Very Simple XPC

Question

devfunshark OP

Created Dec ’19

Replies 1

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Participants 2

I want to use the XPC technology simply to launch an

app

on macOS. I do not need any interprocess communication, or any of the other feature of XPC.

The only documents that I can find on the internet show a complex structure, with code for the XPC service, separate code to launch the XPC

service via a script, and app code to communicate with the service.

In other words, I only want something that does the equivalent of this:

NSWorkspace.shared.openApplication(at: path, configuration: configuration, completionHandler: nil)

but with XPC. So I would need something along the lines of:

let listener = NSXPCListener.service("/path/to/my_app.app")
listener.resume()
RunLoop.main.run()

Obviously, the service method does not take an argument that would be an executable path, so this does not work.

How can I do that ?

PS: to explain the motivation, launching an XPC service will preserve sandbox restriction form the launching app, whereas launching the app directly via

NSWorkspace.shared.openApplication

will not preserve sandbox restrictions (because the spawned app does not have "com.apple.security.inherit" as entitlement).

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Answer 1

DTS Engineer OP

Apple

Dec ’19

to explain the motivation

Can you explain more of the motivation here? What type of product are you shipping? An app? Or something else? What’s this secondary process you’re trying to launch? Something you created? Or some other code that just happens to already exist on the system? And why does this code need to run outside of the sandbox?

The reason I have all of these questions is that the questions you’ve posed above assume a structure that is far removed from how macOS actually works. It misses a key component of the

launchd

/ XPC architecture, namely that jobs are launched on demand and that XPC, as an IPC mechanism, creates that demand. One does not simply start a

launchd

job, but rather

launchd

knows about all the communication endpoints (of which XPC services are just one type) and it’s the attempt to communicate with that endpoint that causes

launchd

to start the process responsible for that endpoint. In short, XPC without the C makes no sense.

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