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USBPrivateDataSample.c

/*

    File:           USBPrivateDataSample.c

    Description:    This sample demonstrates how to use IOKitLib and IOUSBLib to set up asynchronous

                    callbacks when a USB device is attached to or removed from the system.

                    It also shows how to associate arbitrary data with each device instance.

    Copyright:      © Copyright 2001-2006 Apple Computer, Inc. All rights reserved.

    Disclaimer:     IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.

                    ("Apple") in consideration of your agreement to the following terms, and your

                    use, installation, modification or redistribution of this Apple software

                    constitutes acceptance of these terms.  If you do not agree with these terms,

                    please do not use, install, modify or redistribute this Apple software.

                    In consideration of your agreement to abide by the following terms, and subject

                    to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs

                    copyrights in this original Apple software (the "Apple Software"), to use,

                    reproduce, modify and redistribute the Apple Software, with or without

                    modifications, in source and/or binary forms; provided that if you redistribute

                    the Apple Software in its entirety and without modifications, you must retain

                    this notice and the following text and disclaimers in all such redistributions of

                    the Apple Software.  Neither the name, trademarks, service marks or logos of

                    Apple Computer, Inc. may be used to endorse or promote products derived from the

                    Apple Software without specific prior written permission from Apple.  Except as

                    expressly stated in this notice, no other rights or licenses, express or implied,

                    are granted by Apple herein, including but not limited to any patent rights that

                    may be infringed by your derivative works or by other works in which the Apple

                    Software may be incorporated.

                    The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

                    WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

                    WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

                    PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

                    COMBINATION WITH YOUR PRODUCTS.

                    IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

                    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

                    GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

                    ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION

                    OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT

                    (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN

                    ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    Change History (most recent first):

            1.2     10/04/2006          Updated to produce a universal binary. Now requires Xcode 2.2.1 or

                                        later to build. Modernized and incorporated bug fixes.

            1.1     04/24/2002          Added comments, release of interface object, use of USB location ID

            1.0     10/30/2001          New sample.

*/

#include <CoreFoundation/CoreFoundation.h>

#include <IOKit/IOKitLib.h>

#include <IOKit/IOMessage.h>

#include <IOKit/IOCFPlugIn.h>

#include <IOKit/usb/IOUSBLib.h>

// Change these two constants to match your device's idVendor and idProduct.

// Or, just pass your idVendor and idProduct as command line arguments when running this sample.

#define kMyVendorID         1351

#define kMyProductID        8193

typedef struct MyPrivateData {

    io_object_t             notification;

    IOUSBDeviceInterface    **deviceInterface;

    CFStringRef             deviceName;

    UInt32                  locationID;

} MyPrivateData;

static IONotificationPortRef    gNotifyPort;

static io_iterator_t            gAddedIter;

static CFRunLoopRef             gRunLoop;

//================================================================================================

//

//  DeviceNotification

//

//  This routine will get called whenever any kIOGeneralInterest notification happens.  We are

//  interested in the kIOMessageServiceIsTerminated message so that's what we look for.  Other

//  messages are defined in IOMessage.h.

//

//================================================================================================

void DeviceNotification(void *refCon, io_service_t service, natural_t messageType, void *messageArgument)

    kern_return_t   kr;

    MyPrivateData   *privateDataRef = (MyPrivateData *) refCon;

    if (messageType == kIOMessageServiceIsTerminated) {

        fprintf(stderr, "Device removed.\n");

        // Dump our private data to stderr just to see what it looks like.

        fprintf(stderr, "privateDataRef->deviceName: ");

        CFShow(privateDataRef->deviceName);

        fprintf(stderr, "privateDataRef->locationID: 0x%lx.\n\n", privateDataRef->locationID);

        // Free the data we're no longer using now that the device is going away

        CFRelease(privateDataRef->deviceName);

        if (privateDataRef->deviceInterface) {

            kr = (*privateDataRef->deviceInterface)->Release(privateDataRef->deviceInterface);

        kr = IOObjectRelease(privateDataRef->notification);

        free(privateDataRef);

//================================================================================================

//

//  DeviceAdded

//

//  This routine is the callback for our IOServiceAddMatchingNotification.  When we get called

//  we will look at all the devices that were added and we will:

//

//  1.  Create some private data to relate to each device (in this case we use the service's name

//      and the location ID of the device

//  2.  Submit an IOServiceAddInterestNotification of type kIOGeneralInterest for this device,

//      using the refCon field to store a pointer to our private data.  When we get called with

//      this interest notification, we can grab the refCon and access our private data.

//

//================================================================================================

void DeviceAdded(void *refCon, io_iterator_t iterator)

    kern_return_t       kr;

    io_service_t        usbDevice;

    IOCFPlugInInterface **plugInInterface = NULL;

    SInt32              score;

    HRESULT             res;

    while ((usbDevice = IOIteratorNext(iterator))) {

        io_name_t       deviceName;

        CFStringRef     deviceNameAsCFString;

        MyPrivateData   *privateDataRef = NULL;

        UInt32          locationID;

        printf("Device added.\n");

        // Add some app-specific information about this device.

        // Create a buffer to hold the data.

        privateDataRef = malloc(sizeof(MyPrivateData));

        bzero(privateDataRef, sizeof(MyPrivateData));

        // Get the USB device's name.

        kr = IORegistryEntryGetName(usbDevice, deviceName);

        if (KERN_SUCCESS != kr) {

            deviceName[0] = '\0';

        deviceNameAsCFString = CFStringCreateWithCString(kCFAllocatorDefault, deviceName,

                                                         kCFStringEncodingASCII);

        // Dump our data to stderr just to see what it looks like.

        fprintf(stderr, "deviceName: ");

        CFShow(deviceNameAsCFString);

        // Save the device's name to our private data.

        privateDataRef->deviceName = deviceNameAsCFString;

        // Now, get the locationID of this device. In order to do this, we need to create an IOUSBDeviceInterface

        // for our device. This will create the necessary connections between our userland application and the

        // kernel object for the USB Device.

        kr = IOCreatePlugInInterfaceForService(usbDevice, kIOUSBDeviceUserClientTypeID, kIOCFPlugInInterfaceID,

                                               &plugInInterface, &score);

        if ((kIOReturnSuccess != kr) || !plugInInterface) {

            fprintf(stderr, "IOCreatePlugInInterfaceForService returned 0x%08x.\n", kr);

            continue;

        // Use the plugin interface to retrieve the device interface.

        res = (*plugInInterface)->QueryInterface(plugInInterface, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID),

                                                 (LPVOID*) &privateDataRef->deviceInterface);

        // Now done with the plugin interface.

        (*plugInInterface)->Release(plugInInterface);

        if (res || privateDataRef->deviceInterface == NULL) {

            fprintf(stderr, "QueryInterface returned %d.\n", (int) res);

            continue;

        // Now that we have the IOUSBDeviceInterface, we can call the routines in IOUSBLib.h.

        // In this case, fetch the locationID. The locationID uniquely identifies the device

        // and will remain the same, even across reboots, so long as the bus topology doesn't change.

        kr = (*privateDataRef->deviceInterface)->GetLocationID(privateDataRef->deviceInterface, &locationID);

        if (KERN_SUCCESS != kr) {

            fprintf(stderr, "GetLocationID returned 0x%08x.\n", kr);

            continue;

        else {

            fprintf(stderr, "Location ID: 0x%lx\n\n", locationID);

        privateDataRef->locationID = locationID;

        // Register for an interest notification of this device being removed. Use a reference to our

        // private data as the refCon which will be passed to the notification callback.

        kr = IOServiceAddInterestNotification(gNotifyPort,                      // notifyPort

                                              usbDevice,                        // service

                                              kIOGeneralInterest,               // interestType

                                              DeviceNotification,               // callback

                                              privateDataRef,                   // refCon

                                              &(privateDataRef->notification)   // notification

);

        if (KERN_SUCCESS != kr) {

            printf("IOServiceAddInterestNotification returned 0x%08x.\n", kr);

        // Done with this USB device; release the reference added by IOIteratorNext

        kr = IOObjectRelease(usbDevice);

//================================================================================================

//

//  SignalHandler

//

//  This routine will get called when we interrupt the program (usually with a Ctrl-C from the

//  command line).

//

//================================================================================================

void SignalHandler(int sigraised)

    fprintf(stderr, "\nInterrupted.\n");

    exit(0);

//================================================================================================

//  main

//================================================================================================

int main(int argc, const char *argv[])

    CFMutableDictionaryRef  matchingDict;

    CFRunLoopSourceRef      runLoopSource;

    CFNumberRef             numberRef;

    kern_return_t           kr;

    long                    usbVendor = kMyVendorID;

    long                    usbProduct = kMyProductID;

    sig_t                   oldHandler;

    // pick up command line arguments

    if (argc > 1) {

        usbVendor = atoi(argv[1]);

    if (argc > 2) {

        usbProduct = atoi(argv[2]);

    // Set up a signal handler so we can clean up when we're interrupted from the command line

    // Otherwise we stay in our run loop forever.

    oldHandler = signal(SIGINT, SignalHandler);

    if (oldHandler == SIG_ERR) {

        fprintf(stderr, "Could not establish new signal handler.");

    fprintf(stderr, "Looking for devices matching vendor ID=%ld and product ID=%ld.\n", usbVendor, usbProduct);

    // Set up the matching criteria for the devices we're interested in. The matching criteria needs to follow

    // the same rules as kernel drivers: mainly it needs to follow the USB Common Class Specification, pp. 6-7.

    // See also Technical Q&A QA1076 "Tips on USB driver matching on Mac OS X"

    // <http://developer.apple.com/qa/qa2001/qa1076.html>.

    // One exception is that you can use the matching dictionary "as is", i.e. without adding any matching

    // criteria to it and it will match every IOUSBDevice in the system. IOServiceAddMatchingNotification will

    // consume this dictionary reference, so there is no need to release it later on.

    matchingDict = IOServiceMatching(kIOUSBDeviceClassName);    // Interested in instances of class

                                                                // IOUSBDevice and its subclasses

    if (matchingDict == NULL) {

        fprintf(stderr, "IOServiceMatching returned NULL.\n");

        return -1;

    // We are interested in all USB devices (as opposed to USB interfaces).  The Common Class Specification

    // tells us that we need to specify the idVendor, idProduct, and bcdDevice fields, or, if we're not interested

    // in particular bcdDevices, just the idVendor and idProduct.  Note that if we were trying to match an

    // IOUSBInterface, we would need to set more values in the matching dictionary (e.g. idVendor, idProduct,

    // bInterfaceNumber and bConfigurationValue.

    // Create a CFNumber for the idVendor and set the value in the dictionary

    numberRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &usbVendor);

    CFDictionarySetValue(matchingDict,

                         CFSTR(kUSBVendorID),

                         numberRef);

    CFRelease(numberRef);

    // Create a CFNumber for the idProduct and set the value in the dictionary

    numberRef = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &usbProduct);

    CFDictionarySetValue(matchingDict,

                         CFSTR(kUSBProductID),

                         numberRef);

    CFRelease(numberRef);

    numberRef = NULL;

    // Create a notification port and add its run loop event source to our run loop

    // This is how async notifications get set up.

    gNotifyPort = IONotificationPortCreate(kIOMasterPortDefault);

    runLoopSource = IONotificationPortGetRunLoopSource(gNotifyPort);

    gRunLoop = CFRunLoopGetCurrent();

    CFRunLoopAddSource(gRunLoop, runLoopSource, kCFRunLoopDefaultMode);

    // Now set up a notification to be called when a device is first matched by I/O Kit.

    kr = IOServiceAddMatchingNotification(gNotifyPort,                  // notifyPort

                                          kIOFirstMatchNotification,    // notificationType

                                          matchingDict,                 // matching

                                          DeviceAdded,                  // callback

                                          NULL,                         // refCon

                                          &gAddedIter                   // notification

);

    // Iterate once to get already-present devices and arm the notification

    DeviceAdded(NULL, gAddedIter);

    // Start the run loop. Now we'll receive notifications.

    fprintf(stderr, "Starting run loop.\n\n");

    CFRunLoopRun();

    // We should never get here

    fprintf(stderr, "Unexpectedly back from CFRunLoopRun()!\n");

    return 0;

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