviceName: "net.mtgto.example-nsxpc-throws-error.ExampleXpc") service.remoteObjectInterface = NSXPCInterface(with: ExampleXpcProtocol.self) service.activate() guard let proxy = service.remoteObjectProxy as? any ExampleXpcProtocol else { return } defer { service.invalidate() } proxy.performCallback { callbackResult = "Done" } } Text(callbackResult) ... } } } callee (closure version) @objc protocol ExampleXpcProtocol { func performCallback(with reply: @escaping () -> Void) } class ExampleXpc: NSObject, ExampleXpcProtocol { @objc func performCallback(with reply: @escaping () -> Void) { reply() } } I found this problem can be solved by receiving asynchronous using Swift Concurrency. caller (async version) struct ContentView: View { @State var callbackResult: String = "Waiting…" var body: some View { Form { Section("Run XPC Call with no argument and no return value using callback") { Button("Run…") { simpleAsyncResult = "Running…" Task { let service = NSXPCConnection(serviceName: "net.mtgto.example-nsxpc-throws-error.ExampleXpc") service.remoteObjectInterface = NSXPCInterface(with: ExampleXpcProtocol.self) service.activate() guard let proxy = service.remoteObjectProxy as? any ExampleXpcProtocol else { return } defer { service.invalidate() } await proxy.performNothingAsync() simpleAsyncResult = "DONE" } Text(simpleAsyncResult) ... } } } callee (async version) @objc protocol ExampleXpcProtocol { func performNothingAsync() async } class ExampleXpc: NSObject, ExampleXpcProtocol { @objc func performNothingAsync() async {} } To simplify matters, I write source code that omits the arguments and return value, but it is not also invoked by using callback style. All sample codes are available in https://github.com/mtgto/example-nsxpc-throws-error

Development Environment: Xcode Version: 14.3.1 macOS Ventura Version: 13.6.2 Architecture: Intel I am developing a macOS app with an accompanying XPC service and am encountering an issue where the XPC connection is immediately invalidated upon trying to establish it. The error message received is: Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named com.appname.macos.app-name-xpc was invalidated." UserInfo={NSDebugDescription=The connection to service named com.appname.macos.app-name-xpc was invalidated: failed at lookup with error 3 - No such process.} Here's what I have verified so far: The XPC service has the correct CFBundleIdentifier and is located within the Contents/XPCServices directory of my app's bundle. Info.plist for the XPC service has ServiceType set to Bundled. The XPC service target's Installation Directory is the default location for XPC services (@executable_path/../XPCServices). Code signing and entitlements have been verified for both the main app and the XPC service, and disabling the sandbox doesn't resolve the issue. The main app and XPC service are part of the same App Group, and both have the App Sandbox capability enabled. Here's a snippet of the Swift code that establishes the XPC connection: let xpcConnection = NSXPCConnection(serviceName: "com.appname.macos.app-name-xpc") xpcConnection.remoteObjectInterface = NSXPCInterface(with: ServiceProtocol.self) xpcConnection.resume() And here's the ServiceProtocol for reference: @objc public protocol ServiceProtocol: NSObjectProtocol { @objc func executeUnixExecutable(arguments: [String], completionHandler: @escaping (ResultType) -> Void) func interruptUnixExecutable() func closeUnixExecutablePipes() } When I run the app, the connection is invalidated without any further details as to why. I'm not sure if I'm missing a configuration step or if there's an issue with my XPC service setup. Has anyone experienced this issue or have suggestions on what else I can check to resolve this?

I've been experimenting with the new low-level Swift API for XPC (XPCSession and XPCListener). The ability to send and receive Codable messages is an appealing alternative to making an @objc protocol in order to use NSXPCConnection from Swift — I can easily create an enum type whose cases map onto the protocol's methods. But our current XPC code validates the incoming connection using techniques similar to those described in Quinn's "Apple Recommended" response to the "Validating Signature Of XPC Process" thread. I haven't been able to determine how to do this with XPCListener; neither the documentation nor the Swift interface have yielded any insight. The Creating XPC Services article suggests using Xcode's XPC Service template, which contains this code: let listener = try XPCListener(service: serviceName) { request in request.accept { message in performCalculation(with: message) } } The apparent intent is to inspect the incoming request and decide whether to accept it or reject it, but there aren't any properties on IncomingSessionRequest that would allow the service to make that decision. Ideally, there would be a way to evaluate a code signing requirement, or at least obtain the audit token of the requesting process. (I did notice that a function xpc_listener_set_peer_code_signing_requirement was added in macOS 14.4, but it takes an xpc_listener_t argument and I can't tell whether XPCListener is bridged to that type.) Am I missing something obvious, or is there a gap in the functionality of XPCListener and IncomingSessionRequest?

I have an application, it has main process and some child processes. As we want those child processes to have their own minimum sandbox privilege, not inheriting from parent process, we plan to use XPCService which uses a NSTask to launch those child processes, so those child processes can have its own sandbox privilege. We plan to deliver the application to Mac App Store, so process mode is: the sandboxed main process builds connections to the unsandboxed XPCService, the unsandboxed XPCService launch those sandboxed child processes. Can this process mode pass the Mac App Store rules? I see, there is a rule that all processes must be sandboxed, including XPCService. But I tested locally, the Application downloaded from Mac apple store also launches unsandboxed XPCService, like OneDrive. Do you have any suggestions for my application scenario, sandboxed child processes having its own privilege not inheriting from parent?

We are working on a command line daemon (started with launchd) for a UI to communicate with using XPC. The functions we have been using so far work correctly, but they only take arguments and return void. We wanted to add a function with a simple reply block to see if the daemon is running or not, and we may need to get data back in the future. But it is not working. For example, this is working: if let proxy = connectionToService.remoteObjectProxyWithErrorHandler({ error in print(error.localizedDescription) }) as? TheDaemonProtocol { proxy.doStuff("Test string") } But this returns an error "Couldn’t communicate with a helper application." if let proxy = connectionToService.remoteObjectProxyWithErrorHandler({ error in print(error.localizedDescription) }) as? TheDaemonProtocol { proxy.isUp { reply in print("reply: \(reply)") } } isUp() is coded to only return true for now. @objc func isUp(reply: @escaping (Bool) -> Void) { reply(true) } TIA for any help!

I'm working on a macOS application that deals with a few external dependencies that can only be compiled for intel (x86_64) but I want the app to run natively on both arm and x86_64. One idea I have been playing with is to move the x86_64 dependencies to an xpc service compiled only as x86_64 and use the service only the intel machine. However, I can't figure out how to setup my project to compile everything at once... Any ideas? Is this even possible? If not, I'm open to suggestions... Thanks

Quinn, you've often suggested that to validate the other side of an XPC connection, we should use the audit token. But that's not available from the XPC object, whereas the PID is. So everyone uses the PID. While looking for something completely unrelated, I found this in the SecCode.h file OSStatus SecCodeCreateWithXPCMessage(xpc_object_t message, SecCSFlags flags, SecCodeRef * __nonnull CF_RETURNS_RETAINED target); Would this be the preferred way to do this now? At least from 11.0 and up. Like I said, I was looking for something completely unrelated and found this and don't have the cycles right now to try it. But it looks promising from the description and I wanted to check in with you about it in case you can say yes or no before I get a chance to test it. Thanks

Hi! I'm looking for some insight and guidance on using the Foundation.Process type with a PTY (Psuedo Terminal) so that the subprocess can accept input and behave as if it was running via a terminal. The reason for needing a PTY is that for programs like ssh or in my case (xcodes) which ask for user input including passwords, running these via Foundation.Process does not display the prompts to the user as the output is usually buffered (this works fine in the Xcode debugger console but when running via a real terminal that is buffered the prompts are never displayed in the terminal) Looking at other threads it seems like correct approach here is create a PTY and use the filehandles to attach to the Process. While I've got this to work to the point where prompts are now shown, I cant seem to figure out how to pass input back to the process as these are being controlled by the PTY. Here is my Process setup: let process = Process() // Setup the process with path, args, etc... // Setup the PTY handles var parentDescriptor: Int32 = 0 var childDescriptor: Int32 = 0 guard Darwin.openpty(&parentDescriptor, &childDescriptor, nil, nil, nil) != -1 else {   fatalError("Failed to spawn PTY") } parentHandle = FileHandle(fileDescriptor: parentDescriptor, closeOnDealloc: true) childHandle = FileHandle(fileDescriptor: childDescriptor, closeOnDealloc: true) process.standardInput = childHandle process.standardOutput = childHandle process.standardError = childHandle With this setup I then read the parent handle and output any result it gets (such as the input prompts): parentHandle?.readabilityHandler = { handle in   guard let line = String(data: handle.availableData, encoding: .utf8), !line.isEmpty else {     return   }   logger.notice("\(line)") } When process.run() is executed the program runs and I can see it asks for Apple ID: input in my terminal, however, when typing input into the terminal the process does not seem to react to this input. I've tried forwarding the FileHandle.standardInput: FileHandle.standardInput.readabilityHandler = { handle in   parentHandle?.write(handle.availableData) } But this doesn't seem to work either. What is the recommended way to setup a PTY with Foundation.Process for executing arbitrary programs and having them behave as if they were being run in a terminal context? Most of the resources I found online are about other languages and I'd like to stick with Foundation.Process vs. doing anything custom in C/C++ if possible as it just makes it easier to reason about / maintain. The resources for Swift on this topic are very lacking and I've checked out some open source projects that claim to do this but most require manually sending input to the PTY handle vs. accepting them from the user in a terminal. Any insight / help is very much appreciated!

Hi there :) I try to put an Xcode project in place within a LaunchAgent. The ultimate goal is to have an "application" with two component: macOS application with just an basic UI all the logic happens in a LaunchAgent that runs on background and is launch at startup. The macOS app uses XPC to send messages to the agent that will run either the app is opened or not. I struggled at first having this error (for the agent): An XPC Service cannot be run directly. Then I found using MachServices key in the .plist of the agent fixes the issue, plus: let listener = NSXPCListener.init(machServiceName: "com.tonygo.NetworkMonitorAgent") Then I wonder: Do we have somewhere a documentation about how to setup a LaunchAgent in Xcode I create the plist of the agent on side and run it manually, I could do this in a more automatic way How could I package a macOS applciation that will contains the agent, install it and load the agent? Note: This is mainly for learning and understanding what we could do at each level (XPCService, LaunchAgents, LaunchDaemon, etc.).

Greetings! I've added a Matter accessory via the Apple Home app. In my app, I'm attempting to commission this device and add it to my fabric. However, when I try to open the commissioning window, I receive an error stating, MTRBaseDevice doesn't support openCommissioningWindowWithDiscriminator over XPC. It appears that opening a commissioning window via an XPC connection is not yet supported. Is there another method to commission the device? Can I retrieve the setup payload from the MTRBaseDevice object or the shared MTRDeviceController? Here's the simplified version of my code: var home: HMHome // HMHome received via HMHomeManager var accessory: HMAccessory = home.accessory[0] // my Matter-supported accessory let deviceController = MTRDeviceController.sharedController( withID: home.matterControllerID as NSCopying, xpcConnect: home.matterControllerXPCConnectBlock ) let device = MTRBaseDevice( nodeID: accessory.matterNodeID as NSNumber, controller: deviceController ) device.openCommissioningWindow( withDiscriminator: 0, duration: 900, queue: .main) { payload, error in if let payload { // payload not received } else if let error { // I'm getting here "Error Domain=MTRErrorDomain Code=6 "(null)"" // and "MTRBaseDevice doesn't support openCommissioningWindowWithDiscriminator over XPC" logged in the console print(error) }

I want to build an Xcode Source Code Editor extension that triggers an XPC service shows a gui that can handle user interactions Is it possible in any way ? what are the alternatives to display the UI and allow the user to interact on it ?