XPC is a a low-level (libSystem) interprocess communication mechanism that is based on serialized property lists.

Posts under XPC tag

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setCodeSigningRequirement seems not to work in new Service Management API setup.
I have developed a sample app following the example found Updating your app package installer to use the new Service Management API and referring this discussion on XPC Security. The app is working fine, I have used Swift NSXPCConnection in favour of xpc_connection_create_mach_service used in the example. (I am running app directly from Xcode) I am trying to set up security requirements for the client connection using setCodeSigningRequirement on the connection instance. But it fails for even basic requirement connection.setCodeSigningRequirement("anchor apple"). Error is as follows. cannot open file at line 46986 of [554764a6e7] os_unix.c:46986: (0) open(/private/var/db/DetachedSignatures) - Undefined error: 0 xpc_support_check_token: anchor apple error: Error Domain=NSOSStatusErrorDomain Code=-67050 "(null)" status: -67050 I have used codesign -d --verbose=4 /path/to/executable to check the attributes I do get them in the terminal. Other way round, I have tried XPC service provider sending back process id (pid) with each request, and I am probing this id to get attributes using this code which gives all the details. func inspectCodeSignature(ofPIDString pidString: String) { guard let pid = pid_t(pidString) else { print("Invalid PID string: \(pidString)") return } let attributes = [kSecGuestAttributePid: pid] as CFDictionary var codeRef: SecCode? let status = SecCodeCopyGuestWithAttributes(nil, attributes, [], &codeRef) guard status == errSecSuccess, let code = codeRef else { print("Failed to get SecCode for PID \(pid) (status: \(status))") return } var staticCode: SecStaticCode? let staticStatus = SecCodeCopyStaticCode(code, [], &staticCode) guard staticStatus == errSecSuccess, let staticCodeRef = staticCode else { print("Failed to get SecStaticCode (status: \(staticStatus))") return } var infoDict: CFDictionary? if SecCodeCopySigningInformation(staticCodeRef, SecCSFlags(rawValue: kSecCSSigningInformation), &infoDict) == errSecSuccess, let info = infoDict as? [String: Any] { print("🔍 Code Signing Info for PID \(pid):") print("• Identifier: \(info["identifier"] ?? "N/A")") print("• Team ID: \(info["teamid"] ?? "N/A")") if let entitlements = info["entitlements-dict"] as? [String: Any] { print("• Entitlements:") for (key, value) in entitlements { print(" - \(key): \(value)") } } } else { print("Failed to retrieve signing information.") } var requirement: SecRequirement? if SecRequirementCreateWithString("anchor apple" as CFString, [], &requirement) == errSecSuccess, let req = requirement { let result = SecStaticCodeCheckValidity(staticCodeRef, [], req) if result == errSecSuccess { print("Signature is trusted (anchor apple)") } else { print("Signature is NOT trusted by Apple (failed anchor check)") } } var infoDict1: CFDictionary? let signingStatus = SecCodeCopySigningInformation(staticCodeRef, SecCSFlags(rawValue: kSecCSSigningInformation), &infoDict1) guard signingStatus == errSecSuccess, let info = infoDict1 as? [String: Any] else { print("Failed to retrieve signing information.") return } print("🔍 Signing Info for PID \(pid):") for (key, value) in info.sorted(by: { $0.key < $1.key }) { print("• \(key): \(value)") } } If connection.setCodeSigningRequirement does not works I plan to use above logic as backup. Q: Please advise is there some setting required to be enabled or I have to sign code with some flags enabled. Note: My app is not running in a Sandbox or Hardened Runtime, which I want.
12
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378
Apr ’25
macOS 14 XPC vs Foundation XPC
I'm looking into a newer XPC API available starting with macOS 14. Although it's declared as a low-level API I can't figure it how to specify code signing requirement using XPCListener and XPCSession. How do I connect it with xpc_listener_set_peer_code_signing_requirement and xpc_connection_set_peer_code_signing_requirement which require xpc_listener_t and xpc_connection_t respectively? Foundation XPC is declared as a high-level API and provides easy ways to specify code signing requirements on both ends of xpc. I'm confused with all these XPC APIs and their future: Newer really high-level XPCListener and XPCSession API (in low-level framework???) Low-level xpc_listener_t & xpc_connection_t -like API. Is it being replaced by newer XPCListener and XPCSession? How is it related to High-level Foundation XPC? Are NSXPCListener and NSXPCConnection going to be deprecated and replaced by XPCListener and XPCSession??
2
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845
Aug ’25
Missing flows for content filter on macOS 15 Sequoia
We use as content filter in our app to monitor flows, we gather data about the flow and block flows deemed suspicious. Our content filter is activated/deactivated by a UI app but the flows are reported via XPC to a separate daemon process for analysis. As of macOS 15, we are seeing cases where flows are missing or flows are not received at all by the content filter. The behaviour is not consistent, some devices seem to receive flows normally but others don't. It appears Intel devices are much less prone to showing the problem, whereas Arm devices routinely exhibit missing flows. On macOS 14 or earlier, there is no sign of missing flows. Testing on earlier beta versions of macOS 15 did not appear to show the problem, however I can't rule out if issue was present but it wasn't spotted. Experimenting with simple examples of using a content filter (e.g. QNE2FilterMac) does not appear to reproduce the issue. Questions, What has changed between macOS 14 and 15 that could be the cause of the lack of flows? Is our approach to using an app activated content filter reporting to a daemon connected via XPC unsupported?
7
1
1.1k
Aug ’25
GUI + XPC Service App Architecture Performance
Let's image that someone wants to use a background service to keep track of FSEvents activity, at the file level (a firehose, some might say). I choose this example, to indicate the volume and rate of data transmission in question. I'm not creating a front-end for FSEvents data, but my background service may generate data at a similar pace. The service runs off of user defined document/s that specify the FSEvent background filtering to be applied. Those that match get stored into a database. But filters can match on almost all the data being emitted by FSEvents. The user decides to check on the service's activity and database writes by launching a GUI that sends requests to the background service using XPC. So the GUI can request historic data from a database, but also get a real-time view of what FS events the service is busy filtering. So it's a client-server approach, that's concerned with monitoring an event stream over XPC. I understand XPC is a request/response mechanism, and I might look into using a reverse connection here, but my main concern is one of performance. Is XPC capable of coping with such a high volume of data transmision? Could it cope with 1000s of rows of table data updates per second sent to a GUI frontend? I know there are streaming protocol options that involve a TCP connection, but I really want to stay away from opening sockets.
7
0
1.2k
Jan ’26
XPC Connection with Network Extension fails after upgrade
Hi Team, I have a Network Extension application and UI frontend for it. The UI frontend talks to the Network Extension using XPC, as provided by NEMachServiceName. On M2 machine, The application and XPC connection works fine on clean installation. But, when the application is upgraded, the XPC connection keeps failing. Upgrade steps: PreInstall script kills the running processes, both UI and Network Extension Let installation continue PostInstall script to launch the application after installation complete. Following code is successful to the point of resume from UI application NSXPCInterface *exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCUIObject)]; newConnection.exportedInterface = exportedInterface; newConnection.exportedObject = delegate; NSXPCInterface *remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCExtObject)]; newConnection.remoteObjectInterface = remoteObjectInterface; self.currentConnection = newConnection; [newConnection resume]; But it fails to get the object id<IPCExtObject> providerProxy = [self.currentConnection remoteObjectProxyWithErrorHandler:^(NSError *registerError) { }]; Please note, this only fails for M2. For M1, this exact code is running fine. Additionally, if I uninstall the application by dropping it in Trash and then installing the newer version, then too, the application works fine.
4
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983
Dec ’25
XPC Resources
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: Forums subtopic: App & System Services > Processes & Concurrency Forums 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 technote XPC and App-to-App Communication forums post Validating Signature Of XPC Process forums post This forums post summarises the options for bidirectional communication This forums post explains the meaning of the privileged flag XPC is mostly used on macOS but there are a few places where it comes into play on iOS: File Provider extensions can export an XPC service to arbitrary apps. For more about the File Provider side of this, see the NSFileProviderServiceSource protocol. For more about the client side, see the NSFileProviderService class. An app can move part of its code into a helper extension and talk to it using XPC. See Creating enhanced security helper extensions. Alternative browser engines can do a similar thing. See BrowserEngineKit for more about this. Apps with embedded extensions can use XPC via ExtensionFoundation. (Note that on iOS, but not macOS, an app can only use extensions embedded within the app itself.) 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"
0
0
3.4k
2w
Validating Signature Of XPC Process
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
8
0
8.3k
Aug ’25
Unable to log into Developer Account
Beginning yesterday and still continuing when I go to log into my developer account (both iOS and OS X) I am presented with a new Terms and Agreement page. The agreement is not displayed, I am unable to download the PDF and when I check the Agree box then Submit it returns me to the same page. I am unable to contact support as all of the links are invalid or I get kept being sent back tot eh Terms &amp; Agreement page.How do I get out of this black hole?
3
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697
Sep ’25
setCodeSigningRequirement seems not to work in new Service Management API setup.
I have developed a sample app following the example found Updating your app package installer to use the new Service Management API and referring this discussion on XPC Security. The app is working fine, I have used Swift NSXPCConnection in favour of xpc_connection_create_mach_service used in the example. (I am running app directly from Xcode) I am trying to set up security requirements for the client connection using setCodeSigningRequirement on the connection instance. But it fails for even basic requirement connection.setCodeSigningRequirement("anchor apple"). Error is as follows. cannot open file at line 46986 of [554764a6e7] os_unix.c:46986: (0) open(/private/var/db/DetachedSignatures) - Undefined error: 0 xpc_support_check_token: anchor apple error: Error Domain=NSOSStatusErrorDomain Code=-67050 "(null)" status: -67050 I have used codesign -d --verbose=4 /path/to/executable to check the attributes I do get them in the terminal. Other way round, I have tried XPC service provider sending back process id (pid) with each request, and I am probing this id to get attributes using this code which gives all the details. func inspectCodeSignature(ofPIDString pidString: String) { guard let pid = pid_t(pidString) else { print("Invalid PID string: \(pidString)") return } let attributes = [kSecGuestAttributePid: pid] as CFDictionary var codeRef: SecCode? let status = SecCodeCopyGuestWithAttributes(nil, attributes, [], &codeRef) guard status == errSecSuccess, let code = codeRef else { print("Failed to get SecCode for PID \(pid) (status: \(status))") return } var staticCode: SecStaticCode? let staticStatus = SecCodeCopyStaticCode(code, [], &staticCode) guard staticStatus == errSecSuccess, let staticCodeRef = staticCode else { print("Failed to get SecStaticCode (status: \(staticStatus))") return } var infoDict: CFDictionary? if SecCodeCopySigningInformation(staticCodeRef, SecCSFlags(rawValue: kSecCSSigningInformation), &infoDict) == errSecSuccess, let info = infoDict as? [String: Any] { print("🔍 Code Signing Info for PID \(pid):") print("• Identifier: \(info["identifier"] ?? "N/A")") print("• Team ID: \(info["teamid"] ?? "N/A")") if let entitlements = info["entitlements-dict"] as? [String: Any] { print("• Entitlements:") for (key, value) in entitlements { print(" - \(key): \(value)") } } } else { print("Failed to retrieve signing information.") } var requirement: SecRequirement? if SecRequirementCreateWithString("anchor apple" as CFString, [], &requirement) == errSecSuccess, let req = requirement { let result = SecStaticCodeCheckValidity(staticCodeRef, [], req) if result == errSecSuccess { print("Signature is trusted (anchor apple)") } else { print("Signature is NOT trusted by Apple (failed anchor check)") } } var infoDict1: CFDictionary? let signingStatus = SecCodeCopySigningInformation(staticCodeRef, SecCSFlags(rawValue: kSecCSSigningInformation), &infoDict1) guard signingStatus == errSecSuccess, let info = infoDict1 as? [String: Any] else { print("Failed to retrieve signing information.") return } print("🔍 Signing Info for PID \(pid):") for (key, value) in info.sorted(by: { $0.key < $1.key }) { print("• \(key): \(value)") } } If connection.setCodeSigningRequirement does not works I plan to use above logic as backup. Q: Please advise is there some setting required to be enabled or I have to sign code with some flags enabled. Note: My app is not running in a Sandbox or Hardened Runtime, which I want.
Replies
12
Boosts
0
Views
378
Activity
Apr ’25
Sending messages from Google Chrome extension to macOS app
I'm building a macOS Google Chrome extension. I need to be able to send messages from the Chrome extension to the macOS app What's the set up flow? I've heard about native messaging, but I struggle to implement it. I've heard about XPC, but not sure JS can send messages to a macOS XPC service.
Replies
2
Boosts
0
Views
524
Activity
Apr ’25
macOS 14 XPC vs Foundation XPC
I'm looking into a newer XPC API available starting with macOS 14. Although it's declared as a low-level API I can't figure it how to specify code signing requirement using XPCListener and XPCSession. How do I connect it with xpc_listener_set_peer_code_signing_requirement and xpc_connection_set_peer_code_signing_requirement which require xpc_listener_t and xpc_connection_t respectively? Foundation XPC is declared as a high-level API and provides easy ways to specify code signing requirements on both ends of xpc. I'm confused with all these XPC APIs and their future: Newer really high-level XPCListener and XPCSession API (in low-level framework???) Low-level xpc_listener_t & xpc_connection_t -like API. Is it being replaced by newer XPCListener and XPCSession? How is it related to High-level Foundation XPC? Are NSXPCListener and NSXPCConnection going to be deprecated and replaced by XPCListener and XPCSession??
Replies
2
Boosts
0
Views
845
Activity
Aug ’25
Missing flows for content filter on macOS 15 Sequoia
We use as content filter in our app to monitor flows, we gather data about the flow and block flows deemed suspicious. Our content filter is activated/deactivated by a UI app but the flows are reported via XPC to a separate daemon process for analysis. As of macOS 15, we are seeing cases where flows are missing or flows are not received at all by the content filter. The behaviour is not consistent, some devices seem to receive flows normally but others don't. It appears Intel devices are much less prone to showing the problem, whereas Arm devices routinely exhibit missing flows. On macOS 14 or earlier, there is no sign of missing flows. Testing on earlier beta versions of macOS 15 did not appear to show the problem, however I can't rule out if issue was present but it wasn't spotted. Experimenting with simple examples of using a content filter (e.g. QNE2FilterMac) does not appear to reproduce the issue. Questions, What has changed between macOS 14 and 15 that could be the cause of the lack of flows? Is our approach to using an app activated content filter reporting to a daemon connected via XPC unsupported?
Replies
7
Boosts
1
Views
1.1k
Activity
Aug ’25
GUI + XPC Service App Architecture Performance
Let's image that someone wants to use a background service to keep track of FSEvents activity, at the file level (a firehose, some might say). I choose this example, to indicate the volume and rate of data transmission in question. I'm not creating a front-end for FSEvents data, but my background service may generate data at a similar pace. The service runs off of user defined document/s that specify the FSEvent background filtering to be applied. Those that match get stored into a database. But filters can match on almost all the data being emitted by FSEvents. The user decides to check on the service's activity and database writes by launching a GUI that sends requests to the background service using XPC. So the GUI can request historic data from a database, but also get a real-time view of what FS events the service is busy filtering. So it's a client-server approach, that's concerned with monitoring an event stream over XPC. I understand XPC is a request/response mechanism, and I might look into using a reverse connection here, but my main concern is one of performance. Is XPC capable of coping with such a high volume of data transmision? Could it cope with 1000s of rows of table data updates per second sent to a GUI frontend? I know there are streaming protocol options that involve a TCP connection, but I really want to stay away from opening sockets.
Replies
7
Boosts
0
Views
1.2k
Activity
Jan ’26
XPC Connection with Network Extension fails after upgrade
Hi Team, I have a Network Extension application and UI frontend for it. The UI frontend talks to the Network Extension using XPC, as provided by NEMachServiceName. On M2 machine, The application and XPC connection works fine on clean installation. But, when the application is upgraded, the XPC connection keeps failing. Upgrade steps: PreInstall script kills the running processes, both UI and Network Extension Let installation continue PostInstall script to launch the application after installation complete. Following code is successful to the point of resume from UI application NSXPCInterface *exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCUIObject)]; newConnection.exportedInterface = exportedInterface; newConnection.exportedObject = delegate; NSXPCInterface *remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(IPCExtObject)]; newConnection.remoteObjectInterface = remoteObjectInterface; self.currentConnection = newConnection; [newConnection resume]; But it fails to get the object id<IPCExtObject> providerProxy = [self.currentConnection remoteObjectProxyWithErrorHandler:^(NSError *registerError) { }]; Please note, this only fails for M2. For M1, this exact code is running fine. Additionally, if I uninstall the application by dropping it in Trash and then installing the newer version, then too, the application works fine.
Replies
4
Boosts
0
Views
983
Activity
Dec ’25
XPC Resources
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: Forums subtopic: App & System Services > Processes & Concurrency Forums 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 technote XPC and App-to-App Communication forums post Validating Signature Of XPC Process forums post This forums post summarises the options for bidirectional communication This forums post explains the meaning of the privileged flag XPC is mostly used on macOS but there are a few places where it comes into play on iOS: File Provider extensions can export an XPC service to arbitrary apps. For more about the File Provider side of this, see the NSFileProviderServiceSource protocol. For more about the client side, see the NSFileProviderService class. An app can move part of its code into a helper extension and talk to it using XPC. See Creating enhanced security helper extensions. Alternative browser engines can do a similar thing. See BrowserEngineKit for more about this. Apps with embedded extensions can use XPC via ExtensionFoundation. (Note that on iOS, but not macOS, an app can only use extensions embedded within the app itself.) 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"
Replies
0
Boosts
0
Views
3.4k
Activity
2w
Validating Signature Of XPC Process
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
Replies
8
Boosts
0
Views
8.3k
Activity
Aug ’25
Unable to log into Developer Account
Beginning yesterday and still continuing when I go to log into my developer account (both iOS and OS X) I am presented with a new Terms and Agreement page. The agreement is not displayed, I am unable to download the PDF and when I check the Agree box then Submit it returns me to the same page. I am unable to contact support as all of the links are invalid or I get kept being sent back tot eh Terms &amp; Agreement page.How do I get out of this black hole?
Replies
3
Boosts
0
Views
697
Activity
Sep ’25