Bring your driver to iPad with DriverKit

DriverKit Overview

• replacement for IOKit device drivers

• new way to extend the system that is more reliable and secure, running in userspace (no longer in the kernel)

• these driver extensions, also known as dexts, are bundled in apps, and you can easily distribute your apps and drivers on the Mac App Store

• support for:

• Networking

• Block Storage

• Serial

• Audio

• USB

• PCI

• HID

• SCSI controllers

• SCSI Peripherals

AudioDriverKit updates

• register a real-time callback

• get a callback every time an IO operation happens

• use for signal processing

// Declare a IOOperationHandler block to set on the IOUserAudioDevice.
// The block will be called from a real time context when a i/o operation
// occurs on the IOUserAudioStream buffers for the device.
io_operation = ^kern_return_t(IOUserAudioObjectID in_device,
                IOUserAudioIOOperation in_io_operation,
                uint32_t in_io_buffer_frame_size,
                uint64_t in_sample_time,
                uint64_t in_host_time)
{
  // Add custom code to make modifications to the buffers as necessary
  if (in_io_operation == IOUserAudioIOOperationWriteEnd) {
    ...
  } else if (in_io_operation == IOUserAudioIOOperationBeginRead) {
    ...
  }
  return kIOReturnSuccess;
};
this->SetIOOperationHandler(io_operation);

New entitlement (from macOS 12.1)

• if your base target is earlier, use com.apple.developer.driverkit.allow-any-userclient-access

• if your base target is macOS 12.1 or later, use com.apple.developer.driverkit.family.audio

• use com.apple.developer.driverkit.allow-any-userclient-access if you want any app to be able to communicate with your driver

• all com.apple.developer.driverkit.family entitlements are now public for development: they no longer require you to file a request

  • request for distribution here

DriverKit on iPad

• no changes required for existing macOS drivers to be ported to iPad

• USBDriverKit, PCIDriverKit, AudioDriverKit support from iPadOS 16

• requires M1 iPads

• automatic discovery on iPadOS (must use SystemExtensions framework on macOS)