Prints vendor and product ids of USB devices as they are added

usblog.c

//
//  main.c
//  usblog
//

#include <assert.h>
#include <stdio.h>

#import <IOKit/usb/IOUSBLib.h>

// @brief (callback) Called when USB device is added
static void usbDeviceEvent(void *refcon, io_iterator_t iterator)
{
    io_service_t dev;
    kern_return_t kr;

    while (dev = IOIteratorNext(iterator), dev) {
        HRESULT res;
        SInt32 score;
        UInt16 pid, vid;
        IOCFPlugInInterface **plugInInterface = NULL;
        IOUSBDeviceInterface **deviceInterface = NULL;

        kr = IOCreatePlugInInterfaceForService(dev, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &plugInInterface, &score);
        assert(kr == kIOReturnSuccess);
        assert(plugInInterface);

        res = (*plugInInterface)->QueryInterface(plugInInterface, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID), (LPVOID*) &deviceInterface);
        (*plugInInterface)->Release(plugInInterface);
        assert(!res);
        assert(deviceInterface);

        kr = (*deviceInterface)->GetDeviceVendor(deviceInterface, &vid);
        assert(kr == kIOReturnSuccess);
        kr = (*deviceInterface)->GetDeviceProduct(deviceInterface, &pid);
        assert(kr == kIOReturnSuccess);

        fprintf(stderr, "%s: vid = 0x%04x pid = 0x%04x\n", (const char *)refcon, vid, pid);

        kr = IOObjectRelease(dev);
        assert(kr == kIOReturnSuccess);
    }
}

// @brief Main loop
int main(int argc, const char * argv[])
{
    io_iterator_t deviceAddedIterator;
//    io_iterator_t deviceRemovedIterator;
    io_service_t device;
    kern_return_t kr;

    // Create port for receiving I/O Kit notifications
    IONotificationPortRef notifyPort = IONotificationPortCreate(kIOMasterPortDefault);
    assert(notifyPort);

    // Get runloop source for port
    CFRunLoopSourceRef runLoopSource = IONotificationPortGetRunLoopSource(notifyPort);

    // Add source to current runloop
    CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, kCFRunLoopDefaultMode);

    // Matching dictionary for any USB device
    CFDictionaryRef matching = IOServiceMatching(kIOUSBDeviceClassName);

    // Matching dictionary used twice, once for addition and once for removal, so increase reference count
    matching = (CFDictionaryRef)CFRetain(matching);

    // Add matching notifications
    kr = IOServiceAddMatchingNotification(notifyPort, kIOFirstMatchNotification, matching, usbDeviceEvent, "added", &deviceAddedIterator);
    assert(kr == kIOReturnSuccess);
//    kr = IOServiceAddMatchingNotification(notifyPort, kIOTerminatedNotification, matching, usbDeviceEvent, "removed", &deviceRemovedIterator);
//    assert(kr == kIOReturnSuccess);

    // Arm notifications and handle existing devices
    do {
        usbDeviceEvent("added", deviceAddedIterator);
    } while ((device = IOIteratorNext(deviceAddedIterator)));
//    do {
//        usbDeviceEvent("removed", deviceRemovedIterator);
//    } while ((device = IOIteratorNext(deviceRemovedIterator)));

    // Run
    CFRunLoopRun();


    return 0;
}

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