Im using the low-level C xpc api <xpc/xpc.h> and i get this error when I run it: Underlying connection interrupted. I know this error stems from the call to xpc_session_send_message_with_reply_sync(session, message, &reply_err);. I have no previous experience with xpc or dispatch and I find the xpc docs very limited and I also found next to no code examples online. Can somebody take a look at my code and tell me what I did wrong and how to fix it? Thank you in advance.
Main code:
#include <stdio.h>
#include <xpc/xpc.h>
#include <dispatch/dispatch.h>
// the context passed to mainf()
struct context {
char* text;
xpc_session_t sess;
};
// This is for later implementation and the name is also rudimentary
void mainf(void* c) {
//char * text = ((struct context*)c)->text;
xpc_session_t session = ((struct context*)c)->sess;
dispatch_queue_t messageq = dispatch_queue_create("y.ddd.main",
DISPATCH_QUEUE_SERIAL);
xpc_object_t message = xpc_dictionary_create(NULL, NULL, 0);
xpc_dictionary_set_string(message, "test", "eeeee");
if (session == NULL) {
printf("Session is NULL\n");
exit(1);
}
__block xpc_rich_error_t reply_err = NULL;
__block xpc_object_t reply;
dispatch_sync(messageq, ^{
reply = xpc_session_send_message_with_reply_sync(session,
message,
&reply_err);
if (reply_err != NULL) printf("Reply Error: %s\n",
xpc_rich_error_copy_description(reply_err));
});
if (reply != NULL)
printf("Reply: %s\n", xpc_dictionary_get_string(reply, "test"));
else printf("Reply is NULL\n");
}
int main(int argc, char* argv[]) {
// Create seperate queue for mainf()
dispatch_queue_t mainq = dispatch_queue_create("y.ddd.main",
DISPATCH_QUEUE_CONCURRENT);
dispatch_queue_t xpcq = dispatch_queue_create("y.ddd.xpc",
NULL);
// Create the context being sent to mainf
struct context* c = malloc(sizeof(struct context));
c->text = malloc(sizeof("Hello"));
strcpy(c->text, "Hello");
xpc_rich_error_t sess_err = NULL;
xpc_session_t session = xpc_session_create_xpc_service("y.getFilec",
xpcq,
XPC_SESSION_CREATE_INACTIVE,
&sess_err);
if (sess_err != NULL) {
printf("Session Create Error: %s\n",
xpc_rich_error_copy_description(sess_err));
xpc_release(sess_err);
exit(1);
}
xpc_release(sess_err);
xpc_session_set_incoming_message_handler(session, ^(xpc_object_t message) {
printf("message recieved\n");
});
c->sess = session;
xpc_rich_error_t sess_ac_err = NULL;
xpc_session_activate(session, &sess_ac_err);
if (sess_err != NULL) {
printf("Session Activate Error: %s\n",
xpc_rich_error_copy_description(sess_ac_err));
xpc_release(sess_ac_err);
exit(1);
}
xpc_release(sess_ac_err);
xpc_retain(session);
dispatch_async_f(mainq, (void*)c, mainf);
xpc_release(session);
dispatch_main();
}
XPC Service code:
#include <stdio.h>
#include <xpc/xpc.h>
#include <dispatch/dispatch.h>
int main(void) {
xpc_rich_error_t lis_err = NULL;
xpc_listener_t listener = xpc_listener_create("y.getFilec",
NULL,
XPC_LISTENER_CREATE_INACTIVE,
^(xpc_session_t sess){
printf("Incoming Session: %s\n", xpc_session_copy_description(sess));
xpc_session_set_incoming_message_handler(sess,
^(xpc_object_t mess) {
xpc_object_t repl = xpc_dictionary_create_empty();
xpc_dictionary_set_string(repl, "test", "test");
xpc_rich_error_t send_repl_err = xpc_session_send_message(sess, repl);
if (send_repl_err != NULL) printf("Send Reply Error: %s\n",
xpc_rich_error_copy_description(send_repl_err));
});
xpc_rich_error_t sess_ac_err = NULL;
xpc_session_activate(sess, &sess_ac_err);
if (sess_ac_err != NULL) printf("Session Activate: %s\n",
xpc_rich_error_copy_description(sess_ac_err));
},
&lis_err);
if (lis_err != NULL) {
printf("Listener Error: %s\n", xpc_rich_error_copy_description(lis_err));
xpc_release(lis_err);
}
xpc_rich_error_t lis_ac_err = NULL;
xpc_listener_activate(listener, &lis_ac_err);
if (lis_ac_err != NULL) {
printf("Listener Activate Error: %s\n", xpc_rich_error_copy_description(lis_ac_err));
xpc_release(lis_ac_err);
}
dispatch_main();
}
XPC
RSS for tagXPC is a a low-level (libSystem) interprocess communication mechanism that is based on serialized property lists.
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I'm working on an XPC server and need to determine the owner of the client process that connects to it. Specifically, I'd like to retrieve details such as the fully qualified user name or other identifying information from the XPC client connection.I'm considering using xpc_connection_get_pid() to get the client’s process ID, but I’m unsure of the best way to map this to the user who owns the process.
Is there a recommended API or approach to capture this information securely?
I have implemented a XPC server using C APIs. I want to write unit tests for it.
I came across the following links that use Swift APIs-
Testing and Debugging XPC Code With an Anonymous Listener
TN3113
I have tried to write anonymous listener code and the client code in the same file, using C APIs-
#include <unistd.h>
#include <syslog.h>
#include <pthread.h>
#include <stdio.h>
#include <xpc/xpc.h>
#include <xpc/connection.h>
#include <CoreFoundation/CoreFoundation.h>
static void Anon_Client_Connection_Handler(xpc_connection_t connection, xpc_object_t clientMessage)
{
const char *description = xpc_copy_description(clientMessage);
printf("Event received - %s\n", description);
free((void *)description);
xpc_type_t type = xpc_get_type(clientMessage);
if (type == XPC_TYPE_ERROR)
{
if (clientMessage == XPC_ERROR_CONNECTION_INVALID)
printf("Client_Connection_Handler received invalid connection n");
else if (clientMessage == XPC_ERROR_TERMINATION_IMMINENT)
printf("Client_Connection_Handler received termination notice n");
}
else
{
const char *clientMsg = xpc_dictionary_get_string(clientMessage, "message");
printf("Received from client: %s ", clientMsg);
}
}
static void Anon_Listener_Connection_Handler(xpc_connection_t connection)
{
printf("Anon_Listener_Connection_Handler called, setting up event handler \n");
xpc_connection_set_event_handler(connection, ^(xpc_object_t clientMessage) {
printf("Processing the connection! \n");
Anon_Client_Connection_Handler(connection, clientMessage);
});
xpc_connection_resume(connection);
}
int main(int argc, const char *argv[])
{
xpc_connection_t anon_listener = xpc_connection_create(NULL, NULL);
xpc_connection_set_event_handler(anon_listener, ^(xpc_object_t clientConnection) {
printf("Client tried to connect \n");
Anon_Listener_Connection_Handler(clientConnection);
});
xpc_connection_resume(anon_listener);
printf("\nINFO Anonymous connection resumed");
xpc_object_t anon_endpoint = xpc_endpoint_create(anon_listener);
xpc_connection_t clientConnection = xpc_connection_create_from_endpoint(anon_endpoint);
xpc_object_t message = xpc_dictionary_create(NULL, NULL, 0);
xpc_dictionary_set_string(message, "message", "client's message");
xpc_connection_send_message_with_reply(clientConnection, message, dispatch_get_main_queue(), ^(xpc_object_t event) {
printf("\nINFO inside reply");
const char *description = xpc_copy_description(event);
printf("\nINFO %s",description);
free((void *)description);
});
xpc_release(message);
xpc_release(anon_listener);
printf("\nINFO Releasing listener");
xpc_release(anon_endpoint);
printf("\nINFO Releasing endpoint");
// dispatch_main();
return 0;
}
and this is the output I get
INFO Anonymous connection resumed
INFO Releasing listener
INFO Releasing endpoint
I am not able to connect to the client and exchange messages. Where am I going wrong?
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 two privileged service(s) and a desktop app. The privileged services are packaged into /Library/*** and are run using launchd at runtime. The desktop app is just dropped into /Applications.
The desktop app connects to one of the services (let's say service "B") via XPC. That is, B is running an XPC listener (using libxpc). Both applications are written in golang with xpc interaction via CGO.
This is all working fine: The desktop app is receiving notifications over XPC from service B. However, during our build we dump the built and signed apps (before .pkg'ing) into a dist folder. When we run the app (using a makefile target), we copy the services from dist to another location as root, then execute the binaries directly. This is problematic for the desktop app, because my understanding is that XPC requires launchd to assert the namespace it's under. Thus, when service B is launched this way, it says "operation not permitted." We also want to reserve the ability to run a production version of our app on the same machine (drink our own champagne and all that), and I would like to avoid having development versions running on startup, so I don't want to use the same launch configurations.
MacOS is one of three platforms we support (linux, windows as well). Our IPC implementation under MacOS uses XPC via golang build tags.
Questions:
Is it possible to start the XPC server without using launchd, or by using launchd but without registering it as an actual service?
Is this a use case where using a unix domain socket would be better (albeit i feel like securing the socket between the privileged / unprivileged process would be ... fun).
Additional / somewhat unrelated questions:
is it possible for me to somehow restrict another process from chatting with service B over XPC (restrict to my other desktop app)?
This is an app bundle question, so very unrelated: The service "app" that contains services A and B is in /Library, with the plist pointing to A, but B resides in Contents/MacOS next to A. Should this be split out into its own app bundle under Frameworks, or is this fine?
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
# ...
# ...
There is one xpc server and two xpc clients (clientA and clientB). When clientB sends a message to the xpc server, xpc server fills a value for dummyString in it's memory and I want clientA to know that dummyString got updated and also the new value for this dummyString. The updation of dummyString is not something that happens often.
Two options we tried:
Have a timer for 5 seconds in clientA and keep polling and request for the value of this dummyString.
Setup a darwin notification in server that gets posted whenever dummyString is being updated. clientA receives requests for dummyString value only when it observes a notification being posted.
Which of these two approaches causes the least delay for clientA to know the updated value of dummyString?
I have 2 XPC clients and an XPC server. One of the XPC clients is a binary-helper that serves as a native messaging host for the browserExtension. The other XPC client sends a specific event to the XPC server, which then triggers a Darwin notification. The binary-helper observes this Darwin notification and sends a response to the browserExtension.
Currently, we're considering two options to communicate the response from binary-helper to browserExtension:
Polling: Every 5 seconds, the browserExtension checks for a response.
Darwin Notifications: The binary-helper sends a message to the browserExtension as soon as it observes the Darwin notification.
I'm wondering if Darwin notifications are fast enough to reliably deliver this response to the browserExtension in real time, or if polling would be a more reliable approach. Any insights or experiences with using Darwin notifications in a similar scenario would be greatly appreciated.
I'm using libxpc in a C server and Swift client. I set up a code-signing requirement in the server using xpc_connection_set_peer_code_signing_requirement(). However, when the client doesn't meet the requirement, the server just closes the connection, and I get XPC_ERROR_CONNECTION_INTERRUPTED on the client side instead of XPC_ERROR_PEER_CODE_SIGNING_REQUIREMENT, making debugging harder.
What I want:
To receive XPC_ERROR_PEER_CODE_SIGNING_REQUIREMENT on the client when code-signing fails, for better debugging.
What I’ve tried:
Using xpc_connection_set_peer_code_signing_requirement(), but it causes the connection to be dropped immediately.
Questions:
Why does the server close the connection without sending the expected error?
How can I receive the correct error on the client side?
Are there any other methods for debugging code-signing failures with libxpc?
Thanks for any insights!
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
XPC
Signing Certificates
Code Signing
On my MAC, I have a XPC server running as a daemon. It also checks the clients for codesigning requirements.
I have multiple clients(2 or more).
Each of these clients periodically(say 5 seconds) poll the XPC server to ask for a particular data.
I want to understand how the performance of my MAC will be affected when multiple XPC clients keep polling a XPC server.
I have created a XPC server and client using C APIs. I want to ensure that I trust the client, so I want to have a codesigning requirement on the server side, something like -
xpc_connection_set_peer_code_signing_requirement(listener, "anchor apple generic and certificate leaf[subject.OU] = \"1234567\"")
This checks if the client code was signed by a code-signing-identity issued by Apple and that the teamID in the leaf certificate is 1234567.
My questions are-
Is using teamID as a signing requirement enough? What else can I add to this requirement to make it more secure?
How does xpc_connection_set_peer_code_signing_requirement work internally? Does it do any cryptographic operations to verify the clients signature or does it simply do string matching on the teamID?
Is there a way actually verify the clients signature(cryptographically) before establishing a connection with the server? (so we know the client is who he claims to be)
Topic:
Code Signing
SubTopic:
Certificates, Identifiers & Profiles
Tags:
XPC
Signing Certificates
Code Signing
Hi! I've been developing iOS and macOS apps for many years, but now I am looking to dive into smth i have never touched before, namely privileged helpers, and i am struggling hard trying to find my footing.
Here’s my use case: I have a CLI tool that requires elevated privileges. I want to create a menu bar app that can interact with this tool, but I’m struggling to find solid documentation or examples of how to accomplish this using SMAppService. I might just be missing something obvious.
If anyone could point me toward relevant documentation, examples, articles, tutorials, or even a WWDC session that covers running privileged helpers with SMAppService, I would greatly appreciate it.
Thanks in advance!
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
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.
In the macOS 14.0 SDK, environment and library constraints were introduced, which made defense against common attack vectors relatively simple (especially with the LightWeightCodeRequirements framework added in 14.4).
Now, the application I'm working on must support macOS 13.0 too, so I was looking into alternatives that do work for those operating systems as well.
What I found myself is that the SecCode/SecStaticCode APIs in the Security Framework do offer very similar fashion checks as the LightWeightCodeRequirements framework does:
SecCodeCopySigningInformation can return values like signing identifier, team identifier, code requirement string and so on.
SecStaticCodeCreateWithPath can return a SecStaticCode object to an executable/app bundle on the file system.
Let's say, I would want to protect myself against launchd executable swap.
From macOS 14.0 onward, I would use a Spawn Constraint for this, directly in the launchd.plist file.
Before macOS 14.0, I would create a SecStaticCode object for the executable path found in the launchd.plist, and then examine its SecCodeCopySigningInformation dictionary. If the expectations are met, only then would I execute the launchd.plist-defined executable or connect to it via XPC.
Are these two equivalent? If not, what are the differences?
I have several processes maintaining NSXPConnection to an XPC service. The connections are bi-directional. Each side service and clients) of the connection exports an object, and an XPCInterface. The @protocols are different - to the service, and from the service to clients.
So long as all the "clients" fully implement their "call-back" @protocol, there's no problem. All works fine.
However - If a client does NOT implement a method in the "call back protocol", or completely neglects to export an object, or interface - and the service attempts to call back using the nonexistent method -- the XPC connection invalidates immediately.
So far - expected behaviour.
However, if I want the service to behave to the client a little like a "delegate" style -- and check first whether the client "respondsToSelector" or even - supports an interface BEFORE calling it, then this doesn't work.
When my XPC service tries the following on a client connection:
if (xpcConnection.remoteObjectInterface == nil)
os_log_error(myXPCLog, "client has no remote interface);
the condition is never met - i.e. the "remoteObjectInterface is never nil even when the client does NOT configure its NSXPCConnection with any incoming NSXPCInterface, and does not set an "exportedObject"
Furthermore, the next check:
if ([proxy respondsToSelector:@selector(downloadFiltersForCustomer:withReply:)]) {
}
will not only fail - but will drop the connection. The client side gets the invalidation with the following error:
<NSXPCConnection: 0x600000b20000> connection to service with pid 2477 named com.proofpoint.ecd: received an undecodable message for proxy 1 (no exported object to receive message). Dropping message.
I guess the "undecidable message" is the respondsToSelector - because the code doesn't get to attempt anything else afterwards, the connection drops.
Is there a way to do this check "quietly", or suffering only "interruption", but without losing the connection,
I'm attempting to install a NetworkExtension as a system extension, using the OSSystemExtensionManager.shared.submitRequest(request) API call. I can see from console logs and systemextensionsctl that my system extension is getting installed, but the OSSystemExtensionRequestDelegate I attach to the request never gets a callback.
In the console logs I see:
com.apple.sx default 14:13:25.811827+0400 sysextd activateDecision found entry to replace: com.coder.Coder-Desktop.VPN, BundleVersion(CFBundleShortVersionString: "1.0", CFBundleVersion: "1")
default 14:13:25.811888+0400 sysextd initial activation decision: requestAppReplaceAction(<sysextd.Extension: 0xa94030100>)
com.apple.sx default 14:13:25.811928+0400 sysextd notifying client of activation conflict
com.apple.xpc default 14:13:25.812156+0400 Coder Desktop [0x154f2d5b0] invalidated because the current process cancelled the connection by calling xpc_connection_cancel()
com.apple.xpc default 14:13:25.813924+0400 sysextd [0xa941d4280] invalidated because the client process (pid 2599) either cancelled the connection or exited
com.apple.sx default 14:13:25.814027+0400 sysextd client connection (pid 2599) invalidated
It appears that something within my app process is cancelling the XPC connection to sysextd, but I'm certainly not calling it from within my code. Presumably something within the OSSystemExtension* APIs are cancelling the connection but I don't know why. It seems to be happening very quickly (within a few hundred ms) after sending the request, and before sysextd can reply.
What could cause this connection to be canceled?
Hello, I'm developing a Mac application that uses a network extension. I'm trying to implement XPC to pass data between my main app and system extension and I'm using the SimpleFirewall demo app as a guide to do this. One thing I can't understand is how the ViewController in the SimpleFirewall main app has access to the class IPCConnection in the SimpleFirewallExtension without it being public and without SimpleFirewallExtension being imported in ViewController.
Topic:
App & System Services
SubTopic:
Processes & Concurrency
Tags:
XPC
System Extensions
Network Extension
hello everyone
On iOS18.0+, app crashed at BSXPCCnx:com.apple.backboard.hid-services.xpc (BSCnx:client:BKHIDEventDeliveryObserver) when app enter background sometimes
crash stacktrace:
Crashed: BSXPCCnx:com.apple.backboard.hid-services.xpc (BSCnx:client:BKHIDEventDeliveryObserver)
0 libsystem_pthread.dylib 0x4078 pthread_mutex_lock + 12
1 ilink_live 0xbd884 (缺少 UUID 973fe6c5058c35bda98679b0c8aa0129)
2 ilink_live 0xb75fc (缺少 UUID 973fe6c5058c35bda98679b0c8aa0129)
3 libsystem_c.dylib 0x23190 __cxa_finalize_ranges + 492
4 libsystem_c.dylib 0x22f8c exit + 32
5 BackBoardServices 0x31b78 -[BKSHIDEventObserver init] + 98
6 BoardServices 0x1dc78 __31-[BSServiceConnection activate]_block_invoke.182 + 128
7 BoardServices 0x1beb4 __61-[BSXPCServiceConnectionEventHandler _connectionInvalidated:]_block_invoke + 196
8 BoardServices 0x4a58 BSXPCServiceConnectionExecuteCallOut + 240
9 BoardServices 0x1d6e8 -[BSXPCServiceConnectionEventHandler _connectionInvalidated:] + 180
10 libdispatch.dylib 0x2248 _dispatch_call_block_and_release + 32
11 libdispatch.dylib 0x3fa8 _dispatch_client_callout + 20
12 libdispatch.dylib 0xb5cc _dispatch_lane_serial_drain + 768
13 libdispatch.dylib 0xc158 _dispatch_lane_invoke + 432
14 libdispatch.dylib 0xb42c _dispatch_lane_serial_drain + 352
15 libdispatch.dylib 0xc158 _dispatch_lane_invoke + 432
16 libdispatch.dylib 0x1738c _dispatch_root_queue_drain_deferred_wlh + 288
17 libdispatch.dylib 0x16bd8 _dispatch_workloop_worker_thread + 540
18 libsystem_pthread.dylib 0x3680 _pthread_wqthread + 288
19 libsystem_pthread.dylib 0x1474 start_wqthread + 8
when crash happened ,most of time app recieved CBManagerStateResetting and CBManagerStateUnsupported event
i would appreciate any insights or recommendations on how to resolve this issue
thx
crash_stacktrace.txt
Hi,
I'm trying to create a launch daemon that uses XPC to receive requests from an unprivileged app. Ultimately both components will be written in Go. For now I'm trying to write a PoC in Objective-C to make sure I get everything right, so I'm compiling / signing from the CLI, and writing plist files by hand -- I'm not using XCode.
My current daemon code is pretty much the same as the boilerplate code that XCode generates when creating a new 'XPC Service':
#import <stdio.h>
#include <xpc/xpc.h>
int main(int argc, char *argv[]) {
xpc_rich_error_t error;
dispatch_queue_t queue = dispatch_queue_create("com.foobar.daemon", DISPATCH_QUEUE_SERIAL);
xpc_listener_t listener = xpc_listener_create(
"com.foobar.daemon",
queue,
XPC_LISTENER_CREATE_NONE,
^(xpc_session_t _Nonnull peer) {
xpc_session_set_incoming_message_handler(peer, ^(xpc_object_t _Nonnull message) {
int64_t firstNumber = xpc_dictionary_get_int64(message, "firstNumber");
int64_t secondNumber = xpc_dictionary_get_int64(message, "secondNumber");
// Create a reply and send it back to the client.
xpc_object_t reply = xpc_dictionary_create_reply(message);
xpc_dictionary_set_int64(reply, "result", firstNumber + secondNumber);
xpc_rich_error_t replyError = xpc_session_send_message(peer, reply);
if (replyError) {
printf("Reply failed, error: %s", xpc_rich_error_copy_description(replyError));
}
});
},
&error);
if (error != NULL) {
printf("ERROR: %s\n", xpc_rich_error_copy_description(error));
exit(1);
}
printf("Created listener: %s", xpc_listener_copy_description(listener));
// Resuming the serviceListener starts this service. This method does not return.
dispatch_main();
return 0;
}
I'm compiling, signing and installing my daemon with the following commands:
build_foobar() {
clang -Wall -x objective-c -o com.foobar.daemon poc/main.m
codesign --force --verify --verbose --options=runtime \
--identifier="com.foobar.daemon" \
--sign="Mac Developer: Albin Kerouanton (XYZ)" \
--entitlements=poc/entitlements.plist \
com.foobar.daemon
}
install_foobar() {
sudo cp com.foobar.daemon /Library/PrivilegedHelperTools/com.foobar.daemon
sudo cp poc/com.foobar.daemon.plist /Library/LaunchDaemons/com.foobar.daemon.plist
sudo launchctl bootout system/com.foobar.daemon || true
sudo launchctl bootstrap system /Library/LaunchDaemons/com.foobar.daemon.plist
}
Here's the content of my entitlements.plist file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>com.apple.application-identifier</key>
<string>ABCD.com.foobar.daemon</string>
</dict>
</plist>
And finally, here's my launchd plist file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Label</key>
<string>com.foobar.daemon</string>
<key>Program</key>
<string>/Library/PrivilegedHelperTools/com.foobar.daemon</string>
<key>ProgramArguments</key>
<array>
<string>/Library/PrivilegedHelperTools/com.foobar.daemon</string>
</array>
<key>RunAtLoad</key>
<false/>
<key>StandardOutPath</key>
<string>/tmp/com.foobar.daemon.out.log</string>
<key>StandardErrorPath</key>
<string>/tmp/com.foobar.daemon.err.log</string>
<key>Debug</key>
<true/>
</dict>
</plist>
Whenever I start my service using sudo launchctl start com.foobar.daemon, it exits with the following error message:
ERROR: Unable to activate listener: failed at listener activation with error 1 - Operation not permitted
System logs don't show anything interesting -- they're just repeating the same error message. I tried to add / remove some properties from both the entitlement and the launchd plist file but to no avail.
Any idea what's going wrong?