fastboot/usb_osx.cpp - LeafOS-Project/android_system_core - Gitiles

 /*
  * Copyright (C) 2008 The Android Open Source Project
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *  * Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *  * Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */

 #include <inttypes.h>
 #include <stdio.h>
 #include <CoreFoundation/CoreFoundation.h>
 #include <IOKit/IOKitLib.h>
 #include <IOKit/IOCFPlugIn.h>
 #include <IOKit/usb/IOUSBLib.h>
 #include <IOKit/IOMessage.h>
 #include <mach/mach_port.h>

 #include <memory>

 #include "usb.h"


 /*
  * Internal helper functions and associated definitions.
  */

 #if TRACE_USB
 #define WARN(x...) fprintf(stderr, x)
 #else
 #define WARN(x...)
 #endif

 #define ERR(x...) fprintf(stderr, "ERROR: " x)

 /** An open usb device */
 struct usb_handle
 {
     int success;
     ifc_match_func callback;
     usb_ifc_info info;

     UInt8 bulkIn;
     UInt8 bulkOut;
     IOUSBInterfaceInterface500** interface;
     unsigned int zero_mask;
 };

 class OsxUsbTransport : public UsbTransport {
   public:
     // A timeout of 0 is blocking
     OsxUsbTransport(std::unique_ptr<usb_handle> handle, uint32_t ms_timeout = 0)
         : handle_(std::move(handle)), ms_timeout_(ms_timeout) {}
     ~OsxUsbTransport() override;

     ssize_t Read(void* data, size_t len) override;
     ssize_t Write(const void* data, size_t len) override;
     int Close() override;
     int Reset() override;

   private:
     std::unique_ptr<usb_handle> handle_;
     const uint32_t ms_timeout_;

     DISALLOW_COPY_AND_ASSIGN(OsxUsbTransport);
 };

 /** Try out all the interfaces and see if there's a match. Returns 0 on
  * success, -1 on failure. */
 static int try_interfaces(IOUSBDeviceInterface500** dev, usb_handle* handle) {
     IOReturn kr;
     IOUSBFindInterfaceRequest request;
     io_iterator_t iterator;
     io_service_t usbInterface;
     IOCFPlugInInterface **plugInInterface;
     IOUSBInterfaceInterface500** interface = NULL;
     HRESULT result;
     SInt32 score;
     UInt8 interfaceNumEndpoints;

     request.bInterfaceClass = 0xff;
     request.bInterfaceSubClass = 0x42;
     request.bInterfaceProtocol = 0x03;
     request.bAlternateSetting = kIOUSBFindInterfaceDontCare;

     // Get an iterator for the interfaces on the device
     kr = (*dev)->CreateInterfaceIterator(dev, &request, &iterator);

     if (kr != 0) {
         WARN("Couldn't create a device interface iterator: (%08x)\n", kr);
         return -1;
     }

     while ((usbInterface = IOIteratorNext(iterator))) {
         // Create an intermediate plugin
         kr = IOCreatePlugInInterfaceForService(
                 usbInterface,
                 kIOUSBInterfaceUserClientTypeID,
                 kIOCFPlugInInterfaceID,
                 &plugInInterface,
                 &score);

         // No longer need the usbInterface object now that we have the plugin
         (void) IOObjectRelease(usbInterface);

         if ((kr != 0) || (!plugInInterface)) {
             WARN("Unable to create plugin (%08x)\n", kr);
             continue;
         }

         // Now create the interface interface for the interface
         result = (*plugInInterface)
                          ->QueryInterface(plugInInterface,
                                           CFUUIDGetUUIDBytes(kIOUSBInterfaceInterfaceID500),
                                           (LPVOID*)&interface);

         // No longer need the intermediate plugin
         (*plugInInterface)->Release(plugInInterface);

         if (result || !interface) {
             ERR("Couldn't create interface interface: (%08x)\n",
                (unsigned int) result);
             // continue so we can try the next interface
             continue;
         }

         /*
          * Now open the interface. This will cause the pipes
          * associated with the endpoints in the interface descriptor
          * to be instantiated.
          */

         /*
          * TODO: Earlier comments here indicated that it was a bad
          * idea to just open any interface, because opening "mass
          * storage endpoints" is bad. However, the only way to find
          * out if an interface does bulk in or out is to open it, and
          * the framework in this application wants to be told about
          * bulk in / out before deciding whether it actually wants to
          * use the interface. Maybe something needs to be done about
          * this situation.
          */

         kr = (*interface)->USBInterfaceOpen(interface);

         if (kr != 0) {
             WARN("Could not open interface: (%08x)\n", kr);
             (void) (*interface)->Release(interface);
             // continue so we can try the next interface
             continue;
         }

         // Get the number of endpoints associated with this interface.
         kr = (*interface)->GetNumEndpoints(interface, &interfaceNumEndpoints);

         if (kr != 0) {
             ERR("Unable to get number of endpoints: (%08x)\n", kr);
             goto next_interface;
         }

         // Get interface class, subclass and protocol
         if ((*interface)->GetInterfaceClass(interface, &handle->info.ifc_class) != 0 ||
             (*interface)->GetInterfaceSubClass(interface, &handle->info.ifc_subclass) != 0 ||
             (*interface)->GetInterfaceProtocol(interface, &handle->info.ifc_protocol) != 0)
         {
             ERR("Unable to get interface class, subclass and protocol\n");
             goto next_interface;
         }

         handle->info.has_bulk_in = 0;
         handle->info.has_bulk_out = 0;

         // Iterate over the endpoints for this interface and see if there
         // are any that do bulk in/out.
         for (UInt8 endpoint = 1; endpoint <= interfaceNumEndpoints; endpoint++) {
             UInt8   transferType;
             UInt16  maxPacketSize;
             UInt8   interval;
             UInt8   number;
             UInt8   direction;

             kr = (*interface)->GetPipeProperties(interface, endpoint,
                     &direction,
                     &number, &transferType, &maxPacketSize, &interval);

             if (kr == 0) {
                 if (transferType != kUSBBulk) {
                     continue;
                 }

                 if (direction == kUSBIn) {
                     handle->info.has_bulk_in = 1;
                     handle->bulkIn = endpoint;
                 } else if (direction == kUSBOut) {
                     handle->info.has_bulk_out = 1;
                     handle->bulkOut = endpoint;
                 }

                 if (handle->info.ifc_protocol == 0x01) {
                     handle->zero_mask = maxPacketSize - 1;
                 }
             } else {
                 ERR("could not get pipe properties for endpoint %u (%08x)\n", endpoint, kr);
             }

             if (handle->info.has_bulk_in && handle->info.has_bulk_out) {
                 break;
             }
         }

         if (handle->callback(&handle->info) == 0) {
             handle->interface = interface;
             handle->success = 1;

             /*
              * Clear both the endpoints, because it has been observed
              * that the Mac may otherwise (incorrectly) start out with
              * them in bad state.
              */

             if (handle->info.has_bulk_in) {
                 kr = (*interface)->ClearPipeStallBothEnds(interface,
                         handle->bulkIn);
                 if (kr != 0) {
                     ERR("could not clear input pipe; result %x, ignoring...\n", kr);
                 }
             }

             if (handle->info.has_bulk_out) {
                 kr = (*interface)->ClearPipeStallBothEnds(interface,
                         handle->bulkOut);
                 if (kr != 0) {
                     ERR("could not clear output pipe; result %x, ignoring....\n", kr);
                 }
             }

             return 0;
         }

 next_interface:
         (*interface)->USBInterfaceClose(interface);
         (*interface)->Release(interface);
     }

     return 0;
 }

 /** Try out the given device and see if there's a match. Returns 0 on
  * success, -1 on failure.
  */
 static int try_device(io_service_t device, usb_handle *handle) {
     kern_return_t kr;
     IOCFPlugInInterface **plugin = NULL;
     IOUSBDeviceInterface500** dev = NULL;
     SInt32 score;
     HRESULT result;
     UInt8 serialIndex;
     UInt32 locationId;

     // Create an intermediate plugin.
     kr = IOCreatePlugInInterfaceForService(device,
             kIOUSBDeviceUserClientTypeID,
             kIOCFPlugInInterfaceID,
             &plugin, &score);

     if ((kr != 0) || (plugin == NULL)) {
         goto error;
     }

     // Now create the device interface.
     result = (*plugin)->QueryInterface(plugin, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID500),
                                        (LPVOID*)&dev);
     if ((result != 0) || (dev == NULL)) {
         ERR("Couldn't create a device interface (%08x)\n", (int) result);
         goto error;
     }

     /*
      * We don't need the intermediate interface after the device interface
      * is created.
      */
     IODestroyPlugInInterface(plugin);

     // So, we have a device, finally. Grab its vitals.

     kr = (*dev)->GetDeviceVendor(dev, &handle->info.dev_vendor);
     if (kr != 0) {
         ERR("GetDeviceVendor");
         goto error;
     }

     kr = (*dev)->GetDeviceProduct(dev, &handle->info.dev_product);
     if (kr != 0) {
         ERR("GetDeviceProduct");
         goto error;
     }

     kr = (*dev)->GetDeviceClass(dev, &handle->info.dev_class);
     if (kr != 0) {
         ERR("GetDeviceClass");
         goto error;
     }

     kr = (*dev)->GetDeviceSubClass(dev, &handle->info.dev_subclass);
     if (kr != 0) {
         ERR("GetDeviceSubClass");
         goto error;
     }

     kr = (*dev)->GetDeviceProtocol(dev, &handle->info.dev_protocol);
     if (kr != 0) {
         ERR("GetDeviceProtocol");
         goto error;
     }

     kr = (*dev)->GetLocationID(dev, &locationId);
     if (kr != 0) {
         ERR("GetLocationId");
         goto error;
     }
     snprintf(handle->info.device_path, sizeof(handle->info.device_path),
              "usb:%" PRIu32 "X", (unsigned int)locationId);

     kr = (*dev)->USBGetSerialNumberStringIndex(dev, &serialIndex);

     if (serialIndex > 0) {
         IOUSBDevRequest req;
         UInt16  buffer[256];

         req.bmRequestType = USBmakebmRequestType(kUSBIn, kUSBStandard, kUSBDevice);
         req.bRequest = kUSBRqGetDescriptor;
         req.wValue = (kUSBStringDesc << 8) | serialIndex;
         //language ID (en-us) for serial number string
         req.wIndex = 0x0409;
         req.pData = buffer;
         req.wLength = sizeof(buffer);
         kr = (*dev)->DeviceRequest(dev, &req);

         if (kr == kIOReturnSuccess && req.wLenDone > 0) {
             int i, count;

             // skip first word, and copy the rest to the serial string, changing shorts to bytes.
             count = (req.wLenDone - 1) / 2;
             for (i = 0; i < count; i++)
               handle->info.serial_number[i] = buffer[i + 1];
             handle->info.serial_number[i] = 0;
         }
     } else {
         // device has no serial number
         handle->info.serial_number[0] = 0;
     }
     handle->info.interface[0] = 0;
     handle->info.writable = 1;

     if (try_interfaces(dev, handle)) {
         goto error;
     }

     (*dev)->Release(dev);
     return 0;

     error:

     if (dev != NULL) {
         (*dev)->Release(dev);
     }

     return -1;
 }


 /** Initializes the USB system. Returns 0 on success, -1 on error. */
 static int init_usb(ifc_match_func callback, std::unique_ptr<usb_handle>* handle) {
     int ret = -1;
     CFMutableDictionaryRef matchingDict;
     kern_return_t result;
     io_iterator_t iterator;
     usb_handle h;

     h.success = 0;
     h.callback = callback;

     /*
      * Create our matching dictionary to find appropriate devices.
      * IOServiceAddMatchingNotification consumes the reference, so we
      * do not need to release it.
      */
     matchingDict = IOServiceMatching(kIOUSBDeviceClassName);

     if (matchingDict == NULL) {
         ERR("Couldn't create USB matching dictionary.\n");
         return -1;
     }

     result = IOServiceGetMatchingServices(
             kIOMasterPortDefault, matchingDict, &iterator);

     if (result != 0) {
         ERR("Could not create iterator.");
         return -1;
     }

     for (;;) {
         if (! IOIteratorIsValid(iterator)) {
             /*
              * Apple documentation advises resetting the iterator if
              * it should become invalid during iteration.
              */
             IOIteratorReset(iterator);
             continue;
         }

         io_service_t device = IOIteratorNext(iterator);

         if (device == 0) {
             break;
         }

         if (try_device(device, &h) != 0) {
             IOObjectRelease(device);
             continue;
         }

         if (h.success) {
             handle->reset(new usb_handle);
             memcpy(handle->get(), &h, sizeof(usb_handle));
             ret = 0;
             break;
         }

         IOObjectRelease(device);
     }

     IOObjectRelease(iterator);

     return ret;
 }


 /*
  * Definitions of this file's public functions.
  */

 UsbTransport* usb_open(ifc_match_func callback, uint32_t timeout_ms) {
     std::unique_ptr<usb_handle> handle;

     if (init_usb(callback, &handle) < 0) {
         /* Something went wrong initializing USB. */
         return nullptr;
     }

     return new OsxUsbTransport(std::move(handle), timeout_ms);
 }

 OsxUsbTransport::~OsxUsbTransport() {
     Close();
 }

 int OsxUsbTransport::Close() {
     /* TODO: Something better here? */
     return 0;
 }

 /*
   TODO: this SHOULD be easy to do with ResetDevice() from IOUSBDeviceInterface.
   However to perform operations that manipulate the state of the device, you must
   claim ownership of the device with USBDeviceOpenSeize(). However, this operation
   always fails with kIOReturnExclusiveAccess.
   It seems that the kext com.apple.driver.usb.AppleUSBHostCompositeDevice
   always loads and claims ownership of the device and refuses to give it up.
 */
 int OsxUsbTransport::Reset() {
     ERR("USB reset is currently unsupported on osx\n");
     return -1;
 }

 ssize_t OsxUsbTransport::Read(void* data, size_t len) {
     IOReturn result;
     UInt32 numBytes = len;

     if (len == 0) {
         return 0;
     }

     if (handle_ == nullptr) {
         return -1;
     }

     if (handle_->interface == nullptr) {
         ERR("usb_read interface was null\n");
         return -1;
     }

     if (handle_->bulkIn == 0) {
         ERR("bulkIn endpoint not assigned\n");
         return -1;
     }

     if (!ms_timeout_) {
         result = (*handle_->interface)
                          ->ReadPipe(handle_->interface, handle_->bulkIn, data, &numBytes);
     } else {
         result = (*handle_->interface)
                          ->ReadPipeTO(handle_->interface, handle_->bulkIn, data, &numBytes,
                                       ms_timeout_, ms_timeout_);
     }

     if (result == 0) {
         return (int) numBytes;
     } else {
         ERR("usb_read failed with status %x\n", result);
     }

     return -1;
 }

 ssize_t OsxUsbTransport::Write(const void* data, size_t len) {
     IOReturn result;

     if (len == 0) {
         return 0;
     }

     if (handle_ == NULL) {
         return -1;
     }

     if (handle_->interface == NULL) {
         ERR("usb_write interface was null\n");
         return -1;
     }

     if (handle_->bulkOut == 0) {
         ERR("bulkOut endpoint not assigned\n");
         return -1;
     }

 #if 0
     result = (*handle_->interface)->WritePipe(
             handle_->interface, handle_->bulkOut, (void *)data, len);
 #else
     /* Attempt to work around crashes in the USB driver that may be caused
      * by trying to write too much data at once.  The kernel IOCopyMapper
      * panics if a single iovmAlloc needs more than half of its mapper pages.
      */
     const int maxLenToSend = 1048576; // 1 MiB
     int lenRemaining = len;
     result = 0;
     while (lenRemaining > 0) {
         int lenToSend = lenRemaining > maxLenToSend
             ? maxLenToSend : lenRemaining;

         if (!ms_timeout_) {  // blocking
             result = (*handle_->interface)
                              ->WritePipe(handle_->interface, handle_->bulkOut, (void*)data,
                                          lenToSend);
         } else {
             result = (*handle_->interface)
                              ->WritePipeTO(handle_->interface, handle_->bulkOut, (void*)data,
                                            lenToSend, ms_timeout_, ms_timeout_);
         }

         if (result != 0) break;

         lenRemaining -= lenToSend;
         data = (const char*)data + lenToSend;
     }
 #endif

     #if 0
     if ((result == 0) && (handle_->zero_mask)) {
         /* we need 0-markers and our transfer */
         if(!(len & handle_->zero_mask)) {
             result = (*handle_->interface)->WritePipe(
                     handle_->interface, handle_->bulkOut, (void *)data, 0);
         }
     }
     #endif

     if (result != 0) {
         ERR("usb_write failed with status %x\n", result);
         return -1;
     }

     return len;
 }
	/*
	* Copyright (C) 2008 The Android Open Source Project
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
	* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
	* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
	* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
	* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
	* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*/

	#include <inttypes.h>
	#include <stdio.h>
	#include <CoreFoundation/CoreFoundation.h>
	#include <IOKit/IOKitLib.h>
	#include <IOKit/IOCFPlugIn.h>
	#include <IOKit/usb/IOUSBLib.h>
	#include <IOKit/IOMessage.h>
	#include <mach/mach_port.h>

	#include <memory>

	#include "usb.h"


	/*
	* Internal helper functions and associated definitions.
	*/

	#if TRACE_USB
	#define WARN(x...) fprintf(stderr, x)
	#else
	#define WARN(x...)
	#endif

	#define ERR(x...) fprintf(stderr, "ERROR: " x)

	/** An open usb device */
	struct usb_handle
	{
	int success;
	ifc_match_func callback;
	usb_ifc_info info;

	UInt8 bulkIn;
	UInt8 bulkOut;
	IOUSBInterfaceInterface500** interface;
	unsigned int zero_mask;
	};

	class OsxUsbTransport : public UsbTransport {
	public:
	// A timeout of 0 is blocking
	OsxUsbTransport(std::unique_ptr<usb_handle> handle, uint32_t ms_timeout = 0)
	: handle_(std::move(handle)), ms_timeout_(ms_timeout) {}
	~OsxUsbTransport() override;

	ssize_t Read(void* data, size_t len) override;
	ssize_t Write(const void* data, size_t len) override;
	int Close() override;
	int Reset() override;

	private:
	std::unique_ptr<usb_handle> handle_;
	const uint32_t ms_timeout_;

	DISALLOW_COPY_AND_ASSIGN(OsxUsbTransport);
	};

	/** Try out all the interfaces and see if there's a match. Returns 0 on
	* success, -1 on failure. */
	static int try_interfaces(IOUSBDeviceInterface500** dev, usb_handle* handle) {
	IOReturn kr;
	IOUSBFindInterfaceRequest request;
	io_iterator_t iterator;
	io_service_t usbInterface;
	IOCFPlugInInterface **plugInInterface;
	IOUSBInterfaceInterface500** interface = NULL;
	HRESULT result;
	SInt32 score;
	UInt8 interfaceNumEndpoints;

	request.bInterfaceClass = 0xff;
	request.bInterfaceSubClass = 0x42;
	request.bInterfaceProtocol = 0x03;
	request.bAlternateSetting = kIOUSBFindInterfaceDontCare;

	// Get an iterator for the interfaces on the device
	kr = (*dev)->CreateInterfaceIterator(dev, &request, &iterator);

	if (kr != 0) {
	WARN("Couldn't create a device interface iterator: (%08x)\n", kr);
	return -1;
	}

	while ((usbInterface = IOIteratorNext(iterator))) {
	// Create an intermediate plugin
	kr = IOCreatePlugInInterfaceForService(
	usbInterface,
	kIOUSBInterfaceUserClientTypeID,
	kIOCFPlugInInterfaceID,
	&plugInInterface,
	&score);

	// No longer need the usbInterface object now that we have the plugin
	(void) IOObjectRelease(usbInterface);

	if ((kr != 0) \|\| (!plugInInterface)) {
	WARN("Unable to create plugin (%08x)\n", kr);
	continue;
	}

	// Now create the interface interface for the interface
	result = (*plugInInterface)
	->QueryInterface(plugInInterface,
	CFUUIDGetUUIDBytes(kIOUSBInterfaceInterfaceID500),
	(LPVOID*)&interface);

	// No longer need the intermediate plugin
	(*plugInInterface)->Release(plugInInterface);

	if (result \|\| !interface) {
	ERR("Couldn't create interface interface: (%08x)\n",
	(unsigned int) result);
	// continue so we can try the next interface
	continue;
	}

	/*
	* Now open the interface. This will cause the pipes
	* associated with the endpoints in the interface descriptor
	* to be instantiated.
	*/

	/*
	* TODO: Earlier comments here indicated that it was a bad
	* idea to just open any interface, because opening "mass
	* storage endpoints" is bad. However, the only way to find
	* out if an interface does bulk in or out is to open it, and
	* the framework in this application wants to be told about
	* bulk in / out before deciding whether it actually wants to
	* use the interface. Maybe something needs to be done about
	* this situation.
	*/

	kr = (*interface)->USBInterfaceOpen(interface);

	if (kr != 0) {
	WARN("Could not open interface: (%08x)\n", kr);
	(void) (*interface)->Release(interface);
	// continue so we can try the next interface
	continue;
	}

	// Get the number of endpoints associated with this interface.
	kr = (*interface)->GetNumEndpoints(interface, &interfaceNumEndpoints);

	if (kr != 0) {
	ERR("Unable to get number of endpoints: (%08x)\n", kr);
	goto next_interface;
	}

	// Get interface class, subclass and protocol
	if ((*interface)->GetInterfaceClass(interface, &handle->info.ifc_class) != 0 \|\|
	(*interface)->GetInterfaceSubClass(interface, &handle->info.ifc_subclass) != 0 \|\|
	(*interface)->GetInterfaceProtocol(interface, &handle->info.ifc_protocol) != 0)
	{
	ERR("Unable to get interface class, subclass and protocol\n");
	goto next_interface;
	}

	handle->info.has_bulk_in = 0;
	handle->info.has_bulk_out = 0;

	// Iterate over the endpoints for this interface and see if there
	// are any that do bulk in/out.
	for (UInt8 endpoint = 1; endpoint <= interfaceNumEndpoints; endpoint++) {
	UInt8 transferType;
	UInt16 maxPacketSize;
	UInt8 interval;
	UInt8 number;
	UInt8 direction;

	kr = (*interface)->GetPipeProperties(interface, endpoint,
	&direction,
	&number, &transferType, &maxPacketSize, &interval);

	if (kr == 0) {
	if (transferType != kUSBBulk) {
	continue;
	}

	if (direction == kUSBIn) {
	handle->info.has_bulk_in = 1;
	handle->bulkIn = endpoint;
	} else if (direction == kUSBOut) {
	handle->info.has_bulk_out = 1;
	handle->bulkOut = endpoint;
	}

	if (handle->info.ifc_protocol == 0x01) {
	handle->zero_mask = maxPacketSize - 1;
	}
	} else {
	ERR("could not get pipe properties for endpoint %u (%08x)\n", endpoint, kr);
	}

	if (handle->info.has_bulk_in && handle->info.has_bulk_out) {
	break;
	}
	}

	if (handle->callback(&handle->info) == 0) {
	handle->interface = interface;
	handle->success = 1;

	/*
	* Clear both the endpoints, because it has been observed
	* that the Mac may otherwise (incorrectly) start out with
	* them in bad state.
	*/

	if (handle->info.has_bulk_in) {
	kr = (*interface)->ClearPipeStallBothEnds(interface,
	handle->bulkIn);
	if (kr != 0) {
	ERR("could not clear input pipe; result %x, ignoring...\n", kr);
	}
	}

	if (handle->info.has_bulk_out) {
	kr = (*interface)->ClearPipeStallBothEnds(interface,
	handle->bulkOut);
	if (kr != 0) {
	ERR("could not clear output pipe; result %x, ignoring....\n", kr);
	}
	}

	return 0;
	}

	next_interface:
	(*interface)->USBInterfaceClose(interface);
	(*interface)->Release(interface);
	}

	return 0;
	}

	/** Try out the given device and see if there's a match. Returns 0 on
	* success, -1 on failure.
	*/
	static int try_device(io_service_t device, usb_handle *handle) {
	kern_return_t kr;
	IOCFPlugInInterface **plugin = NULL;
	IOUSBDeviceInterface500** dev = NULL;
	SInt32 score;
	HRESULT result;
	UInt8 serialIndex;
	UInt32 locationId;

	// Create an intermediate plugin.
	kr = IOCreatePlugInInterfaceForService(device,
	kIOUSBDeviceUserClientTypeID,
	kIOCFPlugInInterfaceID,
	&plugin, &score);

	if ((kr != 0) \|\| (plugin == NULL)) {
	goto error;
	}

	// Now create the device interface.
	result = (*plugin)->QueryInterface(plugin, CFUUIDGetUUIDBytes(kIOUSBDeviceInterfaceID500),
	(LPVOID*)&dev);
	if ((result != 0) \|\| (dev == NULL)) {
	ERR("Couldn't create a device interface (%08x)\n", (int) result);
	goto error;
	}

	/*
	* We don't need the intermediate interface after the device interface
	* is created.
	*/
	IODestroyPlugInInterface(plugin);

	// So, we have a device, finally. Grab its vitals.

	kr = (*dev)->GetDeviceVendor(dev, &handle->info.dev_vendor);
	if (kr != 0) {
	ERR("GetDeviceVendor");
	goto error;
	}

	kr = (*dev)->GetDeviceProduct(dev, &handle->info.dev_product);
	if (kr != 0) {
	ERR("GetDeviceProduct");
	goto error;
	}

	kr = (*dev)->GetDeviceClass(dev, &handle->info.dev_class);
	if (kr != 0) {
	ERR("GetDeviceClass");
	goto error;
	}

	kr = (*dev)->GetDeviceSubClass(dev, &handle->info.dev_subclass);
	if (kr != 0) {
	ERR("GetDeviceSubClass");
	goto error;
	}

	kr = (*dev)->GetDeviceProtocol(dev, &handle->info.dev_protocol);
	if (kr != 0) {
	ERR("GetDeviceProtocol");
	goto error;
	}

	kr = (*dev)->GetLocationID(dev, &locationId);
	if (kr != 0) {
	ERR("GetLocationId");
	goto error;
	}
	snprintf(handle->info.device_path, sizeof(handle->info.device_path),
	"usb:%" PRIu32 "X", (unsigned int)locationId);

	kr = (*dev)->USBGetSerialNumberStringIndex(dev, &serialIndex);

	if (serialIndex > 0) {
	IOUSBDevRequest req;
	UInt16 buffer[256];

	req.bmRequestType = USBmakebmRequestType(kUSBIn, kUSBStandard, kUSBDevice);
	req.bRequest = kUSBRqGetDescriptor;
	req.wValue = (kUSBStringDesc << 8) \| serialIndex;
	//language ID (en-us) for serial number string
	req.wIndex = 0x0409;
	req.pData = buffer;
	req.wLength = sizeof(buffer);
	kr = (*dev)->DeviceRequest(dev, &req);

	if (kr == kIOReturnSuccess && req.wLenDone > 0) {
	int i, count;

	// skip first word, and copy the rest to the serial string, changing shorts to bytes.
	count = (req.wLenDone - 1) / 2;
	for (i = 0; i < count; i++)
	handle->info.serial_number[i] = buffer[i + 1];
	handle->info.serial_number[i] = 0;
	}
	} else {
	// device has no serial number
	handle->info.serial_number[0] = 0;
	}
	handle->info.interface[0] = 0;
	handle->info.writable = 1;

	if (try_interfaces(dev, handle)) {
	goto error;
	}

	(*dev)->Release(dev);
	return 0;

	error:

	if (dev != NULL) {
	(*dev)->Release(dev);
	}

	return -1;
	}


	/** Initializes the USB system. Returns 0 on success, -1 on error. */
	static int init_usb(ifc_match_func callback, std::unique_ptr<usb_handle>* handle) {
	int ret = -1;
	CFMutableDictionaryRef matchingDict;
	kern_return_t result;
	io_iterator_t iterator;
	usb_handle h;

	h.success = 0;
	h.callback = callback;

	/*
	* Create our matching dictionary to find appropriate devices.
	* IOServiceAddMatchingNotification consumes the reference, so we
	* do not need to release it.
	*/
	matchingDict = IOServiceMatching(kIOUSBDeviceClassName);

	if (matchingDict == NULL) {
	ERR("Couldn't create USB matching dictionary.\n");
	return -1;
	}

	result = IOServiceGetMatchingServices(
	kIOMasterPortDefault, matchingDict, &iterator);

	if (result != 0) {
	ERR("Could not create iterator.");
	return -1;
	}

	for (;;) {
	if (! IOIteratorIsValid(iterator)) {
	/*
	* Apple documentation advises resetting the iterator if
	* it should become invalid during iteration.
	*/
	IOIteratorReset(iterator);
	continue;
	}

	io_service_t device = IOIteratorNext(iterator);

	if (device == 0) {
	break;
	}

	if (try_device(device, &h) != 0) {
	IOObjectRelease(device);
	continue;
	}

	if (h.success) {
	handle->reset(new usb_handle);
	memcpy(handle->get(), &h, sizeof(usb_handle));
	ret = 0;
	break;
	}

	IOObjectRelease(device);
	}

	IOObjectRelease(iterator);

	return ret;
	}



	/*
	* Definitions of this file's public functions.
	*/

	UsbTransport* usb_open(ifc_match_func callback, uint32_t timeout_ms) {
	std::unique_ptr<usb_handle> handle;

	if (init_usb(callback, &handle) < 0) {
	/* Something went wrong initializing USB. */
	return nullptr;
	}

	return new OsxUsbTransport(std::move(handle), timeout_ms);
	}

	OsxUsbTransport::~OsxUsbTransport() {
	Close();
	}

	int OsxUsbTransport::Close() {
	/* TODO: Something better here? */
	return 0;
	}

	/*
	TODO: this SHOULD be easy to do with ResetDevice() from IOUSBDeviceInterface.
	However to perform operations that manipulate the state of the device, you must
	claim ownership of the device with USBDeviceOpenSeize(). However, this operation
	always fails with kIOReturnExclusiveAccess.
	It seems that the kext com.apple.driver.usb.AppleUSBHostCompositeDevice
	always loads and claims ownership of the device and refuses to give it up.
	*/
	int OsxUsbTransport::Reset() {
	ERR("USB reset is currently unsupported on osx\n");
	return -1;
	}

	ssize_t OsxUsbTransport::Read(void* data, size_t len) {
	IOReturn result;
	UInt32 numBytes = len;

	if (len == 0) {
	return 0;
	}

	if (handle_ == nullptr) {
	return -1;
	}

	if (handle_->interface == nullptr) {
	ERR("usb_read interface was null\n");
	return -1;
	}

	if (handle_->bulkIn == 0) {
	ERR("bulkIn endpoint not assigned\n");
	return -1;
	}

	if (!ms_timeout_) {
	result = (*handle_->interface)
	->ReadPipe(handle_->interface, handle_->bulkIn, data, &numBytes);
	} else {
	result = (*handle_->interface)
	->ReadPipeTO(handle_->interface, handle_->bulkIn, data, &numBytes,
	ms_timeout_, ms_timeout_);
	}

	if (result == 0) {
	return (int) numBytes;
	} else {
	ERR("usb_read failed with status %x\n", result);
	}

	return -1;
	}

	ssize_t OsxUsbTransport::Write(const void* data, size_t len) {
	IOReturn result;

	if (len == 0) {
	return 0;
	}

	if (handle_ == NULL) {
	return -1;
	}

	if (handle_->interface == NULL) {
	ERR("usb_write interface was null\n");
	return -1;
	}

	if (handle_->bulkOut == 0) {
	ERR("bulkOut endpoint not assigned\n");
	return -1;
	}

	#if 0
	result = (*handle_->interface)->WritePipe(
	handle_->interface, handle_->bulkOut, (void *)data, len);
	#else
	/* Attempt to work around crashes in the USB driver that may be caused
	* by trying to write too much data at once. The kernel IOCopyMapper
	* panics if a single iovmAlloc needs more than half of its mapper pages.
	*/
	const int maxLenToSend = 1048576; // 1 MiB
	int lenRemaining = len;
	result = 0;
	while (lenRemaining > 0) {
	int lenToSend = lenRemaining > maxLenToSend
	? maxLenToSend : lenRemaining;

	if (!ms_timeout_) { // blocking
	result = (*handle_->interface)
	->WritePipe(handle_->interface, handle_->bulkOut, (void*)data,
	lenToSend);
	} else {
	result = (*handle_->interface)
	->WritePipeTO(handle_->interface, handle_->bulkOut, (void*)data,
	lenToSend, ms_timeout_, ms_timeout_);
	}

	if (result != 0) break;

	lenRemaining -= lenToSend;
	data = (const char*)data + lenToSend;
	}
	#endif

	#if 0
	if ((result == 0) && (handle_->zero_mask)) {
	/* we need 0-markers and our transfer */
	if(!(len & handle_->zero_mask)) {
	result = (*handle_->interface)->WritePipe(
	handle_->interface, handle_->bulkOut, (void *)data, 0);
	}
	}
	#endif

	if (result != 0) {
	ERR("usb_write failed with status %x\n", result);
	return -1;
	}

	return len;
	}