I am using [SMAppService registerAndReturnError:] to register a launch agent from a plist bundled in the app (before the registration call a matching unregister is done via unregisterWithCompletionHandler as suggested by the docs). The non standard thing is that I am doing that in a root gui login with sudo to bootstrap my launch agent into gui/0 domain.
This worked well until Sonoma 14.4 - now the call fails with:
Error Domain=SMAppServiceErrorDomain Code=125 "Domain does not support specified action" UserInfo={NSLocalizedFailureReason=Domain does not support specified action}
which is not really helpful.
For now, i've switche to just using launchctl bootout and launchctl bootstrap to get around this, but could anyone elaborate on what has changed? My feeling is that something has changed in the logic that determines the domain - could it be that even with sudo the target domain is gui/ not gui/0 ? As far as I can see there are no ways to specify the domain from the SMAppService APIs right? Also a weird thing is that if run the code in a raw terminal in root gui it works as previously (but out of security, no thing really runs as root, everything is a launch agent under some less privileged user, and before Sonoma 14.4 sudoing with that less privileged user did work for [SMAppService registerAndReturn], now it does not, and what is also strange, doing sudo - and then sudo su also shows the same error code 125.
Processes & Concurrency
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I'm calling the following function in a SwiftUI View modifier in Xcode 16.1:
nonisolated function f -> CGFloat {
let semaphore = DispatchSemaphore(value: 0)
var a: CGFloat = 0
DispatchQueue.main.async {
a = ...
semaphore.signal()
}
semaphore.wait()
return a
}
The app freezes, and code in the main queue is never executed.
Let's say I queue some tasks on DispatchQueue.global() and then switch to another app or locking screen for a while. The app was not terminated but stayed in the background.
Is there a chance that some tasks queued but not yet start could be discarded, even if the app hasn’t been terminated, after switching to another app or locking the screen for a while?
Hi,
we are in the process of exploring how to create an installer for our array of apps.
We have come to the conclusion that regular .pkg installers produced by pkgbuild and productbuild are unfulfilling of our expectations. [1]
Regardless, our installer needs to place files at privileged locations (/Library/Application Support) so we are looking into how to best solve this problem, with the user having
the largest clarity on what they are about to do (so no shady "wants to make changes" dialogs)
the least steps to do to install these files in the right place (so no targeted NSSavePanel-s)
Now, we have done our light reading via some nicely collected posts on the topic (https://forums.developer.apple.com/forums/thread/708765 for example) and the single missing option in the list of privilege escalation models seems to be a one-time privilege escalation from a GUI app.
Our reasons for declaring so:
AuthorizationExecuteWithPrivileges is long deprecated and we are trying to build a futureproof solution
NSAppleScript is just putting up a shady ("wants to make changes") dialog when trying something like this:
$ osascript -e "set filePath to \"/Library/Application Support\"" -e "do shell script \"touch \" & the quoted form of filePath & \"/yyy.txt\" with administrator privileges"
Is there another way to request a one-time authorization from the admin to perform such a simple operation as copying a file to a protected location?
I know it's possible to externalize and internalize Authorization Rights, but they are just an interface to create extra rights and use them as barriers, because they don't actually pass the required right to further operations based on this documentation.
Using SMAppService to register a daemon, which has to be manually allowed by the user adds a lot to the complexity of this installation process, and is something we would like to avoid if possible. (And it's also not the right security model if we want to be honest - we don't want ongoing administrator rights and a daemon)
Is there something we haven't taken into consideration?
[1] preinstall scripts run after the choices are presented during installation and we would need advanced logic (not the limited JavaScript system/files API provided by Installer JS) - plus, the GUI is obviously very limited in a .pkg :(
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??
I’ve been experimenting with Dispatch, and workloops in particular. I gather that they’re similar to serial queues, except that they reorder work items by QoS. I suspect there’s more to workloops than meets the eye, though; calling dispatch_set_target_queue on them has no effect, in spite of the <dispatch/workloop.h> saying that workloops “can be passed to all APIs accepting a dispatch queue, except for functions from the dispatch_sync() family”.
Workloops keep showing up in odd places like Metal and Network.framework backtraces, and <dispatch/workloop.h> includes functionality for tying workloops to os_workgroups (?!).
What exactly is a workloop beyond just a serial queue with priority ordering, and why can’t I set the target queue of one?
I've written an app that uses On Idle (RunHandler) to prompt me to get up and stretch every 30 minutes.
Is there anyway to query the running app to determine how long it's been since it last woke up and prompted me? Something like thru the apps properties by right clicking on the icon in the dock?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
All the nuances of when and whether a background task runs aside, does launching the app cancel the currently scheduled refresh task? As an example, consider the following case:
8AM - user launches app. This launch schedules a background refresh for 12 hours later, at 8PM
12PM (noon) - user launches the app, views some content, then exits the app.
Does the scheduled refresh for 8PM still exist, or does the launch at noon invalidate that task, since the refresh could conceivably be handled during that noon launch?
Hopefully this is articulated clearly enough, but I'm trying to understand the specifics of background refresh behavior, since I don't want to run that refresh every time the app is opened. However, if opening the app invalidates scheduled refreshes, I will need to include logic that will reschedule the refresh accordingly.
When using the continuation API, we're required to call resume exactly once. While withCheckedContinuation helps catch runtime issues during debugging, I'm looking for ways to catch such errors at compile time or through tools like Instruments.
Is there any tool or technique that can help enforce or detect this requirement more strictly than runtime checks? Or would creating custom abstractions around Continuation be the only option to ensure safety? Any suggestions or best practices are appreciated.
I have followed this post for creating a Launch Agent that provides an XPC service on macOS using Swift-
post link - https://rderik.com/blog/creating-a-launch-agent-that-provides-an-xpc-service-on-macos/
In the swift code the interface of the XPC service is defined by protocols which makes the code nice and neat. I want to implement the XPC service using C APIs for XPC, and C APIs send and receive messages using dictionaries, which need manual handling with conditional statements.
I want to know if its possible to go with the protocol based approach with C APIs.
I’m currently porting a Chrome Extension to Safari and integrating it with native messaging in a Safari Web Extension. As part of this, I’m building a proxy to forward messages between the web extension and a socket in another application, both ways. Additionally, the socket occasionally broadcasts messages that also need to be sent to the web extension.
The issue I’m facing is that the app extension terminates whenever I call context.completeRequest(returningItems: nil), which prevents me from listening for incoming messages from the socket (I'm using the Network Framework). To work around this, I’ve tried not calling context.completeRequest(returningItems: nil), which keeps the app extension running. However, I’m unsure if this is the right approach—currently, I’m simply ignoring the response and relying entirely on SFSafariApplication.dispatchMessage.
According to the documentation, the app extension lifecycle ends when the system terminates it, but I need to keep the socket listener active.
Has anyone encountered a similar issue, or does anyone have suggestions for maintaining the socket connection while adhering to the app extension lifecycle?
Any insights would be greatly appreciated!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Network
Safari Services
Safari Extensions
This is the functionality I am trying to achieve with libxpc:
There's one xpc server and two xpc clients. When the xpc server receives a particular dictionary item from clientB, the server needs to send a response to both clientA and clientB.
This is the approach I am currently using:
First, clientA creates a dictionary item that indicates that this item is from clientA. Now, clientA sends this dictionary to server. When server receives this item, it stores the connection instance with clientA in a global variable. Next, when clientB sends a particular dictionary item, server uses this global variable where it perviously stored clientA's connection instance to send a response back to clientA, alongside clientB.
Only one edge case I can see is that when clientA closes this connection instance, server will be trying to send a response to an invalidated connection.
Question:
Is this approach recommended? Any edge cases I should be aware of? Is there any better way to achieve this functionality?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Inter-process communication
XPC
Hi all,
Our company has an application that runs on several machines, this app is launched via a deamon that keeps it alive.
One of the feature of this app, is to start a headless electron application to run some tests. When spawning this electron application with the new arm64 OS, we are getting this issue:
Silent Test Agent Worker exited with code: 133
[ERROR] [75873:0205/135842.347044:ERROR:mach_port_rendezvous.cc(384)] bootstrap_look_up com.hivestreaming.silenttestagent.MachPortRendezvousServer.1: Permission denied (1100)
[ERROR] [75873:0205/135842.347417:ERROR:shared_memory_switch.cc(237)] No rendezvous client, terminating process (parent died?)
[ERROR] [75872:0205/135842.347634:ERROR:mach_port_rendezvous.cc(384)] bootstrap_look_up com.hivestreaming.silenttestagent.MachPortRendezvousServer.1: Permission denied (1100)
[ERROR] [75872:0205/135842.347976:ERROR:shared_memory_switch.cc(237)] No rendezvous client, terminating process (parent died?)
Both application (main app and electron one) are signed and notarized, but it seems that there is some other permission issue.
If we run the electron application manually, all runs as expected.
I added the crash report as attachment
CrashReport.log
When I run my app with XCode on my iPhone, and then moved into the background, I'm getting a EXC_BREAKPOINT exception after a few minutes, seemingly when iOS attempts to call my app with a BGAppRefreshTask:
Thread 23 Queue: com.apple.BGTaskScheduler (com.mycompany.MyApp.RefreshTask) (serial)
0 _dispatch_assert_queue_fail
12 _pthread_wqthread
Enqueued from com.apple.duet.activityscheduler.client.xpcqueue (Thread 23)
0 dispatch_async
20 start_wqthread
I can't quite understand the reason from this crash. In the background task, I'm attempting to update live activities. In the process, it might encounter code that calls MainActor and manipulate @Observable objects. Might that be the reason?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Swift
Background Tasks
Observation
I have an app that I'm using for my own purposes and is not in the app store. I would like to run an http server in the background for more than the allotted 3 minutes to allow persistent communications with a connected Bluetooth device. The Bluetooth device would poll the service at intervals. Is this possible to do? This app does not need app store approval since it's only for personal use.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
Foundation
IOBluetooth
Core Bluetooth
My load average on a largely idle system is around 22, going up to 70 or so periodically; SSMenuAgent seems to be consuming lots of CPU (and, looking at spindump, it certainly seems busy), but... it's not happening on any other system whose screens I am observing. (Er, I know about load average limitations, the process is also consuming 70-98% CPU according to both top and Activity Monitor.)
Since this machine (although idle) has our network extension, I'm trying to figure out if this is due to that, or of this is generally expected. Anyone?
Topic:
App & System Services
SubTopic:
Processes & Concurrency
I am using C APIs for XPC communication.
When my XPC server gets a xpc_dictionary as a message, I use xpc_dictionary_get_string to get the string which is of type const char*. Afterwards, when I try to free up the memory for the string, I get an error.
I could not find any details on why this happens.
Does XPC handle the lifecycle of these C strings ?
I did some tests to see the behaviour.
The following code snippet prints a string temp before and after releasing the dictionary memory.
char* string = "dummy-string";
xpc_object_t dict = xpc_dictionary_create(NULL, NULL, 0); xpc_dictionary_set_string(dict, "str", string);
const char* temp = xpc_dictionary_get_string(reply, "str");
printf("temp before release: %s\n", temp);
xpc_release(reply);
printf("temp after release: %s\n", temp);
output:
# temp before release: dummy-string
# temp after release:
I tried to free the variable temp before and after releasing dict .
char* string = "dummy-string";
xpc_object_t dict = xpc_dictionary_create(NULL, NULL, 0); xpc_dictionary_set_string(dict, "str", string);
const char* temp = xpc_dictionary_get_string(dict, "str");
printf("temp before release: %s\n", temp);
free((void *)temp); // case 1
xpc_release(dict);
// free((void *)temp); // case 2
printf("temp after release: %s\n", temp);
in both the cases i got the output:
# temp before release: dummy-string
# app(18502,0x1f02fc840) malloc: Double free of object 0x145004a20
# app(18502,0x1f02fc840) malloc: *** set a breakpoint in malloc_error_break to debug
# SIGABRT: abort
# PC=0x186953720 m=0 sigcode=0
# signal arrived during cgo execution
# ...
# ...
Is the title possible ? I tried [[thread valueForKey:@"_private"] valueForKey:@"tid"] but the tid was not kvc compliant. private apis are alright because this is just for testing remote process thread creation. I already have a working method but it has hardcoded assembly so you can't do anything else.
this question is mainly for Quinn (figured he may know something about this)
Hello Apple Developer Community,
I am developing a medical app that is classified as Class B according to FDA regulations. The app connects to a medical device using Bluetooth Low Energy (BLE) to collect critical medical data such as ECG readings. To ensure accurate data collection and maintain the quality of the medical readings, the app needs to wake up every five minutes in the background and perform tasks for approximately 30 seconds.
I understand that iOS has strict limitations on background execution to preserve battery and system performance. However, due to the medical nature of the app and the need for periodic data collection, I am seeking guidance on the following:
If I can provide documentation that the app is associated with an FDA-approved Class B medical device, would Apple allow more lenient background task execution policies?
Are there specific APIs, such as BackgroundTasks, CoreBluetooth, or other recommended strategies, that could help me achieve this behavior reliably?
Is there a process to apply for an exception or special consideration for medical apps that require periodic background activity?
Any insights or recommendations would be greatly appreciated. Thank you!
Desired Behavior
I want the app to be able to handle multiple Push-to-Start notifications even when it is completely terminated. Each Live Activity should:
Be successfully displayed upon receiving a Push-to-Start notification.
Trigger background tasks to send its update token to the server, regardless of the time interval between notifications.
Problem
I am facing an issue with iOS Live Activities when using Push-to-Start notifications to trigger Live Activities in an app that has been completely terminated. Here’s the detailed scenario:
When the app is completely terminated and I send the first Push-to-Start notification:
The Live Activity is successfully displayed.
didFinishLaunchingWithOptions` is triggered, and background tasks execute correctly, including sending the update token to the server.
When I send consecutive Push-to-Start notifications in quick succession (e.g., within a few seconds or minutes):
Both notifications successfully display their respective Live Activities.
Background tasks are executed correctly for both notifications.
However, when there is a longer interval (e.g., 10 minutes) between two Push-to-Start notifications:
The first notification works perfectly—it displays the Live Activity, triggers didFinishLaunchingWithOptions, and executes background tasks.
The second notification successfully displays the Live Activity but fails to execute any background tasks, such as sending the update token to the server.
My HypothesisI
suspect that iOS might impose a restriction where background runtime for Push-to-Start notifications can only be granted once within a certain time frame after the app has been terminated.
Any insights into why this issue might be occurring or how to ensure consistent background task execution for multiple Push-to-Start notifications would be greatly appreciated!