IOKit.framework

IOKit.framework
Public Framework
Availabile	1.0 – present
Class Prefix	IO, OS
Headers	[headers.cynder.me]

I/O Kit is a low-level framework communicating with hardware or kernel services. Although it is a public framework, Apple discourages anyone using it, and will be rejected from AppStore.

IOService

Code using I/O Kit usually follows this pattern:

// Get the service named "AppleNANDFTL".
CFMutableDictionaryRef matching = IOServiceMatching("AppleNANDFTL");
io_service_t service = IOServiceGetMatchingService(kIOMasterPortDefault, matching);

// Open a connection to the AppleNANDFTL service
io_connect_t connect;
kern_return_t errcode = IOServiceOpen(service, mach_task_self(), 0, &connect);

// Send some message to the service and get the result.
// using one of the IOConnectCall*** methods.
if (errcode == 0) {
  size_t infoSize;
  size_t osize = sizeof(infoSize);
  errcode = IOConnectCallStructMethod(
               connect, 0xFE000200, // selector
               NULL, 0,             // input
               &infoSize, &osize);  // output
  if (errcode == 0) {
    void* info = malloc(infoSize);
    IOConnectCallStructMethod(connect, 0xFE000100, NULL, 0, info, &infoSize);
    // do_something_with(info);
    free(info);
  }

  IOServiceClose(connect);
}

IOObjectRelease(service);

The selectors and input/output depends on the service.

Non-IOService

Besides IOService functions, the user-land I/O Kit also contains other hardware and kernel-related functions, e.g. IOHID (human interface device), OSKext (kernel extension), etc.

Versions

Firmware	2.0	2.1	2.2	3.0	3.1	3.2
Version	388.35	388.46	388.46.7	499.0.37	499.0.49	514.7.2