This is my first driver and I have had the devil of a time trying to find any information to help me with this. I beg help with this, since I cannot find any tutorials that will get me over this problem.
I am attempting to write a bridging driver for an older UPS that only communicates via RPC-over-USB rather than the HID Power Device class the OS requires. I have written the basic framework for the driver (details below) and am calling OSSystemExtensionRequest.submitRequest with a request object created by OSSystemExtensionRequest.activationRequest, but the didFailWithError callback is called with OSSystemExtensionErrorDomain of a value of 9, which appears to be a general failure to activate the driver. I can find no other information on how to address this issue, but I presume the issue is one of entitlements in either the entitlements file or Info.plist. I will have more code-based details below.
For testing context, I am testing this on a 2021 iMac (M1) running Sequoia 15.7, and this iMac is on MDM, specifically Jamf. I have disabled SIP and set systemextensionsctl developer on, per the instructions here, and I have compiled and am attempting to debug the app using xcode 26.2. The driver itself targets DriverKit 25, as 26 does not appear to be available in xcode despite hints on google that it's out.
For the software, I have a two-target structure in my xcode project, the main Manager app, which is a swift-ui app that both handles installation/activation of the driver and (if that finally manages to work) handles communication from the driver via its UserClient, and the driver which compiles as a dext. Both apps compile and use automated signing attached to our Apple Development team.
I won't delve into the Manager app much, as it runs even though activation fails, except to include its entitlements file in case it proves relevant
<dict>
<key>com.apple.developer.driverkit.communicates-with-drivers</key>
<true/>
<key>com.apple.developer.system-extension.install</key>
<true/>
<key>com.apple.security.app-sandbox</key>
<true/>
<key>com.apple.security.files.user-selected.read-only</key>
<true/>
</dict>
and the relevant activation code:
func request(_ request: OSSystemExtensionRequest, didFailWithError error: any Error) {
// handling the error, which is always code value 9
}
func activateDriver() {
let request = OSSystemExtensionRequest.activationRequest(forExtensionWithIdentifier: "com.mycompany.driver.bundle.identifier", queue: .main)
request.delegate = self
OSSystemExtensionManager.shared.submitRequest(request)
//...
}
And finally the Manager app has the following capabilities requested for its matching identifier in our Apple Developer Account:
- DriverKit Communicates with Drivers
- System Extension
On the Driver side, I have two major pieces, the main driver class MyDriver, and UserClient class, StatusUserClient. MyDriver derives from IDriverKit/IOService.iig but (in case this is somehow important) does not have the same name as the project/target name MyBatteryDriver. StatusUserClient derives from DriverKit/IOUserClient.iig. I have os_log(OS_LOG_DEFAULT, "trace messages") code in every method of both classes, including the initializers and Start implementations, and the log entries never seem to show up in Console, so I presume that means the OS never tried to load the driver.
Unless I'm looking in the wrong place?
Because I don't think the driver code is the current issue, I won't go into it unless it becomes necessary. As I mentioned above, I think this is a code signing / entitlements issue, but I don't know how to resolve it.
In our Apple Developer account, the Driver's matching identifier has the following capabilities requested:
- DriverKit (development)
- DriverKit Allow Any UserClient (development)
- DriverKit Family HID Device (development) -- NOTE: this is planned for future use, but not yet implemented by my driver code. Could that be part of the problem?
- DriverKit Transport HID (development)
- DriverKit USB Transport (development)
- DriverKit USB Transport - VendorID -- submitted, no response from Apple yet
- HID Virtual Device -- submitted, no response from Apple. yet. This is vestigial from an early plan to build the bridge via shared memory funneling to a virtual HID device. I think I've found a way to do it with one Service, but... not sure yet. Still, that's a problem for tomorrow.
Apparently I've gone over the 7000 character maximum so I will add my entitlements and info.plist contents in a reply.
