使用 IOKit 监听 Mac 电脑的 USB 事件

#import <IOKit/usb/IOUSBLib.h>
#import <IOKit/IOCFPlugIn.h>

// The following code will return an array having configured Ids and Name of all the mounted USB devices.
-(NSArray *) deviceAttributes {

    mach_port_t masterPort;
    CFMutableDictionaryRef matchingDict;
    NSMutableArray * devicesAttributes = [NSMutableArray array];
    kern_return_t kr;

    // Create a master port for communication with the I/O Kit
    kr = IOMasterPort (MACH_PORT_NULL, &masterPort);
    if (kr || !masterPort) {
        NSLog (@"Error: Couldn't create a master I/O Kit port(%08x)", kr);
        return devicesAttributes;
    }

    // Set up matching dictionary for class IOUSBDevice and its subclasses
    matchingDict = IOServiceMatching (kIOUSBDeviceClassName);
    if (!matchingDict) {
        NSLog (@"Error: Couldn't create a USB matching dictionary");
        mach_port_deallocate(mach_task_self(), masterPort);
        return devicesAttributes;
    }

    io_iterator_t iterator;
    IOServiceGetMatchingServices (kIOMasterPortDefault, matchingDict, &iterator);
    io_service_t usbDevice;

    // Iterate for USB devices
    while (usbDevice = IOIteratorNext (iterator)) {
        IOCFPlugInInterface**plugInInterface = NULL;
        SInt32 theScore;

        // Create an intermediate plug-in
        kr = IOCreatePlugInInterfaceForService(usbDevice, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID, &plugInInterface, &theScore);

        if ((kIOReturnSuccess != kr) || !plugInInterface)
            printf("Unable to create a plug-in (%08x)\n", kr);

        IOUSBDeviceInterface182 **dev = NULL;

        // Create the device interface
        HRESULT result = (*plugInInterface)->QueryInterface(plugInInterface, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID), (LPVOID)&dev);

        if (result || !dev)
            printf("Couldn't create a device interface (%08x)\n", (int) result);

        UInt16 vendorId;

        UInt16 productId;

        UInt16 releaseId;

        // Get configuration Ids of the device
        (*dev)->GetDeviceVendor(dev, &vendorId);
        (*dev)->GetDeviceProduct(dev, &productId);
        (*dev)->GetDeviceReleaseNumber(dev, &releaseId);

        UInt8 stringIndex;

        (*dev)->USBGetProductStringIndex(dev, &stringIndex);

        IOUSBConfigurationDescriptorPtr descriptor;

        (*dev)->GetConfigurationDescriptorPtr(dev, stringIndex, &descriptor);

        // Get Device name
        io_name_t deviceName;

        kr = IORegistryEntryGetName (usbDevice, deviceName);

        if (kr != KERN_SUCCESS) {
            NSLog (@"fail 0x%8x", kr);
            deviceName[0] = '\0';
        }

        NSString * name = [NSStringstringWithCString:deviceName encoding:NSASCIIStringEncoding];

        // data will be initialized only for USB storage devices.
        // bsdName can be converted to mounted path of the device and vice-versa using DiskArbitration framework, hence we can identify the device through it's mounted path

        CFTypeRef data = IORegistryEntrySearchCFProperty(usbDevice, kIOServicePlane, CFSTR("BSD Name"), kCFAllocatorDefault, kIORegistryIterateRecursively);

        NSString* bsdName = [(NSString*)data substringToIndex:5];

        NSString* attributeString = @"";
        if(bsdName)
            attributeString = [NSString stringWithFormat:@"%@,%@,0x%x,0x%x,0x%x", name, bsdName, vendorId, productId, releaseId];
        else
            attributeString = [NSString stringWithFormat:@"%@,0x%x,0x%x,0x%x", name, vendorId, productId, releaseId];

        [devicesAttributes addObject:attributeString];
        IOObjectRelease(usbDevice);

        (*plugInInterface)->Release(plugInInterface);

        (*dev)->Release(dev);
    }

    // Finished with master port

    mach_port_deallocate(mach_task_self(), masterPort);

    masterPort = 0;

    return devicesAttributes;
}