android-8.1.0_r81/s

/*
 * windows backend for libusb 1.0
 * Copyright © 2009-2012 Pete Batard <pete@akeo.ie>
 * With contributions from Michael Plante, Orin Eman et al.
 * Parts of this code adapted from libusb-win32-v1 by Stephan Meyer
 * HID Reports IOCTLs inspired from HIDAPI by Alan Ott, Signal 11 Software
 * Hash table functions adapted from glibc, by Ulrich Drepper et al.
 * Major code testing contribution by Xiaofan Chen
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <config.h>

#if !defined(USE_USBDK)

#include <windows.h>
#include <setupapi.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <process.h>
#include <stdio.h>
#include <inttypes.h>
#include <objbase.h>
#include <winioctl.h>

#include "libusbi.h"
#include "poll_windows.h"
#include "windows_winusb.h"

#define HANDLE_VALID(h) (((h) != 0) && ((h) != INVALID_HANDLE_VALUE))

// The 2 macros below are used in conjunction with safe loops.
#define LOOP_CHECK(fcall)			\
	{					\
		r = fcall;			\
		if (r != LIBUSB_SUCCESS)	\
			continue;		\
	}
#define LOOP_BREAK(err)				\
	{					\
		r = err;			\
		continue;			\
	}

// WinUSB-like API prototypes
static int winusbx_init(int sub_api, struct libusb_context *ctx);
static int winusbx_exit(int sub_api);
static int winusbx_open(int sub_api, struct libusb_device_handle *dev_handle);
static void winusbx_close(int sub_api, struct libusb_device_handle *dev_handle);
static int winusbx_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface);
static int winusbx_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
static int winusbx_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
static int winusbx_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
static int winusbx_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
static int winusbx_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
static int winusbx_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
static int winusbx_abort_control(int sub_api, struct usbi_transfer *itransfer);
static int winusbx_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
static int winusbx_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
// HID API prototypes
static int hid_init(int sub_api, struct libusb_context *ctx);
static int hid_exit(int sub_api);
static int hid_open(int sub_api, struct libusb_device_handle *dev_handle);
static void hid_close(int sub_api, struct libusb_device_handle *dev_handle);
static int hid_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
static int hid_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
static int hid_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
static int hid_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
static int hid_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
static int hid_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
static int hid_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
static int hid_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
static int hid_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
// Composite API prototypes
static int composite_init(int sub_api, struct libusb_context *ctx);
static int composite_exit(int sub_api);
static int composite_open(int sub_api, struct libusb_device_handle *dev_handle);
static void composite_close(int sub_api, struct libusb_device_handle *dev_handle);
static int composite_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
static int composite_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
static int composite_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
static int composite_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
static int composite_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
static int composite_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer);
static int composite_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
static int composite_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
static int composite_abort_control(int sub_api, struct usbi_transfer *itransfer);
static int composite_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
static int composite_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);


// Global variables
int windows_version = WINDOWS_UNDEFINED;
static char windows_version_str[128] = "Windows Undefined";
// Concurrency
static int concurrent_usage = -1;
static usbi_mutex_t autoclaim_lock;
// API globals
#define CHECK_WINUSBX_AVAILABLE(sub_api)		\
	do {						\
		if (sub_api == SUB_API_NOTSET)		\
			sub_api = priv->sub_api;	\
		if (!WinUSBX[sub_api].initialized) 	\
			return LIBUSB_ERROR_ACCESS;	\
	} while(0)

static HMODULE WinUSBX_handle = NULL;
static struct winusb_interface WinUSBX[SUB_API_MAX];
static const char *sub_api_name[SUB_API_MAX] = WINUSBX_DRV_NAMES;

static bool api_hid_available = false;
#define CHECK_HID_AVAILABLE				\
	do {						\
		if (!api_hid_available)			\
			return LIBUSB_ERROR_ACCESS;	\
	} while (0)

static inline BOOLEAN guid_eq(const GUID *guid1, const GUID *guid2)
{
	if ((guid1 != NULL) && (guid2 != NULL))
		return (memcmp(guid1, guid2, sizeof(GUID)) == 0);

	return false;
}

#if defined(ENABLE_LOGGING)
static char *guid_to_string(const GUID *guid)
{
	static char guid_string[MAX_GUID_STRING_LENGTH];

	if (guid == NULL)
		return NULL;

	sprintf(guid_string, "{%08X-%04X-%04X-%02X%02X-%02X%02X%02X%02X%02X%02X}",
		(unsigned int)guid->Data1, guid->Data2, guid->Data3,
		guid->Data4[0], guid->Data4[1], guid->Data4[2], guid->Data4[3],
		guid->Data4[4], guid->Data4[5], guid->Data4[6], guid->Data4[7]);

	return guid_string;
}
#endif

/*
 * Sanitize Microsoft's paths: convert to uppercase, add prefix and fix backslashes.
 * Return an allocated sanitized string or NULL on error.
 */
static char *sanitize_path(const char *path)
{
	const char root_prefix[] = "\\\\.\\";
	size_t j, size, root_size;
	char *ret_path = NULL;
	size_t add_root = 0;

	if (path == NULL)
		return NULL;

	size = safe_strlen(path) + 1;
	root_size = sizeof(root_prefix) - 1;

	// Microsoft indiscriminately uses '\\?\', '\\.\', '##?#" or "##.#" for root prefixes.
	if (!((size > 3) && (((path[0] == '\\') && (path[1] == '\\') && (path[3] == '\\'))
			|| ((path[0] == '#') && (path[1] == '#') && (path[3] == '#'))))) {
		add_root = root_size;
		size += add_root;
	}

	ret_path = calloc(1, size);
	if (ret_path == NULL)
		return NULL;

	safe_strcpy(&ret_path[add_root], size-add_root, path);

	// Ensure consistency with root prefix
	for (j = 0; j < root_size; j++)
		ret_path[j] = root_prefix[j];

	// Same goes for '\' and '#' after the root prefix. Ensure '#' is used
	for (j = root_size; j < size; j++) {
		ret_path[j] = (char)toupper((int)ret_path[j]); // Fix case too
		if (ret_path[j] == '\\')
			ret_path[j] = '#';
	}

	return ret_path;
}

/*
 * Cfgmgr32, OLE32 and SetupAPI DLL functions
 */
static int init_dlls(void)
{
	DLL_GET_HANDLE(Cfgmgr32);
	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Parent, TRUE);
	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Child, TRUE);
	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Sibling, TRUE);
	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Device_IDA, TRUE);

	// Prefixed to avoid conflict with header files
	DLL_GET_HANDLE(AdvAPI32);
	DLL_LOAD_FUNC_PREFIXED(AdvAPI32, p, RegQueryValueExW, TRUE);
	DLL_LOAD_FUNC_PREFIXED(AdvAPI32, p, RegCloseKey, TRUE);

	DLL_GET_HANDLE(Kernel32);
	DLL_LOAD_FUNC_PREFIXED(Kernel32, p, IsWow64Process, FALSE);

	DLL_GET_HANDLE(OLE32);
	DLL_LOAD_FUNC_PREFIXED(OLE32, p, CLSIDFromString, TRUE);

	DLL_GET_HANDLE(SetupAPI);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiGetClassDevsA, TRUE);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiEnumDeviceInfo, TRUE);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiEnumDeviceInterfaces, TRUE);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiGetDeviceInterfaceDetailA, TRUE);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiDestroyDeviceInfoList, TRUE);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiOpenDevRegKey, TRUE);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiGetDeviceRegistryPropertyA, TRUE);
	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiOpenDeviceInterfaceRegKey, TRUE);

	return LIBUSB_SUCCESS;
}

static void exit_dlls(void)
{
	DLL_FREE_HANDLE(Cfgmgr32);
	DLL_FREE_HANDLE(AdvAPI32);
	DLL_FREE_HANDLE(Kernel32);
	DLL_FREE_HANDLE(OLE32);
	DLL_FREE_HANDLE(SetupAPI);
}

/*
 * enumerate interfaces for the whole USB class
 *
 * Parameters:
 * dev_info: a pointer to a dev_info list
 * dev_info_data: a pointer to an SP_DEVINFO_DATA to be filled (or NULL if not needed)
 * usb_class: the generic USB class for which to retrieve interface details
 * index: zero based index of the interface in the device info list
 *
 * Note: it is the responsibility of the caller to free the DEVICE_INTERFACE_DETAIL_DATA
 * structure returned and call this function repeatedly using the same guid (with an
 * incremented index starting at zero) until all interfaces have been returned.
 */
static bool get_devinfo_data(struct libusb_context *ctx,
	HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const char *usb_class, unsigned _index)
{
	if (_index <= 0) {
		*dev_info = pSetupDiGetClassDevsA(NULL, usb_class, NULL, DIGCF_PRESENT|DIGCF_ALLCLASSES);
		if (*dev_info == INVALID_HANDLE_VALUE)
			return false;
	}

	dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
	if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
		if (GetLastError() != ERROR_NO_MORE_ITEMS)
			usbi_err(ctx, "Could not obtain device info data for index %u: %s",
				_index, windows_error_str(0));

		pSetupDiDestroyDeviceInfoList(*dev_info);
		*dev_info = INVALID_HANDLE_VALUE;
		return false;
	}
	return true;
}

/*
 * enumerate interfaces for a specific GUID
 *
 * Parameters:
 * dev_info: a pointer to a dev_info list
 * dev_info_data: a pointer to an SP_DEVINFO_DATA to be filled (or NULL if not needed)
 * guid: the GUID for which to retrieve interface details
 * index: zero based index of the interface in the device info list
 *
 * Note: it is the responsibility of the caller to free the DEVICE_INTERFACE_DETAIL_DATA
 * structure returned and call this function repeatedly using the same guid (with an
 * incremented index starting at zero) until all interfaces have been returned.
 */
static SP_DEVICE_INTERFACE_DETAIL_DATA_A *get_interface_details(struct libusb_context *ctx,
	HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const GUID *guid, unsigned _index)
{
	SP_DEVICE_INTERFACE_DATA dev_interface_data;
	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
	DWORD size;

	if (_index <= 0)
		*dev_info = pSetupDiGetClassDevsA(guid, NULL, NULL, DIGCF_PRESENT|DIGCF_DEVICEINTERFACE);

	if (dev_info_data != NULL) {
		dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
		if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
			if (GetLastError() != ERROR_NO_MORE_ITEMS)
				usbi_err(ctx, "Could not obtain device info data for index %u: %s",
					_index, windows_error_str(0));

			pSetupDiDestroyDeviceInfoList(*dev_info);
			*dev_info = INVALID_HANDLE_VALUE;
			return NULL;
		}
	}

	dev_interface_data.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
	if (!pSetupDiEnumDeviceInterfaces(*dev_info, NULL, guid, _index, &dev_interface_data)) {
		if (GetLastError() != ERROR_NO_MORE_ITEMS)
			usbi_err(ctx, "Could not obtain interface data for index %u: %s",
				_index, windows_error_str(0));

		pSetupDiDestroyDeviceInfoList(*dev_info);
		*dev_info = INVALID_HANDLE_VALUE;
		return NULL;
	}

	// Read interface data (dummy + actual) to access the device path
	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, NULL, 0, &size, NULL)) {
		// The dummy call should fail with ERROR_INSUFFICIENT_BUFFER
		if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
			usbi_err(ctx, "could not access interface data (dummy) for index %u: %s",
				_index, windows_error_str(0));
			goto err_exit;
		}
	} else {
		usbi_err(ctx, "program assertion failed - http://msdn.microsoft.com/en-us/library/ms792901.aspx is wrong.");
		goto err_exit;
	}

	dev_interface_details = calloc(1, size);
	if (dev_interface_details == NULL) {
		usbi_err(ctx, "could not allocate interface data for index %u.", _index);
		goto err_exit;
	}

	dev_interface_details->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA_A);
	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data,
		dev_interface_details, size, &size, NULL)) {
		usbi_err(ctx, "could not access interface data (actual) for index %u: %s",
			_index, windows_error_str(0));
	}

	return dev_interface_details;

err_exit:
	pSetupDiDestroyDeviceInfoList(*dev_info);
	*dev_info = INVALID_HANDLE_VALUE;
	return NULL;
}

/* For libusb0 filter */
static SP_DEVICE_INTERFACE_DETAIL_DATA_A *get_interface_details_filter(struct libusb_context *ctx,
	HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const GUID *guid, unsigned _index, char *filter_path)
{
	SP_DEVICE_INTERFACE_DATA dev_interface_data;
	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
	DWORD size;

	if (_index <= 0)
		*dev_info = pSetupDiGetClassDevsA(guid, NULL, NULL, DIGCF_PRESENT|DIGCF_DEVICEINTERFACE);

	if (dev_info_data != NULL) {
		dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
		if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
			if (GetLastError() != ERROR_NO_MORE_ITEMS)
				usbi_err(ctx, "Could not obtain device info data for index %u: %s",
					_index, windows_error_str(0));

			pSetupDiDestroyDeviceInfoList(*dev_info);
			*dev_info = INVALID_HANDLE_VALUE;
			return NULL;
		}
	}

	dev_interface_data.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
	if (!pSetupDiEnumDeviceInterfaces(*dev_info, NULL, guid, _index, &dev_interface_data)) {
		if (GetLastError() != ERROR_NO_MORE_ITEMS)
			usbi_err(ctx, "Could not obtain interface data for index %u: %s",
				_index, windows_error_str(0));

		pSetupDiDestroyDeviceInfoList(*dev_info);
		*dev_info = INVALID_HANDLE_VALUE;
		return NULL;
	}

	// Read interface data (dummy + actual) to access the device path
	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, NULL, 0, &size, NULL)) {
		// The dummy call should fail with ERROR_INSUFFICIENT_BUFFER
		if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
			usbi_err(ctx, "could not access interface data (dummy) for index %u: %s",
				_index, windows_error_str(0));
			goto err_exit;
		}
	} else {
		usbi_err(ctx, "program assertion failed - http://msdn.microsoft.com/en-us/library/ms792901.aspx is wrong.");
		goto err_exit;
	}

	dev_interface_details = calloc(1, size);
	if (dev_interface_details == NULL) {
		usbi_err(ctx, "could not allocate interface data for index %u.", _index);
		goto err_exit;
	}

	dev_interface_details->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA_A);
	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, dev_interface_details, size, &size, NULL))
		usbi_err(ctx, "could not access interface data (actual) for index %u: %s",
			_index, windows_error_str(0));

	// [trobinso] lookup the libusb0 symbolic index.
	if (dev_interface_details) {
		HKEY hkey_device_interface = pSetupDiOpenDeviceInterfaceRegKey(*dev_info, &dev_interface_data, 0, KEY_READ);
		if (hkey_device_interface != INVALID_HANDLE_VALUE) {
			DWORD libusb0_symboliclink_index = 0;
			DWORD value_length = sizeof(DWORD);
			DWORD value_type = 0;
			LONG status;

			status = pRegQueryValueExW(hkey_device_interface, L"LUsb0", NULL, &value_type,
				(LPBYTE)&libusb0_symboliclink_index, &value_length);
			if (status == ERROR_SUCCESS) {
				if (libusb0_symboliclink_index < 256) {
					// libusb0.sys is connected to this device instance.
					// If the the device interface guid is {F9F3FF14-AE21-48A0-8A25-8011A7A931D9} then it's a filter.
					safe_sprintf(filter_path, sizeof("\\\\.\\libusb0-0000"), "\\\\.\\libusb0-%04u", (unsigned int)libusb0_symboliclink_index);
					usbi_dbg("assigned libusb0 symbolic link %s", filter_path);
				} else {
					// libusb0.sys was connected to this device instance at one time; but not anymore.
				}
			}
			pRegCloseKey(hkey_device_interface);
		}
	}

	return dev_interface_details;

err_exit:
	pSetupDiDestroyDeviceInfoList(*dev_info);
	*dev_info = INVALID_HANDLE_VALUE;
	return NULL;
}

/*
 * Returns the session ID of a device's nth level ancestor
 * If there's no device at the nth level, return 0
 */
static unsigned long get_ancestor_session_id(DWORD devinst, unsigned level)
{
	DWORD parent_devinst;
	unsigned long session_id = 0;
	char *sanitized_path = NULL;
	char path[MAX_PATH_LENGTH];
	unsigned i;

	if (level < 1)
		return 0;

	for (i = 0; i < level; i++) {
		if (CM_Get_Parent(&parent_devinst, devinst, 0) != CR_SUCCESS)
			return 0;
		devinst = parent_devinst;
	}

	if (CM_Get_Device_IDA(devinst, path, MAX_PATH_LENGTH, 0) != CR_SUCCESS)
		return 0;

	// TODO: (post hotplug): try without sanitizing
	sanitized_path = sanitize_path(path);
	if (sanitized_path == NULL)
		return 0;

	session_id = htab_hash(sanitized_path);
	safe_free(sanitized_path);
	return session_id;
}

/*
 * Determine which interface the given endpoint address belongs to
 */
static int get_interface_by_endpoint(struct libusb_config_descriptor *conf_desc, uint8_t ep)
{
	const struct libusb_interface *intf;
	const struct libusb_interface_descriptor *intf_desc;
	int i, j, k;

	for (i = 0; i < conf_desc->bNumInterfaces; i++) {
		intf = &conf_desc->interface[i];
		for (j = 0; j < intf->num_altsetting; j++) {
			intf_desc = &intf->altsetting[j];
			for (k = 0; k < intf_desc->bNumEndpoints; k++) {
				if (intf_desc->endpoint[k].bEndpointAddress == ep) {
					usbi_dbg("found endpoint %02X on interface %d", intf_desc->bInterfaceNumber, i);
					return intf_desc->bInterfaceNumber;
				}
			}
		}
	}

	usbi_dbg("endpoint %02X not found on any interface", ep);
	return LIBUSB_ERROR_NOT_FOUND;
}

/*
 * Populate the endpoints addresses of the device_priv interface helper structs
 */
static int windows_assign_endpoints(struct libusb_device_handle *dev_handle, int iface, int altsetting)
{
	int i, r;
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	struct libusb_config_descriptor *conf_desc;
	const struct libusb_interface_descriptor *if_desc;
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);

	r = libusb_get_active_config_descriptor(dev_handle->dev, &conf_desc);
	if (r != LIBUSB_SUCCESS) {
		usbi_warn(ctx, "could not read config descriptor: error %d", r);
		return r;
	}

	if_desc = &conf_desc->interface[iface].altsetting[altsetting];
	safe_free(priv->usb_interface[iface].endpoint);

	if (if_desc->bNumEndpoints == 0) {
		usbi_dbg("no endpoints found for interface %d", iface);
		libusb_free_config_descriptor(conf_desc);
		return LIBUSB_SUCCESS;
	}

	priv->usb_interface[iface].endpoint = malloc(if_desc->bNumEndpoints);
	if (priv->usb_interface[iface].endpoint == NULL) {
		libusb_free_config_descriptor(conf_desc);
		return LIBUSB_ERROR_NO_MEM;
	}

	priv->usb_interface[iface].nb_endpoints = if_desc->bNumEndpoints;
	for (i = 0; i < if_desc->bNumEndpoints; i++) {
		priv->usb_interface[iface].endpoint[i] = if_desc->endpoint[i].bEndpointAddress;
		usbi_dbg("(re)assigned endpoint %02X to interface %d", priv->usb_interface[iface].endpoint[i], iface);
	}
	libusb_free_config_descriptor(conf_desc);

	// Extra init may be required to configure endpoints
	return priv->apib->configure_endpoints(SUB_API_NOTSET, dev_handle, iface);
}

// Lookup for a match in the list of API driver names
// return -1 if not found, driver match number otherwise
static int get_sub_api(char *driver, int api)
{
	int i;
	const char sep_str[2] = {LIST_SEPARATOR, 0};
	char *tok, *tmp_str;
	size_t len = safe_strlen(driver);

	if (len == 0)
		return SUB_API_NOTSET;

	tmp_str = _strdup(driver);
	if (tmp_str == NULL)
		return SUB_API_NOTSET;

	tok = strtok(tmp_str, sep_str);
	while (tok != NULL) {
		for (i = 0; i < usb_api_backend[api].nb_driver_names; i++) {
			if (safe_stricmp(tok, usb_api_backend[api].driver_name_list[i]) == 0) {
				free(tmp_str);
				return i;
			}
		}
		tok = strtok(NULL, sep_str);
	}

	free(tmp_str);
	return SUB_API_NOTSET;
}

/*
 * auto-claiming and auto-release helper functions
 */
static int auto_claim(struct libusb_transfer *transfer, int *interface_number, int api_type)
{
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(
		transfer->dev_handle);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	int current_interface = *interface_number;
	int r = LIBUSB_SUCCESS;

	switch(api_type) {
	case USB_API_WINUSBX:
	case USB_API_HID:
		break;
	default:
		return LIBUSB_ERROR_INVALID_PARAM;
	}

	usbi_mutex_lock(&autoclaim_lock);
	if (current_interface < 0) { // No serviceable interface was found
		for (current_interface = 0; current_interface < USB_MAXINTERFACES; current_interface++) {
			// Must claim an interface of the same API type
			if ((priv->usb_interface[current_interface].apib->id == api_type)
					&& (libusb_claim_interface(transfer->dev_handle, current_interface) == LIBUSB_SUCCESS)) {
				usbi_dbg("auto-claimed interface %d for control request", current_interface);
				if (handle_priv->autoclaim_count[current_interface] != 0)
					usbi_warn(ctx, "program assertion failed - autoclaim_count was nonzero");
				handle_priv->autoclaim_count[current_interface]++;
				break;
			}
		}
		if (current_interface == USB_MAXINTERFACES) {
			usbi_err(ctx, "could not auto-claim any interface");
			r = LIBUSB_ERROR_NOT_FOUND;
		}
	} else {
		// If we have a valid interface that was autoclaimed, we must increment
		// its autoclaim count so that we can prevent an early release.
		if (handle_priv->autoclaim_count[current_interface] != 0)
			handle_priv->autoclaim_count[current_interface]++;
	}
	usbi_mutex_unlock(&autoclaim_lock);

	*interface_number = current_interface;
	return r;
}

static void auto_release(struct usbi_transfer *itransfer)
{
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	libusb_device_handle *dev_handle = transfer->dev_handle;
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	int r;

	usbi_mutex_lock(&autoclaim_lock);
	if (handle_priv->autoclaim_count[transfer_priv->interface_number] > 0) {
		handle_priv->autoclaim_count[transfer_priv->interface_number]--;
		if (handle_priv->autoclaim_count[transfer_priv->interface_number] == 0) {
			r = libusb_release_interface(dev_handle, transfer_priv->interface_number);
			if (r == LIBUSB_SUCCESS)
				usbi_dbg("auto-released interface %d", transfer_priv->interface_number);
			else
				usbi_dbg("failed to auto-release interface %d (%s)",
					transfer_priv->interface_number, libusb_error_name((enum libusb_error)r));
		}
	}
	usbi_mutex_unlock(&autoclaim_lock);
}

/* Windows version dtection */
static BOOL is_x64(void)
{
	BOOL ret = FALSE;

	// Detect if we're running a 32 or 64 bit system
	if (sizeof(uintptr_t) < 8) {
		if (pIsWow64Process != NULL)
			pIsWow64Process(GetCurrentProcess(), &ret);
	} else {
		ret = TRUE;
	}

	return ret;
}

static void get_windows_version(void)
{
	OSVERSIONINFOEXA vi, vi2;
	const char *w = 0;
	const char *w64 = "32 bit";
	char *vptr;
	size_t vlen;
	unsigned major, minor;
	ULONGLONG major_equal, minor_equal;
	BOOL ws;

	memset(&vi, 0, sizeof(vi));
	vi.dwOSVersionInfoSize = sizeof(vi);
	if (!GetVersionExA((OSVERSIONINFOA *)&vi)) {
		memset(&vi, 0, sizeof(vi));
		vi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOA);
		if (!GetVersionExA((OSVERSIONINFOA *)&vi))
			return;
	}

	if (vi.dwPlatformId == VER_PLATFORM_WIN32_NT) {
		if (vi.dwMajorVersion > 6 || (vi.dwMajorVersion == 6 && vi.dwMinorVersion >= 2)) {
			// Starting with Windows 8.1 Preview, GetVersionEx() does no longer report the actual OS version
			// See: http://msdn.microsoft.com/en-us/library/windows/desktop/dn302074.aspx

			major_equal = VerSetConditionMask(0, VER_MAJORVERSION, VER_EQUAL);
			for (major = vi.dwMajorVersion; major <= 9; major++) {
				memset(&vi2, 0, sizeof(vi2));
				vi2.dwOSVersionInfoSize = sizeof(vi2);
				vi2.dwMajorVersion = major;
				if (!VerifyVersionInfoA(&vi2, VER_MAJORVERSION, major_equal))
					continue;

				if (vi.dwMajorVersion < major) {
					vi.dwMajorVersion = major;
					vi.dwMinorVersion = 0;
				}

				minor_equal = VerSetConditionMask(0, VER_MINORVERSION, VER_EQUAL);
				for (minor = vi.dwMinorVersion; minor <= 9; minor++) {
					memset(&vi2, 0, sizeof(vi2));
					vi2.dwOSVersionInfoSize = sizeof(vi2);
					vi2.dwMinorVersion = minor;
					if (!VerifyVersionInfoA(&vi2, VER_MINORVERSION, minor_equal))
						continue;

					vi.dwMinorVersion = minor;
					break;
				}

				break;
			}
		}

		if (vi.dwMajorVersion <= 0xf && vi.dwMinorVersion <= 0xf) {
			ws = (vi.wProductType <= VER_NT_WORKSTATION);
			windows_version = vi.dwMajorVersion << 4 | vi.dwMinorVersion;
			switch (windows_version) {
			case 0x50: w = "2000"; break;
			case 0x51: w = "XP"; break;
			case 0x52: w = ("2003"); break;
			case 0x60: w = (ws ? "Vista" : "2008"); break;
			case 0x61: w = (ws ? "7" : "2008_R2"); break;
			case 0x62: w = (ws ? "8" : "2012"); break;
			case 0x63: w = (ws ? "8.1": "2012_R2"); break;
			case 0x64: w = (ws ? "10": "2015"); break;
			default:
				if (windows_version < 0x50)
					windows_version = WINDOWS_UNSUPPORTED;
				else
					w = "11 or later";
				break;
			}
		}
	}

	if (is_x64())
		w64 = "64-bit";

	vptr = &windows_version_str[sizeof("Windows ") - 1];
	vlen = sizeof(windows_version_str) - sizeof("Windows ") - 1;
	if (!w)
		safe_sprintf(vptr, vlen, "%s %u.%u %s", (vi.dwPlatformId == VER_PLATFORM_WIN32_NT ? "NT" : "??"),
			(unsigned int)vi.dwMajorVersion, (unsigned int)vi.dwMinorVersion, w64);
	else if (vi.wServicePackMinor)
		safe_sprintf(vptr, vlen, "%s SP%u.%u %s", w, vi.wServicePackMajor, vi.wServicePackMinor, w64);
	else if (vi.wServicePackMajor)
		safe_sprintf(vptr, vlen, "%s SP%u %s", w, vi.wServicePackMajor, w64);
	else
		safe_sprintf(vptr, vlen, "%s %s", w, w64);
}

/*
 * init: libusb backend init function
 *
 * This function enumerates the HCDs (Host Controller Drivers) and populates our private HCD list
 * In our implementation, we equate Windows' "HCD" to libusb's "bus". Note that bus is zero indexed.
 * HCDs are not expected to change after init (might not hold true for hot pluggable USB PCI card?)
 */
static int windows_init(struct libusb_context *ctx)
{
	int i, r = LIBUSB_ERROR_OTHER;
	HANDLE semaphore;
	char sem_name[11 + 8 + 1]; // strlen("libusb_init") + (32-bit hex PID) + '\0'

	sprintf(sem_name, "libusb_init%08X", (unsigned int)(GetCurrentProcessId() & 0xFFFFFFFF));
	semaphore = CreateSemaphoreA(NULL, 1, 1, sem_name);
	if (semaphore == NULL) {
		usbi_err(ctx, "could not create semaphore: %s", windows_error_str(0));
		return LIBUSB_ERROR_NO_MEM;
	}

	// A successful wait brings our semaphore count to 0 (unsignaled)
	// => any concurent wait stalls until the semaphore's release
	if (WaitForSingleObject(semaphore, INFINITE) != WAIT_OBJECT_0) {
		usbi_err(ctx, "failure to access semaphore: %s", windows_error_str(0));
		CloseHandle(semaphore);
		return LIBUSB_ERROR_NO_MEM;
	}

	// NB: concurrent usage supposes that init calls are equally balanced with
	// exit calls. If init is called more than exit, we will not exit properly
	if (++concurrent_usage == 0) { // First init?
		get_windows_version();
		usbi_dbg(windows_version_str);

		if (windows_version == WINDOWS_UNSUPPORTED) {
			usbi_err(ctx, "This version of Windows is NOT supported");
			r = LIBUSB_ERROR_NOT_SUPPORTED;
			goto init_exit;
		}

		// We need a lock for proper auto-release
		usbi_mutex_init(&autoclaim_lock);

		// Initialize pollable file descriptors
		init_polling();

		// Load DLL imports
		if (init_dlls() != LIBUSB_SUCCESS) {
			usbi_err(ctx, "could not resolve DLL functions");
			goto init_exit;
		}

		// Initialize the low level APIs (we don't care about errors at this stage)
		for (i = 0; i < USB_API_MAX; i++)
			usb_api_backend[i].init(SUB_API_NOTSET, ctx);

		r = windows_common_init(ctx);
		if (r)
			goto init_exit;
	}
	// At this stage, either we went through full init successfully, or didn't need to
	r = LIBUSB_SUCCESS;

init_exit: // Holds semaphore here.
	if (!concurrent_usage && r != LIBUSB_SUCCESS) { // First init failed?
		for (i = 0; i < USB_API_MAX; i++)
			usb_api_backend[i].exit(SUB_API_NOTSET);
		exit_dlls();
		exit_polling();
		windows_common_exit();
		usbi_mutex_destroy(&autoclaim_lock);
	}

	if (r != LIBUSB_SUCCESS)
		--concurrent_usage; // Not expected to call libusb_exit if we failed.

	ReleaseSemaphore(semaphore, 1, NULL); // increase count back to 1
	CloseHandle(semaphore);
	return r;
}

/*
 * HCD (root) hubs need to have their device descriptor manually populated
 *
 * Note that, like Microsoft does in the device manager, we populate the
 * Vendor and Device ID for HCD hubs with the ones from the PCI HCD device.
 */
static int force_hcd_device_descriptor(struct libusb_device *dev)
{
	struct windows_device_priv *parent_priv, *priv = _device_priv(dev);
	struct libusb_context *ctx = DEVICE_CTX(dev);
	int vid, pid;

	dev->num_configurations = 1;
	priv->dev_descriptor.bLength = sizeof(USB_DEVICE_DESCRIPTOR);
	priv->dev_descriptor.bDescriptorType = USB_DEVICE_DESCRIPTOR_TYPE;
	priv->dev_descriptor.bNumConfigurations = 1;
	priv->active_config = 1;

	if (priv->parent_dev == NULL) {
		usbi_err(ctx, "program assertion failed - HCD hub has no parent");
		return LIBUSB_ERROR_NO_DEVICE;
	}

	parent_priv = _device_priv(priv->parent_dev);
	if (sscanf(parent_priv->path, "\\\\.\\PCI#VEN_%04x&DEV_%04x%*s", &vid, &pid) == 2) {
		priv->dev_descriptor.idVendor = (uint16_t)vid;
		priv->dev_descriptor.idProduct = (uint16_t)pid;
	} else {
		usbi_warn(ctx, "could not infer VID/PID of HCD hub from '%s'", parent_priv->path);
		priv->dev_descriptor.idVendor = 0x1d6b; // Linux Foundation root hub
		priv->dev_descriptor.idProduct = 1;
	}

	return LIBUSB_SUCCESS;
}

/*
 * fetch and cache all the config descriptors through I/O
 */
static int cache_config_descriptors(struct libusb_device *dev, HANDLE hub_handle, char *device_id)
{
	DWORD size, ret_size;
	struct libusb_context *ctx = DEVICE_CTX(dev);
	struct windows_device_priv *priv = _device_priv(dev);
	int r;
	uint8_t i;

	USB_CONFIGURATION_DESCRIPTOR_SHORT cd_buf_short; // dummy request
	PUSB_DESCRIPTOR_REQUEST cd_buf_actual = NULL;    // actual request
	PUSB_CONFIGURATION_DESCRIPTOR cd_data = NULL;

	if (dev->num_configurations == 0)
		return LIBUSB_ERROR_INVALID_PARAM;

	priv->config_descriptor = calloc(dev->num_configurations, sizeof(unsigned char *));
	if (priv->config_descriptor == NULL)
		return LIBUSB_ERROR_NO_MEM;

	for (i = 0; i < dev->num_configurations; i++)
		priv->config_descriptor[i] = NULL;

	for (i = 0, r = LIBUSB_SUCCESS; ; i++) {
		// safe loop: release all dynamic resources
		safe_free(cd_buf_actual);

		// safe loop: end of loop condition
		if ((i >= dev->num_configurations) || (r != LIBUSB_SUCCESS))
			break;

		size = sizeof(USB_CONFIGURATION_DESCRIPTOR_SHORT);
		memset(&cd_buf_short, 0, size);

		cd_buf_short.req.ConnectionIndex = (ULONG)priv->port;
		cd_buf_short.req.SetupPacket.bmRequest = LIBUSB_ENDPOINT_IN;
		cd_buf_short.req.SetupPacket.bRequest = USB_REQUEST_GET_DESCRIPTOR;
		cd_buf_short.req.SetupPacket.wValue = (USB_CONFIGURATION_DESCRIPTOR_TYPE << 8) | i;
		cd_buf_short.req.SetupPacket.wIndex = 0;
		cd_buf_short.req.SetupPacket.wLength = (USHORT)(size - sizeof(USB_DESCRIPTOR_REQUEST));

		// Dummy call to get the required data size. Initial failures are reported as info rather
		// than error as they can occur for non-penalizing situations, such as with some hubs.
		// coverity[tainted_data_argument]
		if (!DeviceIoControl(hub_handle, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, &cd_buf_short, size,
			&cd_buf_short, size, &ret_size, NULL)) {
			usbi_info(ctx, "could not access configuration descriptor (dummy) for '%s': %s", device_id, windows_error_str(0));
			LOOP_BREAK(LIBUSB_ERROR_IO);
		}

		if ((ret_size != size) || (cd_buf_short.data.wTotalLength < sizeof(USB_CONFIGURATION_DESCRIPTOR))) {
			usbi_info(ctx, "unexpected configuration descriptor size (dummy) for '%s'.", device_id);
			LOOP_BREAK(LIBUSB_ERROR_IO);
		}

		size = sizeof(USB_DESCRIPTOR_REQUEST) + cd_buf_short.data.wTotalLength;
		cd_buf_actual = calloc(1, size);
		if (cd_buf_actual == NULL) {
			usbi_err(ctx, "could not allocate configuration descriptor buffer for '%s'.", device_id);
			LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
		}

		// Actual call
		cd_buf_actual->ConnectionIndex = (ULONG)priv->port;
		cd_buf_actual->SetupPacket.bmRequest = LIBUSB_ENDPOINT_IN;
		cd_buf_actual->SetupPacket.bRequest = USB_REQUEST_GET_DESCRIPTOR;
		cd_buf_actual->SetupPacket.wValue = (USB_CONFIGURATION_DESCRIPTOR_TYPE << 8) | i;
		cd_buf_actual->SetupPacket.wIndex = 0;
		cd_buf_actual->SetupPacket.wLength = (USHORT)(size - sizeof(USB_DESCRIPTOR_REQUEST));

		if (!DeviceIoControl(hub_handle, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, cd_buf_actual, size,
			cd_buf_actual, size, &ret_size, NULL)) {
			usbi_err(ctx, "could not access configuration descriptor (actual) for '%s': %s", device_id, windows_error_str(0));
			LOOP_BREAK(LIBUSB_ERROR_IO);
		}

		cd_data = (PUSB_CONFIGURATION_DESCRIPTOR)((UCHAR *)cd_buf_actual + sizeof(USB_DESCRIPTOR_REQUEST));

		if ((size != ret_size) || (cd_data->wTotalLength != cd_buf_short.data.wTotalLength)) {
			usbi_err(ctx, "unexpected configuration descriptor size (actual) for '%s'.", device_id);
			LOOP_BREAK(LIBUSB_ERROR_IO);
		}

		if (cd_data->bDescriptorType != USB_CONFIGURATION_DESCRIPTOR_TYPE) {
			usbi_err(ctx, "not a configuration descriptor for '%s'", device_id);
			LOOP_BREAK(LIBUSB_ERROR_IO);
		}

		usbi_dbg("cached config descriptor %d (bConfigurationValue=%u, %u bytes)",
			i, cd_data->bConfigurationValue, cd_data->wTotalLength);

		// Cache the descriptor
		priv->config_descriptor[i] = malloc(cd_data->wTotalLength);
		if (priv->config_descriptor[i] == NULL)
			LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
		memcpy(priv->config_descriptor[i], cd_data, cd_data->wTotalLength);
	}
	return LIBUSB_SUCCESS;
}

/*
 * Populate a libusb device structure
 */
static int init_device(struct libusb_device *dev, struct libusb_device *parent_dev,
	uint8_t port_number, char *device_id, DWORD devinst)
{
	HANDLE handle;
	DWORD size;
	USB_NODE_CONNECTION_INFORMATION_EX conn_info;
	USB_NODE_CONNECTION_INFORMATION_EX_V2 conn_info_v2;
	struct windows_device_priv *priv, *parent_priv;
	struct libusb_context *ctx;
	struct libusb_device *tmp_dev;
	unsigned long tmp_id;
	unsigned i;

	if ((dev == NULL) || (parent_dev == NULL))
		return LIBUSB_ERROR_NOT_FOUND;

	ctx = DEVICE_CTX(dev);
	priv = _device_priv(dev);
	parent_priv = _device_priv(parent_dev);
	if (parent_priv->apib->id != USB_API_HUB) {
		usbi_warn(ctx, "parent for device '%s' is not a hub", device_id);
		return LIBUSB_ERROR_NOT_FOUND;
	}

	// It is possible for the parent hub not to have been initialized yet
	// If that's the case, lookup the ancestors to set the bus number
	if (parent_dev->bus_number == 0) {
		for (i = 2; ; i++) {
			tmp_id = get_ancestor_session_id(devinst, i);
			if (tmp_id == 0)
				break;

			tmp_dev = usbi_get_device_by_session_id(ctx, tmp_id);
			if (tmp_dev == NULL)
				continue;

			if (tmp_dev->bus_number != 0) {
				usbi_dbg("got bus number from ancestor #%u", i);
				parent_dev->bus_number = tmp_dev->bus_number;
				libusb_unref_device(tmp_dev);
				break;
			}

			libusb_unref_device(tmp_dev);
		}
	}

	if (parent_dev->bus_number == 0) {
		usbi_err(ctx, "program assertion failed: unable to find ancestor bus number for '%s'", device_id);
		return LIBUSB_ERROR_NOT_FOUND;
	}

	dev->bus_number = parent_dev->bus_number;
	priv->port = port_number;
	dev->port_number = port_number;
	priv->depth = parent_priv->depth + 1;
	priv->parent_dev = parent_dev;
	dev->parent_dev = parent_dev;

	// If the device address is already set, we can stop here
	if (dev->device_address != 0)
		return LIBUSB_SUCCESS;

	memset(&conn_info, 0, sizeof(conn_info));
	if (priv->depth != 0) { // Not a HCD hub
		handle = CreateFileA(parent_priv->path, GENERIC_WRITE, FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
			FILE_FLAG_OVERLAPPED, NULL);
		if (handle == INVALID_HANDLE_VALUE) {
			usbi_warn(ctx, "could not open hub %s: %s", parent_priv->path, windows_error_str(0));
			return LIBUSB_ERROR_ACCESS;
		}

		size = sizeof(conn_info);
		conn_info.ConnectionIndex = (ULONG)port_number;
		// coverity[tainted_data_argument]
		if (!DeviceIoControl(handle, IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX, &conn_info, size,
			&conn_info, size, &size, NULL)) {
			usbi_warn(ctx, "could not get node connection information for device '%s': %s",
				device_id, windows_error_str(0));
			safe_closehandle(handle);
			return LIBUSB_ERROR_NO_DEVICE;
		}

		if (conn_info.ConnectionStatus == NoDeviceConnected) {
			usbi_err(ctx, "device '%s' is no longer connected!", device_id);
			safe_closehandle(handle);
			return LIBUSB_ERROR_NO_DEVICE;
		}

		memcpy(&priv->dev_descriptor, &(conn_info.DeviceDescriptor), sizeof(USB_DEVICE_DESCRIPTOR));
		dev->num_configurations = priv->dev_descriptor.bNumConfigurations;
		priv->active_config = conn_info.CurrentConfigurationValue;
		usbi_dbg("found %u configurations (active conf: %u)", dev->num_configurations, priv->active_config);

		// If we can't read the config descriptors, just set the number of confs to zero
		if (cache_config_descriptors(dev, handle, device_id) != LIBUSB_SUCCESS) {
			dev->num_configurations = 0;
			priv->dev_descriptor.bNumConfigurations = 0;
		}

		// In their great wisdom, Microsoft decided to BREAK the USB speed report between Windows 7 and Windows 8
		if (windows_version >= WINDOWS_8) {
			memset(&conn_info_v2, 0, sizeof(conn_info_v2));
			size = sizeof(conn_info_v2);
			conn_info_v2.ConnectionIndex = (ULONG)port_number;
			conn_info_v2.Length = size;
			conn_info_v2.SupportedUsbProtocols.Usb300 = 1;
			if (!DeviceIoControl(handle, IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX_V2,
				&conn_info_v2, size, &conn_info_v2, size, &size, NULL)) {
				usbi_warn(ctx, "could not get node connection information (V2) for device '%s': %s",
					device_id,  windows_error_str(0));
			} else if (conn_info_v2.Flags.DeviceIsOperatingAtSuperSpeedOrHigher) {
				conn_info.Speed = 3;
			}
		}

		safe_closehandle(handle);

		if (conn_info.DeviceAddress > UINT8_MAX)
			usbi_err(ctx, "program assertion failed: device address overflow");

		dev->device_address = (uint8_t)conn_info.DeviceAddress + 1;
		if (dev->device_address == 1)
			usbi_err(ctx, "program assertion failed: device address collision with root hub");

		switch (conn_info.Speed) {
		case 0: dev->speed = LIBUSB_SPEED_LOW; break;
		case 1: dev->speed = LIBUSB_SPEED_FULL; break;
		case 2: dev->speed = LIBUSB_SPEED_HIGH; break;
		case 3: dev->speed = LIBUSB_SPEED_SUPER; break;
		default:
			usbi_warn(ctx, "Got unknown device speed %u", conn_info.Speed);
			break;
		}
	} else {
		dev->device_address = 1; // root hubs are set to use device number 1
		force_hcd_device_descriptor(dev);
	}

	usbi_sanitize_device(dev);

	usbi_dbg("(bus: %u, addr: %u, depth: %u, port: %u): '%s'",
		dev->bus_number, dev->device_address, priv->depth, priv->port, device_id);

	return LIBUSB_SUCCESS;
}

// Returns the api type, or 0 if not found/unsupported
static void get_api_type(struct libusb_context *ctx, HDEVINFO *dev_info,
	SP_DEVINFO_DATA *dev_info_data, int *api, int *sub_api)
{
	// Precedence for filter drivers vs driver is in the order of this array
	struct driver_lookup lookup[3] = {
		{"\0\0", SPDRP_SERVICE, "driver"},
		{"\0\0", SPDRP_UPPERFILTERS, "upper filter driver"},
		{"\0\0", SPDRP_LOWERFILTERS, "lower filter driver"}
	};
	DWORD size, reg_type;
	unsigned k, l;
	int i, j;

	*api = USB_API_UNSUPPORTED;
	*sub_api = SUB_API_NOTSET;

	// Check the service & filter names to know the API we should use
	for (k = 0; k < 3; k++) {
		if (pSetupDiGetDeviceRegistryPropertyA(*dev_info, dev_info_data, lookup[k].reg_prop,
			&reg_type, (BYTE *)lookup[k].list, MAX_KEY_LENGTH, &size)) {
			// Turn the REG_SZ SPDRP_SERVICE into REG_MULTI_SZ
			if (lookup[k].reg_prop == SPDRP_SERVICE)
				// our buffers are MAX_KEY_LENGTH + 1 so we can overflow if needed
				lookup[k].list[safe_strlen(lookup[k].list) + 1] = 0;

			// MULTI_SZ is a pain to work with. Turn it into something much more manageable
			// NB: none of the driver names we check against contain LIST_SEPARATOR,
			// (currently ';'), so even if an unsuported one does, it's not an issue
			for (l = 0; (lookup[k].list[l] != 0) || (lookup[k].list[l + 1] != 0); l++) {
				if (lookup[k].list[l] == 0)
					lookup[k].list[l] = LIST_SEPARATOR;
			}
			usbi_dbg("%s(s): %s", lookup[k].designation, lookup[k].list);
		} else {
			if (GetLastError() != ERROR_INVALID_DATA)
				usbi_dbg("could not access %s: %s", lookup[k].designation, windows_error_str(0));
			lookup[k].list[0] = 0;
		}
	}

	for (i = 1; i < USB_API_MAX; i++) {
		for (k = 0; k < 3; k++) {
			j = get_sub_api(lookup[k].list, i);
			if (j >= 0) {
				usbi_dbg("matched %s name against %s", lookup[k].designation,
					(i != USB_API_WINUSBX) ? usb_api_backend[i].designation : sub_api_name[j]);
				*api = i;
				*sub_api = j;
				return;
			}
		}
	}
}

static int set_composite_interface(struct libusb_context *ctx, struct libusb_device *dev,
	char *dev_interface_path, char *device_id, int api, int sub_api)
{
	unsigned i;
	struct windows_device_priv *priv = _device_priv(dev);
	int interface_number;

	if (priv->apib->id != USB_API_COMPOSITE) {
		usbi_err(ctx, "program assertion failed: '%s' is not composite", device_id);
		return LIBUSB_ERROR_NO_DEVICE;
	}

	// Because MI_## are not necessarily in sequential order (some composite
	// devices will have only MI_00 & MI_03 for instance), we retrieve the actual
	// interface number from the path's MI value
	interface_number = 0;
	for (i = 0; device_id[i] != 0; ) {
		if ((device_id[i++] == 'M') && (device_id[i++] == 'I')
				&& (device_id[i++] == '_')) {
			interface_number = (device_id[i++] - '0') * 10;
			interface_number += device_id[i] - '0';
			break;
		}
	}

	if (device_id[i] == 0)
		usbi_warn(ctx, "failure to read interface number for %s. Using default value %d",
			device_id, interface_number);

	if (priv->usb_interface[interface_number].path != NULL) {
		if (api == USB_API_HID) {
			// HID devices can have multiple collections (COL##) for each MI_## interface
			usbi_dbg("interface[%d] already set - ignoring HID collection: %s",
				interface_number, device_id);
			return LIBUSB_ERROR_ACCESS;
		}
		// In other cases, just use the latest data
		safe_free(priv->usb_interface[interface_number].path);
	}

	usbi_dbg("interface[%d] = %s", interface_number, dev_interface_path);
	priv->usb_interface[interface_number].path = dev_interface_path;
	priv->usb_interface[interface_number].apib = &usb_api_backend[api];
	priv->usb_interface[interface_number].sub_api = sub_api;
	if ((api == USB_API_HID) && (priv->hid == NULL)) {
		priv->hid = calloc(1, sizeof(struct hid_device_priv));
		if (priv->hid == NULL)
			return LIBUSB_ERROR_NO_MEM;
	}

	return LIBUSB_SUCCESS;
}

static int set_hid_interface(struct libusb_context *ctx, struct libusb_device *dev,
	char *dev_interface_path)
{
	int i;
	struct windows_device_priv *priv = _device_priv(dev);

	if (priv->hid == NULL) {
		usbi_err(ctx, "program assertion failed: parent is not HID");
		return LIBUSB_ERROR_NO_DEVICE;
	} else if (priv->hid->nb_interfaces == USB_MAXINTERFACES) {
		usbi_err(ctx, "program assertion failed: max USB interfaces reached for HID device");
		return LIBUSB_ERROR_NO_DEVICE;
	}

	for (i = 0; i < priv->hid->nb_interfaces; i++) {
		if (safe_strcmp(priv->usb_interface[i].path, dev_interface_path) == 0) {
			usbi_dbg("interface[%d] already set to %s", i, dev_interface_path);
			return LIBUSB_ERROR_ACCESS;
		}
	}

	priv->usb_interface[priv->hid->nb_interfaces].path = dev_interface_path;
	priv->usb_interface[priv->hid->nb_interfaces].apib = &usb_api_backend[USB_API_HID];
	usbi_dbg("interface[%u] = %s", priv->hid->nb_interfaces, dev_interface_path);
	priv->hid->nb_interfaces++;
	return LIBUSB_SUCCESS;
}

/*
 * get_device_list: libusb backend device enumeration function
 */
static int windows_get_device_list(struct libusb_context *ctx, struct discovered_devs **_discdevs)
{
	struct discovered_devs *discdevs;
	HDEVINFO dev_info = { 0 };
	const char *usb_class[] = {"USB", "NUSB3", "IUSB3", "IARUSB3"};
	SP_DEVINFO_DATA dev_info_data = { 0 };
	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
	GUID hid_guid;
#define MAX_ENUM_GUIDS 64
	const GUID *guid[MAX_ENUM_GUIDS];
#define HCD_PASS 0
#define HUB_PASS 1
#define GEN_PASS 2
#define DEV_PASS 3
#define HID_PASS 4
	int r = LIBUSB_SUCCESS;
	int api, sub_api;
	size_t class_index = 0;
	unsigned int nb_guids, pass, i, j, ancestor;
	char path[MAX_PATH_LENGTH];
	char strbuf[MAX_PATH_LENGTH];
	struct libusb_device *dev, *parent_dev;
	struct windows_device_priv *priv, *parent_priv;
	char *dev_interface_path = NULL;
	char *dev_id_path = NULL;
	unsigned long session_id;
	DWORD size, reg_type, port_nr, install_state;
	HKEY key;
	WCHAR guid_string_w[MAX_GUID_STRING_LENGTH];
	GUID *if_guid;
	LONG s;
	// Keep a list of newly allocated devs to unref
	libusb_device **unref_list, **new_unref_list;
	unsigned int unref_size = 64;
	unsigned int unref_cur = 0;

	// PASS 1 : (re)enumerate HCDs (allows for HCD hotplug)
	// PASS 2 : (re)enumerate HUBS
	// PASS 3 : (re)enumerate generic USB devices (including driverless)
	//           and list additional USB device interface GUIDs to explore
	// PASS 4 : (re)enumerate master USB devices that have a device interface
	// PASS 5+: (re)enumerate device interfaced GUIDs (including HID) and
	//           set the device interfaces.

	// Init the GUID table
	guid[HCD_PASS] = &GUID_DEVINTERFACE_USB_HOST_CONTROLLER;
	guid[HUB_PASS] = &GUID_DEVINTERFACE_USB_HUB;
	guid[GEN_PASS] = NULL;
	guid[DEV_PASS] = &GUID_DEVINTERFACE_USB_DEVICE;
	HidD_GetHidGuid(&hid_guid);
	guid[HID_PASS] = &hid_guid;
	nb_guids = HID_PASS + 1;

	unref_list = calloc(unref_size, sizeof(libusb_device *));
	if (unref_list == NULL)
		return LIBUSB_ERROR_NO_MEM;

	for (pass = 0; ((pass < nb_guids) && (r == LIBUSB_SUCCESS)); pass++) {
//#define ENUM_DEBUG
#if defined(ENABLE_LOGGING) && defined(ENUM_DEBUG)
		const char *passname[] = { "HCD", "HUB", "GEN", "DEV", "HID", "EXT" };
		usbi_dbg("#### PROCESSING %ss %s", passname[(pass <= HID_PASS) ? pass : (HID_PASS + 1)],
			(pass != GEN_PASS) ? guid_to_string(guid[pass]) : "");
#endif
		for (i = 0; ; i++) {
			// safe loop: free up any (unprotected) dynamic resource
			// NB: this is always executed before breaking the loop
			safe_free(dev_interface_details);
			safe_free(dev_interface_path);
			safe_free(dev_id_path);
			priv = parent_priv = NULL;
			dev = parent_dev = NULL;

			// Safe loop: end of loop conditions
			if (r != LIBUSB_SUCCESS)
				break;

			if ((pass == HCD_PASS) && (i == UINT8_MAX)) {
				usbi_warn(ctx, "program assertion failed - found more than %d buses, skipping the rest.", UINT8_MAX);
				break;
			}

			if (pass != GEN_PASS) {
				// Except for GEN, all passes deal with device interfaces
				dev_interface_details = get_interface_details(ctx, &dev_info, &dev_info_data, guid[pass], i);
				if (dev_interface_details == NULL)
					break;

				dev_interface_path = sanitize_path(dev_interface_details->DevicePath);
				if (dev_interface_path == NULL) {
					usbi_warn(ctx, "could not sanitize device interface path for '%s'", dev_interface_details->DevicePath);
					continue;
				}
			} else {
				// Workaround for a Nec/Renesas USB 3.0 driver bug where root hubs are
				// being listed under the "NUSB3" PnP Symbolic Name rather than "USB".
				// The Intel USB 3.0 driver behaves similar, but uses "IUSB3"
				// The Intel Alpine Ridge USB 3.1 driver uses "IARUSB3"
				for (; class_index < ARRAYSIZE(usb_class); class_index++) {
					if (get_devinfo_data(ctx, &dev_info, &dev_info_data, usb_class[class_index], i))
						break;
					i = 0;
				}
				if (class_index >= ARRAYSIZE(usb_class))
					break;
			}

			// Read the Device ID path. This is what we'll use as UID
			// Note that if the device is plugged in a different port or hub, the Device ID changes
			if (CM_Get_Device_IDA(dev_info_data.DevInst, path, sizeof(path), 0) != CR_SUCCESS) {
				usbi_warn(ctx, "could not read the device id path for devinst %X, skipping",
					(unsigned int)dev_info_data.DevInst);
				continue;
			}

			dev_id_path = sanitize_path(path);
			if (dev_id_path == NULL) {
				usbi_warn(ctx, "could not sanitize device id path for devinst %X, skipping",
					(unsigned int)dev_info_data.DevInst);
				continue;
			}
#ifdef ENUM_DEBUG
			usbi_dbg("PRO: %s", dev_id_path);
#endif

			// The SPDRP_ADDRESS for USB devices is the device port number on the hub
			port_nr = 0;
			if ((pass >= HUB_PASS) && (pass <= GEN_PASS)) {
				if ((!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_ADDRESS,
					&reg_type, (BYTE *)&port_nr, 4, &size)) || (size != 4)) {
					usbi_warn(ctx, "could not retrieve port number for device '%s', skipping: %s",
						dev_id_path, windows_error_str(0));
					continue;
				}
			}

			// Set API to use or get additional data from generic pass
			api = USB_API_UNSUPPORTED;
			sub_api = SUB_API_NOTSET;
			switch (pass) {
			case HCD_PASS:
				break;
			case GEN_PASS:
				// We use the GEN pass to detect driverless devices...
				size = sizeof(strbuf);
				if (!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_DRIVER,
					&reg_type, (BYTE *)strbuf, size, &size)) {
						usbi_info(ctx, "The following device has no driver: '%s'", dev_id_path);
						usbi_info(ctx, "libusb will not be able to access it.");
				}
				// ...and to add the additional device interface GUIDs
				key = pSetupDiOpenDevRegKey(dev_info, &dev_info_data, DICS_FLAG_GLOBAL, 0, DIREG_DEV, KEY_READ);
				if (key != INVALID_HANDLE_VALUE) {
					size = sizeof(guid_string_w);
					s = pRegQueryValueExW(key, L"DeviceInterfaceGUIDs", NULL, &reg_type,
						(BYTE *)guid_string_w, &size);
					pRegCloseKey(key);
					if (s == ERROR_SUCCESS) {
						if (nb_guids >= MAX_ENUM_GUIDS) {
							// If this assert is ever reported, grow a GUID table dynamically
							usbi_err(ctx, "program assertion failed: too many GUIDs");
							LOOP_BREAK(LIBUSB_ERROR_OVERFLOW);
						}
						if_guid = calloc(1, sizeof(GUID));
						if (if_guid == NULL) {
							usbi_err(ctx, "could not calloc for if_guid: not enough memory");
							LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
						}
						pCLSIDFromString(guid_string_w, if_guid);
						guid[nb_guids++] = if_guid;
						usbi_dbg("extra GUID: %s", guid_to_string(if_guid));
					}
				}
				break;
			case HID_PASS:
				api = USB_API_HID;
				break;
			default:
				// Get the API type (after checking that the driver installation is OK)
				if ((!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_INSTALL_STATE,
					&reg_type, (BYTE *)&install_state, 4, &size)) || (size != 4)) {
					usbi_warn(ctx, "could not detect installation state of driver for '%s': %s",
						dev_id_path, windows_error_str(0));
				} else if (install_state != 0) {
					usbi_warn(ctx, "driver for device '%s' is reporting an issue (code: %u) - skipping",
						dev_id_path, (unsigned int)install_state);
					continue;
				}
				get_api_type(ctx, &dev_info, &dev_info_data, &api, &sub_api);
				break;
			}

			// Find parent device (for the passes that need it)
			switch (pass) {
			case HCD_PASS:
			case DEV_PASS:
			case HUB_PASS:
				break;
			default:
				// Go through the ancestors until we see a face we recognize
				parent_dev = NULL;
				for (ancestor = 1; parent_dev == NULL; ancestor++) {
					session_id = get_ancestor_session_id(dev_info_data.DevInst, ancestor);
					if (session_id == 0)
						break;

					parent_dev = usbi_get_device_by_session_id(ctx, session_id);
				}

				if (parent_dev == NULL) {
					usbi_dbg("unlisted ancestor for '%s' (non USB HID, newly connected, etc.) - ignoring", dev_id_path);
					continue;
				}

				parent_priv = _device_priv(parent_dev);
				// virtual USB devices are also listed during GEN - don't process these yet
				if ((pass == GEN_PASS) && (parent_priv->apib->id != USB_API_HUB)) {
					libusb_unref_device(parent_dev);
					continue;
				}

				break;
			}

			// Create new or match existing device, using the (hashed) device_id as session id
			if (pass <= DEV_PASS) {	// For subsequent passes, we'll lookup the parent
				// These are the passes that create "new" devices
				session_id = htab_hash(dev_id_path);
				dev = usbi_get_device_by_session_id(ctx, session_id);
				if (dev == NULL) {
					if (pass == DEV_PASS) {
						// This can occur if the OS only reports a newly plugged device after we started enum
						usbi_warn(ctx, "'%s' was only detected in late pass (newly connected device?)"
							" - ignoring", dev_id_path);
						continue;
					}

					usbi_dbg("allocating new device for session [%lX]", session_id);
					dev = usbi_alloc_device(ctx, session_id);
					if (dev == NULL)
						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);

					priv = windows_device_priv_init(dev);
				} else {
					usbi_dbg("found existing device for session [%lX] (%u.%u)",
						session_id, dev->bus_number, dev->device_address);

					priv = _device_priv(dev);
					if (priv->parent_dev != NULL) {
						if (priv->parent_dev != parent_dev) {
							usbi_err(ctx, "program assertion failed - existing device should share parent");
						} else {
							// We hold a reference to parent_dev instance, but this device already
							// has a parent_dev reference (only one per child)
							libusb_unref_device(parent_dev);
						}
					}
				}

				// Keep track of devices that need unref
				unref_list[unref_cur++] = dev;
				if (unref_cur >= unref_size) {
					unref_size += 64;
					new_unref_list = usbi_reallocf(unref_list, unref_size * sizeof(libusb_device *));
					if (new_unref_list == NULL) {
						usbi_err(ctx, "could not realloc list for unref - aborting.");
						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
					} else {
						unref_list = new_unref_list;
					}
				}
			}

			// Setup device
			switch (pass) {
			case HCD_PASS:
				// If the hcd has already been setup, don't do it again
				if (priv->path != NULL)
					break;
				dev->bus_number = (uint8_t)(i + 1); // bus 0 is reserved for disconnected
				dev->device_address = 0;
				dev->num_configurations = 0;
				priv->apib = &usb_api_backend[USB_API_HUB];
				priv->sub_api = SUB_API_NOTSET;
				priv->depth = UINT8_MAX; // Overflow to 0 for HCD Hubs
				priv->path = dev_interface_path;
				dev_interface_path = NULL;
				break;
			case HUB_PASS:
			case DEV_PASS:
				// If the device has already been setup, don't do it again
				if (priv->path != NULL)
					break;
				// Take care of API initialization
				priv->path = dev_interface_path;
				dev_interface_path = NULL;
				priv->apib = &usb_api_backend[api];
				priv->sub_api = sub_api;
				switch(api) {
				case USB_API_COMPOSITE:
				case USB_API_HUB:
					break;
				case USB_API_HID:
					priv->hid = calloc(1, sizeof(struct hid_device_priv));
					if (priv->hid == NULL)
						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);

					priv->hid->nb_interfaces = 0;
					break;
				default:
					// For other devices, the first interface is the same as the device
					priv->usb_interface[0].path = _strdup(priv->path);
					if (priv->usb_interface[0].path == NULL)
						usbi_warn(ctx, "could not duplicate interface path '%s'", priv->path);
					// The following is needed if we want API calls to work for both simple
					// and composite devices.
					for(j = 0; j < USB_MAXINTERFACES; j++)
						priv->usb_interface[j].apib = &usb_api_backend[api];

					break;
				}
				break;
			case GEN_PASS:
				r = init_device(dev, parent_dev, (uint8_t)port_nr, dev_id_path, dev_info_data.DevInst);
				if (r == LIBUSB_SUCCESS) {
					// Append device to the list of discovered devices
					discdevs = discovered_devs_append(*_discdevs, dev);
					if (!discdevs)
						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);

					*_discdevs = discdevs;
				} else if (r == LIBUSB_ERROR_NO_DEVICE) {
					// This can occur if the device was disconnected but Windows hasn't
					// refreshed its enumeration yet - in that case, we ignore the device
					r = LIBUSB_SUCCESS;
				}
				break;
			default: // HID_PASS and later
				if (parent_priv->apib->id == USB_API_HID || parent_priv->apib->id == USB_API_COMPOSITE) {
					if (parent_priv->apib->id == USB_API_HID) {
						usbi_dbg("setting HID interface for [%lX]:", parent_dev->session_data);
						r = set_hid_interface(ctx, parent_dev, dev_interface_path);
					} else {
						usbi_dbg("setting composite interface for [%lX]:", parent_dev->session_data);
						r = set_composite_interface(ctx, parent_dev, dev_interface_path, dev_id_path, api, sub_api);
					}
					switch (r) {
					case LIBUSB_SUCCESS:
						dev_interface_path = NULL;
						break;
					case LIBUSB_ERROR_ACCESS:
						// interface has already been set => make sure dev_interface_path is freed then
						r = LIBUSB_SUCCESS;
						break;
					default:
						LOOP_BREAK(r);
						break;
					}
				}
				libusb_unref_device(parent_dev);
				break;
			}
		}
	}

	// Free any additional GUIDs
	for (pass = HID_PASS + 1; pass < nb_guids; pass++)
		safe_free(guid[pass]);

	// Unref newly allocated devs
	for (i = 0; i < unref_cur; i++)
		safe_unref_device(unref_list[i]);
	free(unref_list);

	return r;
}

/*
 * exit: libusb backend deinitialization function
 */
static void windows_exit(void)
{
	int i;
	HANDLE semaphore;
	char sem_name[11 + 8 + 1]; // strlen("libusb_init") + (32-bit hex PID) + '\0'

	sprintf(sem_name, "libusb_init%08X", (unsigned int)(GetCurrentProcessId() & 0xFFFFFFFF));
	semaphore = CreateSemaphoreA(NULL, 1, 1, sem_name);
	if (semaphore == NULL)
		return;

	// A successful wait brings our semaphore count to 0 (unsignaled)
	// => any concurent wait stalls until the semaphore release
	if (WaitForSingleObject(semaphore, INFINITE) != WAIT_OBJECT_0) {
		CloseHandle(semaphore);
		return;
	}

	// Only works if exits and inits are balanced exactly
	if (--concurrent_usage < 0) { // Last exit
		for (i = 0; i < USB_API_MAX; i++)
			usb_api_backend[i].exit(SUB_API_NOTSET);
		exit_dlls();
		exit_polling();
		windows_common_exit();
		usbi_mutex_destroy(&autoclaim_lock);
	}

	ReleaseSemaphore(semaphore, 1, NULL); // increase count back to 1
	CloseHandle(semaphore);
}

static int windows_get_device_descriptor(struct libusb_device *dev, unsigned char *buffer, int *host_endian)
{
	struct windows_device_priv *priv = _device_priv(dev);

	memcpy(buffer, &priv->dev_descriptor, DEVICE_DESC_LENGTH);
	*host_endian = 0;

	return LIBUSB_SUCCESS;
}

static int windows_get_config_descriptor(struct libusb_device *dev, uint8_t config_index, unsigned char *buffer, size_t len, int *host_endian)
{
	struct windows_device_priv *priv = _device_priv(dev);
	PUSB_CONFIGURATION_DESCRIPTOR config_header;
	size_t size;

	// config index is zero based
	if (config_index >= dev->num_configurations)
		return LIBUSB_ERROR_INVALID_PARAM;

	if ((priv->config_descriptor == NULL) || (priv->config_descriptor[config_index] == NULL))
		return LIBUSB_ERROR_NOT_FOUND;

	config_header = (PUSB_CONFIGURATION_DESCRIPTOR)priv->config_descriptor[config_index];

	size = MIN(config_header->wTotalLength, len);
	memcpy(buffer, priv->config_descriptor[config_index], size);
	*host_endian = 0;

	return (int)size;
}

static int windows_get_config_descriptor_by_value(struct libusb_device *dev, uint8_t bConfigurationValue,
	unsigned char **buffer, int *host_endian)
{
	struct windows_device_priv *priv = _device_priv(dev);
	PUSB_CONFIGURATION_DESCRIPTOR config_header;
	uint8_t index;

	*buffer = NULL;
	*host_endian = 0;

	if (priv->config_descriptor == NULL)
		return LIBUSB_ERROR_NOT_FOUND;

	for (index = 0; index < dev->num_configurations; index++) {
		config_header = (PUSB_CONFIGURATION_DESCRIPTOR)priv->config_descriptor[index];
		if (config_header->bConfigurationValue == bConfigurationValue) {
			*buffer = priv->config_descriptor[index];
			return (int)config_header->wTotalLength;
		}
	}

	return LIBUSB_ERROR_NOT_FOUND;
}

/*
 * return the cached copy of the active config descriptor
 */
static int windows_get_active_config_descriptor(struct libusb_device *dev, unsigned char *buffer, size_t len, int *host_endian)
{
	struct windows_device_priv *priv = _device_priv(dev);
	unsigned char *config_desc;
	int r;

	if (priv->active_config == 0)
		return LIBUSB_ERROR_NOT_FOUND;

	r = windows_get_config_descriptor_by_value(dev, priv->active_config, &config_desc, host_endian);
	if (r < 0)
		return r;

	len = MIN((size_t)r, len);
	memcpy(buffer, config_desc, len);
	return (int)len;
}

static int windows_open(struct libusb_device_handle *dev_handle)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);

	if (priv->apib == NULL) {
		usbi_err(ctx, "program assertion failed - device is not initialized");
		return LIBUSB_ERROR_NO_DEVICE;
	}

	return priv->apib->open(SUB_API_NOTSET, dev_handle);
}

static void windows_close(struct libusb_device_handle *dev_handle)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	priv->apib->close(SUB_API_NOTSET, dev_handle);
}

static int windows_get_configuration(struct libusb_device_handle *dev_handle, int *config)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	if (priv->active_config == 0) {
		*config = 0;
		return LIBUSB_ERROR_NOT_FOUND;
	}

	*config = priv->active_config;
	return LIBUSB_SUCCESS;
}

/*
 * from http://msdn.microsoft.com/en-us/library/ms793522.aspx: "The port driver
 * does not currently expose a service that allows higher-level drivers to set
 * the configuration."
 */
static int windows_set_configuration(struct libusb_device_handle *dev_handle, int config)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	int r = LIBUSB_SUCCESS;

	if (config >= USB_MAXCONFIG)
		return LIBUSB_ERROR_INVALID_PARAM;

	r = libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_OUT |
		LIBUSB_REQUEST_TYPE_STANDARD | LIBUSB_RECIPIENT_DEVICE,
		LIBUSB_REQUEST_SET_CONFIGURATION, (uint16_t)config,
		0, NULL, 0, 1000);

	if (r == LIBUSB_SUCCESS)
		priv->active_config = (uint8_t)config;

	return r;
}

static int windows_claim_interface(struct libusb_device_handle *dev_handle, int iface)
{
	int r = LIBUSB_SUCCESS;
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	safe_free(priv->usb_interface[iface].endpoint);
	priv->usb_interface[iface].nb_endpoints = 0;

	r = priv->apib->claim_interface(SUB_API_NOTSET, dev_handle, iface);

	if (r == LIBUSB_SUCCESS)
		r = windows_assign_endpoints(dev_handle, iface, 0);

	return r;
}

static int windows_set_interface_altsetting(struct libusb_device_handle *dev_handle, int iface, int altsetting)
{
	int r = LIBUSB_SUCCESS;
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	safe_free(priv->usb_interface[iface].endpoint);
	priv->usb_interface[iface].nb_endpoints = 0;

	r = priv->apib->set_interface_altsetting(SUB_API_NOTSET, dev_handle, iface, altsetting);

	if (r == LIBUSB_SUCCESS)
		r = windows_assign_endpoints(dev_handle, iface, altsetting);

	return r;
}

static int windows_release_interface(struct libusb_device_handle *dev_handle, int iface)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	return priv->apib->release_interface(SUB_API_NOTSET, dev_handle, iface);
}

static int windows_clear_halt(struct libusb_device_handle *dev_handle, unsigned char endpoint)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	return priv->apib->clear_halt(SUB_API_NOTSET, dev_handle, endpoint);
}

static int windows_reset_device(struct libusb_device_handle *dev_handle)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	return priv->apib->reset_device(SUB_API_NOTSET, dev_handle);
}

// The 3 functions below are unlikely to ever get supported on Windows
static int windows_kernel_driver_active(struct libusb_device_handle *dev_handle, int iface)
{
	return LIBUSB_ERROR_NOT_SUPPORTED;
}

static int windows_attach_kernel_driver(struct libusb_device_handle *dev_handle, int iface)
{
	return LIBUSB_ERROR_NOT_SUPPORTED;
}

static int windows_detach_kernel_driver(struct libusb_device_handle *dev_handle, int iface)
{
	return LIBUSB_ERROR_NOT_SUPPORTED;
}

static void windows_destroy_device(struct libusb_device *dev)
{
	windows_device_priv_release(dev);
}

void windows_clear_transfer_priv(struct usbi_transfer *itransfer)
{
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);

	usbi_free_fd(&transfer_priv->pollable_fd);
	safe_free(transfer_priv->hid_buffer);
	// When auto claim is in use, attempt to release the auto-claimed interface
	auto_release(itransfer);
}

static int submit_bulk_transfer(struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	int r;

	r = priv->apib->submit_bulk_transfer(SUB_API_NOTSET, itransfer);
	if (r != LIBUSB_SUCCESS)
		return r;

	usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd,
		(short)(IS_XFERIN(transfer) ? POLLIN : POLLOUT));

	return LIBUSB_SUCCESS;
}

static int submit_iso_transfer(struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	int r;

	r = priv->apib->submit_iso_transfer(SUB_API_NOTSET, itransfer);
	if (r != LIBUSB_SUCCESS)
		return r;

	usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd,
		(short)(IS_XFERIN(transfer) ? POLLIN : POLLOUT));

	return LIBUSB_SUCCESS;
}

static int submit_control_transfer(struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	int r;

	r = priv->apib->submit_control_transfer(SUB_API_NOTSET, itransfer);
	if (r != LIBUSB_SUCCESS)
		return r;

	usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd, POLLIN);

	return LIBUSB_SUCCESS;
}

static int windows_submit_transfer(struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);

	switch (transfer->type) {
	case LIBUSB_TRANSFER_TYPE_CONTROL:
		return submit_control_transfer(itransfer);
	case LIBUSB_TRANSFER_TYPE_BULK:
	case LIBUSB_TRANSFER_TYPE_INTERRUPT:
		if (IS_XFEROUT(transfer) && (transfer->flags & LIBUSB_TRANSFER_ADD_ZERO_PACKET))
			return LIBUSB_ERROR_NOT_SUPPORTED;
		return submit_bulk_transfer(itransfer);
	case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
		return submit_iso_transfer(itransfer);
	case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
		return LIBUSB_ERROR_NOT_SUPPORTED;
	default:
		usbi_err(TRANSFER_CTX(transfer), "unknown endpoint type %d", transfer->type);
		return LIBUSB_ERROR_INVALID_PARAM;
	}
}

static int windows_abort_control(struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);

	return priv->apib->abort_control(SUB_API_NOTSET, itransfer);
}

static int windows_abort_transfers(struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);

	return priv->apib->abort_transfers(SUB_API_NOTSET, itransfer);
}

static int windows_cancel_transfer(struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);

	switch (transfer->type) {
	case LIBUSB_TRANSFER_TYPE_CONTROL:
		return windows_abort_control(itransfer);
	case LIBUSB_TRANSFER_TYPE_BULK:
	case LIBUSB_TRANSFER_TYPE_INTERRUPT:
	case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
		return windows_abort_transfers(itransfer);
	case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
		return LIBUSB_ERROR_NOT_SUPPORTED;
	default:
		usbi_err(ITRANSFER_CTX(itransfer), "unknown endpoint type %d", transfer->type);
		return LIBUSB_ERROR_INVALID_PARAM;
	}
}

int windows_copy_transfer_data(struct usbi_transfer *itransfer, uint32_t io_size)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	return priv->apib->copy_transfer_data(SUB_API_NOTSET, itransfer, io_size);
}

struct winfd *windows_get_fd(struct usbi_transfer *transfer)
{
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(transfer);
	return &transfer_priv->pollable_fd;
}

void windows_get_overlapped_result(struct usbi_transfer *transfer, struct winfd *pollable_fd, DWORD *io_result, DWORD *io_size)
{
	if (HasOverlappedIoCompletedSync(pollable_fd->overlapped)) {
		*io_result = NO_ERROR;
		*io_size = (DWORD)pollable_fd->overlapped->InternalHigh;
	}
	else if (GetOverlappedResult(pollable_fd->handle, pollable_fd->overlapped, io_size, false)) {
		// Regular async overlapped
		*io_result = NO_ERROR;
	}
	else {
		*io_result = GetLastError();
	}
}

// NB: MSVC6 does not support named initializers.
const struct usbi_os_backend windows_backend = {
	"Windows",
	USBI_CAP_HAS_HID_ACCESS,
	windows_init,
	windows_exit,

	windows_get_device_list,
	NULL,				/* hotplug_poll */
	windows_open,
	windows_close,

	windows_get_device_descriptor,
	windows_get_active_config_descriptor,
	windows_get_config_descriptor,
	windows_get_config_descriptor_by_value,

	windows_get_configuration,
	windows_set_configuration,
	windows_claim_interface,
	windows_release_interface,

	windows_set_interface_altsetting,
	windows_clear_halt,
	windows_reset_device,

	NULL,				/* alloc_streams */
	NULL,				/* free_streams */

	NULL,				/* dev_mem_alloc */
	NULL,				/* dev_mem_free */

	windows_kernel_driver_active,
	windows_detach_kernel_driver,
	windows_attach_kernel_driver,

	windows_destroy_device,

	windows_submit_transfer,
	windows_cancel_transfer,
	windows_clear_transfer_priv,

	windows_handle_events,
	NULL,

	windows_clock_gettime,
#if defined(USBI_TIMERFD_AVAILABLE)
	NULL,
#endif
	sizeof(struct windows_device_priv),
	sizeof(struct windows_device_handle_priv),
	sizeof(struct windows_transfer_priv),
};


/*
 * USB API backends
 */
static int unsupported_init(int sub_api, struct libusb_context *ctx)
{
	return LIBUSB_SUCCESS;
}

static int unsupported_exit(int sub_api)
{
	return LIBUSB_SUCCESS;
}

static int unsupported_open(int sub_api, struct libusb_device_handle *dev_handle)
{
	PRINT_UNSUPPORTED_API(open);
}

static void unsupported_close(int sub_api, struct libusb_device_handle *dev_handle)
{
	usbi_dbg("unsupported API call for 'close'");
}

static int unsupported_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	PRINT_UNSUPPORTED_API(configure_endpoints);
}

static int unsupported_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	PRINT_UNSUPPORTED_API(claim_interface);
}

static int unsupported_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
{
	PRINT_UNSUPPORTED_API(set_interface_altsetting);
}

static int unsupported_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	PRINT_UNSUPPORTED_API(release_interface);
}

static int unsupported_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
{
	PRINT_UNSUPPORTED_API(clear_halt);
}

static int unsupported_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
{
	PRINT_UNSUPPORTED_API(reset_device);
}

static int unsupported_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	PRINT_UNSUPPORTED_API(submit_bulk_transfer);
}

static int unsupported_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	PRINT_UNSUPPORTED_API(submit_iso_transfer);
}

static int unsupported_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	PRINT_UNSUPPORTED_API(submit_control_transfer);
}

static int unsupported_abort_control(int sub_api, struct usbi_transfer *itransfer)
{
	PRINT_UNSUPPORTED_API(abort_control);
}

static int unsupported_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
{
	PRINT_UNSUPPORTED_API(abort_transfers);
}

static int unsupported_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
{
	PRINT_UNSUPPORTED_API(copy_transfer_data);
}

static int common_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	return LIBUSB_SUCCESS;
}

// These names must be uppercase
static const char *hub_driver_names[] = {"USBHUB", "USBHUB3", "USB3HUB", "NUSB3HUB", "RUSB3HUB", "FLXHCIH", "TIHUB3", "ETRONHUB3", "VIAHUB3", "ASMTHUB3", "IUSB3HUB", "VUSB3HUB", "AMDHUB30", "VHHUB", "AUSB3HUB"};
static const char *composite_driver_names[] = {"USBCCGP"};
static const char *winusbx_driver_names[] = WINUSBX_DRV_NAMES;
static const char *hid_driver_names[] = {"HIDUSB", "MOUHID", "KBDHID"};
const struct windows_usb_api_backend usb_api_backend[USB_API_MAX] = {
	{
		USB_API_UNSUPPORTED,
		"Unsupported API",
		NULL,
		0,
		unsupported_init,
		unsupported_exit,
		unsupported_open,
		unsupported_close,
		unsupported_configure_endpoints,
		unsupported_claim_interface,
		unsupported_set_interface_altsetting,
		unsupported_release_interface,
		unsupported_clear_halt,
		unsupported_reset_device,
		unsupported_submit_bulk_transfer,
		unsupported_submit_iso_transfer,
		unsupported_submit_control_transfer,
		unsupported_abort_control,
		unsupported_abort_transfers,
		unsupported_copy_transfer_data,
	},
	{
		USB_API_HUB,
		"HUB API",
		hub_driver_names,
		ARRAYSIZE(hub_driver_names),
		unsupported_init,
		unsupported_exit,
		unsupported_open,
		unsupported_close,
		unsupported_configure_endpoints,
		unsupported_claim_interface,
		unsupported_set_interface_altsetting,
		unsupported_release_interface,
		unsupported_clear_halt,
		unsupported_reset_device,
		unsupported_submit_bulk_transfer,
		unsupported_submit_iso_transfer,
		unsupported_submit_control_transfer,
		unsupported_abort_control,
		unsupported_abort_transfers,
		unsupported_copy_transfer_data,
	},
	{
		USB_API_COMPOSITE,
		"Composite API",
		composite_driver_names,
		ARRAYSIZE(composite_driver_names),
		composite_init,
		composite_exit,
		composite_open,
		composite_close,
		common_configure_endpoints,
		composite_claim_interface,
		composite_set_interface_altsetting,
		composite_release_interface,
		composite_clear_halt,
		composite_reset_device,
		composite_submit_bulk_transfer,
		composite_submit_iso_transfer,
		composite_submit_control_transfer,
		composite_abort_control,
		composite_abort_transfers,
		composite_copy_transfer_data,
	},
	{
		USB_API_WINUSBX,
		"WinUSB-like APIs",
		winusbx_driver_names,
		ARRAYSIZE(winusbx_driver_names),
		winusbx_init,
		winusbx_exit,
		winusbx_open,
		winusbx_close,
		winusbx_configure_endpoints,
		winusbx_claim_interface,
		winusbx_set_interface_altsetting,
		winusbx_release_interface,
		winusbx_clear_halt,
		winusbx_reset_device,
		winusbx_submit_bulk_transfer,
		unsupported_submit_iso_transfer,
		winusbx_submit_control_transfer,
		winusbx_abort_control,
		winusbx_abort_transfers,
		winusbx_copy_transfer_data,
	},
	{
		USB_API_HID,
		"HID API",
		hid_driver_names,
		ARRAYSIZE(hid_driver_names),
		hid_init,
		hid_exit,
		hid_open,
		hid_close,
		common_configure_endpoints,
		hid_claim_interface,
		hid_set_interface_altsetting,
		hid_release_interface,
		hid_clear_halt,
		hid_reset_device,
		hid_submit_bulk_transfer,
		unsupported_submit_iso_transfer,
		hid_submit_control_transfer,
		hid_abort_transfers,
		hid_abort_transfers,
		hid_copy_transfer_data,
	},
};


/*
 * WinUSB-like (WinUSB, libusb0/libusbK through libusbk DLL) API functions
 */
#define WinUSBX_Set(fn)										\
	do {											\
		if (native_winusb)								\
			WinUSBX[i].fn = (WinUsb_##fn##_t)GetProcAddress(h, "WinUsb_" #fn);	\
		else										\
			pLibK_GetProcAddress((PVOID *)&WinUSBX[i].fn, i, KUSB_FNID_##fn);	\
	} while (0)

static int winusbx_init(int sub_api, struct libusb_context *ctx)
{
	HMODULE h;
	bool native_winusb;
	int i;
	KLIB_VERSION LibK_Version;
	LibK_GetProcAddress_t pLibK_GetProcAddress = NULL;
	LibK_GetVersion_t pLibK_GetVersion;

	h = LoadLibraryA("libusbK");

	if (h == NULL) {
		usbi_info(ctx, "libusbK DLL is not available, will use native WinUSB");
		h = LoadLibraryA("WinUSB");

		if (h == NULL) {
			usbi_warn(ctx, "WinUSB DLL is not available either, "
				"you will not be able to access devices outside of enumeration");
			return LIBUSB_ERROR_NOT_FOUND;
		}
	} else {
		usbi_dbg("using libusbK DLL for universal access");
		pLibK_GetVersion = (LibK_GetVersion_t)GetProcAddress(h, "LibK_GetVersion");
		if (pLibK_GetVersion != NULL) {
			pLibK_GetVersion(&LibK_Version);
			usbi_dbg("libusbK version: %d.%d.%d.%d", LibK_Version.Major, LibK_Version.Minor,
				LibK_Version.Micro, LibK_Version.Nano);
		}
		pLibK_GetProcAddress = (LibK_GetProcAddress_t)GetProcAddress(h, "LibK_GetProcAddress");
		if (pLibK_GetProcAddress == NULL) {
			usbi_err(ctx, "LibK_GetProcAddress() not found in libusbK DLL");
			FreeLibrary(h);
			return LIBUSB_ERROR_NOT_FOUND;
		}
	}

	native_winusb = (pLibK_GetProcAddress == NULL);
	for (i = SUB_API_LIBUSBK; i < SUB_API_MAX; i++) {
		WinUSBX_Set(AbortPipe);
		WinUSBX_Set(ControlTransfer);
		WinUSBX_Set(FlushPipe);
		WinUSBX_Set(Free);
		WinUSBX_Set(GetAssociatedInterface);
		WinUSBX_Set(GetCurrentAlternateSetting);
		WinUSBX_Set(GetDescriptor);
		WinUSBX_Set(GetOverlappedResult);
		WinUSBX_Set(GetPipePolicy);
		WinUSBX_Set(GetPowerPolicy);
		WinUSBX_Set(Initialize);
		WinUSBX_Set(QueryDeviceInformation);
		WinUSBX_Set(QueryInterfaceSettings);
		WinUSBX_Set(QueryPipe);
		WinUSBX_Set(ReadPipe);
		WinUSBX_Set(ResetPipe);
		WinUSBX_Set(SetCurrentAlternateSetting);
		WinUSBX_Set(SetPipePolicy);
		WinUSBX_Set(SetPowerPolicy);
		WinUSBX_Set(WritePipe);
		if (!native_winusb)
			WinUSBX_Set(ResetDevice);

		if (WinUSBX[i].Initialize != NULL) {
			WinUSBX[i].initialized = true;
			usbi_dbg("initalized sub API %s", sub_api_name[i]);
		} else {
			usbi_warn(ctx, "Failed to initalize sub API %s", sub_api_name[i]);
			WinUSBX[i].initialized = false;
		}
	}

	WinUSBX_handle = h;
	return LIBUSB_SUCCESS;
}

static int winusbx_exit(int sub_api)
{
	if (WinUSBX_handle != NULL) {
		FreeLibrary(WinUSBX_handle);
		WinUSBX_handle = NULL;

		/* Reset the WinUSBX API structures */
		memset(&WinUSBX, 0, sizeof(WinUSBX));
	}

	return LIBUSB_SUCCESS;
}

// NB: open and close must ensure that they only handle interface of
// the right API type, as these functions can be called wholesale from
// composite_open(), with interfaces belonging to different APIs
static int winusbx_open(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);

	HANDLE file_handle;
	int i;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	// WinUSB requires a separate handle for each interface
	for (i = 0; i < USB_MAXINTERFACES; i++) {
		if ((priv->usb_interface[i].path != NULL)
				&& (priv->usb_interface[i].apib->id == USB_API_WINUSBX)) {
			file_handle = CreateFileA(priv->usb_interface[i].path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
				NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
			if (file_handle == INVALID_HANDLE_VALUE) {
				usbi_err(ctx, "could not open device %s (interface %d): %s", priv->usb_interface[i].path, i, windows_error_str(0));
				switch(GetLastError()) {
				case ERROR_FILE_NOT_FOUND: // The device was disconnected
					return LIBUSB_ERROR_NO_DEVICE;
				case ERROR_ACCESS_DENIED:
					return LIBUSB_ERROR_ACCESS;
				default:
					return LIBUSB_ERROR_IO;
				}
			}
			handle_priv->interface_handle[i].dev_handle = file_handle;
		}
	}

	return LIBUSB_SUCCESS;
}

static void winusbx_close(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	HANDLE handle;
	int i;

	if (sub_api == SUB_API_NOTSET)
		sub_api = priv->sub_api;

	if (!WinUSBX[sub_api].initialized)
		return;

	if (priv->apib->id == USB_API_COMPOSITE) {
		// If this is a composite device, just free and close all WinUSB-like
		// interfaces directly (each is independent and not associated with another)
		for (i = 0; i < USB_MAXINTERFACES; i++) {
			if (priv->usb_interface[i].apib->id == USB_API_WINUSBX) {
				handle = handle_priv->interface_handle[i].api_handle;
				if (HANDLE_VALID(handle))
					WinUSBX[sub_api].Free(handle);

				handle = handle_priv->interface_handle[i].dev_handle;
				if (HANDLE_VALID(handle))
					CloseHandle(handle);
			}
		}
	}
	else {
		// If this is a WinUSB device, free all interfaces above interface 0,
		// then free and close interface 0 last
		for (i = 1; i < USB_MAXINTERFACES; i++) {
			handle = handle_priv->interface_handle[i].api_handle;
			if (HANDLE_VALID(handle))
				WinUSBX[sub_api].Free(handle);
		}
		handle = handle_priv->interface_handle[0].api_handle;
		if (HANDLE_VALID(handle))
			WinUSBX[sub_api].Free(handle);

		handle = handle_priv->interface_handle[0].dev_handle;
		if (HANDLE_VALID(handle))
			CloseHandle(handle);
	}
}

static int winusbx_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	HANDLE winusb_handle = handle_priv->interface_handle[iface].api_handle;
	UCHAR policy;
	ULONG timeout = 0;
	uint8_t endpoint_address;
	int i;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	// With handle and enpoints set (in parent), we can setup the default pipe properties
	// see http://download.microsoft.com/download/D/1/D/D1DD7745-426B-4CC3-A269-ABBBE427C0EF/DVC-T705_DDC08.pptx
	for (i = -1; i < priv->usb_interface[iface].nb_endpoints; i++) {
		endpoint_address = (i == -1) ? 0 : priv->usb_interface[iface].endpoint[i];
		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
			PIPE_TRANSFER_TIMEOUT, sizeof(ULONG), &timeout))
			usbi_dbg("failed to set PIPE_TRANSFER_TIMEOUT for control endpoint %02X", endpoint_address);

		if ((i == -1) || (sub_api == SUB_API_LIBUSB0))
			continue; // Other policies don't apply to control endpoint or libusb0

		policy = false;
		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
			SHORT_PACKET_TERMINATE, sizeof(UCHAR), &policy))
			usbi_dbg("failed to disable SHORT_PACKET_TERMINATE for endpoint %02X", endpoint_address);

		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
			IGNORE_SHORT_PACKETS, sizeof(UCHAR), &policy))
			usbi_dbg("failed to disable IGNORE_SHORT_PACKETS for endpoint %02X", endpoint_address);

		policy = true;
		/* ALLOW_PARTIAL_READS must be enabled due to likely libusbK bug. See:
		   https://sourceforge.net/mailarchive/message.php?msg_id=29736015 */
		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
			ALLOW_PARTIAL_READS, sizeof(UCHAR), &policy))
			usbi_dbg("failed to enable ALLOW_PARTIAL_READS for endpoint %02X", endpoint_address);

		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
			AUTO_CLEAR_STALL, sizeof(UCHAR), &policy))
			usbi_dbg("failed to enable AUTO_CLEAR_STALL for endpoint %02X", endpoint_address);
	}

	return LIBUSB_SUCCESS;
}

static int winusbx_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	bool is_using_usbccgp = (priv->apib->id == USB_API_COMPOSITE);
	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
	HDEVINFO dev_info = INVALID_HANDLE_VALUE;
	SP_DEVINFO_DATA dev_info_data;
	char *dev_path_no_guid = NULL;
	char filter_path[] = "\\\\.\\libusb0-0000";
	bool found_filter = false;
	HANDLE file_handle, winusb_handle;
	DWORD err;
	int i;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	// If the device is composite, but using the default Windows composite parent driver (usbccgp)
	// or if it's the first WinUSB-like interface, we get a handle through Initialize().
	if ((is_using_usbccgp) || (iface == 0)) {
		// composite device (independent interfaces) or interface 0
		file_handle = handle_priv->interface_handle[iface].dev_handle;
		if (!HANDLE_VALID(file_handle))
			return LIBUSB_ERROR_NOT_FOUND;

		if (!WinUSBX[sub_api].Initialize(file_handle, &winusb_handle)) {
			handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
			err = GetLastError();
			switch(err) {
			case ERROR_BAD_COMMAND:
				// The device was disconnected
				usbi_err(ctx, "could not access interface %d: %s", iface, windows_error_str(0));
				return LIBUSB_ERROR_NO_DEVICE;
			default:
				// it may be that we're using the libusb0 filter driver.
				// TODO: can we move this whole business into the K/0 DLL?
				for (i = 0; ; i++) {
					safe_free(dev_interface_details);
					safe_free(dev_path_no_guid);
					dev_interface_details = get_interface_details_filter(ctx, &dev_info, &dev_info_data, &GUID_DEVINTERFACE_LIBUSB0_FILTER, i, filter_path);
					if ((found_filter) || (dev_interface_details == NULL))
						break;

					// ignore GUID part
					dev_path_no_guid = sanitize_path(strtok(dev_interface_details->DevicePath, "{"));
					if (safe_strncmp(dev_path_no_guid, priv->usb_interface[iface].path, safe_strlen(dev_path_no_guid)) == 0) {
						file_handle = CreateFileA(filter_path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
							NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
						if (file_handle == INVALID_HANDLE_VALUE) {
							usbi_err(ctx, "could not open device %s: %s", filter_path, windows_error_str(0));
						} else {
							WinUSBX[sub_api].Free(winusb_handle);
							if (WinUSBX[sub_api].Initialize(file_handle, &winusb_handle))
								found_filter = true;
							else
								usbi_err(ctx, "could not initialize filter driver for %s", filter_path);
						}
					}
				}
				if (!found_filter) {
					usbi_err(ctx, "could not access interface %d: %s", iface, windows_error_str(err));
					return LIBUSB_ERROR_ACCESS;
				}
			}
		}
		handle_priv->interface_handle[iface].api_handle = winusb_handle;
	} else {
		// For all other interfaces, use GetAssociatedInterface()
		winusb_handle = handle_priv->interface_handle[0].api_handle;
		// It is a requirement for multiple interface devices on Windows that, to you
		// must first claim the first interface before you claim the others
		if (!HANDLE_VALID(winusb_handle)) {
			file_handle = handle_priv->interface_handle[0].dev_handle;
			if (WinUSBX[sub_api].Initialize(file_handle, &winusb_handle)) {
				handle_priv->interface_handle[0].api_handle = winusb_handle;
				usbi_warn(ctx, "auto-claimed interface 0 (required to claim %d with WinUSB)", iface);
			} else {
				usbi_warn(ctx, "failed to auto-claim interface 0 (required to claim %d with WinUSB): %s", iface, windows_error_str(0));
				return LIBUSB_ERROR_ACCESS;
			}
		}
		if (!WinUSBX[sub_api].GetAssociatedInterface(winusb_handle, (UCHAR)(iface - 1),
			&handle_priv->interface_handle[iface].api_handle)) {
			handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
			switch(GetLastError()) {
			case ERROR_NO_MORE_ITEMS:   // invalid iface
				return LIBUSB_ERROR_NOT_FOUND;
			case ERROR_BAD_COMMAND:     // The device was disconnected
				return LIBUSB_ERROR_NO_DEVICE;
			case ERROR_ALREADY_EXISTS:  // already claimed
				return LIBUSB_ERROR_BUSY;
			default:
				usbi_err(ctx, "could not claim interface %d: %s", iface, windows_error_str(0));
				return LIBUSB_ERROR_ACCESS;
			}
		}
	}
	usbi_dbg("claimed interface %d", iface);
	handle_priv->active_interface = iface;

	return LIBUSB_SUCCESS;
}

static int winusbx_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	HANDLE winusb_handle;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	winusb_handle = handle_priv->interface_handle[iface].api_handle;
	if (!HANDLE_VALID(winusb_handle))
		return LIBUSB_ERROR_NOT_FOUND;

	WinUSBX[sub_api].Free(winusb_handle);
	handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;

	return LIBUSB_SUCCESS;
}

/*
 * Return the first valid interface (of the same API type), for control transfers
 */
static int get_valid_interface(struct libusb_device_handle *dev_handle, int api_id)
{
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	int i;

	if ((api_id < USB_API_WINUSBX) || (api_id > USB_API_HID)) {
		usbi_dbg("unsupported API ID");
		return -1;
	}

	for (i = 0; i < USB_MAXINTERFACES; i++) {
		if (HANDLE_VALID(handle_priv->interface_handle[i].dev_handle)
				&& HANDLE_VALID(handle_priv->interface_handle[i].api_handle)
				&& (priv->usb_interface[i].apib->id == api_id))
			return i;
	}

	return -1;
}

/*
 * Lookup interface by endpoint address. -1 if not found
 */
static int interface_by_endpoint(struct windows_device_priv *priv,
	struct windows_device_handle_priv *handle_priv, uint8_t endpoint_address)
{
	int i, j;

	for (i = 0; i < USB_MAXINTERFACES; i++) {
		if (!HANDLE_VALID(handle_priv->interface_handle[i].api_handle))
			continue;
		if (priv->usb_interface[i].endpoint == NULL)
			continue;
		for (j = 0; j < priv->usb_interface[i].nb_endpoints; j++) {
			if (priv->usb_interface[i].endpoint[j] == endpoint_address)
				return i;
		}
	}

	return -1;
}

static int winusbx_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *)transfer->buffer;
	ULONG size;
	HANDLE winusb_handle;
	int current_interface;
	struct winfd wfd;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	transfer_priv->pollable_fd = INVALID_WINFD;
	size = transfer->length - LIBUSB_CONTROL_SETUP_SIZE;

	// Windows places upper limits on the control transfer size
	// See: https://msdn.microsoft.com/en-us/library/windows/hardware/ff538112.aspx
	if (size > MAX_CTRL_BUFFER_LENGTH)
		return LIBUSB_ERROR_INVALID_PARAM;

	current_interface = get_valid_interface(transfer->dev_handle, USB_API_WINUSBX);
	if (current_interface < 0) {
		if (auto_claim(transfer, &current_interface, USB_API_WINUSBX) != LIBUSB_SUCCESS)
			return LIBUSB_ERROR_NOT_FOUND;
	}

	usbi_dbg("will use interface %d", current_interface);
	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;

	wfd = usbi_create_fd(winusb_handle, RW_READ, NULL, NULL);
	// Always use the handle returned from usbi_create_fd (wfd.handle)
	if (wfd.fd < 0)
		return LIBUSB_ERROR_NO_MEM;

	// Sending of set configuration control requests from WinUSB creates issues
	if (((setup->request_type & (0x03 << 5)) == LIBUSB_REQUEST_TYPE_STANDARD)
			&& (setup->request == LIBUSB_REQUEST_SET_CONFIGURATION)) {
		if (setup->value != priv->active_config) {
			usbi_warn(ctx, "cannot set configuration other than the default one");
			usbi_free_fd(&wfd);
			return LIBUSB_ERROR_INVALID_PARAM;
		}
		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
		wfd.overlapped->InternalHigh = 0;
	} else {
		if (!WinUSBX[sub_api].ControlTransfer(wfd.handle, *setup, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, size, NULL, wfd.overlapped)) {
			if (GetLastError() != ERROR_IO_PENDING) {
				usbi_warn(ctx, "ControlTransfer failed: %s", windows_error_str(0));
				usbi_free_fd(&wfd);
				return LIBUSB_ERROR_IO;
			}
		} else {
			wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
			wfd.overlapped->InternalHigh = (DWORD)size;
		}
	}

	// Use priv_transfer to store data needed for async polling
	transfer_priv->pollable_fd = wfd;
	transfer_priv->interface_number = (uint8_t)current_interface;

	return LIBUSB_SUCCESS;
}

static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	HANDLE winusb_handle;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	if (altsetting > 255)
		return LIBUSB_ERROR_INVALID_PARAM;

	winusb_handle = handle_priv->interface_handle[iface].api_handle;
	if (!HANDLE_VALID(winusb_handle)) {
		usbi_err(ctx, "interface must be claimed first");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	if (!WinUSBX[sub_api].SetCurrentAlternateSetting(winusb_handle, (UCHAR)altsetting)) {
		usbi_err(ctx, "SetCurrentAlternateSetting failed: %s", windows_error_str(0));
		return LIBUSB_ERROR_IO;
	}

	return LIBUSB_SUCCESS;
}

static int winusbx_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	HANDLE winusb_handle;
	bool ret;
	int current_interface;
	struct winfd wfd;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	transfer_priv->pollable_fd = INVALID_WINFD;

	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
	if (current_interface < 0) {
		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	usbi_dbg("matched endpoint %02X with interface %d", transfer->endpoint, current_interface);

	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;

	wfd = usbi_create_fd(winusb_handle, IS_XFERIN(transfer) ? RW_READ : RW_WRITE, NULL, NULL);
	// Always use the handle returned from usbi_create_fd (wfd.handle)
	if (wfd.fd < 0)
		return LIBUSB_ERROR_NO_MEM;

	if (IS_XFERIN(transfer)) {
		usbi_dbg("reading %d bytes", transfer->length);
		ret = WinUSBX[sub_api].ReadPipe(wfd.handle, transfer->endpoint, transfer->buffer, transfer->length, NULL, wfd.overlapped);
	} else {
		usbi_dbg("writing %d bytes", transfer->length);
		ret = WinUSBX[sub_api].WritePipe(wfd.handle, transfer->endpoint, transfer->buffer, transfer->length, NULL, wfd.overlapped);
	}

	if (!ret) {
		if (GetLastError() != ERROR_IO_PENDING) {
			usbi_err(ctx, "ReadPipe/WritePipe failed: %s", windows_error_str(0));
			usbi_free_fd(&wfd);
			return LIBUSB_ERROR_IO;
		}
	} else {
		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
		wfd.overlapped->InternalHigh = (DWORD)transfer->length;
	}

	transfer_priv->pollable_fd = wfd;
	transfer_priv->interface_number = (uint8_t)current_interface;

	return LIBUSB_SUCCESS;
}

static int winusbx_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	HANDLE winusb_handle;
	int current_interface;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
	if (current_interface < 0) {
		usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	usbi_dbg("matched endpoint %02X with interface %d", endpoint, current_interface);
	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;

	if (!WinUSBX[sub_api].ResetPipe(winusb_handle, endpoint)) {
		usbi_err(ctx, "ResetPipe failed: %s", windows_error_str(0));
		return LIBUSB_ERROR_NO_DEVICE;
	}

	return LIBUSB_SUCCESS;
}

/*
 * from http://www.winvistatips.com/winusb-bugchecks-t335323.html (confirmed
 * through testing as well):
 * "You can not call WinUsb_AbortPipe on control pipe. You can possibly cancel
 * the control transfer using CancelIo"
 */
static int winusbx_abort_control(int sub_api, struct usbi_transfer *itransfer)
{
	// Cancelling of the I/O is done in the parent
	return LIBUSB_SUCCESS;
}

static int winusbx_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	HANDLE winusb_handle;
	int current_interface;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	current_interface = transfer_priv->interface_number;
	if ((current_interface < 0) || (current_interface >= USB_MAXINTERFACES)) {
		usbi_err(ctx, "program assertion failed: invalid interface_number");
		return LIBUSB_ERROR_NOT_FOUND;
	}
	usbi_dbg("will use interface %d", current_interface);

	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;

	if (!WinUSBX[sub_api].AbortPipe(winusb_handle, transfer->endpoint)) {
		usbi_err(ctx, "AbortPipe failed: %s", windows_error_str(0));
		return LIBUSB_ERROR_NO_DEVICE;
	}

	return LIBUSB_SUCCESS;
}

/*
 * from the "How to Use WinUSB to Communicate with a USB Device" Microsoft white paper
 * (http://www.microsoft.com/whdc/connect/usb/winusb_howto.mspx):
 * "WinUSB does not support host-initiated reset port and cycle port operations" and
 * IOCTL_INTERNAL_USB_CYCLE_PORT is only available in kernel mode and the
 * IOCTL_USB_HUB_CYCLE_PORT ioctl was removed from Vista => the best we can do is
 * cycle the pipes (and even then, the control pipe can not be reset using WinUSB)
 */
// TODO: (post hotplug): see if we can force eject the device and redetect it (reuse hotplug?)
static int winusbx_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	struct winfd wfd;
	HANDLE winusb_handle;
	int i, j;

	CHECK_WINUSBX_AVAILABLE(sub_api);

	// Reset any available pipe (except control)
	for (i = 0; i < USB_MAXINTERFACES; i++) {
		winusb_handle = handle_priv->interface_handle[i].api_handle;
		for (wfd = handle_to_winfd(winusb_handle); wfd.fd > 0; ) {
			// Cancel any pollable I/O
			usbi_remove_pollfd(ctx, wfd.fd);
			usbi_free_fd(&wfd);
			wfd = handle_to_winfd(winusb_handle);
		}

		if (HANDLE_VALID(winusb_handle)) {
			for (j = 0; j < priv->usb_interface[i].nb_endpoints; j++) {
				usbi_dbg("resetting ep %02X", priv->usb_interface[i].endpoint[j]);
				if (!WinUSBX[sub_api].AbortPipe(winusb_handle, priv->usb_interface[i].endpoint[j]))
					usbi_err(ctx, "AbortPipe (pipe address %02X) failed: %s",
						priv->usb_interface[i].endpoint[j], windows_error_str(0));

				// FlushPipe seems to fail on OUT pipes
				if (IS_EPIN(priv->usb_interface[i].endpoint[j])
						&& (!WinUSBX[sub_api].FlushPipe(winusb_handle, priv->usb_interface[i].endpoint[j])))
					usbi_err(ctx, "FlushPipe (pipe address %02X) failed: %s",
						priv->usb_interface[i].endpoint[j], windows_error_str(0));

				if (!WinUSBX[sub_api].ResetPipe(winusb_handle, priv->usb_interface[i].endpoint[j]))
					usbi_err(ctx, "ResetPipe (pipe address %02X) failed: %s",
						priv->usb_interface[i].endpoint[j], windows_error_str(0));
			}
		}
	}

	// libusbK & libusb0 have the ability to issue an actual device reset
	if (WinUSBX[sub_api].ResetDevice != NULL) {
		winusb_handle = handle_priv->interface_handle[0].api_handle;
		if (HANDLE_VALID(winusb_handle))
			WinUSBX[sub_api].ResetDevice(winusb_handle);
	}

	return LIBUSB_SUCCESS;
}

static int winusbx_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
{
	itransfer->transferred += io_size;
	return LIBUSB_TRANSFER_COMPLETED;
}

/*
 * Internal HID Support functions (from libusb-win32)
 * Note that functions that complete data transfer synchronously must return
 * LIBUSB_COMPLETED instead of LIBUSB_SUCCESS
 */
static int _hid_get_hid_descriptor(struct hid_device_priv *dev, void *data, size_t *size);
static int _hid_get_report_descriptor(struct hid_device_priv *dev, void *data, size_t *size);

static int _hid_wcslen(WCHAR *str)
{
	int i = 0;

	while (str[i] && (str[i] != 0x409))
		i++;

	return i;
}

static int _hid_get_device_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
{
	struct libusb_device_descriptor d;

	d.bLength = LIBUSB_DT_DEVICE_SIZE;
	d.bDescriptorType = LIBUSB_DT_DEVICE;
	d.bcdUSB = 0x0200; /* 2.00 */
	d.bDeviceClass = 0;
	d.bDeviceSubClass = 0;
	d.bDeviceProtocol = 0;
	d.bMaxPacketSize0 = 64; /* fix this! */
	d.idVendor = (uint16_t)dev->vid;
	d.idProduct = (uint16_t)dev->pid;
	d.bcdDevice = 0x0100;
	d.iManufacturer = dev->string_index[0];
	d.iProduct = dev->string_index[1];
	d.iSerialNumber = dev->string_index[2];
	d.bNumConfigurations = 1;

	if (*size > LIBUSB_DT_DEVICE_SIZE)
		*size = LIBUSB_DT_DEVICE_SIZE;
	memcpy(data, &d, *size);

	return LIBUSB_COMPLETED;
}

static int _hid_get_config_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
{
	char num_endpoints = 0;
	size_t config_total_len = 0;
	char tmp[HID_MAX_CONFIG_DESC_SIZE];
	struct libusb_config_descriptor *cd;
	struct libusb_interface_descriptor *id;
	struct libusb_hid_descriptor *hd;
	struct libusb_endpoint_descriptor *ed;
	size_t tmp_size;

	if (dev->input_report_size)
		num_endpoints++;
	if (dev->output_report_size)
		num_endpoints++;

	config_total_len = LIBUSB_DT_CONFIG_SIZE + LIBUSB_DT_INTERFACE_SIZE
		+ LIBUSB_DT_HID_SIZE + num_endpoints * LIBUSB_DT_ENDPOINT_SIZE;

	cd = (struct libusb_config_descriptor *)tmp;
	id = (struct libusb_interface_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE);
	hd = (struct libusb_hid_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE
		+ LIBUSB_DT_INTERFACE_SIZE);
	ed = (struct libusb_endpoint_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE
		+ LIBUSB_DT_INTERFACE_SIZE
		+ LIBUSB_DT_HID_SIZE);

	cd->bLength = LIBUSB_DT_CONFIG_SIZE;
	cd->bDescriptorType = LIBUSB_DT_CONFIG;
	cd->wTotalLength = (uint16_t)config_total_len;
	cd->bNumInterfaces = 1;
	cd->bConfigurationValue = 1;
	cd->iConfiguration = 0;
	cd->bmAttributes = 1 << 7; /* bus powered */
	cd->MaxPower = 50;

	id->bLength = LIBUSB_DT_INTERFACE_SIZE;
	id->bDescriptorType = LIBUSB_DT_INTERFACE;
	id->bInterfaceNumber = 0;
	id->bAlternateSetting = 0;
	id->bNumEndpoints = num_endpoints;
	id->bInterfaceClass = 3;
	id->bInterfaceSubClass = 0;
	id->bInterfaceProtocol = 0;
	id->iInterface = 0;

	tmp_size = LIBUSB_DT_HID_SIZE;
	_hid_get_hid_descriptor(dev, hd, &tmp_size);

	if (dev->input_report_size) {
		ed->bLength = LIBUSB_DT_ENDPOINT_SIZE;
		ed->bDescriptorType = LIBUSB_DT_ENDPOINT;
		ed->bEndpointAddress = HID_IN_EP;
		ed->bmAttributes = 3;
		ed->wMaxPacketSize = dev->input_report_size - 1;
		ed->bInterval = 10;
		ed = (struct libusb_endpoint_descriptor *)((char *)ed + LIBUSB_DT_ENDPOINT_SIZE);
	}

	if (dev->output_report_size) {
		ed->bLength = LIBUSB_DT_ENDPOINT_SIZE;
		ed->bDescriptorType = LIBUSB_DT_ENDPOINT;
		ed->bEndpointAddress = HID_OUT_EP;
		ed->bmAttributes = 3;
		ed->wMaxPacketSize = dev->output_report_size - 1;
		ed->bInterval = 10;
	}

	if (*size > config_total_len)
		*size = config_total_len;
	memcpy(data, tmp, *size);

	return LIBUSB_COMPLETED;
}

static int _hid_get_string_descriptor(struct hid_device_priv *dev, int _index,
	void *data, size_t *size)
{
	void *tmp = NULL;
	size_t tmp_size = 0;
	int i;

	/* language ID, EN-US */
	char string_langid[] = {0x09, 0x04};

	if ((*size < 2) || (*size > 255))
		return LIBUSB_ERROR_OVERFLOW;

	if (_index == 0) {
		tmp = string_langid;
		tmp_size = sizeof(string_langid) + 2;
	} else {
		for (i = 0; i < 3; i++) {
			if (_index == (dev->string_index[i])) {
				tmp = dev->string[i];
				tmp_size = (_hid_wcslen(dev->string[i]) + 1) * sizeof(WCHAR);
				break;
			}
		}

		if (i == 3) // not found
			return LIBUSB_ERROR_INVALID_PARAM;
	}

	if (!tmp_size)
		return LIBUSB_ERROR_INVALID_PARAM;

	if (tmp_size < *size)
		*size = tmp_size;

	// 2 byte header
	((uint8_t *)data)[0] = (uint8_t)*size;
	((uint8_t *)data)[1] = LIBUSB_DT_STRING;
	memcpy((uint8_t *)data + 2, tmp, *size - 2);

	return LIBUSB_COMPLETED;
}

static int _hid_get_hid_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
{
	struct libusb_hid_descriptor d;
	uint8_t tmp[MAX_HID_DESCRIPTOR_SIZE];
	size_t report_len = MAX_HID_DESCRIPTOR_SIZE;

	_hid_get_report_descriptor(dev, tmp, &report_len);

	d.bLength = LIBUSB_DT_HID_SIZE;
	d.bDescriptorType = LIBUSB_DT_HID;
	d.bcdHID = 0x0110; /* 1.10 */
	d.bCountryCode = 0;
	d.bNumDescriptors = 1;
	d.bClassDescriptorType = LIBUSB_DT_REPORT;
	d.wClassDescriptorLength = (uint16_t)report_len;

	if (*size > LIBUSB_DT_HID_SIZE)
		*size = LIBUSB_DT_HID_SIZE;
	memcpy(data, &d, *size);

	return LIBUSB_COMPLETED;
}

static int _hid_get_report_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
{
	uint8_t d[MAX_HID_DESCRIPTOR_SIZE];
	size_t i = 0;

	/* usage page (0xFFA0 == vendor defined) */
	d[i++] = 0x06; d[i++] = 0xA0; d[i++] = 0xFF;
	/* usage (vendor defined) */
	d[i++] = 0x09; d[i++] = 0x01;
	/* start collection (application) */
	d[i++] = 0xA1; d[i++] = 0x01;
	/* input report */
	if (dev->input_report_size) {
		/* usage (vendor defined) */
		d[i++] = 0x09; d[i++] = 0x01;
		/* logical minimum (0) */
		d[i++] = 0x15; d[i++] = 0x00;
		/* logical maximum (255) */
		d[i++] = 0x25; d[i++] = 0xFF;
		/* report size (8 bits) */
		d[i++] = 0x75; d[i++] = 0x08;
		/* report count */
		d[i++] = 0x95; d[i++] = (uint8_t)dev->input_report_size - 1;
		/* input (data, variable, absolute) */
		d[i++] = 0x81; d[i++] = 0x00;
	}
	/* output report */
	if (dev->output_report_size) {
		/* usage (vendor defined) */
		d[i++] = 0x09; d[i++] = 0x02;
		/* logical minimum (0) */
		d[i++] = 0x15; d[i++] = 0x00;
		/* logical maximum (255) */
		d[i++] = 0x25; d[i++] = 0xFF;
		/* report size (8 bits) */
		d[i++] = 0x75; d[i++] = 0x08;
		/* report count */
		d[i++] = 0x95; d[i++] = (uint8_t)dev->output_report_size - 1;
		/* output (data, variable, absolute) */
		d[i++] = 0x91; d[i++] = 0x00;
	}
	/* feature report */
	if (dev->feature_report_size) {
		/* usage (vendor defined) */
		d[i++] = 0x09; d[i++] = 0x03;
		/* logical minimum (0) */
		d[i++] = 0x15; d[i++] = 0x00;
		/* logical maximum (255) */
		d[i++] = 0x25; d[i++] = 0xFF;
		/* report size (8 bits) */
		d[i++] = 0x75; d[i++] = 0x08;
		/* report count */
		d[i++] = 0x95; d[i++] = (uint8_t)dev->feature_report_size - 1;
		/* feature (data, variable, absolute) */
		d[i++] = 0xb2; d[i++] = 0x02; d[i++] = 0x01;
	}

	/* end collection */
	d[i++] = 0xC0;

	if (*size > i)
		*size = i;
	memcpy(data, d, *size);

	return LIBUSB_COMPLETED;
}

static int _hid_get_descriptor(struct hid_device_priv *dev, HANDLE hid_handle, int recipient,
	int type, int _index, void *data, size_t *size)
{
	switch(type) {
	case LIBUSB_DT_DEVICE:
		usbi_dbg("LIBUSB_DT_DEVICE");
		return _hid_get_device_descriptor(dev, data, size);
	case LIBUSB_DT_CONFIG:
		usbi_dbg("LIBUSB_DT_CONFIG");
		if (!_index)
			return _hid_get_config_descriptor(dev, data, size);
		return LIBUSB_ERROR_INVALID_PARAM;
	case LIBUSB_DT_STRING:
		usbi_dbg("LIBUSB_DT_STRING");
		return _hid_get_string_descriptor(dev, _index, data, size);
	case LIBUSB_DT_HID:
		usbi_dbg("LIBUSB_DT_HID");
		if (!_index)
			return _hid_get_hid_descriptor(dev, data, size);
		return LIBUSB_ERROR_INVALID_PARAM;
	case LIBUSB_DT_REPORT:
		usbi_dbg("LIBUSB_DT_REPORT");
		if (!_index)
			return _hid_get_report_descriptor(dev, data, size);
		return LIBUSB_ERROR_INVALID_PARAM;
	case LIBUSB_DT_PHYSICAL:
		usbi_dbg("LIBUSB_DT_PHYSICAL");
		if (HidD_GetPhysicalDescriptor(hid_handle, data, (ULONG)*size))
			return LIBUSB_COMPLETED;
		return LIBUSB_ERROR_OTHER;
	}

	usbi_dbg("unsupported");
	return LIBUSB_ERROR_NOT_SUPPORTED;
}

static int _hid_get_report(struct hid_device_priv *dev, HANDLE hid_handle, int id, void *data,
	struct windows_transfer_priv *tp, size_t *size, OVERLAPPED *overlapped, int report_type)
{
	uint8_t *buf;
	DWORD ioctl_code, read_size, expected_size = (DWORD)*size;
	int r = LIBUSB_SUCCESS;

	if (tp->hid_buffer != NULL)
		usbi_dbg("program assertion failed: hid_buffer is not NULL");

	if ((*size == 0) || (*size > MAX_HID_REPORT_SIZE)) {
		usbi_dbg("invalid size (%u)", *size);
		return LIBUSB_ERROR_INVALID_PARAM;
	}

	switch (report_type) {
	case HID_REPORT_TYPE_INPUT:
		ioctl_code = IOCTL_HID_GET_INPUT_REPORT;
		break;
	case HID_REPORT_TYPE_FEATURE:
		ioctl_code = IOCTL_HID_GET_FEATURE;
		break;
	default:
		usbi_dbg("unknown HID report type %d", report_type);
		return LIBUSB_ERROR_INVALID_PARAM;
	}

	// Add a trailing byte to detect overflows
	buf = calloc(1, expected_size + 1);
	if (buf == NULL)
		return LIBUSB_ERROR_NO_MEM;

	buf[0] = (uint8_t)id; // Must be set always
	usbi_dbg("report ID: 0x%02X", buf[0]);

	tp->hid_expected_size = expected_size;
	read_size = expected_size;

	// NB: The size returned by DeviceIoControl doesn't include report IDs when not in use (0)
	if (!DeviceIoControl(hid_handle, ioctl_code, buf, expected_size + 1,
		buf, expected_size + 1, &read_size, overlapped)) {
		if (GetLastError() != ERROR_IO_PENDING) {
			usbi_dbg("Failed to Read HID Report: %s", windows_error_str(0));
			safe_free(buf);
			return LIBUSB_ERROR_IO;
		}
		// Asynchronous wait
		tp->hid_buffer = buf;
		tp->hid_dest = data; // copy dest, as not necessarily the start of the transfer buffer
		return LIBUSB_SUCCESS;
	}

	// Transfer completed synchronously => copy and discard extra buffer
	if (read_size == 0) {
		usbi_warn(NULL, "program assertion failed - read completed synchronously, but no data was read");
		*size = 0;
	} else {
		if (buf[0] != id)
			usbi_warn(NULL, "mismatched report ID (data is %02X, parameter is %02X)", buf[0], id);

		if ((size_t)read_size > expected_size) {
			r = LIBUSB_ERROR_OVERFLOW;
			usbi_dbg("OVERFLOW!");
		} else {
			r = LIBUSB_COMPLETED;
		}

		*size = MIN((size_t)read_size, *size);
		if (id == 0)
			memcpy(data, buf + 1, *size); // Discard report ID
		else
			memcpy(data, buf, *size);
	}

	safe_free(buf);
	return r;
}

static int _hid_set_report(struct hid_device_priv *dev, HANDLE hid_handle, int id, void *data,
	struct windows_transfer_priv *tp, size_t *size, OVERLAPPED *overlapped, int report_type)
{
	uint8_t *buf = NULL;
	DWORD ioctl_code, write_size = (DWORD)*size;

	if (tp->hid_buffer != NULL)
		usbi_dbg("program assertion failed: hid_buffer is not NULL");

	if ((*size == 0) || (*size > MAX_HID_REPORT_SIZE)) {
		usbi_dbg("invalid size (%u)", *size);
		return LIBUSB_ERROR_INVALID_PARAM;
	}

	switch (report_type) {
	case HID_REPORT_TYPE_OUTPUT:
		ioctl_code = IOCTL_HID_SET_OUTPUT_REPORT;
		break;
	case HID_REPORT_TYPE_FEATURE:
		ioctl_code = IOCTL_HID_SET_FEATURE;
		break;
	default:
		usbi_dbg("unknown HID report type %d", report_type);
		return LIBUSB_ERROR_INVALID_PARAM;
	}

	usbi_dbg("report ID: 0x%02X", id);
	// When report IDs are not used (i.e. when id == 0), we must add
	// a null report ID. Otherwise, we just use original data buffer
	if (id == 0)
		write_size++;

	buf = malloc(write_size);
	if (buf == NULL)
		return LIBUSB_ERROR_NO_MEM;

	if (id == 0) {
		buf[0] = 0;
		memcpy(buf + 1, data, *size);
	} else {
		// This seems like a waste, but if we don't duplicate the
		// data, we'll get issues when freeing hid_buffer
		memcpy(buf, data, *size);
		if (buf[0] != id)
			usbi_warn(NULL, "mismatched report ID (data is %02X, parameter is %02X)", buf[0], id);
	}

	// NB: The size returned by DeviceIoControl doesn't include report IDs when not in use (0)
	if (!DeviceIoControl(hid_handle, ioctl_code, buf, write_size,
		buf, write_size, &write_size, overlapped)) {
		if (GetLastError() != ERROR_IO_PENDING) {
			usbi_dbg("Failed to Write HID Output Report: %s", windows_error_str(0));
			safe_free(buf);
			return LIBUSB_ERROR_IO;
		}
		tp->hid_buffer = buf;
		tp->hid_dest = NULL;
		return LIBUSB_SUCCESS;
	}

	// Transfer completed synchronously
	*size = write_size;
	if (write_size == 0)
		usbi_dbg("program assertion failed - write completed synchronously, but no data was written");

	safe_free(buf);
	return LIBUSB_COMPLETED;
}

static int _hid_class_request(struct hid_device_priv *dev, HANDLE hid_handle, int request_type,
	int request, int value, int _index, void *data, struct windows_transfer_priv *tp,
	size_t *size, OVERLAPPED *overlapped)
{
	int report_type = (value >> 8) & 0xFF;
	int report_id = value & 0xFF;

	if ((LIBUSB_REQ_RECIPIENT(request_type) != LIBUSB_RECIPIENT_INTERFACE)
			&& (LIBUSB_REQ_RECIPIENT(request_type) != LIBUSB_RECIPIENT_DEVICE))
		return LIBUSB_ERROR_INVALID_PARAM;

	if (LIBUSB_REQ_OUT(request_type) && request == HID_REQ_SET_REPORT)
		return _hid_set_report(dev, hid_handle, report_id, data, tp, size, overlapped, report_type);

	if (LIBUSB_REQ_IN(request_type) && request == HID_REQ_GET_REPORT)
		return _hid_get_report(dev, hid_handle, report_id, data, tp, size, overlapped, report_type);

	return LIBUSB_ERROR_INVALID_PARAM;
}


/*
 * HID API functions
 */
static int hid_init(int sub_api, struct libusb_context *ctx)
{
	DLL_GET_HANDLE(hid);
	DLL_LOAD_FUNC(hid, HidD_GetAttributes, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetHidGuid, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetPreparsedData, TRUE);
	DLL_LOAD_FUNC(hid, HidD_FreePreparsedData, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetManufacturerString, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetProductString, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetSerialNumberString, TRUE);
	DLL_LOAD_FUNC(hid, HidP_GetCaps, TRUE);
	DLL_LOAD_FUNC(hid, HidD_SetNumInputBuffers, TRUE);
	DLL_LOAD_FUNC(hid, HidD_SetFeature, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetFeature, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetPhysicalDescriptor, TRUE);
	DLL_LOAD_FUNC(hid, HidD_GetInputReport, FALSE);
	DLL_LOAD_FUNC(hid, HidD_SetOutputReport, FALSE);
	DLL_LOAD_FUNC(hid, HidD_FlushQueue, TRUE);
	DLL_LOAD_FUNC(hid, HidP_GetValueCaps, TRUE);

	api_hid_available = true;
	return LIBUSB_SUCCESS;
}

static int hid_exit(int sub_api)
{
	DLL_FREE_HANDLE(hid);

	return LIBUSB_SUCCESS;
}

// NB: open and close must ensure that they only handle interface of
// the right API type, as these functions can be called wholesale from
// composite_open(), with interfaces belonging to different APIs
static int hid_open(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	HIDD_ATTRIBUTES hid_attributes;
	PHIDP_PREPARSED_DATA preparsed_data = NULL;
	HIDP_CAPS capabilities;
	HIDP_VALUE_CAPS *value_caps;
	HANDLE hid_handle = INVALID_HANDLE_VALUE;
	int i, j;
	// report IDs handling
	ULONG size[3];
	int nb_ids[2]; // zero and nonzero report IDs
#if defined(ENABLE_LOGGING)
	const char *type[3] = {"input", "output", "feature"};
#endif

	CHECK_HID_AVAILABLE;

	if (priv->hid == NULL) {
		usbi_err(ctx, "program assertion failed - private HID structure is unitialized");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	for (i = 0; i < USB_MAXINTERFACES; i++) {
		if ((priv->usb_interface[i].path != NULL)
				&& (priv->usb_interface[i].apib->id == USB_API_HID)) {
			hid_handle = CreateFileA(priv->usb_interface[i].path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
				NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
			/*
			 * http://www.lvr.com/hidfaq.htm: Why do I receive "Access denied" when attempting to access my HID?
			 * "Windows 2000 and later have exclusive read/write access to HIDs that are configured as a system
			 * keyboards or mice. An application can obtain a handle to a system keyboard or mouse by not
			 * requesting READ or WRITE access with CreateFile. Applications can then use HidD_SetFeature and
			 * HidD_GetFeature (if the device supports Feature reports)."
			 */
			if (hid_handle == INVALID_HANDLE_VALUE) {
				usbi_warn(ctx, "could not open HID device in R/W mode (keyboard or mouse?) - trying without");
				hid_handle = CreateFileA(priv->usb_interface[i].path, 0, FILE_SHARE_WRITE | FILE_SHARE_READ,
					NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
				if (hid_handle == INVALID_HANDLE_VALUE) {
					usbi_err(ctx, "could not open device %s (interface %d): %s", priv->path, i, windows_error_str(0));
					switch(GetLastError()) {
					case ERROR_FILE_NOT_FOUND: // The device was disconnected
						return LIBUSB_ERROR_NO_DEVICE;
					case ERROR_ACCESS_DENIED:
						return LIBUSB_ERROR_ACCESS;
					default:
						return LIBUSB_ERROR_IO;
					}
				}
				priv->usb_interface[i].restricted_functionality = true;
			}
			handle_priv->interface_handle[i].api_handle = hid_handle;
		}
	}

	hid_attributes.Size = sizeof(hid_attributes);
	do {
		if (!HidD_GetAttributes(hid_handle, &hid_attributes)) {
			usbi_err(ctx, "could not gain access to HID top collection (HidD_GetAttributes)");
			break;
		}

		priv->hid->vid = hid_attributes.VendorID;
		priv->hid->pid = hid_attributes.ProductID;

		// Set the maximum available input buffer size
		for (i = 32; HidD_SetNumInputBuffers(hid_handle, i); i *= 2);
		usbi_dbg("set maximum input buffer size to %d", i / 2);

		// Get the maximum input and output report size
		if (!HidD_GetPreparsedData(hid_handle, &preparsed_data) || !preparsed_data) {
			usbi_err(ctx, "could not read HID preparsed data (HidD_GetPreparsedData)");
			break;
		}
		if (HidP_GetCaps(preparsed_data, &capabilities) != HIDP_STATUS_SUCCESS) {
			usbi_err(ctx, "could not parse HID capabilities (HidP_GetCaps)");
			break;
		}

		// Find out if interrupt will need report IDs
		size[0] = capabilities.NumberInputValueCaps;
		size[1] = capabilities.NumberOutputValueCaps;
		size[2] = capabilities.NumberFeatureValueCaps;
		for (j = HidP_Input; j <= HidP_Feature; j++) {
			usbi_dbg("%u HID %s report value(s) found", (unsigned int)size[j], type[j]);
			priv->hid->uses_report_ids[j] = false;
			if (size[j] > 0) {
				value_caps = calloc(size[j], sizeof(HIDP_VALUE_CAPS));
				if ((value_caps != NULL)
						&& (HidP_GetValueCaps((HIDP_REPORT_TYPE)j, value_caps, &size[j], preparsed_data) == HIDP_STATUS_SUCCESS)
						&& (size[j] >= 1)) {
					nb_ids[0] = 0;
					nb_ids[1] = 0;
					for (i = 0; i < (int)size[j]; i++) {
						usbi_dbg("  Report ID: 0x%02X", value_caps[i].ReportID);
						if (value_caps[i].ReportID != 0)
							nb_ids[1]++;
						else
							nb_ids[0]++;
					}
					if (nb_ids[1] != 0) {
						if (nb_ids[0] != 0)
							usbi_warn(ctx, "program assertion failed: zero and nonzero report IDs used for %s",
								type[j]);
						priv->hid->uses_report_ids[j] = true;
					}
				} else {
					usbi_warn(ctx, "  could not process %s report IDs", type[j]);
				}
				safe_free(value_caps);
			}
		}

		// Set the report sizes
		priv->hid->input_report_size = capabilities.InputReportByteLength;
		priv->hid->output_report_size = capabilities.OutputReportByteLength;
		priv->hid->feature_report_size = capabilities.FeatureReportByteLength;

		// Fetch string descriptors
		priv->hid->string_index[0] = priv->dev_descriptor.iManufacturer;
		if (priv->hid->string_index[0] != 0)
			HidD_GetManufacturerString(hid_handle, priv->hid->string[0], sizeof(priv->hid->string[0]));
		else
			priv->hid->string[0][0] = 0;

		priv->hid->string_index[1] = priv->dev_descriptor.iProduct;
		if (priv->hid->string_index[1] != 0)
			HidD_GetProductString(hid_handle, priv->hid->string[1], sizeof(priv->hid->string[1]));
		else
			priv->hid->string[1][0] = 0;

		priv->hid->string_index[2] = priv->dev_descriptor.iSerialNumber;
		if (priv->hid->string_index[2] != 0)
			HidD_GetSerialNumberString(hid_handle, priv->hid->string[2], sizeof(priv->hid->string[2]));
		else
			priv->hid->string[2][0] = 0;
	} while(0);

	if (preparsed_data)
		HidD_FreePreparsedData(preparsed_data);

	return LIBUSB_SUCCESS;
}

static void hid_close(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	HANDLE file_handle;
	int i;

	if (!api_hid_available)
		return;

	for (i = 0; i < USB_MAXINTERFACES; i++) {
		if (priv->usb_interface[i].apib->id == USB_API_HID) {
			file_handle = handle_priv->interface_handle[i].api_handle;
			if (HANDLE_VALID(file_handle))
				CloseHandle(file_handle);
		}
	}
}

static int hid_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	CHECK_HID_AVAILABLE;

	// NB: Disconnection detection is not possible in this function
	if (priv->usb_interface[iface].path == NULL)
		return LIBUSB_ERROR_NOT_FOUND; // invalid iface

	// We use dev_handle as a flag for interface claimed
	if (handle_priv->interface_handle[iface].dev_handle == INTERFACE_CLAIMED)
		return LIBUSB_ERROR_BUSY; // already claimed


	handle_priv->interface_handle[iface].dev_handle = INTERFACE_CLAIMED;

	usbi_dbg("claimed interface %d", iface);
	handle_priv->active_interface = iface;

	return LIBUSB_SUCCESS;
}

static int hid_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	CHECK_HID_AVAILABLE;

	if (priv->usb_interface[iface].path == NULL)
		return LIBUSB_ERROR_NOT_FOUND; // invalid iface

	if (handle_priv->interface_handle[iface].dev_handle != INTERFACE_CLAIMED)
		return LIBUSB_ERROR_NOT_FOUND; // invalid iface

	handle_priv->interface_handle[iface].dev_handle = INVALID_HANDLE_VALUE;

	return LIBUSB_SUCCESS;
}

static int hid_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);

	CHECK_HID_AVAILABLE;

	if (altsetting > 255)
		return LIBUSB_ERROR_INVALID_PARAM;

	if (altsetting != 0) {
		usbi_err(ctx, "set interface altsetting not supported for altsetting >0");
		return LIBUSB_ERROR_NOT_SUPPORTED;
	}

	return LIBUSB_SUCCESS;
}

static int hid_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *)transfer->buffer;
	HANDLE hid_handle;
	struct winfd wfd;
	int current_interface, config;
	size_t size;
	int r = LIBUSB_ERROR_INVALID_PARAM;

	CHECK_HID_AVAILABLE;

	transfer_priv->pollable_fd = INVALID_WINFD;
	safe_free(transfer_priv->hid_buffer);
	transfer_priv->hid_dest = NULL;
	size = transfer->length - LIBUSB_CONTROL_SETUP_SIZE;

	if (size > MAX_CTRL_BUFFER_LENGTH)
		return LIBUSB_ERROR_INVALID_PARAM;

	current_interface = get_valid_interface(transfer->dev_handle, USB_API_HID);
	if (current_interface < 0) {
		if (auto_claim(transfer, &current_interface, USB_API_HID) != LIBUSB_SUCCESS)
			return LIBUSB_ERROR_NOT_FOUND;
	}

	usbi_dbg("will use interface %d", current_interface);
	hid_handle = handle_priv->interface_handle[current_interface].api_handle;
	// Always use the handle returned from usbi_create_fd (wfd.handle)
	wfd = usbi_create_fd(hid_handle, RW_READ, NULL, NULL);
	if (wfd.fd < 0)
		return LIBUSB_ERROR_NOT_FOUND;

	switch(LIBUSB_REQ_TYPE(setup->request_type)) {
	case LIBUSB_REQUEST_TYPE_STANDARD:
		switch(setup->request) {
		case LIBUSB_REQUEST_GET_DESCRIPTOR:
			r = _hid_get_descriptor(priv->hid, wfd.handle, LIBUSB_REQ_RECIPIENT(setup->request_type),
				(setup->value >> 8) & 0xFF, setup->value & 0xFF, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, &size);
			break;
		case LIBUSB_REQUEST_GET_CONFIGURATION:
			r = windows_get_configuration(transfer->dev_handle, &config);
			if (r == LIBUSB_SUCCESS) {
				size = 1;
				((uint8_t *)transfer->buffer)[LIBUSB_CONTROL_SETUP_SIZE] = (uint8_t)config;
				r = LIBUSB_COMPLETED;
			}
			break;
		case LIBUSB_REQUEST_SET_CONFIGURATION:
			if (setup->value == priv->active_config) {
				r = LIBUSB_COMPLETED;
			} else {
				usbi_warn(ctx, "cannot set configuration other than the default one");
				r = LIBUSB_ERROR_NOT_SUPPORTED;
			}
			break;
		case LIBUSB_REQUEST_GET_INTERFACE:
			size = 1;
			((uint8_t *)transfer->buffer)[LIBUSB_CONTROL_SETUP_SIZE] = 0;
			r = LIBUSB_COMPLETED;
			break;
		case LIBUSB_REQUEST_SET_INTERFACE:
			r = hid_set_interface_altsetting(0, transfer->dev_handle, setup->index, setup->value);
			if (r == LIBUSB_SUCCESS)
				r = LIBUSB_COMPLETED;
			break;
		default:
			usbi_warn(ctx, "unsupported HID control request");
			r = LIBUSB_ERROR_NOT_SUPPORTED;
			break;
		}
		break;
	case LIBUSB_REQUEST_TYPE_CLASS:
		r = _hid_class_request(priv->hid, wfd.handle, setup->request_type, setup->request, setup->value,
			setup->index, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, transfer_priv,
			&size, wfd.overlapped);
		break;
	default:
		usbi_warn(ctx, "unsupported HID control request");
		r = LIBUSB_ERROR_NOT_SUPPORTED;
		break;
	}

	if (r == LIBUSB_COMPLETED) {
		// Force request to be completed synchronously. Transferred size has been set by previous call
		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
		// http://msdn.microsoft.com/en-us/library/ms684342%28VS.85%29.aspx
		// set InternalHigh to the number of bytes transferred
		wfd.overlapped->InternalHigh = (DWORD)size;
		r = LIBUSB_SUCCESS;
	}

	if (r == LIBUSB_SUCCESS) {
		// Use priv_transfer to store data needed for async polling
		transfer_priv->pollable_fd = wfd;
		transfer_priv->interface_number = (uint8_t)current_interface;
	} else {
		usbi_free_fd(&wfd);
	}

	return r;
}

static int hid_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	struct winfd wfd;
	HANDLE hid_handle;
	bool direction_in, ret;
	int current_interface, length;
	DWORD size;
	int r = LIBUSB_SUCCESS;

	CHECK_HID_AVAILABLE;

	transfer_priv->pollable_fd = INVALID_WINFD;
	transfer_priv->hid_dest = NULL;
	safe_free(transfer_priv->hid_buffer);

	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
	if (current_interface < 0) {
		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	usbi_dbg("matched endpoint %02X with interface %d", transfer->endpoint, current_interface);

	hid_handle = handle_priv->interface_handle[current_interface].api_handle;
	direction_in = transfer->endpoint & LIBUSB_ENDPOINT_IN;

	wfd = usbi_create_fd(hid_handle, direction_in?RW_READ:RW_WRITE, NULL, NULL);
	// Always use the handle returned from usbi_create_fd (wfd.handle)
	if (wfd.fd < 0)
		return LIBUSB_ERROR_NO_MEM;

	// If report IDs are not in use, an extra prefix byte must be added
	if (((direction_in) && (!priv->hid->uses_report_ids[0]))
			|| ((!direction_in) && (!priv->hid->uses_report_ids[1])))
		length = transfer->length + 1;
	else
		length = transfer->length;

	// Add a trailing byte to detect overflows on input
	transfer_priv->hid_buffer = calloc(1, length + 1);
	if (transfer_priv->hid_buffer == NULL)
		return LIBUSB_ERROR_NO_MEM;

	transfer_priv->hid_expected_size = length;

	if (direction_in) {
		transfer_priv->hid_dest = transfer->buffer;
		usbi_dbg("reading %d bytes (report ID: 0x00)", length);
		ret = ReadFile(wfd.handle, transfer_priv->hid_buffer, length + 1, &size, wfd.overlapped);
	} else {
		if (!priv->hid->uses_report_ids[1])
			memcpy(transfer_priv->hid_buffer + 1, transfer->buffer, transfer->length);
		else
			// We could actually do without the calloc and memcpy in this case
			memcpy(transfer_priv->hid_buffer, transfer->buffer, transfer->length);

		usbi_dbg("writing %d bytes (report ID: 0x%02X)", length, transfer_priv->hid_buffer[0]);
		ret = WriteFile(wfd.handle, transfer_priv->hid_buffer, length, &size, wfd.overlapped);
	}

	if (!ret) {
		if (GetLastError() != ERROR_IO_PENDING) {
			usbi_err(ctx, "HID transfer failed: %s", windows_error_str(0));
			usbi_free_fd(&wfd);
			safe_free(transfer_priv->hid_buffer);
			return LIBUSB_ERROR_IO;
		}
	} else {
		// Only write operations that completed synchronously need to free up
		// hid_buffer. For reads, copy_transfer_data() handles that process.
		if (!direction_in)
			safe_free(transfer_priv->hid_buffer);

		if (size == 0) {
			usbi_err(ctx, "program assertion failed - no data was transferred");
			size = 1;
		}
		if (size > (size_t)length) {
			usbi_err(ctx, "OVERFLOW!");
			r = LIBUSB_ERROR_OVERFLOW;
		}
		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
		wfd.overlapped->InternalHigh = size;
	}

	transfer_priv->pollable_fd = wfd;
	transfer_priv->interface_number = (uint8_t)current_interface;

	return r;
}

static int hid_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	HANDLE hid_handle;
	int current_interface;

	CHECK_HID_AVAILABLE;

	current_interface = transfer_priv->interface_number;
	hid_handle = handle_priv->interface_handle[current_interface].api_handle;
	CancelIo(hid_handle);

	return LIBUSB_SUCCESS;
}

static int hid_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	HANDLE hid_handle;
	int current_interface;

	CHECK_HID_AVAILABLE;

	// Flushing the queues on all interfaces is the best we can achieve
	for (current_interface = 0; current_interface < USB_MAXINTERFACES; current_interface++) {
		hid_handle = handle_priv->interface_handle[current_interface].api_handle;
		if (HANDLE_VALID(hid_handle))
			HidD_FlushQueue(hid_handle);
	}

	return LIBUSB_SUCCESS;
}

static int hid_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	HANDLE hid_handle;
	int current_interface;

	CHECK_HID_AVAILABLE;

	current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
	if (current_interface < 0) {
		usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	usbi_dbg("matched endpoint %02X with interface %d", endpoint, current_interface);
	hid_handle = handle_priv->interface_handle[current_interface].api_handle;

	// No endpoint selection with Microsoft's implementation, so we try to flush the
	// whole interface. Should be OK for most case scenarios
	if (!HidD_FlushQueue(hid_handle)) {
		usbi_err(ctx, "Flushing of HID queue failed: %s", windows_error_str(0));
		// Device was probably disconnected
		return LIBUSB_ERROR_NO_DEVICE;
	}

	return LIBUSB_SUCCESS;
}

// This extra function is only needed for HID
static int hid_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	int r = LIBUSB_TRANSFER_COMPLETED;
	uint32_t corrected_size = io_size;

	if (transfer_priv->hid_buffer != NULL) {
		// If we have a valid hid_buffer, it means the transfer was async
		if (transfer_priv->hid_dest != NULL) { // Data readout
			if (corrected_size > 0) {
				// First, check for overflow
				if (corrected_size > transfer_priv->hid_expected_size) {
					usbi_err(ctx, "OVERFLOW!");
					corrected_size = (uint32_t)transfer_priv->hid_expected_size;
					r = LIBUSB_TRANSFER_OVERFLOW;
				}

				if (transfer_priv->hid_buffer[0] == 0) {
					// Discard the 1 byte report ID prefix
					corrected_size--;
					memcpy(transfer_priv->hid_dest, transfer_priv->hid_buffer + 1, corrected_size);
				} else {
					memcpy(transfer_priv->hid_dest, transfer_priv->hid_buffer, corrected_size);
				}
			}
			transfer_priv->hid_dest = NULL;
		}
		// For write, we just need to free the hid buffer
		safe_free(transfer_priv->hid_buffer);
	}

	itransfer->transferred += corrected_size;
	return r;
}


/*
 * Composite API functions
 */
static int composite_init(int sub_api, struct libusb_context *ctx)
{
	return LIBUSB_SUCCESS;
}

static int composite_exit(int sub_api)
{
	return LIBUSB_SUCCESS;
}

static int composite_open(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	int r = LIBUSB_ERROR_NOT_FOUND;
	uint8_t i;
	// SUB_API_MAX + 1 as the SUB_API_MAX pos is used to indicate availability of HID
	bool available[SUB_API_MAX + 1] = { 0 };

	for (i = 0; i < USB_MAXINTERFACES; i++) {
		switch (priv->usb_interface[i].apib->id) {
		case USB_API_WINUSBX:
			if (priv->usb_interface[i].sub_api != SUB_API_NOTSET)
				available[priv->usb_interface[i].sub_api] = true;
			break;
		case USB_API_HID:
			available[SUB_API_MAX] = true;
			break;
		default:
			break;
		}
	}

	for (i = 0; i < SUB_API_MAX; i++) { // WinUSB-like drivers
		if (available[i]) {
			r = usb_api_backend[USB_API_WINUSBX].open(i, dev_handle);
			if (r != LIBUSB_SUCCESS)
				return r;
		}
	}

	if (available[SUB_API_MAX]) // HID driver
		r = hid_open(SUB_API_NOTSET, dev_handle);

	return r;
}

static void composite_close(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	uint8_t i;
	// SUB_API_MAX + 1 as the SUB_API_MAX pos is used to indicate availability of HID
	bool available[SUB_API_MAX + 1] = { 0 };

	for (i = 0; i < USB_MAXINTERFACES; i++) {
		switch (priv->usb_interface[i].apib->id) {
		case USB_API_WINUSBX:
			if (priv->usb_interface[i].sub_api != SUB_API_NOTSET)
				available[priv->usb_interface[i].sub_api] = true;
			break;
		case USB_API_HID:
			available[SUB_API_MAX] = true;
			break;
		default:
			break;
		}
	}

	for (i = 0; i < SUB_API_MAX; i++) { // WinUSB-like drivers
		if (available[i])
			usb_api_backend[USB_API_WINUSBX].close(i, dev_handle);
	}

	if (available[SUB_API_MAX]) // HID driver
		hid_close(SUB_API_NOTSET, dev_handle);
}

static int composite_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	return priv->usb_interface[iface].apib->
		claim_interface(priv->usb_interface[iface].sub_api, dev_handle, iface);
}

static int composite_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	return priv->usb_interface[iface].apib->
		set_interface_altsetting(priv->usb_interface[iface].sub_api, dev_handle, iface, altsetting);
}

static int composite_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);

	return priv->usb_interface[iface].apib->
		release_interface(priv->usb_interface[iface].sub_api, dev_handle, iface);
}

static int composite_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	struct libusb_config_descriptor *conf_desc;
	WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *)transfer->buffer;
	int iface, pass, r;

	// Interface shouldn't matter for control, but it does in practice, with Windows'
	// restrictions with regards to accessing HID keyboards and mice. Try to target
	// a specific interface first, if possible.
	switch (LIBUSB_REQ_RECIPIENT(setup->request_type)) {
	case LIBUSB_RECIPIENT_INTERFACE:
		iface = setup->index & 0xFF;
		break;
	case LIBUSB_RECIPIENT_ENDPOINT:
		r = libusb_get_active_config_descriptor(transfer->dev_handle->dev, &conf_desc);
		if (r == LIBUSB_SUCCESS) {
			iface = get_interface_by_endpoint(conf_desc, (setup->index & 0xFF));
			libusb_free_config_descriptor(conf_desc);
			break;
		}
		// Fall through if not able to determine interface
	default:
		iface = -1;
		break;
	}

	// Try and target a specific interface if the control setup indicates such
	if ((iface >= 0) && (iface < USB_MAXINTERFACES)) {
		usbi_dbg("attempting control transfer targeted to interface %d", iface);
		if (priv->usb_interface[iface].path != NULL) {
			r = priv->usb_interface[iface].apib->submit_control_transfer(priv->usb_interface[iface].sub_api, itransfer);
			if (r == LIBUSB_SUCCESS)
				return r;
		}
	}

	// Either not targeted to a specific interface or no luck in doing so.
	// Try a 2 pass approach with all interfaces.
	for (pass = 0; pass < 2; pass++) {
		for (iface = 0; iface < USB_MAXINTERFACES; iface++) {
			if (priv->usb_interface[iface].path != NULL) {
				if ((pass == 0) && (priv->usb_interface[iface].restricted_functionality)) {
					usbi_dbg("trying to skip restricted interface #%d (HID keyboard or mouse?)", iface);
					continue;
				}
				usbi_dbg("using interface %d", iface);
				r = priv->usb_interface[iface].apib->submit_control_transfer(priv->usb_interface[iface].sub_api, itransfer);
				// If not supported on this API, it may be supported on another, so don't give up yet!!
				if (r == LIBUSB_ERROR_NOT_SUPPORTED)
					continue;
				return r;
			}
		}
	}

	usbi_err(ctx, "no libusb supported interfaces to complete request");
	return LIBUSB_ERROR_NOT_FOUND;
}

static int composite_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer) {
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	int current_interface;

	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
	if (current_interface < 0) {
		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	return priv->usb_interface[current_interface].apib->
		submit_bulk_transfer(priv->usb_interface[current_interface].sub_api, itransfer);
}

static int composite_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer) {
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
	int current_interface;

	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
	if (current_interface < 0) {
		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	return priv->usb_interface[current_interface].apib->
		submit_iso_transfer(priv->usb_interface[current_interface].sub_api, itransfer);
}

static int composite_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
{
	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	int current_interface;

	current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
	if (current_interface < 0) {
		usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
		return LIBUSB_ERROR_NOT_FOUND;
	}

	return priv->usb_interface[current_interface].apib->
		clear_halt(priv->usb_interface[current_interface].sub_api, dev_handle, endpoint);
}

static int composite_abort_control(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);

	return priv->usb_interface[transfer_priv->interface_number].apib->
		abort_control(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer);
}

static int composite_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);

	return priv->usb_interface[transfer_priv->interface_number].apib->
		abort_transfers(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer);
}

static int composite_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
{
	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
	int r;
	uint8_t i;
	bool available[SUB_API_MAX];

	for (i = 0; i < SUB_API_MAX; i++)
		available[i] = false;

	for (i = 0; i < USB_MAXINTERFACES; i++) {
		if ((priv->usb_interface[i].apib->id == USB_API_WINUSBX)
				&& (priv->usb_interface[i].sub_api != SUB_API_NOTSET))
			available[priv->usb_interface[i].sub_api] = true;
	}

	for (i = 0; i < SUB_API_MAX; i++) {
		if (available[i]) {
			r = usb_api_backend[USB_API_WINUSBX].reset_device(i, dev_handle);
			if (r != LIBUSB_SUCCESS)
				return r;
		}
	}

	return LIBUSB_SUCCESS;
}

static int composite_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
{
	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);

	return priv->usb_interface[transfer_priv->interface_number].apib->
		copy_transfer_data(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer, io_size);
}

#endif /* !USE_USBDK */